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Dissertations / Theses on the topic 'SIMO systems'

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Published: 3 June 2025

Last updated: 13 July 2025

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Karakutuk, Serkan. "Blind And Semi-blind Channel Order Estimation In Simo Systems." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611107/index.pdf.

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Channel order estimation is an important problem in many fields including signal processing, communications, acoustics, and more. In this thesis, blind channel order estimation problem is considered for single-input, multi-output (SIMO) FIR systems. The problem is to estimate the effective channel order for the SIMO system given only the output samples corrupted by noise. Two new methods for channel order estimation are presented. These methods have several useful features compared to the currently known techniques. They are guaranteed to find the true channel order for noise free case and they perform significantly better for noisy observations. These algorithms show a consistent performance when the number of observations, channels and channel order are changed. The proposed algorithms are integrated with the least squares smoothing (LSS) algorithm for blind identification of the channel coefficients. LSS algorithm is selected since it is a deterministic algorithm and has some additional features suitable for order estimation. The proposed algorithms are compared with a variety of dierent algorithms including linear prediction (LP) based methods. LP approaches are known to be robust to channel order overestimation. In this thesis, it is shown that significant gain can be obtained compared to LP based approaches when the proposed techniques are used. The proposed algorithms are also compared with the oversampled single-input, single-output (SISO) system with a generic decision feedback equalizer, and better mean-square error performance is observed for the blind setting. Channel order estimation problem is also investigated for semi-blind systems where a pilot signal is used which is known at the receiver. In this case, two new methods are proposed which exploit the pilot signal in dierent ways. When both unknown and pilot symbols are used, a better estimation performance can be achieved compared to the proposed blind methods. The semi-blind approach is especially effective in terms of bit error rate (BER) evaluation thanks to the use of pilot symbols in better estimation of channel coecients. This approach is also more robust to ill-conditioned channels. The constraints for these approaches, such as synchronization, and the decrease in throughput still make the blind approaches a good alternative for channel order estimation. True and effective channel order estimation topics are discussed in detail and several simulations are done in order to show the significant performance gain achieved by the proposed methods.

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Ngo, Hien Quoc, Michail Matthaiou, Trung Q. Duong, and Erik G. Larsson. "Uplink Performance Analysis of Multicell MU-SIMO Systems with ZF Receivers." Linköpings universitet, Kommunikationssystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-92849.

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We consider the uplink of a multicell multiuser single-input multiple-output system where the channel experiences both small and large-scale fading. The data detection is done by using the linear zero-forcing technique, assuming the base station (BS) has perfect channel state information of all users in its cell. We derive new, exact analytical expressions for the uplink rate, symbol error rate, and outage probability per user, as well as alower bound on the achievable rate. This bound is very tight and becomes exact in the large-number-of-antennas limit. We further study the asymptotic system performance in the regimes of high signal-to-noise ratio (SNR), large number of antennas, and large number of users per cell. We show that at high SNRs, the system is interference-limited and hence, we cannot improve the system performance by increasing the transmit power of each user. Instead, by increasing the number of BS antennas, the effects of interference and noise can be reduced, thereby improving the system performance. We demonstrate that, with very large antenna arrays at the BS, the transmit power of each user can be made inversely proportional to the number of BS antennas while maintaining a desired quality-of-service. Numerical results are presented to verify our analysis.

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Gao, Bo 1981. "Computationally efficient approaches for blind adaptive beamforming in SIMO-OFDM systems." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115994.

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In single-input multiple-output (SIMO) systems based on orthogonal frequency division multiplexing (OFDM), adaptive beamforming at the receiver side can be used to combat the effect of directional co-channel interference (CCI). Since pilot-aided beamforming suffers from consuming precious channel bandwidth, there has been much interest in blind beamforming approaches that can adapt their weights by restoring certain properties of the transmitted signals. Within this class of blind algorithms, the recursive least squares constant modulus algorithm (RLS-CMA) is of particular interest due to its good overall CCI cancelation performance and fast convergence. Nevertheless, the direct use of RSL-CMA within a SIMO-OFDM receiver induces considerable computational complexity, since a distinct copy of the RLS-CMA must be run on each individual sub-carriers. In this thesis, we present two approaches to reduce the computational complexity of SIMO-OFDM beamforming based on the RLS-CMA, namely: frequency interpolation and distributed processing. The former approach, which exploits the coherence bandwidth of the broadband wireless channels, divides the sub-carriers into several contiguous groups and applies the RLS-CMA to a selected sub-carrier in each group. The weight vectors at other frequencies are then obtained by interpolation. The distributed processing approach relies on the partitioning of the receiving array into sub-arrays and the use of a special approximation in the RLS-CMA. This allows a partial decoupling of the algorithm which can then be run on multiple processors with reduced overall complexity. This approach is well-suited to collaborative beamforming i~ multi-node distributed relaying. Through numerical simulation experiments of a SIMO-OFDM system, it is demonstrated that the proposed modifications to the RLS-CMA scheme can lead to substantial computational savings with minimal losses in adaptive cancelation performance.

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Hu, Mathieu. "Cross-relation based blind identification of acoustic SIMO systems and applications." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/52430.

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Speech signals captured by microphones placed at a distance from the speaker are cor- rupted by reverberation, i.e. sound waves reflected off hard surfaces such as walls and objects. The spectral distortion caused by reverberation drastically decreases the perfor- mance of automatic speech recognition systems and may degrade the intelligibility and the quality of speech for human listeners. The increased use of devices controlled by distant speech therefore induces the need for dereverberation. A possible approach to dereverberation is that of system equalization, which consists of the blind estimation of the room impulse responses from noisy reverberant signals followed by an inversion of these impulse responses. This thesis investigates the first part of this two-stage approach. The cross-relation method is adopted and exploited in two different ways. The first way follows the adaptive filter framework, which was first introduced in the context of blind identification of room impulses responses in the Multi-Channel Least Mean Square. By considering a block update of this stochastic gradient algorithm, a noise robust algorithm is developed. The convergence rate of the resulting algorithm is then increased by using a locally optimal adaptive step-size. The cross-relation, expressed in the frequency domain, is then shown to contain the transfer function relating any of the microphone to a reference microphone. This relative transfer function can be used to reduce the number of variables to be estimated. However, the performance of the previous methods severely degrades when realisti- cally long room impulse responses are considered. An alternative interpretation of the cross-relation, from an annihilation filter perspective, is therefore explored. The resulting algorithm is shown to be able to estimate room impulse responses of thousands of taps. From a more practical perspective, the use of room impulses estimated at a poor accuracy is investigated for the problem of speaker diarization. The spatial information captured in the direct-to-reverberant ratio is shown to be robust to high levels of errors in the estimated room impulse responses. Blindly estimated direct-to-reverberant ratios combined with speech features in a single-channel diarization system are shown to provide additional information, which improves the performance of the diarization system.

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Bahri, Nesrine. "Une commande neuronale adaptative basée sur des émulateurs neuronal et multimodèle pour les systèmes non linéaires MIMO et SIMO." Thesis, Le Havre, 2015. http://www.theses.fr/2015LEHA0024/document.

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La porosité d'une plaque composite carbone / époxy de type RTM est connue par tomographie X. Une méthode de détermination de cette porosité par mesure de l'atténuation des ondes longitudinales à travers l'épaisseur de cette plaque est proposée. Ces mesures sont effectuées sur des surfaces de dimensions variables (quelques cm2 à quelques mm2) et permettent l’obtention de cartographies. Une correspondance porosité (tomo X) – atténuation (onde US) est déduite et analysée en fonction de la structure du matériau composite. Dans chaque cas, on estime la qualité des relations obtenues et on en déduit les limites de validité de la correspondance porosité-atténuation. Des premiers résultats de tomographie acoustiques sont obtenus The porosity of a composite plate in carbon / epoxy of type RTM is known by used of tomography X. A method of determination of this porosity by measure of the mitigation of the longitudinal waves through the thickness of this kind of plate is proposed. These measures are made on surfaces of different sizes (from some cm2 to some mm2) and allow the obtaining of cartographies. A correspondence porosity (tomo X) - Mitigation (US wave) is deducted and analyzed according to the structure of the composite material. In every case, we estimate the quality of the obtained relations and we deduct the limits of validity of the correspondence between porosity and mitigation. First results of acoustic tomography are obtained

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Costa, Michele Nazareth da 1984. "Um estudo sobre as condições de inversão perfeita e de equalização não-supervisionada de canais SISO, SIMO e MIMO." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259287.

