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Filho, João Bosco Ferreira. "Leveraging model-based product lines for systems engineering." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S080/document.
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Actuellement, de nombreuses entreprises ont besoin de construire des versions\variantes légèrement différentes d'un même système. Ces versions partagent des points communs et des différences, le tout pouvant être géré à l'aide d'une approche ligne de produits (SPL). L'objectif principal d'une SPL est d'exploiter la personnalisation de masse, dans laquelle les produits sont réalisés pour répondre aux besoins spécifiques de chaque client. Pour répondre à ce besoin de personnalisation, les systèmes doivent être étendus de manière efficace, ou modifiés, configurés pour être utilisé dans un contexte particulier. Une approche encourageante consiste à connecter l'approche MDE (l'ingénierie dirigée par les modèles) à l'approche SPL – les SPL basées sur les modèles (MSPL). L'espace de conception, l'environnement du système logiciel que l'on construit (i.e., l'ingénierie du domaine) d'une MSPL est extrêmement complexe à gérer pour un ingénieur. Tout d'abord, le nombre possible des produits d'une MSPL est exponentielle au nombre d'éléments ou de décisions exprimé dans le modèle de variabilité. Ensuite, les modèles de produits dérivés doivent être conformes à de nombreuses règles liées au domaine métier mais aussi aux langages de modélisation utilisés. Troisièmement, le modèle de réalisation qui relie un modèle de variabilité et un modèle de base peut être très expressif. En plus, il faut ajouter que les ingénieurs système utilisent différents langages de modélisation dédiés dans le cadre de projets pour la réalisation de systèmes critiques. Nos contributions sont basées sur le fait qu'une solution générique, pour tous les domaines, et qui dérive des modèles corrects n'est pas réaliste, surtout si on prend en considération le contexte des systèmes complexes décrits précédemment. Nous proposons une approche indépendante du domaine pour générer des contre-exemples de MSPLs, révélant des erreurs de conceptions de modèles et supportant les parties prenantes à construire de meilleures MSPLs et des mécanismes de dérivation plus efficaces. Plus précisément, la première et principale contribution de la thèse est un processus systématique et automatisé, basé sur CVL (common variability language), pour la recherche aléatoire de contre-exemples de MSPL dans un langage donné. La seconde contribution de la thèse est un étude sur les mécanismes pour étendre la sémantique des moteurs de dérivation, offrant une approche basée sur des modèles à fin de personnaliser leurs sémantique opérationnelle. Dans la troisième contribution de la thèse, nous présentons une étude empirique à large échelle sur le langage Java en utilisant notre approche générative. La quatrième et dernière contribution de la thèse est une méthodologie pour intégrer notre travail dans une organisation qui cherche à mettre en œuvre les lignes de produit logiciels basées sur des modèles pour l'ingénierie des systèmesSystems Engineering is a complex and expensive activity in several kinds of companies, it imposes stakeholders to deal with massive pieces of software and their integration with several hardware components. To ease the development of such systems, engineers adopt a divide and conquer approach : each concern of the system is engineered separately, with several domain specific languages (DSL) and stakeholders. The current practice for making DSLs is to rely on the Model-driven Engineering (MDE. On the other hand, systems engineering companies also need to construct slightly different versions/variants of a same system; these variants share commonalities and variabilities that can be managed using a Software Product Line (SPL) approach. A promising approach is to ally MDE with SPL – Model-based SPLs (MSPL) – in a way that the products of the SPL are expressed as models conforming to a metamodel and well-formedness rules. The Common Variability Language (CVL) has recently emerged as an effort to standardize and promote MSPLs. Engineering an MSPL is extremely complex to an engineer: the number of possible products is exponential; the derived product models have to conform to numerous well- formedness and business rules; and the realization model that connects a variability model and a set of design models can be very expressive specially in the case of CVL. Managing variability models and design models is a non-trivial activity. Connecting both parts and therefore managing all the models is a daunting and error-prone task. Added to these challenges, we have the multiple different modeling languages of systems engineering. Each time a new modeling language is used for developing an MSPL, the realization layer should be revised accordingly. The objective of this thesis is to assist the engineering of MSPLs in the systems engineering field, considering the need to support it as earlier as possible and without compromising the existing development process. To achieve this, we provide a systematic and automated process, based on CVL, to randomly search the space of MSPLs for a given language, generating counterexamples that can server as antipatterns. We then provide ways to specialize CVL’s realization layer (and derivation engine) based on the knowledge acquired from the counterexamples. We validate our approach with four modeling languages, being one acquired from industry; the approach generates counterexamples efficiently, and we could make initial progress to increase the safety of the MSPL mechanisms for those languages, by implementing antipattern detection rules. Besides, we also analyse big Java programs, assessing the adequacy of CVL to deal with complex languages; it is also a first step to assess qualitatively the counterexamples. Finally, we provide a methodology to define the processes and roles to leverage MSPL engineering in an organization
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Wang, Yi. "Superconducting coplanar delay lines." Thesis, University of Birmingham, 2005. http://etheses.bham.ac.uk//id/eprint/7/.
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Two 25 ns wideband HTS delay lines with a novel double-spiral meander line (DSML) structure are designed, fabricated and measured. One is based on the conventional coplanar waveguide (CPW), and the other based on a conductor-backed coplanar waveguide (CBCPW). Systematic design work is presented in this thesis on the calculations of transmission-line parameters, the selection and optimisation of delay line patterns, and the modelling of the transitions and connections at the input/output. Simulations show that the DSML structure has better transmission efficiency over a wide frequency range than the conventional double-spiral line (DSL). The bandwidth and dispersion of such a meander structure are investigated. The fabricated delay lines are first characterised as resonators with a fundamental mode at ~20 MHz. The surface resistances of the superconductors and the temperature- and power-dependent properties are investigated by measuring the Q-values of more than 1000 harmonics from 20 MHz to 20 GHz. Then, the delay lines are fully connected as they would be used in the application and measured thoroughly in both the frequency and time domain. The performance of the CBCPW delay line is the best ever demonstrated in terms of the widest resonance-free band (2 to 18 GHz), low insertion loss (0.06 dB/ns at 60 K and 10 GHz), small ripple (<1 dB up until 16 GHz), and small dispersion (< 2 ns in the variation of group delay between 2 and 18 GHz). This is the first coplanar delay line successfully demonstrated without using bonding-wires to join the in-plane grounds. The spurious reflecting elements in the DSML structure are identified by the time domain analyses. The results from this measurement are compared comprehensively with those from both resonance measurement and simulations.
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Simpson, John P. "Radiation from microstrip transmission lines." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5435.
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Cargill, James. "Multitone signalling on telephone lines." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5543.
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Ferreira, Santana Neiva Danuza. "RIPLE-RE: A requeriments engineering process for software product lines." Universidade Federal de Pernambuco, 2009. https://repositorio.ufpe.br/handle/123456789/2259.
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Previous issue date: 2009Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco
Linhas de Produto de Software é uma importante estratégia de reuso para minimizar custos e tempo de entrega das aplicações, e maximizar a qualidade e produtividade do desenvolvimento de software. Entretanto, isso envolve o gerenciamento dos pontos comuns e variáveis entre diferentes aplicações, que aumenta sua complexidade quando comparado com desenvolvimento de software tradicional. Assim, desenvolver uma Linha de Produto requer tempo e planejamento para apresentar resultados positivos, ao contrário, o investimento pode ser perdido devido a falhas no projeto. Nesse contexto, um processo de Engenharia de Requisitos é importante para reduzir os riscos envolvidos em uma Linha de Produto, fornecendo gerenciamento e desenvolvimento de requisitos corretos. Por outro lado, existe um desafio chave em Engenharia de Requisitos para Linhas de Produto, que envolve uma solução adequada para gerenciar variabilidades, integrando-as e relacionado decisões em diferentes artefatos para facilitar a derivação de produtos. Assim, o desenvolvimento de Linhas de Produto deve ser apoiado por um processo de Engenharia de Requisitos adequado para o seu contexto. Atualmente, existem muitas abordagens de Engenharia de Requisitos para Linhas de Produto, entretanto, elas apresentam alguns problemas, tais como a ausência de um processo completo e sistemático, com detalhes suficientes para o ciclo de vida da Engenharia de Requisitos. Assim, este trabalho define um processo sistemático de Engenharia de Requisitos, descrevendo atividades, tarefas, entradas, saídas, papéis e guidelines para o contexto de Linhas de Produto, em uma forma usável, efetiva e eficiente. Por fim, um estudo experimental é apresentado para identificar a viabilidade do processo proposto
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Jamali, Sadegh. "Accurate fault location for power transmission lines." Thesis, City, University of London, 1990. http://openaccess.city.ac.uk/17425/.
