Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (p. 66-68)

Thesis ( M.E.E.)--University of Delaware, 2005. / Principal faculty advisor: Stephan Bohacek, Dept. of Electrical & Computer Engineering. Includes bibliographical references.

Thesis (Ph. D.)--Washington State University, August 2007. / Includes bibliographical references (p. 89-97).

A complex adaptive systems approach has been permeating organizational studies and the field of supply network management helping to describe and explain supply network dynamics and emergent inter-firm structures. This has improved our theoretical knowledge of the nature of supply networks transforming raw materials into products, within a constantly changing environment. From the early days of simple structures, describing bi-lateral, local arrangements between firms for the creation of relatively simple products, we are now in an environment of various supply network archetypes, describing different global sourcing regimes of highly integrated, sophisticated products within multi-tier networks. This thesis is a study of the coevolution of the firm and supply network in the commercial aerospace manufacturing sector producing jetliners of 100 or more seats. One of the contributions of this research is to demonstrate how the holistic approach of complexity science can be applied to describe, understand and gain new insight into the coevolution of the firm and the supply network. Based on the findings of multiple interviews and questionnaires in eight global aerospace firms across multiple supply chain tiers, this research finds high-performing clusters of inter-firm characteristics, plus the aspects of structure and integration which deliver the supply network performance. Practitioners can use these specific results to examine their own firms and the new coevolutionary conceptual framework developed in the thesis may aid future research studies of complex adaptive systems in practice. The simple survey design and analysis method used in the final research stage of this research, has the potential for use in other industries, markets and other complex adaptive systems generally to examine performance outcomes and the effects of having or adopting new inter-firm characteristics. Finally, implications for policy include the potential to legitimize supply networks in order to stimulate competition and innovation in the economy.

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Made available in DSpace on 2014-06-12T15:48:27Z (GMT). No. of bitstreams: 2 arquivo1249_1.pdf: 1963665 bytes, checksum: 4d41d19894034bb41cfe58785e1d816a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Usuários de aplicações avançadas, tais os de grade computacional, encontram algumas vezes problemas de desempenho de rede que frustram as suas expectativas de realização de atividades. Por isso, a assistência para comunidades de usuários que tem dificuldades em usar a rede tem sido identificada como uma das principais questões de suporte relacionadas ao desempenho. Isso explica a crescente demanda por serviços de monitoramento que tentam auxiliar os usuários no entendimento das propriedades de rede, bem como no uso de suas aplicações. Serviços de monitoramento trouxeram grandes benefícios em termos de suporte aos usuários. Mesmo assim, existe uma carência por serviços de aconselhamento que beneficie os usuários com informações que vão além da simples apresentação das propriedades de rede. Atualmente, tanto usuários avançados quanto equipes de suporte contam com ferramentas que apresentam informações de uma perspectiva puramente técnica. A maioria delas se baseiam em informações obtidas como resultado de atividades de monitoramento, independentemente dos níveis de qualidade de serviços percebidos pelos usuários. Tais ferramentas de medição atendem razoavelmente os requisitos dos gerentes, operadores e usuários finais quando se trata de aplicações comuns. Contudo, a comunidade de pesquisa vem destacando a importância da qualidade de experiência (QoE) durante a avaliação dos serviços de rede quando se trata de aplicações avançadas. Ao considerar as opiniões dos usuários, o gerenciamento da qualidade de serviços torna-se mais efetivo, uma vez que a avaliação do serviço não está restrita às considerações da equipe de suporte e gerenciamento. Essa tese apresenta uma abordagem de aconselhamento para o suporte de usuários de rede que foca na colaboração entre usuários através do compartilhamento das suas experiências no uso das aplicações para construir uma base de conhecimento. O conhecimento representado inclui não somente a informação sobre os problemas de desempenho, como também as características as aplicações e as opiniões dos usuários. Através dessas características, a abordagem procura alcançar altos níveis de satisfação dos usuários pela redução gradual do volume de informações de suporte erradas. Para avaliar a viabilidade dessa abordagem, um modelo de sistema de raciocínio baseado em casos (RBC) foi construído e validado através de um estudo experimental conduzido em laboratório por meio de um sistema multiagente. O sistema é apoiado por uma base de conhecimento baseada no uso de ontologias e um esquema de reputação baseado no algoritmo Pagerank. Os resultados do estudo mostraram a efetividade da abordagem proposta, sua resilência à comportamento de usuários incoerentes e em conluio, e a importância do conhecimento do domínio sobre as atividades de suporte a usuários