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Orientador: João Marcos Travassos Romano, Ricardo Suyama Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação Made available in DSpace on 2018-08-14T00:41:40Z (GMT). No. of bitstreams: 1 Costa_MicheleNazarethda_M.pdf: 1765125 bytes, checksum: ca7881285ef04b9d9226595f3dd1e90c (MD5) Previous issue date: 2009 Resumo: Esta dissertação teve como motivação inicial a busca de uma abordagem unificada para o problema de equalização não-supervisionada, a ser aplicada às configurações SISO, SIMO e MIMO. Tal abordagem se refere a dois aspectos fundamentais do problema: a estrutura do equalizador e a otimização de seus parâmetros. Desta forma, propomos uma mesma metodologia para estudar, nas três configurações citadas, o que denominamos de limitação estrutural e de limitação de critério. A primeira é caracterizada pela impossibilidade de inversão perfeita do canal fazendo uso de apenas filtros com resposta impulsiva finita (FIR); a segunda se refere às limitações quanto ao uso de estatísticas de ordem dois (EO2) para a obtenção do equalizador ótimo no caso não-supervisionado. Para tal análise, reunimos resultados um tanto dispersos na literatura para formalizar de maneira unificada e acessível os conceitos de sistema inversível e de sistema de fase mínima para as três configurações. Em seguida, empregamos o conceito de filtro de erro de predição linear para estudar o uso de EO2 em equalização, estendendo esse conceito também às três configurações Abstract: This dissertation was motivated by the idea of developing a unified approach to the problem of unsupervised equalization, in the context of SISO, SIMO and MIMO channels. This approach is concerned with two fundamental aspects of the equalization problem: the structure of the equalizer and the optimization of its parameters. In this sense, we propose a same methodology to study, in the three aforementioned scenarios, two different limitations. The first one, which we denote structural limitation, is related to the impossibility of inverting any channel employing only finite impulse response (FIR) filters. The second one, which we call criterion limitation, refers to the limitation regarding the use of second order statistics (SOS) to obtain the equalizer in an unsupervised manner. In order to perform this analysis, we collected results that are rather scattered in the literature to formalize the concepts of invertible and minimum-phase systems in all three scenarios. Then, we use the concept of a prediction-error filter to study the limitation of SOS in the equalization problem Mestrado Telecomunicações e Telemática Mestre em Engenharia Elétrica

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Krishnan, Narayanan. "Analysis of energy efficiency of cooperative MIMO schemes." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1427.

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Chan, Kwong Hang Kevin. "An Analysis of Wireless High-speed Data Services for Cellular CDMA Systems." Thesis, University of Waterloo, 2002. http://hdl.handle.net/10012/860.

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The interest in the development of wireless high-speed data services is in response to the strong market demand for high-speed wireless Internet access. Current standards aim at delivering a peak data rate greater than 2Mbps on the forward link. Since data services and voice services are fundamentally different, new concepts were introduced in the design of the forward data channel. In addition, methods of evaluating the performance of a cellular CDMA system have to be revisited. This thesis proposes a method which can be used to find the forward link peak and average data rates, throughput and coverage of a cellular CDMA system which is capable of delivering high-speed wireless data. A summary of changes in design philosophy and recent advances in technologies which enable high-speed wireless data delivery are presented. The proposed method takes into account major aspects commonly found in the forward data channel and applies the generalized Shannon capacity formula for multi-element antenna (MEA) systems. The analysis focuses on the physical layer and is flexible enough to be adapted to various propagation environments, antenna configurations, multicode allocations, user distributions and cell site configurations. Sample numerical results for various multicode allocations are shown using a system model with two-tier interfering cells with one transmit antenna and two receive antennas operating under a frequency selective slow fading channel with propagation environment described by the Recommendation ITU-R M. 1225 indoor office, outdoor to indoor and pedestrian and vehicular test environments. Different transmit / receive antenna configurations and multicode allocations and their impact on the average data rate is also explored.

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Rabaça, Ricardo Seriacopi. "Estudo sobre os métodos de diversidade para sistemas de TV digital." Universidade Presbiteriana Mackenzie, 2017. http://tede.mackenzie.br/jspui/handle/tede/3479.

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Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-02-06T23:04:35Z No. of bitstreams: 2 RICARDO SERIACOPI RABAÇA.pdf: 12578451 bytes, checksum: 9aa6f50946d5c917a7ea4e5b6841ef6f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-04-03T12:57:50Z (GMT) No. of bitstreams: 2 RICARDO SERIACOPI RABAÇA.pdf: 12578451 bytes, checksum: 9aa6f50946d5c917a7ea4e5b6841ef6f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Made available in DSpace on 2018-04-03T12:57:50Z (GMT). No. of bitstreams: 2 RICARDO SERIACOPI RABAÇA.pdf: 12578451 bytes, checksum: 9aa6f50946d5c917a7ea4e5b6841ef6f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-08 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Fundo Mackenzie de Pesquisa This project presents the history, basic information and advantages of using Software De ned Radio (SDR), diversity, layer division multiplexing (LDM) technique and the latest digital TV standards in a digital communication system. These subjects have been relevant in the scienti c community, making the project attractive in terms of the possibility of discoveries and optimizations. After that, the implementation of a digital communication system using these technologies is proposed. This implementation was performed by means of GRC simulation software and the use of C++ and Python programming languages. Therefore, it was necessary to test the steps of coding, modulation and digital transmission / reception. Finally, tests were performed with systems that use diversity, for example, Single-Input Single-Output (SISO), as well as setting Single-Input Multiple-Output (SIMO), using the settings 1x 2, 1x3 and 1x4, in order to compare possible advantages in spectrum utilization, data rate and system robustness to interference. O presente projeto apresenta o histórico, as informações básicas e as vantagens da utilização do rádio definido por software, do inglês Software Defined Radio (SDR), da diversidade, da técnica de multiplexacão por divisão em camadas, do inglês Layered Division Multiplexing (LDM) e dos mais modernos padrões de TV digital em um sistema de comunicação digital. Estes temas vêm repercutindo de forma relevante na comunidade científica, tornando o projeto atrativo em termos de possibilidade de descobertas e otimização. Posteriormente, a implementação de um sistema de comunicação digital unindo estas tecnologias _e proposta. Esta implementação foi realizada por meio do software de simulação GNU Radio Companion (GRC) e do uso das linguagens de programação C++ e Python. Para tanto, foi necessário testar as etapas de codificação, modulação e a transmissão/recepção digital. Finalmente, foram realizados testes com sistemas que utilizam diversidade, como, por exemplo, os métodos com uma entrada e uma saída, do inglês Single-Input Single-Output (SISO), além do método com uma entrada e múltiplas saídas, do inglês Single-Input Multiple-Output (SIMO), com as configurações 1x2, 1x3 e 1x4, com o intuito de comparar possíveis vantagens no aproveitamento do espectro, na taxa de dados e na robustez do sistema à interferências.

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Shankar, H. N. "Adaptive Control Of A General Class Of Finite Dimensional Stable LTI Systems." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/225.

