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1
Guleria, Pratiyush. "Data Access Layer: A Programming Paradigm on Cloud". INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 11, n. 3 (15 ottobre 2013): 2341–45. http://dx.doi.org/10.24297/ijct.v11i3.1164.
Testo completoAbstract (sommario):
Database is important for any application and critical part of private and public cloud platforms. For compatibility with cloud computing we can follow architectures like three tier architecture in .Net Technologies such that database layer should be separate from user and business logic layers. There are some other issues like following ACID properties in databases, providing dynamic scalability by using Shared-disk Architecture and efficient multi-tenancy, elastic scalability, and database privacy.
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Chandnani, Manali, Mukesh Kumar Khandelwal e Meeta Sharma. "A Survey on Synchronization Approach in MAC Layer Protocols". International Journal of Business Data Communications and Networking 13, n. 1 (gennaio 2017): 9–27. http://dx.doi.org/10.4018/ijbdcn.2017010102.
Testo completoAbstract (sommario):
The Open Systems Interconnection (OSI) model describes the layered approach for communication between two networked systems. The Data link layer of OSI model consists of a sub layer known as MAC layer for achieving coordination among the communicating nodes to access the shared channel. This channel is shared between multiple nodes in a communication network and the packets transmitted at same time by different nodes collide with each other. This situation leads to loss of data and bandwidth gets wasted. To avoid this situation, MAC layer supports various protocols: TDMA, ALOHA, CSMA/CD, CSMA/CA and many hybrid techniques which employ their own criteria of synchronization for minimizing the collisions. In this paper the authors discuss about the MAC layer and the multiple access protocols which it supports for achieving synchronization among the nodes in the channel.
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Hudák, Marián, Štefan Korečko e Branislav Sobota. "LIRKIS Global Collaborative Virtual Environments: Current State and Utilization Perspective". Open Computer Science 11, n. 1 (17 dicembre 2020): 99–106. http://dx.doi.org/10.1515/comp-2020-0124.
Testo completoAbstract (sommario):
AbstractRecent advances in the field of web technologies, including the increasing support of virtual reality hardware, have allowed for shared virtual environments, reachable by just entering a URL in a browser. One contemporary solution that provides such a shared virtual reality is LIRKIS Global Collaborative Virtual Environments (LIRKIS G-CVE). It is a web-based software system, built on top of the A-Frame and Networked-Aframe frameworks. This paper describes LIRKIS G-CVE and introduces its two original components. The first one is the Smart-Client Interface, which turns smart devices, such as smartphones and tablets, into input devices. The advantage of this component over the standard way of user input is demonstrated by a series of experiments. The second component is the Enhanced Client Access layer, which provides access to positions and orientations of clients that share a virtual environment. The layer also stores a history of connected clients and provides limited control over the clients. The paper also outlines an ongoing experiment aimed at an evaluation of LIRKIS G-CVE in the area of virtual prototype testing.
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Scott, Rachel E., e Gail Barton. "Promoting Interlibrary Loan in the Traditional Catalog and Discovery Layer: Two Pilot Projects". Library Resources & Technical Services 62, n. 2 (4 aprile 2018): 74. http://dx.doi.org/10.5860/lrts.62n2.74.
Testo completoAbstract (sommario):
This paper describes two projects that promote interlibrary loan (ILL) in both traditional online public access catalogs and discovery settings to address user frustrations with gaps in the collection. By creating and inserting OpenURL links into bibliographic records for titles held exclusively by external institutions, the authors leveraged the discovery capabilities of their shared catalog and promoted ILL as an alternative means of access. The second project targeted the overwhelming amount of content indexed in the library’s discovery layer that was not locally available. To more directly translate discovery into access, the authors worked with EBSCO to create and enable ILL CustomLinks for this content indexed by EBSCO Discovery Service and not available to their users. This paper presents ILL data to investigate whether these projects are changing the ways our users find and access content not held locally.
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Wang, Xiu Juan, Xiao Bing Li, Yu Tang Chen, Meng Cheng, Zhong Xin Zhang e Xiu Yun Cai. "Design and Implementation of Real-Time Database in Embedded Configuration Software". Applied Mechanics and Materials 411-414 (settembre 2013): 370–76. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.370.
Testo completoAbstract (sommario):
This paper mainly introduces the design idea of real-time database in embedded configuration software. According to the characteristics of real-time database, this paper using three layer storage structures which consist of shared memory, file system and general database. It improves the access efficiency of real-time database and data reliability in a timely manner.
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Qi, Xin, Kun Wang, AnPeng Huang, Haifeng Hu e Guangjie Han. "MAC Protocol in Wireless Body Area Network for Mobile Health: A Survey and an Architecture Design". International Journal of Distributed Sensor Networks 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/289404.
Testo completoAbstract (sommario):
Wireless body area networks (WBANs) have become a leading solution in mobile health (mHealth). Typically, a WBAN consists of in-body or around-body sensor nodes for collecting data of physiological feature. For a WBAN to provide high throughput and low delay in an energy-efficient way, designing an efficient medium access control (MAC) protocol is of paramount importance because the MAC layer coordinates nodes’ access to the shared wireless medium. To show the difference of MAC protocols between Energy-Harvesting wireless body area networks (EH-WBANs) and battery powered WBANs (BT-WBANs), this paper surveys the latest progresses in energy harvesting techniques and WBAN MAC protocol designs. Furthermore, a novel energy utility architecture is designed to enable sensor node lifetime operation in an EH-WBAN.
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Bhavadharini, R. M., S. Karthik, N. Karthikeyan e Anand Paul. "Wireless Networking Performance in IoT Using Adaptive Contention Window". Wireless Communications and Mobile Computing 2018 (3 luglio 2018): 1–9. http://dx.doi.org/10.1155/2018/7248040.
Testo completoAbstract (sommario):
Internet of Things (IoT) network contains heterogeneous resource-constrained computing devices which has its unique reputation in IoT environments. In spite of its distinctiveness, the network performance deteriorates by the distributed contention of the nodes for the shared wireless medium in IoT. In IoT network, the Medium Access Control (MAC) layer contention impacts the level of congestion at the transport layer. Further, the increasing node contention at the MAC layer increases link layer frame drops resulting in timeouts at the transport layer segments and the performance of TCP degrades. In addition to that, the expiration of maximum retransmission attempts and the high contentions drive the MAC retransmissions and the associated overheads to reduce the link level throughput and the packet delivery ratio. In order to deal with aforementioned problems, the Adaptive Contention Window (ACW) is proposed, which aims to reduce the MAC overhead and retransmissions by determining active queue size at the contending nodes and the energy level of the nodes to improve TCP performance. Further, the MAC contention window is adjusted according to the node’s active queue size and the residual energy and TCP congestion window is dynamically adjusted based on the MAC contention window. Hence, by adjusting the MAC Adaptive Contention Window, the proposed model effectively distributes the access to medium and assures improved network throughput. Finally, the simulation study implemented through ns-2 is compared with an existing methodology such as Cross-Layer Congestion Control and dynamic window adaptation (CC-BADWA); the proposed model enhances the network throughput with the minimal collisions.
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Athanasiou, George. "Dynamic Resource Management in 802.11 Wireless Mesh Networks". Journal of Computer Networks and Communications 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/815374.
Testo completoAbstract (sommario):
The association/handoff procedures are important components in a balanced operation of 802.11-based wireless mesh networks. In this paper, we introduce the concept of cooperative association where the stations (STA) can share useful information in order to improve the performance of the association/reassociation procedures. Furthermore, in this work we introduce a load balancing mechanism that can be applied in mesh networks. This mechanism operates in a cross-layer manner taking into account uplink and downlink channel information, routing information, and congestion-based information. Our load balancing mechanism is based on a fairness index that is measured at each access point (AP) neighborhood. This index reflects the way the communication load is shared in the neighboring APs. The iterative heuristic algorithms that we propose controls the communication load of each mesh AP in a distributed manner. We evaluate the performance of our mechanisms through OPNET simulations.
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OBELOVSKA, Kvitoslava, Khrystyna PELEKH, Yury PELEKH e Yaromir SNAICHUK. "ANALYSIS OF THE CSMA/CA SCHEME FOR WIRELESS LOCAL AREA NETWORKS". Herald of Khmelnytskyi National University. Technical sciences 315, n. 6(1) (29 dicembre 2022): 148–52. http://dx.doi.org/10.31891/2307-5732-2022-315-6-148-152.
Testo completoAbstract (sommario):
The current stage of telecommunication technologies development is characterized by the rapid growth use of wireless technologies in access networks and the growth requirements for its quality. The bottleneck that significantly reduces the bandwidth of each subscriber connection is that the total bandwidth of the wireless local network is shared among its active members by the shared technology used. The access management sub-layer to the shared physical environment is responsible for this in the network architecture. The main method used at this sub-layer is the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) scheme. This work is devoted to the analysis of CSMA/CA scheme and the development of an analytical model for its further study and use for the improvement of wireless local networks. The input data is a transition state diagram of a local area wireless network station in data transmission mode. According to the CSMA/CA scheme, stations cannot change their state after starting frame transmission until a confirmation frame of successful reception arrives from the addressee or until the time to wait for it expires. Considering this, it is proposed to use a simplified transition state diagram for the analysis. The operation of the station by the simplified transition state diagram is described using a system of differential equations. As a result of the solution of this system, expressions representing the probability of the station being in each of its states as a function of the intensities of the station’s transitions from each state to another are derived. The values of these intensities depend on both the outgoing traffic of the station and the traffic in the network. The resulting expressions can be used in further work on the analysis of the CSMA/CA scheme, as they make it possible to estimate the operation of the station at different ratios of the station’s output traffic and external traffic generated by other stations of the network. This can be used to develop an enhanced algorithm station operation of wireless local area networks by adapting the parameters of the CSMA/CA scheme to specific current loads of both the station and the network.
