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1
ZIMMERMANN, MARIO MENDES DE O. "LUAPS - LUA PUBLISH-SUBSCRIBE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8718@1.
Full textAbstract:
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>Sistemas publish-subscribe são definidos por seu modelo
básico de comunicação. No entanto, a maior parte dos
sistemas publish-subscribe existentes
incorpora outros mecanismos em sua implementação. Este
trabalho
busca um melhor entendimento de sistemas publish-
subscribe, definindo
uma arquitetura onde diferentes camadas agrupam decisões e
construções
relacionadas. Baseado nesta arquitetura, descrevemos um
sistema desenvolvido
em Lua que utiliza uma tabela hash distribuída como base.
O sistema
se diferencia dos sistemas publish-subscribe monolíticos e
tem como
foco generalidade, flexibilidade e extensibilidade.<br>Publish-subscribe systems are defined by its communication
model.
However, most of the existent publish-subscribe systems
incorporate
other mechanisms in their implementation. This work seeks
a better
understanding of publish-subscribe systems, defining an
architecture where
different layers group related decisions and constructions.
Based on this
architecture, we describe a system developed in Lua that
uses a distributed
hash table as its base. The system differs in its
architecture from
monolithic publish-subscribe systems and focus on
generality, flexibility and
extensibility.
2
Haikara, Jussi. "Publish-Subscribe Communication for CoAP." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209350.
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Low powered Internet of Things solutions such as wireless sensor networks often operate under heavy constraints, and require special care in the design of their communication models. This project consists of implementing and evaluating the proposed IETF draft of the publish-subscribe communication model for the Constrained Application Protocol (CoAP) on a wireless sensor network (WSN) using the Contiki operating system.<br>Lågenergilösningar för Internet of Things såsom trådlösa sensornätverk opererar ofta under kraftiga begränsningar, och kräver speciell omtanke i utformningen av sina kommunikationsmodeller. Detta projekt består av att implementera och utvärdera utkastet till IETFstandarden för kommunikationsmodellen publish-subscribe för Constrained Application Protocol (CoAP) i ett trådlöst sensornätverk som brukar operativsystemet Contiki.
3
Vargas, Herring Luis Carlos. "Integrating databases and publish/subscribe." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609151.
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4
Ion, Mihaela. "Security of Publish/Subscribe Systems." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/368098.
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The increasing demand for content-centric applications has motivated researchers to rethink and redesign the way information is stored and delivered on the Internet. Increasingly, network traffic consists of content dissemination to multiple recipients. However, the host-centric architecture of the Internet was designed for point-to-point communication between two fixed endpoints. As a result, there is a mismatch between the current Internet architecture and current data or content-centric applications, where users demand data, regardless of the source of the information, which in many cases is unknown to them.
Content-based networking has been proposed to address such demands with the advantage of increased efficiency, network load reduction, low latency, and energy efficiency. The publish/subscribe (pub/sub) communication paradigm is the most complex and mature example of such a network. Another example is Information Centric Networking (ICN), a global-scale version of pub/sub systems that aims at evolving the Internet from its host-based packet delivery to directly retrieving information by name. Both approaches completely decouple senders (or publishers) and receivers (or subscribers) being very suitable for content-distribution applications or event-driven applications such as instant news delivery, stock quote dissemination, and pervasive computing. To enable this capability, at the core of pub/sub systems are distributed routers or brokers that forward information based on its content. The basic operation that brokers need to perform is to match incoming messages or publications against registered interests or subscriptions.
Though a lot of research has focused on increasing the networking efficiency, security has been only marginally addressed. We believe there are several reasons for this. First of all, security solutions designed for point-to-point communication such as symmetric-key encryption do not scale up to pub/sub systems or ICN applications, mainly because publishers and subscribers are decoupled and it is infeasible for them to establish or to maintain contact and therefore to exchange keying material. In this thesis we analyse several such emerging applications like Smart Energy Systems, Smart Cities and eHealth applications that require greater decoupling of publishers and subscribers, and possible full decoupling.
Second, in large applications that run over public networks and span several administrative domains, brokers cannot be trusted with the content of exchanged messages. Therefore, what pub/sub systems need are solutions that allow brokers to match the content of publications against subscriptions without learning anything about their content. This task is made even more difficult when subscriptions are complex, representing conjunctions and disjunctions of both numeric and non-numeric inequalities. The solutions we surveyed were unable to provide publication and subscription confidentiality, while at the same time supporting complex subscription filters and keeping key management scalable.
Another challenge for publish/subscribe systems is enforcing fine-grained access control policies on the content of publications. Access control policies are usually enforced by a trusted third party or by the owner holding the data. However, such solutions are not possible for pub/sub systems. When brokers are not trusted, even the policies themselves should remain private as they can reveal sensitive information about the data.
In this thesis we address these challenges and design a novel security solution for pub/sub systems when brokers are not trusted such that: (i) it provides confidentiality of publications and subscriptions, (ii) it does not require publishers and subscribers to share keys, (iii) it allows subscribers to express complex subscription filters in the form of general Boolean expressions of predicates, and (iv) it allows enforcing fine-grained access control policies on the data. We provide a security analysis of the scheme.
%We further consider active attackers that corrupt messages or try to disrupt the network by replaying old legitimate messages, or that the publishers and subscribers themselves could misbehave, and provide solutions for data integrity, authentication and non-repudiation.
Furthermore, to secure data caching and replication in the network, a key requirement for ICN systems and recently also of pub/sub systems that extended brokers with database functionality, we show how our solution can be transformed in an encrypted search solution able to index publications at the broker side and allow subscribers to make encrypted queries. This is the first full-fledged multi-user encrypted search scheme that allows complex queries. We analyse the inference exposure of our index using different threat models.
To allow our encrypted routing solution to scale up to large applications or performance constrained applications that require real-time delivery of messages, we also discuss subscription indexing and the inference exposure of the index.
Finally, we implement our solution as a set of middleware-agnostic libraries and deploy them on two popular content-based networking implementations: a pub/sub system called PADRES, and an ICN called CCNx. Performance analysis shows that our solution is scalable.
5
Ion, Mihaela. "Security of Publish/Subscribe Systems." Doctoral thesis, University of Trento, 2013. http://eprints-phd.biblio.unitn.it/993/1/Thesis.pdf.
Full textAbstract:
The increasing demand for content-centric applications has motivated researchers to rethink and redesign the way information is stored and delivered on the Internet. Increasingly, network traffic consists of content dissemination to multiple recipients. However, the host-centric architecture of the Internet was designed for point-to-point communication between two fixed endpoints. As a result, there is a mismatch between the current Internet architecture and current data or content-centric applications, where users demand data, regardless of the source of the information, which in many cases is unknown to them.
Content-based networking has been proposed to address such demands with the advantage of increased efficiency, network load reduction, low latency, and energy efficiency. The publish/subscribe (pub/sub) communication paradigm is the most complex and mature example of such a network. Another example is Information Centric Networking (ICN), a global-scale version of pub/sub systems that aims at evolving the Internet from its host-based packet delivery to directly retrieving information by name. Both approaches completely decouple senders (or publishers) and receivers (or subscribers) being very suitable for content-distribution applications or event-driven applications such as instant news delivery, stock quote dissemination, and pervasive computing. To enable this capability, at the core of pub/sub systems are distributed routers or brokers that forward information based on its content. The basic operation that brokers need to perform is to match incoming messages or publications against registered interests or subscriptions.
Though a lot of research has focused on increasing the networking efficiency, security has been only marginally addressed. We believe there are several reasons for this. First of all, security solutions designed for point-to-point communication such as symmetric-key encryption do not scale up to pub/sub systems or ICN applications, mainly because publishers and subscribers are decoupled and it is infeasible for them to establish or to maintain contact and therefore to exchange keying material. In this thesis we analyse several such emerging applications like Smart Energy Systems, Smart Cities and eHealth applications that require greater decoupling of publishers and subscribers, and possible full decoupling.
Second, in large applications that run over public networks and span several administrative domains, brokers cannot be trusted with the content of exchanged messages. Therefore, what pub/sub systems need are solutions that allow brokers to match the content of publications against subscriptions without learning anything about their content. This task is made even more difficult when subscriptions are complex, representing conjunctions and disjunctions of both numeric and non-numeric inequalities. The solutions we surveyed were unable to provide publication and subscription confidentiality, while at the same time supporting complex subscription filters and keeping key management scalable.
Another challenge for publish/subscribe systems is enforcing fine-grained access control policies on the content of publications. Access control policies are usually enforced by a trusted third party or by the owner holding the data. However, such solutions are not possible for pub/sub systems. When brokers are not trusted, even the policies themselves should remain private as they can reveal sensitive information about the data.
In this thesis we address these challenges and design a novel security solution for pub/sub systems when brokers are not trusted such that: (i) it provides confidentiality of publications and subscriptions, (ii) it does not require publishers and subscribers to share keys, (iii) it allows subscribers to express complex subscription filters in the form of general Boolean expressions of predicates, and (iv) it allows enforcing fine-grained access control policies on the data. We provide a security analysis of the scheme.
%We further consider active attackers that corrupt messages or try to disrupt the network by replaying old legitimate messages, or that the publishers and subscribers themselves could misbehave, and provide solutions for data integrity, authentication and non-repudiation.
Furthermore, to secure data caching and replication in the network, a key requirement for ICN systems and recently also of pub/sub systems that extended brokers with database functionality, we show how our solution can be transformed in an encrypted search solution able to index publications at the broker side and allow subscribers to make encrypted queries. This is the first full-fledged multi-user encrypted search scheme that allows complex queries. We analyse the inference exposure of our index using different threat models.
