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Dissertations / Theses on the topic 'Dissemination'
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Fleetwood, Brian. "Artificial Dissemination." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3433.
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This writing is an experiment in combining the two most important frameworks through which I understand the world, the storytelling traditions of my people, the Mvskoke(Creek), and the rational tradition that began with European Enlightenment era thinking. By weaving allegorical narrative (much of it personal) into theoretical speculation, I draw connections between recollection, truth, and the act of making. This examination of the gaps and connections between seemingly disparate worldviews, runs in parallel to the purpose of my work, wherein I construct fictive symbiotic and parasitic relationships between jewelry and wearer. This work takes advantage of the wearer as environment, resource, and propagator. By abstracting from real-world biological structures, this work conflates genetic and memetic dissemination. I am creating systems and models of systems using individual jewelry pieces for specific wearers that reflect the structure of arrangements that are repeated throughout nature. Ultimately I am raising questions about the hard lines that we draw between things in nature—including ourselves—and our place in biological, cultural, and personal systems.
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Wang, Bohe. "Information dissemination by compounding." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3532.
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Thesis (Ph. D.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains iv, 146 p. : ill. (some col.) + computer files. Includes supplementary version computer files in java applets, txt, and MS Word. Includes abstract. Includes bibliographical references (p. 90-91).
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Polaha, J. P., and Robert P. Pack. "Dissemination and Implementation Science." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/1351.
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Trullols, Cruces Oscar. "Information dissemination in mobile networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/276176.
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This thesis proposes some solutions to relieve, using Wi-Fi wireless networks, the data consumption of cellular networks using cooperation between nodes, studies how to make a good deployment of access points to optimize the dissemination of contents, analyzes some mechanisms to reduce the nodes' power consumption during data dissemination in opportunistic networks, as well as explores some of the risks that arise in these networks.
Among the applications that are being discussed for data off-loading from cellular networks, we can find Information Dissemination in Mobile Networks.
In particular, for this thesis, the Mobile Networks will consist of Vehicular Ad-hoc Networks and Pedestrian Ad-Hoc Networks. In both scenarios we will find applications with the purpose of vehicle-to-vehicle or pedestrian-to-pedestrian Information
dissemination, as well as vehicle-to-infrastructure or pedestrian-to-infrastructure Information dissemination. We will see how both
scenarios (vehicular and pedestrian) share many characteristics, while on the other hand some differences make them unique, and therefore requiring of specific solutions. For example, large car batteries relegate power saving techniques to a second place, while power-saving techniques and its effects to network performance is a really relevant issue in Pedestrian networks.
While Cellular Networks offer geographically full-coverage, in opportunistic Wi-Fi wireless solutions the short-range non-fullcoverage paradigm as well as the high mobility of the nodes requires different network abstractions like opportunistic networking,
Disruptive/Delay Tolerant Networks (DTN) and Network Coding to analyze them.
And as a particular application of Dissemination in Mobile Networks, we will study the malware spread in Mobile Networks.
Even though it relies on similar spreading mechanisms, we will see how it entails a different perspective on Dissemination.
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Egeland, Silje Bentzen. "Privacy handling in context dissemination." Thesis, Norwegian University of Science and Technology, Department of Telematics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10069.
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Pervasive environments are characterized by ubiquitous, mobile and embedded computing devices and wireless networking. The vision is an environment where the technology resides in the background ready to be used when it is needed. An essential part of such environments is context aware applications and context information. A context aware system exploits context information to provide relevant services or information to an entity, where relevancy depends on the entitys task. As a user, the employment of such systems involves revealing a lot of personal data. Context information can divulge a lot of sensitive information which represents a threat to a persons privacy. This master thesis looks into privacy handling in pervasive computing environments. The object is to propose a solution on how a user can control the extent of access to his or her context information. In order to identify the most important privacy concerns in the implementation of a context management system, privacy principles are looked into and privacy challenges in consequence of pervasive computing are evaluated. The different strategies for handling privacy are pointed out, such as legislation, self-regulation and technology. Among these, technology is further looked into, first through an evaluation of existing solutions and research projects, then through design an implementation of a possible solution. The principles which are identified to be most important to handle are a users awareness of data collection and the possibility to restrict this collection. In addition it is pointed out the importance of making the system convenient to use. The heterogeneity of different users privacy preferences implies that some kind of personalization of the system should be present. A design and an implementation are presented which propose a solution where a user can constrain the access to his or her personal data, based on other users identities, his or her present situation and the type of context information the other users want to receive. The system also includes functionality to abstract details away from the context information which is disseminated to other system users/entities.
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Hobson, Adrian Surveying & Spatial Information Systems Faculty of Engineering UNSW. "Digital plan lodgement and dissemination." Awarded by:University of New South Wales. School of Surveying and Spatial Information Systems, 2004. http://handle.unsw.edu.au/1959.4/24231.
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In Australia, in recent years there has been increasing demand for more streamlined lodgement of cadastral plans and for their later dissemination. There are a number of approaches to meeting this demand, one of which is developed in detail in this dissertation. The current status of digital lodgement and Digital Cadastral Databases (DCDB) throughout Australia and New Zealand is reviewed. Each of the states and territories in Australia and also New Zealand are examined, looking at the process involved in the lodgement of survey plans and the state of the DCDB in each jurisdiction. From this examination the key issues in digital lodgement and dissemination are extracted and a needs analysis for an Australia-wide generic system is carried out. This needs analysis is directed at technological change allied with sound cadastral principles. Extensible Markup Language (XML) is considered for the storage and transport of all the required data and to facilitate the dissemination of information over the Internet. The benefits of using XML are comprehensive, leading to its selection and the use of related technologies LandXML, Extensible Structured Query Language (XSQL) and Extensible Stylesheet Language (XSL). Vector graphics are introduced as the means to display plans and maps on the Internet. A number of vector standards and Web mapping solutions are compared to determine the most suitable for this project. A new standard developed by the World Wide Web Consortium (W3C), Scalable Vector Graphics (SVG), is chosen. A prototype Web interface and the underlying database and Web server were developed using Oracle as the database and Apache as the Web server. Each aspect of the development is described, starting with the installation and configuration of the database, the Web server and the XSQL servlet. Testing was undertaken using LandXML cadastral data and displaying plans using SVG. Both Internet Explorer and Mozilla were trialled as the Web browser, with Mozilla being chosen because of incompatibilities between Internet Explorer, LandXML and SVG. An operational pilot was created. At this stage it requires manual intervention to centre and maximise a plan in the display area. The result indicates that an automated system is feasible and this dissertation provides a basis for further development by Australian land administration organisations.
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Thornton, Karin E. Marenic Timothy. "Intelligence dissemination to the warfighter." Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Dec%5FThornton.pdf.
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Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2007.Thesis Advisor(s): Denning, Dorothy. "December 2007." Description based on title screen as viewed on January 23, 2008. Includes bibliographical references (p. 49-52). Also available in print.
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Han, Fu Ching Eliza, and 韓馥璟. "Dissemination of language education review." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B50175208.
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教育改革时不时会顺应社会变迁与经济转型而进行，新加坡也不例外。新加坡教育部为了顺应新一代学生与社会需求的转变，于2004 年进行了华文教育改革。改革的传播与推广直接地影响改革成效，是实施课程改革的过程中举足轻重的一环。本研究便希望能够通过新加坡国际学校（香港）的个案研究，探讨并评估新加坡教育部推广与传播华文课程改革的策略，以及新加坡国际学校（香港）实施教育改革与新课程的成效。
本研究以课程推广与传播及教育改革的基本理论为基础，着重研究新加坡教育部推广新课程到新加坡国际学校（香港）的过程，以及新加坡国际学校（香港）内部如何推广新课程，从中总结归纳影响今次推广与传播课程改革策略的不同因素。研究中采用质性与量性的研究法，如访谈、问卷调查、文件分析、课堂观察等，从多方面建构个案。
Education reviews often take place as a result of societal changes and economic developments, and education reviews in Singapore is no exception. The background of this study stems from the latest Singaporean Chinese Language Curriculum Review in 2004. The dissemination of education reviews has a direct impact on the effective implementation of the reviewed curriculum; hence it is important to learn about how dissemination takes place in a review cycle. This study aims to discuss and evaluate the strategies of dissemination and diffusion used by the Singapore Ministry of Education in disseminating educational to the Singapore International School (Hong Kong).(HKSIS)
This study is based on the theories of curriculum dissemination and diffusion , together with theories of educational change, and is focused on the dissemination process of the new Primary Chinese Language Curriculum to HKSIS , and the diffusion process within HKSIS, so as to discover the different factors affecting the effectiveness of dissemination and diffusion for HKSIS. This study uses both quantitative and qualitative research method to build a multi-faceted case study, such as interviews, text analysis, classroom observation and questionnaire surveys.published_or_final_version
Education
Master
Master of Education
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Marenic, Timothy. "Intelligence dissemination to the warfighter." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3101.
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This thesis explores the intelligence cycle with emphasis on the dissemination of data from the intelligence community to forward deployed operators, also known as the warfighters. The study focuses on the bottlenecks and other flaws within the IC that may cause delays in getting intelligence reports and products in support of national security to customers around the globe. The IC has undergone several changes since the 2001 terror attacks on the United States, thanks to the 9/11 Commission and the 2004 Intelligence Reform Act. These changes have streamlined bureaucratic processes and budget allocations, but there is still a need to acquire systems and software that maximize data transfer and security. Several commercial companies have designed collaborative tools that claim to support improved data handling. Intelligence Support Server Environment (ISSE) guard is the primary tool the US Air Force employs for exchanging data between the IC and the operators. This thesis will review the advertised upgrade to ISSE along with other tools and provide an unbiased perspective on how these tools might facilitate data dissemination to the warfighters.
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Joubert, Melanie. "Dissemination research : teachers as facilitators." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/25514.
