Dissertations / Theses: 'Multiple'

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Yilmaz, Mehmet. "Multiple Target Tracking Using Multiple Cameras." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12609477/index.pdf.

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Video surveillance has long been in use to monitor security sensitive areas such as banks, department stores, crowded public places and borders. The rise in computer speed, availability of cheap large-capacity storage devices and high speed network infrastructure enabled the way for cheaper, multi sensor video surveillance systems. In this thesis, the problem of tracking multiple targets with multiple cameras has been discussed. Cameras have been located so that they have overlapping fields of vision. A dynamic background-modeling algorithm is described for segmenting moving objects from the background, which is capable of adapting to dynamic scene changes and periodic motion, such as illumination change and swaying of trees. After segmentation of foreground scene, the objects to be tracked have been acquired by morphological operations and connected component analysis. For the purpose of tracking the moving objects, an active contour model (snakes) is one of the approaches, in addition to a Kalman tracker. As the main tracking algorithm, a rule based tracker has been developed first for a single camera, and then extended to multiple cameras. Results of used and proposed methods are given in detail.

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Turker, Burcu. "Multiple hypothesis tracking for multiple visual targets." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611837/index.pdf.

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Visual target tracking problem consists of two topics: Obtaining targets from camera measurements and target tracking. Even though it has been studied for more than 30 years, there are still some problems not completely solved. Especially in the case of multiple targets, association of measurements to targets, creation of new targets and deletion of old ones are among those. What is more, it is very important to deal with the occlusion and crossing targets problems suitably. We believe that a slightly modified version of multiple hypothesis tracking can successfully deal with most of the aforementioned problems with sufficient success. Distance, track size, track color, gate size and track history are used as parameters to evaluate the hypotheses generated for measurement to track association problem whereas size and color are used as parameters for occlusion problem. The overall tracker has been fine tuned over some scenarios and it has been observed that it performs well over the testing scenarios as well. Furthermore the performance of the tracker is analyzed according to those parameters in both association and occlusion handling situations.

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Bunn, J. J. "Multiple narratives, multiple views : observing archival description." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1322455/.

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This thesis takes a grounded theory approach in an attempt to seek, articulate and communicate a deeper understanding of the practice known as archival description. In so doing, it also seeks to allow readers to experience for themselves the process through which this thesis took shape, the research journey through which emerged both the questions and the answers. A more detailed exposition of the stages within this process is given in chapter three, which thereby acts as one route map to the whole. Another such map is provided here, in the following brief summary. Undertaking this journey, the questions that emerged included; what does autonomy mean, how is it possible to communicate, to bridge the gap between the separateness of individuals, and ultimately, how is it possible to have separateness without being separate? Then again, the answers that evolved concurrently seemed to lie in using a cybernetic perspective, and employing the concept of autopoiesis or self-production, whereby it is thought possible to become separate without being so. Further, as a result of the questions and answers explored above, a thesis took shape, that practicing archival description is a point of view, one from which it is difficult to lose sight of the observing within the observation, that is to say it is a point of view about how we look at the world and form a point of view in respect of it, about how we know what we know. It is this thesis which will be laid out in later chapters of this work, but first will follow introductions to both the substantive area of interest (archival description) and the approach taken (grounded theory).

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Kanday, Balaji Madapuci. "Microcontroller Based Multiple-Input Multiple-Output Transmitter." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605952.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
This paper describes how a microcontroller based system can be used to generate the signals needed in a multiple-input multiple-output (MIMO) system transmitter. The limited computational speed of the microcontroller, along with other tasks which the controller may need to handle, places limits on the throughput of the system, and the complexity of the MIMO signal design. However this can be a low cost design, and the microcontroller can be used to perform other operations in the system, which may make it attractive in some applications.

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Tran, Tuan-Anh. "Multiple-input multiple-output optical wireless communications." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:094fbe23-88c3-49c4-b64b-a1de40674123.