To allow our encrypted routing solution to scale up to large applications or performance constrained applications that require real-time delivery of messages, we also discuss subscription indexing and the inference exposure of the index.
Finally, we implement our solution as a set of middleware-agnostic libraries and deploy them on two popular content-based networking implementations: a pub/sub system called PADRES, and an ICN called CCNx. Performance analysis shows that our solution is scalable.
6
Skovronski, John. "An ontology-based publish-subscribe framework." Diss., Online access via UMI:, 2006.
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7
Naicken, Stephen Murugapa. "Trusted content-based publish/subscribe trees." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/38598/.
Full textAbstract:
Publish/Subscribe systems hold strong assumptions of the expected behaviour of clients and routers, as it is assumed they all abide by the matching and routing protocols. Assumptions of implicit trust between the components of the publish/subscribe infrastructure are acceptable where the underlying event distribution service is under the control of a single or multiple co-operating administrative entities and contracts between clients and these authorities exist, however there are application contexts where these presumptions do not hold. In such environments, such as ad hoc networks, there is the possibility of selfish and malicious behaviour that can lead to disruption of the routing and matching algorithms. The most commonly researched approach to security in publish/subscribe systems is role-based access control (RBAC). RBAC is suitable for ensuring confidentiality, but due to the assumption of strong identities associated with well defined roles and the absence of monitoring systems to allow for adaptable policies in response to the changing behaviour of clients, it is not appropriate for environments where: identities can not be assigned to roles in the absence of a trusted administrative entity; long-lived identities of entities do not exist; and where the threat model consists of highly adaptable malicious and selfish entities. Motivated by recent work in the application of trust and reputation to Peer-to-Peer networks, where past behaviour is used to generate trust opinions that inform future transactions, we propose an approach where the publish/subscribe infrastructure is constructed and re-configured with respect to the trust preferences of clients and routers. In this thesis, we show how Publish/Subscribe trees (PSTs) can be constructed with respect to the trust preferences of publishers and subscribers, and the overhead costs of event dissemination. Using social welfare theory, it is shown that individual trust preferences over clients and routers, which are informed by a variety of trust sources, can be aggregated to give a social preference over the set of feasible PSTs. By combining this and the existing work on PST overheads, the Maximum Trust PST with Overhead Budget problem is defined and is shown to be in NP-complete. An exhaustive search algorithm is proposed that is shown to be suitable only for very small problem sizes. To improve scalability, a faster tabu search algorithm is presented, which is shown to scale to larger problem instances and gives good approximations of the optimal solutions. The research contributions of this work are: the use of social welfare theory to provide a mechanism to establish the trustworthiness of PSTs; the finding that individual trust is not interpersonal comparable as is considered to be the case in much of the trust literature; the Maximum Trust PST with Overhead Budget problem; and algorithms to solve this problem.
8
Sun, Qixiang 1978. "Reliable multicast for publish/subscribe systems." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86517.
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9
Mühl, Gero. "Large-scale content based publish, subscribe systems." [S.l. : s.n.], 2002. http://elib.tu-darmstadt.de/diss/000274.
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10
Jerzak, Zbigniew. "XSiena: The Content-Based Publish/Subscribe System." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-24628.
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Just as packet switched networks constituted a major breakthrough in our perception of the information exchange in computer networks so have the decoupling properties of publish/subscribe systems revolutionized the way we look at networking in the context of large scale distributed systems. The decoupling of the components of publish/subscribe systems in time, space and synchronization has created an appealing platform for the asynchronous information exchange among anonymous information producers and consumers. Moreover, the content-based nature of publish/subscribe systems provides a great degree of flexibility and expressiveness as far as construction of data flows is considered.
However, a number of challenges and not yet addressed issued still exists in the area of the publish/subscribe systems. One active area of research is directed toward the problem of the efficient content delivery in the content-based publish/subscribe networks. Routing of the information based on the information itself, instead of the explicit source and destination addresses poses challenges as far as efficiency and processing times are concerned. Simultaneously, due to their decoupled nature, publish/subscribe systems introduce new challenges with respect to issues related to dependability and fail-awareness.
This thesis seeks to advance the field of research in both directions. First it shows the design and implementation of routing algorithms based on the end-to-end systems design principle. Proposed routing algorithms obsolete the need to perform content-based routing within the publish/subscribe network, pushing this task to the edge of the system. Moreover, this thesis presents a fail-aware approach towards construction of the content-based publish/subscribe system along with its application to the creation of the soft state publish/subscribe system. A soft state publish/subscribe system exposes the self stabilizing behavior as far as transient timing, link and node failures are concerned. The result of this thesis is a family of the XSiena content-based publish/subscribe systems, implementing the proposed concepts and algorithms. The family of the XSiena content-based publish/subscribe systems has been a subject to rigorous evaluation, which confirms the claims made in this thesis.
11
Bittner, Sven. "General Boolean Expressions in Publish-Subscribe Systems." The University of Waikato, 2008. http://hdl.handle.net/10289/2529.
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The increasing amount of electronically available information in society today is undeniable. Examples include the numbers of general web pages, scientific publications, and items in online auctions. From a user's perspective, this trend will lead to information overflow. Moreover, information publishers are compromised by this situation, as users have greater difficulty in identifying useful information. Publish-subscribe systems can be applied to cope with the reality of information overflow. In these systems, users specify their information interests as subscriptions and, subsequently, only matching information (event messages) is delivered; uninteresting information is filtered out before reaching users. In this dissertation, we consider content-based publish-subscribe systems, a sophisticated example of these systems. They perform the information-filtering task based on the content of provided information. In order to deal with high numbers of subscriptions and frequencies of event messages, publish-subscribe systems are realized as distributed systems. Advertisements---publisher specifications of potential future event messages---are optionally applied in these systems to reduce the internal distribution of subscriptions. Existing work on content-based publish-subscribe concepts mainly focuses on subscriptions and advertisements as pure conjunctive expressions. Therefore, subscriptions or advertisements using operators other than conjunction need to be canonically converted to disjunctive normal form by these systems. Each conjunctive component is then treated as individual subscription or advertisement. Unfortunately, the size of converted expressions is exponential in the worst case. In this dissertation, we show that the direct support of general Boolean subscriptions and advertisements improves the time and space efficiency of general-purpose content-based publish-subscribe systems. For this purpose, we develop suitable approaches for the filtering and routing of general Boolean expressions in these systems. Our approaches represent solutions to exactly those components of content-based publish-subscribe systems that currently restrict subscriptions and advertisements to conjunctive expressions. On the subscription side, we present an effective generic filtering algorithm, and a novel approach to optimize event routing tables, which we call subscription pruning. To support advertisements, we show how to calculate the overlap between subscriptions and advertisements, and introduce the first designated subscription routing optimization, which we refer to as advertisement pruning. We integrate these approaches into our prototype BoP (BOolean Publish-subscribe) which allows for the full support of general Boolean expressions in its filtering and routing components. In the evaluation part of this dissertation, we empirically analyze our prototypical implementation BoP and compare its algorithms to existing conjunctive solutions. We firstly show that our general-purpose Boolean filtering algorithm is more space- and time-efficient than a general-purpose conjunctive filtering algorithm. Secondly, we illustrate the effectiveness of the subscription pruning routing optimization and compare it to the existing covering optimization approach. Finally, we demonstrate the optimization effect of advertisement pruning while maintaining the existing overlapping relationships in the system.
12
Zhang, Yuanhui. "Evaluating a publish/subscribe proxy for HTTP." Thesis, KTH, Kommunikationssystem, CoS, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121282.
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With the increasingly high speed of the Internet and its wide spread usage, the current Internet architecture exhibits some problems. The publish/subscribe paradigm has been developed to support one of the most common patterns of communication. It makes “information” the center of communication and removes the “location-identity split” (i.e., that objects are at specific locations to which you must communicate with to access the object). In this thesis project a publish/subscribe network is built and then used in the design, implementation, and evaluation of a publish/subscribe proxy for today’s HTTP based communication. By using this proxy users are able to use their existing web browser to send both HTTP requests and Publish/Subscribe Internet Routing Paradigm (PSIRP) requests. A publish/subscribe overlay is responsible for maintaining PSIRP contents. The proxy enables web browser clients to benefit from the publish/subscribe network, without requiring them to change their behavior or even be aware of the fact that the content that they want to access is being provided via the publish/subscribe overlay. The use of the overlay enables a user’s request to be satisfied by any copy of the content, potentially decreasing latency, reducing backbone network traffic, and reducing the load on the original content server. One of the aims of this thesis is to make more PSIRP content available, this is done by introducing a proxy who handles both HTTP and PSIRP requests, but having received content as a result of an HTTP response it publishes this data as PSIRP accessible content. The purpose is to foster the introduction and spread of content based access.<br>Med allt högre Internetshastighet och dess utbredda användning, uppvisar den aktuella Internet-arkitekturen vissa problem. Publicera / prenumerera paradigm har utvecklats för att stödja en av de vanligaste mönstren för kommunikation. Det gör att "information" blir centrum av kommunikation och tar bort "plats-identitet split" (dvs att objekten är på specifika platser som du måste kommunicera med för att komma åt objektet). i detta examensarbete byggs ett publicera / prenumerera nätverk och sedan används i utformningen, genomförandet, och utvärdering av en publicera / prenumerera proxy för dagens HTTP-baserad kommunikation. Genom att använda denna proxy kan användare kan använda sin befintliga webbläsare för att skicka både HTTP-förfrågningar och publicera / Prenumerera Internet Routing Paradigm (PSIRP) begäran. En publicera / prenumerera överlagring är ansvarig för att upprätthålla innehåll av PSIRP. Fullmakten gör det möjligt för klienter av webbläsare att dra nytta av publicera / prenumerera nätverket, utan att kräva dem att ändra sitt beteende eller ens vara medvetna om det faktum att det innehållet som de vill komma åt tillhandahålls via publicera / prenumerera överlägg. Användningen av överlägget kan en användare begäran som skall uppfyllas av en kopia av innehållet, eventuellt minskande latens, vilket minskar trafiken stamnät, och minska belastningen på det ursprungliga innehållet servern. Ett av syftena med denna uppsats är att göra mer PSIRP innehåll tillgängligt och detta görs genom att införa en proxy som hanterar både HTTP och PSIRP förfrågningar, men har fått innehåll som en följd av en HTTP-svar offentliggörs denna data som PSIRP tillgängligt innehåll. Syftet är att främja införandet och innehållbaserade åtkomsten.
