To see the other types of publications on this topic, follow the link: Distributed network management.
Dissertations / Theses on the topic 'Distributed network management'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Distributed network management.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Coffield, D. T. "Network and distributed systems management." Thesis, Lancaster University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380320.
Full text
2
Lim, Darren Tze Chang. "Distributed battery management system network architecture." Thesis, University of Canterbury. Electrical and Computer Engineering, 2004. http://hdl.handle.net/10092/5595.
Full textAbstract:
The design of a modular, flexible and extensible distributed CAN-based battery management system is examined in this thesis. The advent of next generation networks has placed an increasing demand for greater reliability from telecommunication power systems. A crucial component of the power system is the standby battery network. Battery networks are typically monitored by battery management systems. Existing management systems are more concerned with process level control methodology rather than system level organisation of the network architecture. Moreover, most existing systems are based on proprietary communication protocols. The proposed management solution addresses these local area network limitations, as well as the distribution of intelligence at the process level, integration between the local and wide area networks and transparency between the process and user levels.
The local network organisation is based on generic network nodes which perform management, monitoring and control activities through specialised hardware interfaces. Remote connectivity to the local network is facilitated through applet-servlet communication over the Internet. A modular design has been applied to the implementation of the node software to allow easy expandability of node functionality. The local battery network has been naturally and logically partitioned and a distributed data organisation has been adopted to facilitate transparency of data transfer from the process-level to the user-level via a well-defined communication channel. The system design is based on isolated concurrent processes that ensure system stability and successfully integrate the local control network with the wide network. A messaging system for the local CAN network has been formulated based on transmission of command, data and status messages related to battery management functionality. Performance analysis of the local network and the node organisation has shown the substantial capacity of the proposed system for handling the battery management application.
The designed battery network simulation model allows the performance evaluation of various battery application scenarios. The simulation model focuses on the generic components within the management system and encapsulates the primary features of the network organisation. The Extend simulation package has been used in the design of the model. The key criteria of the simulation model organisation and model block design are well defined. Limitations of the simulation package have also been identified.
3
Conner, Steven. "Automated distribution network planning with active network management." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28818.
Full textAbstract:
Renewable energy generation is becoming a major part of energy supply, often in the form of distributed generation (DG) connected to distribution networks. While growth has been rapid, there is awareness that limitations on spare capacity within distribution (and transmission) networks is holding back development. Developments are being shelved until new network reinforcements can be built, which may make some projects non-viable. Reinforcements are costly and often underutilised, typically only loaded to their limits for a few occasions during the year. In order to accommodate new DG without the high costs or delays, active network management (ANM) is being promoted in which generation and other network assets are controlled within the limits of the existing network. There is a great deal of complexity and uncertainty associated with developing ANM and devising coherent plans to accommodate new DG is challenging for Distribution Network Operators (DNOs). As such, there is a need for robust network planning tools that can explicitly handle ANM and which can be trusted and implemented easily. This thesis describes the need for and the development of a new distribution expansion planning framework that provides DNOs with a better understanding of the impacts created by renewable DG and the value of ANM. This revolves around a heuristic planning framework which schedules necessary upgrades in power lines and transformers associated with changes in demand as well as those driven by the connection of DG. Within this framework a form of decentralised, adaptive control of DG output has been introduced to allow estimation of the impact of managing voltage and power flow constraints on the timing and need for network upgrades. The framework is initially deployed using simple scenarios but a further advance is the explicit use of time series to provide substantially improved estimates of the levels of curtailment implied by ANM. In addition, a simplified approach to incorporating demand side management has been deployed to facilitate understanding of the scope and role this may play in facilitating DG connections.
4
Torrente, Salvatore. "An object-oriented approach to distributed network management." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23757.
Full textAbstract:
Network management is concerned with monitoring, controlling and coordinating network elements for reliable end-to-end customer services. This thesis presents an object-oriented approach to distributed network management of heterogeneous network elements across multiple telecommunication network service provider domains. Specifically, we present a prototype network management approach using distributed object database management systems as a repository and manager of a standard network information model, and we present the results of object interaction across distributed object-oriented databases. In particular, we provide data which illustrates the advantages of an active and dynamic network management environment over static management information bases for fast and efficient telecommunications Operations, Administration, Maintenance and Provisioning (OAM&P) of end-to-end network services. Finally, we expand on distributed object-oriented systems and their role in future information networking architectures.
5
Wittner, Otto. "Emergent behavior based implements for distributed network management." Doctoral thesis, Norwegian University of Science and Technology, Department of Telematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1787.
Full textAbstract:
<p>Network and system management has always been of concern for telecommunication and computer system operators. The need for standardization was recognised already 20 years ago, hence several standards for network management exist today. However, the ever-increasing number of units connected to networks and the ever-increasing number of services being provided results in significant increased complexity of average network environments. This challenges current management systems. In addition to the general increase in complexity the trend among network owners and operators of merging several single service networks into larger, heterogeneous and complex full service networks challenges current management systems even further. The full service networks will require management systems more powerful than what is possible to realize basing systems purely on todays management standards. This thesis presents a distributed stochastic optimization algorithm which enables implementations of highly robust and efficient management tools. These tools may be integrated into management systems and potentially make the systems more powerful and better prepared for management of full service networks.</p><p>Emergent behavior is common in nature and easily observable in colonies of social insects and animals. Even an old oak tree can be viewed as an emergent system with its collection of interacting cells. Characteristic for any emergent system is how the overall behavior of the system emerge from many relatively simple, restricted behaviors interacting, e.g. a thousand ants building a trail, a flock of birds flying south or millions of cells making a tree grow. No centralized control exist, i.e. no single unit is in charge making global decisions. Despite distributed control, high work redundancy and stochastic behavior components, emergent systems tend to be very efficient problem solvers. In fact emergent systems tend to be both efficient, adaptive and robust which are three properties indeed desirable for a network management system. The algorithm presented in this thesis relates to a class of emergent behavior based systems known as swarm intelligence systems, i.e. the algorithm is potentially efficient, adaptive and robust.</p><p>On the contrary to other related swarm intelligence algorithms, the algorithm presented has a thorough formal foundation. This enables a better understanding of the algorithm’s potentials and limitations, and hence enables better adaptation of the algorithm to new problem areas without loss of efficiency, adaptability or robustness. The formal foundations are based on work by Reuven Rubinstein on cross entropy driven optimization. The transition from Ruinstein’s centralized and synchronous algorithm to a distributed and asynchronous algorithm is described, and the distributed algorithm’s ability to solve complex problems (NP-complete) efficiently is demonstrated.</p><p>Four examples of how the distributed algorithm may be applied in a network management context are presented. A system for finding near optimal patterns of primary/backup paths together with a system for finding cyclic protection paths in mesh networks demonstrate the algorithm’s ability to act as a tool helping management system to ensure quality of service. The algorithm’s potential as a management policy implementation mechanism is also demonstrated. The algorithm’s adaptability is shown to enable resolution of policy conflicts in a soft manner causing as little loss as possible. Finally, the algorithm’s ability to find near optimal paths (i.e. sequences) of resources in networks of large scale is demonstrated.</p>
6
Ari, Ismail. "Design and management of globally-distributed network caches /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2004. http://uclibs.org/PID/11984.
Full text
7
Athanasiadis, Dimitrios. "Decentralising active network management through distributed constraint optimisation." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27880.
Full textAbstract:
Electricity networks are becoming more complex due to the introduction of distributed energy sources. The power grid will face fundamental changes in its structure and behaviour. In addition, new technologies will be required in order to maintain the stability of the network. A key enabling technology for the future power networks is autonomous distribution networks which operate in cooperation with distributed grid intelligence and active network management. Local control can be achieved through fast control and communications and needs to be coordinated with the overall system controls. The primary issues for distribution network operation with a high penetration of distributed resources is power flow management as well as voltage control. Active Network Management can be described as the control and management of generation and load in distribution networks. The main concept is to satisfy network limits such as voltage, power and frequency while at the same time increase the connected generation output with the minimum cost. There is a need for coordination between generators to maintain the balance in the network and avoid investment costs. This thesis considers the introduction of Distributed Constraint Optimisation as a way of providing Active Network Management. It is an agent-based coordination method that is able to coordinate generators’ output without violation of network constraints. This method, which is drawn from the Artificial Intelligence community and was previously used for smaller problems such as meeting scheduling, is studied and evaluated for use in power systems networks in order to provide solutions in a decentralised way. Case studies consider both DC and AC power flow management and the solution of the economic dispatch problem. DC power flow management under DCOP provides optimal solutions for radial networks while AC power flow management is examined from a theoretical standpoint until the limitations of distributed constrained optimisation software are addressed.
8
Wang, Baoyu. "An architecture for domain based distributed systems management." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277397.
Full text
9
Balamuru, Vinay Gopal. "The Role of Intelligent Mobile Agents in Network Management and Routing." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2736/.
Full textAbstract:
In this research, the application of intelligent mobile agents to the management of distributed network environments is investigated. Intelligent mobile agents are programs which can move about network systems in a deterministic manner in carrying their execution state. These agents can be considered an application of distributed artificial intelligence where the (usually small) agent code is moved to the data and executed locally. The mobile agent paradigm offers potential advantages over many conventional mechanisms which move (often large) data to the code, thereby wasting available network bandwidth. The performance of agents in network routing and knowledge acquisition has been investigated and simulated. A working mobile agent system has also been designed and implemented in JDK 1.2.
10
Everingham, Michael A. "Proposed management architecture for managing a distributed network information system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA297890.
Full textAbstract:
Thesis (M.S. in Information Technology Management) Naval Postgraduate School, March 1995.<br>"March 1995." Thesis advisor(s): M. Suh, W.B. Short. Includes bibliographical references. Also available online.
11
Askgaard, Jens Martin Breivik. "Sea Cage Gateway - A Distributed Sensor Management Network in ActorFrame." Thesis, Norwegian University of Science and Technology, Department of Telematics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10139.