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The purpose of this study was to explore and describe the experiences of teachers fulfilling the role of facilitators of the STAR intervention with fellow teachers at two neighbouring schools. The study constituted part of a broader research project that commenced in 2003, at a primary school in the Eastern Cape. At the time of the current study, seven of the ten teachers who participated in the initial study were replicating the initial study’s strategy in two neighbouring schools in an attempt to assist the teachers in providing psychosocial support. In an attempt to explore the experiences of the teacher-facilitators I observed a STAR intervention session (November, 2008), that involved four participants facilitating a STAR intervention session at the neighbouring school. Following my observation of the intervention session, I co-facilitated a focus group, exploring the teacher-facilitators’ experiences in fulfilling the role of peer-facilitators. Two days after the first focus group, I co-facilitated a follow-up focus group for the purpose of member-checking. In addition, I relied on field notes and visual data as data sources. Based on the data analysis that followed, three main themes emerged. Firstly, the teachers seemed to ascribe meaning on a personal level in terms of their experiences as facilitators of STAR. They experienced joy in sharing knowledge and enabling others, feelings of self-worth and self-confidence, personal development and growth, as well as confirmed commitment and motivation. Secondly, they experienced a shared voice in the community, in response to the peer-facilitation of STAR, referring to appreciation and trust that inspired enthusiasm for participation in various school-community systems and a sense of community as outcome of facilitation. Thirdly, participants identified aspects related to being a peer-facilitator, in terms of overcoming feelings of uncertainty and concern, working as a team, relying on creative problem solving when dealing with potential challenges, and extending the scope of facilitation. Based on the findings of the study I concluded that the participating teachers experienced the facilitation of STAR in a positive manner on both a personal and professional level. As a result of their positive experiences, they seemed to become even more committed and motivated than initially, to support their community through the facilitation of STAR. Their positive experiences seemingly influenced their perceived development in terms of self-efficacy beliefs and actualisation, which in turn enhanced their personal and professional growth, thereby forming a cycle of improved positive experiences on various levels.Dissertation (MEd)--University of Pretoria, 2010.
Educational Psychology
unrestricted
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Panossian, Garo. "MULTI-LEVEL SECURE DATA DISSEMINATION." CSUSB ScholarWorks, 2019. https://scholarworks.lib.csusb.edu/etd/946.
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Multi-level security is prevalent within the military; however, the private sector has not yet invested in the approach. As big data, Internet of things, and artificial intelligence drive businesses to collaborate (share data, algorithms, and tools) the need to secure such resources while simultaneously sharing them will push towards an alternative approach-–namely Multi-level security. The military labels data according to the sensitivity it carries as related to national security. Furthermore, the military restricts access by both the overall trust in the individual and by their need-to-know. To put it another way, data has a certain level of sensitivity and only those individuals that can be trusted with the data and have a need-to-know shall have access to such data. Military organizations not only limit access to digital data but also to sensitive discussions, often having sensitive talks within a Sensitive Compartmented Information Facility referred to as a SCIF. Irrespective of the media, all data must be secured and disseminated in order to produce value. Inaccessible data has no real value, as data must be accessible in order to be actionable and produce value. Along the same lines, data often requires aggregation to become actionable.
Creating a security domain with multiple levels of trust and need-to-know ensures that data can both be accessed and aggregated. Multi-level secure domains exist in military organizations today, however, the challenge arises when two domains want to share data—hence the need for multi-level secure data dissemination. One way to accomplish this objective is for Domain X to contact Domain Y and together identify how their two security domains can map to one another. After determining the mapping Domain X can send Domain Y data, however, what if Domain Z wants access to the same data? Should Domain Z request the data from Domain Y? Would Domain Y violate the trust of Domain X, if Domain Y disseminates the data? Perhaps, Domain Z is only cleared to a portion of the data. These are the issues related to the dissemination of MLS data within a multi-domain environment.
The objective of this project is to propose a solution that would allow domains to securely disseminate data without the need to repackage the data for each domain. The solution outlined in this project, leverages Simple Public Key certificates, Active Bundle, and a directory server. When combined, the three technologies allow domains: to convey both trust and authorization policies, learn about trust and authorization policies of external domains, and provide a mechanism to securely disseminate data.
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Gel, Moreno Bernat. "Dissemination and visualisation of biological data." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/283143.
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With the recent advent of various waves of technological advances, the amount of biological data being generated has exploded. As a consequence of this data deluge, new challenges have emerged in the field of biological data management. In order to maximize the knowledge extracted from the huge amount of biological data produced it is of great importance for the research community that data dissemination and visualisation challenges are tackled. Opening and sharing our data and working collaboratively will benefit the scientific community as a whole and to move towards that end, new developements, tools and techniques are needed.
Nowadays, many small research groups are capable of producing important and interesting datasets. The release of those datasets can greatly increase their scientific value. In addition, the development of new data analysis algorithms greatly benefits from the availability of a big corpus of annotated datasets for training and testing purposes, giving new and better algorithms to biomedical sciences in return. None of these would be feasible without large amounts of biological data made freely and publicly available.
Dissemination
The Distributed Annotation System (DAS) is a protocol designed to publish and integrate annotations on biological entities in a distributed way. DAS is structured as a client-server system where the client retrieves data from one or more servers and to further process and visualise. Nowadays, setting up a DAS server imposes some requirements not met by many research groups. With the aim of removing the hassle of setting up a DAS server, a new software platform has been developed: easyDAS. easyDAS is a hosted platform to automatically create DAS servers. Using a simple web interface the user can upload a data file, describe its contents and a new DAS server will be automatically created and data will be publicly available to DAS clients.
Visualisation
One of the most broadly used visualization paradigms for genomic data are genomic browsers. A genomic browser is capable of displaying different sets of features positioned relative to a sequence. It is possible to explore the sequence and the features by moving around and zooming in and out. When this project was started, in 2007, all major genome browsers offered quite an static experience. It was possible to browse and explore data, but is was done through a set of buttons to the genome a certain amount of bases to left or right or zooming in and out. From an architectural point of view, all web-based genome browsers were very similar: they all had a relatively thin clien-side part in charge of showing images and big backend servers taking care of everything else. Every change in the display parameters made by the user triggered a request to the server, impacting the perceived responsiveness.
We created a new prototype genome browser called GenExp, an interactive web-based browser with canvas based client side data rendering. It offers fluid direct interaction with the genome representation and it's possible to use the mouse drag it and use the mouse wheel to change the zoom level. GenExp offers also some quite unique features, such as its multi-window capabilities that allow a user to create an arbitrary number of independent or linked genome windows and its ability to save and share browsing sessions. GenExp is a DAS client and all data is retrieved from DAS sources. It is possible to add any available DAS data source including all data in Ensembl, UCSC and even the custom ones created with easyDAS.
In addition, we developed a javascript DAS client library, jsDAS. jsDAS is a complete DAS client library that will take care of everything DAS related in a javascript application. jsDAS is javascript library agnostic and can be used to add DAS capabilities to any web application.
All software developed in this thesis is freely available under an open source license.Les recents millores tecnològiques han portat a una explosió en la quantitat de dades biològiques que es generen i a l'aparició de nous reptes en el camp de la gestió de les dades biològiques. Per a maximitzar el coneixement que podem extreure d'aquestes ingents quantitats de dades cal que solucionem el problemes associats al seu anàlisis, i en particular a la seva disseminació i visualització. La compartició d'aquestes dades de manera lliure i gratuïta pot beneficiar en gran mesura a la comunitat científica i a la societat en general, però per a fer-ho calen noves eines i tècniques. Actualment, molts grups són capaços de generar grans conjunts de dades i la seva publicació en pot incrementar molt el valor científic. A més, la disponibilitat de grans conjunts de dades és necessària per al desenvolupament de nous algorismes d'anàlisis. És important, doncs, que les dades biològiques que es generen siguin accessibles de manera senzilla, estandaritzada i lliure. Disseminació El Sistema d'Anotació Distribuïda (DAS) és un protocol dissenyat per a la publicació i integració d'anotacions sobre entitats biològiques de manera distribuïda. DAS segueix una esquema de client-servidor, on el client obté dades d'un o més servidors per a combinar-les, processar-les o visualitzar-les. Avui dia, però, crear un servidor DAS necessita uns coneixements i infraestructures que van més enllà dels recursos de molts grups de recerca. Per això, hem creat easyDAS, una plataforma per a la creació automàtica de servidors DAS. Amb easyDAS un usuari pot crear un servidor DAS a través d'una senzilla interfície web i amb només alguns clics. Visualització Els navegadors genomics són un dels paradigmes de de visualització de dades genòmiques més usats i permet veure conjunts de dades posicionades al llarg d'una seqüència. Movent-se al llarg d'aquesta seqüència és possibles explorar aquestes dades. Quan aquest projecte va començar, l'any 2007, tots els grans navegadors genomics oferien una interactivitat limitada basada en l'ús de botons. Des d'un punt de vista d'arquitectura tots els navegadors basats en web eren molt semblants: un client senzill encarregat d'ensenyar les imatges i un servidor complex encarregat d'obtenir les dades, processar-les i generar les imatges. Així, cada canvi en els paràmetres de visualització requeria una nova petició al servidor, impactant molt negativament en la velocitat de resposta percebuda. Vam crear un prototip de navegador genòmic anomenat GenExp. És un navegador interactiu basat en web que fa servir canvas per a dibuixar en client i que ofereix la possibilitatd e manipulació directa de la respresentació del genoma. GenExp té a més algunes característiques úniques com la possibilitat de crear multiples finestres de visualització o la possibilitat de guardar i compartir sessions de navegació. A més, com que és un client DAS pot integrar les dades de qualsevol servidor DAS com els d'Ensembl, UCSC o fins i tot aquells creats amb easyDAS. A més, hem desenvolupat jsDAS, la primera llibreria de client DAS completa escrita en javascript. jsDAS es pot integrar en qualsevol aplicació DAS per a dotar-la de la possibilitat d'accedir a dades de servidors DAS. Tot el programari desenvolupat en el marc d'aquesta tesis està lliurement disponible i sota una llicència de codi lliure.
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Högger, Patrik Jules. "Dissemination of the cryphonectria hypovirus CHV1 /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13276.
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Hasler, Andreas. "iWARP-based high-definition media dissemination." Zurich : ETH, Swiss Federal Institute of Technology Zurich, Department of Computer Science, Systems Group : IBM Zurich Reserach Laboratory, Systems Department, 2009. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=448.