13
Simosa, Jorge D. (Jorge David). "A publish-subscribe implementation of network management." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85226.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 75-77).<br>As modern networks become highly integrated, heterogeneous, and experience exponential growth, the task of network management becomes increasingly unmanageable for network administrators and designers. The Knowledge Plane (KP) is designed to support a self-managing network, given the organizational constraints of network management, as well as to create synergy and exploit commonality among network applications. In this thesis, to build an Information Plane that is suitable to the requirements of the KP, we propose a publish/subscribe system that provides a clear and systematic framework for resolving tussles in the network. To evaluate the eectiveness of this design, we configured a network of PlanetLab nodes and conducted experiments involving a variety of le sizes and source-destination pairs. The results suggest that the system's performance is not only comparable to existing le transfer services, but that the system also introduces several performance gains that are unattainable with current network architectures.<br>by Jorge D. Simosa.<br>M. Eng.
14
Taherian, Salman. "State-based publish/subscribe for sensor systems." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612542.
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Detko, Adam. "Kybernetická bezpečnost v systémech typu publish-subscribe." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-412988.
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This thesis deals with data distribution service and is divided into three parts. The first part of this thesis focuses on theoretical knowledge of data distribution service. This section gradually introduces the model used in data distribution service, quality of service and the RTPS protocol, which was specially developed for the needs of data distribution service. The most comprehensive part of the theoretical part deals with security in data distribution service. At the end of the first part of this thesis, selected impelementations of data distribution service are introduced. The second part of this thesis deals with practical use of data distribution service, while OpenDDS implementation is chosen for the practical part. This part initially deals with the design of basic communication scenarios, followed by the design of complex communication scenarios. In the next chapters, within the practical part, the thesis is focused on verifyng security of the data distribution service selected implementation, design of security incidents and their subsequent simulation. Content of the final part of this thesis is the introduction of a tool designed for this thesis, which is used to implement selected types of attacks.
16
Rahimian, Fatemeh. "Enabling Internet-Scale Publish/Subscribe In Overlay Networks." Licentiate thesis, KTH, Programvaru- och datorsystem, SCS, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-43716.
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As the amount of data in todays Internet is growing larger, users are exposedto too much information, which becomes increasingly more difficult tocomprehend. Publish/subscribe systems leverage this problem by providingloosely-coupled communications between producers and consumers of data ina network. Data consumers, i.e., subscribers, are provided with a subscriptionmechanism, to express their interests in a subset of data, in order to be notifiedonly when some data that matches their subscription is generated by theproducers, i.e., publishers. Most publish/subscribe systems today, are basedon the client/server architectural model. However, to provide the publish/-subscribe service in large scale, companies either have to invest huge amountof money for over-provisioning the resources, or are prone to frequent servicefailures. Peer-to-peer overlay networks are attractive alternative solutions forbuilding Internet-scale publish/subscribe systems. However, scalability comeswith a cost: a published message often needs to traverse a large number ofuninterested (unsubscribed) nodes before reaching all its subscribers. Werefer to this undesirable traffic, as relay overhead. Without careful considerations,the relay overhead might sharply increase resource consumption for therelay nodes (in terms of bandwidth transmission cost, CPU, etc) and couldultimately lead to rapid deterioration of the system’s performance once therelay nodes start dropping the messages or choose to permanently abandonthe system. To mitigate this problem, some solutions use unbounded numberof connections per node, while some other limit the expressiveness of thesubscription scheme. In this thesis work, we introduce two systems called Vitis and Vinifera, fortopic-based and content-based publish/subscribe models, respectively. Boththese systems are gossip-based and significantly decrease the relay overhead.We utilize novel techniques to cluster together nodes that exhibit similarsubscriptions. In the topic-based model, distinct clusters for each topic areconstructed, while clusters in the content-based model are fuzzy and do nothave explicit boundaries. We augment these clustered overlays by links thatfacilitate routing in the network. We construct a hybrid system by injectingstructure into an otherwise unstructured network. The resulting structuresresemble navigable small-world networks, which spans along clusters of nodesthat have similar subscriptions. The properties of such overlays make theman ideal platform for efficient data dissemination in large-scale systems. Thesystems requires only a bounded node degree and as we show, through simulations,they scale well with the number of nodes and subscriptions and remainefficient under highly complex subscription patterns, high publication rates,and even in the presence of failures in the network. We also compare bothsystems against some state-of-the-art publish/subscribe systems. Our measurementsshow that both Vitis and Vinifera significantly outperform theircounterparts on various subscription and churn scenarios, under both syntheticworkloads and real-world traces.<br>QC 20111114
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Strihagen, Karl. "Evaluation of publish – subscribe protocols for vehicle communications." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217524.
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Vehicles connected to networks of other vehicles is one promising example of the Internet of Things (IoT). Companies operating fleets of vehicles can benefit from thepossibility to aggregate all of the information that is generated from this network inorder to optimise their logistics and operations. Underlying this network is the need fora communication link that can connect distributed vehicles and efficient protocols tomanage the transmission of information. For vehicles, the cellular network is the best communication infrastructure available.Since cellular usage has a monetary cost that is proportional to data use, this thesisevaluates three protocols (MQTT, MQTT-SN and AMQP) in terms of how much datathey use during typical scenarios with regard to communications patterns and payload.Three different payload sizes were used to simulate different message types, and thepackage loss rate on the communication link was varied from 0% to 30% to bettersimulate real world conditions. The results showed that for small payload sizes the overhead can be the same order ofmagnitude as the payload and MQTT-SN performs significantly better than bothMQTT and AMQP. However, for larger payloads, this effect diminishes. For the largerpayload MQTT-SN actually consumed more data than the other two protocols. Underthe more lossy conditions tested there are some problems running experiments, such asthe underlaying TCP connection breaking in some cases and the time to complete thetask becomes very long. MQTT and AMQP generally performed about the same inmost aspects in the tests, with the exception of how they handle TCPacknowledgements.<br>Fordon som är anslutna till ett nätverk är en lovande applikation av sakernas internt (eng.Internet of Things). För företag vars kärnverksamhet involverar användandet av fordonkan den information som fordonen generar användas till att förbättra verksamheten. Föratt kunna använda nätverket krävs en kommunikationslänk som ansluter fordonet, samtett kommunikationsprotokoll för att förmedla information. För fordon är mobilnätet den bästa tillgängliga kommunikationslänken för att ansluta demtill internet. Att använda mobilnätet kostar pengar i proportion till den datamängd somanvänds, därför behandlas i denna rapport dataåtgången för tre protokoll, AMQP, MQTToch MQTT-SN. För dessa testar vi tre olika storlekar på nyttodata för att göra testerna merverklighetstrogna för typiska användningssituationer, testar vi dessa under inverkan avpaketförluster mellan 0% till 30% på nätverket. Resultaten från testerna visar att för små storlekar på nyttodata är MQTT-SN det protokollsom konsumerar minst data. För större storlekar på nyttodata är dataanvändningen förAMQP och MQTT ungefär likvärdiga i dataanvändning medans MQTT-SN användermer. Vid höga nivåer av paketförluster tog testerna lång tid och det var inte ovanligt attTCP anslutningen bröts. AMQP och MQTT hade överlag ganska lika beteenden, dockmed undantaget hantering av TCP:s leveranskvittens.
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RUBINSZTEJN, HANA KARINA SALLES. "CONTEXT-BASED CONTENT ADAPTATION FOR PUBLISH/SUBSCRIBE SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11494@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>Serviços para disseminação de informações (serviços push)
têm sido amplamente utilizados, em particular para
aplicações envolvendo usuários móveis. Estes serviços
geralmente atendem a dispositivos com recursos bem
diferenciados e em contextos de execução (conectividade
sem fio, reserva de energia, etc.) distintos, fazendo
necessário adaptar o conteúdo difundido dinamica- e
individualmente para cada cliente. Uma vez que muitas
adaptações de conteúdo envolvem operações custosas e
demandam alto poder de processamento, estas não devem ser
realizadas nos clientes móveis. Por outro lado, executar
no servidor, as adaptações para cada cliente móvel, torna-
se pouco eficiente e escalável. Assim, em tais serviços,
é comum utilizar-se intermediários dedicados às
adaptações de conteúdo (de acordo com o contexto) dos
clientes. Comunicação assíncrona, como publish/subscribe,
é considerada por muitos como a mais apropriada para este
tipo de serviço. Por outro lado, sistemas para adaptação
de conteúdo sensível a contexto não dão suporte a este
tipo de comunicação, até porque a adaptação precisa ser
individual, e portanto conflita com o paradigma de
comunicação um-para-muitos. Neste trabalho apresentamos
uma arquitetura para sistemas publish/subscribe com
adaptação sensível a contexto, que utiliza um algoritmo
que otimiza a adaptação de conteúdo para grandes
conjuntos de clientes de uma difusão.<br>Services for information dissemination (push services) are
being
widely used, in particular for applications involving
mobile users. These
services generally serve devices with diferent resources
and with distinct
execution contexts (wireless connectivity, energy source,
etc.), making it
necessary to adapt disseminated content individual and
dynamically for
each client. Since many content adaptations involve costly
operations and
demand high processing power, these should not be executed
at the mobile
clients. On the other hand, it is neither efficient nor
scalable to execute
the adaptations for each mobile client at the server. Thus,
in such services,
it is common to use proxies dedicated to content
adaptations (based on
the context) of clients. Asynchronous communication, such
as publish/-
subscribe, is considered the most appropriate form of
communication for
this type of service. On the other hand, systems for
context-aware content
adaptation do not support this type of communication. In
this thesis we
present an architecture for publish/subscribe systems with
context-aware
content adaptation, that uses an algorithm that optimizes
the content
adaptation for large sets of clients.