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Visible-light optical wireless communications (OWC) is a potential technology that can help resolve the crowdedness of the radio-frequency bands, whilst conveniently exploiting energy-saving light-emitting diodes (LEDs) as transmitters for both illumination and communications. Since there usually are many LEDs in a lighting unit, OWC has a multi- input multi-output (MIMO) geometry which, thanks to its channel diversity, can offer wireless local networks at data-rates many times higher than possible with single-channel systems. In such systems, MIMO-detection methods to separate the different optical channels play an important role in improving the system performance by helping reduce cross-talk between channels. To measure the performance of a particular geometry for MIMO communications, a simulation study, reported in this thesis, found that, amongst the signal- independent metrics, the condition number may be used as a rough predictor of the performance, whilst the channel Signal-to-Interference-and-Noise Ratio (SINR) is the most appropriate for geometry assessment. Combined with the fact that the overall performance of a MIMO system is mostly dominated by its worst channel, this indicates that the most effective way to improve the system performance is to maximise the worst channel’s SINR. One of the possible solutions to improving the SINRs is to use holograms to steer the transmitter images such that their distributions over the photo-detectors reduce overlaps. As LEDs emit partially-coherent light, the beam steering has to be carried out with partially- coherent illumination. By using two lenses to parallelise and collect partially-coherent light before and after the hologram, respectively, the source and image intensity distributions, and the autocorrelation of the hologram can be related in a succinct mathematical relationship. This leads to the development of three computational algorithms based on the autocorrelation function to obtain a quantised hologram with the desired beam-steering capability. These algorithms have their cost functions and performance comparison done at the hologram plane instead of the image plane, which therefore takes less time than traditional image-based methods. Specifically, one of these algorithms is able to save significant time over both the other autocorrelation-based algorithms and the direct binary-search, by 33% and by 50% respectively. A simulation-based study and a corresponding experiment, both reported in this thesis, found that the one of the proposed algorithms had poor power efficiency, whilst the other two were both highly effective in generating digital holograms with precise and power-efficient beam-steering performance. Of these two algorithms, one had superior time performance and was likely the best of the three proposed autocorrelation-based algorithms for generating beam-steering holograms. MIMO-OWC simulation also demonstrated the capability of using beam-steering holograms to design the channel and improve the system performance. Combining reported findings, a strategy can be devised to optimise the throughput of an imaging MIMO-OWC system for a given transmitted power.

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MATSUMOTO, Kohji, and Hirofumi TSUMURA. "Generalized multiple Dirichlet series and generalized multiple polylogarithms." Institute of Mathematics Polish Academy of Sciences, 2006. http://hdl.handle.net/2237/9366.

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Gruneir, Bram. "Multiple Agent Architecture for a Multiple Robot System." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/792.

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Controlling systems with multiple robots is quickly becoming the next large hurdle that must be overcome for groups of robots to successfully function as a team. An agent oriented approach for this problem is presented in this thesis. By using an agent oriented method, the robots can act independently yet still work together. To be able to establish communities of robots, a basic agent oriented control system for each robot must first be implemented. This thesis introduces a novel method to create Physical Robot Agents, promoting a separation of cognitive and reactive behaviours into a two layer system. These layers are further abstracted into key subsections that are required for the Physical Robot Agents to function. To test this architecture, experiments are performed with physical robots to determine the feasibility of this approach.

A real-time implementation of a Physical Robot Agent would greatly expand its field of use. The speed of internal communication is analyzed to validate the application of this architecture to real-time tasks.

It is concluded that the Physical Robot Agents are well suited for multiple robot systems and that real-time applications are feasible.

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Ahmady, Ali. "Rough set Kansei engineering: multiple users, multiple Kanseis." Diss., Wichita State University, 2010. http://hdl.handle.net/10057/3638.