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This thesis describes a new accurate fault location technique for power transmission lines. The technique is based on a distributed parameter line model which inherently accounts for line conductor asymmetry and shunt capacitance. The accuracy of the new technique is not significantly affected by fault resistance, source network configuration or line length. Also, in most cases no fault type identification is required. The new fault location technique uses the current and voltage phasors at power frequency measured at the line ends. These measurements are synchronised from a knowledge of the prefault phasor data. For a single-phase network the basic idea is to equate two equations obtained for the fault point voltage; one from the sending end phasor data and the other from the receiving end phasor data. The resultant equation is solved for the distance to fault. For multiphase systems the idea is 'generalised by using the theory of natural modes which involves the evaluation of eigenvalues and eigenvectors of the lines. In this way a multiphase system is decoupled into a number of single-phase modal circuits; each circuit can be solved for fault location. For perfectly transposed lines the eigenvalues can simply be evaluated from the sequence components and a real eigenvector matrix can be defined for all the lines. For untransposed lines the new algorithm maintains its high accuracy when assuming perfect transposition to simplify the evaluation of eigenvalues and eigenvectors. Also for double-circuit applications a circuit-by-circuit fault location, without any link between the two circuits, is possible. The test results for different fault conditions presented in this thesis show the higher accuracy in fault location achieved by the new,algorithm in comparison with the algorithms used in the best commercially available fault locators.
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Sousa, André Luís Sequeira de. "Traceability support in software product lines." Master's thesis, FCT - UNL, 2008. http://hdl.handle.net/10362/1798.
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Informática.Traceability is becoming a necessary quality of any modern software system. The complexity in modern systems is such that, if we cannot rely on good techniques and tools it becomes an unsustainable burden, where software artifacts can hardly be linked to their initial requirements. Modern software systems are composed by a many artifacts (models, code, etc.). Any change in one of them may have repercussions on many components. The assessment of this impact usually comes at a high cost and is highly error-prone. This complexity inherent to software development increases when it comes to Software Product Line Engineering. Traceability aims to respond to this challenge, by linking all the software artifacts that are used, in order to reason about how they influence each others. We propose to specify, design and implement an extensible Traceability Framework that will allow developers to provide traceability for a product line, or the possibility to extend it for other development scenarios. This MSc thesis work is to develop an extensible framework, using Model-Driven techniques and technologies, to provide traceability support for product lines. We also wish to provide basic and advanced traceability queries, and traceability views designed for the needs of each user.
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Sa, Yingshi 1965. "Reliability analysis of electric distribution lines." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29546.
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Wood Poles are extensively used in North America as supports for electric distribution lines. On average, wood poles have a service life of 40 years with a replacement cost of approximately $2000. Since the distribution network is of relatively recent construction, maintenance and replacement costs have been relatively small compared to the total number of poles in service.The goal of this thesis is to use the FORM/SORM algorithm to evaluate the reliability of a single pole and the results obtained when applied to a sample of 887 wood poles inspected in the field. The procedure was also applied to a sample of poles designed according to the current codes in order to calibrate the evaluation procedure. The results indicate that the proposed procedure will improve the current maintenance and replacement strategy by guarantying a more uniform level of reliability throughout the network and by decreasing by up to 33% the number of wood pole replacements. (Abstract shortened by UMI.)
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Tcheou, Genevieve. "Non-linear dynamics of mooring lines." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10524.
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Méndez, Acuña David Fernando. "Leveraging software product lines engineering in the construction of domain specific languages." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S136/document.
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La complexité croissante des systèmes logiciels modernes a motivé la nécessité d'élever le niveau d'abstraction dans leur conception et mis en œuvre. L'usage des langages dédiés a émergé pour répondre à cette nécessité. Un langage dédié permet de spécifier un système logiciel à travers des concepts relatifs au domaine d'application. Cette approche a plusieurs avantages tels que la diminution des détails techniques auxquels les développeurs doivent faire face, la séparation des préoccupations et la participation des experts du domaine dans le processus de développement. Malgré les avantages fournis par l'usage des langages dédiés, cette approche présente des inconvénients qui remettent en question sa pertinence dans des projets réels de développement logiciel. L'un de ces inconvénients est le coût de la construction des langages dédiés. La définition et l'outillage de ces langages est une tâche complexe qui prend du temps et qui requiert des compétences techniques spécialisées. Le processus de développement des langages dédiés devient encore plus complexe lorsque nous prenons en compte le fait que ces langages peuvent avoir plusieurs dialectes. Dans ce contexte, un dialecte est une variante d'un langage qui introduit des différences au niveau de la syntaxe et/ou de la sémantique. Afin de réduire le coût du processus de développement des langages dédiés, les concepteurs des langages doivent réutiliser autant de définitions que possible pendant la construction des variantes. Le but est d'exploiter les définitions et l'outillage définis précédemment pour dunaire au maximum, la mis en ouvre des zéro dans la construction de langages. Afin de répondre à la question de recherche précédemment énoncée, la communauté de recherche autour de l'ingénierie des langages a proposé l'usage des lignes de produits. En conséquence, la notion de lignes de langages a récemment émergé. Une ligne de langages est une ligne de produis où les produits sont des langages. Le principal but dans les lignes de langages est la définition indépendante de morceaux de langage. Ces morceaux peuvent être combinées de manières différentes pour configurer des langages adaptés aux situations spécifiques. D'une manière similaire aux lignes de produits, les lignes de langages peuvent être construites à partir de deux approches différentes: top-down et bottom-up . Dans l'approche top-down, les lignes de langages sont conçues et mis en œuvre au travers d'un processus d'analyse du domaine où les connaissances du domaine sont utilisées pour définir un ensemble de modules de langage qui réalisent les caractéristiques de la ligne de langages. En outre, les connaissances du domaine sont aussi utilisées pour représenter la variabilité de la ligne de langages à travers des modèles bien structurés qui, en plus, servent à configurer des langages particuliers. Dans l'approche bottom-up, les lignes des langages sont construites à partir d'un ensemble de variantes des langages existant au travers de techniques d'ingénierie inverse. À partir des approches précédemment énoncées, nous proposons deux contributions : (1) Des facilités pour supporter l'approche top-down. Nous proposons une approche de modularisation des langages qui permet la décomposition des langages dédiés comme modules de langages interdépendants. En plus, nous introduisons une stratégie de modélisation pour représenter la variabilité dans une ligne de langages. (2) Techniques d'ingénierie inverse pour supporter l'approche bottom-up. Comme deuxième contribution, nous proposons une technique d'ingénierie inverse pour construire, de manière automatique, une ligne de langages à partir d'un ensemble de variantes de langages existantes. Nos contributions sont validées à travers des cas d'étude industrielsThe use of domain-specific languages (DSLs) has become a successful technique in the development of complex systems because it furnishes benefits such as abstraction, separation of concerns, and improvement of productivity. Nowadays, we can find a large variety of DSLs providing support in various domains. However, the construction of these languages is an expensive task. Language designers are intended to invest an important amount of time and effort in the definition of formal specifications and tooling for the DSLs that tackle the requirements of their companies. The construction of DSLs becomes even more challenging in multi-domain companies that provide several products. In this context, DSLs should be often adapted to diverse application scenarios, so language development projects address the construction of several variants of the same DSL. At this point, language designers face the challenge of building all the required variants by reusing, as much as possible, the commonalities existing among them. The objective is to leverage previous engineering efforts to minimize implementation from scratch. As an alternative to deal with such a challenge, recent research in software language engineering has proposed the use of product line engineering techniques to facilitate the construction of DSL variants. This led the notion of language product lines i.e., software product lines where the products are languages. Similarly to software product lines, language product lines can be built through two different approaches: top-down and bottom-up. In the top-down approach, a language product line is designed and implemented through a domain analysis process. In the bottom-up approach, the language product line is built up from a set of existing DSL variants through reverse-engineering techniques. In this thesis, we provide support for the construction of language product lines according to the two approaches mentioned before. On one hand, we propose facilities in terms of language modularization and variability management to support the top-down approach. Those facilities are accompanied with methodological insights intended to guide the domain analysis process. On the other hand, we introduce a reverse-engineering technique to support the bottom-up approach. This technique includes a mechanism to automatically recover a language modular design for the language product line as we as a strategy to synthesize a variability model that can be later used to configure concrete DSL variants. The ideas presented in this thesis are implemented in a well-engineered language workbench. This implementation facilitates the validation of our contributions in three case studies. The first case study is dedicated to validate our languages modularization approach that, as we will explain later in this document, is the backbone of any approach supporting language product lines. The second and third case studies are intended to validate our contributions on top-down and bottom-up language product lines respectively
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Liu, Qing. "Antennas using left handed transmission lines." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/595/.
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The research described in this thesis is concerned with the analysis and design of conventional wire antenna types, dipoles and loops, based on the left-handed transmission line approach. The left handed antennas have a unique feature that the wavelength of the induced current becomes shorter with decreasing frequency. The left handed transmission line concept can be extended to construct reduced-size dipole or loop antennas in the VHF frequency band. The use of higher order modes allows orthogonal polarisation to be obtained, which is thought to be a feature unique to these antennas. Efficiency is a key parameter of left handed antennas as the heavy left handed loading increases the resistive loss. A study of the efficiency of small dipole antennas loaded with a left-handed transmission line is specially described, and the comparison with conventional inductive loading dipoles. In a low order mode, the efficiency of L-loading dipole is better with low number of unit cell. If the number of cell increases, CL-loading presents comparable and even better performance. In a high mode the meandered left handed dipole gives the best efficiency due to the phase distribution, presenting orthogonal polarization as well. The optimized dipole loaded with parallel plate capacitors and spiral inductors presents the best performance in impedance and efficiency, even better than the conventional inductive loading. A planar loop antenna using a ladder network of left handed loading is also presented. Various modes can be obtained in the left handed loop antenna. The zero order mode gives rise to omnidirectional patterns in the plane of the loop, with good efficiency. By loading the loop with active components, varactors, a tunable left handed loop antenna with a switchable radiation pattern is implemented. The loop gives an omnidirectional pattern with a null to z axis while working in an n = 0 mode and can switch to a pattern with a null at phi = 45° in the plane of the loop in an n = 2 mode.