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Huang, Jessica Yu-Tien 1981. "Solving Bluetooth deficiencies through publish and subscribe systems." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28402.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.<br>Includes bibliographical references (p. 85-87).<br>Research in pervasive computing aims to fully integrate computing devices into our everyday environments in a seamless and efficient manner. Wireless technology such as Bluetooth takes us a step closer by replacing traditional cable connections with a more searnless communication transport, adding mobility and more human-centric computation. However, if we are to fully integrate this technology, we must first address some of its shortcomings, particularly those with respect to areas with a high density of Bluetooth devices. Four of these shortcomings: susceptibility to anonymous attacks, poor power management, synchrony requirement, and lack of friendships stem from the tight coupling of device interactions during the discovery protocol. One solution to this problem uses the advantages of publish and subscribe systems to decouple this interaction between smart mobile devices. Available devices can announce their availability to a central controller while devices interested in finding others can announce their interests. When a match occurs, the controller notifies both parties and provides information on how they can form a direct connection. This solution preserves the functionality of the Bluetooth connection protocol while circumventing the four shortcomings. The assumptions it makes are reasonable when placed in a the context of personal computing environment. Future considerations include optimizations that utilize caching, improvements on performance, increases in system capacity, and solutions for including dumb devices.<br>by Jessica Yu-Tien Huang.<br>M.Eng.
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Beckler, Kendra K. "Improved caching strategies for publish/subscribe internet networking." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/100334.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, February 2015.<br>Cataloged from PDF version of thesis. "September 2014."<br>Includes bibliographical references (pages 70-73).<br>The systemic structure of TCP/IP is outdated; a new scheme for data transportation is needed in order to make the internet more adaptive to modern demands of mobility, information-driven demand, ever-increasing quantity of users and data, and performance requirements. While an information centric networking system addresses these issues, one required component for publish subscribe or content-addressed internet networking systems to work properly is an improved caching system. This allows the publish subscribe internet networking to dynamically route packets to mobile users, as an improvement over pure hierarchical or pure distributed caching systems, To this end, I proposed, implemented, and analyzed the workings of a superdomain caching system. The superdomain caching system is a hybrid of hierarchical and dynamic caching systems designed to continue reaping the benefits of the caching system for mobile users (who may move between neighboring domains in the midst of a network transaction) while minimizing the latency inherent in any distributed caching system to improve upon the content-addressed system.<br>by Kendra K. Beckler.<br>M. Eng.
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Toy, Kimberly L. "Client-side optimizations for mobile publish subscribe systems." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106384.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 67-68).<br>Smartphones can provide a great deal of information about their users using numerous built-in sensors, such as location, local weather conditions, or current method of travel. This information has the potential to be relevant to other users, allowing them to be alerted about pertinent events in real-time, such as knowing where their family members are. This thesis proposes a design for a publish-subscribe system aimed to support sharing sensor data between mobile clients, where users can specify complex subscriptions over sensor data generated by other phones and receive alerts when a relevant event occurs. We present a number of client-side optimizations for collecting sensor data on the mobile device and communicating that data with the publish subscribe server efficiently, in order to reduce battery usage and data transmission. We then perform an evaluation of these optimizations, discuss design tradeoffs, and show which scenarios the optimizations perform best in.<br>by Kimberly L. Toy.<br>M. Eng.
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Alqaoud, Ahmed. "Publish/subscribe scientific workflow interoperability framework (PS-SWIF)." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54232/.
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Different or similar workflow systems, hosted anywhere on a network, written in any language and running on different operating systems, can easily use the full range of PS-SWIF tools to interoperate with each other. The PS-SWIF approach provides interoperability among a wide range of scientific workflow systems.
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Ye, Yifan. "Towards reducing bandwidth consumption in publish/subscribe systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285063.
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Efficient data collection is one of the key research areas for 5G and beyond, since it can reduce the network burden of transferring massive data for various data analytics and machine learning applications. Specifically, 5G offers great support for massive deployment of IoT devices, and the number of IoT devices is exploding.There are mainly two complementary ways for achieving efficient data collection: one is integrating data processing into the collection process via e.g. data filtering, aggregation; the other one is reducing the amount of the data needs to be transferred via e.g. data compression/approximation.In this thesis, efficient data collection is studied from the mentioned two perspectives. In particular, we introduce enhanced syntax and functionalities to the message queueing telemetry transport (MQTT) protocol, such as data filtering and data aggregation. Furthermore, we enhance the flexibility of MQTT by supporting customized or user-defined functions to be executed in the MQTT broker, and thus data processing in the broker will not be constrained to the predefined processing functions. Lastly, dual prediction is studied for reducing the data transmissions by maintaining the same learning model on both sides of the sender and receiver. In particular, we study and prototype least mean square (LMS) as the dual prediction algorithm. Our implementations are based on MQTT and the benefits are shown and evaluated via experiments using real IoT data.<br>Effektiv datainsamling är ett av de viktigaste forskningsområdena för 5G och därefter, eftersom det kan minska nätbördan för att överföra massiva data för olika dataanalyser och maskininlärningsapplikationer. Specifikt erbjuder 5G bra stöd för massiv distribution av IoT-enheter, och antalet IoT-enheter exploderar.Det finns huvudsakligen två komplementära sätt att uppnå effektiv datainsamling: ett är att integrera databehandling i insamlingsprocessen via t.ex. datafiltrering, aggregering; den andra minskar mängden data som behöver överföras via t.ex. datakomprimering / tillnärmning.I denna avhandling studeras effektiv datainsamling ur nämnda två perspektiv.I synnerhet introducerar vi förbättrad syntax och funktionalitet till meddelandekö telemetri-transportprotokollet (MQTT), till exempel datafiltrering och dataggregation. Dessutom förbättrar vi MQTT-flexibiliteten genom att stödja anpassade eller användardefinierade funktioner som ska köras i MQTT-mäklaren, och därför kommer databehandling i mäklaren inte att begränsas till de fördefinierade behandlingsfunktionerna. Slutligen studeras dubbla förutsägelser för att minska dataöverföringarna genom att bibehålla samma inlärningsmodell på båda sidornaav avsändaren och mottagaren. I synnerhet studerar och prototypar vi minst genomsnitt kvadrat (LMS) som den dubbla förutsägelsealgoritmen. Våra implementeringar är baserade på MQTT och fördelarna visas och utvärderas via experiment med verkliga IoT-data.
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MORABITO, FEDERICO GIUSEPPE. "Content-based publish/subscribe systems: architectures and algorithms." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/395.
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Publish/subscribe communication paradigm is an interaction paradigm suitable for a variety of large scale dynamic applications, requiring selective events diffusion or data notification: news delivery, stock quoting, on-line games, dissemination of multimedia contents, services and resources discovery, remote control of critical infrastructures and management of large scale systems are examples of systems requiring such reactive communication paradigm. Content-based publish/subscribe is the most promising version of publish/subscribe system: in such systems, users subscribe to content-based conditions, and will be notified about the published events that satisfy their expressed conditions. Content-based style subscriptions are highly expressive and flexible, permitting the users to specify complex filtering criteria along multiple dimensions of the events content. In contrast to their flexibility and expressiveness, scalable content-based publish/subscribe systems are difficult to implement and the proposed solutions are not always mature. In other words, one of the most fundamental requirement in the area of content-based pub/sub systems is to design scalable and efficient event dissemination mechanisms maintaining the expressiveness in the subscription language and the flexibility in the structures defining the events. In addition, most of existing pub/sub systems assume that actors involved in the subscriptions management have global knowledge about active subscriptions. This assumption limits the scalability of the existing approaches when they are dealing with large scale and dynamical systems. In this thesis, we research for algorithms and techniques that permit to build content-based pub/sub systems over efficient data dissemination structures.
The thesis consists on different kind of contributions.
First of all, a global and systematic analysis of the functionalities of the event service has been produced, critically describing the current solutions, the strengths and the weaknesses of the existing approaches.
In the second part, we propose innovative algorithms and architectures for pub/sub systems. We introduce novel approaches for content-based pub/sub systems, guaranteeing the expressiveness for any application domain and maintaining the scalability with respect to the number of participants and to the number subscriptions. The clustering functionality is designed to match application-level multicast techniques with content-based routing of events. We introduce clustering mechanisms (hierarchical and not hierarchical algorithms) in the event service to dynamically identify groups of users with similar preferences and to adapt these groups in the context of content-based publish/subscribe systems. One of the main feature of the proposed mechanism is the use of the system state knowledge sharing by system nodes, with the goal of limiting the system overhead in terms of computing, bandwidth and storage resources.
Gossiping and probabilistic techniques represent a potential and open research field that has been analyzed and described within this work. In high dynamical large scale systems, the dynamic and unpredictable behavior of the nodes can cause problems to be resolved with approaches more adaptive and robust to the fast and frequent system changes. An innovative solution for pub/sub systems is proposed relying on an unstructured overlay network where a variant of subscriptions flooding-based algorithm is adopted to face with highly dynamical environments.