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We consider the problem of Adaptive Control of finite-dimensional, stable, Linear Time Invariant (LTI) plants. Amongst such plants, the subclass regarding which an upper bound on the order is not known or which are known to be nonminimum phase (zeros in the unstable region) pose formidable problems in their own right. On one hand, if an upper bound on the order of the plant is not known, adaptive control usually involves some form of order estimation. On the other hand, when the plant is allowed to be either minimum phase or nonminimum phase, the adaptive control problem, as is well-known, becomes considerably-less tractable. In this study, the class of unknown plants considered is such that no information is available on the upper bound of the plant order and, further, the plant may be either minimum phase or nonminimum phase. Albeit known to be stable, such plants throw myriads of challenges in the context of adaptive control. Adaptive control involving such plants has been addressed [79] in a Model Reference Adaptive Control (MRAC) framework. There, the inputs and outputs of the unknown plant are the only quantities available by measurement in terms of which any form of modeling of the unknown plant may be made. Inputs to the reference model have been taken from certain restricted classes of bounded signals. In particular, the three classes of inputs considered are piecewise continuous bounded functions which asymptotically approach • a nonzero constant, • a sinusoid, and • a sinusoid with a nonzero shift. Moreover, the control law is such that adaptation is carried out at specific instants separated by progressively larger intervals of time. The schemes there have been proved to be e-optimal in the sense of a suitably formulated optimality criterion. If, however, the reference model inputs be extended to the class of piecewise continuous bounded functions, that would compound the complexity of the adaptive control problem. Only one attempt [78] in adaptive control in such a setting has come to our notice. The problem there has been tackled by an application of the theory of Pade Approximations to time moments of an LTI system. Based on a time moments estimation procedure, a simple adaptive scheme for Single-Input Single-Output (SISO) systems with only a cascade compensator has been reported. The first chapter is essentially meant to ensure that the problem we seek to address in the field of adaptive control indeed has scope for research. Having defined Adaptive Control, we selectively scan through the literature on LTI systems, with focus on MRAC. We look out in particular for studies involving plants of which not much is known regarding their order and systems which are possibly nonminimum phase. We found no evidence to assert that the problem of adaptive control of stable LTI systems, not necessarily minimum phase and of unknown upper bound on the order, was explored enough, save two attempts involving SISO systems. Taking absence of evidence (of in-depth study) for evidence of absence, we make a case for the problem and formally state it. We preview the thesis. We set two targets before us in Chapter 2. The first is to review one of the existing procedures attacking the problem we intend to address. Since the approach is based on the notion of time moments of an LTI system, and as we are to employ Pade Approximations as a tool, we uncover these concepts to the limited extent of our requirement. The adaptive procedure, Plant Command Modifier Scheme (PCMS) [78], for SISO plants is reported in some detail. It stands supported on an algorithm specially designed to estimate the time moments of an LTI system given no more than its input and output. Model following there has been sought to be achieved by matching the first few time moments of the reference model by the corresponding ones of the overall compensated plant. The plant time moment estimates have been taken to represent the unknown plant. The second of the goals is to analyze PCMS critically so that it may serve as a forerunner to our work. We conclude the chapter after accomplishing these goals. In Chapter 3, we devise a time moment estimator for SISO systems from a perspective which is conceptually equivalent to, yet functionally different from, that appropriated in [78]. It is a recipe to obtain estimates of time moments of a system by computing time moment estimates of system input and output signals measured up to current time. Pade approximations come by handy for this purpose. The lacunae exposed by a critical examination of PCMS in Chapter 2 guide us to progressively refine the estimator. Infirmities in the control part of PCMS too have come to light on our probing into it. A few of these will be fixed by way of fabricating two exclusively cascade compensators. We encounter some more issues, traceable to the estimator, which need redressal. Instead of directly fine-tuning the estimator itself, as is the norm, we propose the idea of 'estimating' the lopsidedness of the estimator by using it on the fully known reference model. This will enable us to effect corrections and obtain admissible estimates. Next, we explore the possibility of incorporating feedback compensation in addition to the existing cascade compensation. With output error minimization in mind, we come up with three schemes in this category. In the process, we anticipate the risk of instability due to feedback and handle it by means of an instability preventer with an inbuilt instability detector. Extensive simulations with minimum and rionminimum phase unknown plants employing the various schemes proposed are presented. A systematic study of simulation results reveals a dyad of hierarchies of progressively enhanced overall performance. One is in the sequence of the proposed schemes and the other in going for matching more and more moments. Based on our experiments we pick one of the feedback schemes as the best. Chapter 4 is conceived of as a bridge between SISO and multivariable systems. A transition from SISO to Multi-Input Multi-Output (MIMO) adaptive control is not a proposition confined to the mathematics of dimension-enhancement. A descent from the MIMO to the SISO case is expected to be relatively simple, though. So to transit as smoothly and gracefully as possible, some issues have to be placed in perspective before exploring multivariable systems. We succinctly debate on the efforts in pursuit of the exact vis-a-vis the accurate, and their implications. We then set some notations and formulate certain results which serve to unify and simplify the development in the subsequent three chapters. We list a few standard results from matrix theory which are to be of frequent use in handling multivariable systems. We derive control laws for Single-Input Multi-Output (SIMO) systems in Chapter 5. Expectedly, SIMO systems display traits of observability and uncontrollability. Results of illustrative simulations are furnished. In Chapter 6, we formulate control laws for Multi-Input Single-Output (MISO) systems. Characteristics of unobservability and controllability stand out there. We present case studies. Before actually setting foot onto MIMO systems, we venture to conjecture on what to expect there. We work out all the cascade and feedback adaptive schemes for square and nonsquare MIMO systems in Chapter 7. We show that MIMO laws when projected to MISO, SIMO and SISO cases agree with the corresponding laws in the respective cases. Thus the generality of our treatment of MIMO systems over other multivariable and scalar systems is established. We report simulations of instances depicting satisfactory performance and highlight the limitations of the schemes in tackling the family of plants of unknown upper bound on the order and possibly nonminimum phase. This forms the culmination of our exercise which took off from the reported work involving SISO systems [78]. Up to the end of the 7th chapter, we are in pursuit of solutions for the problem as general as in §1.4. For SISO systems, with input restrictions, the problem has been addressed in [79]. The laws proposed there carry out adaptation only at certain discrete instants; with respect to a suitably chosen cost, the final laws are proved to be e>optimal. In Chapter 8, aided by initial suboptimal control laws, we finally devise two algorithms with continuous-time adaptation and prove their optimality. Simulations with minimum and nonminimum phase plants reveal the effectiveness of the various laws, besides throwing light on the bootstrapping and auto-rectifying features of the algorithms. In the tail-piece, we summarize the work and wind up matters reserved for later deliberation. As we critically review the present work, we decant the take-home message. A short note on applications followed by some loud thinking as a spin-off of this report will take us to finis.

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Shankar, H. N. "Adaptive Control Of A General Class Of Finite Dimensional Stable LTI Systems." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/225.

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ARCHAMBAUD, DENIS. "Conception et realisation d'un coprocesseur simd associatif et systolique micro-programmable." Paris 6, 1995. http://www.theses.fr/1995PA066505.

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Les machines mono-processeur sont aujourd'hui devenues incapables d'effectuer certains traitements a cause des volumes de donnees qu'elles doivent traiter. Pour repondre a ce probleme, le parallelisme est une solution naturelle. Il s'est malheureusement souvent traduit par des machines tres couteuses, impliquant donc une utilisation centralisee peu pratique. Les progres en matiere d'integration vlsi permettent aujourd'hui d'obtenir des facteurs de parallelisme importants dans un seul circuit, et ainsi de concevoir des systemes paralleles peu couteux. De tels systemes peuvent etre installes comme de simples coprocesseurs dans les machines de bureau, pour offrir aux chercheurs une capacite de calcul elevee et a portee de la main. Cette these presente la realisation du coprocesseur associatif et systolique rapid-2. L'architecture se presente sous la forme d'une carte pci pouvant etre inseree dans un ordinateur hote de type pc. Pour pouvoir accelerer plusieurs familles d'applications, nous avons concu un systeme microprogrammable. Le modele de fonctionnement est simd et combine les paradigmes associatifs et systolique. La realisation de la carte est basee sur la fabrication de circuits vlsi qui seront detailles dans ce document ; ils permettent d'atteindre un parallelisme important sur une unique carte. Un facteur d'acceleration jusqu'a deux ordres de grandeur est vise, dans les domaines du traitement des textes, de la comparaison des sequences genetiques, et du traitement des images

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Chung, Kee Shik. "ILP-SIMD : an instruction parallel SIMD architecture with short-wire interconnects." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/15455.