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Hart, Alan William. "Engineering non-neuroendocrine cell lines to constitutively secrete fully processed insulin." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265894.
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Gene therapy, where non-islet cells are transduced to express insulin, encapsulated and implanted into the diabetic patient, is a possible alternative therapy for type I diabetes, which may alleviate some of the long-term complications of the disease. Insulin, however, is synthesised as a precursor, proinsulin, which is proteolytically modified by two endocrine-cell specific proteases, PC2 and PC3. Non-neuroendocrine cells do not express PC2 and PC3, but express a related protease, furin. Furin is unable to process proinsulin to insulin efficiently, so we employed PCR mutagenesis to alter the human preproinsulin cDNA around the normal processing sites, which when transcribed and translated yield cleavage sites recognised by furin. Wild type and mutant preproinsulin cDNAs were cloned into a mammalian expression vector under the control of the CMV promoter, and were expressed in the C2C12 and L6 myoblast cell lines and also the HepG2 liver cell line. Radioimmunoassays using an insulin specific antibody and an antibody that recognises proinsulin and insulin equally revealed that cells transfected with the wild type cDNA secreted 90% proinsulin whereas cells expressing the mutant cDNA secreted 75-90% processed insulin, suggesting more efficient processing of the mutant proinsulin by the endogenous furin. Further manipulation of the cDNAs linking them to the neomycin selection gene via an internal ribosome entry sequence (IRES), gave rise to stably transfected L6ins cell lines, expressing 2-10 ng/ml/24h total insulin-like immunoreactivity (ILI). With stable HepG2ins cells expressing in excess of 2.5 μg/5x107 cells/24h mature, biologically active human insulin. These high expressing HepG2ins cells were implanted into BB/Edinburgh rates and strepozotocin treated nude mice.
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Matarrese, Vincent D. "Tapered radio frequency transmission lines." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4329.
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A transformation used to obtain solutions for the beam parameter equation of fiber optics is applied to the second order differential equation for nonuniform transmission lines. Methods are developed for deriving possible transmission line tapers from known solutions of the transformed equation. This study begins with a comprehensive overview of previous work done to obtain closed-form solutions for the transmission line equations. Limitations of the lumped parameter model are also discussed. As part of this thesis, a tapered transmission line is constructed, based on one of the solutions obtained from the fiber optics studies. A discussion of the design and measurement results are given in the final chapter.
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Yang, Zemo 1957. "A study of lossy transmission lines." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/292035.
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Under the assumption of quasi-transverse electric and magnetic (quasi-TEM) mode of propagation, the transmission characteristics of a thin film microstrip line have been studied. Several numerical programs were employed to calculate the frequency dependent electrical parameters of the microstrip line, and to carry out the transient simulation in the thesis. Based on the simulation results, the relations of pulse distortion to the signal frequency content and the length of line have been investigated. Several transmission characteristics, such as attenuation and dispersion have been paid more attention, and their dependences on the frequency dependent electrical parameters have also been studied. Furthermore, a designing rule for the geometry of thin film microstrip lines is drawn, and a general conclusion is made concerning the effect of conductor losses on thin film microstrip line parameter and the things which should be considered in the design.
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Thomas, David William Phillip. "Protection of major transmission lines using travelling-waves." Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/14111/.
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An ultra high speed relay for the protection of long EBY transmission lines is described in this thesis. The need for ultra high speed relays is first discussed. From a brief review of protection based on "impedance" distance algorithms or methods using post fault transients, it is shown that at present, there is no truly ultra high speed relay available for the protection of long EBY transmission lines. The proposed relay operates on the incident fault transient travelling waves received at the relaying point only. After the arrival of the first incident transient at the relaying point all subsequent incident travelling waves are detected using the cross-correlation of the first reflected wave with the incident transient waves. From the amplitudes of the subsequent incident transients, two fault resistance estimates are obtained. These two fault resistance estimates are in agreement only for the subsequent incident wave which is caused by direct reflection from the fault. The fault location can then be determined from the time of arrival of this wave. Additional checks based on the ground mode delay or the line round trip wave amplitude, are incorporated to enhance further the security of the scheme. Good fault discrimination is shown to be possible over a large range of fault resistances for symmetric three phase faults to ground, phase to ground faults and phase to phase faults. Double circuit transmission lines and compensated transmission lines can also be protected. The relay has good noise tolerance and a reasonable bandwidth requirement. A real time implementation of the basic algorithm for an internal phase-a to ground fault shows that an ultra high speed relay response with good accuracy can be achieved using currently available digital hardware.
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Almajali, Ziyad. "Fault diagnosis for transmission lines using chromatic processing." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2019779/.
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Diagnosing the type of fault and its location in a transmission lines is performed by a variety of techniques and mainly relies on monitoring currents and voltages in the transmission line. Accurate fault diagnosis plays an important role in improving the overall system reliability, has a significant effect on the quality of service provided, improves the protection system efficiency, reduces power outage time and limits the risks and the economic losses. Transmission lines extend over wide areas and are exposed to vulnerable situation, to the harsh and uncontrolled environment random events (e.g.~lightning), this can lead to loss of lines due to various faults. This fact has an attraction for researchers to focus on utilising possible methods to improve protection system and supporting fault diagnosis solutions to overcome many of the transient fault conditions. This thesis explores an alternative method of fault diagnosis and location. The approach uses chromatic methodology to extract information from current and voltage waveforms from a simulated transmission line with different fault conditions. These waveforms are processed chromatically. The process involves two steps, filtering which is performed on a cycle by cycle basis of the three symmetrical components for each waveform, and then using the chromatic transformations to represent the outputs in an information space. Various chromatic models are available but the hue, lightness and saturation (HLS) model is employed in this study and the relation between changes in the waveforms and changes in the chromatic parameters forms the foundation for building the proposed diagnosis algorithms. A fault type classifier algorithm for the asymmetrical faults has been proposed for both, double and single line transmission systems. It employs the chromatic H parameter variation with the fault type for the negative sequence component. The processed waveforms are either the voltage or the current at a single terminal of the transmission line. L chromatic parameter values of the zero sequence component are incorporated in the algorithm to add the ground fault distinguishing element and the L parameter values of the rectified negative sequence component were used to support the classification decision even with high fault resistance. Another algorithm for fault location estimation for all types of faults has been used for the double transmission line system. It employs the L chromatic parameter values of the rectified positive sequence component. The processed waveforms are the current collected from both terminals of the transmission line. Finally, the proposed algorithms have been tested by variation of possible conditions of the faults, such as changing the fault location, the fault resistance, the line configurations and parameters, etc. In addition to robustness testing with different fault scenarios. Experimental results taken from a lumped parameter laboratory system have been also used to verify the outputs of the chromatic processing. The performance of the chromatic approach and other reported methods have been compared. The error of the chromatic method compares favourably with others. As such overall performance can be described as being good, this is encouraging and future work through proposing diagnostic tools for other power system components is needed.
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Oliveira, Raphael Pereira de. "Understanding And Guiding Software Product Lines Evolution Based On Requirements Engineering Activities." Instituto de Matemática, 2015. http://repositorio.ufba.br/ri/handle/ri/22846.
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Software Product Line (SPL) has emerged as an important strategy to cope with the increasing demand of large-scale products customization. SPL has provided companies with an efficient and effective means of delivering products with higher quality at a lower cost, when compared to traditional software engineering strategies. However, such benefits do not come for free. There is a necessity in SPL to deal with the evolution of its assets to support changes within the environment and user needs. These changes in SPL are firstly represented by requirements. Thus, SPL should manage the commonality and variability of products by means of a “Requirements Engineering (RE) - change management” process. Hence, besides dealing with the reuse and evolution of requirements in an SPL, the RE for SPL also needs an approach to represent explicitly the commonality and variability information (e.g., through feature models and use cases). To understand the evolution in SPL, this Thesis presents two empirical studies within industrial SPL projects and a systematic mapping study on SPL evolution. The two empirical studies evaluated Lehman’s laws of software evolution in two industrial SPL projects,demonstrating that most of the laws are supported by SPL environments. The systematic mapping study on SPL evolution identified approaches in the area and revealed gaps for researching, such as, that most of the proposed approaches perform the evolution of SPL requirements in an ad-hoc way and were evaluated through feasibility studies. These results led to systematize, through guidelines, the SPL processes by starting with the SPL requirements. Thus, it was proposed an approach to specify SPL requirements called Feature-Driven Requirements Engineering (FeDRE). FeDRE specifies SPL requirements in a systematic way driven by a feature model. To deal with the evolution of FeDRE requirements, a new approach called Feature-Driven Requirements Engineering Evolution (FeDRE2) was presented. FeDRE2 is responsible for guiding, in a systematic way, the SPL evolution based on activities from RE. Both proposed approaches, FeDRE and and FeDRE2, were evaluated and the results, besides being preliminaries, shown that the approaches were perceived as easy to use and also useful, coping with the improvement and systematization of SPL processes.