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Seppä, Tiina. "Discussions on the Past: Shared Experience in the Collection of Finnish Folk Poetry". Journal of Finnish Studies 16, n. 2 (1 maggio 2013): 47–65. http://dx.doi.org/10.5406/28315081.16.2.05.
Testo completoAbstract (sommario):
Abstract The article examines dialogues and encounters between rune collectors and rune singers, mainly by scrutinizing one case of collaboration. How did the physical, emotional ties and commitments of the collectors themselves influence the material they collected? What does it mean if we render commitments such as family ties visible? The singer, Anni Lehtonen, interprets the material learned from older relatives and shapes it for her own needs. Then the collector, Samuli Paulaharju, interprets this information from his own perspective—a perspective that already has informed the questions posed to the interviewee. Most importantly, this perspective (pre)determines the material. This means that the material we are now able to access in the archives was already shaped by at least two interpretative processes, separate from the selection process of the Archives of the Finnish Literature Society itself. The third layer of interpretation is the lens of the interpretative, reflective researcher—and after that, the readers.
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Berkani, Lamia, e Azeddine Chikh. "A Semantic Based Approach for Knowledge Capitalization in Communities of Practice of E-Learning". International Journal of Knowledge Society Research 3, n. 4 (ottobre 2012): 1–11. http://dx.doi.org/10.4018/jksr.2012100101.
Testo completoAbstract (sommario):
Communities of Practice of E-learning (CoPEs) are considered as a virtual framework for exchanging and sharing techno-pedagogic knowledge and know-how between actors of e-learning. However, after analyzing of knowledge management modalities in some CoPEs, the authors noticed that knowledge is often represented in a way that does not facilitate its access and reuse. Accordingly, this paper focuses on knowledge capitalization in CoPEs and proposes an ontology-based framework aiming to facilitate knowledge sharing and reuse. This framework is structured into three layers: (1) the ontology layer, (2) the semantic annotation layer, and (3) the asset layer. It provides respectively, a common vocabulary within a CoPE aiming to enable a shared understanding between its members, a semantic support to annotate its knowledge assets facilitating their retrieval and reuse, and a means of storage and indexing its different assets. The paper is illustrated with a case study related to a semantic adaptive wiki, a service proposed for a CoPE made up of a teaching staff in computer science at the USTHB University in Algeria.
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Wei, Zhuangkun, Liang Wang, Schyler Chengyao Sun, Bin Li e Weisi Guo. "Graph Layer Security: Encrypting Information via Common Networked Physics". Sensors 22, n. 10 (23 maggio 2022): 3951. http://dx.doi.org/10.3390/s22103951.
Testo completoAbstract (sommario):
The proliferation of low-cost Internet of Things (IoT) devices has led to a race between wireless security and channel attacks. Traditional cryptography requires high computational power and is not suitable for low-power IoT scenarios. Whilst recently developed physical layer security (PLS) can exploit common wireless channel state information (CSI), its sensitivity to channel estimation makes them vulnerable to attacks. In this work, we exploit an alternative common physics shared between IoT transceivers: the monitored channel-irrelevant physical networked dynamics (e.g., water/oil/gas/electrical signal-flows). Leveraging this, we propose, for the first time, graph layer security (GLS), by exploiting the dependency in physical dynamics among network nodes for information encryption and decryption. A graph Fourier transform (GFT) operator is used to characterise such dependency into a graph-bandlimited subspace, which allows the generation of channel-irrelevant cipher keys by maximising the secrecy rate. We evaluate our GLS against designed active and passive attackers, using IEEE 39-Bus system. Results demonstrate that GLS is not reliant on wireless CSI, and can combat attackers that have partial networked dynamic knowledge (realistic access to full dynamic and critical nodes remains challenging). We believe this novel GLS has widespread applicability in secure health monitoring and for digital twins in adversarial radio environments.
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Gilet, Jules, Romain Conte, Claire Torchet, Lionel Benard e Ingrid Lafontaine. "Additional Layer of Regulation via Convergent Gene Orientation in Yeasts". Molecular Biology and Evolution 37, n. 2 (3 ottobre 2019): 365–78. http://dx.doi.org/10.1093/molbev/msz221.
Testo completoAbstract (sommario):
Abstract Convergent gene pairs can produce transcripts with complementary sequences. We had shown that mRNA duplexes form in vivo in Saccharomyces cerevisiae via interactions of mRNA overlapping 3′-ends and can lead to posttranscriptional regulatory events. Here we show that mRNA duplex formation is restricted to convergent genes separated by short intergenic distance, independently of their 3′-untranslated region (UTR) length. We disclose an enrichment in genes involved in biological processes related to stress among these convergent genes. They are markedly conserved in convergent orientation in budding yeasts, meaning that this mode of posttranscriptional regulation could be shared in these organisms, conferring an additional level for modulating stress response. We thus investigated the mechanistic advantages potentially conferred by 3′-UTR mRNA interactions. Analysis of genome-wide transcriptome data revealed that Pat1 and Lsm1 factors, having 3′-UTR binding preference and participating to the remodeling of messenger ribonucleoprotein particles, bind differently these messenger-interacting mRNAs forming duplexes in comparison to mRNAs that do not interact (solo mRNAs). Functionally, messenger-interacting mRNAs show limited translational repression upon stress. We thus propose that mRNA duplex formation modulates the regulation of mRNA expression by limiting their access to translational repressors. Our results thus show that posttranscriptional regulation is an additional factor that determines the order of coding genes.
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Zhao, Jia e Watanabe. "Router-integrated Cache Hierarchy Design for Highly Parallel Computing in Efficient CMP Systems". Electronics 8, n. 11 (17 novembre 2019): 1363. http://dx.doi.org/10.3390/electronics8111363.
Testo completoAbstract (sommario):
In current Chip Multi-Processor (CMP) systems, data sharing existing in cache hierarchy acts as a critical issue which costs plenty of clock cycles for maintaining data coherence. Along with the integrated core number increasing, the only shared cache serves too many processing threads to maintain sharing data efficiently. In this work, an enhanced router network is integrated within the private cache level for fast interconnecting sharing data accesses existing in different threads. All sharing data in private cache level can be classified into seven access types by experimental pattern analysis. Then, both shared accesses and thread-crossed accesses can be rapidly detected and dealt with in the proposed router network. As a result, the access latency of private cache is decreased, and a conventional coherence traffic problem is alleviated. The process in the proposed path is composed of three steps. Firstly, the target accesses can be detected by exploring in the router network. Then, the proposed replacement logic can handle those accesses for maintaining data coherence. Finally, those accesses are delivered in the proposed data deliverer. Thus, the harmful data sharing accesses are solved within the first chip layer in 3D-IC structure. The proposed system is also implemented into a cycle-precise simulation platform, and experimental results illustrate that our model can improve the Instructions Per Cycle (IPC) of on-chip execution by maximum 31.85 percent, while energy consumption can be saved by about 17.61 percent compared to the base system.
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He, Chun Lin. "The Design and Implementation of the Information Remote Monitoring and Security Management System Based on Internet". Advanced Materials Research 846-847 (novembre 2013): 1414–17. http://dx.doi.org/10.4028/www.scientific.net/amr.846-847.1414.
Testo completoAbstract (sommario):
With the development of economy, the existence and application of the inflammable, explosive, toxic and harmful gases irresistible but dangerous at the same time in the industrial production application. for the sake of minimizing potential dangers, the remote security monitoring is of great significance. With the rapid development of network technology, the Internet network technology to implement the remote monitoring can effectively avoid some potential hazards in the industrial production and other dangerous things. We can draw a conclusion from the feedback that the effect of user experience is not ideal in the actual application. So based on the analysis of the traditional structure of remote monitoring system, a new remote monitoring system is created which can avoid these shortcomings through further research. This new system consists of three parts: 1. The client: using Flex rich client technology is more convenient and suitable for communication interface and let the customer feel familiar and easy to use. 2. data management layer: it contains three parts : the Web server layer, application server and database server layer . Application server promotes system real-time performance through Web Service technology, Shared memory and streaming Socket technology, which enables clients to have direct access to the site. 3. Data acquisition layer: data will be collected in a timely manner to send to data management with GPRS technology.
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Widl, E., C. Agugiaro e P. Puerto. "FIRST STEPS TOWARDS LINKING SEMANTIC 3D CITY MODELLING AND MULTI-DOMAIN CO-SIMULATION FOR ENERGY MODELLING AT URBAN SCALE". ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-4 (19 settembre 2018): 227–34. http://dx.doi.org/10.5194/isprs-annals-iv-4-227-2018.