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Spracklen, Lawrence A. "SWAR systems and communications applications." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369118.

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In recent years, the instruction sets of the majority of present day general purpose processors have been extended to include a variety of SWAR (SIMID Within A Register) instructions. These operations, which make possible the processing of multiple data elements with a single instruction, have been proven to facilitate the acceleration of a wide range of graphics and multimedia applications. The application of these instructions is not, however, just limited to this type of program, and current research is concerned with developing high performance implementations of a wide range of new applications. The initial part of this thesis presents a number of innovative strategies for accelerating previously un-addressed classes of application and illustrates that a significant degree of acceleration can frequently be achieved. However, for all of the applications analysed, several SWAR specific problems were repeatedly encountered. For the efficient operation of the implementation developed using these SWAR instructions, the organisation of the data to be processed is of critical importance and the required arrangement frequently fails to match that normally encountered in applications. SWAR ISEs (Instruction Set Extensions) usually contain functionality to address these problems, but it is shown by the author that this current functionality is insufficient and significantly curtails the performance achievable with these ISEs. The VMM (VIS Manipulation Matrix) was developed to address this problem and provide a methodology whereby the performance obtained using SWAR methodologies could be made significantly more independent of the underlying data organisation. The functionality of the VMM is presented and the effectiveness of this methodology is highlighted, by considering its application to a number of important algorithms. Finally, the feasibility of integrating the VMM into a general purpose processor is revealed, by highlighting its compatibility with the UltraSPARC processor.

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SARAIVA, SILVA IVAN. "Evaluation des performances au niveau systeme d'une architecture simd appliquee a la comparaison de sequences genetiques." Paris 6, 1995. http://www.theses.fr/1995PA066461.

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Comparaison de sequences genetiques est actuellement une activite courante en biologie moleculaire. Les comparaisons dites exactes sont, le plus souvent, executees avec des algorithmes de programmation dynamique tels que les algorithmes de needleman et wunsch ou de smith et waterman. Ces algorithmes presentant cependant une complexite theorique de l'ordre de o(m. N), ou m et n sont les tailles des sequences comparees. Cette complexite, alliee au grand volume des bases de donnees genetiques, rend impossible la realisation de comparaisons exhaustives sur des machines sequentielles classiques. Cette these presente les evaluations de performance d'une nouvelle architecture parallele, simd et systolique, appliquee a la comparaison de sequences genetiques. Cette architecture se presente sous la forme d'une carte coprocesseur montee sur un bus standard (le bus pci) pour ordinateurs du type pc ou compatibles. Pour la realisation des mesures de performances et analyses presentees dans ici nous avons developpe une version parallele de l'algorithme de smith et waterman et simule son execution sur la carte coprocesseur. Les simulations ont ete executees avec un simulateur precis, au niveau du cycle, capable de prendre en compte le temps des calculs effectues par le coprocesseur et le temps des echanges de donnees geres par l'hote. L'utilisation d'un tel simulateur nous a permis aussi de generer des vecteurs de teste pour la validation d'un modele structurel vhdl de l'architecture

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Haider, Iqbal Hasan, and MD Fazla Rabby. "Performance Analysis of Cognitive Radio Network over SIMO System." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3439.

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As resources are limited, radio spectrum becomes congested due to the growth of wireless applications. However, measurements address the fact that most of the licensed spectrums experience low utilization even in intensively teeming areas. In the exertion to improve the utilization of the limited spectrum resources, cognitive radio networks have emerged as a powerful technique to resolve this problem. There are two types of user in cognitive radio networks (CRNs) named as primary user (PU) and secondary user (SU). Therein, the CRN enables the SU to utilize the unused licensed frequency of the PU if it possibly finds the vacant spectrum or white space (known as opportunistic spectrum access). Alternatively, SU can transmit simultaneously with the PU provided that transmission power of SU does not cause any harmful interference to the PU (known as spectrum sharing systems). In this thesis work, we study fundamental knowledge of the CRNs and focus on the performance analysis of the single input multiple output (SIMO) system for spectrum sharing approach. We assume that a secondary transmitter (SU-Tx) has full channel state information (CSI). The SU-Tx can adjust its transmit power not to cause harmful interference to the PU and obtain an optimal transmit rate. In particular, we derive the closed-form expressions for the cumulative distribution function (CDF), outage probability and an analytical expression for symbol error probability (SEP). As resources are limited, radio spectrum becomes congested due to the growth of wireless applications. However, measurements address the fact that most of the licensed spectrums experience low utilization even in intensively teeming areas. In the exertion to improve the utilization of the limited spectrum resources, cognitive radio networks have emerged as a powerful technique to resolve this problem. There are two types of user in cognitive radio networks (CRNs) named as primary user (PU) and secondary user (SU). Therein, the CRN enables the SU to utilize the unused licensed frequency of the PU if it possibly finds the vacant spectrum or white space (known as opportunistic spectrum access). Alternatively, SU can transmit simultaneously with the PU provided that transmission power of SU does not cause any harmful interference to the PU (known as spectrum sharing systems). In this thesis work, we study fundamental knowledge of the CRNs and focus on the performance analysis of the single input multiple output (SIMO) system for spectrum sharing approach. We assume that a secondary transmitter (SU-Tx) has full channel state information (CSI). The SU-Tx can adjust its transmit power not to cause harmful interference to the PU and obtain an optimal transmit rate. In particular, we derive the closed-form expressions for the cumulative distribution function (CDF), outage probability and an analytical expression for symbol error probability (SEP). Iqbal Hasan Haider, cell: +46704571807 MD. Fazla Rabby, cell: +46734965477

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Misoczki, Rodolfo. "Identificação de sistemas através do método assintótico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-16032012-145350/.

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A Identificação de Sistemas é uma das técnicas utilizadas para se obter a representação matemática de um sistema. Diversos métodos podem ser aplicados para se obter um modelo matemático através da identificação de sistemas, entre eles o método de identificação assintótico, também chamado de ASYM (Zhu, 1998). Este trabalho propõe aplicar o método de identificação assintótico em sistemas SISO para a obtenção de modelo de sistemas ditos caixa-preta e avaliar o seu desempenho buscando também o melhor detalhamento do método. Os modelos obtidos foram avaliados de acordo com sua nota calculada através do método ASYM, através da comparação do índice de ajuste fit para autovalidação e validação cruzada e pela variância dos parâmetros dos modelos. O método ASYM é exaustivamente testado para sua avaliação. Entre os testes realizados neste trabalho destacam-se dois experimentos tipo Monte-Carlo com mais de quinhentas identificações e a aplicação do método em uma planta real. Os testes comprovaram a viabilidade da aplicação do método assintótico na identificação de sistemas SISO do tipo caixa-preta com excelente desempenho para estruturas ARMAX. System Identification is one of the techniques used to obtain the mathematical representation of a system. Several methods can be applied to obtain a mathematical model by the system identification, including the asymptotic method, also called ASYM (Zhu, 1998). This work proposes to apply the ASYM method for SISO systems identification, then obtain models of black-box systems called \"black box\" and evaluate its performance and show details of the method. The models obtained were evaluated according to their grade calculated using the ASYM method, by comparing the fit adjustment index, self-validation and cross validation and the variance of model parameters. The asymptotic method has been extensively tested to be evaluated. Among the tests in this work, two stand out such Monte Carlo experiments with more than five hundred identifications and a real plant identification. The tests proved the feasibility of applying the asymptotic method in the \"black box\" SISO systems identification with excellent performance for ARMAX structures.