Full textAbstract:
<p>This master thesis has been written in connection with the ongoing Sea Cage Gateway (SCG) project, a project investigating the possibility of remotely administering fish farming facilities. These facilities consist of sea cages placed offshore and connected to the mainland through wireless communication technologies. The sea cages all contain a number of sensors optimizing production and increasing safety. Not only must this sensor data be read, it must also be transported, collected, interpreted, handled, saved and retrieved. In addition, it is necessary to provide backup communication links in case of failures in the main communication systems. The system should be as autonomous as possible, allowing it to be unmanned for longer periods of time. This thesis has further investigated the possibility of remotely controlling and administering a fish farm through distributed nodes over wireless communication links. As a basis for this thesis domain descriptions from previous master theses written in connection with the SCG-project have been used. This thesis has also aimed to collect inspiration from other domains and concepts which have similarities with the SCG-project. With the increasing numbers of nodes and communication links present at the fish farm installations, areas such as grid computing and sensor networks have many applicable principles for the SCG-system. These principles have been integrated into the system design to give the basis for further such functionality in the SCG-domain. In addition to the areas of grid computing and sensor networks, the current and latest wireless communication technologies available for providing the services required by the SCG-system have been presented. The communication links also influence the system design since their connection types must be handled by the SCG-system elements. The SCG-system proposed has been designed and implemented with ActorFrame. The implemented system has functioned as a demonstrator for the main principles presented in the design. It has incorporated a GPS-receiver and a GPRS-modem to represent a sensor on a sea cage and a redundant communication link. The system implemented reports GPS-data to a central unit and issues alerts upon sensor data deviations (sea cage out of position). Furthermore, the demonstrator can detect a failed communication link and switch to the backup GPRS-modem, generate alarms, and continue to provide basic services. All elements and their status are reported and registered in a database and are presented through a dynamic web interface. The demonstrator has shown that ActorFrame can be utilized to provide the necessary functionality the SCG-domain requires. A few improvements are proposed for the framework to increase the flexibility and performance of the system, especially in the area of handling the distribution of actors on independent nodes and how the heterogeneous network technologies present in SCG-system require a higher-level of network-awareness on behalf of the application. This thesis has also suggested several possible extensions and future areas of work.</p>
12
Song, Terence Min Khian. "Supporting network visualisation, control and management in distributed virtual worlds." Thesis, University of Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492601.
Full textAbstract:
As the demand for greater observability and controllability increases, an intuitive user interface and the ability to visualise and interact with complex relational structures will be essential for the successful management of next generation networks and services. With object-oriented architectures, interfaces, and information models becoming the fundamental approach to advance information networks, a three-dimensional virtual world, with its higher-level of semantic interaction, is a natural choice to provide corresponding paradigm shift in perception, interaction, and collaborative capabilities.
13
Rakotoarivelo, Thierry Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Distributed discovery and management of alternate internet paths with enhanced quality of service." Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/27316.
Full textAbstract:
The convergence of recent technology advances opens the way to new ubiquitous environments, where network-enabled devices collectively form invisible pervasive computing and networking environments around the users. These users increasingly require extensive applications and capabilities from these devices. Recent approaches propose that cooperating service providers, at the edge of the network, offer these required capabilities (i.e services), instead of having them directly provided by the devices. Thus, the network evolves from a plain communication medium into an endless source of services. Such a service, namely an overlay application, is composed of multiple distributed application elements, which cooperate via a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS on the communication paths of the corresponding overlay association. This thesis asserts and shows that it is possible to provide QoS to an overlay application by using alternate Internet paths resulting from the compositions of independent consecutive paths. Moreover, this thesis also demonstrates that it is possible to discover, select and compose these independent paths in a distributed manner within an community comprising a limited large number of autonomous cooperating peers, such as the fore-mentioned service providers. Thus, the main contributions of this thesis are i) a comprehensive description and QoS characteristic analysis of these composite alternate paths, and ii) an original architecture, termed SPAD (Super-Peer based Alternate path Discovery), which allows the discovery and selection of these alternate paths in a distributed manner. SPAD is a fully distributed system with no single point of failure, which can be easily and incrementally deployed on the current Internet. It empowers the end-users at the edge of the network, allowing them to directly discover and utilize alternate paths.
14
Hildin, John. "NETWORK-BASED DISTRIBUTED DATA ACQUISITION AND RECORDING FOR SMALL SYSTEMS." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604469.
Full textAbstract:
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada<br>Some of the first applications of network-based data acquisition systems have been for large
aircraft. These systems contained numerous network nodes including data acquisition units,
switches, recorders, network management units, and others. One of the desirable aspects of a
networked-based system is the ability to scale such a system to meet increasing test
requirements. Similarly, these systems lend themselves to scaling down, as well, to meet the
testing needs of smaller test articles. These needs may include fewer nodes and/or physically
smaller components. The testing of smaller vehicles places slightly different requirements on the
testing process. In general, there is a greater need for real-time analysis, flexibility and ad-hoc
testing. This paper will attempt to show how a small to medium sized test article can benefit
from the same powerful, feature-rich network-based data acquisition and recording system as
used on larger programs. The paper will also show how a smaller system can deliver on this
promise without sacrificing performance and functionality.
15
Jeon, Sung-eok. "Near-Optimality of Distributed Network Management with a Machine Learning Approach." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16136.
Full textAbstract:
An analytical framework is developed for distributed management of large networks where each node makes locally its decisions. Two issues remain open. One is whether a distributed algorithm would result in a near-optimal management. The other is the complexity, i.e., whether a distributed algorithm would scale gracefully with a network size. We study these issues through modeling, approximation, and randomized distributed algorithms. For near-optimality issue, we first derive a global probabilistic model of network management variables which characterizes the complex spatial dependence of the variables. The
spatial dependence results from externally imposed management constraints and internal properties of communication environments. We then apply probabilistic graphical models in machine learning to show when and whether the global model can be approximated by a local model. This study results in a sufficient condition for distributed management to be nearly optimal. We then show how to obtain a near-optimal configuration through decentralized adaptation of local configurations.
We next derive a near-optimal distributed inference algorithm based on the derived local model. We characterize the trade-off between near-optimality and complexity of distributed and statistical management. We validate our formulation and theory through simulations.
16
Negi, Chandan Singh. "Using network management systems to detect Distributed Denial of Service Attacks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA397257.
Full textAbstract:
Thesis (M.S. in Information Systems Technology and M.S. in Computer Science)--Naval Postgraduate School, Sept. 2001.<br>Thesis advisors, Bordetsky, Alex ; Clark, Paul. "September 2001." Includes bibliographical references (p. 115-117). Also available in print.
17
Sueverachai, Thanakorn. "Design and Implementation ofa Network Search Node." Thesis, KTH, Kommunikationsnät, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141424.
Full textAbstract:
Networked systems, such as cloud infrastructures, are growing in size and complexity.They hold and generate a vast amount of configuration and operational data, whichis maintained in various locations and formats, and changes at various time scales.A wide range of protocols and technologies is used to access this data for networkmanagement tasks. A concept called ‘network search’ is introduced to make all thisdata available in real-time through a search platform with a uniform interface, whichenables location-independent access through search queries. Network search requires a network of search nodes, where the nodes have identicalcapabilities and work cooperatively to process search queries in a peer-to-peer fashion.A search node should indicate good performance results in terms of low query responsetimes, high throughputs, and low overhead costs and should scale to large networkedsystems with at least hundred thousands nodes. This thesis contributes in several aspects towards the design and implementation of anetwork search node. We designed a search node that includes three major components,namely, a real-time data sensing component, a real-time database, and a distributedquery-processing component. The design takes indexing of search terms and concurrencyof query processing into consideration, which accounts for fast response timesand high throughput of search queries. We implemented a network search node as asoftware package that runs on a server that provides a cloud service, and we evaluatedits performance on a cloud testbed of nine servers. The performance measurementssuggest that a network search system based on our design can process queries at lowquery latencies for a high query load, while maintaining a low overhead of computationalresources.
18
Kravets, Robin H. "Cooperative solutions to the dynamic management of communication resources." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/8195.
Full text
19
Tran, Allen Quoc-Luan. "A network management facility for a fault-tolerant distributed information retrieval system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0010/MQ53394.pdf.
Full text
20
Gill, Simon. "Maximising the benefit of distributed wind generation through intertemporal Active Network Management." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25579.
Full textAbstract:
The role of distribution networks is changing. There is a significant drive, influenced by climate change and security of supply issues, to move electricity generation towards renewable technologies. This is leading to an increase in demand for renewable generation connections at the distribution network level and putting pressure on distribution network operators to change the 'fit-and-forget' philosophy of network operation to include more active approaches. In the UK this is seen through the development of Active Network Management schemes which manage distributed generation in real-time, applying constraints when required to maintain network limits. In parallel, technologies have been developed that are capable of providing intertemporal flexibility, of which two particular examples are energy storage and flexible demand. The objective of the thesis is to answer the questions: How can energy storage and flexible demand be scheduled in a second-generation Active Network Management scheme? And how should they be operated to gain most benefit from distributed wind generation? To answer these questions, the thesis develops and uses tools to study the optimisation of second-generation Active Network Management schemes including intertemporal technologies. The tools developed include a Dynamic Optimal Power Flow algorithm for management of energy storage and flexible demand. The thesis provides the first fully flexible model of energy storage in this context, the first implementation of principles-of-access in an optimal power flow, and the first detailed study of the role of energy storage and flexible demand in managing thermal limits and reducing curtailment of distributed wind generation. The thesis also develops the theory of Dynamic Locational Marginal Pricing based on the economic information contained in an optimal solution to a Dynamic Optimal Power Flow. The thesis shows this to be a useful way of understanding the economic impact of intertemporal flexibility and monetary flows in markets which contain them. The thesis goes on to provide a detailed report of the application of Dynamic Optimal Power Flow and Dynamic Locational Marginal Pricing to an islanded Active Network Management scheme currently in deployment in the UK. This highlights the ability of the tools developed to contribute to future projects. A conclusions of the thesis is that DOPF provides a useful method of scheduling flexible devices such as energy storage and power systems. It takes full account of network constraints and limitations, and as applied in this thesis, the most complete models of the intertemporal effects of energy storage and flexible demand to date. The studies contained in the thesis show that energy storage and flexible demand can increase the benefit of distributed wind generation in Active Network Management by minimising curtailment and transferring generated electricity to periods during which the energy has greatest value in offsetting expensive, fossil fuel based generation. The thesis notes the importance of a useful definition of the 'benefit' of wind generation in terms of global objectives such as minimising emissions rather than interim objectives such as maximising generation from renewables. The thesis discusses the importance of losses in energy storage, and the relationship of storage and network losses with curtailment of wind and the lost opportunity of generating electricity. In terms of losses, the extension of existing economic analysis methods leads to the result that flexibility will only operate between time-steps where the ratio of prices is greater than the round-trip losses of the store. Within this constraint, effective use of energy storage is shown to result from regular charging and discharging. The comparison between energy storage and flexible demand shows that where there are few losses associated with flexibility in demand it is significantly more successful than energy storage at mitigating the effects of variability in wind. The final study of an islanded distribution network with wind curtailment, concludes that energy storage is less effective that flexible demand at reducing wind curtailment, but can provide benefit through management of peak demand. Flexible demand, in the form of flexible domestic electric heating, is shown to have the ability to provide a significant benefit in terms of reduced wind curtailment. This ability is further enhanced for island situations if demand has a frequency-responsive component.
21
Montanari, Luca. "A Network Function Virtualization Architecture for Distributed IoT Gateways." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13345/.