Testo completoAbstract (sommario):
<p><strong>Abstract.</strong> An important prerequisite for the simulation-based assessment of energy systems at urban scale is the availability of high-quality, well-formatted and semantically structured data. Unfortunately, best practices and state-of-the-art approaches for urban data modelling are hardly applied in the context of energy-related simulations, such that data management and data access often become tedious and cumbersome tasks. This paper presents the so-called Simulation Package, i.e., a data model extending the 3D City Database for CityGML, and its derived data access layer, both aiming to bridge this gap between semantic 3D city modelling and simulation in the context of urban energy systems. The feasibility of this approach is demonstrated with the help of a concrete example, where the proposed extension has been implemented and integrated into a simulation toolchain. The aim is that the availability of a common, shared data model and the proof-of-concept implementation will contribute and foster adoption and further improvement in the future.</p>
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Rendeiro, Pedro, Jamile Leite Leite, Lucas Silva, Marcos Silva, George Sales e Leonardo Ramalho. "Connectivity Evaluation of ESP32 in Outdoor Scenarios". Anais do Computer on the Beach 14 (3 maggio 2023): 333–38. http://dx.doi.org/10.14210/cotb.v14.p333-338.
Testo completoAbstract (sommario):
ABSTRACTThe purpose of this paper is to evaluate WiFi (IEEE 802.11 b/g/n)performance of ESP32 modules in outdoor scenarios using an offthe-shelf access point (AP). This was done by measuring its receivedsignal strength indicator (RSSI) and application data transfer ratesat different locations of a relatively open area, prone to possiblesources of interference, in order to simulate a real-life usage situation.The results show that this setup is suitable for medium datarate applications at distances up to 300m from the wireless accesspoint. Based on the acquired RSSI values, the achievable data rateon the PHY layer was also estimated for each point based on thehardware documentation. Throughout the text, challenges facedduring the implementation of the system are shared, as well asthe solutions found, which will be useful for those who wish toreplicate the experiment.
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El Bouchti, Abdelali, Abdelkrim Haqiq e Said El Kafhali. "Quality of Service Analysis and Queuing Performance Modeling of Orthogonal Frequency Division Multiple Access Based IEEE 802.16/WiMAX System". International Journal of Mobile Computing and Multimedia Communications 4, n. 3 (luglio 2012): 54–70. http://dx.doi.org/10.4018/jmcmc.2012070104.
Testo completoAbstract (sommario):
The authors present a problem of queuing theoretic performance modeling and analysis of Orthogonal Frequency Division Multiple Access (OFDMA) under broadband wireless networks. They consider a single-cell WiMAX environment in which the base station allocates sub channels to the subscriber stations in its coverage area. The sub channels allocated to a subscriber station are shared by multiple connections at that subscriber station. To ensure the Quality of Service (QoS) performances, a Connection Admission Control (CAC) mechanism is considered at a subscriber station. A queuing analytical framework for these admission control mechanisms is presented considering OFDMA-based transmission at the physical layer and based on the queuing model; both the connection-level and packet-level performances are studied and compared with their analogues in the case without CAC. The connection arrival is modeled by a Poisson process and the packet arrival for a connection by a Markov Modulated Poisson Process (MMPP). Several performance measures, namely connection blocking probability, average number of ongoing connections, average queue length, packet dropping probability, queue throughput and average packet delay, are then derived and quantified.
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Yin, Lujia, Yiming Zhang, Zhaoning Zhang, Yuxing Peng e Peng Zhao. "ParaX". Proceedings of the VLDB Endowment 14, n. 6 (febbraio 2021): 864–77. http://dx.doi.org/10.14778/3447689.3447692.
Testo completoAbstract (sommario):
Despite the fact that GPUs and accelerators are more efficient in deep learning (DL), commercial clouds like Facebook and Amazon now heavily use CPUs in DL computation because there are large numbers of CPUs which would otherwise sit idle during off-peak periods. Following the trend, CPU vendors have not only released high-performance many-core CPUs but also developed efficient math kernel libraries. However, current DL platforms cannot scale well to a large number of CPU cores, making many-core CPUs inefficient in DL computation. We analyze the memory access patterns of various layers and identify the root cause of the low scalability, i.e., the per-layer barriers that are implicitly imposed by current platforms which assign one single instance (i.e., one batch of input data) to a CPU. The barriers cause severe memory bandwidth contention and CPU starvation in the access-intensive layers (like activation and BN). This paper presents a novel approach called ParaX, which boosts the performance of DL on many-core CPUs by effectively alleviating bandwidth contention and CPU starvation. Our key idea is to assign one instance to each CPU core instead of to the entire CPU, so as to remove the per-layer barriers on the executions of the many cores. ParaX designs an ultralight scheduling policy which sufficiently overlaps the access-intensive layers with the compute-intensive ones to avoid contention, and proposes a NUMA-aware gradient server mechanism for training which leverages shared memory to substantially reduce the overhead of per-iteration parameter synchronization. We have implemented ParaX on MXNet. Extensive evaluation on a two-NUMA Intel 8280 CPU shows that ParaX significantly improves the training/inference throughput for all tested models (for image recognition and natural language processing) by 1.73X ~ 2.93X.
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Bolton, Rosie, Simone Campana, Andrea Ceccanti, Xavier Espinal, Aristeidis Fkiaras, Patrick Fuhrmann e Yan Grange. "ESCAPE prototypes a data infrastructure for open science". EPJ Web of Conferences 245 (2020): 04019. http://dx.doi.org/10.1051/epjconf/202024504019.
Testo completoAbstract (sommario):
The European-funded ESCAPE project will prototype a shared solution to computing challenges in the context of the European Open Science Cloud. It targets Astronomy and Particle Physics facilities and research infrastructures and focuses on developing solutions for handling Exabyte scale datasets. The DIOS work package aims at delivering a Data Infrastructure for Open Science. Such an infrastructure would be a non HEP specific implementation of the data lake concept elaborated in the HSF Community White Paper and endorsed in the WLCG Strategy Document for HL-LHC. The science projects in ESCAPE are in different phases of evolution. While HL-LHC can leverage 15 years of experience of distributed computing in WLCG, other sciences are building now their computing models. This contribution describes the architecture of a shared ecosystem of services fulfilling the needs in terms of data organisation, management and access for the ESCAPE community. The backbone of such a data lake will consist of several storage services operated by the partner institutes and connected through reliable networks. Data management and organisation will be orchestrated through Rucio. A layer of caching and latency hiding services, supporting various access protocols will serve the data to heterogeneous facilities, from conventional Grid sites to HPC centres and Cloud providers. The authentication and authorisation system will be based on tokens. For the success of the project, DIOS will integrate open source solutions which demonstrated reliability and scalability as at the multi petabyte scale. Such services will be configured, deployed and complemented to cover the use cases of the ESCAPE sciences which will be further developed during the project.
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ElAshry, Abdelrahman F., Mohamed M. Ramadan, Ziad A. ElAlaily, Mahmoud M. Zaied, Catherine M. Elias, Omar M. Shehata e Elsayed I. Morgan. "Development of a hybrid multi-layer control architecture for a cooperative team of N − homogeneous robots". Transactions of the Institute of Measurement and Control 42, n. 3 (27 settembre 2019): 404–21. http://dx.doi.org/10.1177/0142331219872862.
Testo completoAbstract (sommario):
This paper proposes a hybrid centralized control architecture for formation control of N-homogeneous mobile robots. The addressed problem is maintaining an equilateral triangular formation using three mobile robots while moving towards a desired target avoiding any collision. The proposed architecture is divided into four main subsystems; a main path-planner, a nonlinear Lyapunov-based controller, a Secure Shell (SSH) communication module and an image processing algorithm. The main path-planner subsystem itself is subdivided into three algorithms; brain-like algorithm, sub-path-planner and an information center algorithm. The brain-like algorithm is responsible for all the decision making. On the other hand, the sub-path-planner works on translating the decisions of the brain into more precise decisions to the individual robots. Meanwhile, the information center acts as the memory for the brain to access saved information previously shared between the robots. It is shown that the control algorithm allows any initial allocation of the three robots to converge to a triangle formation in an optimal manner while avoiding collisions. Finally, the potential use of this formation as a platform acting as an autonomous mobile helipad is introduced as a practical application for the proposed architecture.
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Qi, Min, e Junshu Wang. "Using the Internet of Things E-Government Platform to Optimize the Administrative Management Mode". Wireless Communications and Mobile Computing 2021 (26 luglio 2021): 1–11. http://dx.doi.org/10.1155/2021/2224957.
Testo completoAbstract (sommario):
This paper builds an intelligent E-Government platform based on the Internet of Things. It adopts a three-layer architecture model, including the government collection layer, the government network layer, and the government application layer. By making full use of data technology and information technology, government services can be realized in real-time perception, efficient operation, scientific decision-making, active service, and intelligent supervision and can be open and collaborative, so as to provide the public with better quality and more efficient and more responsive government services. In addition, this paper has realized optimization in the aspects of government service mode, Internet of Things application mode, and database structure. Through the use of big data technology, the government service information will be digitized and integrated, and through the data sharing and exchange platform, the government information resources will be intercommunicated and shared across departments, levels, and regions. The application mode has been upgraded. Compared with the traditional E-Government, the government has made a qualitative leap in the degree of automation of control, the intelligence of service and decision, the remote support ability, and the space-time scope that government can control. The distributed management mode of the SQL Server is adopted to realize the exchange of requested data and process the data content, which can greatly improve the working efficiency of the system. Finally, through testing, the government affairs management system has good stability; there is no congestion and delay when multiple users access the system, so the response speed and efficiency of the system basically meet the requirements.
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Formosa, Saviour, Janice Formosa Pace e Elaine Sciberras. "Spatial Information Preparedness for Environmental Enforcement in the Maltese Islands". International Journal of Agricultural and Environmental Information Systems 4, n. 3 (luglio 2013): 1–17. http://dx.doi.org/10.4018/ijaeis.2013070101.