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Mokise, Kealeboga. "Spatial diversity in a SIMO-OFDM hybrid powerline-wireless system." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/75857.

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Spatial diversity is an effective diversity technique used in multiple antenna wireless systems. It requires that antenna elements be sufficiently distributed by at least ten times the signal wavelength (10λ). Sufficient spatial distribution of antenna elements renders performance improvements through diversity gain. In consumer electronics, antenna elements are often located in close proximity, < λ, due to form size constraints. Therefore performance improvement through spatial diversity is limited even though multiple antenna systems are employed. The work in this dissertation addresses the use of power line communication as a method to spatially distribute antenna elements of a multiple antenna wireless system. Addressing this problem requires the cooperative use of both wireless and powerline channels to form a hybrid channel. A hybrid powerline-wireless channel is defined as the concatenation of a powerline channel and a wireless channel to establish a unified channel. A sequence-based channel sounding approach using maximum length sequences and software-defined radio was designed, implemented andapplied to attain channel transfer characteristics of the hybrid channel. The measurement campaign was carried out for an indoor low-voltage level powerline network. The attained results include the channel impulse responses, frequency responses and power delay profiles. Coherence bandwidth, average channel attenuation and power delay profile timing delays are channel parameters that were extracted from the measurements. The extracted channel parameters reveal that the hybrid channel is a challenging medium for data transfer and communication applications. Based on the attained hybrid channel characterisation parameters, a physical layer structure for a 1 × 2 single-input multiple-output orthogonal frequency division multiplexing (SIMOOFDM) hybrid powerline-wireless system was designed and implemented. An investigation of the bit-error-rate performance of single-carrier and multi-carrier modulation for a multipath powerline channel was carried out in simulation. Using OFDM as a suitable candidate for multi-carrier modulation, it was found to outperform single-carrier modulation. OFDM was used as the channel access method for the hybrid channel. Source encoding and decoding of the physical layer structure was designed to be robust against inherent interferences of the hybrid channel. Selection combining, equal gain combining and maximal ratio combining methods were designed and implemented. Estimation methods for error rate, data transfer rate and SNR of the SIMO-OFDM system were designed and implemented. Capacitive signal coupling was used to interface the powerline channel to the wireless propagation environment, hence establishing the hybrid channel. This method also allowed powerline transmission to be performed at a much lower frequency than wireless transmission. An experiment was conducted to investigate the effect of spatial distribution on the 1 × 2 SIMO-OFDM hybrid powerline-wireless system for indoor environments. The results of the experiment were error rate curves produced for different spatial distribution lengths through a powerline channel for each signal combining method. Error rate performance improvements in the SIMO-OFDM system were achieved with an increase of antenna element spatial distribution due to lowered signal envelope correlation. Small but yet notable diversity gains were observed by the increase in the slope of the produced error rate and signal-to-noise ratio curves for each signal combining method. Experimental parameters and apparatus placed a limitation on the achievable spatial distribution of diversity branches, hence the achievable diversity gains. This was a result of overwhelming inherent interferences of the hybrid channel Dissertation (MEng)--University of Pretoria, 2020. CeTEIS Electrical, Electronic and Computer Engineering MEng Unrestricted

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Ryu, Soojung. "Storage Management for Embedded SIMD Processors." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5122.

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SIMD parallelism offers a high performance and efficient execution approach for today's broad range of portable multimedia consumer products. However, new methods are needed to meet the complex demands of high performance, embedded systems. This research explores new storage management techniques for this focused but critical application. These techniques include memory design exploration based on the application retargeting technique, storage-based systolic instruction broadcast, and systolic virtual memory to improve both the performance and efficiency of embedded SIMD systems. For an efficient storage usage by memory design space exploration in embedded SIMD systems, an analysis method for assessing storage needs and costs of a given application automatically retargeted across a spectrum of storage configuration designs was developed. Using this technique, a SIMD processing element achieves optimal area and energy efficiency with a register file containing between 8 and 12 words for given workload. This configuration is between 15% and 25% more area and energy efficient than other memory configurations being considered. Systolic instruction broadcast is a high performance and area efficient instruction broadcasting scheme with short-wire interconnects by eliminating of wire latency bottleneck found in global instruction broadcast. Three implementation methods are defined and evaluated - software method, 2-write port register file method, and bypass method. In our evaluations, due to the system's short clock cycle time and scheduler, a speedup in system performance of up to 7.5 can be achieved by the year 2010. In addition, speedup of area efficiency also can be achieved up to 7.2 for a given workload. The ability of minimizing off-chip memory access latency while maximizing access frequency by scheduling techniques along with data prefetch techniques in systolic virtual memory mechanism was evaluated using our SIMD-systolic architecture simulator. Results show that, systolic virtual off-chip memory with shared address space can achieve over 50% higher area efficiency than that of an on-chip only system for a matrix multiplication application.

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Betz, Simon [Verfasser]. "Hesitations in Spoken Dialogue Systems / Simon Betz." Bielefeld : Universitätsbibliothek Bielefeld, 2020. http://d-nb.info/120799636X/34.

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Ben, Salem Aymen. "The Application of Multiuser Detection to Spectrally Efficient MIMO or Virtual MIMO SC-FDMA Uplinks in LTE Systems." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30351.

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Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.

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Lidbeck, Anders. "IT-system och organisationsutveckling." Thesis, Högskolan Dalarna, Informatik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:du-5056.

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This report describes work on the thesis “IT systems and organizational development”. The work is carried out on Stocksbro Energi AB, during spring 2009. The company wanted better flow in their production but also review if the inventory management function located in Visma SPCS Administration 2000, could be used in the organization. Under the first part of this report the system were tested to ensure if the system would work together with the organization. After testing the desired features they were evaluated along with two of the users to the system at the company. The wanted functions could not be obtained whenthe Admin 2000 is an economic system and are not made for the producing companies. Thereafter the theoretical possibility was examined of introducing a more advanced system to get the desired functionality to work together with the organization. To introduce a more advanced system will require major changes of the organization, before, during and after the introduction. It is therefore important how the management implements a possibility of a new system. It’s important to make the staff join in this implementation but also get as much as possible out of the system.To conclude the thesis a goal and problem analysis but also a solution proposal was made with the help of the FA/SIMM method. Also some suggestions are mentioned how the company could proceed in the implementation of the proposals for a solution.

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Levin, Matthew D. "Parallel algorithms for SIMD and MIMD computers." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/32962.

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The thesis is concerned with the inversion of matrices and the solution of linear systems and eigensystems in a parallel environment. Following an introductory chapter of concepts and definitions in the field of linear algebra, a general survey of parallel machines and algorithms is presented in Chapters 2 and 3, including a detailed description of the Distributed Array Processor (DAP) and the Neptune multiprocessing system. In Chapter 4, a new technique, the double-bordering algorithm, for the solution of linear systems is derived, and its application to the parallel solution of difference systems described. A modified form of the method for the inversion of matrices is derived, implemented on the Neptune multiprocessing system, and its performance compared with that of the Gauss-Jordan and (single) bordering algorithms. The results of the implementation of several other parallel algorithms are also presented. Chapter 5 deals with the class of matrices known as Toeplitz matrices, which arise in the field of signal processing. Trench's algorithm for the inversion of such matrices is implemented on the Neptune multiprocessing system, and, for the solution of banded symmetric Toeplitz systems, the relative efficiencies of three sequential strategies are compared: Levinson's algorithm, the double-bordering algorithm, and a method based on a novel factorisation scheme. Chapter 6 is concerned with the implementation of various iterative methods on the DAP. The solution of several difference systems by the Jacobi, Gauss-Seidel and successive over-relaxation (SOR) algorithms is compared with their solution by a variation (c. 1943) of the algorithms proposed by Hotelling, in which matrix-vector products are replaced by successive matrix squarings. The technique is also applied to the power method for the solution of the eigenvalue problem. The thesis concludes with a summary and recommendations for future work.