Full textAbstract:
La virtualizzazione permette a diverse applicazioni di condividere lo stesso dispositivo IoT. Tuttavia, in ambienti eterogenei, reti di dispositivi IoT virtualizzati fanno emergere nuove sfide, come la necessità di fornire on-the-fly e in maniera dinamica, elastica e scalabile, gateway. NFV è un paradigma progettato per affrontare queste nuove sfide. Esso sfrutta tecnologie di virtualizzazione standard per consolidare specifici elementi di rete su generico hardware commerciale. Questa tesi presenta un'architettura
NFV per gateway IoT distribuiti, nella quale istanze software dei moduli dei gateway sono ospitate su un'infrastruttura NFV distribuita, la quale è operata e gestita da un IoT gateway Provider. Considereremo diversi IoT Provider, ciascuno con le proprie marche, o loro combinazioni, di sensori e attuatori/robot. Ipotizzeremo
che gli ambienti dei provider siano geograficamente distribuiti, per un'efficiente copertura di regioni estese. I sensori e gli attuatori possono essere utilizzati da una varietà di applicazioni, ciascuna delle quali può avere diversi requisiti per interfacce e QoS (latenza, throughput, consumi, ecc...). L'infrastruttura NFV consente di effettuare un deployment elastico, dinamico e scalabile dei moduli gateway in questo ambiente eterogeneo e distribuito. Inoltre, l'architettura proposta è in grado di riutilizzare moduli il cui deployment è stato precedentemente compiuto. Ciò è ottenuto
attraverso Service Function Chaining e un'orchestrazione dinamica a runtime. Infine, presenteremo un prototipo basato sulla piattaforma OpenStack.
22
Zhuang, Yan. "A scalable web-based distributed network management architecture and the manager MIB design." Thesis, University of Macau, 1998. http://umaclib3.umac.mo/record=b1637002.
Full text
23
Raza, Syed Kamran. "A plug-and-play approach with distributed computing alternatives for network configuration management." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0003/MQ43346.pdf.
Full text
24
Raza, Syed Kamran Carleton University Dissertation Engineering Systems and Computer. "A Plug-and-play approach with distributed computing alternatives for network configuration management." Ottawa, 1999.
Find full text
25
Neel, James O'Daniell. "Analysis and Design of Cognitive Radio Networks and Distributed Radio Resource Management Algorithms." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29998.
Full textAbstract:
Cognitive radio is frequently touted as a platform for implementing dynamic distributed radio resource management algorithms. In the envisioned scenarios, radios react to measurements of the network state and change their operation according to some goal driven algorithm. Ideally this flexibility and reactivity yields tremendous gains in performance. However, when the adaptations of the radios also change the network state, an interactive decision process is spawned and once desirable algorithms can lead to catastrophic failures when deployed in a network.
This document presents techniques for modeling and analyzing the interactions of cognitive radio for the purpose of improving the design of cognitive radio and distributed radio resource management algorithms with particular interest towards characterizing the algorithms' steady-state, convergence, and stability properties. This is accomplished by combining traditional engineering and nonlinear programming analysis techniques with techniques from game to create a powerful model based approach that permits rapid characterization of a cognitive radio algorithm's properties. Insights gleaned from these models are used to establish novel design guidelines for cognitive radio design and powerful low-complexity cognitive radio algorithms.
This research led to the creation of a new model of cognitive radio network behavior, an extensive number of new results related to the convergence, stability, and identification of potential and supermodular games, numerous design guidelines, and several novel algorithms related to power control, dynamic frequency selection, interference avoidance, and network formation. It is believed that by applying the analysis techniques and the design guidelines presented in this document, any wireless engineer will be able to quickly develop cognitive radio and distributed radio resource management algorithms that will significantly improve spectral efficiency and network and device performance while removing the need for significant post-deployment site management.<br>Ph. D.
26
Ding, Fei. "Smart Distribution System Automation: Network Reconfiguration and Energy Management." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1417291114.
Full text
27
Guardalben, Lucas. "Communication between nodes for autonomic and distributed management." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/12877.
Full textAbstract:
Doutoramento conjunto MAPi em Informática<br>Over the last decade, the most widespread approaches for traditional management
were based on the Simple Network Management Protocol (SNMP) or Common
Management Information Protocol (CMIP). However, they both have several problems
in terms of scalability, due to their centralization characteristics. Although
the distributed management approaches exhibit better performance in terms of
scalability, they still underperform regarding communication costs, autonomy, extensibility,
exibility, robustness, and cooperation between network nodes. The
cooperation between network nodes normally requires excessive overheads for synchronization
and dissemination of management information in the network. For
emerging dynamic and large-scale networking environments, as envisioned in Next
Generation Networks (NGNs), exponential growth in the number of network devices
and mobile communications and application demands is expected. Thus, a
high degree of management automation is an important requirement, along with
new mechanisms that promote it optimally and e ciently, taking into account the
need for high cooperation between the nodes. Current approaches for self and autonomic
management allow the network administrator to manage large areas, performing
fast reaction and e ciently facing unexpected problems. The management
functionalities should be delegated to a self-organized plane operating within the
network, that decrease the network complexity and the control information ow,
as opposed to centralized or external servers. This Thesis aims to propose and
develop a communication framework for distributed network management which
integrates a set of mechanisms for initial communication, exchange of management
information, network (re) organization and data dissemination, attempting
to meet the autonomic and distributed management requirements posed by NGNs.
The mechanisms are lightweight and portable, and they can operate in di erent
hardware architectures and include all the requirements to maintain the basis for
an e cient communication between nodes in order to ensure autonomic network
management. Moreover, those mechanisms were explored in diverse network conditions
and events, such as device and link errors, di erent tra c/network loads
and requirements. The results obtained through simulation and real experimentation
show that the proposed mechanisms provide a lower convergence time, smaller
overhead impact in the network, faster dissemination of management information,
increase stability and quality of the nodes associations, and enable the support for
e cient data information delivery in comparison to the base mechanisms analyzed.
Finally, all mechanisms for communication between nodes proposed in this Thesis,
that support and distribute the management information and network control
functionalities, were devised and developed to operate in completely decentralized
scenarios.<br>Durante a última década, protocolos como Simple Network Management Protocol
(SNMP) ou Common Management Information Protocol (CMIP) foram as abordagens
mais comuns para a gestão tradicional de redes. Essas abordagens têm
vários problemas em termos de escalabilidade, devido às suas características de
centralização. Apresentando um melhor desempenho em termos de escalabilidade,
as abordagens de gestão distribuída, por sua vez, são vantajosas nesse sentido,
mas também apresentam uma série de desvantagens acerca do custo elevado de
comunicação, autonomia, extensibilidade, exibilidade, robustez e cooperação entre
os nós da rede. A cooperação entre os nós presentes na rede é normalmente
a principal causa de sobrecarga na rede, uma vez que necessita de colectar, sincronizar
e disseminar as informações de gestão para todos os nós nela presentes.
Em ambientes dinâmicos, como é o caso das redes atuais e futuras, espera-se um
crescimento exponencial no número de dispositivos, associado a um grau elevado
de mobilidade dos mesmos na rede. Assim, o grau elevado de funções de automatiza
ção da gestão da rede é uma exigência primordial, bem como o desenvolvimento
de novos mecanismos e técnicas que permitam essa comunicação de forma optimizada
e e ciente. Tendo em conta a necessidade de elevada cooperação entre
os elementos da rede, as abordagens atuais para a gestão autonómica permitem
que o administrador possa gerir grandes áreas de forma rápida e e ciente frente
a problemas inesperados, visando diminuir a complexidade da rede e o uxo de
informações de controlo nela gerados. Nas gestões autonómicas a delegação de
operações da rede é suportada por um plano auto-organizado e não dependente
de servidores centralizados ou externos. Com base nos tipos de gestão e desa os
acima apresentados, esta Tese tem como principal objetivo propor e desenvolver
um conjunto de mecanismos necessários para a criação de uma infra-estrutura
de comunicação entre nós, na tentativa de satisfazer as exigências da gestão auton
ómica e distribuída apresentadas pelas redes de futura geração. Nesse sentido,
mecanismos especí cos incluindo inicialização e descoberta dos elementos da rede,
troca de informação de gestão, (re) organização da rede e disseminação de dados
foram elaborados e explorados em diversas condições e eventos, tais como: falhas
de ligação, diferentes cargas de tráfego e exigências de rede. Para além disso, os
mecanismos desenvolvidos são leves e portáveis, ou seja, podem operar em diferentes
arquitecturas de hardware e contemplam todos os requisitos necessários para
manter a base de comunicação e ciente entre os elementos da rede. Os resultados
obtidos através de simulações e experiências reais comprovam que os mecanismos
propostos apresentam um tempo de convergência menor para descoberta e troca
de informação, um menor impacto na sobrecarga da rede, disseminação mais rápida
da informação de gestão, aumento da estabilidade e a qualidade das ligações entre
os nós e entrega e ciente de informações de dados em comparação com os mecanismos
base analisados. Finalmente, todos os mecanismos desenvolvidos que fazem
parte da infrastrutura de comunicação proposta foram concebidos e desenvolvidos
para operar em cenários completamente descentralizados.
28
Khan, Kashif. "A distributed computing architecture to enable advances in field operations and management of distributed infrastructure." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/a-distributed-computing-architecture-to-enable-advances-in-field-operations-and-management-of-distributed-infrastructure(a9181e99-adf3-47cb-93e1-89d267219e50).html.
Full textAbstract:
Distributed infrastructures (e.g., water networks and electric Grids) are difficult to manage due to their scale, lack of accessibility, complexity, ageing and uncertainties in knowledge of their structure. In addition they are subject to loads that can be highly variable and unpredictable and to accidental events such as component failure, leakage and malicious tampering. To support in-field operations and central management of these infrastructures, the availability of consistent and up-to-date knowledge about the current state of the network and how it would respond to planned interventions is argued to be highly desirable. However, at present, large-scale infrastructures are “data rich but knowledge poor”. Data, algorithms and tools for network analysis are improving but there is a need to integrate them to support more directly engineering operations. Current ICT solutions are mainly based on specialized, monolithic and heavyweight software packages that restrict the dissemination of dynamic information and its appropriate and timely presentation particularly to field engineers who operate in a resource constrained and less reliable environments. This thesis proposes a solution to these problems by recognizing that current monolithic ICT solutions for infrastructure management seek to meet the requirements of different human roles and operating environments (defined in this work as field and central sides). It proposes an architectural approach to providing dynamic, predictive, user-centric, device and platform independent access to consistent and up-to-date knowledge. This architecture integrates the components required to implement the functionalities of data gathering, data storage, simulation modelling, and information visualization and analysis. These components are tightly coupled in current implementations of software for analysing the behaviour of networks. The architectural approach, by contrast, requires they be kept as separate as possible and interact only when required using common and standard protocols. The thesis particularly concentrates on engineering practices in clean water distribution networks but the methods are applicable to other structural networks, for example, the electricity Grid. A prototype implementation is provided that establishes a dynamic hydraulic simulation model and enables the model to be queried via remote access in a device and platform independent manner.This thesis provides an extensive evaluation comparing the architecture driven approach with current approaches, to substantiate the above claims. This evaluation is conducted by the use of benchmarks that are currently published and accepted in the water engineering community. To facilitate this evaluation, a working prototype of the whole architecture has been developed and is made available under an open source licence.