Testo completoAbstract (sommario):
Spatial analysis of the environment takes place within various competing but parallel domains; physical, social, and natural environments partake to datasets that have the same baseline requirements as are a reliable topographic layer, updated aerial/remote imagery and dissemination tools. The process has proven to be arduous, expensive and barrier-strewn due to data costs, access issues and lack of interactive sites. The Maltese Islands have implemented a system that integrates the transposition of legislative measures as well as ensuring free dissemination through the launching of an initiative based on the Shared Environmental Information System (SEIS). The latter activity sought to take the next step into the dissemination of spatial and environmental data to the academic, scientific and public communities. The Malta initiative was aimed to take national environmental monitoring capacity and the relative enforcement processes to a fully interactive online system, where users can analyse the potential infringements.
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STINE, JOHN A., GUSTAVO DE VECIANA, KEVIN H. GRACE e ROBERT C. DURST. "ORCHESTRATING SPATIAL REUSE IN WIRELESS AD HOC NETWORKS USING SYNCHRONOUS COLLISION RESOLUTION (SCR)". Journal of Interconnection Networks 03, n. 03n04 (settembre 2002): 167–95. http://dx.doi.org/10.1142/s0219265902000616.
Testo completoAbstract (sommario):
We propose a novel medium access control protocol for ad hoc wireless networks data to send can contend simultaneously for the channel. Nodes contend for access using a synchronous signaling mechanism that achieves two objectives: it arbitrates contentions locally and it selects a subset of nodes across the network that attempt to transmit simultaneously. The subset of nodes that survive the signaling mechanism can be viewed as an orchestrated set of transmissions that are spatially reusing the channel shared by the nodes. Thus the 'quality' of the subset of nodes selected by the signaling mechanism is a key factor in determining the spatial capacity of the system. In this paper, we propose a general model for such synchronous signaling mechanisms and recommend a preferred design. We then focus via both analysis and simulation on the spatial and capacity characteristics of these access control mechanisms. Our work is unique in that it specifically focuses on the spatial capacity aspects of a MAC protocol, as would be critical for ad hoc networking, and shows SCR is a promising solution. Specifically, it does not suffer from congestion collapse as the density of contending nodes grows, it does not suffer from hidden or exposed node effects, it achieves high capacities with a spatial usage exceeding 1 (i.e. more than one packet exchange in the area covered by a transmission), and it facilitates the integration of new physical layer capacity increasing technologies.
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Chitra, P., e M. Chandrasekaran. "Novel Energy-Efficient Congestion Control Protocol in Wireless Networks Using Evolutionary Game Paradigm". Journal of Computational and Theoretical Nanoscience 14, n. 1 (1 gennaio 2017): 460–67. http://dx.doi.org/10.1166/jctn.2017.6346.
Testo completoAbstract (sommario):
In recent years, Wireless Network technology was designed for short distance communications like ZigBee, Bluetooth and Infrared Transmission. Congestion degrades the performance of the wireless network and also reduces the battery life of a mobile node. Congestion control is very much essential in the transport layer to prevent performance degradation in a wireless network. Congestion control mechanism restricts the packet transmission rate with respect to the shared network resources. In this work, we designed a novel Energy-Efficient Congestion Control Protocol using Evolutionary Game model (EECCP-EG) for reducing congestion in wireless network. The main objective of the EECCP-EG is stability analysis with different strategy spaces in a network in which losing strategies are eliminated and winning strategies are remain for stability. The proposed EECCP-EG uses symmetric hawk-dove game to access the shared network recourse for preventing congestion in wireless network. In this, Evolutionary Stable Strategies (ESS) is used to change their strategies dynamically based on fitness value of winning resources and achieves equilibrium. The increase or decrease in the rate of data transmission defines the aggressiveness of the symmetric hawk-dove game. The transmission control protocols (TCP) with an additive-increase multiplicative-decrease mechanism control the aggressiveness of the protocol. Simulation results show that the proposed EECCP-EG scheme could significantly minimize the network traffic and there by reduce the congestion in the networks.
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Gan, Yulu, Yan Bai, Yihang Lou, Xianzheng Ma, Renrui Zhang, Nian Shi e Lin Luo. "Decorate the Newcomers: Visual Domain Prompt for Continual Test Time Adaptation". Proceedings of the AAAI Conference on Artificial Intelligence 37, n. 6 (26 giugno 2023): 7595–603. http://dx.doi.org/10.1609/aaai.v37i6.25922.
Testo completoAbstract (sommario):
Continual Test-Time Adaptation (CTTA) aims to adapt the source model to continually changing unlabeled target domains without access to the source data. Existing methods mainly focus on model-based adaptation in a self-training manner, such as predicting pseudo labels for new domain datasets. Since pseudo labels are noisy and unreliable, these methods suffer from catastrophic forgetting and error accumulation when dealing with dynamic data distributions. Motivated by the prompt learning in NLP, in this paper, we propose to learn an image-layer visual domain prompt for target domains while having the source model parameters frozen. During testing, the changing target datasets can be adapted to the source model by reformulating the input data with the learned visual prompts. Specifically, we devise two types of prompts, i.e., domains-specific prompts and domains-agnostic prompts, to extract current domain knowledge and maintain the domain-shared knowledge in the continual adaptation. Furthermore, we design a homeostasis-based adaptation strategy to suppress domain-sensitive parameters in domain-invariant prompts to learn domain-shared knowledge more effectively. This transition from the model-dependent paradigm to the model-free one enables us to bypass the catastrophic forgetting and error accumulation problems. Experiments show that our proposed method achieves significant performance gains over state-of-the-art methods on four widely-used benchmarks, including CIFAR-10C, CIFAR-100C, ImageNet-C, and VLCS datasets.
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Khisa, Shreya, e Sangman Moh. "Medium Access Control Protocols for the Internet of Things Based on Unmanned Aerial Vehicles: A Comparative Survey". Sensors 20, n. 19 (29 settembre 2020): 5586. http://dx.doi.org/10.3390/s20195586.
Testo completoAbstract (sommario):
The Internet of Things (IoT), which consists of a large number of small low-cost devices, has become a leading solution for smart cities, smart agriculture, smart buildings, smart grids, e-healthcare, etc. Integrating unmanned aerial vehicles (UAVs) with IoT can result in an airborne UAV-based IoT (UIoT) system and facilitate various value-added services from sky to ground. In addition to wireless sensors, various kinds of IoT devices are connected in UIoT, making the network more heterogeneous. In a UIoT system, for achieving high throughput in an energy-efficient manner, it is crucial to design an efficient medium access control (MAC) protocol because the MAC layer is responsible for coordinating access among the IoT devices in the shared wireless medium. Thus, various MAC protocols with different objectives have been reported for UIoT. However, to the best of the authors’ knowledge, no survey had been performed so far that dedicatedly covers MAC protocols for UIoT. Hence, in this study, state-of-the-art MAC protocols for UIoT are investigated. First, the communication architecture and important design considerations of MAC protocols for UIoT are examined. Subsequently, different MAC protocols for UIoT are classified, reviewed, and discussed with regard to the main ideas, innovative features, advantages, limitations, application domains, and potential future improvements. The reviewed MAC protocols are qualitatively compared with regard to various operational characteristics and system parameters. Additionally, important open research issues and challenges with recommended solutions are summarized and discussed.
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Camacho, Agustín, Carlos A. Navas, Adriana Tiemi Yamanouchi e Miguel Trefaut Rodrigues. "Consequences of Evolving Limbless, Burrowing Forms for the Behavior and Population Density of Tropical Lizards". Diversity 14, n. 6 (14 giugno 2022): 482. http://dx.doi.org/10.3390/d14060482.
Testo completoAbstract (sommario):
We quantified functional traits (escape strategy, sprint speed and predatory performance) and population density across 10 lizard species representing morphotype stages in the acquisition of burrowing snake-like morphotypes (BSLM), from Brazil. We used phylogenetic mixed models to test if: (a) morphotype and substrate affects flight strategy and speed, (b) BSLM species more effectively access different potential prey types than lacertoid species, when in syntopy, and (c) morphotype is correlated with population abundance and habitat use in a way expected from the output of the previous experiments. BSLM rigidly relied on burrowing as flight strategy, while syntopic lacertoid species changed their strategy according to the substrate. In addition, sand had opposing effects on sprint speed depending on morphotype, making lacertoids run more slowly and BSLM faster. Even though BSLM were overall slower than lacertoids, they were equally effective hunters of challengingly fast prey, and better hunters of underground prey. In their shared habitats, prey is most abundant in the superficial layer of leaf litter, although a large fraction is found beneath this layer, under bushes. Experimental results support the observed higher importance of sand for BSLM’s density and the higher importance of vegetation for lacertoids’ density. Finally, although BSLM species reached the highest population densities among the studied species, a systematic effect of morphological evolution on the abundance of limbless lizards remains elusive.
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Farooq, Muhammad Omer, e Thomas Kunz. "Contiki-Based IEEE 802.15.4 Channel Capacity Estimation and Suitability of Its CSMA-CA MAC Layer Protocol for Real-Time Multimedia Applications". Mobile Information Systems 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/398637.