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Svensk, Gustav. "Bus System for Coresonic SIMT DSP." Thesis, Linköpings universitet, Datorteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129525.

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This thesis consists of designing and implementing a bus system for a specific computersystem for MediaTek Sweden AB . The focus of the report is to show the considerations andchoices made in the design of a suitable bus system. Implementation details describe howthe system is constructed. The results show that it is possible to maintain a high bandwidthin many parts of the system if an appropriate topology is chosen. If all units in a bus systemare synchronous it is difficult to reach low latency in the communication.

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Cheng, Zizhi. "Communication System over Gnu Radio and OSSIE." Thesis, University of North Texas, 2011. https://digital.library.unt.edu/ark:/67531/metadc103299/.

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GNU Radio and OSSIE (Open-Source SCA (Software communication architecture) Implementation-Embedded) are two open source software toolkits for SDR (Software Defined Radio) developments, both of them can be supported by USRP (Universal Software Radio Peripheral). In order to compare the performance of these two toolkits, an FM receiver over GNU Radio and OSSIE are tested in my thesis, test results are showed in Chapter 4 and Chapter 5. Results showed that the FM receiver over GNU Radio has better performance, due to the OSSIE is lack of synchronization between USRP interface and the modulation /demodulation components. Based on this, the SISO (Single Input Single Output) communication system over GNU Radio is designed to transmit and receive sound or image files between two USRP equipped with RFX2400 transceiver at 2.45G frequency. Now, GNU Radio and OSSIE are widely used for academic research, but the future work based on GNU Radio and OSSIE can be designed to support MIMO, sensor network, and real time users etc.

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Freudenthaler, Klemens. "Investigation of the HSDPA system and its MIMO extension /." Linz : Trauner, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=9783854994169.

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Kotze, Helen. "Systems biology of chemotherapy in hypoxia environments." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/systems-biology-of-chemotherapy-in-hypoxia-environments(4f0c4ff1-d90f-49a3-8190-94ec6ec106fa).html.

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Introduction: Hypoxia is found in solid cancerous tumours. The presence of hypoxia within tumours inhibits anti-cancer treatment strategies such as chemotherapy from being completely effective and it is suspected that multiple mechanisms contribute to the resistance. Methods: In this project a systems biology approach was applied to determine how the toxicity of doxorubicin is affected by hypoxia at the metabolome level. A multitude of analytical techniques were applied to analyse the intracellular metabolism of a monolayer of cancer cells (MDA-MB-231). Metabolic profiling was used to determine metabolite markers related to hypoxia-induced chemoresistance. For this gas chromatography mass spectrometry (GC-MS) and ultra high performance liquid chromatography mass spectrometry (UHPLC-MS) were used. Furthermore, network-based correlation analysis was developed as a novel tool to bridge the gap between metabolomics dataset and systems biology modelling. This methodology was applied to elucidate novel metabolic pathways as potential therapeutic targets to overcome hypoxia-induced chemoresistance. This algorithm determines significant correlation differences between different physiological states, and through applying graph-theory on large genome scale models; it is possible to construct a metabolic network of the pathways connecting the pair-wise correlation. Finally, imaging mass spectrometry using time-of-flight secondary ion mass spectrometry (ToF-SIMS) was developed as a tool for in situ metabolite analysis to investigate the metabolic response to chemotherapy in multi-tumour spheroids (MTSs). Results: Metabolic fingerprinting analysis characterised a snapshot of cells exposed to various environmental perturbations. Metabolite markers associated with hypoxia-induced chemoresistance were related to metabolic pathways including gluconeogenesis, DNA synthesis and fatty acid synthesis. Furthermore, network-based correlation analysis revealed specific metabolites in the fatty acid synthesis pathways were contributing to drug resistance, which included malonyl-CoA, 3-oxoeicosanoyl-CoA, stearoyl-CoA and octadecanoic acid. To facilitate the detection of metabolites in ToF SIMS datasets, a series of metabolites standard spectra were acquired. Hypoxic metabolite markers detected in ToF-SIMS data of cell lysates included glycine, lactic acid and succinic acid, which were also shown to be metabolite markers in GC-MS metabolic data. Furthermore, MTS sections were imaged using ToF-SIMS to profile the chemical response to chemotherapy treatment within the oxygen gradient. Loadings from image PCA were explored to determine the metabolic response in the highly oxygenated outer region and hypoxic inner region of the MTS. Conclusion: A multitude of analytical techniques were able to contribute to elucidating the metabolic mechanisms associated with hypoxia-induced chemoresistance. Metabolic profiling combined with a systems biology approach was further able to identify potential underlying metabolic regulation of resistance. Finally ToF-SIMS was developed as a tool for metabolite analysis in complex biological systems in situ.

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Swinford, Richard William. "An AFM-SIMS Nano Tomography Acquisition System." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3485.

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An instrument, adding the capability to measure 3D volumetric chemical composition, has been constructed by me as a member of the Sánchez Nano Laboratory. The laboratory's in situ atomic force microscope (AFM) and secondary ion mass spectrometry systems (SIMS) are functional and integrated as one instrument. The SIMS utilizes a Ga focused ion beam (FIB) combined with a quadrupole mass analyzer. The AFM is comprised of a 6-axis stage, three coarse axes and three fine. The coarse stage is used for placing the AFM tip anywhere inside a (13x13x5 mm3) (xyz) volume. Thus the tip can be moved in and out of the FIB processing region with ease. The planned range for the Z-axis piezo was 60 µm, but was reduced after it was damaged from arc events. The repaired Z-axis piezo is now operated at a smaller nominal range of 18 µm (16.7 µm after pre-loading), still quite respectable for an AFM. The noise floor of the AFM is approximately 0.4 nm Rq. The voxel size for the combined instrument is targeted at 50 nm or larger. Thus 0.4 nm of xyz uncertainty is acceptable. The instrument has been used for analyzing samples using FIB beam currents of 250 pA and 5.75 nA. Coarse tip approaches can take a long time so an abbreviated technique is employed. Because of the relatively long thro of the Z piezo, the tip can be disengaged by deactivating the servo PID. Once disengaged, it can be moved laterally out of the way of the FIB-SIMS using the coarse stage. This instrument has been used to acquire volumetric data on AlTiC using AFM tip diameters of 18.9 nm and 30.6 nm. Acquisition times are very long, requiring multiple days to acquire a 50-image stack. New features to be added include auto stigmation, auto beam shift, more software automation, etc. Longer term upgrades to include a new lower voltage Z-piezo with strain-gauge feedback and a new design to extend the life for the coarse XY nano-positioners. This AFM-SIMS instrument, as constructed, has proven to be a great proof of concept vehicle. In the future it will be used to analyze micro fossils and it will also be used as a part of an intensive teaching curriculum.

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Lopes, João Carlos Silva. "Arquitectura do vazio. Ensaio no espaço do silo de Pavia, Alentejo." Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/25795.