Last contribution consists of examples of real applications that exploit the potentialities of the publish-subscribe paradigm model. We provide architectures based on the pub/sub models in the field of the infrastructures for monitoring critical systems and of the infrastructures for context-aware applications.
Keywords: clustering, multicast dissemination, broadcast dissemination, collaborative p2p approaches, structured and unstructured overlay networks, distributed systems evaluation, architectures based on pub/sub models.
25
Araujo, João Paulo de. "A communication-efficient causal broadcast publish/subscribe system." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS081.
Full textAbstract:
La Publication/Abonnement (Publish/Subscribe, Pub/Sub) est un paradigme qui permet aux nœuds d'un système distribué de diffuser des informations de manière asynchrone. Cette thèse s'intéresse aux systèmes de Pub/Sub basés sur des sujets (topic-based), en adressant les problèmes de performances et de contention existant dans plusieurs approches reposant sur des arbres. Les solutions proposées utilisent la construction d'arbres couvrants regroupant les abonnés et dont les racines sont les émetteurs. Les arbres associés à différentes sources sont organisés différemment. La première contribution de la thèse propose un protocole de diffusion causal agrégeant des messages et dans lequel aucun temporisateur n'est nécessaire. Le protocole regroupe les messages en un seul message sans utiliser des temporisateurs en tirant parti du délai de livraison supplémentaire imposé à un nœud lorsque les messages sont reçus en dehors de l'ordre causal ainsi que des intersections existantes entre des arbres couvrants. La deuxième contribution est un système de Pub/Sub par sujet, VCube-PS, qui assure l'ordre de traitement causal des messages publiés sur un même sujet et gère efficacement la publication de messages sur des sujets très populaires ("hot topics"). Les résultats des simulations confirment que le protocole d'agrégation causale proposé réduit le trafic réseau ainsi que des latences de livraison, en limitant la contention de messages. Comparé à une approche utilisant un seul arbre par sujet, VCube-PS repartit mieux la charge lors de publications massives sur des "hot topic"<br>The Publish/Subscribe (Pub/Sub) paradigm enables nodes of a distributed system to disseminate information asynchronously. This thesis investigates how to provide a communication-efficient topic-based Pub/Sub system by addressing the problems of traffic overhead and message contention, present in several tree-based solutions. The proposed contributions build distributed spanning trees on top of a hypercube-like topology, such that the source of each message is the root of its own dynamically built spanning tree. Trees rooted at different nodes are differently organized. Initially, it is proposed a causal broadcast protocol which reduces network traffic by aggregating messages without the use of timers. It exploits the causal relation between messages and path intersections between different trees. Different from existing timer-based approaches, it does not increase delivery latency. The second contribution is a topic-based Pub/Sub system, VCube-PS, which ensures causal delivery order for messages published to the same topic and efficiently supports publication of messages to "hot topics'', i.e., topics with high publication rates. Simulation results confirm that the proposed causal aggregation protocol reduces network traffic as well as delivery latencies since there is less message contention. Compared to an approach that uses one single tree per topic, VCube-PS performs better when there is a high publication rate per topic since it provides load balancing of publication
26
Zeidler, Andreas. "A Distributed Publish/Subscribe Notification Service for Pervasive Environments." Phd thesis, [S.l.] : [s.n.], 2005. http://elib.tu-darmstadt.de/diss/000519.
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Frommhold, Marvin, Sebastian Tramp, Natanael Arndt, and Niklas Petersen. "Publish and subscribe for RDF in enterprise value networks." Universität Leipzig, 2016. https://ul.qucosa.de/id/qucosa%3A15776.
Full textAbstract:
Sharing information securely between business partners and managing large supply chains effciently will be a crucial competitive advantage for enterprises in the near future. In this paper, we present a concept that allows for building value networks between business partners in a distributed manner. Companies are able to publish Linked Data which participants of the network can clone and subscribe to. Subscribers get noticed as soon as new information becomes available. This provides a technical infrastructure for business communication acts such as supply chain communication or master data management. In addition to the conceptual analysis, we provide an implementation enabling companies to create such dynamic semantic value networks.
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Liu, Chao. "Efficient Publish/Subscribe System over Mobile Ad-Hoc Network." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26485.
Full textAbstract:
Information dissemination is an important issue for mobile ad-hoc communities. This issue is very challenging due to the dynamic and fragile nature of the mobile ad-hoc networks, in which participants have limited computing resources and battery, intermittent network connections, and mobile tasks. To address the aforementioned issue, this thesis proposes an efficient semantics-based publish/subscribe strategy. In our proposed publish/subscribe system, distributed mobile participants are organized into clusters based on their location proximity. A compact semantics-based indexing scheme is provided to guide information flow. Intra- and inter- cluster routings are proposed to assist efficient propagation of event notifications. A comprehensive set of simulation experiments prove the effectiveness of the proposed scheme.
29
Chand, Raphaël. "Large scale diffusion of information in publish-subscribe systems." Nice, 2005. http://www.theses.fr/2005NICE4039.
Full textAbstract:
This work focuses on publish/subscribe systems, where producers publish information and consumers express their interests for certain types of information. The data is disseminated according to its nature and the interests of the consumers. Publish/subscribe systems have become a hot research topic, because the strong decoupling that they offer between the participants makes them well adapted to large scale distributed information systems. We first present a publish/subscribe system that we specifically designed to implement efficient and reliable distribution of structured xml content to very large populations of consumers. For that purpose, our system integrates several novel technologies, such as subscription aggregation. We have analyzed its efficiency by the means of various simulations and, to experiment with the conditions of the real internet, we have performed a large scale deployment in the planetlab testbed. Experimental results demonstrate that our system offers very good performance and salability under normal operation and can quickly recover from system failures. We then present a novel approach to building a publish/subscribe system based on the peer-to-peer paradigm. Our system features an extremely simple routing process. The price to pay for this simplicity is that routing may not be perfectly accurate. However, by organizing the peers in "semantic communities'', i. E. , by organizing them according to their interests with adequate proximity metrics, we can minimize the routing inaccuracy. Experimental results demonstrate that the routing process is indeed very accurate and highly efficient in the presence of large consumer populations<br>Cette these est consacree a l'etude de reseaux de type publication/abonnement dans lesquels des producteurs publient de l'information a l'intention de consommateurs. Les donnees sont diffusees selectivement en fonction de leur nature et des interets des consommateurs. Les reseaux de ce type sont devenus un theme de recherche tres populaire car ils offrent un grand decouplage entre les elements du systeme, permettant de passer aisement a l'echelle. Dans un premier temps, nous presentons un systeme de type publication/abonnement que nous avons specialement concu pour la diffusion efficace et fiable de documents xml a large echelle. Notre systeme integre plusieurs technologies et algorithmes novateurs, tels que l'agregation de souscriptions. Nous avons realise de nombreuses simulations et nous avons deploye notre systeme sur la plate-forme experimentale mondiale planetlab. Les resultats montrent que notre systeme est efficace et passe aisement a l'echelle, et est capable de se reconstituer rapidement suite a des pannes de liens ou de routeurs. Dans un deuxieme temps, nous proposons une approche originale pour concevoir un systeme de type publication/abonnement. Notre systeme est base sur le concept pair-a-pair. La principale innovation est l'utilisation d'un protocole de routage extremement simple. Il en resulte une certaine perte de precision, que nous pouvons cependant minimiser en organisant les pairs en fonction de leurs interets dans des ''communautes semantiques'', au moyen de metriques de proximite adequates. L'evaluation experimentale montre que le routage est effectivement precis et tres efficace en presence de grandes populations de consommateurs
30
Tanner, Andreas. "Distributed resource management with monetary incentives." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976429969.
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Zhang, Xin, and 张昕. "Gossip-based publish-subscribe systems in peer-to-peer networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208013.
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Peer-to-peer (P2P) paradigm, for its scalability and low cost management, is widely used in today’s network. Based on the typical designs for request/response services, a lot of efforts have been made to support publish-subscribe services in P2P networks. Gossip-based publish-subscribe system, which is commonly used in unstructured P2P networks, can provide great flexibility in query language and does not require special efforts on maintaining topology. The purpose of our work is to investigate effective and efficient mechanisms to build gossip-based publish-subscribe systems in unstructured P2P networks. Specifically, the probabilistic bi-quorum system (PBQS), for its assurance in effectiveness, becomes the object of our study.
Uniform sampling is a fundamental tool to construct PBQS. By adopting uniform sampling, PBQS provides a bound on the likelihood that data messages will find a copy of the subscription. A random walk of length O(log n) is commonly used to gain a uniform sample on an expander graph of size n. To obtain a multitude of uniform samples thus requires an equivalent number of random walks of length O(log n) each. A number of works have relied on the Chernoff bound to analytically reduce the overhead needed to obtain a multitude of uniform samples. Besides, researchers have also shown that it is not necessary to replicate both data and query on uniformly chosen nodes. Alternatively, BubbleStorm performs controlled flooding on a constructed overlay to build PBQS. BubbleStorm does not require nodes forming a bubble to be uniformly chosen at random, and the probabilistic bound computed by BubbleStorm is different from uniform sampling based PBQS.