Testo completoAbstract (sommario):
Real-time multimedia applications require quality of service (QoS) provisioning in terms of bounds on delay and packet loss along with soft bandwidth guarantees. The shared nature of the wireless communication medium results in interference. Interference combined with the overheads, associated with a medium access control (MAC) protocol, and the implementation of a networking protocol stack limit the available bandwidth in IEEE 802.15.4-based networks and can result in congestion, even if the transmission rates of nodes are well below the maximum bandwidth supported by an underlying communication technology. Congestion degrades the performance of admitted real-time multimedia flow(s). Therefore, in this paper, we experimentally derive the IEEE 802.15.4 channel capacity using an unslotted CSMA-CA MAC protocol. We experimentally derive channel capacity for two cases, that is, when the CSMA-CA protocol is working without ACKs and when it is working with ACKs. Moreover, for both cases, we plot the relationship of offered data load with delay and packet loss rate. Simulation results demonstrate that the parameters that affect the choice of a CSMA-CA MAC layer protocol are end-to-end delay and packet loss requirements of a real-time multimedia flow, data load within the interference range of transmitters along the forwarding path, and length of the forwarding path.
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Wiener, Antje. "Contested Norms in Inter-National Encounters: The ‘Turbot War’ as a Prelude to Fairer Fisheries Governance". Politics and Governance 4, n. 3 (11 agosto 2016): 20–36. http://dx.doi.org/10.17645/pag.v4i3.564.
Testo completoAbstract (sommario):
This article is about contested norms in inter-national encounters in global fisheries governance. It illustrates how norms work by reconstructing the trajectory of the 1995 ‘Turbot War’ as a series of inter-national encounters among diverse sets of Canadian and European stakeholders. By unpacking the contestations and identifying the norms at stake, it is suggested that what began as action at cross-purposes (i.e. each party referring to a different fundamental norm), ultimately holds the potential for fairer fisheries governance. This finding is shown by linking source and settlement of the dispute and identifying the shared concern for the balance between the right to fish and the responsibility for sustainable fisheries. The article develops a framework to elaborate on procedural details including especially the right for stakeholder access to regular contestation. It is organised in four sections: section 1 summarises the argument, section 2 presents the framework of critical norms research, section 3 reconstructs contestations of fisheries norms over the duration of the dispute, and section 4 elaborates on the dispute as a prelude to fairer fisheries governance. The latter is based on a novel conceptual focus on stakeholder access to contestation at the meso-layer of fisheries governance where organising principles are negotiated close to policy and political processes, respectively. The conclusion suggests for future research to pay more attention to the link between the ‘is’ and the ‘ought’ of norms in critical norms research in International Relations theories (IR).
31
Ball, Joyelle. "“The Ghosts Are Watching”: The Globe's Battlefield Performances ofHenry VI". Theatre Survey 59, n. 1 (gennaio 2018): 45–62. http://dx.doi.org/10.1017/s0040557417000485.
Testo completoAbstract (sommario):
In the summer of 2013, Shakespeare's Globe, the company based at the Globe reconstruction in London, mounted productions of the three parts of Shakespeare'sHenry VIat Wars of the Roses battlefield sites. The battlefield as performance space, with its rolling hills and buried corpses, mediated the temporal overlap of past and present, as contemporary bodies engaged with the construction of a historical narrative in the fictional play and the actual historical moments of the Wars of the Roses. The associations entrenched in the soil of these sites, the physical remains and histories of the past, encode a connective experience for the contemporary participants interacting with it. The battlefield site, then, is not just a site of historical significance—it is also a site of historical reenactment, where present bodies meet absent ones in the Globe's attempt to converge separated temporalities. The Globe framed the battlefield performances as a way of enlivening history by grounding well-worn Shakespearean texts in the places they represent. But the Globe, in collaboration with The Space, an online arts collective, also filmed the ten-hour marathon event at the Barnet battlefield, live-streamed, and then saved the performance to a digital archive. So the Globe displaced the site of their site-specific experience. Virtual spectatorship, a result of the Globe's efforts to increase access to their battlefield performances by making them available online, adds another layer of absence to the battlefield. The virtual spectator as absent spectator challenges the privileging of a physical viewing experience that the Globe's “open-air” project promotes. The displacement of site disrupts the relationships grounded in the material performance space and its geographical connections, and expands the understanding ofsite-specificby demonstrating how a specific relationship to place might be produced and maintained without physical access to a geographical location. Together with their placement at the historical sites and transmission into virtual spaces, the battlefieldHenry VIs generate a multiplicity of shared viewing experiences. These shared experiences mediate the continuation of a (re)constructed historical and collective memory and highlight the role of spectatorship, both physical and virtual, in the formation of communal and national identity.
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Valentini, Roberto, Piergiuseppe Di Marco e Fortunato Santucci. "Exploiting Capture Diversity for Performance Enhancement of ALOHA-Based Multi-Static Backscattering Systems in the 6G Perspective". Sensors 21, n. 15 (27 luglio 2021): 5070. http://dx.doi.org/10.3390/s21155070.
Testo completoAbstract (sommario):
In this paper, we consider the emerging context of ALOHA-based multi-static backscattering communication systems. By assuming an architecture consisting of a set of passive backscattering nodes, an illuminator, and a set of spatially dislocated receivers, we firstly propose a cross-layer framework for performance analysis. The model jointly accounts for the shared wireless channel, including fading and capture effect, and channel contention strategy, which is regulated by a Framed Slotted ALOHA protocol. Furthermore, based on the inherent macroscopic diversity offered by the multi-static settings, we introduce the concept of capture diversity, which is shown to enable multiple packet detection in slots with multiple transmissions. In order to characterize the multiple access interference and approximate the capture probabilities, we enforce a log-normal approximation of the inverse Signal-to-Interference Ratio that relies on moment matching. Numerical results show the impact of deployment scenarios and the relative positions of illuminator, backscattering nodes, and receivers on the system normalized throughput. We show how the number of detection points impacts the system performance under various channel conditions. Moreover, the accuracy of the proposed approximation rationale is validated via Monte Carlo simulations. Finally, we analyze the optimal frame length in the presence of capture diversity.
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Hadi, Teeb Hussein. "Types of Attacks in Wireless Communication Networks". Webology 19, n. 1 (20 gennaio 2022): 718–28. http://dx.doi.org/10.14704/web/v19i1/web19051.
Testo completoAbstract (sommario):
One of the most important types that used to transfer data between nodes without using wires is a “wireless communication network”, where the transmission of data is censored remotely by using electromagnetic waves such as radio waves that usually implemented in the physical layer of the network. Continuous improvements in wireless network technology have reduced the security and speed differences between types of networks (wired and wireless), but in turn, increased security threats to wirelessly transmitted data. Wireless networks are weak in terms of "privacy protection" because anyone who is within the coverage area of a wireless network can attempt to break into that network. Hacking incidents have been reported frequently in places with shared free networks, and it has been observed that the places of open distributed networks of the Internet are most at risk of complete penetration of your phone or PC data. To solve this problem, several programs have been developed that provide protection for wireless networks that differ in terms of security. Some of them did not provide sufficient protection for wireless networks, such as Wired Equivalent Privacy (WEP), and others made progress in preventing intrusions compared to their predecessors, such as Wi-Fi Protected Access (WPA).
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Maryam, Siti, e Jerry Indrawan. "RELATIONS BETWEEN MEDIA AND CONFLICT:". Book Chapters of The 1st Jakarta International Conference on Social Sciences and Humanities (JICoSSH) 1 (27 gennaio 2019): 114–32. http://dx.doi.org/10.33822/jicossh.v1i1.8.
Testo completoAbstract (sommario):
Civil society is considered to be the arena of voluntary and collective action among shared interests, purposes and values that strengthens the social foundations of democracy in a state. As a part of the civil society, media enable every layer of the society to access free and open information. In other words, media with its journalistic products has become a free market to every element of the society to promote their ideas. Media will fight for influence, claim for the truth, and perform their own version of social reality. Not only as a channel, media can also place itself as a doer in defining social reality and pick any important and relevant issues. The content of mass media cannot be separated from news about conflict, especially those related to human rights. The term “Bad news is good news” seems to be the perspective use by reporters in their writings. News on conflict always becomes major headlines in many world newspapers, including Indonesia. Hard to deny that media, unaware or even aware, has make news on conflicts as a commodity, thus creating widespread public opinion. In a fragile democracy directed public opinion could jeopardize the structure of democratic civil society and human rights basis. That is why conflicts could threaten civil society life, especially here in Indonesia. Media role in reporting conflict has become a serious challenge for Indonesian democratic civil society life.
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CHEN, ZHONGQIANG, ALEX DELIS e PETER WEI. "IDENTIFICATION AND MANAGEMENT OF SESSIONS GENERATED BY INSTANT MESSAGING AND PEER-TO-PEER SYSTEMS". International Journal of Cooperative Information Systems 17, n. 01 (marzo 2008): 1–51. http://dx.doi.org/10.1142/s0218843008001750.