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Este trabalho é sobre o caso específico do silo de Pavia enquanto amostra de um património industrial obsoleto. O período que decorreu desde a sua instalação até aos dias de hoje. Propõe-se uma reflexão acerca do futuro destas estruturas e o impacto do Vazio gerado pela sua arquitectura que se impõe naquele território. Imaginar o que fora aquele lugar antes da instalação daquele aparato industrial e a sua condição actual, de ruína contemporânea. O Vazio será o tema chave para a análise que se propõe e será abordado numa escala de tempo - desde o Vazio original antes de ali existir uma construção, passando pelo Vazio contentor de armazenamento ao Vazio enquanto perda de significado que se estendeu ao conjunto de edificações de um sistema que ainda hoje persiste. É proposto um ensaio de projecto que consiste num gesto de criação de Vazio; Architecture of Emptiness: Essay in the silo space of Pavia, Alentejo. ABSTRACT: This work is about the specific case of the silo of Pavia as a sample of an obsolete industrial heritage. The period from its installation to the present. It is proposed to reflect on the future of these structures and the impact of the Void generated by their architecture that is imposed in that territory. To imagine what that place had been before the installation of that industrial apparatus and its present condition of contemporary ruin. The Void will be the key theme for the analysis that is proposed and will be approached on a time scale - from the original Void before there exists a construction, passing through the Void storage container to the Void while loss of meaning that has extended to the set of buildings of a system that still persists today. It is proposed a project essay that consists of a gesture of creation of Void.

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Andersson, Johan, Mikael Mohlin, and Artur Nilsson. "A reconfigurable SIMD architecture on-chip." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-291.

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This project targets the problems with design and implementation of Single Instruction Multiple Data (SIMD) architectures in System-on-Chip (SoC), with the goal to construct a reconfigurable framework in VHDL to ease this process. The resulting framework should be implemented on an FPGA and its usability tested. The main parts of a SIMD archi- tecture was identified to be the Control Unit (CU), the Processing Elements (PE) and the Interconnection Network (ICN), and a framework was constructed with these parts as the main building blocks. The constructed framework is reconfigurable in data width, memory size, number of PEs, topology and instruction set. To test ease of use and per- formance of the system a FIR-filter application was implemented. The scalability of the system and its different parts has been measured and comparisons are illustrated.

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Künzli, Simon [Verfasser]. "Efficient Design Space Exploration for Embedded Systems / Simon Künzli." Aachen : Shaker, 2006. http://d-nb.info/1170533213/34.

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Gulcan, Ege. "Flexible and Lightweight Cryptographic Engines for Constrained Systems." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/52913.

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There is a significant effort in building lightweight cryptographic operations, yet the proposed solutions are typically single purpose modules that can only provide a fixed functionality. However, flexibility is an important aspect of cryptographic designs where a module can perform multiple operations with different configurations. In this work, we combine flexibility with lightweight designs and propose two cryptographic engines based on the SIMON block cipher. The first proposed engine is the Flexible SIMON, which can execute all configurations of SIMON thus enables an adaptive security with variable key sizes. Our second proposed implementation is BitCryptor, a bit-serialized Compact Crypto Engine that can perform symmetric key encryption, hash computation and pseudo-random-number-generation. The implementation results on a Spartan-3 s50 FPGA show that the proposed engines occupies 90 and 95 slices respectively, which are more compact than the majority of their single purpose counterparts. Therefore, these engines are suitable cryptographic blocks for resource-constrained systems. Master of Science

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Pang, Yihan. "Leveraging Processor-diversity For Improved Performance In Heterogeneous-ISA Systems." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95299.

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The purpose of this thesis is to investigate the effectiveness of executing High Performance Computing (HPC) workloads on multiprocessors with heterogeneous Instruction Set Architecture (ISA) cores. ISA-heterogeneity in processor designs provides a unique dimension for researchers to explore performance benefits through diversity in design choices. Additionally, each application has a natural preference to one processor in a selected group of processors (we defined this term as processor-preference), and processor-preference is highly affected by processor design choices. Thus, a system with heterogeneous-ISA cores offers an intriguing design perspective, packing heterogeneous-ISA cores in the same processor or system that compensate each other in dynamic workload scenarios. This thesis considers dynamic migrating applications with different processor-preferences across ISA-different cores to exploit the potential of this idea. With SIMD instructions getting more attention from chip designers, this thesis also presents the necessary modifications for a general compiler/run-time infrastructure to transform the dynamic program state of SIMD regions at run-time from one ISA format to another for cross-ISA migration and execution. Lastly, this thesis presents a processor-preference-aware scheduling policy that makes dynamic cross-ISA migration decisions that improve overall system throughput compared to homogeneous-ISA systems. This thesis prototypes a heterogeneous-ISA system using an Intel Xeon Gold 5118 x86-64 server and a Cavium ThunderX ARMv8 server and evaluates the effectiveness of our infrastructure and scheduling policy. Our results reveal that heterogeneous-ISA systems that are processor-preference-aware and with cross-ISA execution migration capability can yield throughput gains up to 36\% compared to traditional homogeneous ISA systems. Master of Science The author of this thesis has a family full of non-engineers. To persuade family members that the work of this thesis is meaningful, aka the author is not procrastinating in school, the author decided to draw an analogy between processors and cars. Suppose in an alternative universe, cars (systems) can be powered by engines (processors) that uses two different fuel-sources (ISAs): gasoline or electric (single-ISA) processors but not both (heterogeneous-ISA). Car manufacturers (chip designers) can build engines with different design choices (processors with varying design options): engines combined with turbochargers for gasoline-powered cars, high-performance batteries combined with energy-efficient batteries for electric-powered cars (added extended instruction sets, CPU designs that target vastly different use cases, etc.). However, each design choice is limited to improving performance for a specific type of fuel-source based engine. For example, having battery alternatives has no performance impact on gasoline-powered engines. As time passes by, car manufacturers have exhausted options to make a drastic improvement to their existing engine designs (limited performance gains in recent chips). To tackle this problem, in this thesis, the author first examined the usage of cars: driving on the road (running applications). The author's study found that no single engine is suitable for all routes (no single processor is good for all workloads), and cars powered by different fuel-source based engines showed a significant diversity in performance (application performance varies drastically between systems with processors built on different ISAs). Gasoline-powered cars perform well on high-speed roads, whereas electric-powered cars perform well on low-speed roads. Unfortunately, in real life, a person's commute (a workload of applications) consists of a mixture of high-speed roads and low-speed roads, and one cannot know the exact percentage of each kind of path they travel (exact application composition in a workload) beforehand. Therefore it is challenging for a person to make the correct car selection for the incoming commute (choose the right system for a workload). This thesis tries to solve this commuting problem by building a car that has multiple engines fitted to suit different road needs (systems with processors that have vastly different use cases). This thesis looks at a particular dimension of combining various fuel-powered engines in the same car (a system with heterogeneous-ISA processors). The author believes that adding diversity in fuel-powered engine selections provide an exciting dimension in car design choices (adding ISA-heterogeneity in processors provide a unique dimension in system design). Thus, this thesis focuses on estimating a theoretical multi fuel-powered car's performance by combining two different fuel-powered cars into a single mega-car using some framework (Popcorn Linux). This framework allows this mega-car to be driven by a combined fuel source with fuel intake freely transfer between fuel-sources (cross-ISA migration and execution) based on road conditions (application encountered). Based on the evaluation of this new prototype, the author finds that in a real-life scenario (workload with mixed application combination), cars with multiple fuel-source based engines have better performance than two single fuel-source based cars (systems with heterogeneous-ISAs processors perform better than systems with homogeneous-ISAs processors). The author hopes that this study can help build the foundation for the development of hybrid cars (system with heterogeneous-ISAs in the same processor) in the future as well as the consideration of modifying existing car into a mega-car with multiple engines suited for different road needs for improved commute performance for now. Ultimately, this thesis is not about cars. The author hopes that by explaining the research done in this paper through cars, general audiences can understand what this work is trying to investigate and what solution they have provided. In this work, we investigate the potential of a system with heterogeneous-ISA processors. This thesis prototypes one such system and finds that heterogeneous-ISA systems have performance benefits than traditional homogeneous-ISA systems over a series of experiment evaluations.