29
Chen, Jun. "A distributed network management systems for user-controlled lightpath provisioning and its security requirements." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/26867.
Full textAbstract:
There is a growing trend for many large enterprises and other users to acquire their own optical networks. These customer-owned and managed networks bring cost saving benefits as well as management challenges, especially in the security aspect. In this thesis, a distributed network management system based on Service Oriented Architectures for customer-owned optical networks is presented. The system realizes User-Controlled Lightpath Provisioning and provides users the ability to make end-to-end connections across multiple administrative domains.
However, the current version of the system does not meet the security requirements of UCLP. This thesis also presents the research work on how to overcome the security challenge in customer-owned optical network management. The security requirements of the system are analyzed and the major difficulties are identified. Different access control models and security technologies are investigated. An access control mechanism based on Attribute Certificate is chosen for the future implementation of the UCLP system.
30
Luo, Tianyu. "Assessment of novel distributed control techniques to address network constraints with demand side management." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24979.
Full textAbstract:
The development of sustainable generation, a reliable electricity supply and affordable tariffs are the primary requirements to address the uncertainties in different future energy scenarios. Due to the predicted increase in Distributed Generation (DG) and load profile changes in future scenarios, there are significant operational and planning challenges facing netwrok operators. These changes in the power system distribution network require a new Active Network Management (ANM) control system to manage distribution constraint issues such as thermal rating, voltage, and fault levels. The future smart grid focuses on harnessing the control potential from demand side via bidirectional power flow, transparent information communication, and contractual customer participation. Demand Side Management (DSM) is considered as one of the effective solutions to defer network capacity reinforcement, increase energy efficiency, facilitate renewable access, and implement low carbon energy strategy. From the Distribution Network Operator's (DNO) perspective, the control opportunity from Demand Response (DR) and Decentralized Energy Resource (DER) contributes on capacity investment reduction, energy efficiency, and enable low carbon technologies. This thesis develops a new decentralized control system for dealing effectively with the constraint issues in the Medium Voltage (MV) distribution network. In the decentralized control system, two novel control approaches are proposed to autonomously relieve the network thermal constraint via DNO's direct control of the real power in network components during the operation period. The first approach, Demand Response for Power Flow Management (DR-PFM), implements the DSM peak clipping control of Active Demand (AD), whilst the second approach, Hybrid Control for Power Flow Management (HC-PFM), implements the hybrid control of both AD and DER. The novelty of these two new control algorithms consists in the application of a Constraint Satisfaction Problem (CSP) based programming model on decision making of the real power curtailment to relieve the network thermal overload. In the Constraint Programming (CP) model, three constraints are identified: a preference constraint, and a network constraint. The control approaches effectively solve the above constraint problem in the CSP model within 5 seconds' time response. The control performance is influenced by the pre-determined variable, domain and constraint settings. These novel control approaches take advantages on flexible control, fast response and demand participation enabling in the future smart grid.
31
Azevedo, João Pedro Coelho de. "Wireless distributed mobility management on a road scenario." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14936.
Full textAbstract:
Mestrado em Engenharia Eletrónica e Telecomunicações<br>In today's world, connectivity is an important requirement for the population.
People want and, in a broad range of cases, need to be connected
with each other and with the world. To share a video, attend
an e-meeting or just keep in touch with friends and family, Internet
is truly part of our everyday life. However, this massive growth of
the connected world presented a lot of challenges to the engineering
task-forces and research teams in computer networks. One of these
challenges is mobility.
The network mobility theme is not a recent matter in the networking
world since people want to reach the Internet everywhere and still be
able to do it like when at home. Several solutions have been presented
and applied over the years; however, with the expansion of vehicular
networks, new solutions must be presented in order to ful ll the requirements
of such networks.
In this work a study on the available mobility management solutions is
performed. The studied mobility management solutions include both
centralized and distributed solutions; however, the focus of the work
presented is in the distributed category. In this context an implementation
for a new distributed mobility management protocol, DMIPA,
suitable to be used in a vehicular environment is presented. This new
protocol aims to deliver mobility management in a distributed way,
avoiding the disadvantages of centralized solutions, even in networks
that do not provide any support for mobility without any hardware or
network changes.
Moreover, the protocol was tested in laboratory and on the road in
order to acquire real data about the performance and behaviour of
the implementation. These tests were based on the access technologies
IEEE 802.11g, commonly used in WiFi access points, and IEEE
802.11p, a technology tailored for vehicular networks.<br>Actualmente, a conectividade ubíqua é uma necessidade importante para a generalidade da população. As pessoas querem e, em muitos casos, têm a necessidade de estar ligadas entre si e com o mundo.
Para partilhar um vídeo, participar numa reunião online ou apenas
para manter contacto com os amigos e familiares, a Internet faz verdadeiramente parte do nosso dia-a-dia. No entanto, este crescimento
maciço do mundo online apresentou uma série de desafios às equipas
de engenharia e investigação em redes de computadores. Um desses
desafios é a mobilidade.
O tema da mobilidade na rede não é uma questão recente, uma vez que as pessoas desejam aceder à Internet em todos os lugares e querem
poder fazê-lo como se estivessem em casa. Várias soluções foram apresentadas e aplicadas ao longo dos anos; no entanto, com a expansão
das redes veiculares, novas soluções são necessárias de modo a cumprir
os requisitos de tais redes.
Neste trabalho foi realizado um estudo sobre as soluções de gestão de mobilidade disponíveis. As soluções de gestão de mobilidade estudadas incluem soluções centralizadas e distribuídas; no entanto, o foco do trabalho apresentado está nas soluções distribuídas. Neste contexto, é apresentada uma implementação de um novo protocolo de gestão distribuída de mobilidade, DMIPA, adequado para ser utilizado num ambiente veicular. Este novo protocolo pretende aplicar a gestão da mobilidade de forma distribuída pelos vários nós da rede, evitando as desvantagens de soluções centralizadas, mesmo em redes que não oferecem qualquer apoio à mobilidade, sem quaisquer mudanças de hardware ou de rede.
Além disso, o protocolo foi testado em laboratório e na estrada, a fim de obter dados reais sobre o seu desempenho e comportamento. Este teste foi realizado utilizando as tecnologias de acesso IEEE 802.11g, utilizado em pontos de acesso Wi-Fi, e IEEE 802.11p, uma tecnologia desenvolvida em especial para redes veiculares.
32
Robertson, James George. "New optimal power flow techniques to improve integration of distributed generation in responsive distribution networks." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10528.
Full textAbstract:
Climate change has brought about legally-binding targets for Scotland, the U.K. and the E.U. to reduce greenhouse gas emissions and source a share of overall energy consumption from renewable energy resources by 2020. With severe limitations in the transport and heating sectors the onus is on the electricity sector to provide a significant reduction in greenhouse gas emissions and introduce a substantial increase in renewable energy production. The most attractive renewable energy resources are located in the geographic extremes of the country, far from the large population densities and high voltage, high capacity transmission networks. This means that the majority of renewable generation technologies will need to connect to the conventionally passive, lower voltage distribution networks. The integration of Distributed Generation (DG) is severely restricted by the technical limitations of the passively managed lower voltage infrastructure. Long lead times and the capital expenditure of traditional electricity network reinforcement can significantly delay or make the economics of some renewable generation schemes unviable. To be able to quickly and cost-effectively integrate significant levels of DG, the conventional fit-and-forget approach will have to be evolved into a ‘connect-and-manage’ system using active network management (ANM) techniques. ANM considers the real-time variation in generation and demand levels and schedules electricity network control settings to alleviate system constraints and increase connectable capacity of DG. This thesis explores the extent to which real time adjustments to DG and network asset controller set-points could allow existing networks to accommodate more DG. This thesis investigates the use of a full AC OPF technique to operate and schedule in real time variables of ANM control in distribution networks. These include; DG real and reactive power output and on-load-tap-changing transformer set-points. New formulations of the full AC OPF problem including multi-objective functions, penalising unnecessary deviation of variable control settings, and a Receding-Horizon formulation are assessed. This thesis also presents a methodology and modelling environment to explore the new and innovative formulations of OPF and to assess the interactions of various control practices in real time. Continuous time sequential, single scenario, OPF analyses at a very short control cycle can lead to the discontinuous and unnecessary switching of network control set-points, particularly during the less onerous network operating conditions. Furthermore, residual current flow and voltage variation can also gave rise to undesirable network effects including over and under voltage excursion and thermal overloading of network components. For the majority of instances, the magnitude of constraint violation was not significant but the levels of occurrence gave occasional cause for concern. The new formulations of the OPF problem were successful in deterring any extreme and unsatisfactory effects. Results have shown significant improvements in the energy yield from non-firm renewable energy resources. Initial testing of the real time OPF techniques in a simple demonstration network where voltage rise restricted the headroom for installed DG capacity and energy yield, showed that the energy yield for a single DG increased by 200% from the fit-and-forget scenario. Extrapolation of the OPF technique to a network with multiple DGs from different types of renewable energy resources showed an increase of 216% from the fit-and-forget energy yield. In a much larger network case study, where thermal loading limits constrained further DG capacity and energy yield, the increase in energy yield was more modest with an average increase of 45% over the fit-and-forget approach. In the large network where thermal overloading prevailed there was no immediate alternative to real power curtailment. This work has demonstrated that the proposed ANM OPF schemes can provide an intelligent, more cost effective and quicker alternative to network upgrades. As a result, DNOs can have a better knowledge and understanding of the capabilities and technical limitations of their networks to absorb DG safely and securely, without the expense of conventional network reinforcement.
33
關振德 and Chun-tak Kwan. "A practical distributed garbage collection algorithm for message passing network with message delay." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31213157.
Full text
34
Kwan, Chun-tak. "A practical distributed garbage collection algorithm for message passing network with message delay /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18040147.
Full text
35
Prudich, Philip. "Dynamic Routing using an Overlay Network of Relays." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1128723813.
Full text
36
Alasadi, Emad Younis. "Enhancing network scalability by introducing mechanisms, architectures and protocols." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15874.