In this thesis, we first show that the Chernoff bound on the statistical properties of samples collected from a random walk does not help in selecting uniformly random nodes. We then re-examine the role of uniform sampling in PBQS, and found that when multiple data answer a single subscription, it is sufficient and necessary for each data to be distributed uniformly at random. Looking into BubbleStorm, we examine more closely the probabilistic bound provided by this system. We found that, unlike uniform sampling based PBQS, the bubble intersection in BubbleStorm is distance dependent. Given a specific pair of publisher-subscriber, the data may never find the subscription. We further investigate the topology construction and found that re-creating topology prior to each controlled flooding or keeping topology with high degree of churn can help alleviate the distance dependency problem. We arrive at the conclusion that BubbleStorm construction is equivalent to caching of random walks. We show that re-using this cache to obtain samples over time leads to degradation of uniformity of the samples. We evaluate topology re-wiring as a simple method to keep the cache fresh, thereby benefiting from the low latency of controlled flooding without degrading the uniformity of samples over time.<br>published_or_final_version<br>Electrical and Electronic Engineering<br>Master<br>Master of Philosophy
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Wendt, Ivam Guilherme. "PSElastic : um modelo de elasticidade multinível para Brokers Publish/Subscribe." Universidade do Vale do Rio dos Sinos, 2017. http://www.repositorio.jesuita.org.br/handle/UNISINOS/6294.
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Previous issue date: 2017-02-23<br>CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>A Internet das Coisas (IoT - Internet of Things) é considerada a próxima grande evolução na era da computação após a Internet. Na Internet das Coisas muitos objetos que nos rodeiam serão conectados em redes e se comunicarão entre sí sem auxílio ou intervenção humana. Implementações de grande escala têm potencial para criar um enorme tráfego agregado. Muitas vezes Brokers ou Intermediários, são utilizados para possibilitar esta comunicação machine-to-machine (M2M), utilizando o modelo de comunicação Publish/- Subscribe que possui diversas bibliotecas particulares para uso na Internet das Coisas. Alguns trabalhos desenvolvidos pela comunidade visam tratar o desempenho no ambiente de Brokers Publish/Subscribe, no entanto impõem modificações e restrições quanto aos Brokers e arquitetura utilizada. Neste cenário, visando atender a necessidade de escalabilidade citada, é proposto um modelo de elasticidade chamado PSElastic. PSElastic fornece um modelo de elasticidade multinível para Brokers Publish/Subscribe, fazendo uso da elasticidade provida pela Computação em Nuvem, sem afetar o desempenho do sistema e sem a necessidade de investimentos ou ajustes por parte dos clientes e aplicações que fazem uso deste modelo. O modelo oferece a elasticidade de forma automática, reativa e multinível, onde multinível refere-se aos níveis de Broker e de Orquestrador do modelo. Buscando avaliar o modelo PSElastic foram definidos três cenários diferentes para a execução dos testes: Cenário 1, sem elasticidade; Cenário 2, elasticidade na camada de Brokers e Cenário 3, elasticidade multinível. Diferentes limites de réplicas de máquinas virtuais foram utilizados, assim como combinações de thresholds para avaliar o Tempo de Execução, quantidade de Mensagens por Segundo tratadas e a Eficiência na utilização dos recursos computacionais. PSElastic apresentou excelentes resultados ao reduzir em até 81,2% o tempo necessário para o tratamento de uma carga de dados e aumentar o throughput do ambiente com Broker Mosquitto de 54,95 mensagens por segundo (Mps) para 235,29 Mps e de 38,02 Mps para 202,02 Mps no ambiente com Broker RabbitMQ.<br>The Internet of Things (IoT) is considered the next big evolution in the computing era after the Internet. In Internet of Things many objects around us will be connected in networks and will communicate among themselves without assistance or human intervention. Large scale implementations has potential to create a huge aggregate traffic. Often brokers or intermediaries, are used to enable this machine-to-machine (M2M) communication using the Publish/Subscribe communication model that has several private libraries for use in Internet of Things. Some works developed by the community aim to treat performance in Publish/Subscribe brokers environment, however impose modifications and restrictions regarding brokers and architecture used. In this scenario, aiming to fulfill the need for cited scalability, we propose a elasticity model called PSElastic. The model provides an model with multilevel elasticity for Publish/Subscribe Brokers, making use of the elasticity promoted by cloud computing, not affecting system performance and without the need for investments or adjustments by customers and applications that make use of this model. PSElastic offers elasticity in the following manners: automatic, reactive and uses the multilevel elasticity, where multilevel refers to Broker level and Orchestrator model. In order to evaluate the model PSElastic, three different scenarios for execution of tests were defined: Scenario 1, without elasticity; Scenario 2, elasticity in the layer of Broker and Scenario 3, multilevel elasticity. Different limits of replica of virtual machines were used, as well as thresholds to evaluate Execution Time, number of Messages per Second handled and Efficiency in the use of computational resources. PSElastic showed excellent results by reducing the time needed to handle a data load by up to 81.2% and increase the throughput of the environment with Mosquitto Broker from 54.95 messages per second (Mps) to 235.29 Mps and from 38.02 Mps to 202.02 Mps in the environment with RabbitMQ Broker.
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Mahrenholz, Daniel. "Providing QoS for publish subscribe communication in dynamic ad-hoc networks." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980478588.
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Tong, Xiaoyu. "A Publish/Subscribe Platform Supporting Mobile Networks for Hybrid Sensor Networks." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-156438.
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Sparse sensor networks are cost-effective when deployed over large geographical areas. However, since sensor nodes cannot communicate with each other directly, how to connect those nodes to the Internet would be a problem. On the other hand, if traditional stationary sensors could be accessed from mobile phones, usability and functionality of participatory sensing applications could be enlarged. In this thesis, I design and implement a publish/subscribe platform which employing mobile phones connecting both stationary sensors and mobile sensors to the Internet. Through this platform, more sensor services could be utilized by participatory sensing applications and promising applications would be possible to emerge.
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Henjes, Robert [Verfasser]. "Performance evaluation of publish, subscribe middleware architectures / vorgelegt von Robert Henjes." Würzburg : Inst. für Informatik, Lehrstuhl für Verteilte Systeme, 2010. http://d-nb.info/1009637207/34.
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Schoettler, Michael R. "A Publish-Subscribe Framework for Embedded Systems| Simplifying the Development Process." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10604640.
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<p> The publish-subscribe pattern provides an array of benefits, applications, and performance enhancements, particularly for data sharing and development simplification within the FreeRTOS environment. The basic functionality of the publish-subscribe system is backed by a custom data structure which defines publishers and subscribers, and registers them with a so-called broker, which handles the notifications from publisher to subscriber whenever the publisher’s data is ready. It is shown that the cost of this system as compared to the usual direct inter-task notification provided by FreeRTOS does not introduce any significant performance degradation while also providing the programmer with a simplified communication method that both simplifies the way local inter-process communication occurs, and enables remote inter-process communication in a similarly straightforward way.</p><p>
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Daubert, Jörg [Verfasser], Max [Akademischer Betreuer] Mühlhäuser, and Thorsten [Akademischer Betreuer] Stufe. "Anonymous Publish-Subscribe Overlays / Jörg Daubert. Betreuer: Max Mühlhäuser ; Thorsten Stufe." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/111226938X/34.
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Andreasson, Samuel, and Jesper Palmér. "OPC UA Field eXchange Prototyping : Enabling decentralized communication using Publish/Subscribe." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-45029.
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Open Platform Communication Unified Architecture, or OPC UA, is a world-leading communication protocol specializing in unifying and automating production systems communication. In 2018 the OPC Foundation, an industrial consortium, started the OPC UA Field eXchange initiative to develop the current protocol to extend the reach of the communication down to field level devices like sensors and actuators. This paper explores whether OPC UA FX software can be implemented and integrated with HMS Networks’ product AnyBus CompactCom M40. The problem formulation stems from the future need for factory communication. For factories to compete, they need to adapt and keep up with the technological progression. OPC UA FX is based on decentralized communication where devices transmit data to each other by distributing the load over the entire system. The purpose of this report is to, based on the Open62541 implementation, develop software that extends OPC UA with PubSub functionality and methods that enable two or more instances to run as an FX application, meaning that the program publishes and subscribes data simultaneously. Once the software is developed, we integrate it on an AnyBus CompactCom 40 module. This will work as a communication prototype that proves that it is possible to extend OPC UA with FX into HMS Networks’ products. Open62541 is used to gather libraries and methods needed for OPC UA development. The software is developed using C in Visual Studios and integrated into the hardware using Eclipse. The result in the form of software was a connection-oriented data exchange, based on the OPC UA information model, where two or more instances can publish and subscribe to information simultaneously. HMS Networks can use the result on their way to implementing OPC UA FX in their products. In conclusion, the Open62541 implementation is beneficial when developing the OPC UA protocol. The software is complete, but it could not be fully integrated into the CompactCom module. The achieved application is still useful for the development of HMS Network’s products that might use the protocol.<br>Open Platform Communication Unified Architechure, eller OPC UA, är ett av de världsledande kommunikationsprotokoll som är specialiserat i att förena kommunikation i produktionssystem. 2018 startade OPC Foundation, ett industriellt konsortium, ett initiativ vid namn OPC UA Field eXchange med målet att utvekcla det nuvarande protokollet så att det kan användas till kommunikation på låg nivå, exempelvis mellan sensorer och ställdon. Denna rapport utforskar ifall det är möjligt att utveckla protokollet och integrera det i HMS Networks modul AnyBus CompactCom 40. Problemformluleringen baseras på framtida behov hos fabriker relaterat till automatisering. För att konkurrera framöver behöver fabriker anpassa sig till utvecklingen inom automatisering. OPC UA FX fokuserar på decentralierad kommunikation mellan enheter som fältanordning, maskin och moln samtidigt för att belastningen ska delas upp över hela systemet. Samtidigt som enheter i industiella nätverket fritt ska kunna överföra data mellan varandra oberoende vilken tillverkare som skapat enheten. Syftet med arbetet är att, baserat på Open62541, utveckla PubSub teknologi med metoder som möjlighetsgör att två eller fler instanser av en FX applikation ska kunna transportera data genom att prenumerera på och publicera data samtidigt. När mjukvaran fungerar är tanken att integrera mjukvaran på en AnyBus CompactCom 40 modul för att bevisa att implementationen är möjlig i ett praktiskt sammanhang. Open62541 används för att inkludera nödvändiga OPC UA bibliotek, funktionalitet och datatyper. Protokollet utvecklas i C i en VisualStudio miljö och integreras med hjälp av Eclipse. Resultatet i form av mjukvara var en kopplings intriktat data utbyte, baserad på OPC UA information modell, där en eller två instanser av ett program kan publicera och prenumerera på data samtidigt. HMS Networks kan använda resultatet i arbetet att implementera OPC UA FX i deras produkter. Sammanfattningsvis är Open62541 ett mycket användbart verktyg för utvekcling av OPC UA protokol. Dessvärre lyckades inte integrationen av mjukvaran i CompactCom modulen helt och hållet, men det som åstadkommits i arbetet kan i hög grad användas för fortsatt utveckling av OPC UA FX i HMS Networks produkter.