Testo completoAbstract (sommario):
Sessions generated by Instant Messaging and Peer-to-Peer systems (IM/P2Ps) not only consume considerable bandwidth and computing resources but also dramatically change the characteristics of data flows affecting both the operation and performance of networks. Most IM/P2Ps have known security loopholes and vulnerabilities making them an ideal platform for the dissemination of viruses, worms, and other malware. The lack of access control and weak authentication on shared resources further exacerbates the situation. Should IM/P2Ps be deployed in production environments, performance of conventional applications may significantly deteriorate and enterprise data may be contaminated. It is therefore imperative to identify, monitor and finally manage IM/P2P traffic. Unfortunately, this task cannot be easily attained as IM/P2Ps resort to advanced techniques to hide their traces including multiple channels to deliver services, port hopping, message encapsulation and encryption. In this paper, we propose an extensible framework that not only helps to identify and classify IM/P2P-generated sessions in real time but also assists in the manipulation of such traffic. Consisting of four modules namely, session manager, traffic assembler, IM/P2P dissector, and traffic arbitrator, our proposed framework uses multiple techniques to improve its traffic classification accuracy and performance. Through fine-tuned splay and interval trees that help organize IM/P2P sessions and packets in data streams, we accomplish stateful inspection, traffic re-assembly, data stream correlation, and application layer analysis that combined will boost the framework's identification precision. More importantly, we introduce IM/P2Ps "plug-and-play" protocol analyzers that inspect data streams according to their syntax and semantics; these analyzers render our framework easily extensible. Identified IM/P2P sessions can be shaped, blocked, or disconnected, and corresponding traffic can be stored for forensic analysis and threat evaluation. Experiments with our prototype show high IM/P2Ps detection accuracy rates under diverse settings and excellent overall performance in both controlled and real-world environments.
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Safdari, Fash, e Anatoliy Gorbenko. "Theoretical and experimental study of performance anomaly in multi-rate IEEE802.11ac wireless networks". Radioelectronic and Computer Systems, n. 4 (29 novembre 2022): 85–97. http://dx.doi.org/10.32620/reks.2022.4.06.
Testo completoAbstract (sommario):
IEEE 802.11 wireless local area networks (WLANs) are shared networks, which use contention-based distributed coordination function (DCF) to share access to wireless medium among numerous wireless stations. The performance of the distributed coordination function mechanism mostly depends on the network load, number of wireless nodes and their data rates. The throughput unfairness, also known as performance anomaly is inherent in the very nature of mixed data rate Wi-Fi networks using the distributed coordination function. This unfairness exhibits itself through the fact that slow clients consume more airtime to transfer a given amount of data, leaving less airtime for fast clients. In this paper, we comprehensively examine the performance anomaly in multi-rate wireless networks using three approaches: experimental measurement, analytical modelling and simulation in Network Simulator v.3 (NS3). The results of our practical experiments benchmarking the throughput of a multi-rate 802.11ac wireless network clearly shows that even the recent wireless standards still suffer from airtime consumption unfairness. It was shown that even a single low-data rate station can decrease the throughput of high-data rate stations by 3–6 times. The simulation and analytical modelling confirm this finding with considerably high accuracy. Most of the theoretical models evaluating performance anomaly in Wi-Fi networks suggest that all stations get the same throughput independently of the used data rate. However, experimental and simulation results have demonstrated that despite a significant performance degradation high-speed stations still outperform stations with lower data rates once the difference between data rates becomes more significant. This is due to the better efficiency of the TCP protocol working over a fast wireless connection. It is also noteworthy that the throughput achieved by a station when it monopolistically uses the wireless media is considerably less than 50 % of its data rate due to significant overheads even in most recent Wi-Fi technologies. Mitigating performance anomaly in mixed-data rate WLANs requires a holistic approach that combines frame aggregation/fragmentation and adaption of data rates, contention window and other link-layer parameters.
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Dammak, Bouthaina, Mariem Turki, Saoussen Cheikhrouhou, Mouna Baklouti, Rawya Mars e Afef Dhahbi. "LoRaChainCare: An IoT Architecture Integrating Blockchain and LoRa Network for Personal Health Care Data Monitoring". Sensors 22, n. 4 (15 febbraio 2022): 1497. http://dx.doi.org/10.3390/s22041497.
Testo completoAbstract (sommario):
Over the past several years, the adoption of HealthCare Monitoring Systems (HCS) in health centers and organizations like hospitals or eldery homes growth significantly. The adoption of such systems is revolutionized by a propelling advancements in IoT and Blockchain technologies. Owing to technological advancement in IoT sensors market, innovations in HCS to monitor patients health status have motivated many countries to strength their efforts to support their citizens with such care delivery systems under the directives of a physician who has access to patient’s data. Nevertheless, secure data sharing is a principal patient’s concern to be comfort to use such systems. Current HCS are not able to provide reassuring security policies. For that, one of our focus in this work, is to provide security countermeasures, likewise cost-efficient solution for HCS by integrating storage model based on Blockchain and Interplanetary File Systems (IPFS). Blockchain technology is an emerging solution in pharmaceutical industry and starts to take place for HCS and allows HealthCare providers to track connected devices and control access to shared data, hence protecting patients’ privacy. Furthermore, the addition of Edge and Fog computing has improved HCS to react in real-time and enhance their reliability. A variety of communication protocols can connect sensor devices to edge/Fog layer and the best choice will depend upon connectivity requirements: range, bandwidth, power, interoperability, security, and reliability. Instead, systems efficiency would decline and hurt if communication protocol is inconsistent. LoRa (Long Range) communications technology is emerging as the leader among Low-Power Wide-Area Networks (LPWANs) entering the IoT domain benefiting from many features such as long-range distances and low power consumption. This work proposes LoRaChainCare, an architecture model for HCS which combines the technologies Blockchain, Fog/Edge computing, and the LoRa communication protocol. A real implementation of LoRaChainCare system is presented and evaluated in terms of cost, run time and power consumption.
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Cook, Michael J., e Isabelle Chambrier. "Unmasking the chemistry and properties of non-peripherally octasubstituted phthalocyanines". Journal of Porphyrins and Phthalocyanines 15, n. 03 (marzo 2011): 149–73. http://dx.doi.org/10.1142/s1088424611003100.
Testo completoAbstract (sommario):
The paper reviews the development of the chemistry, properties and applications of 1,4,8,11,15,18,22,25- (or non-peripheral) octasubstituted phthalocyanines that has been undertaken at the University of East Anglia over the last quarter of a century. The research has proved valuable for initiating and developing a number of areas of phthalocyanine science, not least because the compounds exhibit a number of properties seldom shared by Pc derivatives with other substitution patterns. In particular the compounds are obtained isomerically pure and the substituents' location at the non-peripheral sites as opposed to the peripheral positions ensures superior solubility and lower aggregation in most hydrophobic solvents. A further significant difference between isomeric non-peripheral (np)- and peripheral (p)-octasubstituted compounds is the effect of substituents on the energy of the Q-band, those at the former positions leading to more significant bathochromic shifts of this absorption band into the near infra-red. Examples of np-octasubstituted derivatives exhibit columnar mesophase behavior, a property shared by their p-octasubstituted counterparts. The favorable solubility of the np-octasubstituted compounds, including examples in which one of the four benzenoid rings bears different substituents from those on the other three (so called AAAB structures), in organic solvents facilitates their deposition as thin film formulations. A high degree of molecular organisation within Langmuir-Blodgett (LB) films of amphiphilic AAAB compounds has been investigated using various methods. Spin-coated films of certain AAAA and AAAB series of compounds have been shown to contain layer structuring and purpose designed AAAB compounds have been used in formation of self-assembled monolayers (SAMs). The use of LB and spin-coated films within electrical devices is described. Various applications of SAMs deposited on gold surfaces have been explored including gas sensing. Recent attention has focused on their use, when deposited onto gold nanoparticles, for applications in PDT, an approach complementing more conventional PDT studies. The principal challenge for obtaining the np-octasubstituted compounds is in preparing the precursor phthalonitriles. Though 3,6-dialkoxyphthalonitriles are readily prepared, early access to the 3,6-dialkylphthalonitriles was somewhat laborious. However, more convenient syntheses of the latter are now available through metal catalyzed cross-coupling reactions. Interesting contrasts in the reactivity of 3,6-dialkylphthalonitriles and 4,5-dialkylphthalonitriles have been uncovered. Thus reactions of the former with excess lithium in alcoholic solvents or with excess MeMgBr provide particularly ready access to examples of macrocycles that are hybrids of the Pc and tetrabenzoporphyrin structures. This level of reactivity is very different among the 4,5-dialkylphthalonitriles. Unexpectedly limited reactivity of np-octahexylsubstituted Si(OH)2Pc in condensation reactions has been exploited to provide a basis for the stepwise construction of m-oxo linked hetero-chromophore arrays. Finally, the unexpected construction of the novel EPR active Cd2Pc3 complexes from both np- and p-octaalkyl substituted CdPcs provided examples where both series behaved similarly – in contrast to behavior exhibited by alternatively substituted CdPcs investigated to date.
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Hussain, Md, e M. M. Beg. "Fog Computing for Internet of Things (IoT)-Aided Smart Grid Architectures". Big Data and Cognitive Computing 3, n. 1 (19 gennaio 2019): 8. http://dx.doi.org/10.3390/bdcc3010008.