Full textAbstract:
In this thesis, three key issues that restrict networks from scaling up so as to be able to cope with the rapid increase in traffic are investigated and series of approaches are proposed and tested for overcoming them. Firstly, scalability limitations owing to the use of a broadcast mechanism in one collision domain are discussed. To address this matter, servers under software-defined network architectures for eliminating discovery messages (SSED) are designed in this thesis and a backbone of floodless packets in an SDN LAN network is introduced. SSED has an innovative mechanism for defining the relationship between the servers and SDN architecture. Experimental results, after constructing and applying an authentic testbed, verify that SSED has the ability to improve upon the scalability of the traditional mechanism in terms of the number of switches and hosts. This is achieved by removing broadcast packets from the data and control planes as well as offering a better response time. Secondly, the scalability restrictions from using routers and the default gateway mechanism are explained. In this thesis, multiple distributed subnets using SDN architecture and servers to eliminate router devices and the default gateway mechanism (MSSERD) are introduced, designed and implemented as the general backbone for scalable multiple LAN-based networks. MSSERD's proposed components handle address resolution protocol (ARP) discovery packets and general IP packets across different subnets. Moreover, a general view of the network is provided through a multi-subnets discovery protocol (MDP). A 23 computers testbed is built and the results verify that MSSERD scales up the number of subnets more than traditional approaches, enhances the efficiency significantly, especially with high load, improves performance 2.3 times over legacy mechanisms and substantially reduces complexity. Finally, most of the available distributed-based architectures for different domains are reviewed and the aggregation discovery mechanism analysed to establish their impact on network scalability. Subsequently, a general distributed-centralised architecture with open-level control plane (OLC) architecture and a dynamic discovery hierarchical protocol (DHP) is introduced to provide better scalability in an SDN network. OLC can scale up the network with high performance even during high traffic.
37
Morais, de Lima C. H. (Carlos Héracles). "Opportunistic resource and network management in autonomous packet access systems." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526201771.
Full textAbstract:
Abstract This thesis aims to evaluate networking aspects of autonomous packets access systems when dynamically and adaptively performing resource and network management. In this context, Quality of Service (QoS)-aware solutions for resource sharing and control (e.g., channel access, load control, interference management and routing techniques among others) in large-scale wireless networks are envisaged. We propose and investigate distributed coordination mechanisms for controlling the co-channel interference generated in multi-tier coexistence scenarios consisting of macrocells underlaid with short-range small cells. The rationale behind employing such mechanism is to opportunistically reuse resources without compromising ongoing transmissions on the overlaid macrocells, while still guaranteeing QoS in both tiers. To mitigate the resulting co-channel interference, the underlaid tiers of small cells use distributed mechanism that relies on minimal signaling exchange, e.g., the Time Division Duplexing (TDD)-underlay approach which is based on regular busy tones. Herein, stochastic geometry is used to model network deployments, while higherorder statistics through the cumulants concept is utilized to characterize the probability distribution of the aggregate interference at the tagged receiver. To conduct our studies, we consider a shadowed fading channel model incorporating log-normal shadowing and Nakagami-m fading. In addition, various network algorithms, such as power control and frequency (re)allocation, are included in the analytical framework. To evaluate the performance of the proposed solutions, we also derive closed-form expressions for the outage probability and average spectral efficiency with respect to the receiver of interest under various channel conditions and network configurations. Results show that the analytical framework matches well with numerical results obtained from Monte Carlo simulations, and that the coordination mechanisms substantially improve the performance of overlaid macrocell networks, while also benefiting small cells. In contrast to the uncoordinated Frequency Division Duplexing mode, the coordinated TDD-underlay solution shows a reduction in the outage probability, while the average spectral efficiency increases at high loads. Although more elaborated interference control techniques such as, downlink bitmap and distributed antennas systems become needed, when the density of uncoordinated small cells in the underlaid tier gets high<br>Tiivistelmä Tämä väitöskirja pyrkii arvioimaan autonomisia pakettikytkentäisiä järjestelmiä verkon näkökulmasta, kun resurssien ja verkon hallinta tapahtuu dynaamisesti ja adaptiivisesti. Tässä yhteydessä suunnitellaan QoS-tietoisia ratkaisuja resurssien jakamiseen ja hallintaan (esim. kanavan allokointi, kuorman hallinta, häiriön käsittely ja reititystekniikat) suuren skaalan langattomiin verkkoihin. Ehdotamme ja tutkimme hajautettuja koordinointimekanismeja monikanavien häiriöiden hallintaan monitasoisissa skenaarioissa, jotka koostuvat lyhyen kantaman soluista makrosoluissa. Peruste näille mekanismeille on resurssien opportunistinen uudelleenkäyttö tinkimättä käynnissä olevista lähetyksistä suuremmissa makrosoluissa, samalla kun QoS taataan molemman tason lähetyksissä. Pienentääkseen aiheutuvaa monikanavahäiriöitä, alemman tason pienet solut käyttävät hajautettua mekanismia, kuten esimerkiksi säännöllisiin varattu-ääniin perustuvaa Time Division Duplexing (TDD) - mekanismia, vähällä signaalien vaihdon määrällä. Stokastista geometriaa käytetään mallintamaan verkkoja, kun taas korkeamman tason tilastollista laskentaa kumulanttimenetelmän käsitteen kautta käytetään kuvaamaan kokonaishäiriön todennäköisyysjakaumaa merkityssä vastaanottimessa. Käsittelemme varjostuvaa ja häipyvää kanavamallia sisältäen log-normaalin varjostumisen ja Nakagamim häipymisen. Lisäksi sisällytämme analyyttiseen työhön monenlaisia verkkoalgoritmeja tehohallintaan ja taajuuden (uudelleen)allokointiin. Ehdotettujen ratkaisujen tehokkuuden arvioimiseksi johdamme myös suljetut muodot katkosten todennäköisyyksille ja keskimääräiselle spektrin käytön tehokkuudelle halutun vastaanottimen suhteen monissa kanavatiloissa ja verkon kokoonpanoissa. Tulokset osoittavat, että analyyttisen työn tulokset vastaavat hyvin Monte Carlo - simulaatioilla saatujen numeeristen tulosten kanssa ja että koordinointimekanismit parantavat makrosoluverkkojen tehokkuutta merkittävästi, samalla kun myös pienet solut hyötyvät. Toisin kuin koordinoimaton Frequency Division Duplexing -toimintatila, koordinoitu TDD-toimintatila pienentää katkosten todennäköisyyttä samalla kun keskimääräinen spektrin käytön tehokkuus kasvaa suurella kuormalla. Toisaalta kehittyneemät häiriönhallintatekniikat, kuten alalinkki bittikartta sekä hajautetut antennijärjestelmät, tulevat tarpeelliseksi, kun pienten koordinoimattomattomien solujen tiheys kasvaa alemmalla tasolla
38
Ayoubi, Tarek. "Distributed Data Management Supporting Healthcare Workflow from Patients’ Point of View." Thesis, Blekinge Tekniska Högskola, Avdelningen för för interaktion och systemdesign, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-6030.
Full textAbstract:
Patient’s mobility throughout his lifetime leaves a trial of information scattered in laboratories, clinical institutes, primary care units, and other hospitals. Hence, the medical history of a patient is valuable when subjected to special healthcare units or undergoes home-care/personal-care in elderly stage cases. Despite the rhetoric about patient-centred care, few attempts were made to measure and improve in this arena. In this thesis, we will describe and implement a high-level view of a Patient Centric information management, deploying at a preliminary stage, the use of Agent Technologies and Grid Computing. Thus, developing and proposing an infrastructure that allows us to monitor and survey the patient, from the doctor’s point of view, and investigate a Persona, from the patients’ side, that functions and collaborates among different medical information structures. The Persona will attempt to interconnect all the major agents (human and software), and realize a distributed grid info-structure that directly affect the patient, therefore, revealing an adequate and cost-effective solution for most critical information needs. The results comprehended in the literature survey, consolidating Healthcare Information Management with emerged intelligent Multi-Agent System Technologies (MAS) and Grid Computing; intends to provide a solid basis for further advancements and assessments in this field, by bridging and proposing a framework between the home-care sector and the flexible agent architecture throughout the healthcare domain.
39
Galland, Alban. "Distributed data management with access control : social Networks and Data of the Web." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00640725.
Full textAbstract:
The amount of information on the Web is spreading very rapidly. Users as well as companies bring data to the network and are willing to share with others. They quickly reach a situation where their information is hosted on many machines they own and on a large number of autonomous systems where they have accounts. Management of all this information is rapidly becoming beyond human expertise. We introduce WebdamExchange, a novel distributed knowledge-base model that includes logical statements for specifying information, access control, secrets, distribution, and knowledge about other peers. These statements can be communicated, replicated, queried, and updated, while keeping track of time and provenance. The resulting knowledge guides distributed data management. WebdamExchange model is based on WebdamLog, a new rule-based language for distributed data management that combines in a formal setting deductiverules as in Datalog with negation, (to specify intensional data) and active rules as in Datalog:: (for updates and communications). The model provides a novel setting with a strong emphasis on dynamicity and interactions(in a Web 2.0 style). Because the model is powerful, it provides a clean basis for the specification of complex distributed applications. Because it is simple, it provides a formal framework for studying many facets of the problem such as distribution, concurrency, and expressivity in the context of distributed autonomous peers. We also discuss an implementation of a proof-of-concept system that handles all the components of the knowledge base and experiments with a lighter system designed for smartphones. We believe that these contributions are a good foundation to overcome theproblems of Web data management, in particular with respect to access control.
40
Brown, Darren Jacob. "A NOVEL MESSAGE ROUTING LAYER FOR THE COMMUNICATION MANAGEMENT OF DISTRIBUTED EMBEDDED SYSTEMS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/41.
Full textAbstract:
Fault tolerant and distributed embedded systems are research areas that have the interest of such entities as NASA, the Department of Defense, and various other government agencies, corporations, and universities. Taking a system and designing it to work in the presence of faults is appealing to these entities as it inherently increases the reliability of the deployed system. There are a few different fault tolerant techniques that can be implemented in a system design to handle faults as they occur. One such technique is the reconfiguration of a portion of the system to a redundant resource. This is a difficult task to manage within a distributed embedded system because of the distributed, directly addressed data producer and consumer dependencies that exist in common network infrastructures. It is the goal of this thesis work to develop a novel message routing layer for the communication management of distributed embedded systems that reduces the complexity of this problem. The resulting product of this thesis provides a robust approach to the design, implementation, integration, and deployment of a distributed embedded system.
41
Palmskog, Karl. "Towards Correct and Efficient Program Execution in Decentralized Networks: Programming Languages, Semantics, and Resource Management." Doctoral thesis, KTH, Teoretisk datalogi, TCS, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152247.
