Computing in a heterogeneous environment requires an exchange of information among computers which have different ways of representing information. This type of information exchange demands a standard external data representation. One such standard, Abstract Syntax Notation One (ASN.l), is defined by the International Organization for Standardization (ISO) and its transfer syntax, the Basic Encoding Rules (BER). This project presents the design of a C++ class hierarchy modeling the concepts presented in ASN.l and encapsulating the BER encoding rules. The goal of this class hierarchy is to utilize the rich features of object-oriented paradigm to provide a clean and simple interface for OSI presentation layer protocols to application developers and implementors. This report discusses the class hierarchy in detail and shows how the primitive and constructed ASN.l types are defined, encoded and decoded using this hierarchy. / Master of Science

The topic of this thesis is the transfer of information in vehicles using bus systems. The theoretical part is devoted to the description of communication as a means of passing information and to the mode of communication between individual technical systems via communication networks. Furthermore, it summarizes the specifics of selected communication systems. The practical part of the thesis includes an experiment for which the building of a CAN FD bus model was required. For communication purposes, the programming of SPI protocol on the Field Programmable Gate Array (FPGA) was crucial to provide access to the CAN FD controller. The result is a bus receiving and transmitting test and a timing test for reading and writing data.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24529号 / 医博第4971号 / 新制||医||1065(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 浅野 雅秀, 教授 辻川 明孝 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

No / Satellite networks are expected to support multimedia traffic flows, offering high capacity with QoS guarantees. However, system efficiency is often impaired by packet losses due to erasure channel effects. Reconfigurable and adaptive air interfaces are possible solutions to alleviate some of these issues. On the other hand, network coding is a promising technique to improve satellite network performance. This position paper reports on potential applications of network coding to satellite networks. Surveys and preliminary numerical results are provided on network coding applications to different exemplary satellite scenarios. Specifically, the adoption of Random Linear Network Coding (RLNC) is considered in three cases, namely, multicast transmissions, handover for multihomed aircraft mobile terminals, and multipath TCP-based applications. OSI layers on which the implementation of networking coding would potentially yield benefits are also recommended.

No description available.

No description available.

Network coding is a technique used to increase the capacity of a network by combining messages sent over the network. The combined messages could be separated by using sufficient original messages which were used to combine the messages. Network coding can be implemented in different layers of the 051 stack, but to date a complete comparison between different implementations of network coding has not been done. The goal of this dissertation is to implement a wireless node model with network coding in the MAC layer and evaluate the performance characteristics of reference networks that implement the new node model. This will serve as the first step of a greater goal, namely finding the most favourable position in the 051 stack to implement network coding. The characteristics of the different implementations of network coding are presented in this dissertation. Simulations were done in OPNET® to find further attributes concerning the implementation of network coding in the MAC layer. The simulation process used is presented and explained, and the results from the simulations are analysed. Network coding in the simulations was implemented opportunistically. The results show that the more often different nodes send frames to the coding node, the better network coding performs. The work contributes to finding the best layer for implementing network coding for its increased throughput. A benchmark network was created so that network coding could be implemented in all the layers of the 051 stack, and then be compared to each other. An implementation of network coding in the MAC layer was simulated and analyzed. We conclude that, because there are so many different purposes for which networks are used, a single instance of network coding is unlikely to be similarly beneficial to all purposes. There still remains work to find the most favourable position for network coding in the 051 stack for all the different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011

Network coding is a technique used to increase the capacity of a network by combining messages sent over the network. The combined messages could be separated by using sufficient original messages which were used to combine the messages. Network coding can be implemented in different layers of the 051 stack, but to date a complete comparison between different implementations of network coding has not been done. The goal of this dissertation is to implement a wireless node model with network coding in the MAC layer and evaluate the performance characteristics of reference networks that implement the new node model. This will serve as the first step of a greater goal, namely finding the most favourable position in the 051 stack to implement network coding. The characteristics of the different implementations of network coding are presented in this dissertation. Simulations were done in OPNET® to find further attributes concerning the implementation of network coding in the MAC layer. The simulation process used is presented and explained, and the results from the simulations are analysed. Network coding in the simulations was implemented opportunistically. The results show that the more often different nodes send frames to the coding node, the better network coding performs. The work contributes to finding the best layer for implementing network coding for its increased throughput. A benchmark network was created so that network coding could be implemented in all the layers of the 051 stack, and then be compared to each other. An implementation of network coding in the MAC layer was simulated and analyzed. We conclude that, because there are so many different purposes for which networks are used, a single instance of network coding is unlikely to be similarly beneficial to all purposes. There still remains work to find the most favourable position for network coding in the 051 stack for all the different types of network coding. / Thesis (M. Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2011