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The method proposed in this dissertation addresses the need to relate product features to customer expectations. This is particularly difficult given the variety of consumer perspectives and the uncertainty in their assessments. Current statistical methods may not relate all of the market research information available to customer-oriented product-development approaches. Rough set-based Kansei Engineering (RSBKE) is an approach for reasoning under uncertainty and deals with imperfect information originating from the imprecision of human assessment. This mathematically powerful approach extracts knowledge from customer survey data and develops product design rules based upon single or multiple subjective impressions (Kansei) from single or multiple users. A two-stage user-oriented product development approach generates market segmentation rules and product design rules for either a single or multiple Kansei(s). RSBKE provides an enhanced means of defining primary customer groupings and automatically generating design rules. Several extensions to target marketing, lead-user identification, and Kano model applications are presented. RSBKE can be extended to the decision attributes of functional customer requirements. The approach presented here is compared to statistical methods. A case study involving a website design was used to illustrate this approach. The results identified distinctive classes of users who had the same perception of a set of websites. The system generated a set of strict design rules for each class.
Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering

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Petersen, Samuel. "Multiple-Input Multiple-Output Systems for Spinning Vehicles." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605956.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
This paper investigates the performance of a multiple-input multiple-output (MIMO) digital communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rayleigh plus line-of-sight, or Rician, models combined with a deterministic model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas, modulates the signal, and complicates the decoding and channel parameter estimation processes. The simulated system bit error rate is the primary performance metric used. The Alamouti channel code is shown to perform better than the maximal ratio receiver combining (MRRC) and single receiver (2x1) system in some circumstances and performs similarly to the MRRC in the broadside case.

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Harris, Kevin E. "Multiple Channel, Multiple Data Type, Rugged 8mm Recorder." International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/611873.

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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Low cost recording devices for telemetry and other data acquisition applications are of vital importance in light of today's shrinking budgets and project cut-backs. The desire to replace large, expensive, multi-channel recorders with smaller, less expensive recorders is becoming commonplace in government and industry. Many of these small recorders in the past have been limited to a single recording channel, and to one particular data type, due to recorder architectures. The 8 millimeter (8mm) tape cartridge recorder has been looked at in the past as a low cost recording device, however products utilizing this technology have been strictly limited in the number of channels, and data types. In response to this need, Veda has developed a new data acquisition recorder utilizing an 8mm recorder packaged in a small, flight qualified rugged enclosure with modular, and interchangeable, input channels. These microprocessor controlled inputs are capable of accepting PCM telemetry, MIL-STD-1553, voice, IRIG time, and ARINC 429/629 data. The new architecture allows for multiplexing of multiple channels onto the single channel tape medium as well as direct playback from the recorder for certain data types. This paper will discuss the recorder's architecture, design problems solved during development, and general capabilities.

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Zhang, Peichang. "Coherent versus differential multiple-input multiple-output systems." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/376511/.

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In recent years, Multiple-Input-Multiple-Output (MIMO) techniques have attracted substantial attention due to their capability of providing spatial diversity and/or multiplexing gains. Inspired by the concept of Spatial Modulation (SM), the novel concept of Space-Time-Shift-Keying (STSK) was recently proposed, which is considered to have the following advantages: 1) STSK constitutes a generalized shift keying architecture, which is capable of striking the required trade-off between the required spatial and time diversity as well as multiplexing gain and includes SM and Space Shift Keying (SSK) as its special cases. 2) Its high degree of design-freedom, the above-mentioned flexible diversity versus multiplexing gain trade-off can be achieved by optimizing both the number and size of the dispersion matrices, as well as the number of transmit and receive antennas. 3) Similar to the SM/SSK schemes, the Inter-Antenna-Interference (IAI) may be eliminated and consequently, the adoption of single-antenna-based Maximum Likelihood (ML) detection becomes realistic in STSK schemes. In this report, our investigation can be classified into two major categories, Coherent STSK (CSTSK) and Differential STSK (DSTSK) schemes. For CSTSK, since Channel State Information (CSI) is required for data detection, Channel Estimation (CE) techniques become necessary. To be more explicit, we first briefly review the conventional Training Based CE (TBCE) and Semi-Blind CE (SBCE) schemes for the CSTSK MIMO schemes. In addition, we develop a Blockof-Bits Selection Based CE (BBSBCE) algorithm for CSTSK schemes for increasing the overall system’s throughput, while improving the accuracy of the CE. Additionally, it has been widely recognised that MIMO schemes are capable of achieving a diversity and/or multiplexing gain by employing multiple Antenna Elements (AEs) at the transmitter and/or the receiver. However, it should also noted that since MIMO systems utilize multiple RF chains, their power consumption and hardware costs become substantial. Against this background, we introduce the concept of (Antenna Selection) AS and propose a simple yet efficient AS algorithm, namely the Norm-Based Joint Transmit and Receive AS (NBJTRAS) for assisting MIMO systems. For DSTSK, since no CSI is required for differential detection schemes, it also draws our attention. However, in the absence of CE, the Conventional Differential Detection (CDD) schemes usually suffer from a 3 dB performance degradation and may exhibit an error-flow when Doppler frequency is excessive. In order to mitigate this problem, we investigate Multiple-Symbol Differential Sphere Detection (MSDSD) scheme and adopt it in our DSTSK scheme to improve the system performance, while reducing the detection complexity. Furthermore, based on our MSDSD detected DSTSK scheme, we propose a DSTSK aided Multi-User Successive Relaying aided Cooperative System (MUSRC), which is capable of supporting various number of users flexibly, while covering the conventional 50% throughput loss due to the half-duplex transmit and receive constraint of practical transceivers.