Testo completoAbstract (sommario):
The fast-paced development of power systems necessitates the smart grid (SG) to facilitate real-time control and monitoring with bidirectional communication and electricity flows. In order to meet the computational requirements for SG applications, cloud computing (CC) provides flexible resources and services shared in network, parallel processing, and omnipresent access. Even though CC model is considered to be efficient for SG, it fails to guarantee the Quality-of-Experience (QoE) requirements for the SG services, viz. latency, bandwidth, energy consumption, and network cost. Fog Computing (FC) extends CC by deploying localized computing and processing facilities into the edge of the network, offering location-awareness, low latency, and latency-sensitive analytics for mission critical requirements of SG applications. By deploying localized computing facilities at the premise of users, it pre-stores the cloud data and distributes to SG users with fast-rate local connections. In this paper, we first examine the current state of cloud based SG architectures and highlight the motivation(s) for adopting FC as a technology enabler for real-time SG analytics. We also present a three layer FC-based SG architecture, characterizing its features towards integrating massive number of Internet of Things (IoT) devices into future SG. We then propose a cost optimization model for FC that jointly investigates data consumer association, workload distribution, virtual machine placement and Quality-of-Service (QoS) constraints. The formulated model is a Mixed-Integer Nonlinear Programming (MINLP) problem which is solved using Modified Differential Evolution (MDE) algorithm. We evaluate the proposed framework on real world parameters and show that for a network with approximately 50% time critical applications, the overall service latency for FC is nearly half to that of cloud paradigm. We also observed that the FC lowers the aggregated power consumption of the generic CC model by more than 44%.
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Depmeier, Wulf, Nikita Chukanov e Igor Pekov. "New Minerals from the Classic Eifel Region". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1090. http://dx.doi.org/10.1107/s2053273314089098.
Testo completoAbstract (sommario):
In the recent four years, the authors have jointly organized and conducted several excursions into the classical volcanic field in the Eifel area, Germany. The original goal was to compare its geochemistry and mineralogy with those of the hyperalkaline intrusions of Khibiny and Lovozero on Kola peninsula, Russia. Since none of us had previous experience with the Eifel area, local amateur mineral collectors were contacted and asked for support. These collectors often have been active in their region for decades and, hence, know the various deposits and minerals by heart. Our request was met with great enthusiasm and invaluable support was given to us not only with respect to the organization of the excursions, but the collectors also shared their experience with getting access to the quarries and often offered samples from their own, very well organized and documented, collections. It soon turned out, that – a bit to our surprise - even in such a classical area as the Eifel with its long tradition of geological and mineralogical research new minerals can be found. As a result, 16 new minerals from the Eifel could be described, accepted by IMA, and the results published. Others are still under study. Some of these minerals were found in the field, others were donated by local mineral collectors. In acknowledgement of their invaluable contribution, several minerals now bear names of those or other local collectors. Several of the new minerals belong to well-known mineral groups, but a few represent quite new structures. For example, in the mineral hielscherite, the pyramidal sulfite anion substitutes for planar carbonate in thaumasite, and günterblassite is the first phyllosilicate with a triple tetrahedral layer, thus indicating somehow a structural transition into a tectosilicate.
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Darwanto, Agus, e Mohammad Alfin Khoiri. "IMPLEMENTASI SAMBA PRIMARY DOMAIN CONTROLLER, MANAJEMEN BANDWIDTH, DAN PEMBATASAN AKSES WEBSITE UNTUK MENINGKATKAN EFEKTIFITAS KEGIATAN PEMBELAJARAN DI LABORATORIUM TEKNIK KOMPUTER & JARINGAN SMKN 1 DLANGGU". KONVERGENSI 17, n. 2 (10 febbraio 2022): 89–101. http://dx.doi.org/10.30996/konv.v17i2.5478.
Testo completoAbstract (sommario):
ABSTRACTThere are no shared storage that is centralized in the server requires students to store their files into extended storage such as a flash drive. Primary Domain Controller as centralized storage for each client with a login system for each user provides an alternative centralized personal storage with the resources provided by the server. With a centralized server, the user makes it easy to store files without fear of being swapped by other users. While the absence of website limitations that cannot be accessed at certain hours such as productive learning hours can reduce student learning focus because the bandwidth management manages the distribution of internet connection speeds evenly on each client. By using layer 7 protocol method and Address List as a means of limiting access to certain websites as well as Ubuntu Linux as a centralized server facility with the addition of hotspot management as a means of wireless internet connection for students with a personal authentication system without using a conventional password results in a local server domain controller which cannot be accessed by parties outside the network itself. The distribution of internet bandwidth for students is a maximum of 1024kbps and has an average speed of 700-1024kbps. While blocking certain websites such as YouTube, Facebook, Instagram, etc., will be limited by the layer 7 protocol method which results in blocked sites. The logging of IP addresses from online games is done automatically and dynamically by the Address List method with the result of all games that are disabled cannot be accessed from either a wired or wireless connection.
Keywords: samba, domain controller, mikrotik, bandwidth management
ABSTRAKTidak adanya sharing storage yang terpusat pada server mengharuskan siswa untuk menyimpan semua file,seperti tugas ataupun referensi pembelajaran yang telah dikerjakan ke dalam extend storage seperti flashdisk. Primary Domain Controller sebagai penyimpanan terpusat setiap client dengan sistem login pada masing-masing pengguna memberikan alternatif penyimpanan pribadi secara terpusat dengan sumberdaya yang telah disediakan oleh server, dengan adanya server terpusat user dimudahkan dalam hal menyimpan file, baik itu tugas ataupun file project tanpa takut file tertukar dengan user lain, sedangkan tidak adanya limitasi website yang tidak boleh diakses pada jam-jam tertentu seperti jam produktif belajar dapat membuat fokus belajar siswa berkurang,dengan adanya management bandwidth melakukan manajemen pembagian kecepatan koneksi internet secara merata pada masing-masing client. dengan menggunakan metode layer7 protocol, dan Address List sebagai sarana limitasi akses ke website tertentu serta linux Ubuntu sebagai sarana server terpusat dan juga ditambahkannya manajemen hotspot sebagai sarana koneksi internet wireless untuk siswa dengan sistem autentikasi pribadi tanpa menggunakan password konvensional didapatkan hasil server domain controller bersifat lokal dan tidak bisa diakses oleh pihak diluar jaringan,pembagian bandwidth internet untuk siswa sebesar maksimal 1024Kbps mempunyai kecepatan rata-rata 700-1024Kbps, sedangkan untuk pemblokiran website tertentu seperti youtube,facebook,instagram,dan lain-lain dibatasi pada metode layer7 protocol dengan hasil semua situs yang diblokir tidak dapat dibuka, untuk pencatatan alamat ip dari game online dilakukan secara otomatis dan secara dinamis dengan metode Address List dengan hasil semua game yang tercacat tidak dapat diakses baik dari koneksi kabel ataupun non-kabel.
Kata Kunci: Samba, Domain Controller, Mikrotik, Bandwidth Management
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Yi, Cheng, Hongwen Xing, Qiaoyun Wu, Yuan Zhang, Mingqiang Wei, Bo Wang e Laishui Zhou. "Automatic Detection of Cross-Shaped Targets for Laser Scan Registration". IEEE Access 6 (2018): 8483–500. http://dx.doi.org/10.1109/access.2018.2799841.
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Bezak, Eva, Kristin V. Carson-Chahhoud, Loredana G. Marcu, Magdalena Stoeva, Lenka Lhotska, Gilda A. Barabino, Fatimah Ibrahim et al. "The Biggest Challenges Resulting from the COVID-19 Pandemic on Gender-Related Work from Home in Biomedical Fields—World-Wide Qualitative Survey Analysis". International Journal of Environmental Research and Public Health 19, n. 5 (6 marzo 2022): 3109. http://dx.doi.org/10.3390/ijerph19053109.
Testo completoAbstract (sommario):
(1) Background: This paper aims to present and discuss the most significant challenges encountered by STEM professionals associated with remote working during the COVID-19 lockdowns. (2) Methods: We performed a qualitative analysis of 921 responses from professionals from 76 countries to the open-ended question: “What has been most challenging during the lockdown for you, and/or your family?” (3) Findings: Participants reported challenges within the immediate family to include responsibilities for school, childcare, and children’s wellbeing; and the loss of social interactions with family and friends. Participants reported increased domestic duties, blurred lines between home and work, and long workdays. Finding adequate workspace was a problem, and adaptations were necessary, especially when adults shared the same setting for working and childcare. Connectivity issues and concentration difficulties emerged. While some participants reported employers’ expectations did not change, others revealed concerns about efficiency. Mental health issues were expressed as anxiety and depression symptoms, exhaustion and burnout, and no outlets for stress. Fear of becoming infected with COVID-19 and uncertainties about the future also emerged. Pressure points related to gender, relationship status, and ethnicities were also evaluated. Public policies differed substantially across countries, raising concerns about the adherence to unnecessary restrictions, and similarly, restrictions being not tight enough. Beyond challenges, some benefits emerged, such as increased productivity and less time spent getting ready for work and commuting. Confinement resulted in more quality time and stronger relationships with family. (4) Interpretation: Viewpoints on positive and negative aspects of remote working differed by gender. Females were more affected professionally, socially, and personally than males. Mental stress and the feeling of inadequate work efficiency in women were caused by employers’ expectations and lack of flexibility. Working from home turned out to be challenging, primarily due to a lack of preparedness, limited access to a dedicated home-office, and lack of previous experience in multi-layer/multi-scale environments.
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Song, Liang, e Dimitrios Hatzinakos. "Architecture of Wireless Sensor Networks with Mobile Sinks: Multiple Access Case". International Journal of Distributed Sensor Networks 3, n. 3 (luglio 2007): 289–310. http://dx.doi.org/10.1080/15501320601062130.