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Wan, Yung-Chun Justin. "Algorithms for data dissemination and collection." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2401.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Computer Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Stretch, Jonathan Raymond Granger. "The local dissemination of cutaneous melanoma." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291594.
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Gomez, Angel. "The mayor and early Lollard dissemination." Honors in the Major Thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/564.
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During the fourteenth century in England there began a movement referred to as Lollardy. Throughout history, Lollardy has been viewed as a precursor to the Protestant Reformation. There has been a long ongoing debate among scholars trying to identify the extent of Lollard beliefs among the English. Attempting to identify who was a Lollard has often led historians to look at the trial records of those accused of being Lollards. One aspect overlooked in these studies is the role civic authorities, like the mayor of a town, played in the heresy trials of suspected Lollards. Contrary to existing beliefs that the Lollards were marginalized figures, the mayors' willingness to defend them against Church prosecution implies that either Lollard sympathies were more widespread than previously noted or Lollards were being inaccurately identified in the court records. This contradicts scholars' previous view that English religious views were clearly divided between Lollards and non-Lollards, providing depth and additional support to very recent work emphasizing the complexity of religious identity during the period immediately preceding the Reformation.B.A.
Bachelors
Arts and Humanities
History
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Mei, Yuan Ph D. Massachusetts Institute of Technology. "The SPRAWL distributed stream dissemination system." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97808.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 125-130).
Many large financial, news, and social media companies process and stream large quantities of data to customers, either through the public Internet or on their own internal networks. These customers often depend on that data being delivered in a timely and resource-efficient manner. In addition, many customers subscribe to the same or similar data products (e.g., particular types of financial feeds, or feeds of specific social media users). A naive implementation of a data dissemination network like this will cause redundant data to be processed and delivered repeatedly, wasting CPU and bandwidth, increasing network delays, and driving up costs. In this dissertation, we present SPRAWL, a distributed stream processing layer to address the wide-area data processing and dissemination problem. SPRAWL provides two key functions. First, it is able to generate a shared and distributed multi-query plan that transmits records through the network just once, and shares the computation of streaming operators that operate on the same subset of data. Second, it is able to compute an in-network placement of complex queries (each with dozens of operators) in wide-area networks (consisting of thousands of nodes). This placement is optimal within polynomial time and memory complexity when there are no resource (CPU, bandwidth) or query (latency) constraints. In addition, we develop several heuristics to guarantee the placement is near optimal when constraints are violated, and experimentally evaluate the performance of our algorithms versus an exhausting algorithm. We also design and implement a distributed version of the SPRAWL placement algorithm in order to support wide-area networks consisting of thousands of nodes, which centralized algorithms cannot handle. Finally, we show that SPRAWL can make complex query placement decisions on wide-area networks within seconds, and the placement can increase throughput by up to a factor of 5 and reduce dollar costs by a factor of 6 on a financial data stream processing task.
by Yuan Mei.
Ph. D.
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Haeupler, Bernhard. "Probabilistic methods for distributed information dissemination." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82349.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 457-484).
The ever-increasing growth of modern networks comes with a paradigm shift in network operation. Networks can no longer be abstracted as deterministic, centrally controlled systems with static topologies but need to be understood as highly distributed, dynamic systems with inherent unreliabilities. This makes many communication, coordination and computation tasks challenging and in many scenarios communication becomes a crucial bottleneck. In this thesis, we develop new algorithms and techniques to address these challenges. In particular we concentrate on broadcast and information dissemination tasks and introduce novel ideas on how randomization can lead to powerful, simple and practical communication primitives suitable for these modern networks. In this endeavor we combine and further develop tools from different disciplines trying to simultaneously addresses the distributed, information theoretic and algorithmic aspects of network communication. The two main probabilistic techniques developed to disseminate information in a network are gossip and random linear network coding. Gossip is an alternative to classical flooding approaches: Instead of nodes repeatedly forwarding information to all their neighbors, gossiping nodes forward information only to a small number of (random) neighbors. We show that, when done right, gossip disperses information almost as quickly as flooding, albeit with a drastically reduced communication overhead. Random linear network coding (RLNC) applies when a large amount of information or many messages are to be disseminated. Instead of routing messages through intermediate nodes, that is, following a classical store-and-forward approach, RLNC mixes messages together by forwarding random linear combinations of messages. The simplicity and topology-obliviousness of this approach makes RLNC particularly interesting for the distributed settings considered in this thesis. Unfortunately the performance of RLNC was not well understood even for the simplest such settings. We introduce a simple yet powerful analysis technique that allows us to prove optimal performance guarantees for all settings considered in the literature and many more that were not analyzable so far. Specifically, we give many new results for RLNC gossip algorithms, RLNC algorithms for dynamic networks, and RLNC with correlated data. We also provide a novel highly efficient distributed implementation of RLNC that achieves these performance guarantees while buffering only a minimal amount of information at intermediate nodes. We then apply our techniques to improve communication primitives in multi-hop radio networks. While radio networks inherently support broadcast communications, e.g., from one node to all surrounding nodes, interference of simultaneous transmissions makes multihop broadcast communication an interesting challenge. We show that, again, randomization holds the key for obtaining simple, efficient and distributed information dissemination protocols. In particular, using random back-off strategies to coordinate access to the shared medium leads to optimal gossip-like communications and applying RLNC achieves the first throughput-optimal multi-message communication primitives. Lastly we apply our probabilistic approach for analyzing simple, distributed propagation protocols in a broader context by studying algorithms for the Lovász Local Lemma. These algorithms find solutions to certain local constraint satisfaction problems by randomly fixing and propagating violations locally. Our two main results show that, firstly, there are also efficient deterministic propagation strategies achieving the same and, secondly, using the random fixing strategy has the advantage of producing not just an arbitrary solution but an approximately uniformly random one. Both results lead to simple, constructions for a many locally consistent structures of interest that were not known to be efficiently constructable before.
by Bernhard Haeupler.
Ph.D.
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HERRERA, TAPIA JORGE. "Improving Message Dissemination in Opportunistic Networks." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/86129.
Full textAbstract:
Data transmission has become a need in various fields, like in social networks with the diverse interaction applications, or in the scientific and engineering areas where for example the use of sensors to capture data is growing, or in emergency situations where there is the imperative need to have a communication system to coordinate rescue operations. Wireless networks have been able to solve these issues to a great extent, but what can we do when a fixed supporting infrastructure is not available or becomes inoperative because of saturation? Opportunistic wireless networks are an alternative to consider in these situations, since their operation does not depend on the existence of a telecommunications infrastructure but they provide connectivity through the organized cooperation of users.
This research thesis focuses on these types of networks and is aimed at improving the dissemination of information in opportunistic networks analyzing the main causes that influence the performance of data transmission. Opportunistic networks do not depend on a fixed topology but depend on the number and mobility of users, the type and quantity of information generated and sent, as well as the physical characteristics of the mobile devices that users have to transmit the data. The combination of these elements impacts on the duration of the contact time between mobile users, directly affecting the information delivery probability.
This thesis starts by presenting a thorough "state of the art" study where we present the most important contributions related to this area and the solutions offered for the evaluation of the opportunistic networks, such as simulation models, routing protocols, simulation tools, among others. After offering this broad background, we evaluate the consumption of the resources of the mobile devices that affect the performance of the the applications of opportunistic networks, both from the energetic and the memory point of view.
Next, we analyze the performance of opportunistic networks considering either pedestrian and vehicular environments. The studied approaches include the use of additional fixed nodes and different data transmission technologies, to improve the duration of the contact between mobile devices.
Finally, we propose a diffusion scheme to improve the performance of data transmission based on extending the duration of the contact time and the likelihood that users will collaborate in this process. This approach is complemented by the efficient management of the resources of the mobile devices.La transmisión de datos se ha convertido en una necesidad en diversos ámbitos, como en las redes sociales con sus diversas aplicaciones, o en las áreas científicas y de ingeniería donde, por ejemplo, el uso de sensores para capturar datos está creciendo, o en situaciones de emergencia donde impera la necesidad de tener un sistema de comunicación para coordinar las operaciones de rescate. Las redes inalámbricas actuales han sido capaces de resolver estos problemas en gran medida, pero ¿qué podemos hacer cuando una infraestructura de soporte fija no está disponible o estas se vuelven inoperantes debido a la saturación de peticiones de red? Las redes inalámbricas oportunísticas son una alternativa a considerar en estas situaciones, ya que su funcionamiento no depende de la existencia de una infraestructura de telecomunicaciones sino que la conectividad es a través de la cooperación organizada de los usuarios. Esta tesis de investigación se centra en estos tipos de redes oportunísticas y tiene como objetivo mejorar la difusión de información analizando las principales causas que influyen en el rendimiento de la transmisión de datos. Las redes oportunísticas no dependen de una topología fija, sino que dependen del número y la movilidad de los usuarios, del tipo y cantidad de información generada y enviada, así como de las características físicas de los dispositivos móviles que los usuarios tienen para transmitir los datos. La combinación de estos elementos influye en la duración del tiempo de contacto entre usuarios móviles, afectando directamente a la probabilidad de entrega de información. Esta tesis comienza presentando un exhaustivo estudio del ``estado del arte", donde presentamos las contribuciones más importantes relacionadas con esta área y las soluciones existentes para la evaluación de las redes oportunísticas, tales como modelos de simulación, protocolos de enrutamiento, herramientas de simulación, entre otros. Tras ofrecer esta amplia compilación de investigaciones, se evalúa el consumo de recursos de los dispositivos móviles que afectan al rendimiento de las aplicaciones de redes oportunísticas, desde el punto de vista energético así como de la memoria. A continuación, analizamos el rendimiento de las redes oportunísticas considerando tanto los entornos peatonales como vehiculares. Los enfoques estudiados incluyen el uso de nodos fijos adicionales y diferentes tecnologías de transmisión de datos, para mejorar la duración del contacto entre dispositivos móviles. Finalmente, proponemos un esquema de difusión para mejorar el rendimiento de la transmisión de datos basado en la extensión de la duración del tiempo de contacto, y de la probabilidad de que los usuarios colaboren en este proceso. Este enfoque se complementa con la gestión eficiente de los recursos de los dispositivos móviles.