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Jang, Young Jae 1974. "Mathematical modeling and analysis of flexible production lines." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39841.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.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. 165-[166]).
We present a model and analysis of a production line that processes different part types on unreliable machines which operate according to a priority rule. The production line consists of machines separated by storage areas in which parts flow in a fixed sequence. A machine operates on the highest priority part whenever possible, and only operates on lower priority parts when unable to produce the higher priority parts. Part priorities are static and are a function only of part type. The purpose of this thesis is to present mathematical formulations and algorithms for estimating production rates and average inventory levels for each part type in a flexible production line. The qualitative behavior of the multiple-part-type line under different supply and demand scenarios is described.
by Young Jae Jang.
Ph.D.
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Royce, Christina C. "Simulation of tandem and Re-Entrant manufacturing lines." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36705.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 52).
Modeling manufacturing systems is a necessary tool in the process of finding a way to analyze and improve design. Increasingly complex systems are now being modeled, and two such systems are the focus of this report. The Tandem and Re-Entrant systems allow for multiple part types to be sent through a single line of processing machines. The parts have different priorities which determine the order in which they are produced. The Re-Entrant system is unique because it produces a single part that is processed through the same machine line multiple times. As the part travels through the processing line, it loops back to the beginning at the end of every run as a higher priority part. These simulations were tested for their validity by running with different input parameters to see how the system reacted. These programs can be used in the future with more complex systems and the knowledge gained from the results of these simulations can be applied to improving these systems and maximizing their efficiency.
by Christina C. Royce.
S.B.
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Odia, Osaretin Edwin. "Testing in Software Product Lines." Thesis, Blekinge Tekniska Högskola, Avdelningen för programvarusystem, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3853.
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This thesis presents research aimed at investigating different activities involved in software product lines testing process and possible improvements towards achieving developing high quality software product lines at reduced cost and time. The research was performed using systematic review procedures of Kitchenham. The reviews carried out in this research covers several areas relating to software product lines testing. The reasons for performing a systematic review in this research are to; summarize the existing evidence covering testing in software product line context, to identify gaps in current research and to suggest areas for further research. The contribution of this thesis is research aimed at revealing the different activities, issues and challenges in software product lines testing. The research into the different activities in software product lines lead to the proposed SPLIT Model for software product lines testing. The model helps to clarify the steps and activities involved in the software product line testing process. It provides and easy to follow map for testers and managers in software product line development organizations. The results were mainly on how testing in software product lines can be improved upon, towards achieving software product line goals. The basic contribution is the proposed model for product line testing, investigation into, and possible improvement in, issues related to software product line testing activities.The main purpose of the research as presented in this thesis is to present a clear picture of testing in the context of software product lines, which is quite different from testing in single product. The focus of this thesis is specifically the different steps and activities involved in software product lines testing and possible improvements in software product lines testing activities and issues towards achieving the goals of developing high quality software product lines at reduced cost and time. But, for software product lines to achieve its goals, there should be a comprehensive set of testing activities in software product lines development. The development activities from performing analyses and creating designs to integrating programs in software product line context, component testing and tools support for software product lines testing should be taken into consideration.
0046762913149 eddy_odia2002@yahoo.co.uk
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Ghassemi, Foroozan. "Adaptive digital distance protection for series compensated transmission lines." Thesis, City University London, 1989. http://openaccess.city.ac.uk/8235/.
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Series capacitors offer considerable technical and economical advantages in long distance a.c. transmission. In particular, their excellent reliability and minimal maintenance requirements make series compensation the most cost effective method of enhancing the power transfer capability of an existing or proposed interconnection. E.H.V. lines employing series capacitors however, pose difficult problems for the line protection relays, not encountered with plain feeders. One important cause of these problems is the resonance between the series capacitor and the line series inductance, which in turn imposes a sub-synchronous oscillation on the system signals. Also, the rapid changes in the circuit parameters, resulting from the operation of the capacitor protection equipment, namely the spark gaps, introduce some difficulties for the line protection schemes, especially an impedance measuring relay. These spark gaps are installed in parallel with the series capacitors to prevent the development of very high voltages across the capacitor which could cause excessive damage to the equipment. The work presented herein describes a new digital distance relay suitable for series compensated line applications. The errors in the impedance measurement for a phase to earth fault when the spark gaps do not flash over, are discussed and new methods are proposed to compensate for these errors. The new concept of a complex residual compensation factor, as opposed to a real one, is also discussed. A new adaptive filtering is incorporated in the relay in order to minimise the detrimental effect of the subsynchronous oscillation on the relay decision logic. Finally, the relay is thoroughly tested for many different system configurations, to fully evaluate the relay response.
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Charalampidis, Panagiotis. "Characterisation of textured insulators for overhead lines and substations." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/43818/.
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Pollution flashover constitutes the predominant parameter for the design,specification and dimensioning of high voltage outdoor insulation [1-2]. For over a quarter of a century, polymeric insulators have been used for overhead lines and substations due to their enhanced performance in highly polluted environments. This is mainly attributed to the hydrophobic properties of polymeric surfaces thatlead to a reduction of surface wetting and, thus, to a reduction of leakage current and discharge activity that could result to a flashover. However, under severe ambient conditions, discharge activity is not totally eliminated. The present investigations have demonstrated the development of dry bands and partial arcs on polymeric insulators (Chapter 3). While ‘cap and pin’ ceramic insulators - e.g. porcelain and glass - employ special anti-fog designs of increased leakage path introduced by the presence of deeper ribs, such profiles cannot be used for polymeric insulators due to moulding restrictions [1-1]. Yet, these moulding properties allow the fine texturing of the polymeric surface [1-7]. Textured insulators are a novel approach for the improvement of polymeric insulators using a surface design consisting of an array of hemispherical protuberances of various configurations and range of diameters. The objective is to reduce power dissipation (P = EJ) on the insulator surface by reducing the electric field gradient E and current density J (Chapter 2). Moreover, an increase of the longitudinal creepage path can be achieved without the need of increasing the overall length of the insulator. Where discharges do occur, the formation of parallel current paths could lead to less harmful discharges hence mitigating damage due to thermal stresses. An initial theoretical classification of the textured designs resulted to a shortlist of textured patterns that could be employed for the development of a full insulator prototype. At the next stage, these patterns were experimentally evaluated in a series of material tests in accordance to IEC-60587 inclined-plane test procedure [Chapter 5]. Rectangular silicone rubber samples with a plane surface were tested along with samples with a textured finish to assess the performance against erosion and tracking. The improvement introduced by these textured patterns in comparison with conventional non-textured samples was outstanding [2-48, 49]. The intersecting square pattern showed the best performance, hence it was chosen for the development of a full textured insulator. Conventional 11 kV silicone rubber insulators and textured insulators with the same shed profile were cast in-house using vacuum injection casting techniques. There are no international standards for the artificial testing of polymeric insulators. In this work, a proposed test procedure for non-ceramic insulators is described (Chapter 3). Clean-fog tests of conventional (Chapter 4) and textured insulators (Chapter 6), for a range of wetting and pollution severity conditions,showed that textured insulators showed an improved flashover performance that in some cases reached 26 %. Surface texturing seems to be more effective under severe conditions of wetting and pollution and when hydrophobicity is reduced, like the temporary loss of hydrophobicity observed for silicone rubber insulators in service.
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Olsen, Anders Tuhus. "Voltage Upgrading of Overhead Lines." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11218.
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Statnett wants to increase the transmission capacity in their 300 kV overhead lines by upgrading the operating voltage to 420 kV. To make this possible some modifications must be done. Insulator strings have to be elongated by two to four insulators and the air clearances must be checked. EN standards provide guidelines for how to calculate the air clearances adequately to provide required safety margins.It turns out that the formulas given by the standards provide greater safety margin than appropriate for upgraded transmission lines. By finding new proper safety margins, several towers which otherwise would have to be rebuilt to fulfill the requirements for clearances, can stay unmodified. When considering the number of towers in an average transmission line, there is obviously a great potential for saving money by putting some effort looking into proper minimum air clearances. By reduce the air clearance by approximately 10 cm, 6.5 mill. NOK were spared in a 65 km transmission line. It is therefore desirable to calculate the air clearances on the basis of smaller safety margins than described in the standard, but which is still within acceptable safety limits. In the formulas for minimum distances, the statistical withstand voltage U50%, gap-factors and altitude factors are examined for the cases of operating voltage, switching impulse and lightning impulse.Discrepancies between test results from a laboratory work conducted by STRI and calculations based on the EN standard of U50%, have been discovered. Tested U50 for switching impulses are 59 % higher than U50 from the standard. The same applies for lightning impulses where the tested value is 12 % higher than the standard. This gives reason to assume the standard to be somewhat conservative.Further, discrepancies are found between the standard EN 50341 that says that the gap factor when an insulator is present is the same as if no insulator is present, and Cigré report 72, which says that the gap factor should be corrected for the presence of insulators. Correction for insulators will lead to a lower gap factor i.e. lower break down strength along the insulator string than in the rest of the air gap. It turns out that the combination of rain and insulator string reduce the gap factor and thus, the withstand strength in the cases of switching impulses in the order of 6-13 % for V-string insulators and 20-34 % for I-string insulators and for continuous power frequency voltage in the order of 25 % for V-string insulators and 33-40 % for I-string insulators.Rain has no influence on the withstand strength of I-strings or V-strings exposed to lightning impulses.Several previous researches [1][2] shows the same tendencies of lack of correlation between U50 and gap factors when air gaps with insulator strings are exposed to lightning impulses. Thus, the gap factor is not sufficient to describe the discharge characteristics of air gaps with insulator strings exposed to lightning impulses.It is found that the air gap between phase and guy wire has approximately 7 % greater withstand strength than over the insulator string in a tower window. This additional safety margin is a desirable property in terms that the guy wires are the weakest point of a tower. This should however be verified by full-scale laboratory tests as this is mainly valid for the case of only the conductor-guy wire gap without the presence of the other air gaps that represent the tower window.