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Görtzen, Simon [Verfasser]. "Performance-Guaranteed Resource Allocation in Wireless Communication Systems / Simon Görtzen." Aachen : Shaker, 2015. http://d-nb.info/106904413X/34.

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Schramm, Simon [Verfasser]. "Damping of Torsional Interaction Effects in Power Systems / Simon Schramm." München : Verlag Dr. Hut, 2010. http://d-nb.info/1008331260/34.

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Tölle, Simon [Verfasser]. "Few-Body Systems in a Shell-Model Approach / Simon Tölle." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1049984641/34.

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Schlegel, Benjamin. "Frequent itemset mining on multiprocessor systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-141763.

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Frequent itemset mining is an important building block in many data mining applications like market basket analysis, recommendation, web-mining, fraud detection, and gene expression analysis. In many of them, the datasets being mined can easily grow up to hundreds of gigabytes or even terabytes of data. Hence, efficient algorithms are required to process such large amounts of data. In recent years, there have been many frequent-itemset mining algorithms proposed, which however (1) often have high memory requirements and (2) do not exploit the large degrees of parallelism provided by modern multiprocessor systems. The high memory requirements arise mainly from inefficient data structures that have only been shown to be sufficient for small datasets. For large datasets, however, the use of these data structures force the algorithms to go out-of-core, i.e., they have to access secondary memory, which leads to serious performance degradations. Exploiting available parallelism is further required to mine large datasets because the serial performance of processors almost stopped increasing. Algorithms should therefore exploit the large number of available threads and also the other kinds of parallelism (e.g., vector instruction sets) besides thread-level parallelism. In this work, we tackle the high memory requirements of frequent itemset mining twofold: we (1) compress the datasets being mined because they must be kept in main memory during several mining invocations and (2) improve existing mining algorithms with memory-efficient data structures. For compressing the datasets, we employ efficient encodings that show a good compression performance on a wide variety of realistic datasets, i.e., the size of the datasets is reduced by up to 6.4x. The encodings can further be applied directly while loading the dataset from disk or network. Since encoding and decoding is repeatedly required for loading and mining the datasets, we reduce its costs by providing parallel encodings that achieve high throughputs for both tasks. For a memory-efficient representation of the mining algorithms’ intermediate data, we propose compact data structures and even employ explicit compression. Both methods together reduce the intermediate data’s size by up to 25x. The smaller memory requirements avoid or delay expensive out-of-core computation when large datasets are mined. For coping with the high parallelism provided by current multiprocessor systems, we identify the performance hot spots and scalability issues of existing frequent-itemset mining algorithms. The hot spots, which form basic building blocks of these algorithms, cover (1) counting the frequency of fixed-length strings, (2) building prefix trees, (3) compressing integer values, and (4) intersecting lists of sorted integer values or bitmaps. For all of them, we discuss how to exploit available parallelism and provide scalable solutions. Furthermore, almost all components of the mining algorithms must be parallelized to keep the sequential fraction of the algorithms as small as possible. We integrate the parallelized building blocks and components into three well-known mining algorithms and further analyze the impact of certain existing optimizations. Our algorithms are already single-threaded often up an order of magnitude faster than existing highly optimized algorithms and further scale almost linear on a large 32-core multiprocessor system. Although our optimizations are intended for frequent-itemset mining algorithms, they can be applied with only minor changes to algorithms that are used for mining of other types of itemsets.

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Seroka, Simon [Verfasser]. "Optimierung sequentieller optischer Systeme mit ausgedehnter Lichtquelle / Simon Seroka." Paderborn : Universitätsbibliothek, 2015. http://d-nb.info/1068255587/34.

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Simon, Marcus [Verfasser]. "Zur Stabilität dynamischer Systeme mit stochastischer Anregung / Marcus Simon." Karlsruhe : Univ.-Verl. Karlsruhe, 2004. http://d-nb.info/973243287/34.

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Allen, James D. "System level design issues for high performance SIMD architectures." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/15406.

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Lantz, Robert E. "Parallel SimOS : scalability and performance for large system simulation /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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Som, Simon E. [Verfasser]. "Bidonvilles : Development of dysfunctional urban systems in Cameroon / Simon E Som." Aachen : Shaker, 2003. http://d-nb.info/1179021967/34.

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Wollnack, Simon [Verfasser]. "Implicit Representation-Based Fixed-Structure Control of LPV Systems / Simon Wollnack." München : Verlag Dr. Hut, 2018. http://d-nb.info/1164293966/34.

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Muzzulini, Marco. "Titchmarsh-Sims-Weyl theory for complex Hamiltonian systems of arbitrary order." [S.l. : s.n.], 2007. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000007403.

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Arvidsson, Lars. "Stereoseende i realtid." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10236.

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In this thesis, two real-time stereo methods have been implemented and evaluated. The first one is based on blockmatching and the second one is based on local phase. The goal was to be able to run the algorithms at real-time and examine which one is best. The blockmatching method performed better than the phase based method, both in speed and accuracy. SIMD operations (Single Instruction Multiple Data) have been used in the processor giving a speed boost by a factor of two. I det här exjobbet har två stereometoder för realtidstillämpningar implementerats och utvärderats. Den ena bygger på blockmatchning och den andra på lokal fas. Målet var att kunna köra metoderna i realtid och undersöka vilken av dem som fungerar bäst. Blockmatchningsmetoden gav gott resultat medan den fasbaserade fungerade sämre, både vad gäller hastighet och precision. SIMD-operationer (Single Instruction Multiple Data) användes hos processorn vilket resulterade en i fördubbling av prestandan.

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Verleger, Simon [Verfasser]. "Transportphänomene in nano- und mikroskopischen Systemen / Simon Verleger." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/102190256X/34.

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Malone, MaryLauren. "Simon Says: Response Dynamics to Meaningful Joint Action Gestures." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1382372693.

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Teeuwsen, Simon P. [Verfasser]. "Oscillatory Stability Assessment of Power Systems using Computational Intelligence / Simon P Teeuwsen." Aachen : Shaker, 2005. http://d-nb.info/1186581786/34.

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Schliecker, Simon [Verfasser]. "Performance analysis of multiprocessor real-time systems with shared resources / Simon Schliecker." Braunschweig : Institut für Datentechnik und Kommunikationsnetze, 2011. http://d-nb.info/1231994363/34.

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Hughes, Ruby Wai Chung. "SIMT : a holistic framework for embedding simulation into the health care systems." Thesis, Sheffield Hallam University, 2010. http://shura.shu.ac.uk/19844/.

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Simulation and Modelling (S&M) have been proven as very valuable tools in the health care sector. In recent years, the sector has experienced a rapid increase in applications. However, it appears that health care organisations have failed to sustain the use of these powerful techniques. In this research, an extensive literature review is carried out to identify the main challenges of the use of health care simulation and the underlying barriers of implementing S&M in the sector. In order to address these issues, it identifies the need to fully embed S&M into the sector through a systematic approach. However, the literature in this subject area has not provided such a holistic approach to the use of simulation. With the view to embed these techniques in health care decision making processes, this research develops a new framework, known as SIMulation Thinking (SIMT), to overcome the identified challenges and barriers. SIMT includes five key components: infrastructure, management, culture change, methodology and modelling. Whilst the SIMT framework presents the important elements that need to be considered to make S&M mainstream tools, this research also presents an implementation framework which transforms SIMT into a practical and applicable approach to embed S&M in health care organisations. The implementation framework includes two main stages: planning stage and action stage. Questionnaire and case study approach are conducted to validate the usefulness and importance of the SIMT components and the proposed implementation framework. The questionnaire is used to understand how the selected group of experts consider the SIMT components and the planning stage of the implementation framework as a valuable guideline. To validate the action stage of the implementation framework, this research uses the case study approach which introduces the proposed methodologies and modelling best practices into a local hospital. The feedback received from the hospital is used to evaluate the usefulness and practicable of the proposed approach.

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