La transmissió de dades s'ha convertit en una necessitat en diversos àmbits, com ara en les xarxes socials amb les diverses aplicacions d'interacció, o en les àrees científiques i d'enginyeria, en les quals, per exemple, l'ús de sensors per a capturar dades creix en l'actualitat, o en situacions d'emergència en què impera la necessitat de tenir un sistema de comunicació per a coordinar les operacions de rescat. Les xarxes sense fil han sigut capaces de resoldre aquests problemes en gran manera, però què podem fer quan una infraestructura de suport fixa no està disponible, o bé aquestes es tornen inoperants a causa de la saturació de peticions de xarxa? Les xarxes sense fil oportunistes són una alternativa que cal considerar en aquestes situacions, ja que el funcionament d'aquestes xarxes no depèn de l'existència d'una infraestructura de telecomunicacions, sinó que la connectivitat s'hi aconsegueix a través de la cooperació organitzada dels usuaris. Aquesta tesi de recerca se centra en aquest tipus de xarxes, i té com a objectiu millorar la difusió d'informació en xarxes oportunistes tot analitzant les principals causes que influeixen en el rendiment de la transmissió de dades. Les xarxes oportunistes no depenen d'una topologia fixa, sinó del nombre i la mobilitat dels usuaris, del tipus i la quantitat d'informació generada i enviada, i de les característiques físiques dels dispositius mòbils que els usuaris tenen per a transmetre les dades. La combinació d'aquests elements influeix en la durada del temps de contacte entre usuaris mòbils, i afecta directament la probabilitat de lliurament d'informació. Aquesta tesi comença amb un estudi exhaustiu de l'estat de la qüestió, en què presentem les contribucions més importants relacionades amb aquesta àrea i les solucions oferides per a l'avaluació de les xarxes oportunistes, com ara models de simulació, protocols d'encaminament o eines de simulació, entre d'altres. Després de mostrar aquest ampli panorama, s'avalua el consum dels recursos dels dispositius mòbils que afecten l'acompliment de les aplicacions de xarxes oportunistes, tant des del punt de vista energètic com de la memòria. A continuació, analitzem l'acompliment de xarxes oportunistes considerant tant els entorns de vianants com els vehiculars. Els enfocaments estudiats inclouen l'ús de nodes fixos addicionals i diferents tecnologies de transmissió de dades per a millorar la durada del contacte entre dispositius mòbils. Finalment, proposem un esquema de difusió per a millorar el rendiment de la transmissió de dades basat en l'extensió de la durada del temps de contacte, i de la probabilitat que els usuaris col·laboren en aquest procés. Aquest enfocament es complementa amb la gestió eficient dels recursos dels dispositius mòbils.
Herrera Tapia, J. (2017). Improving Message Dissemination in Opportunistic Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86129
TESIS
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Klaghstan, Merza. "Multimedia data dissemination in opportunistic systems." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI125/document.
Full textAbstract:
Les réseaux opportunistes sont des réseaux mobiles qui se forment spontanément et de manière dynamique grâce à un ensemble d'utilisateurs itinérants dont le nombre et le déplacement ne sont pas prévisibles. En conséquence, la topologie et la densité de tels réseaux évoluent sans cesse. La diffusion de bout-en-bout d'informations, dans ce contexte, est incertaine du fait de la forte instabilité des liens réseaux point à point entre les utilisateurs. Les travaux qui en ont envisagé l'usage visent pour la plupart des applications impliquant l'envoi de message de petite taille. Cependant, la transmission de données volumineuses telles que les vidéos représente une alternative très pertinente aux réseaux d'infrastructure, en cas d'absence de réseau, de coût important ou pour éviter la censure d'un contenu. La diffusion des informations de grande taille en général et de vidéos en particulier dans des réseaux oppnets constitue un challenge important. En effet, permettre, dans un contexte réseau très incertain et instable, au destinataire d’une vidéo de prendre connaissance au plus vite du contenu de celle-ci, avec la meilleure qualité de lecture possible et en encombrant le moins possible le réseau reste un problème encore très largement ouvert. Dans cette thèse, nous proposons un nouveau mécanisme de diffusion de vidéos dans un réseau opportuniste de faible densité, visant à améliorer le temps d'acheminement de la vidéo tout en réduisant le délai de lecture à destination. La solution proposée se base sur le choix d'encoder la vidéo en utilisant l'encodage SVC, grâce auquel la vidéo se décline en un ensemble de couches interdépendantes (layers), chacune améliorant la précédente soit en terme de résolution, soit en terme de densité, soit en terme de perception visuelle. Notre solution se décline en trois contributions. La première consiste à proposer une adaptation du mécanisme de diffusion Spray-and-Wait, avec comme unités de diffusion, les couches produites par SVC. Les couches sont ainsi diffusées avec un niveau de redondance propre à chacune, adapté à leur degré d'importance dans la diffusion de la vidéo. Notre seconde contribution consiste à améliorer le mécanisme précédent en prenant en compte une granularité plus fine et adaptative en fonction de l'évolution de la topologie du réseau. Cette amélioration a la particularité de ne pas engendrer de coût de partitionnement, les couches vidéos dans l'encodage SVC étant naturellement déclinées en petites unités (NALU) à base desquelles l'unité de transfert sera calculée. Enfin, la troisième contribution de cette thèse consiste à proposer un mécanisme hybride de complétion des couches vidéos arrivées incomplètes à destination. Cette méthode se caractérise par le fait d'être initiée par le destinataire. Elle combine un protocole de demande des parties manquantes aux usagers proches dans le réseau et des techniques de complétion de vidéo à base d’opérations sur les frames constituant la vidéoOpportunistic networks are human-centric mobile ad-hoc networks, in which neither the topology nor the participating nodes are known in advance. Routing is dynamically planned following the store-carry-and-forward paradigm, which takes advantage of people mobility. This widens the range of communication and supports indirect end-to-end data delivery. But due to individuals’ mobility, OppNets are characterized by frequent communication disruptions and uncertain data delivery. Hence, these networks are mostly used for exchanging small messages like disaster alarms or traffic notifications. Other scenarios that require the exchange of larger data are still challenging due to the characteristics of this kind of networks. However, there are still multimedia sharing scenarios where a user might need switching to an ad-hoc alternative. Examples are the cases of 1) absence of infrastructural networks in far rural areas, 2) high costs due limited data volumes or 3) undesirable censorship by third parties while exchanging sensitive content. Consequently, we target in this thesis a video dissemination scheme in OppNets. For the video delivery problem in the sparse opportunistic networks, we propose a solution that encloses three contributions. The first one is given by granulating the videos at the source node into smaller parts, and associating them with unequal redundancy degrees. This is technically based on using the Scalable Video Coding (SVC), which encodes a video into several layers of unequal importance for viewing the content at different quality levels. Layers are routed using the Spray-and-Wait routing protocol, with different redundancy factors for the different layers depending on their importance degree. In this context as well, a video viewing QoE metric is proposed, which takes the values of the perceived video quality, delivery delay and network overhead into consideration, and on a scalable basis. Second, we take advantage of the small units of the Network Abstraction Layer (NAL), which compose SVC layers. NAL units are packetized together under specific size constraints to optimize granularity. Packets sizes are tuned in an adaptive way, with regard to the dynamic network conditions. Each node is enabled to record a history of environmental information regarding the contacts and forwarding opportunities, and use this history to predict future opportunities and optimize the sizes accordingly. Lastly, the receiver node is pushed into action by reacting to missing data parts in a composite backward loss concealment mechanism. So, the receiver asks first for the missing data from other nodes in the network in the form of request-response. Then, since the transmission is concerned with video content, video frame loss error concealment techniques are also exploited at the receiver side. Consequently, we propose to combine the two techniques in the loss concealment mechanism, which is enabled then to react to missing data parts
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Suemnicht, Brett E. "GenderFail: The Queer Ethics of Dissemination." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5402.
Full textAbstract:
My research is centered upon my ongoing project GenderFail, a publishing and programming initiative featuring the perspectives of queer and trans people and people of color. GenderFail: The Queer Ethics of Dissemination is a collection of writings on queer collaboration, archiving as a collective act, and publishing as a site of queer community. The following text also illustrates the importance of creating and maintaining an intersectional platform as a non-binary white queer subject. I examine and define the role of “queer identity” in my own work while mapping the history of failure by white queers, including myself, in the of articulation of intersectionality. By understanding how intersectionality is important in a queer-focused collaborative practice, I seek to emphasize the messiness of citation, collaboration, and community in relation to my discursive uses of printed matter.
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Baez, Marcos. "Knowledge Dissemination in the Web Era." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/368384.
Full textAbstract:
In this research work we address the limitations of the current scientic knowledge dissemination model to face the new scenario posed by the Web. We explore the historical reasons behind the current model, and we show that it is essentially the same today, even if the Web has made dissemination nearly real time and free. We show how this misalignment between the current model and Web capabilities brings not only missed opportunities but also a serious overload problem, creating diculties for authors to gain visibility, and for readers to nd interesting content. Our approach has been to build from the ground up, by i) understanding how the very core concepts of the scientic publishing such as "scientic contribution", "scientic journal" and even "reputation" should adapt to the new scenario; ii) studying the dissemination and sharing practices that are inherently present in the scientic community, to understand how technology can empower those practices to reduce information overload. The outcome is novel models, tools and a platform for knowledge dissemination that takes full advantage of the Web while addressing the overload problem.
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Baez, Marcos. "Knowledge Dissemination in the Web Era." Doctoral thesis, University of Trento, 2012. http://eprints-phd.biblio.unitn.it/902/1/baez-thesis.pdf.
Full textAbstract:
In this research work we address the limitations of the current scientic knowledge dissemination model to face the new scenario posed by the Web.
We explore the historical reasons behind the current model, and we show that it is essentially the same today, even if the Web has made dissemination nearly real time and free. We show how this misalignment between the current model and Web capabilities brings not only missed opportunities but also a serious overload problem, creating diculties for authors to gain visibility, and for readers to nd interesting content. Our approach has been to build from the ground up, by i) understanding how the very core concepts of the scientic publishing such as "scientic contribution", "scientic journal" and even "reputation" should adapt to the new scenario; ii) studying the dissemination and sharing practices that are inherently present in the scientic community, to understand how technology can empower those practices to reduce information overload. The outcome is novel models, tools and a platform for knowledge dissemination that takes full advantage of the Web while addressing the overload problem.