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Li, Wei. "A content-based publish/subscribe framework over structured peer-to-peer networks." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5645.
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The Publish/Subscribe model has become a prevalent paradigm for building
distributed notification services by decoupling the publishers and the subscribers from each other. Content-based publish/subscribe allows for highly
expressive descriptions of subscriptions and thus is more appropriate for content
dissemination when a finer level of granularity is necessary. However,
scalability has become an issue due to the expensive matching and delivering
inherent in content-based events. In this thesis we propose a novel content based
publish/subscribe framework built over a DHT-based P2P network in
order to provide scalable content delivery mechanisms. Based on efficient
subscription installation, event publishing and event delivery techniques, our
system can provide a scalable platform to support multiple different pub/
sub schemas. There are three key features in our design: (1) A logic space
mapping and a distributed 2d-tree that maintains this space over DHT;
(2) Novel random probing searching schemes allowing for subscription installation
and event publication; (3) An efficient application layer multicast
algorithm for message delivery with low bandwidth consumption.
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Pesonen, Lauri I. W. "A capability-based access control architecture for multi-domain publish/subscribe systems." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612114.
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Mormone, Giovanni. "Analisi e sviluppo di un sistema per l’ottimizzazione di reti publish/subscribe." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24206/.
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Lo sviluppo di tecnologie che sfruttano il paradigma Internet of Things(IoT)ha portato all’utilizzo sempre più diffuso di reti formate da diversi devices
disseminati nel territorio, con il paradigma Publish/Subscribe come uno deiparadigmi di comunicazione più utilizzati per applicazioni di questo tipo.
L’adozione di questi sistemi porta però anche al sorgere di vari problemi elimitazioni, ad esempio dovuti alla limitata capacità delle batterie dei devicesutilizzati, alla limitata capacità di banda della connessione all’interno della
rete o alle limitate capacità di memoria e di numero di connessioni che è possibile gestire all’interno della rete. Questo lavoro si concentra sullo sviluppo di un sistema in grado di trovare la configurazione di rete più efficiente
per permettere ad un’applicazione IoT che sfrutta il paradigma Publish/Subscribe di massimizzare il numero di connessioni e ridurre lo spreco di risorse
all’interno di essa, a partire dalla definizione dei devices e delle connessionitra gli stessi presenti nel sistema. Per raggiungere lo scopo viene sfruttata la programmazione lineare intera, proponendo delle formulazioni matematiche
in grado di risolvere ed ottimizzare il problema della configurazione di rete in contesti dove le risorse a disposizione dei devices sono limitate.
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Oudishu, Ramcin, and Pethrus Gärdborn. "A CoAP Publish-Subscribe Broker for More Resource-Efficient Wireless Sensor Networks." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232076.
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With the rapid development of the Internet of Things, Wireless Sensor Networks (WSNs) are deployed increasingly all over the world, providing data that can help increase sustainable development. Currently in Uppsala, Sweden, the GreenIoT project monitors air pollution by using WSNs. The resource constrained nature of WSNs demand that special care is taken in the design of communication models and communication protocols. The publish-subscribe (pub/sub) model suits WSNs very well since it puts an intermediary the broker server between sensor nodes and clients, thus alleviating the workload of the sensor nodes. The IETF (Internet Engineering Task Force) is currently in the process of standardizing a pub/sub extension to the Constrained Application Protocol (CoAP). Since the extension is such a recent addition to CoAP and not yet standardized, there are very few actual implementations of it and little is known of how it would work in practice. The GreenIoT project is considering replacement of their current pub/sub broker with the CoAP pub/sub broker since its underlying implementation is likely to be more energy efficient and the standardizing organization behind CoAP is the well-esteemed IETF. On a general level, this report offers an investigation of the problems and challenges faced when implementing the CoAP pub/sub extension with respect to design choices, implementation and protocol ambiguities. More specifically, a CoAP pub/sub broker is implemented for the GreenIoT project. By means of carefully analyzing the CoAP protocol and CoAP pub/sub draft as well as other necessary protocols, then proceeding to make decisions of what programming language to use as well as what existing CoAP library to use, a broker server was implemented and tested iteratively as the work proceeded. The implementation gave rise to several questions regarding the pub/sub draft which are also discussed in the report.<br>Den hastiga utvecklingen av Sakernas Internet över hela världen har medfört ett ökat användande av trådlösa sensornätverk vars datainsamling kan bidra till en mer hållbar utveckling. För närvarande använder sig GreenIoT-projektet i Uppsala av trådlösa sensornätverk för att övervaka halterna av luftföroreningar. Resursbegränsningarna för dylika nätverk medför att särskild hänsyn måste tas vid design av såväl kommunikationsmodeller som kommunikationsprotokoll. Modellen Publicera-Prenumerera (pub/pre) passar ypperligt för trådlösa sensornätverk då en mellanhand placeras mellan klient och server en s.k. broker vilket får den positiva effekten att att sensornoderna avlastas. För närvarande är IETF (Internet Engineering Task Force) i färd med att standardisera en pub/pre-utvidgning av det redan standardiserade CoAP (Constrained Application Protocol). Eftersom att utvidgningen är så pass ny finns ytterst få implementationer av den och man vet därmed väldigt lite om hur den faktiskt fungerar i praktiken. GreenIoT-projektet överväger att ersätta sin nuvarande pub/pre-broker med en CoAP pub/pre-broker eftersom att energianvändningen kan antas bli lägre samt att standardiseringsorganisationen bakom CoAP är det välrenommerade IETF. Sett ur ett större perspektiv erbjuder denna rapport en undersökning av de problem och utmaningar man ställs inför vid implementation av CoAP pub/pre-utvidgningen med avseende på designval, implementationsval, och protokolltvetydigheter. Mer konkret implementeras en CoAP pub/pre-broker åt GreenIoT-projektet. Genom att först noggrant analysera CoAP-protokollet, CoAP pub/pre-utkastet, liksom andra nödvändiga protokoll, för att därefter bestämma vilket programmeringsspråk och vilket existerande CoAP-bibliotek som skulle användas, implementerades en broker server som testades iterativt under processens gång. Ett flertal frågor som uppstod rörande pub/pre-utkastet presenteras och diskuteras i rapporten.
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Mekhitarian, Araxi. "Reducing Software Complexity in a Distributed Publish-Subscribe system using Multicast communication." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232120.
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Systems of distributed character are increasing in size and becoming more complex. Managing and adapting to constant changes of requirements is a challenge during the entire system development life cycle. While new functionalities are implemented, the software may change in design and may lead to poor software quality and increased system complexity. This thesis focuses on tackling the complexity issue in a distributed Electronic Warfare system used in military aircraft. The system consists of a server and several clients which acts as publishers or subscribers for different events sent in the system. The communication is based on unicast and uses a publish/subscribe pattern for the client nodes to register as publishers or subscribers to the server. The system is created to handle message passing in high rate and is sensitive for message delays. Due to this, the system is dependent on a reliable network structure with a continuous necessity for development. An implementation of a multicast prototype will be replacing the topic-specific unicast communication and the publish/subscribe registration process to the server. The system will be evaluated by a comparison of the old communication version with the new multicast implementation using software metrics. The result is to evaluate if the behavior and functionality of the distributed Electronic Warfare system change.<br>System av distribuerad karaktär ökar i storlek och blir alltmer komplex. Att hantera och anpassa sig till ständiga kravändringar är emellertid en utmaning under hela systemets utvecklingsprocess. Medan nya funktioner implementeras kan mjukvaran ändras i design vilket kan leda till dålig programkvalitet och ökad systemkomplexitet. Denna rapport fokuserar på att hantera komplexiteten i ett distribuerat telekrigföringssystem som används i militära flygplan. Systemet består av en server och flera klienter som publicerar och prenumererar för olika typer av meddelanden som skickas i systemet. Kommunikationen baseras på enkelsändning och använder ett publish/subscribe meddelandemönster där klienterna registrerar sig som publicerare eller prenumeranter till servern. Systemet är skapat för att kunna hantera höga meddelandehastigheter och har låg tolerans för meddelandeförseningar. På grund av detta är tillförlitlighet i nätverksstrukturen ett essentiellt kvalitetsattribut då nätverket är i behov av en ständig utveckling. En prototyp av multisändning kommer att implementeras och ersätta kommunikationen baserad på enkelsändning och publish/subscribe registreringsprocessen till servern. Systemet kommer att utvärderas genom en jämförelse av den gamla kommunikationsversionen av systemet med den nya multicast-implementeringen med hjälp av mjukvarukomplexitetsmätningar. Resultatet är att utvärdera om beteendet och funktionaliteten hos det distribuerade telekrigföringssystemet ändras.