Testo completoAbstract (sommario):
We propose to develop Wireless Sensor Networks with Mobile Sinks (MSSN), under high sensor node density, where multiple sensor nodes need to share one single communication channel in the node-to-sink transmission. By exploiting the tradeoff between the successful information retrieval probability and the nodes energy consumption, a number of multiple nodes transmission scheduling algorithms are proposed. Both optimal and suboptimal algorithms, which exhibit exponential and linear complexity respectively, are discussed under the desired application. Computer simulations show that suboptimal algorithms perform nearly as good as the optimal one. The study leads to the cross-layer Wireless Link layer design for MSSN.
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Wang, Zhengkang, Jianming Shang, Kuanlin Mu, Song Yu e Yaojun Qiao. "Stable Single-Longitudinal-Mode Fiber Laser With Ultra-Narrow Linewidth Based on Convex-Shaped Fiber Ring and Sagnac Loop". IEEE Access 7 (2019): 166398–403. http://dx.doi.org/10.1109/access.2019.2953886.
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Hassan, Abu Sufian Abdallah, Hassan Yousif Ahmed, Hilal A. Fadhil, Medien Zeghid, Abdellah Chehri e Somia A. Abd El-Mottaleb. "Implementation of Shared Laser–LED Sources in a Free Space Optics (FSO) Network under Environmental Impact". Electronics 12, n. 4 (6 febbraio 2023): 801. http://dx.doi.org/10.3390/electronics12040801.
Testo completoAbstract (sommario):
This paper is devoted to evaluating the combined coherent and incoherent sources (CCIS) technique for different applications in the optical domain and future optical code division multiple access (OCDMA) networks. Spectral amplitude coding (SAC) has gained significant attention in optical processing systems due to its increased capabilities in dealing with multiple-access interference (MAI) efficiently. Fixed right shift (FRS) is adopted as a signature code in this study. Furthermore, performance analysis is studied in terms of bit error rate (BER) for the system using CCIS in both the free space optics (FSO) and sky mesh network using an aerial altitude platform system (AAPS). Simulation results confirmed that a CCIS design significantly improves system performance with moderate cost. An acceptable BER value of 10−9 at 1.25 Gbps data rate and 60 km, 38 km, and 6 km distances for the laser, CCIS, and LED sources, respectively, can be supported. In particular, at Q-factor ~4.5, the FSO ranges under low haze, moderate haze, and heavy haze are, respectively, 3.7 km, 2.5 km, and 1.5 km. The reason is that a CCIS design causes an increase in the effective transmitted power. It can be summarized that a CCIS design can provide reliable solutions and an affordable cost for future optical fiber and wireless network applications.
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Buckingham, Donna. "A Binding Separation: The New Zealand-Australia Partnership in Free Access to Law". International Journal of Legal Information 38, n. 3 (2010): 269–81. http://dx.doi.org/10.1017/s0731126500005874.
Testo completoAbstract (sommario):
While both New Zealand and Australia have a shared history, each tells a separate story of sovereignty. Both began as British colonies and, when Australia became a federation in 1901, there was opportunity for New Zealand to join. It chose not to do so. To use an image from Moori, New Zealand's indigenous language, it decided to paddle its own waka (canoe). A century and a bit later, the New Zealand Legal Information Institute (NZLII) is another iteration of that drive to differentiate, born of a hope that an indigenous online identity might help to build more comprehensive free access to its legal information.
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Blažek, Lukáš. "Sustainability of a shared economy". 11th GLOBAL CONFERENCE ON BUSINESS AND SOCIAL SCIENCES 11, n. 1 (9 dicembre 2020): 59. http://dx.doi.org/10.35609/gcbssproceeding.2020.11(59).
Testo completoAbstract (sommario):
Shared economy is a current concept associated with the sharing of human, physical and intellectual resources. The penetration of a shared economy into different sectors of human activity is often referred to as a prerequisite for further sustainable development. Thus, a shared economy is one of the basic pillars of sustainable development, as it helps the market to function better, raises awareness of prices and the quality of services, but also enables anyone to have better market access. It is necessary to monitor, research, analyze and focus on identifying positive as well as negative impacts. The speed of technological development has significantly exceeded the legislative, regulatory and tax frameworks, which is often the cause of tensions between old and new business models. In general, a balance between a degree of regulation and freedom is a desirable state of affairs, providing a clear framework and rules for a shared economy while allowing for its further development and change. However, there is no consensus among experts on how to achieve this balance. The tightening of the regulation of individual shared services or, on the contrary, the deregulation of traditional industries is most often mentioned. At the same time, there are critical voices pointing to the fact that a shared economy is the result of technological progress that cannot be suppressed or reversed by any regulation, so it should have its own special laws. Given the popularity and constant development of digital technologies along with consumer habits, it is very real that a shared economy will sooner or later affect almost all areas of business. In order to make the best use of its potential, it will be necessary to find a way to adapt to its development and influence it as needed. The paper deals with the above areas with a possible prediction and proposal for future development. Keywords: Shared Economy; Circular Economics; Sustainability; Consumption; Externality
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Ballester Martínez, Blanca. "La forja jurisprudencial del principio de transparencia". Teoría y Realidad Constitucional, n. 28 (1 giugno 2011): 381. http://dx.doi.org/10.5944/trc.28.2011.6965.
Testo completoAbstract (sommario):
Regulation 1049/2001 establishes and shapes the right of access to documents in the European Union. This right is limited by a series of colliding principles and rights, such as privacy of personal data, ‘ordre public’ or commercial interests. The European Court of Justice, through rulings by each one of its two Courts (the General Court and the European Court), has shaped and generally extended the scope of Regulation 1049/2001, increasing transparency in the institutions. However, there is no clear case-law trend as regards access to documents, since rulings often contradict each other and precedents are of relatively little value. Recent rulings, such as those given to the Borax and Bavarian Lager cases, seem to restrict public access to documents in the institutions by placing access to documents under other values such as privacy and data protection. This trend seems again to contradict what the Lisbon Treaty and the European Charter of Fundamental Rights have just introduced: a higher consideration of access to documents and a clear commitment with institutional transparency. This paper aims at giving a clear overview of the evolution and state of play of the right of public access to documents in the European legislation and case law. By analyzing the latest legal and jurisprudential developments, it can be concluded that law and case law do not seem to go hand in hand yet and seem to contradict each other. Immediate and further developments should be watched with a careful eye, as these will shape the post-Lisbon concept of access to documents. Consequently, essential principles such as transparency and data protection might undergo as well important changes.El Reglamento 1049/2001 consagra y configure el derecho de acceso público a documentos en la Unión Europea. Este derecho está limitado por ciertos bienes jurídicos en conflicto, como la privacidad de los datos personales, el orden público o los intereses comerciales. El Tribunal de Justicia de la Unión Europea, a través de las sentencias emanadas de sus dos instancias, ha pulido y en general extendido el campo de aplicación del Reglamento 1049/2001, aumentando la transparencia en las instituciones. Sin embargo, no hay una línea jurisprudencial clara al respecto, dado que las sentencias a menudo se contradicen entre sí y los precedentes jurisprudenciales parecen tener escaso valor en los asuntos posteriores. Algunas sentencias recientes, como las recaídas en los asuntos Borax y Bavarian Lager, parecen por el contrario restringir el derecho de acceso a documentos, dado que hacen prevalecer otros bienes jurídicos como la privacidad o la protección de datos. Esta última tendencia parece contradecir al Tratado de Lisboa y a la Carta Europea de Derechos Fundamentales, puesto que éstos han introducido una mayor consideración al derecho de acceso a documentos con el fin de aumentar la transparencia institucional. Este artículo busca procurar una panorámica general de la evolución y el estado actual del derecho de acceso público a los documentos tanto en la legislación como en la jurisprudencia europeas. Del análisis tanto de las novedades legislativas y jurisprudenciales al respecto se deduce que ambas no parecen ir a la par, sino que llegan incluso a contradecirse. El desarrollo futuro tanto de la ley como de la jurisprudencia deberán ser objeto de estudio detallado, dado que serán determinantes en la configuración del derecho de acceso a documentos tras el Tratado de Lisboa. Como consecuencia de esto, puede que ciertos principios también fundamentales, como la transparencia o la protección de datos, sufran importantes cambios en un futuro inmediato.
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Jaber, Zaid Hashim, Dheyaa Jasim Kadhim e Ahmed Sabah Al-Araji. "Medium access control protocol design for wireless communications and networks review". International Journal of Electrical and Computer Engineering (IJECE) 12, n. 2 (1 aprile 2022): 1711. http://dx.doi.org/10.11591/ijece.v12i2.pp1711-1723.
Testo completoAbstract (sommario):
<p><span>Medium access control (MAC) protocol design plays a crucial role to increase the performance of wireless communications and networks. The channel access mechanism is provided by MAC layer to share the medium by multiple stations. Different types of wireless networks have different design requirements such as throughput, delay, power consumption, fairness, reliability, and network density, therefore, MAC protocol for these networks must satisfy their requirements. In this work, we proposed two multiplexing methods for modern wireless networks: Massive multiple-input-multiple-output (MIMO) and power domain non-orthogonal multiple access (PD-NOMA). The first research method namely Massive MIMO uses a massive number of antenna elements to improve both spectral efficiency and energy efficiency. On the other hand, the second research method (PD-NOMA) allows multiple non-orthogonal signals to share the same orthogonal resources by allocating different power level for each station. PD-NOMA has a better spectral efficiency over the orthogonal multiple access methods. A review of previous works regarding the MAC design for different wireless networks is classified based on different categories. The main contribution of this research work is to show the importance of the MAC design with added optimal functionalities to improve the spectral and energy efficiencies of the wireless networks.</span></p>