Full textAbstract:
The Internet as of 2014 connects billions of devices, and is expected to connect tens of billions by 2020. To meet escalating requirements, networks must be scalable, easy to manage, and be able to efficiently execute programs and disseminate data. The prevailing use of centralized systems and control in, e.g., pools of computing resources, clouds, is problematic for scalability. A promising approach to management of large networks is decentralization, where independently acting network nodes communicate with their immediate neighbors to achieve desirable results at the global level. The research in this thesis addresses three distinct but interrelated problems in the context of cloud computing, networks, and programs running in clouds. First, we show how implementation correctness of active objects can be achieved in decentralized networks using location independent routing. Second, we investigate the feasibility of decentralized adaptive resource allocation for active objects in such networks, with promising results. Third, we automate an initial step of a process for converting programs with thread-based concurrency using shared memory to programs with message passing concurrency, which can then run efficiently in clouds. Specifically, starting from fragments of the distributed object modeling language ABS, we give network-oblivious descriptions of runtime behavior of programs, where the global state is a flat collection of objects and method calls. We then provide network-aware semantics, that place objects on network nodes connected point-to-point by asynchronous message passing channels. By relying on location independent routing, which maps object identifiers to next-hop neighbors at each node, inter-object messages can be delivered, regardless of object mobility among nodes. We establish that network-oblivious and network-aware behavior in static networks correspond in the sense of contextual equivalence. Using a network protocol reminiscent of a two-phase commit for controlled node shutdown, we extend the approach to dynamic networks without failures. We investigate node-local procedures for object migration to meet requirements on balanced allocations of objects to nodes, that also attempt to minimize exchange of object-related messages between nodes. By relying on coin-flips biased on local and neighbor load to decide on migration, and heuristics to capture object communication patterns, we show that balanced allocations can be achieved that make headway towards minimizing communication and latency. Our approach to execution of object-oriented programs in networks relies on message-passing concurrency. Mainstream programming languages generally use thread-based concurrency, which relies on control-centric primitives, such as locks, for synchronization. We present an algorithm for dynamic probabilistic inference of annotations for data-centric synchronization in threaded programs. By making collections of variables in classes accessed atomically explicit, these annotations can in turn suggest objects suitable for encapsulation as a unit of message-passing concurrency.<br>2014 års Internet sammankopplar miljarder enheter, och förväntas sammankoppla tiotals miljarder år 2020. För att möta eskalerande krav måste nätverk vara skalbara, enkla att underhålla, och effektivt exekvera program och disseminera data. Den nuvarande användningen av centraliserade system och kontrollmekanismer, t ex i pooler av beräkningsresurser, moln, är problematisk för skalbarhet. Ett lovande angreppssätt för att hantera storskaliga nätverk är decentralisering, där noder som agerar oberoende av varandra genom kommunikation med sina omedelbara grannar åstadkommer gynnsamma resultat på den globala nivån. Forskningen i den här avhandlingen addresserar tre distinkta men relaterade problem i kontexten av molnsystem, nätverk och program som körs i moln. För det första visar vi hur implementationskorrekthet för aktiva objekt kan åstadkommas i decentraliserade nätverk med hjälp av platsoberoende routning. För det andra undersöker vi genomförbarheten i decentraliserad adaptiv resursallokering för aktiva objekt i sådana nätverk, med lovande resultat. För det tredje automatiserar vi ett initialt steg i en process för att konvertera program med trådbaserad samtidighet och delat minne till program med meddelandebaserad samtidighet, som då kan köras effektivt i moln. Mer specifikt ger vi, med utgångspunkt i fragment av modelleringsspråket ABS baserat på distribuerade objekt, nätverksomedvetna beskrivningar av körningstidsbeteende för program där det globala tillståndet är en platt samling av objekt och metodanrop. Vi ger därefter nätverksmedvetna semantiker, där objekt placeras på nätverksnoder sammankopplade från punkt till punkt av asynkrona kanaler för meddelandetransmission. Genom att vid varje nod använda platsoberoende routning, som associerar objektidentifierare med grannoder som är nästa hopp, kan meddelanden mellan objekt levereras oavsett hur objekt rör sig mellan noder. Vi etablerar att nätverksomedvetet och nätverksmedvetet beteende i statiska nätverk stämmer överens enligt kontextuell ekvivalens. Genom att använda ett nätverksprotokoll som påminner om en tvåstegsförpliktelse, utökar vi vår ansats till felfria dynamiska nätverk. Vi undersöker nodlokala procedurer för objektmigration för att möta krav på balanserade allokeringar av objekt till noder, som också försöker minimera utbyte av objektrelaterade meddelanden mellan noder. Genom att använda oss av slantsinglingar viktade efter lokal last och grannars last för att besluta om migration, och tumregler för att fånga kommunikationsmönster mellan objekt, visar vi att balanserade allokeringar, som gör framsteg mot att minimera kommunikation och tidsfördröjning, kan uppnås. Vår ansats för exekvering av objektorienterade program i nätverk använder meddelandebaserad samtidighet. Vanligt förekommande programspråk använder sig generellt av trådbaserad samtidighet, som kräver kontrollcentrerade mekanismer, som lås, för synkronisering. Vi presenterar en algoritm som med dynamisk probabilistisk analys härleder annoteringar för datacentrerad synkronisering för trådade program. Genom att göra samlingar av variabler i klasser som läses och skrivs atomiskt explicita, kan sådana annoteringar antyda vilka objekt som är lämpliga att kapsla in som en enhet i meddelandebaserad samtidighet.<br><p>QC 20140929</p>
42
Fila, Maciej. "Modelling, evaluation and demonstration of novel active voltage control schemes to accomodate distributed generation in distribution networks." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/5516.
Full textAbstract:
Voltage control in distribution networks is becoming more challenging due to the growing amount of distributed generation that is being connected to the distribution networks in addition to increasing load. The output of the distributed generation can radically change power flows and voltage profiles in distribution networks, creating conditions that adversely affect the performance of automatic voltage control schemes and in addition cause unacceptable voltage rise. On the other hand, inherent limitations and current operational policies of AVC schemes very often restrict the output of DG or even prevent its connection. This thesis investigates and analyses voltage control in terms of the shift from passive to active distribution networks. The thesis also reviews the performance of AVC schemes under varying load and generation output conditions, investigates effective utilisation of distribution network assets and methods to accommodate active voltage control schemes into existing infrastructure. A range of active voltage control and management schemes based on coordinated voltage control is presented and assessed. These schemes can be used to improve the voltage profile in distribution networks and increase their ability to accommodate distributed generation. The functionality of each scheme is assessed based on a number of factors such as the ability of the scheme to increase network capacity, reliability and accuracy. Simulation software to accurately evaluate the performance of an active voltage control scheme in a particular distribution network scenario is essential before the scheme can be deployed. Formal assessment of advanced AVC models and SuperTAPP n+ functionality is performed using simulation software as developed and presented in this thesis. The accuracy of the software results and performance of the SuperTAPP n+ scheme is validated based on network trials carried out in EDF Energy Networks.
43
Kourtellis, Nicolas. "On the Design of Socially-Aware Distributed Systems." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4107.
Full textAbstract:
Social media services and applications enable billions of users to share an unprecedented amount of social information, which is further augmented by location and collocation information from mobile phones, and can be aggregated to provide an accurate digital representation of the social world. This dissertation argues that extracted social knowledge from this wealth of information can be embedded in the design of novel distributed, socially-aware applications and services, consequently improving system response time, availability and resilience to attacks, and reducing system overhead. To support this thesis, two research avenues are explored.
First, this dissertation presents Prometheus, a socially-aware peer-to-peer service that collects social information from multiple sources, maintains it in a decentralized fashion on user-contributed nodes, and exposes it to applications through an interface that implements non-trivial social inferences. The system's socially-aware design leads to multiple system improvements: 1) it increases service availability by allowing users to manage their social information via socially-trusted peers, 2) it improves social inference performance and reduces message overhead by exploiting naturally-formed social groups, and 3) it reduces the opportunity of attackers to influence application requests. These performance improvements are assessed via simulations and a prototype deployment on a local cluster and on a worldwide testbed (PlanetLab) under emulated application workloads.
Second, this dissertation defines the projection graph, the result of decentralizing a social graph onto a peer-to-peer system such as Prometheus, and studies the system's network properties and how they can be used to design more efficient socially-aware distributed applications and services. In particular: 1) it analytically formulates the relation between centrality metrics such as degree centrality, node betweenness centrality, and edge betweenness centrality in the social graph and in the emerging projection graph, 2) it experimentally demonstrates on real networks that for small groups of users mapped on peers, there is high association of social and projection graph properties, 3) it shows how these properties of the (dynamic) projection graph can be accurately inferred from the properties of the (slower changing) social graph, and 4) it demonstrates with two search application scenarios the usability of the projection graph in designing social search applications and unstructured P2P overlays.
These research results lead to the formulation of lessons applicable to the design of socially-aware applications and distributed systems for improved application performance such as social search, data dissemination, data placement and caching, as well as for reduced system communication overhead and increased system resilience to attacks.
44
Melchiors, Cristina. "Gerenciamento de redes fortemente distribuído utilizando a tecnologia P2P." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/34746.
Full textAbstract:
O gerenciamento de redes é realizado seguindo diversos modelos, baseados em diferentes paradigmas. Os paradigmas tradicionais de gerenciamento compreendem o paradigma centralizado e o paradigma hierárquico fracamente distribuído. Tais paradigmas, contudo, apresentam limitações para o gerenciamento de diversas redes atuais, em virtude de fatores como o aumento em tamanho, em complexidade e em heterogeneidade destas redes. Em adição a estes fatores, existem atualmente contextos de rede que, por apresentarem certas peculiaridades, não podem ser gerenciados de modo apropriado por tais modelos. Estas limitações e requisitos diferenciados encontrados nas redes atuais trazem a necessidade do emprego de modelos de gerenciamento inovadores, baseados nos paradigmas fortemente distribuídos. Neste contexto, uma tecnologia que se mostra promissora para o desenvolvimento de um modelo de gerenciamento com tais características é a tecnologia peer-to-peer (P2P). Esta Tese versa sobre estes tópicos. Discute, como primeiro objetivo, as limitações dos modelos tradicionais para o gerenciamento de contextos modernos de rede, isto é, contextos de redes atuais que possuem particularidades distintas e, com isto, demandam requisitos de gerenciamento específicos, não identificados nas redes tradicionais. Define e investiga, então, como segundo objetivo, um modelo de gerenciamento fortemente distribuído baseado na tecnologia P2P. Este modelo visualiza a rede P2P como uma infra-estrutura que provê suporte para que as operações de gerenciamento sejam desempenhadas com forte distribuição. Por fim, como terceiro objetivo, analisa como as soluções de gerenciamento para redes atuais baseadas neste modelo podem ser classificadas segundo os paradigmas de gerenciamento das principais taxonomias propostas na literatura. Tal análise proporciona a identificação das limitações destas taxonomias para a classificação das soluções de gerenciamento requeridas para os contextos de redes atuais e deu origem à definição de uma taxonomia para soluções de gerenciamento que destaca as características e os requisitos demandados dos modelos de gerenciamento modernos.<br>Network management is carried out following several models, based on different paradigms. Traditional management paradigms consist of centralized and weakly distributed hierarchical ones. However, such paradigms present limitations to be applied to the management of several today networks. This occurs because of some issues such as the grown in size, complexity and heterogeneity of such networks. Additionally, nowadays, there are network contexts that can not be appropriately managed by such models because of some context peculiarities. Those today’s networks drawbacks and requirements demand the employment of innovative models, based on strongly distributed paradigms. A technology that seems promising in addressing such needs is peer-to-peer (P2P). This Thesis discusses about those topics. As its first objective, the Thesis discusses traditional models drawbacks to the management of modern network contexts, this is, current network contexts that have some different peculiarities and, because of them, demand specific management requirements not existent in traditional networks. As its second objective, the Thesis defines and investigates a strongly distributed management model based on P2P technology. Such model looks at P2P network as an infrastructure that can be used as support to management operations be accomplished in a strongly distributed way. Finally, as its third objective, the Thesis analyses how the management solutions based on such model can be classified according the management paradigms of the main literature taxonomies. Such analysis provides the identification of taxonomies limitations to the classification of management solutions required by today’s network contexts. It has originated the definition of a management solution taxonomy that emphasizes the features and requirements demanded of modern management models.