M.Ing. (Electrical And Electronic Engineering) / This dissertation presents a fully integrated image rejection receiver, the design of a wireless local area network receiver, by using CMOS transistors, including circuit implementations, as well as the design of a low noise amplifier, down conversion mixer, LC oscillators passive on-chip inductor, IF mixer, and low-pass filter based on CMOS active inductor. The study compares receiver topologies, heterodyne architecture, image rejection and associated problems, direct conversion, low- IF and wideband IF architecture, and DC offset, and presents the chosen circuit configurations for a 2.4 GHz CMOS wireless-LAN receiver. It also compares different topologies of a low noise amplifier, mixers, and oscillators. On-chip passive devices are also presented. The fully integrated image rejection receiver consists of a first stage LNA with input 2.4 GHz and NF equal to 2 dB , output of the LNA signal at 2.4 GHz, with a gain of 24 dB mixing with LC Local oscillator signal 1.2 GHz in the RF Mixer, and the out-mixing signal mixed again with the quadrature Oscillator 1.2 GHz in the IF Mixer. The final stage presents a differential low-pass filter based on a CMOS active inductor 100 MHz. This receiver design operates in the 2.4 GHz frequency. The ultimate aim of this project is to design a small-area IC chip and a low-power fullyintegrated 2.4 GHz CMOS receiver. CMOS was selected as the technology of choice because of its cost advantages in comparison with other processes.

The performance measurement of a service provider network is an important activity. It is required for the smooth operation of the network as well as for reporting and planning. SANReN is a service provider tasked with serving the research and education network of South Africa. It currently has no structure or process for determining network performance metrics to measure the performance of its network. The objective of this study is to determine, through a process or structure, which metrics are best suited to the SANReN environment. This study is conducted in 3 phases in order to discover and verify the solution to this problem. The phases are "Contextualisation", "Design",and "Verification". The "Contextualisation" phase includes the literature review. This provides the context for the problem area but also serves as a search function for the solution. This study adopts the design science research paradigm which requires the creation of an artefact. The "Design" phase involves the creation of the conceptual network performance measurement model. This is the artefact and a generalised model for determining the network performance metrics for an NREN. To prove the utility of the model it is implemented in the SANReN environment. This is done in the "Verification" phase. The network performance measurement model proposes a process to determine network performance metrics. This process includes getting NREN requirements and goals, defining the NRENs network design goals through these requirements, define network performance metrics from these goals, evaluating the NRENs monitoring capability, and measuring what is possible. This model provides a starting point for NRENs to determine network performance metrics tailored to its environment. This is done in the SANReN environment as a proof of concept. The utility of the model is shown through the implementation in the SANReN environment thus it can be said that it is generic.The tools that monitor the performance of the SANReN network are used to retrieve network performance data from. Through understanding the requirements, determining network design goals and performance metrics, and determining the gap the retrieving of results took place. These results are analysed and finally aggregated to provide information that feeds into SANReN reporting and planning processes. A template is provided to do the aggregation of metric results. This template provides the structure to enable metrics results aggregation but leaves the categories or labels for the reporting and planning sections blank. These categories are specific to each NREN. At this point SANReN has the aggregated information to use for planning and reporting. The model is verified and thus the study’s main research objective is satisfied.

Mobile networks are in the process of becoming the world’s leading medium for data traffic. This challenge has raised the bar for Quality of Services (QoS) provided by the mobile network operators. It requires methods and tools to verify the Service Level Agreement (SLA) and benchmark competitors by comparing metrics of QoS, e.g. the round-trip time and available bandwidth. For this purpose, Blixt™ has been developed, which is a property of InfoVista Sweden AB. Blixt™ is an Android application which measures the available bandwidth and the round-trip time for the latest generation of mobile networks. Blixt™ approach relies on a time-stamping protocol commonly known as Two-Way Active Measurement Protocol (TWAMP). This research work discusses how the packet probing parameters affect the accuracy of measurements and the level of intrusiveness. The performance of the technique was experimentally tested and compared to other tools and methods, namely, iPerf3, nPerf and FTP test.

Internet users may not get the service quality promised by theirproviders, and also may not know what service they can receive.When users experience poor Internet connection performance, itis not easy to identify the source of the problem. We developCheesePi, a distributed measurement system that measures theInternet connection experience of home users based on some net-work performance attributes (e.g. latency, packet loss rate, andWiFi signal quality). The CheesePi runs on a Raspberry Pi (acredit card sized computer) connected to the user’s home networkas a measurement agent. It is important to measure the networkperformance from the user’s side since it is difficult to measureeach individual’s link from the operator (provider) side. Eachmeasurement agent conducts measurement periodically withoutdisturbing the user’s Internet quality. Measurements are con-ducted during popular media events from SICS (Swedish Insti-tute of Computer Science) and student accommodations. Themeasurement results show customers with an Ethernet connectionexperienced significantly better latency and packet loss comparedto WiFi users. In most of the measurements users at SICS per-ceived better latency and packet loss compared to the users at thestudent accommodation. We also quantify how customers experi-enced lower performance when streaming from websites which donot use CDN technology compared to the websites which do useCDN, particularly during popular media events. / CheesePi