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Li, Yingjie. "Information dissemination and routing in communication networks." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1132767756.
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Metaferia, Gohe Amhayesus. "Daily Climate Change Data Generation and Dissemination." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32457.
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The worldwide challenges to achieve cost effective protection against global warming impacts and to acquire reliable decision making tools continually force new developments in the area of climate change research. Climate change impacts projections involve several steps: emission scenarios generation, Global Circulation Models and Regional Climate Models (GCM/RCM) runs, downscaling, impact model running, analysis of results and decision making.
Unfortunately, GCM/RCMs outputs are often biased and need to be processed before being fed into impact models. This thesis describes the effort carried out to alleviate the burden of downscaling coarse hydro-climatology data outputs from GCM/RCM and making results readily available for climate change impact analysis for specific regions, particularly in the African continent. GCM/RCM outputs are highly unreliable at the sub-grid scale to be used for region specific
impact analysis (Wilby, Hay, & Leavesly, 1999). Furthermore, raw GCM/RCM outputs are often downscaled under the premises that the latter offer very coarse spatial resolution. The Internet is a common resource for users of climate change data to access relevant information. Web-based interfaces offer users the capability to retrieve such data. This thesis involves the development of a new web-portal, which addresses the demand for climate change data at the daily scale. It is a user-friendly interactive web-based interface with
multiple functionalities including: capacity to process information, capacity to search, sort, retrieve and filter data and download features. Six climate variables are considered in this project: precipitation, maximum temperature, minimum temperature, wind speed, relative humidity and solar radiation. The aforementioned climate variables have been downscaled to specific geographical locations and results have been made available at a fine temporal
resolution – the daily scale. The data portal currently hosts climate change data for nine stations in western Africa: Agadez, Brini N’Konni, Gaya, Maine Soroa, Maradi Airport, Niamey Airport, Tahoua, Tillabery and Zinder Airport. The above mentioned climate stations are all located in Niger. Nonetheless, the project aims to expand and cover further ground in Africa. Quantile - Quantile downscaling, also known as Quantile-Quantile mapping, matching or
transformation is a statistical procedure used in this project to downscale raw GCM/RCM outputs. GCM/RCM outputs from the AMMA-Ensemble sets under the SRES A1B scenario were used as raw data.
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Huang, Leijun. "Reliable bulk data dissemination in sensor networks." Fairfax, VA : George Mason University, 2007. http://hdl.handle.net/1920/2942.
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Thesis (Ph. D.)--George Mason University, 2007.Title from PDF t.p. (viewed Jan. 18, 2008). Thesis director: Sanjeev Setia. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science. Vita: p. 117. Includes bibliographical references (p. 112-116). Also available in print.
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Miao, Jingwei. "Message dissemination in mobile delay tolerant networks." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00876589.
Full textAbstract:
Mobile Delay Tolerant Networks (MDTNs) are wireless mobile networks in which a complete routing path between two nodes that wish to communicate cannot be guaranteed. A number of networking scenarios have been categorized as MDTNs, such as vehicular ad hoc networks, pocket switched networks, etc. The network asynchrony, coupled with the limited resources of mobile devices make message dissemination (also called routing) one of the fundamental challenges in MDTNs. In the literature, a large body of work has been done to deal with routing in MDTNs. However, most of the existing routing protocols are based on at least one of the following three assumptions: (1) all messages can be routed by relying on a single mobility property; (2) all messages can be routed using a single message allocation strategy; (3) users are willing to disclose their mobility information and relationships to others in order to improve the quality of the routing. We argue that the above three assumptions are not realistic because: (1) users can exhibit various social behaviors and consequently various mobility properties (e.g., they can have regular movements during week-days and exhibit non-predictable movements during week-ends); (2) some messages might need more or less copies to be delivered according to the localization of the source and the destination and to the urgency of the message; and (3) users mobility data can disclose sensitive information about the users. In this thesis, we relieve MDTN routing from the above three restrictive assumptions. Firstly, we propose an adaptive routing protocol for mobile delay tolerant networks. The proposed protocol can dynamically learn the social properties of nodes based on their mobility patterns, and exploit the most appropriate routing strategy each time an intermediate node is encountered. Simulations performed on real mobility traces show that our protocol achieves a better delivery ratio than existing state-of-the-art routing protocols that rely on a single mobility property. Secondly, we present a delay and cost balancing protocol for efficient routing in mobile delay tolerant networks. The presented protocol reasons on the remaining time-to-live of a message to dynamically allocate the minimum number of copies that are necessary to achieve a given delivery probability. Evaluation results show that the protocol can achieve a good balance between message delivery delay and delivery cost, compared with most of the existing routing protocols in the literature. Lastly, we propose an efficient privacy preserving prediction-based routing protocol for mobile delay tolerant networks. This protocol preserves the mobility patterns of a node from being disclosed by exploiting the mobility pattern of communities that node belongs to. Evaluation results demonstrate that this protocol can obtain comparable routing performance to prediction-based protocols while preserving the mobility pattern of nodes.
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AGARWAL, Rachit. "Towards enhancing information dissemination in wireless networks." Phd thesis, Institut National des Télécommunications, 2013. http://tel.archives-ouvertes.fr/tel-00919417.
Full textAbstract:
In public warning message systems, information dissemination across the network is a critical aspect that has to be addressed. Dissemination of warning messages should be such that it reaches as many nodes in the network in a short time. In communication networks those based on device to device interactions, dissemination of the information has lately picked up lot of interest and the need for self organization of the network has been brought up. Self organization leads to local behaviors and interactions that have global effects and helps in addressing scaling issues. The use of self organized features allows autonomous behavior with low memory usage. Some examples of self organization phenomenon that are observed in nature are Lateral Inhibition and Flocking. In order to provide self organized features to communication networks, insights from such naturally occurring phenomenon is used. Achieving small world properties is an attractive way to enhance information dissemination across the network. In small world model rewiring of links in the network is performed by altering the length and the direction of the existing links. In an autonomous wireless environment such organization can be achieved using self organized phenomenon like Lateral inhibition and Flocking and beamforming (a concept in communication). Towards this, we first use Lateral Inhibition, analogy to Flocking behavior and beamforming to show how dissemination of information can be enhanced. Lateral Inhibition is used to create virtual regions in the network. Then using the analogy of Flocking rules, beam properties of the nodes in the regions are set. We then prove that small world properties are achieved using average path length metric. However, the proposed algorithm is applicable to static networks and Flocking and Lateral Inhibition concepts, if used in a mobile scenario, will be highly complex in terms of computation and memory. In a mobile scenario such as human mobility aided networks, the network structure changes frequently. In such conditions dissemination of information is highly impacted as new connections are made and old ones are broken. We thus use stability concept in mobile networks with beamforming to show how information dissemination process can be enhanced. In the algorithm, we first predict the stability of a node in the mobile network using locally available information and then uses it to identify beamforming nodes. In the algorithm, the low stability nodes are allowed to beamform towards the nodes with high stability. The difference between high and low stability nodes is based on threshold value. The algorithm is developed such that it does not require any global knowledge about the network and works using only local information. The results are validated using how quickly more number of nodes receive the information and different state of the art algorithms. We also show the effect of various parameters such as number of sources, number of packets, mobility parameters and antenna parameters etc. on the information dissemination process in the network. In realistic scenarios however, the dynamicity in the network is not only related to mobility. Dynamic conditions also arise due to change in density of nodes at a given time. To address effect of such scenario on the dissemination of information related to public safety in a metapopulation, we use the concepts of epidemic model, beamforming and the countrywide mobility pattern extracted from the $D4D$ dataset. Here, we also propose the addition of three latent states to the existing epidemic model ($SIR$ model). We study the transient states towards the evolution of the number of devices having the information and the difference in the number of devices having the information when compared with different cases to evaluate the results. Through the results we show that enhancements in the dissemination process can be achieved in the addressed scenario
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Bako, Boto [Verfasser]. "Efficient information dissemination in VANETs / Boto Bako." Ulm : Universität Ulm, 2016. http://d-nb.info/1122195583/34.
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Greede, Abdolbast. "Data dissemination in partially cooperative opportunistic networks." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/56929/.
Full textAbstract:
Wireless communication between mobile users has become more popular than ever in the last decade, leading to increasing demand for network infrastructure. The growing popularity of smartphones among mobile users, leads an alternative infrastructure-less networking paradigm known as opportunistic networks. In opportunistic networks, mobile nodes such as smartphones use the mobility of devices in addition to wireless forwarding between intermediate nodes to facilitate communication without requiring a simultaneous path between source and destination. Without guaranteed connectivity, the strategy for data delivery is a key research challenge for such networks. In this research, we present the design and evaluation of the Repository-based Data Dissemination (RDD) system, a communication system which does not rely on cooperation from mobile nodes but instead employs a small number of well-placed standalone fixed devices (named repositories) to facilitate data dissemination. To find the optimal location for their repositories, RDD employs knowledge of the mobility characteristics of mobile users. To evaluate RDD, a new mobility model “Human mobility model” has been designed, which was able to closely mimic the users’ real mobility, and proven by conducting a series of experiments compared with real mobility traces. Using this model, the performance of the RDD is evaluated using custom simulation. In comparison with epidemic routing, the results show that RDD is able to drastically reduce resource consumption, expressed in terms of message redundancy, while preserving the performance in terms of data object delivery.
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Coleman, Todd P. (Todd Prentice) 1977. "Low-complexity approaches to distributed data dissemination." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35286.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 145-153).
In this thesis we consider practical ways of disseminating information from multiple senders to multiple receivers in an optimal or provably close-to-optimal fashion. The basis for our discussion of optimal transmission of information is mostly information theoretic - but the methods that we apply to do so in a low-complexity fashion draw from a number of different engineering disciplines. The three canonical multiple-input, multiple-output problems we focus our attention upon are: * The Slepian-Wolf problem where multiple correlated sources must be distributedly compressed and recovered with a common receiver. * The discrete memoryless multiple access problem where multiple senders communicate across a common channel to a single receiver. * The deterministic broadcast channel problem where multiple messages are sent from a common sender to multiple receivers through a deterministic medium. Chapter 1 serves as an introduction and provides models, definitions, and a discussion of barriers between theory and practice for the three canonical data dissemination problems we will discuss. Here we also discuss how these three problems are all in different senses 'dual' to each other, and use this as a motivating force to attack them with unifying themes.