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Ghimire, Sushma. "Analysis of Fault location methods on transmission lines." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1800.
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Analysis of different types of fault is an important and complex task in a power system. Accurate fault analysis requires models that determine fault distances in a transmission line. The mathematical models accurately capture behavior of different types of faults and location in a timely manner, and prevents damaging power system from fault energy. The purpose of this thesis is to use two methods for determining fault locations and their distance to the reference end buses connected by the faulted transmission line. The two methods used in this investigation are referred to as impedance-based and traveling wave methods. To analyze both methods, various types of faults were modeled and simulated at various locations on a two-bus transmission system using EMTP program. Application and usefulness of each method is identified and presented in the thesis. It is found that Impedance-based methods are easier and more widely used than traveling-wave methods.
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Qian, Xin. "Optical waveguide analysis using transmission lines." Thesis, Bournemouth University, 2005. http://eprints.bournemouth.ac.uk/452/.
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Optical fibres have been used as a key medium for telecommunication and networking for more than two decades because in principle they offer sufficient transmission capacity, reaching total rates as high as Tbits/s per fibre. Critical fibre properties such as mode field profiles, single-mode propagation conditions and dispersion characteristics can all be related to the optical fibre refractive index profiles. For this reason, it is of fundamental importance to be able to determine the optical fibre refractive index profiles. In this thesis, a novel Transmission-Line technique has been studied and extended for both the forward and inverse solutions. In the forward solution of the Transmission-Line technique, it is shown that the technique is not only capable of determining exactly the propagation constants in optical fibres with real refractive index profiles, but also evaluating accurately the complex propagation constants in single-mode fibres with arbitrary complex refractive index profiles. To illustrate the effectiveness of this technique, it is applied to the evaluation and manipulation of the gain in a typical 980 nm pumped Erbium-Doped fibre as well as to the calculation of the attenuation of optical fibres when radial loss factors are presented. Moreover, based on the Transmission-Line equivalent circuit model, the exact analytical formulas are derived for a recursive algorithm which allows direct and efficient calculation of dispersion of arbitrary refractive index profile optical fibres. The proposed algorithm computes dispersion directly from the propagation constants without the need for curve fitting and successive subsequent numerical differentiation. The algorithm results in savings for both storage memory and computation time. In the inverse solution using the Transmission-Line technique, the optical fibre refractive index profile synthesis from the given mode electric field distribution is developed and demonstrated. The application of the Transmission-Line principles in the study of optical fibre properties was developed for the first time in the early 80's. However, until now the potential of using Transmission-Line technique for the design of optical fibres based on the given electric field pattern had not been examined. From Maxwell's equations, the Transmission-Line equivalent circuits are derived for a homogeneous symmetric optical fibre. This work demonstrates how to use the Transmission-Line model to reconstruct the exact refractive index profile from the electric field data. The accuracy of the reconstructed optical fibre refractive index profile is examined numerically.
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Li, Xiu Hong 1976. "Life cycle cost of support poles in distribution lines." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81551.
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Wood poles are the most common support structures for distribution lines in North America. Wood poles typically have a service life of 40-50 years but may be replaced prematurely when they fail or are damaged by climatic loads or when they have degraded prematurely. The distribution network of Hydro-Quebec comprises more than 2 million wood poles and the selection of an optimal class of poles for new or refurbished lines can potentially represent significant savings. In this project, wood poles from class 1 to 5 and steel poles are considered for new or refurbished lines using life-cycle-cost analysis.The evaluation of life-cycle-costs of a line for a service life of 50 years was performed in two steps. A reliability model was first developed to estimate the probability of failure of single poles with climatic loads. The results of the reliability analysis were then integrated in an economic model that computes the Net Present Value of construction costs and pole replacement costs associated with failure under climatic loads of the whole line. Maintenance costs were neglected in this study since they were determined to be approximately similar for the various classes of poles.
The results indicate that the Class 4 poles that are currently used for the distribution network are not optimal from an economic point of view. For distribution lines located in regions with moderate ice hazard expositions, a Class 2 pole has a 15% cost advantage over the Class 4 poles. For distribution lines located in regions with severe ice hazard expositions, a Class 2 pole has a 30% advantage over the Class 4 poles.
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Kurz, Mary Elizabeth. "Scheduling flexible flow lines with sequence dependent setup times." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290624.
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This dissertation examines scheduling in flexible flow lines with sequence-dependent setup times to minimize makespan. This type of manufacturing environment is found in industries such as printed circuit board and automobile manufacture. Lower makespans can be associated with more efficient use of resources. Poor scheduling when sequence-dependent setup times exist can negatively impact productivity. As a building block, minimizing makespan in parallel identical machines with sequence-dependent setup times is examined. Several heuristics are compared empirically using statistical analysis. Experimental results indicate that a heuristic based on the Insertion Heuristic for the Travelling Salesman Problem is effective. Subsequently, minimizing makespan in flexible flow lines with sequence-dependent setup times is considered. An integer program that incorporates all aspects of the problem is formulated. Due to the NP-hard nature of the problem, heuristic methods are considered. The heuristics, based on greedy methods, flow line methods, the Insertion Heuristic for the Travelling Salesman Problem and genetic algorithms are compared empirically using statistical analysis. The heuristics are designed to take advantage of the flow line nature of the problem, the parallel machine nature and the combinatorial features of the problem. Problem data is generated in order to evaluate the heuristics. The characteristics are chosen to reflect those used by previous researchers. An effective lower bound is created in order to evaluate the heuristics. A random keys genetic algorithm is found to be very effective for the problems eyed. In addition, several extensions based on backwards pass of the schedule and focusing on the bottleneck stage are proposed and examined. These proved to be ineffective approaches but yielded insight regarding what features of schedule are important. Most significantly, the first stage is very important in determining the quality of the subsequent schedule. The heuristics considered here focus on setting a schedule for one stage and then considering the next. Areas for future research include developing methods of scheduling job-by-job and examination of branch and bound methods to find optimal solutions, aided by effective lower bounds and theorems regarding schedule domination.
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Castillo, Joaquin. "Remote control & communication of systems through power lines." FIU Digital Commons, 1997. http://digitalcommons.fiu.edu/etd/2075.
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The remote control system proposed in this thesis will introduce the concept that power line can be used for control and communication. Home Automation has used the power line to send commands to control appliances but lacked the ability to achieve a two-way communication. The protocol used in Home Automation is not designed for communication and lacks some basics, like error detection.
This thesis will not only use X-10 technology to communicate through the power line but will also implement a VHDL design used for the two-way communication.
A cableless communication is developed using the power line since no new cabling is needed for communication. They greatly ease the work required to install a network, particularly in older buildings that were not built with cabling needs in mind.
X-10 is not the only method that can be used for communication through the power line. A solution that needs further development is mentioned in the conclusion of this thesis.
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Heath, Claude P. R. "Drawing out interaction : lines around shared space." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8817.
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Despite advances in image, video, and motion capture technologies, human interactions are frequently represented as line drawings. Intuitively, drawings provide a useful way of filtering complex, dynamic sequences to produce concise representations of interaction. They also make it possible to represent phenomena such as topic spaces, that do not have a concrete physical manifestation. However, the processes involved in producing these drawings, the advantages and limitations of line drawings as representations, and the implications of drawing as an analytic method have not previously been investigated. This thesis explores the use of drawings to represent human interaction and is informed by the prior experience and abilities of the investigator as a practising visual artist. It begins by discussing the drawing process and how it has been used to capture human activities. Key drawing techniques are identified and tested against an excerpt from an interaction between architects. A series of new drawings are constructed to depict one scene from this interaction, highlighting the contrasts between each drawing technique and their impact on the way shared spaces are represented. A second series of original drawings are produced exploring new ways of representing these spaces, leading to a proposal for a field-based approach that combines gesture paths, fields, and human figures to create a richer analytic representation. A protocol for using this approach to analyse video in practice is developed and evaluated though a sequence of three participatory workshops for researchers in human interaction. The results suggest that the field based process of drawing facilitates the production of spatially enriched graphical representations of qualitative spaces. The thesis concludes that the use of drawing to explore non-metric approaches to shared interactional space, has implications for research in human interaction, interaction design, clinical psychology, anthropology, and discourse analysis, and will find form in new new approaches to contemporary artistic practice.
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Leung, Christopher. "Distributed resource allocation algorithms for digital subscriber lines." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103633.