45
Gensollen, Nicolas. "Modeling and optimizing a distributed power network : a complex system approach of the "prosumer" management in the smart grid." Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0019/document.
Full textAbstract:
Cette thèse est consacrée à l'étude d’agents appelés prosumers parce qu’ils peuvent, à partir d’énergies renouvelables, à la fois produire et consommer de l’électricité. Si leurs productions excèdent leurs propres besoins, ceux-ci cherchent à vendre leur surplus sur des marchés de l’électricité. Nous proposons de modéliser ces prosumers à partir de données météorologiques, ce qui nous a permit de mettre en évidence des corrélations spatio-temporelles non triviales, d'une grande importance pour les agrégateurs qui forment des portefeuilles d’équipements afin de vendre des services à l'opérateur du réseau. Comme un agrégateur est lié par un contrat avec l'opérateur, il peut faire l'objet de sanctions s’il ne remplit pas son rôle. Nous montrons que ces corrélations impactent la stabilité des agrégats, et donc le risque encouru par les agrégateurs. Nous proposons un algorithme minimisant le risque d'un ensemble d’agrégations, tout en maximisant le gain attendu. La mise en place de dispositifs de stockage dans un réseau où les générateurs et les charges sont dynamiques et stochastiques est complexe. Nous proposons de répondre à cette question grâce à la théorie du contrôle. Nous modélisons le système électrique par un réseau d'oscillateurs couplés, dont la dynamique des angles de phase est une approximation de la dynamique réelle du système. Le but est de trouver le sous-ensemble des nœuds du graphe qui, lors d'une perturbation du système, permet le retour à l'équilibre si les bons signaux sont injectés, et ceci avec une énergie minimum. Nous proposons un algorithme pour trouver un placement proche de l'optimum permettant de minimiser l'énergie moyenne de contrôle<br>This thesis is devoted to the study of agents called prosumers because they can, from renewable, both produce and consume electricity. If their production exceeds their own needs, they are looking to sell their surplus on electricity markets. We propose to model these prosumers from meteorological data, which has allowed us to highlight non trivial spatial and temporal correlations. This is of great importance for aggregators that form portfolios of equipments to sell services to the network operator. As an aggregator is bound by a contract with the operator, it can be subject to penalties if it does not fulfill its role. We show that these correlations impact the stability of aggregates, and therefore the risk taken by the aggregators. We propose an algorithm minimizing the risk of the aggregations, while maximizing the expected gain. The placement of storage devices in a network where generators and loads are stochastic and not fixed is complex. We propose to answer this question with control theory. We model the electrical system as a network of coupled oscillators, whose phase angles dynamics is an approximation of the actual dynamics of the system. The goal is to find the subset of nodes in the graph that, during a disturbance of the system, allows returning to equilibrium if the right signals are injected and this with a minimum energy. We propose an algorithm to find a near optimal placement to minimize the average energy control
46
Vilanova, Felipe Jung. "Uma ferramenta peer-to-peer para gerenciamento cooperativo de redes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/8496.
Full textAbstract:
Com o crescimento em número e diversidade dos componentes das redes de computadores, surge a necessidade de buscar uma maneira consistente de realizar seu gerenciamento para, com isso, manter toda sua estrutura funcionando de forma suave e atendendo às necessidades de seus usuários e às expectativas de seus administradores. Em aspectos gerais, as abordagens centralizadas têm se mostrado inadequadas para o gerenciamento de redes de computadores com um grande número de nós ou com grande diversidade de dispositivos. A necessidade de distribuição da gerência torna-se, assim, evidente, onde vários operadores administram cooperativamente a rede, cada um sendo responsável por um segmento da mesma, mas que precisam poder inspecionar os demais segmentos para poder resolver problemas distintos. Por isso a necessidade de um sistema de suporte ao gerenciamento cooperativo, que forneça suporte à interação dos administradores, independente de tempo e da localização dos participantes. É esse sistema que determinará como os administradores vão se comunicar, distribuir responsabilidades, compartilhar informações, e utilizar as ferramentas disponíveis. Nesse contexto, esta dissertação de mestrando apresenta a proposta de um ambiente de gerenciamento distribuído e cooperativo, baseado na tecnologia P2P. Esse ambiente oferece quatro serviços: compartilhamento de arquivos de configuração de dispositivos, compartilhamento de registros de dispositivos, configuração de dispositivos e solicitação de reserva de banda. A partir da proposta do ambiente foi implementada em Java, utilizando a plataforma de desenvolvimento JXTA, uma aplicação para a realização de testes, com o objetivo de confirmar a possibilidade de utilização da aplicação para realizar o gerenciamento de redes. Os parâmetros observados nas avaliações de desempenho foram o tráfego gerado e o tempo de resposta. Os resultados dos testes comprovaram a possibilidade da utilização de sistemas P2P para facilitar o gerenciamento cooperativo de redes e foram bastante satisfatórios com relação aos parâmetros avaliados.<br>With the increasing number and diversity of components of the computer networks, comes the necessity to find a consistent way to manage modern networks. This is required in order to keep all network infrastructures working in a proper and smooth way, while taking care of to the network users’ necessities and filling the network administrators’ expectations. In general aspects, the centralized management approaches are inadequate for the management of networks with a great number of nodes or great diversity of devices. The necessity of a distributed management thus becomes evident. In such distributed management, a group of administrators manages a single network in a cooperative fashion, each administrator being responsible for a segment of the managed network but at the same time being able to inspect other remote segments in order to solve non-overlapping problems. That is the motivation for having management systems with proper cooperative management support that allows interactions among administrators independent of time and location. Such a system will determine how administrators will communicate to delegate responsibilities, share information, and use the available tools. In this context, this dissertation presents the proposal of a distributed and cooperative management environment based on P2P technology. This environment offers four services: sharing of device configuration files, sharing of registered devices, configuration of devices, and bandwidth reservation. Based on the proposed environment, a Java application, using the JXTA development platform, has been implemented. This application allowed us to test and confirm the possibility of using P2P technologies for network management. In addition, the performance of the implemented solution has been measured considering the generated management traffic and response time. The results from the evaluation tests had proven the possibility of the use of P2P systems to facilitate the cooperative network management and had been sufficiently satisfactory in relation to the evaluated parameters.
47
Alnaser, Sahban Wa'el Saeed. "Control of distributed generation and storage : operation and planning perspectives." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/control-of-distributed-generation-and-storage-operation-and-planning-perspectives(a937e071-4e6b-4a07-a196-031c3b23655f).html.
Full textAbstract:
Transition towards low-carbon energy systems requires an increase in the volume of renewable Distributed Generation (DG), particularly wind and photovoltaic, connected to distribution networks. To facilitate the connection of renewable DG without the need for expensive and time-consuming network reinforcements, distribution networks should move from passive to active methods of operation, whereby technical network constraints are actively managed in real time. This requires the deployment of control solutions that manage network constraints and, crucially, ensure adequate levels of energy curtailment from DG plants by using other controllable elements to solve network issues rather than resorting to generation curtailment only. This thesis proposes a deterministic distribution Network Management System (NMS) to facilitate the connections of renewable DG plants (specifically wind) by actively managing network voltages and congestion in real time through the optimal control of on-load tap changers (OLTCs), DG power factor and, then, generation curtailment as a last resort. The set points for the controllable elements are found using an AC Optimal Power Flow (OPF). The proposed NMS considers the realistic modelling of control by adopting one-minute resolution time-series data. To decrease the volumes of control actions from DG plants and OLTCs, the proposed approach departs from multi-second control cycles to multi-minute control cycles. To achieve this, the decision-making algorithm is further improved into a risk-based one to handle the uncertainties in wind power throughout the multi-minute control cycles. The performance of the deterministic and the risk-based NMS are compared using a 33 kV UK distribution network for different control cycles. The results show that the risk-based approach can effectively manage network constraints better than the deterministic approach, particularly for multi-minute control cycles, reducing also the number of control actions but at the expense of higher levels of curtailment. This thesis also proposes energy storage sizing framework to find the minimum power rating and energy capacity of multiple storage facilities to reduce curtailment from DG plants. A two-stage iterative process is adopted in this framework. The first stage uses a multi-period AC OPF across the studied horizon to obtain initial storage sizes considering hourly wind and load profiles. The second stage adopts a high granularity minute-by-minute control driven by a mono-period bi-level AC OPF to tune the first-stage storage sizes according to the actual curtailment. The application of the proposed planning framework to a 33 kV UK distribution network demonstrates the importance of embedding real-time control aspects into the planning framework so as to accurately size storage facilities. By using reactive power capabilities of storage facilities it is possible to reduce storage sizes. The combined active management of OLTCs and power factor of DG plants resulted in the most significant benefits in terms of the required storage sizes.
48
Qureshi, Basit I. "Trust Management for P2P application in Delay Tolerant Mobile Ad-hoc Networks. An Investigation into the development of a Trust Management Framework for Peer to Peer File Sharing Applications in Delay Tolerant Disconnected Mobile Ad-hoc Networks." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5185.
Full textAbstract:
Security is essential to communication between entities in the internet. Delay tolerant and disconnected Mobile Ad Hoc Networks (MANET) are a class of networks characterized by high end-to-end path latency and frequent end-to-end disconnections and are often termed as challenged networks. In these networks nodes are sparsely populated and without the existence of a central server, acquiring global information is difficult and impractical if not impossible and therefore traditional security schemes proposed for MANETs cannot be applied. This thesis reports trust management schemes for peer to peer (P2P) application in delay tolerant disconnected MANETs. Properties of a profile based file sharing application are analyzed and a framework for structured P2P overlay over delay tolerant disconnected MANETs is proposed. The framework is implemented and tested on J2ME based smart phones using Bluetooth communication protocol. A light weight Content Driven Data Propagation Protocol (CDDPP) for content based data delivery in MANETs is presented. The CDDPP implements a user profile based content driven P2P file sharing application in disconnected MANETs. The CDDPP protocol is further enhanced by proposing an adaptive opportunistic multihop content based routing protocol (ORP). ORP protocol considers the store-carry-forward paradigm for multi-hop packet delivery in delay tolerant MANETs and allows multi-casting to selected number of nodes. Performance of ORP is compared with a similar autonomous gossiping (A/G) protocol using simulations. This work also presents a framework for trust management based on dynamicity aware graph re-labelling system (DA-GRS) for trust management in mobile P2P applications. The DA-GRS uses a distributed algorithm to identify trustworthy nodes and generate trustable groups while isolating misleading or untrustworthy nodes. Several simulations in various environment settings show the effectiveness of the proposed framework in creating trust based communities. This work also extends the FIRE distributed trust model for MANET applications by incorporating witness based interactions for acquiring trust ratings. A witness graph building mechanism in FIRE+ is provided with several trust building policies to identify malicious nodes and detect collusive behaviour in nodes. This technique not only allows trust computation based on witness trust ratings but also provides protection against a collusion attack. Finally, M-trust, a light weight trust management scheme based on FIRE+ trust model is presented.