(cont.) Chapter 2 discusses the Slepian-Wolf problem of distributed near-lossless compression of correlated sources. Here we consider embedding any achievable rate in an M-source problem to a corner point in a 2M - 1-source problem. This allows us to employ practical iterative decoding techniques and achieve rates near the boundary with legitimate empirical performance. Both synthetic data and real correlated data from sensors at the International Space Station are used to successfully test our approach. Chapter 3 generalizes the investigation of practical and provably good decoding algorithms for multiterminal systems to the case where the statistical distribution of the memoryless system is unknown. It has been well-established in the theoretical literature that such 'universal' decoders exist and do not suffer a performance penalty, but their proposed structure is highly nonlinear and therefore believed to be complex. For this reason, most discussion of such decoders has been limited to the realm of ontology and proof of existence. By exploiting recently derived results in other engineering disciplines (i.e. expander graphs, linear programming relaxations, etc), we discuss a code construction and two decoding algorithms that have polynomial complexity and admit provably good performance (exponential error probability decay).
(cont.) Because there is no need for a priori statistical knowledge in decoding (which in many settings - for instance a sensor network - might be difficult to repeatedly acquire without significant cost), this approach has very attractive robustness, energy efficiency, and stand-alone practical implications. Finally, Chapter 4 walks away from the multiple-sender, single-receiver setting and steps into the single-sender-multiple receiver setting. We focus our attention here on the deterministic broadcast channel, which is dual to the Slepian-Wolf and multiple access problems in a number of ways - including how the difficulty of practical implementation lies in the encoding rather than decoding. Here we illustrate how again a splitting approach can be applied, and how the same properties from the Slepian-Wolf and multiple access splitting settings remain. We also discuss practical coding strategies for some problems motivated by wireless, and show how by properly 'dualizing' provably good decoding strategies for some channel coding problems, we admit provably good encoding for this setting.
by Todd Prentice Coleman.
Ph.D.
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Wang, John (John Michael) 1976. "Information aggregation and dissemination in simulated markets." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80140.
Full textAbstract:
Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (leaf 39).
by John Wang.
S.B.and M.Eng.
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Jahanbakhsh, Mashhadi A. "Content dissemination in participatory delay tolerant networks." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1306721/.
Full textAbstract:
As experience with the Web 2.0 has demonstrated, users have evolved from being only consumers of digital content to producers. Powerful handheld devices have further pushed this trend, enabling users to consume rich media (for example, through high resolution displays), as well as create it on the go by means of peripherals such as built-in cameras. As a result, there is an enormous amount of user-generated content, most of which is relevant only within local communities. For example, students advertising events taking place around campus. For such scenarios, where producers and consumers of content belong to the same local community, networks spontaneously formed on top of colocated user devices can offer a valid platform for sharing and disseminating content. Recently, there has been much research in the field of content dissemination in mobile networks, most of which exploits user mobility prediction in order to deliver messages from the producer to the consumer, via spontaneously formed Delay Tolerant Networks (DTNs). Common to most protocols is the assumption that users are willing to participate in the content distribution network; however, because of the energy restrictions of handheld devices, users’ participation cannot be taken for granted. In this thesis, we design content dissemination protocols that leverage information about user mobility, as well as interest, in order to deliver content, while avoiding overwhelming noninterested users. We explicitly reason about battery consumption of mobile devices to model participation, and achieve fairness in terms of workload distribution. We introduce a dynamic priority scheduling framework, which enables the network to allocate the scarce energy resources available to support the delivery of the most desired messages. We evaluate this work extensively by means of simulation on a variety of real mobility traces and social networks, and draw a comparative evaluation with the major related works in the field.
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Leontiadis, I. "A content dissemination framework for vehicular networking." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19493/.
Full textAbstract:
Vehicular Networks are a peculiar class of wireless mobile networks in which vehicles are equipped with radio interfaces and are, therefore, able to communicate with fixed infrastructure (if available) or other vehicles. Content dissemination has a potential number of applications in vehicular networking, including advertising, traffic warnings, parking notifications and emergency announcements. This thesis addresses two possible dissemination strategies: i) Push-based that is aiming to proactively deliver information to a group of vehicles based on their interests and the level of matching content, and ii) Pull-based that is allowing vehicles to explicitly request custom information. Our dissemination framework is taking into consideration very specific information only available in vehicular networks: the geographical data produced by the navigation system. With its aid, a vehicle's mobility patterns become predictable. This information is exploited to efficiently deliver the content where it is needed. Furthermore, we use the navigation system to automatically filter information which might be relevant to the vehicles. Our framework has been designed and implemented in .NET C# and Microsoft MapPoint. It was tested using a small number of vehicles in the area of Cambridge, UK. Moreover, to prove the correctness of our protocols, we further evaluated it in a large-scale network simulation over a number of realistic vehicular trace-based scenarios. Finally, we built a test-case application aiming to prove that vehicles can gain from such a framework. In this application every vehicle collects and disseminates road traffic information. Vehicles that receive this information can individually evaluate the traffic conditions and take an alternative route, if needed. To evaluate this approach, we collaborated with UCLA's Network Research Lab (NRL), to build a simulator that combines network and dynamic mobility emulation simultaneously. When our dissemination framework is used, the drivers can considerably reduce their trip-times.
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Thorn, Nicholas. "The dissemination of the Middle English Psalter." Thesis, University of Birmingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595688.
Full textAbstract:
This thesis examines the Middle English vernacular psalm-versions, and considers their social context. It examines the uses to which vernacular psalm-texts were put, ranging from that of orthodox affective piety to 'popular' folk-religion. Twenty-five texts are discussed, some previously ignored; four such psalm-texts are presented in the Appendices. A further five pseudo-abbreviated psal ter~, which recommend the non-liturgical use of psalms by the laity, are also transcribed here. The relationship between the English and Latin in the texts is re-examined. Whereas it has been argued that the English in such texts was usually subsidiary to the Latin, this thesis demonstrates that many English versions were designed to be read without recourse to the Vulgate. These translations of the Psalms provided the laity with their own vernacular liturgy which they used both privately and during formal acts of worship. The rise of the free-verse psalm-paraphrase in the late-fourteenth century led to specifically Christological interpretations, a process which was reinforced when biblical translation was banned in the early-fifteenth century. The development of prose abbreviations has previously been ignored; their range and popularity are explored here for the first time.
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Maryokhin, Tymur. "Data dissemination in large-cardinality social graphs." Thesis, Linnéuniversitetet, Institutionen för datavetenskap (DV), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-48268.
Full textAbstract:
Near real-time event streams are a key feature in many popular social media applications. These types of applications allow users to selectively follow event streams to receive a curated list of real-time events from various sources. Due to the emphasis on recency, relevance, personalization of content, and the highly variable cardinality of social subgraphs, it is extremely difficult to implement feed following at the scale of major social media applications. This leads to multiple architectural approaches, but no consensus has been reached as to what is considered to be an idiomatic solution. As of today, there are various theoretical approaches exploiting the dynamic nature of social graphs, but not all of them have been applied in practice. In this paper, large-cardinality graphs are placed in the context of existing research to highlight the exceptional data management challenges that are posed for large-scale real-time social media applications. This work outlines the key characteristics of data dissemination in large-cardinality social graphs, and overviews existing research and state-of-the-art approaches in industry, with the goal of stimulating further research in this direction.
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Chu, I.-Hsine (Jack). "CONTOUR GUIDED DISSEMINATION FOR NETWORKED EMBEDDED SYSTEMS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1159522840.
Full text
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Duan, Minlan. "Quality of Service in Contour Guided Dissemination." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1184805314.
Full text
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Mamidisetty, Kranthi Kumar. "Generalizing Contour Guided Dissemination in Mesh Topologies." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1208206994.
Full text
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Pereira, João Pedro Ferreira e. "Dissemination of contextual information for assisted driving." Master's thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/23520.
Full textAbstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesDriver assistance systems can be used to improve road and car safety, reduce driving fatigue and provide a more e cient driving experience. An important part of these systems is the communication between vehicles, and vehicle-to-infrastructure communication. This work presents mechanisms enabling driving support, exploring the vehicular network to provide information about the drivers neighborhood. The network is composed by vehicles, tra c signals and xed stations along the road. Each car is equipped with a recording camera, a GPS receiver, as well as communication modules such as WiFi, WAVE and 3G/4G, allowing the exchange of data between the various nodes. The data exchanged is composed by positional data of neighboring vehicles, sensor information from tra c signals and video images incoming from other vehicles. This data is used to facilitate the driver in decision making, but can also provide an overview of the tra c density in the neighborhood. The tra c signals broadcast their position and if they are dynamic (such as tra c lights), their status is also transmitted. The xed stations are equipped with numerous sensors and are used to provide environmental data. The driver can access all the collected data via visual information, on a display screen that contains a map of the neighborhood along with the information available of the nearby nodes. The proposed system is evaluated through real vehicular experiments in two distinct scenarios: urban and highway. The results show that the communication delay is higher in the highway scenario, mainly due to the distance between vehicles and travelling speeds. However, promising results regarding the maximum delay and the average number of retransmissions foresee important inputs for future services of assisted-driving, in general, and carovertaking assistance, in particular.