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The Digital Subscriber Line (DSL) environment is characterized by highly frequency-selective attenuation and by potentially large crosstalk between users. DSL resource allocation algorithms allow for an efficient use of the DSL network by managing the crosstalk-induced interference while also taking the frequency-selectivity into account. Previous resource allocation algorithms were based on worst-case situations. The more recent Dynamic Spectrum Management (DSM) resource allocation algorithms are able to constantly adapt to the channel characteristics. At one end of the DSM algorithms, there is the low-performing user-level Iterative Water-Filling (IWF) algorithm with low computational complexity and full distributivity. At the other end, the better-performing network-level algorithms are not fully distributable and have higher computational complexities.In this thesis, an overview of the DSL environment and its resource allocation algorithms is presented. Then, three alternatives with a smaller computational load than the bisection method used in IWF's water-filling sub-algorithm are presented. These alternatives include a novel projection method for a specific case and the novel Generalized Recursive Water-Filling (GRWF) algorithm for the generalized resource allocation problem.The Autonomous Spectrum Balancing using Multiple Reference Lines (ASB-MRL) algorithm is then presented as an algorithm capable of bridging the performance gap between the fully-distributable and low-complexity IWF, and the high-performing network-level algorithms while maintaining the benefits of each. Following that, a set of conditions on the virtual network formed by the multiple reference lines is produced to ensure that ASB-MRL allocates the resources in a near-optimal manner.L'environnement des lignes d'abonné numérique (DSL) est caractérisé par un affaiblissement progressif de fréquences et une diaphonie potentiellement large entre utilisateurs. L'allocation de ressources dans le DSL permet d'utiliser le réseau DSL efficacement en gérant l'interférence produite par la diaphonie tout en prenant en compte l'affaiblissement progressif de fréquences. Les algorithmes d'allocation de ressources antérieurs étaient construits sur les principes de la pire éventualité. Plus récemment, la gestion dynamique du spectre (DSM) a permis aux algorithmes d'allocation de ressources de s'adapter continuellement aux caractéristiques des voies de transmission et cela a permis le développement de quelques algorithmes. D'un côté, il y a le remplissage d'eau itératif (IWF), un algorithme à faible complexité opérationnelle qui peut être implémenté indépendamment par chaque utilisateur. D'un autre côté, il y a les algorithmes qui gèrent tous les utilisateurs afin d'allouer les ressources beaucoup plus efficacement que le IWF. Par contre, ces algorithmes ne peuvent pas être complètement distribués parmi les utilisateurs et ils ont une plus grande complexité. Dans ce mémoire de maîtrise, un aperçu de l'environnement DSL et des algorithmes d'allocation de ressources est introduit. Ensuite, trois alternatives pouvant s'exécuter plus rapidement que la méthode par bissection utilisée dans le sous-algorithme du IWF sont présentées. Parmi ces alternatives, une nouvelle méthode par projection est proposée pour des cas spéciaux, et une nouvelle méthode se basant sur la récursivité, le remplissage d'eau récursif généralisé (GRWF), est proposée pour les problèmes d'allocation de ressources généralisés. L'algorithme d'équilibre de spectre autonome utilisant plusieurs lignes de référence (ASB-MRL) est ensuite présenté comme un algorithme capable d'obtenir une performance similaire aux algorithmes qui gèrent les ressources de tous les utilisateurs. Toutefois, le ASB-MRL retient les avantages du IWF: la faible complexité et l'implémentation distribué. Par la suite, un ensemble de conditions sur le réseau DSL virtuel contenant les lignes de référence est introduit pour s'assurer que le ASB-MRL alloue les ressources de façon quasi-optimale.
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Svahnberg, Mikael. "Variability in Evolving Software Product Lines." Licentiate thesis, Karlskrona, Sweden : Kaserntryckeriet AB, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00174.
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Software reuse is perceived as the key to successful software development because of the potential for shortened time to market, increased quality and reduced costs. In recent years software product lines have emerged as a promising way to achieve large scale software reuse. Challenges against successful reuse when developing in a software product line involves management of the differences between products, and the differences between different releases of the products. In this thesis we present the experiences from a series of case studies within four software companies. Based on these we present a taxonomy of the technical solutions to manage product differences, a historical essay of how components in a software product line can evolve and what mechanisms that are used to support this evolution. From this we elaborate on the connection between evolution and variability, i.e. the ability of the software architecture and components to support the differences between products. We argue that evolution is strongly connected to variability, and that by foreseeing the evolution, the software can be instrumented with appropriate variability mechanisms accordingly. Moreover, we argue that some types of evolution are more frequent than others, and that the efforts should mainly go in the direction of foreseeing and instrumenting for these types of evolution.
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Hussin, Mohd Fahmi. "Voltage transducer for fault monitoring on high voltage overhead lines." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/65731/.
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Overhead lines are the backbone of electrical power transmission. In most cases, the overhead line provides the best economic and practical solution for energy transmission. Nevertheless, overhead lines suffer more faults due to the vulnerability of the overhead lines to adverse weather condition, transient overvoltage and falling trees. An extensive literature review of existing condition monitoring and impulse a voltage measurement technique of overhead lines are covered in this work, and ultimately leads to the development of the proposed voltage transducer. Although conventional transducers such as voltage transformers and voltage dividers are widely used for monitoring and voltage measurement, yet they have several drawbacks in terms of their size and cost. These are the key factors that limit their widespread deployment for monitoring and measuring voltage on overhead lines and, in particular, rural areas. The proposed transducer is based on a non-contact capacitive voltage probe developed at Cardiff University. However, the proposed transducer uses a high voltage conductor rather than the ground as a measurement reference. The proposed transducer is based on a cylindrical-shaped in order to avoid sharp edges, which can initiate a partial discharge effect. Commercial numerical field computation software packages are used to assist in the development of the proposed transducer for simulation of the electric field distributions around the HV conductor and the transducer. The computed electric field magnitudes obtained on the sensing probe surface are then used for calibration of the proposed transducer. The proposed transducer is developed using low cost materials and tested in a laboratory environment with a low amplitude impulse supply using a surge generator and the corresponding output voltage amplitude obtained from the transducer was validated against a low ac voltage supply using variable output voltage source. The effects of variation in the input voltage, the integrating capacitor inserted between the HV conductor and the sensing probe and height of the transducer above ground on the output voltage amplitude are also investigated. The developed transducer is subsequently tested in field experiments using test overhead lines with low and high voltage supplies. Only a single-phase measurement setup was used in this test as there is only one voltage transducer fabricated in this work. Therefore, each phase of the overhead line was tested individually. Results obtained from the laboratory and field experiments have demonstrated the suitability of the developed transducer for measuring both ac and impulse voltages, which would be useful for fault monitoring on the high voltage overhead lines. However, the computed results obtained from the simulation demonstrated the presence of end-effects at the transducer sensing probe edges. Therefore, an improved design was proposed in this work by introducing a floating electrode between the sensing probe and the guard electrode, with the aim to reduce the fringing effects by preventing the sensing probe from sensing unwanted electric field. The physical development of this improved transducer design is yet to be initiated, and is thus proposed for future work.
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Roshan, Fekr Masoud. "Dynamic response of overhead transmission lines to ice shedding." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23374.
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The main objective of this research was to study dynamic effects of ice shedding on overhead transmission lines using a reliable numerical model.Overhead transmission lines are subjected to various static and dynamic loads. Ice shedding from the conductors is one of the dynamic loads occurring in cold regions. This phenomenon happens when glaze ice formed on the cables suddenly falls under certain temperature and wind conditions. In extreme instances, clashing and breakage of insulator and conductors are potential consequences of these dynamic forces. Maximum vertical cable jumps and drops in unloaded and loaded spans, and axial cable stresses are particular concerns.
The main assumptions and limitations of the proposed numerical model are discussed in detail, with appropriate stiffness, mass, damping, and ice-shedding load modelling. A nonlinear finite-element model using a commercial software (ADINA) was used to carry out simulations of 21 different ice-shedding scenarios varying the number of successive spans involved, the amount of ice accreted on the cables, different elevations of the central support, partial and sub-span ice shedding and the configuration and sequence of the shedding in adjacent spans. The analysis of the results focuses on the peak cable tensions generated, the insulator string swings and the maximum transient in-span cable displacements. Some of the results are compared with the design procedures used at Hydro-Quebec, which is based on static analysis.
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Humbert, Matthew S. "Physically modeling and mathematically simulating pressure transients in transfer lines." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45840.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Characterizing transient flow is not a trivial venture. It provides an excellent challenge for a senior mechanical engineering lab class. This project aimed at developing a new physical system for such a class based on the benefits and short comings of the previously used physical system. A physical system was developed to vary key parameters, such as run length and pipe diameter. Pipe diameter was previously not a variable parameter. The physical system was designed to help the operator's intuition in developing a mathematical model for said system. The design incorporated solenoid valves and clear pipe. In contrast to the previous system that used ball valves and copper pipe. These features were chosen so that those using the system could neglect human error and visually inspect the flow. The system was designed to increase variation between runs so that a more robust model could be developed. The flexibility of the physical system allows for the examination of more complex flows than the previous system. The mathematical model that was developed characterized the flow reasonably well. The unsteady Bernoulli equation was implemented with major and minor losses. The model revealed several aspects of the physical system that were not immediately obvious from the data. The unpredicted aspects of the physical system were the fluctuation in tank pressure over the test duration and the correlation between tank pressure and the loss coefficient of the main solenoid valve. The higher the pressure the lower the loss coefficient across the valve. The mathematical model did not account for losses that increase as the water air interface moves through different fittings. This was a major shortcoming of the mathematical model that was developed.
by Matthew S. Humbert.