49
Vilà, Talleda Pere. "Dynamic management and restoration of virtual paths in broadband networks based on distributed software agents." Doctoral thesis, Universitat de Girona, 2004. http://hdl.handle.net/10803/7726.
Full textAbstract:
La gestió de xarxes és un camp molt ampli i inclou molts aspectes diferents. Aquesta tesi doctoral està centrada en la gestió dels recursos en les xarxes de banda ampla que disposin de mecanismes per fer reserves de recursos, com per exemple Asynchronous Transfer Mode (ATM) o Multi-Protocol Label Switching (MPLS). Es poden establir xarxes lògiques utilitzant els Virtual Paths (VP) d'ATM o els Label Switched Paths (LSP) de MPLS, als que anomenem genèricament camins lògics. Els usuaris de la xarxa utilitzen doncs aquests camins lògics, que poden tenir recursos assignats, per establir les seves comunicacions. A més, els camins lògics són molt flexibles i les seves característiques es poden canviar dinàmicament. Aquest treball, se centra, en particular, en la gestió dinàmica d'aquesta xarxa lògica per tal de maximitzar-ne el rendiment i adaptar-la a les connexions ofertes.<br/>En aquest escenari, hi ha diversos mecanismes que poden afectar i modificar les característiques dels camins lògics (ample de banda, ruta, etc.). Aquests mecanismes inclouen els de balanceig de la càrrega (reassignació d'ample de banda i reencaminament) i els de restauració de fallades (ús de camins lògics de backup). Aquests dos mecanismes poden modificar la xarxa lògica i gestionar els recursos (ample de banda) dels enllaços físics. Per tant, existeix la necessitat de coordinar aquests mecanismes per evitar possibles interferències. La gestió de recursos convencional que fa ús de la xarxa lògica, recalcula periòdicament (per exemple cada hora o cada dia) tota la xarxa lògica d'una forma centralitzada. Això introdueix el problema que els reajustaments de la xarxa lògica no es realitzen en el moment en què realment hi ha problemes. D'altra banda també introdueix la necessitat de mantenir una visió centralitzada de tota la xarxa. <br/>En aquesta tesi, es proposa una arquitectura distribuïda basada en un sistema multi agent. L'objectiu principal d'aquesta arquitectura és realitzar de forma conjunta i coordinada la gestió de recursos a nivell de xarxa lògica, integrant els mecanismes de reajustament d'ample de banda amb els mecanismes de restauració preplanejada, inclosa la gestió de l'ample de banda reservada per a la restauració. Es proposa que aquesta gestió es porti a terme d'una forma contínua, no periòdica, actuant quan es detecta el problema (quan un camí lògic està congestionat, o sigui, quan està rebutjant peticions de connexió dels usuaris perquè està saturat) i d'una forma completament distribuïda, o sigui, sense mantenir una visió global de la xarxa. Així doncs, l'arquitectura proposada realitza petits rearranjaments a la xarxa lògica adaptant-la d'una forma contínua a la demanda dels usuaris. L'arquitectura proposada també té en consideració altres objectius com l'escalabilitat, la modularitat, la robustesa, la flexibilitat i la simplicitat.<br/>El sistema multi agent proposat està estructurat en dues capes d'agents: els agents de monitorització (M) i els de rendiment (P). Aquests agents estan situats en els diferents nodes de la xarxa: hi ha un agent P i diversos agents M a cada node; aquests últims subordinats als P. Per tant l'arquitectura proposada es pot veure com una jerarquia d'agents. Cada agent és responsable de monitoritzar i controlar els recursos als que està assignat. <br/>S'han realitzat diferents experiments utilitzant un simulador distribuït a nivell de connexió proposat per nosaltres mateixos. Els resultats mostren que l'arquitectura proposada és capaç de realitzar les tasques assignades de detecció de la congestió, reassignació dinàmica d'ample de banda i reencaminament d'una forma coordinada amb els mecanismes de restauració preplanejada i gestió de l'ample de banda reservat per la restauració. L'arquitectura distribuïda ofereix una escalabilitat i robustesa acceptables gràcies a la seva flexibilitat i modularitat.<br>Network management is a wide field including many different topics. This thesis focuses on resource management of broadband networks that have the mechanisms for performing resource reservation, such as Asynchronous Transfer Mode (ATM) or Multi-Protocol Label Switching (MPLS). Logical networks can be established by using Virtual Paths (VP) in ATM or Label Switched Paths (LSP) in MPLS, which we call generically Logical Paths (LP). The network users then use these LPs, which can have pre-reserved resources, to establish their communications. Moreover, LPs are very flexible and their characteristics can be dynamically changed. This work focuses, in particular, on the dynamic management of these logical paths in order to maximise the network performance by adapting the logical network to the offered connections.<br/>In this scenario, there are several mechanisms that can affect and modify certain features of the LPs (bandwidth, route, etc.). They include load balancing mechanisms (bandwidth reallocation and re-routing) and fault restoration (utilisation of backup LPs). These two mechanisms can modify the logical network and manage the resources (bandwidth) of the physical links. Therefore, due to possible interferences, there is a need to co-ordinate these mechanisms. Conventional resource management, using a logical network, performs a centralised recalculation of the whole logical network periodically (e.g. every hour / day). This brings the problem that the logical network readjustments do not happen when a problem occurs. Moreover, there is a need of maintaining a centralised network overview. <br/>In this thesis, a distributed architecture, based on a Multi-Agent System (MAS), is proposed. The main objective of this architecture is to perform joint resource management at a logical network level, integrating the bandwidth reallocation and LP re-routing with pre-planned restoration and spare bandwidth management. This is performed continuously, not periodically, when a problem is detected (an LP is congested, i.e. it is rejecting new user connections because it is already saturated with user connections) in a completely distributed way, i.e. without any central network overview. Therefore, the proposed architecture performs small rearrangements in the logical network and thus it is continuously being adapted to the user demands. The proposed architecture also considers other objectives, such as scalability, modularity, robustness, simplicity and flexibility. <br/>The proposed MAS is structured in two layers of agents: The network Monitoring (M) agents and the Performance (P) agents. All these agents are situated at different network nodes, where the computing facilities are. There is one P agent and several M agents on every node. The M agents are subordinated to the P agents, therefore the proposed architecture can be seen as a hierarchy of agents. Each agent is responsible for monitoring and controlling the resources they are assigned to. <br/>We have performed several experiments, using a connection level distributed simulator of our own design. The results show that our architecture is capable of performing the assigned tasks of detecting congestion, dynamic bandwidth reallocation and re-routing in a co-ordinated way with the pre-planned restoration and the spare capacity management. The distributed architecture offers a suitable scalability and robustness due to its flexibility and modularity.
50
Polina, Everton Rafael. "Uso de gerenciamento por delegação para controle e administração de no-breaks." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/13206.
Full textAbstract:
Atualmente há grande investimento por parte das empresas em sistemas que não podem parar e, conseqüentemente, em sistemas de gerenciamento para perceber a ocorrência de falhas ou prevê-las e evitar que elas aconteçam. Para amenizar os efeitos de falhas no fornecimento de energia elétrica, que são ainda comuns no país e em boa parte do mundo, são utilizados os no-breaks. Esses equipamentos são projetados para garantir o fornecimento de energia por um tempo definido e limitado nos momentos em que a concessionária de energia elétrica interrompe esse fornecimento. O objetivo principal do presente trabalho é investigar uma solução de gerenciamento de no-breaks que possui como grande diferencial a utilização do paradigma de gerenciamento distribuído por delegação, com o uso do protocolo SNMP, apresentando as vantagens desse paradigma. Para a distribuição de tarefas, a solução utiliza a MIB Script e uma implementação deste padrão (JASMIN – Java Script MIB Implementation) de forma que toda a interatividade com a ferramenta e a automatização dos processos que compõem a solução foi implementada com o uso das ferramentas livres Apache e PHP. O trabalho apresenta uma breve descrição sobre o funcionamento dos no-breaks e destaca a UPS-MIB, MIB padrão para gerenciamento desses equipamentos, além de objetos importantes disponibilizados em outras MIBs proprietárias utilizadas para o gerenciamento de no-breaks. Além disso, o presente estudo sugere o uso de ferramentas para que o sistema de gerência seja responsável pelas estações alimentadas pelos nobreaks, ou seja, quando identificado que está próximo o momento do no-break não conseguir mais alimentar a carga, deve-se desligar a carga com segurança para que não ocorra uma perda de dados maior nem haja danos em componentes. Nota-se que o gerenciamento utilizado neste trabalho, realizado através da ferramenta desenvolvida, facilita a detecção de falhas no sistema de fornecimento de energia, de modo a interagir satisfatoriamente com no-breaks para verificar condições da rede elétrica e tomar decisões pró-ativas com o intuito de manter uma rede de computadores em funcionamento, sem que haja percalços por problemas de falta de energia.<br>Nowadays most companies are investing in non-stop systems, which leads to investments in management systems to know when a fault occurs or to foresee and avoid them. To reduce the effects of power supply faults (which are common in Brazil and in other parts of the world), people use UPS systems. These equipments are designed to guarantee the power supply for a pre-defined limited time, just in case the power company interrupts the supply. The main goal of this work is to present the implementation of a management application for UPS systems, which has the differential of using the management-bydelegation paradigm, based on SNMP, showing the advantages of this paradigm. The application uses Script MIB and an implementation of this standard (JASMIN - Java Script MIB Implementation) for task distribution, in such a way that all the tool interactivity and process automation was done using the free tools Apache and PHP. The work also presents a brief description about the UPS functioning, and shows UPS-MIB, the standard MIB for UPS management. Additionally the work presents some important objects available in some custom MIBs that are used for UPS management too. This study suggests the use of a set of tools to make the management system responsible for the workstations plugged on the UPS, which means that when the UPS is about to be unable to maintain the load, it should be turned off safely to avoid data losses or hardware faults. One can note that the management done in this work through the developed tool makes easy the fault detection in the power supply system. This leads to a good interaction with the UPS to verify the conditions of the power network in order to take decisions to maintain the computer network running safely.