Os sistemas de condução assistida podem ser utilizados para melhorar a segurança rodoviária e automóvel, reduzir a fadiga da condução e proporcionar uma experiência de condução mais e ciente. Uma parte importante desses sistemas e a comunicação entre veículos e comunicação veiculo infraestrutura. Este trabalho propõe mecanismos que permitem o suporte a condução, explorando a rede de veicular para fornecer informações sobre a vizinhança do condutor. A rede e composta por veículos, sinais de transito e estações fixas ao longo da estrada. Cada carro esta equipado com uma camera de gravação, um receptor GPS, bem como módulos de comunicação, como WiFi, WAVE e 3G/4G, permitindo a troca de dados entre os vários nos. Os dados trocados são compostos por dados posicionais de veículos vizinhos, informações sensoriais de sinais de trânsito e imagens de vídeo provenientes de outros veículos. Esses dados s~ao usados para facilitar a tomada de decisões, mas também podem fornecer uma vis~ao geral da densidade de tráfego na vizinhança. Os sinais de transito transmitem a sua posição e, no caso de serem dinâmicos (como semáforos), o seu estado actual também e transmitido. As estações fixas estão equipadas com vários sensores e sao usadas para fornecer dados ambientais. O condutor pode aceder a todos os dados recolhidos através de informações visuais, num ecrã que contém um mapa da sua redondeza junto com a informação disponível dos nos vizinhos. O sistema proposto e avaliado através de testes reais em dois cenários distintos: urbano e auto-estrada. Os resultados mostram que o atraso da comunicação e maior no cenário da auto-estrada, principalmente devido as maiores distancias entre os veículos e as velocidades mais elevadas. No entanto, resultados promissores em relação ao atraso máximo e ao numero médio de retransmissões prevêem contribuições importantes para serviços futuros de condução assistida em geral, e assistência de ultrapassagem de veículos, em particular.
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Cirnigliaro, Giulio. "Data dissemination on overlay networks through gossip." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5610/.
Full textAbstract:
Gossip protocols have been analyzed as a feasible solution for data dissemination on peer-to-peer networks. In this thesis, a new data dissemination protocol is proposed and compared with other known gossip mechanisms. Performance evaluation is based on simulation.
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Berti, Gianmarco. "Data dissemination over complex networks through gossip." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8154/.
Full textAbstract:
This thesis offers a practical and theoretical evaluations about gossip-epidemic algorithms, comparing those most common in the literature with new proposed algorithms and analyzing their behavior.
Tests have been executed using one hundred graphs that has been randomly generated by Large Unstructured NEtwork Simulator (LUNES), a simulation software provided by Parallel and Distributed Simulation Research Group (PADS), of the Department of Computer Science, Università di Bologna and simulated using Advanced RTI System (ARTÌS), based on the High Level Architecture standard.
Literatures algorithms have been analyzed and taken as base for new algorithms.
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GRILLI, GIANLUCA. "Data dissemination in vehicular ad-hoc networks." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1434.
Full textAbstract:
Il processo di "data dissemination" consiste nella diffusione dell'informazione attraverso i diversi nodi che costituiscono la rete e comprende una molteplicità di aspetti che destano interesse nella comunità scientifica.
Lo sviluppo di sistemi efficienti per i processi di "data dissemination" nelle reti veicolari (VANET) è infatti argomento di ampio dibattito nelle maggiori conferenze in ambito automotive, a fronte delle problematiche di trasmissione legate essenzialmente alla natura broadcast delle comunicazioni e all'esigenza di pervenire ad una più efficiente gestione del canale trasmissivo, affrontando al contempo problemi di collisione e di interferenza dovuti all'ambiente circostante (urban landscape).
L'obiettivo principale di questa tesi è stato quello di analizzare i principali processi di data dissemination nel mondo VANET e sviluppare, quindi, un nuovo protocollo che dimostri al tempo stesso: efficienza, bassa latenza, alta velocità di disseminazione e buon utilizzo del canale trasmissivo.
L'idea chiave prevede l'impiego di tecniche di codifica con codici a fontana (Fountain Codes) sfruttando il paradigma di comunicazione I2V2V (infrastructure-to-vehicle-to-vehicle), in cui i veicoli e l'infrastruttura cooperano nello scambio dei dati.
I risultati ottenuti sperimentalmente hanno mostrato una buona fattibilità della soluzione prospettata, che potrebbe pertanto essere implementata su reali schede di comunicazione installate on-board sui veicoli (in ottemperanza a quanto previsto dagli Intelligent Transportation Systems, ITS).Data dissemination consists on spreading a large amount of information to all nodes belonging to a network and its peculiar characteristics make this goal particularly interesting and challenging. However, developing efficient data dissemination schemes for vehicular ad-hoc networks (VANETs) is still an open issue due to the broadcast nature of the channel and to the need of managing all data transmissions in a distributed way. The former leads to a lot of problems related to the channel contention, collisions and interference. The latter requires to define algorithms which exploit only local information of the network and which are scalable and robust to the node mobility. The focus of this thesis is to investigate the data dissemination process in VANETs by defining and developing a new communication protocol (CORP), efficient in terms of limited computational complexity, low latency, high speed of dissemination, high delivery ratio, better usage of the wireless channel and, consequently, better energy consumption. The basic idea relies on the the application of the fountain codes theory to vehicular networks in order to implement a true I2V2V (infrastructure-to-vehicle-to-vehicle ) communication paradigm. Results gathered from extensive simulation show the feasibility of such a solution, which could be implemented in real on-board communication devices for Intelligent Transportation Systems (ITS).
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Tantisantisom, Khumphicha. "Information dissemination for farming communities in Thailand." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/428.
Full textAbstract:
The use of information and communication technology tools has been applied in many disciplines, including agricultural sectors. It may be applied in many modules such as data gathering, data processing, information management and information dissemination. One issue that cannot be neglected is the readiness of technology service users, or farmers in this case. It was found that most Thai farmers were poor and illiterate; therefore, offering them the best available tools and services may not be always what they would like to use. To answer the research questions, action research methodology was selected in this study to find a practical way to deliver agricultural information to Thai farmers. Groups of participants from two villages in a northern Thai province were targeted; as a result, case study methodology was also used in this study. Accordingly, a needs analysis using a survey technique, in conjunction with an analysis of the current situation and relevant documents, was conducted in order to find answers about the types of information truly required by Thai farmers. Additionally, questions about how Thai farmers currently received agricultural information, and factors affecting their information requirements, were to be answered. Then, information dissemination through the short message service on mobile phones was found to be the most appropriate alternative for Thai farmers in this study. The free-of-charge experimental service was offered to participating farmers for a period of eight weeks. After that the user satisfaction survey and group interviews were conducted to determine the effectiveness of the system framework. A number of findings and discussion points will be useful for policy makers, relevant government agencies and other researchers who attempt to conduct viable projects in the actual field. This study revealed that income, age and education were significant factors related to the success of the agricultural information dissemination project. Also, relationships between agricultural information extension workers and farmers affected the preferences for, and attitudes to, receiving information among Thai farmers. Subsequently, a new framework was proposed and was obtained comments from agricultural extension workers in order to improve the framework for a wider scale. Finally, the main objective of this research, which was to find out how information and communication technologies can be used to enhance information dissemination to Thai farmers, was achieved. In summary, these outputs are likely to be useful and workable in practice, together with collaborations with third parties such as local councils, mobile phone service providers or academic sectors.
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Agarwal, Rachit. "Towards enhancing information dissemination in wireless networks." Thesis, Evry, Institut national des télécommunications, 2013. http://www.theses.fr/2013TELE0020/document.
Full textAbstract:
Dans les systèmes d'alertes publiques, l’étude de la diffusion des informations dans le réseau est essentielle. Les systèmes de diffusion des messages d'alertes doivent atteindre beaucoup de nœuds en peu de temps. Dans les réseaux de communication basés sur les interactions “device to device”, on s'est récemment beaucoup intéressé à la diffusion des informations et le besoin d'auto-organisation a été mis en évidence. L'auto-organisation conduit à des comportements locaux et des interactions qui ont un effet sur le réseau global et présentent un avantage de scalabilité. Ces réseaux auto-organisés peuvent être autonomes et utiliser peu d'espace mémoire. On peut développer des caractères auto-organisés dans les réseaux de communication en utilisant des idées venant de phénomènes naturels. Il semble intéressant de chercher à obtenir les propriétés des “small world” pour améliorer la diffusion des informations dans le réseau. Dans les modèles de “small world” on réalise un recâblage des liens dans le réseau en changeant la taille et la direction des liens existants. Dans un environnement sans-fils autonome une organisation de ce type peut être créée en utilisant le flocking, l'inhibition latérale et le “beamforming”. Dans ce but, l'auteur utilise d'abord l'analogie avec l'inhibition latérale, le flocking et le “beamforming” pour montrer comment la diffusion des informations peut être améliorée. L'analogue de l'inhibition latérale est utilisé pour créer des régions virtuelles dans le réseau. Puis en utilisant l'analogie avec les règles du flocking, on caractérise les propriétés des faisceaux permettant aux nœuds de communiquer dans les régions. Nous prouvons que les propriétés des “small world” sont vérifiées en utilisant la mesure des moyennes des longueurs des chemins. Cependant l'algorithme proposé est valable pour les réseaux statiques alors que dans les cas introduisant de la mobilité, les concepts d'inhibition latérale et de flocking nécessiteraient beaucoup plus de temps. Dans le cas d'un réseau mobile la structure du réseau change fréquemment. Certaines connexions intermittentes impactent fortement la diffusion des informations. L'auteur utilise le concept de stabilité avec le “beamforming” pour montrer comment on peut améliorer la diffusion des informations. Dans son algorithme il prévoit d'abord la stabilité du nœud en utilisant des informations locales et il utilise ce résultat pour identifier les nœuds qui réaliseront du beamforming. Dans l'algorithme, les nœuds de stabilité faible sont autorisés à faire du beamforming vers les nœuds de forte stabilité. La frontière entre forte et faible stabilité est fixée par un seuil. Cet algorithme ne nécessite pas une connaissance globale du réseau, mais utilise des données locales. Les résultats sont validés en étudiant le temps au bout duquel plus de nœuds reçoivent l'information et en comparant avec d'autres algorithmes de la littérature. Cependant, dans les réseaux réels, les changements de structure ne sont pas dus qu'à la mobilité, mais également à des changements de la densité des nœuds à un moment donné. Pour tenir compte de l'influence de tels événements sur la diffusion des informations concernant la sécurité publique, l'auteur utilise les concepts de modèle de métapopulation, épidémiologiques, “beamforming” et mobilité géographique obtenu à partir de données D4D. L'auteur propose la création de trois états latents qu'il ajoute au modèle épidémiologique connu: SIR. L'auteur étudie les états transitoires en analysant l'évolution du nombre de postes ayant reçu les informations et compare les résultats concernant ce nombre dans les