S.B.
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Irfan, Nazish. "Simulation of incident field coupling with nonuniform transmission lines." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27855.
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This thesis develops a new algorithm to simulate incident field coupling with high-speed interconnects. The interconnects considered in this thesis are represented by nonuniform multi-conductor transmission lines and are described through the Telegraphers Equations. The developed algorithm is based on the concept of model-order reduction via projection onto Hilbert space, where a reduced-order model representing the transmission line is constructed and employed as a stamp for representing the line. The incident field is represented by a set of terminal sources obtained from the projection operator used in constructing the reduced-order model. In addition to being developed to handle nonuniform transmission lines, the proposed algorithm offers an advantage by guaranteeing the passivity of the reduced order model. Several examples are presented to validate the validity and accuracy of the proposed algorithm.
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Herbas, Jose Antonio Mercado. "Capturing Architectural Knowledge of Software Product Lines." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-5206.
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The architecture of a software system is defined by significant decisions that drive the way in which the software is designed implemented and maintained. In the context of software product lines, these decisions will determine the design of an architec- ture that provides the software with the ability to be configured for different product variants and extended to accommodate future requirements. Although, variability models describe the different configurations of current and fu- ture products that the product line supports, the knowledge of how the architecture was designed to support variations of a product in space and time exists only in the architects’ mind or remains implicit in architectural models. This thesis argues that the knowledge found in architectural models and design rationale can be used to facilitate the derivation of product variants and the evolution of the product line. To support this notion, we propose the AKinSPL method for capturing the architec- tural knowledge in software product lines. The method is founded on the factors that architects take into consideration when designing the architecture, and a meta-model that represents the mental models and processes architects follow during the creation of a product line architecture. To validate the concepts of AKinSPL, its guidelines were mapped to activities of the PuLSE-DSSA methodology and new artifacts were created to capture architectural knowledge on the basis of those guidelines. Next, it was applied to capture the archi- tectural knowledge of an embedded software system for automatic control of agricul- tural equipment. The results showed that diagrams augmented with design rationale enable a faster understanding of the purpose of the architectural models. Similarly, the prescriptions of the architecture with respect to the implementation are conveyed more easily.jmercadoh@gmail.com Tel: +4916099058545
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Trudel, Nathalie. "Gene expression profile in human prostate cancer cell lines." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33449.
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Since the beginning of this work in 1998, it is estimated that 1780 men died of prostate cancer in Quebec. Molecular analysis of prostate cancer will eventually lead to the discovery of key genes involved in its onset and progression. The present project was to compare gene expression profiles in human non-tumorigenic versus tumorigenic prostate cell lines generated in our laboratory. A putative tumor suppressor gene present on 12q13 would be responsible for the non-tumorigenic phenotype of one cell line as discovered earlier by our team.In order to compare gene expression patterns, expression arrays from Clontech, bearing 588 genes known to be involved in human cancers, were hybridized with cDNA derived from two related cell lines available in our laboratory. This one experiment provided interesting hints on differentially expressed genes that could be involved in human prostate cancer. Interesting clones were confirmed by Northern blots. When commercial antibody was available, analysis was extended at the protein level. A combination of these analyses revealed no striking difference in the level of expression for the genes previously identified by the arrays hybridization.
Simultaneously, differential display PCR techniques, allowing the discovery of unknown differentially expressed molecules and thus complementing the previous approach, were applied to compare related cell lines and unique hybrids. Cloning and sequencing of differential fragments brought us to what could be a new cDNA expressed in many human cell lines.
Prostate cancer is not well characterized enough to allow accurate diagnosis or appropriate therapy strategies. Differentially expressed molecules analyzed in this project as well as the putative new cDNA might fulfil part of this lack in the understanding of this disease.
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Baumgartner, Claus Ernst 1961. "Simulation methods for multiconductor transmission lines in electronic applications." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/284323.
Full textAbstract:
Accurate and efficient simulation of lossy, multi-conductor transmission lines that are terminated by nonlinear circuits is necessary to design high-performance electronic circuits and packages. In this work, theoretical and practical considerations of lossy line simulation are presented. Using delay differential equations, the class of systems with "bidirectional delay" is introduced. These systems can be partitioned such that the resulting subsystems are only linked via delayed variables. It is stated in the "decoupling theorem" that the subsystems can be solved independently for a time interval, which is not longer than the shortest time delay. Circuits that contain transmission lines are shown to form systems with bidirectional delay and, consequently, can be decoupled. Using concepts derived from waveform relaxation, the decoupling is exploited to reduce the computational effort required for transmission line simulation. Moreover, an efficient method for the approximation of lossy line characteristics by rational transfer functions is presented. The method employs nonlinear minimization techniques and yields function coefficients suitable for time-domain modeling. Furthermore, the exponential wave propagation function is represented in the time domain, and discrete-time convolution is employed to calculate the transmission line response. Also described is a filtering method which considerably improves the stability of the simulation, while the deviation in the simulation results is smaller than the local truncation error. In addition, implementation of the lossy line simulator "UAFLICS" is outlined, and practical applications demonstrate the significance of coupling and loss effects.
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Tax, David S. (David Samuel). "Mode conversation losses in overmolded millimeter wave transmission lines." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45855.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 106-109).
Millimeter wave transmission lines are integral components for many important applications like nuclear fusion and NMR spectroscopy. In low loss corrugated transmission lines propagating the HE,1 mode with a high waveguide radius to wavelength ratio (a/X), the transmission line loss is predominantly a result of mode conversion in components such as miter bends. The theory for determining losses in miter bends though is only approximate, and is based instead on the problem of the loss across a diameter-length gap between two waveguide sections. Through simulation, we verified that the existing analytic theory of this gap loss is correct; however, our simulations could not verify the assumption that the miter bend loss is half the loss in the gap. We also considered the problem of higher order modes (HOMs) mixed with an HE11 input entering the miter bend. Using a numerical technique, we found that the loss through the miter bend is dependent on both the amplitude of the HOM content as well as its phase relative to the phase of the HE11 mode. While the overall loss averaged across all phases remains the same with increasing HOM content, the power that fails to traverse the gap tends to increase, and it is this power that appears as very high order modes that will cause heating around the miter bend. For the ITER transmission line, the loss based on gap theory is 0.027 dB and, using a coherent technique, we measured a loss of 0.05 + 0.02 dB with a vector network analyzer (VNA).
(cont.) We also set out to measure the mode conversion caused by a miter bend by using a 3-axis scanner system to measure the field patterns within the ITER waveguide. Due to the presence of higher order modes output by the HE I launcher, definitive results on the mode conversion attributed to the miter bend could not be obtained. Using a phase retrieval code, we were able to calculate the mode purity of the launcher output and found it to be 98 + 0.5 %. Future work will concentrate on reducing this HOM content to enable measurements of the miter bend mode conversion.
by David S. Tax.
S.M.
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Hagen, Roger Ebbe-Jan. "An algorithm for incremental anti-aliased lines and curves." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14583.
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Peyman, John A. "Membrane and azurophilic granule proteins of human myeloid leukemia cell lines." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72799.
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Alizadeh, Pahlavan Amir. "Moving contact lines, wetting transitions and interfacial instabilities in confined environments." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120249.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 211-262).