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Huang, He. "A Publish/Subscribe Data Gathering Framework Integrating Wireless Sensor Networks and Mobile Phones." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-136400.
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In this report, we propose a data gathering framework integrating wireless sensors with mobile phones based on the observation that individual mobile devices can serve as supplement to the static deployed wireless sensor networks. The framework employs an intermediate broker network built upon DHT overlay in its basic infrastructure to dispatch data by means of publish/subscribe paradigm. A location based subscription installation is introduced, through which end users can subscribe to their interested events within a specified target location area. Event data notifications are multicast efficiently by the broker network back to the corresponding subscriber clients when they are matched successfully against any subscriptions. In order to support client mobility, we also propose a protocol which implements a client location registration and lookup process as well as a relocation handover process. The protocol leverages the DHT storage of broker nodes to trace client location. It is able to buffer the event data when clients are absent to the framework and replay them efficiently to the new location in case of client relocation.
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Shen, Zhenhui. "Techniques for building a scalable and reliable distributed content-based publish/subscribe system." [Ames, Iowa : Iowa State University], 2007.
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Tariq, Muhammad Adnan [Verfasser], and Kurt [Akademischer Betreuer] Rothermel. "Non-functional requirements in publish, subscribe systems / Muhammad Adnan Tariq. Betreuer: Kurt Rothermel." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2013. http://d-nb.info/1037955978/34.
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Sivaharan, Thirunavukkarasu. "Towards a generic and adaptable publish/subscribe middleware to facilitate pervasive computing applications." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578249.
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The publish/subscribe paradigm is well known for its loosely-coupled and asynchronous communication model. The paradigm, it is argued, is also well suited for pervasive computing applications given the above characteristics. There has been a great deal of research work, particularly over the last decade, on the publish/subscribe paradigm producing many novel publish/subscribe schemes and other results in specific deployment scenarios. However the major shortcoming of this body of work is that present day platforms have not yet enjoyed wide-spread deployment in real-world applications, even though large numbers of applications are naturally event-driven. As this thesis will argue one root technical cause for the above mentioned predicament is that state-of-the art publish/subscribe middleware technologies are to a large extent intrinsically tied to a particular network type, have a one-size 'fixed' monolithic infrastructure and generally offer a fixed interaction type. Hence, they are not well placed and fundamentally overstretched to cope with ever growing heterogeneity and application diversity. To address this limitation the thesis proposes an approach that is centred on a generic and adaptable framework, separation of concerns and component frameworks. The resultant middleware (named GREEN) can: 1) gracefully deliver a wide range of custom infrastructure(s) that scale-up and down in terms of functionality, complexity and size, 2) facilitate the trade-off of a large number of competing design parameters, and 3) gracefully overcome heterogeneity. These findings are validated through a range of experiments covering heterogeneous network types (e.g. MANET, WSN, NES, WAN), device types (e.g. tiny motes, mobile devices, embedded devices and PCs) and application profiles. Significantly results show the framework is indeed feasible, does not result in one-size bloated and complex infrastructure, and the overheads introduced by the adaptive operations are found to be acceptably low in general.
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Daubert, Jörg. "Anonymous Publish-Subscribe Overlays." Phd thesis, 2016. https://tuprints.ulb.tu-darmstadt.de/5473/9/2016-05-03%20ClassicThesis_2.pdf.
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Freedom of speech is a core value of our society. While it can be exercised anonymously towards undesired observers in the physical world, the Internet is based on unique and nonanonymous identifiers (IDs) for every participant. Anonymity, however, is a crucial requirement to exercise freedom of speech using the Internet without having to face political persecution. To achieve anonymity, messages must be unlinkable to senders an receivers. That means that messages cannot be linked to IDs and other identifying information of senders and receivers. Anonymization services, such as Tor, re-establish anonymity within the Internet such that, for example, web content can be consumed anonymously.
Nevertheless, this type of solution embodies two challenges: First, with the appearance of social media, the Internet usage behavior changed drastically from a one producer with many consumers to a many producers with many consumers of content paradigm. Second, a social media website that is used by many producers and many consumers constitutes a single point of failure (SPoF) regarding both availability and anonymity. Such a website may collect producer and consumer profiles, ultimately breaking anonymity.
Publish/subscribe (pub/sub) is a message dissemination paradigm well suited to address the first challenge, the many-to-many exchange of content. peer-to-peer (P2P) Pub/Sub eliminates the need for an SPoF and, thus, partially addresses the second challenge as well. However, research addressing anonymity as a security requirement for Pub/Sub has merely scratched the surface.
This thesis improves the state-of-the-art in anonymous Pub/Sub in several areas. In particular, the thesis addresses the following aspects of constructing anonymous Pub/Sub systems: (i.) Building blocks that reduce the complexity of constructing anonymous Pub/Sub systems are proposed; (ii.) methods for anonymously establishing Pub/Sub overlay networks are presented; (iii.) a method for inter-overlay optimization to distribute load is introduced; (iv.) methods for optimizing overlays regarding anonymity are proposed, and (v.) anonymity attacks and countermeasures are presented.
Contributions.
This thesis contributes to the following research categories:
Anonymous overlay establishment: An anonymous Pub/Sub system is presented along six self-containing building blocks with the goal of establishing overlay networks that transport notifications from publishers to subscribers. Each building block is discussed in detail with a focus on leveraging related work to realize the building block. For attribute localization, the building block most relevant for establishing overlays, this thesis proposes multiple contributions: the usage of hash chains as a privacy-preserving transaction pseudonym and distance metric; the adaptation of flooding as well as forest fires; and random walks to distribute attribute knowledge.
Anonymous overlay optimization: The thesis proposes two optimizations for anonymity and one optimization for balancing the load. The first anonymity optimization, probabilistic forwarding (PF), applies the concept of mimic traffic to the domain of Pub/Sub. The second anonymity optimization, the shell game (SG), shuffles the overlay. Both optimizations prevent an exposure of information to attackers that can gain knowledge about the overlay topology. The load-balancing optimization uses a ring communication and Bloom filters to distribute load among nodes.
Anonymity attacks and countermeasures: Several well-known anonymity attacks are adapted to the domain of anonymous Pub/Sub and evaluated in detail. Novel attacks, such as the request/response-attack and the corner attack, are proposed as well and complemented with countermeasures.
Evaluation.
The proposed mechanisms and attacks are evaluated using a qualitative approach, quantitatively with an extensive simulation, and empirically with a proof of concept (POC) application. The qualitative approach indicates that the presented mechanisms are well-suited to protect anonymity against a malicious insider threat.
The quantitative evaluation is performed with the event-based simulation framework OMNeT++. The results show that the presented anonymous Pub/Sub system can protect anonymity, even in case malicious insiders are combined with a global observer of a very strong anonymity threat. The results also reveal in which situations PF or the SG provides the better anonymity protection. Furthermore, the results indicate which capabilities are favorable for an anonymity attacker.
An anonymous micro-blogging application for Twitter shows that the presented system can be implemented for a real-world use case: With the application, users exchange tweets via hashtag-overlays, and cryptographic keys via quick response (QR)-codes and near field communication (NFC).
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Agarwal, N. "Publish - subscribe based communication model." Thesis, 2014. http://ethesis.nitrkl.ac.in/6074/1/E-198.pdf.
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Publish-Subscribe is an expression used to describe an application model in which supplier of some data (Publisher) is decoupled from the consumers of that data (Subscriber). Publish-Subscribe paradigm is an asynchronous messaging paradigm. Publishers are unaware of receivers i.e. they do not send messages to specific receivers. Instead, the messages published are divided into classes, oblivious of the subscribers. Subscribers express interest in one or more classes, and only receive messages that are of interest, without any awareness of the publishers. The thesis studies publish-subscribe model and the paradigm’s advantages in distributed computing. The thesis also proposes a scheme to respond to user’s interests derived from both published content and subscribed content, if any. This model has applications in Blogging Systems, Advertisements and Recommendation Systems.
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Yoon, Young. "Adaptation Techniques for Publish/Subscribe Overlays." Thesis, 2013. http://hdl.handle.net/1807/36075.
Full textAbstract:
Publish/Subscribe (in short pub/sub) allows clients that share common interest communicate in an asynchronous and loosely-coupled fashion. This paradigm is adopted by many distributed event-driven applications such as social networking services, distributed business processes and cyber-physical systems. These applications cannot afford to have the underlying pub/sub substrate perform unreliably, permanently fail or behave arbitrarily as it will cause significant disturbance to stably serving many end-users. Therefore, a research effort on making pub/sub systems resilient against various failures to sustain high quality of service to the clients is imperative. In this thesis, we focus on the overlay of pub/sub brokers that are widely adopted as a popular architecture for large-scale pub/sub systems. Broker overlays can suffer from various issues such as degradation of topology quality, brokers causing transient or permanent benign failures and Byzantine brokers behaving arbitrarily. We aim to make novel research contributions by exploring fundamental techniques that can help the broker overlays maintain functional and non-functional requirements even under the presence of the aforementioned failures and necessary administrative updates. We first build a set of overlay adaptation primitives that re-configure topologies such as shifting links and replicating brokers. These primitives are designed to involve a small local group of brokers in the pub/sub overlays so that the disruption during the execution of large-scale and dynamic changes can be controlled in a fined-grained manner. For the problem of degrading topology quality, automated planning systems are developed to find a sequence of adaptations that would cause minimal disruption to running services. Also, our primitives can be executed on demand to quickly fail-over a crashed broker or off-load congested brokers. In addition, these on-demand primitives can be used to form a group of dynamically replicated brokers that enforce a novel safety measure to prevent Byzantine brokers from sabotaging the pub/sub overlays. Our contributions are evaluated with systematic consideration of various trade-offs between functional and non-functional properties.