Submitted by Bruno Monteiro Pires null (brunomonteiropires@gmail.com) on 2017-03-26T17:30:46Z No. of bitstreams: 1 [ExemplarDefinitivo]Dissertacao_BrunoMonteiroPires.pdf: 2266231 bytes, checksum: a2a20d6564dd53026d68385939001d1c (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-29T18:43:55Z (GMT) No. of bitstreams: 1 pires_bm_me_sjrp.pdf: 2266231 bytes, checksum: a2a20d6564dd53026d68385939001d1c (MD5) / Made available in DSpace on 2017-03-29T18:43:55Z (GMT). No. of bitstreams: 1 pires_bm_me_sjrp.pdf: 2266231 bytes, checksum: a2a20d6564dd53026d68385939001d1c (MD5) Previous issue date: 2017-03-03 / Redes de sensores sem fios possibilitam o monitoramento dos mais diversos fenômenos e processos, além de abrir caminho para a criação de uma nova geração de dispositivos inteligentes, dinâmicos e interconectados. A diversidade das aplicações as quais se destinam estes sistemas, no entanto, impõe uma série de restrições de projeto, o que favorece iniciativas de desenvolvimento orientadas à aplicação. Embora esta abordagem leve à criação de soluções eficazes para aplicações específicas, estabelece um padrão de desenvolvimento restrito e desconsidera possibilidades de otimização mais abrangentes. Atualmente existem iniciativas de padronização bastante ativas para esta categoria de sistemas, como é o caso do IEEE 802.15.4, no entanto ainda restam questões não resolvidas, comuns à maioria das redes de sensores sem fios, como é o caso da instabilidade inerente aos links de rádio de baixa potência. Este trabalho tem como objetivo utilizar mecanismos disponibilizados por padrões bem estabelecidos como o IEEE 802.15.4 para mitigar os problemas de instabilidade relacionados aos links de comunicação nas redes de sensores sem fios, criando uma plataforma de desenvolvimento robusta e versátil, alinhada com os esforços de padronização que se encontram em andamento. Este trabalho apresenta uma proposta para a arquitetura de nodos de sensores sem fios, a qual busca complementar o modelo genérico comumente utilizado, através da adição de suporte à diversidade de interfaces. Também é introduzida uma proposta de extensão para a camada MAC do padrão IEEE 802.15.4, capaz de abstrair as particularidades relacionadas à transmissão de dados em nodos dotados de múltiplas interfaces de comunicação. A fim de validar as propostas realizadas, são descritos e executados experimentos utilizando protótipos reais, construídos com base na arquitetura sugerida anteriormente. Os resultados obtidos demonstram que a grande variedade de interfaces disponibilizada pelo IEEE 802.15.4 é suficiente para implementação de sistemas de comunicação robustos, baseados na técnica de diversidade de interfaces. Também conclui-se que as camadas inferiores da pilha de protocolos são capazes de fornecer informações suficientes para que se possa prever com precisão razoável a qualidade dos links de comunicação. Por fim constata-se, que através da utilização de algoritmos de estimativa de qualidade dos links, em conjunto com técnicas de diversidade de interfaces, pode-se obter links de comunicação mais robustos, com baixo overhead energético. / Wireless Sensor Networks enable the monitoring of various process and fenomena, also leading the way to the creation of a new generation of smart, dynamic and interconected devices. The great diversity of applications to which these systems are intended for, however, put several constraints on it’s projects, motivating the use of application oriented solutions. Although this approach might lead to effective solutions for targeted applications, it also ignores wider optimization possibilities. Currently there are some very active ongoing standardization efforts related to low-power wireless sensor networks, like the IEEE 802.15.4 standard, however there are still unresolved issues, common to the vast majority of these systems like, for example, the inherent unstability of low power wireless comunication links. This paper’s main goal is to provide solutions to mitigate link stability issues related to most of the common wireless sensor network’s radio communication systems. By utilizing mechanisms provided by well established standards, like IEEE 802.15.4, a robust and flexible development platform, aligned with the ongoing standardization processes, will be created. This paper proposes a wireless sensor node architecture that intends to complement most common generic models by adding suport to interface diversity. It also proposes an amendment to IEEE 802.15.4 MAC layer, by adding the capabilities needed to handle interface diversity specifics. In order to validate the previously made proposals, prototipes based on the sugested architecture were built and real-life experiments were conducted. The results indicate firstly that the great number of interfaces supported by IEEE 802.15.4 is enough to allow for the use of frequency based interface diversity technics. It is also possible to conclude that the lower layers of the protocol stack are able to provide enough information to predict link quality with reasonable accuracy. Finally we conclude that through the use link quality estimation algorithms in conjunction with interface diversity techniques it is possible to attain more robust communication links, without incurring in great power consumption overhead.

Pas de résumé en français / We live in the information age. Data has become an essential asset for most everyday situations and business interactions. The need to share data, to generate information, and create new knowledge from that data is common to all fields of research and all economic activity. Managing data is a critical, and sometimes costly, process. When not properly defined, data might become incomplete, inconsistent or, even worse, unusable. Requirements for data evolve and we must define new data or update existing data over the entire data lifecycle. Evolving data requirements is an important issue and a technological challenge as it is not possible to define, in advance, information structures that meet requirements you do not yet know. Specifying information requirements is particularly challenging in domains such as manufacturing where information exchange involves many actors and sharing across multiple functions and software applications. As a result, it becomes hard to find a common information structure for representing data. The challenge is even bigger when a temporal aspect has to be considered since it requires the ability to extend the information structure dynamically over time. One area within the manufacturing domain that we have identified with these characteristics is Product Lifecycle Management (PLM). PLM involves many global actors using a myriad of software applications that perform a series of product management functions that can last from weeks to decades. Because the mechanism to extend models is static by its nature, requiring numerous updates of the initial information model, this operation is expensive in cost and time, and requires and understanding of the entire initial model to ensure correct extensions are developed. This research presents an alternative based on dynamic customization of information models in the context of PLM, by leveraging existing PLM standards and frameworks, and using emerging semantic web technologies such as OWL, SPARQL and SPIN. Following a state of the art in Chapter 2, Chapter 3 defines technical requirements used to evaluate existing PLM standards and frameworks. Based on the analysis of this evaluation, Chapter 4 presents new framework components for defining dynamically customizable information models for PLM. In chapter 5 these components are integrated together into a framework, and a use case demonstrates the efficiency of the framework. Chapter 6 concludes the research and introduces ideas for future research.