Immiscible fluid flows are ubiquitous in nature and industry, from multiphase-flow phenomena on geologic scales such as CO2 sequestration and methane venting from seafloor sediments to bubble/drop/emulsion generation in microfluidic techniques. All these flows are inherently multi-scale, from the intermolecular interactions on the nanometer scale in the vicinity of contact lines, where fluid phases meet the surrounding solid surface, to the micrometer scale of the confinement in a pore or microfluidic device, and finally to kilometer scale of the natural geologic phenomena. The multi-scale nature of immiscible fluid flows combined with the inherent disorder present in many natural or industrial systems renders description of these flows a formidable task. Here, using a combination of experimental observations and theoretical modeling we show that the interplay between confinement and contact line motion leads to novel and non-trivial consequences on the dynamics and instability of immiscible fluid fronts. We first present a theoretical model for thin-film flows on solid surfaces in the partial wetting regime and show that a self-consistent description of free energy of this system at equilibrium leads to a Cahn-Hilliard form with an effective height-dependent surface tension due to the interniolecular forces in the vicinity of the contact line. Within the framework of non-equilibrium thermodynamics, we then study the consequences of this new form of free energy on the spreading of drops and dewetting of thin films in the partial wetting regime. We show that on macroscopic scales, our model recovers the classic hydrodynamic Cox-Voinov description of moving contact lines and is consistent with experimental observations. We further show that on the microscopic scale our model is consistent with the molecular kinetic theory, therefore bridging the gap between the two descriptions across the scales. We finally show that our model captures the dynamics of nanometric dewetting thin films in spinodal and nucleation regimes as well as their long-time coarsening behavior and brings the theoretical predictions closer to the previous experimental observations. We then revisit the classic Taylor-Bretherton problem in the partial wetting regime, where air displaces a highly viscous liquid in a capillary tube. In contrast with the classic results for complete wetting, we show that the presence of a moving contact line induces a wetting transition at a critical capillary number that is contact angle dependent. Beyond wetting transition, a film of the defending liquid coats the tube walls. The entrained liquid film immediately starts receding along the tube wall, forming a growing dewetting rim behind the contact line, which finally leads to the breakup of the bubble. The bubble pinch-off is an example of singularity formation, where separation of length scales close to the point of singularity are expected to lead to self-similar and universal dynamics. We show that the breakup of a bubble confined in a capillary tube undergoes a sequence of two distinct self-similar regimes even though the balance remains between viscous and surface-tension forces. While the breakup of a bubble in an unbounded reservoir is known to be non-universal, we demonstrate that the presence of the early-time self-similar regime in a confined system effectively erases the system's memory and restores universality to bubble breakup. We then revisit the classic Saffinan-Taylor instability in the imbibition regime, where a more wetting and less viscous liquid displaces a less wetting and more viscous liquid in a radial Hele-Shaw cell (two plates separated by a small gap). We show that the wetting liquid invades the cell in the form of a thin-film front, which becomes unstable and leads to a viscous fingering pattern. To gain an understanding of the front dynamics, we develop a thin-film model, which predicts the base state of the invading thin films to be an undercompressive shock, which has previously been shown to lead to stable fronts. Using linear stability analysis and nonlinear simulations, we show that consistent with our experimental observations the thin film front in a Hele-Shaw cell is unstable. The instability here is due to the pressure coupling between the two fluid flows in a confined domain. We further show that the scaling of the wavelength of instability in thin-film front is different from the Saffman-Taylor instability, suggesting that it belongs to a new pattern formation class. In the final part of this thesis, we explore how the interplay between wetting and disorder influences the pattern formation. We introduce disorder into the Hele-Shaw system by making one of the surfaces randomly rough. In particular, we show that in the imbibition regime aside from the primary thin films that we observed in smooth cells, secondary thin films of the scale of roughness appear. These secondary films wick into the crevices of the rough surface with a diffusive dynamics and change the effective wettability of the medium. We therefore show that disorder on the micro-scale affects the macroscopic morphology of unstable fluid fronts.
by Amir Alizadeh Pahlavan.
Ph. D.
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Larrier, Nicole A. (Nichole Alison). "Screening for apoptosis in breast cancer cell lines using gel electophoresis." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37030.
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Mtanga, Jameson Joseph. "Dynamic modeling and vibration control of high-voltage overhead transmission lines." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/5022.
Full textAbstract:
Includes abstract.Includes bibliographical references (leaves 140-144).
The problem of the dynamic behavior of overhead power transmission lines under wind and other excitations is an important one, since it allows an optimal design and positioning of vibration dampers for the cables. Excessive sway and oscillation of power lines need to be avoided, as they can lead to damage of the lines and power interruptions. The relatively high flexibility of the cables, coupled with the large spans and large sags involved, make the dynamic response of the system highly nonlinear. In this study, we numerically investigate the damped free-vibration response of systems of cables of particularly large spans (120, 200 and 400m).
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Akinnikawe, Ayorinde. "Investigation of broadband over power line channel capacity of shipboard power system cables for ship communications networks." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3155.
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Habtemariam, Filmon A. "HIGH-FREQUENCY IMPEDANCE CHARACTERISTICS AND HEALTH CONDITION MONITORING OF OVERHEAD POWER LINES." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1472735633.
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Babany, Michel David. "Decision support for disruption management on high frequency transit lines." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99549.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 155-159).
Incidents (due to equipment failures, passenger emergencies, infrastructure problems, human errors, etc.) routinely occur in metro systems. Such incidents can cause significant disruptions in service (from slowdown to full closure of the line), with serious impacts on passengers, especially in the core of high frequency lines operating near capacity. Disruption consists of two distinct phases. The incident phase is the period from the start of the incident to the moment when its cause has been resolved. The second phase of the disruption is the recovery, which starts at the end of the incident and lasts until normal service is restored. Dealing efficiently with disruptions is crucial and agencies use real-time control strategies to mitigate those impacts and improve performance. This thesis proposes an approach for supporting controllers decision-making in the recovery phase of disruption management. While the method is applied to the Piccadilly Line on the London Underground, It is applicable to other high frequency transit rail lines. After reviewing the main challenges controllers face during incident management and the main strategies they use, the thesis formulates the recovery phase problem as an optimization problem that integrates timetable revision and crew rescheduling (train reformation problem, TRP). The approach focuses on modeling common control strategies such as short-turning and train renumbering. It explicitly incorporates the scarcity of resources and associated constraints, especially with respect to crews. The method consists of two phases: the generation of a large number of candidate journeys; and the selection of the journeys (recovery timetable) that optimize some measure of performance, involving the effectiveness of the recovery and the passenger service. The model is first applied to an incident that happened on January 2014 on the Piccadilly Line. The actual controllers response is compared with the output of the train reformation problem, and a sensitivity analysis of the model parameters is performed. The results suggest that using more complex reformations and less short-turns may lead to better passenger service during the recovery phase. The train reformation problem is then applied to a hypothetical incident. The results support current practices that canceling trains during the incident phase enables a shorter and more efficient recovery.
by Michel David Babany.
S.M.
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Di, Silvestro Fabio. "Improving testing reusability and automation for software product lines." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-48635.
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Software product lines are widely used in industrial environments for developing complex software systems. One of the main advantages deriving from the adoption of this software engineering development methodology is increased reusability. In fact, software product lines offer convenient means for representing different products belonging to the same family and different families of products by grouping shared functionalities and highlighting differences. Despite software product lines inherently improve the design and the development of complex software systems, they usually require ad-hoc strategies for the testing of such systems.To this end, testing strategies for software product lines need to account for the extensive amount of artefacts reuse and for possible differences among such artefact, too.In fact, even though software product line products might share several functionalities, the interfaces of such functionalities might differ due to the specificities imposed by the products or their designs. In this thesis, we propose a testing approach for software product lines, which allows to test functionalities that are shared among the products, accounting for the potential heterogeneity of the exposed interfaces.The main contribution of this approach is the definition of generic test-cases from which product-specific test-scripts are automatically generated, so to enhance the reusability of the handcrafted artefacts and overcome the issue of different interfaces.What is more, the proposed approach discloses the opportunity to reduce the time required to develop testing artefacts.
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Elnaddab, Khalifa. "Evaluation of Gas Insulated Lines (GIL) for long distance HVAC power transfer." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/73315/.
Full textAbstract:
Offshore wind power is a key element in EU policies to reduce the greenhouse effect and secure energy sources. In order to accomplish the EU’s target of a 20% share of energy from renewable sources by 2020, some of the planned projects have to be placed far away from the shoreline to benefit from the high wind speeds in the open sea area. However, a traditional transmission system for offshore wind farms based on a High Voltage Alternating Current (HVAC) utilizing conventional cables is not appropriate for long distances. In contrast, a High Voltage Direct Current (HVDC) can transmit electrical power over such distances, but the complicated concept of converting the HVAC offshore generated power into DC and then converting the DC power at the onshore grid back to AC requires sophisticated and expensive converter stations at both ends. Therefore, developing a new infrastructure solution based on HVAC transmission technology, which has been in operation for more than a century and which runs almost entire electrical systems, to support and advance the development of offshore wind energy is a highly desirable outcome. This research work was conducted to examine and determine the suitability of using an HVAC gas-insulated transmission line (GIL) as a long-distance transmission system for offshore wind farms in terms of technical and economic costs. A computer model of GIL has been built using the Electromagnetic Transient Program (EMTP) to assess the suitability of GIL and quantify the voltage, current and power transfer characteristics of the GIL under different steady state conditions. Furthermore, a suitable model has been developed for the simulation of the switching transient during energisation of the GIL transmission system and various wind farm components. The development concept of GIL as a submarine Power Transmission Pipeline (PTP) is described, and the practical side of installing the PTP technology and the special design requirements of the offshore wind farms were illustrated. The PTP components, the maximum transmission capacity of the PTP system and the layout options were addressed. In addition, the challenges facing this technology were discussed. An economic comparison of the total cost for both HVAC-GIL and HVDC-VSC transmission systems is made, including annual costs (operation, maintenance, and losses) during the lifetime of the projects. The initial investment costs are added to the annual costs in order to obtain the total cost for the assumed project. Furthermore, the Power Transmission Cost (PTC) is calculated for each MVA-km being delivered to the receiving end of the GIL transmission line.
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Gyurecz, György, and Tibor Bercsey. "Surface Shape Correction by Highlight Lines." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-228739.
Full textAbstract:
The design of industrial products applies various construction aspects. Beside functionality and manufacturability conditions that are essential in technical design, products must also meet aerodynamic, hydrodynamic and aesthetic demands. These demands are particularly important in automotive, ship and airplane industry but they are also present in the design of medical replacements, household appliances, etc. The common objective of above aspects is to produce smooth and irregularity free surface shape. Quality and smoothness of surfaces of industrial objects can efficiently be evaluated by highlight lines.