différents cas. L'auteur démontre ainsi que le scenario qu'il propose permet d'améliorer le processus de diffusion des informations. Il montre aussi les effets de différents paramètres comme le nombre de sources, le nombre de paquets, les paramètres de mobilité et ceux qui caractérisent les antennes sur la diffusion des informationsIn public warning message systems, information dissemination across the network is a critical aspect that has to be addressed. Dissemination of warning messages should be such that it reaches as many nodes in the network in a short time. In communication networks those based on device to device interactions, dissemination of the information has lately picked up lot of interest and the need for self organization of the network has been brought up. Self organization leads to local behaviors and interactions that have global effects and helps in addressing scaling issues. The use of self organized features allows autonomous behavior with low memory usage. Some examples of self organization phenomenon that are observed in nature are Lateral Inhibition and Flocking. In order to provide self organized features to communication networks, insights from such naturally occurring phenomenon is used. Achieving small world properties is an attractive way to enhance information dissemination across the network. In small world model rewiring of links in the network is performed by altering the length and the direction of the existing links. In an autonomous wireless environment such organization can be achieved using self organized phenomenon like Lateral inhibition and Flocking and beamforming (a concept in communication). Towards this, we first use Lateral Inhibition, analogy to Flocking behavior and beamforming to show how dissemination of information can be enhanced. Lateral Inhibition is used to create virtual regions in the network. Then using the analogy of Flocking rules, beam properties of the nodes in the regions are set. We then prove that small world properties are achieved using average path length metric. However, the proposed algorithm is applicable to static networks and Flocking and Lateral Inhibition concepts, if used in a mobile scenario, will be highly complex in terms of computation and memory. In a mobile scenario such as human mobility aided networks, the network structure changes frequently. In such conditions dissemination of information is highly impacted as new connections are made and old ones are broken. We thus use stability concept in mobile networks with beamforming to show how information dissemination process can be enhanced. In the algorithm, we first predict the stability of a node in the mobile network using locally available information and then uses it to identify beamforming nodes. In the algorithm, the low stability nodes are allowed to beamform towards the nodes with high stability. The difference between high and low stability nodes is based on threshold value. The algorithm is developed such that it does not require any global knowledge about the network and works using only local information. The results are validated using how quickly more number of nodes receive the information and different state of the art algorithms. We also show the effect of various parameters such as number of sources, number of packets, mobility parameters and antenna parameters etc. on the information dissemination process in the network. In realistic scenarios however, the dynamicity in the network is not only related to mobility. Dynamic conditions also arise due to change in density of nodes at a given time. To address effect of such scenario on the dissemination of information related to public safety in a metapopulation, we use the concepts of epidemic model, beamforming and the countrywide mobility pattern extracted from the $D4D$ dataset. Here, we also propose the addition of three latent states to the existing epidemic model ($SIR$ model). We study the transient states towards the evolution of the number of devices having the information and the difference in the number of devices having the information when compared with different cases to evaluate the results. Through the results we show that enhancements in the dissemination process can be achieved in the addressed scenario
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Agarwal, Rachit. "Towards enhancing information dissemination in wireless networks." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2013. http://www.theses.fr/2013TELE0020.
Full textAbstract:
Dans les systèmes d'alertes publiques, l’étude de la diffusion des informations dans le réseau est essentielle. Les systèmes de diffusion des messages d'alertes doivent atteindre beaucoup de nœuds en peu de temps. Dans les réseaux de communication basés sur les interactions “device to device”, on s'est récemment beaucoup intéressé à la diffusion des informations et le besoin d'auto-organisation a été mis en évidence. L'auto-organisation conduit à des comportements locaux et des interactions qui ont un effet sur le réseau global et présentent un avantage de scalabilité. Ces réseaux auto-organisés peuvent être autonomes et utiliser peu d'espace mémoire. On peut développer des caractères auto-organisés dans les réseaux de communication en utilisant des idées venant de phénomènes naturels. Il semble intéressant de chercher à obtenir les propriétés des “small world” pour améliorer la diffusion des informations dans le réseau. Dans les modèles de “small world” on réalise un recâblage des liens dans le réseau en changeant la taille et la direction des liens existants. Dans un environnement sans-fils autonome une organisation de ce type peut être créée en utilisant le flocking, l'inhibition latérale et le “beamforming”. Dans ce but, l'auteur utilise d'abord l'analogie avec l'inhibition latérale, le flocking et le “beamforming” pour montrer comment la diffusion des informations peut être améliorée. L'analogue de l'inhibition latérale est utilisé pour créer des régions virtuelles dans le réseau. Puis en utilisant l'analogie avec les règles du flocking, on caractérise les propriétés des faisceaux permettant aux nœuds de communiquer dans les régions. Nous prouvons que les propriétés des “small world” sont vérifiées en utilisant la mesure des moyennes des longueurs des chemins. Cependant l'algorithme proposé est valable pour les réseaux statiques alors que dans les cas introduisant de la mobilité, les concepts d'inhibition latérale et de flocking nécessiteraient beaucoup plus de temps. Dans le cas d'un réseau mobile la structure du réseau change fréquemment. Certaines connexions intermittentes impactent fortement la diffusion des informations. L'auteur utilise le concept de stabilité avec le “beamforming” pour montrer comment on peut améliorer la diffusion des informations. Dans son algorithme il prévoit d'abord la stabilité du nœud en utilisant des informations locales et il utilise ce résultat pour identifier les nœuds qui réaliseront du beamforming. Dans l'algorithme, les nœuds de stabilité faible sont autorisés à faire du beamforming vers les nœuds de forte stabilité. La frontière entre forte et faible stabilité est fixée par un seuil. Cet algorithme ne nécessite pas une connaissance globale du réseau, mais utilise des données locales. Les résultats sont validés en étudiant le temps au bout duquel plus de nœuds reçoivent l'information et en comparant avec d'autres algorithmes de la littérature. Cependant, dans les réseaux réels, les changements de structure ne sont pas dus qu'à la mobilité, mais également à des changements de la densité des nœuds à un moment donné. Pour tenir compte de l'influence de tels événements sur la diffusion des informations concernant la sécurité publique, l'auteur utilise les concepts de modèle de métapopulation, épidémiologiques, “beamforming” et mobilité géographique obtenu à partir de données D4D. L'auteur propose la création de trois états latents qu'il ajoute au modèle épidémiologique connu: SIR. L'auteur étudie les états transitoires en analysant l'évolution du nombre de postes ayant reçu les informations et compare les résultats concernant ce nombre dans les différents cas. L'auteur démontre ainsi que le scenario qu'il propose permet d'améliorer le processus de diffusion des informations. Il montre aussi les effets de différents paramètres comme le nombre de sources, le nombre de paquets, les paramètres de mobilité et ceux qui caractérisent les antennes sur la diffusion des informationsIn public warning message systems, information dissemination across the network is a critical aspect that has to be addressed. Dissemination of warning messages should be such that it reaches as many nodes in the network in a short time. In communication networks those based on device to device interactions, dissemination of the information has lately picked up lot of interest and the need for self organization of the network has been brought up. Self organization leads to local behaviors and interactions that have global effects and helps in addressing scaling issues. The use of self organized features allows autonomous behavior with low memory usage. Some examples of self organization phenomenon that are observed in nature are Lateral Inhibition and Flocking. In order to provide self organized features to communication networks, insights from such naturally occurring phenomenon is used. Achieving small world properties is an attractive way to enhance information dissemination across the network. In small world model rewiring of links in the network is performed by altering the length and the direction of the existing links. In an autonomous wireless environment such organization can be achieved using self organized phenomenon like Lateral inhibition and Flocking and beamforming (a concept in communication). Towards this, we first use Lateral Inhibition, analogy to Flocking behavior and beamforming to show how dissemination of information can be enhanced. Lateral Inhibition is used to create virtual regions in the network. Then using the analogy of Flocking rules, beam properties of the nodes in the regions are set. We then prove that small world properties are achieved using average path length metric. However, the proposed algorithm is applicable to static networks and Flocking and Lateral Inhibition concepts, if used in a mobile scenario, will be highly complex in terms of computation and memory. In a mobile scenario such as human mobility aided networks, the network structure changes frequently. In such conditions dissemination of information is highly impacted as new connections are made and old ones are broken. We thus use stability concept in mobile networks with beamforming to show how information dissemination process can be enhanced. In the algorithm, we first predict the stability of a node in the mobile network using locally available information and then uses it to identify beamforming nodes. In the algorithm, the low stability nodes are allowed to beamform towards the nodes with high stability. The difference between high and low stability nodes is based on threshold value. The algorithm is developed such that it does not require any global knowledge about the network and works using only local information. The results are validated using how quickly more number of nodes receive the information and different state of the art algorithms. We also show the effect of various parameters such as number of sources, number of packets, mobility parameters and antenna parameters etc. on the information dissemination process in the network. In realistic scenarios however, the dynamicity in the network is not only related to mobility. Dynamic conditions also arise due to change in density of nodes at a given time. To address effect of such scenario on the dissemination of information related to public safety in a metapopulation, we use the concepts of epidemic model, beamforming and the countrywide mobility pattern extracted from the D4D dataset. Here, we also propose the addition of three latent states to the existing epidemic model (SIR model). We study the transient states towards the evolution of the number of devices having the information and the difference in the number of devices having the information when compared with different cases to evaluate the results. Through the results we show that enhancements in the dissemination process can be achieved in the addressed scenario
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Barrera, Raymond C. "Command and Control Data dissemination using IP multicast." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA376707.
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Thesis (M.S. in Software Engineering) Naval Postgraduate School, December 1999."December 1999". Thesis advisor(s): Bert Lundy. Includes bibliographical references (p. 75-76). Also available online.
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Gandhi, Bhavin B. "On the coverage of grid information dissemination protocols." Diss., Online access via UMI:, 2005.
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Leong, Man Ngan. "Evaluating the dissemination of official statistics in Macao." Thesis, University of Macau, 2003. http://umaclib3.umac.mo/record=b1636747.
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