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Acree, Elizabeth Ann 1960. "The community college counselor: Multiple meanings, multiple realities." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282789.

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Counselors are currently being scrutinized as to their place in a community college setting. Administrative units are questioning whether counselors are necessary, and whether they should maintain their past role. But before changes are made, the full scope of the role needs to be examined. Previous studies have concentrated on role definition, looking primarily at which tasks counselors perform and their job satisfaction. I first examine the counselor's role using a role definition format to provide a baseline of data to compare with other studies. Then I considered three other elements--intangible services, professionalization, and the bureaucratic setting--that I proposed were contributing to the uncertain position of counselors in community colleges. This is a qualitative case study of community college counselors. Personal interviews with counselors were utilized as the primary source of data. The case study institution is a large, urban, multi-campus community college. Results indicate that counselors are satisfied with their generalist role of providing primarily career and academic counseling, providing a very small percentage of personal counseling and providing a variety of other services. This is unlike the literature which suggests that counselors are dissatisfied with the generalist role and prefer a more specialized personal counseling role. The counselors in this study were frustrated by their perceived role by other groups. They felt misunderstood and unappreciated. Consequently, they searched for ways to make their services more visible and understandable. They also relied heavily on their professional status to validate their role. But rather than emphasizing their traditional professional counseling characteristics like the use of a theoretical body of knowledge or specialized training and certification, they underscored their similarity to the instructional faculty who command the highest professional status in community colleges. The counselor's role was also highly effected by bureaucratization. The very nature of bureaucracies induces human interaction that is brief and efficient, but not necessarily meaningful. Improving human interaction is where counselors need to focus their efforts, rather than dwelling on professional status. And, administrators must also consider human interaction rather than just dividing tasks and measuring the number of students served.

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Evanshen, Pamela. "Multiple Intelligences." Digital Commons @ East Tennessee State University, 2004. https://dc.etsu.edu/etsu-works/4418.

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Shanmugam, Pravinkumar. "Multiple-user multiple-input multiple-output beam-forming and frequency reuse in millimeter wave communication." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1603753.

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This paper explains a new beam-forming technique implemented in a deterministic Multiple-Input Multiple-Output (MIMO) channel model in 60 GHz millimeter wave frequency. We calculate path loss between the transmitter and receiver antenna elements in the line of sight path. Assuming that Channel State Information (CSI) is known as the deterministic values at the transmitter, the Composite Transfer Function (CTF) derived from the CSI generates orthogonal beams. The orthogonal beam allows us to reuse the frequency at the same time slot with the capability of multi-user MIMO. Our beam forming technique controls the radiated power at the transmitter in such a way that the power received at a particular receiving antenna element is 0dB, and it is suppressed to less than -60dB at other receiving elements. We study the performance of our proposed beam-forming technique by transmitting the QPSK modulated signal through the orthogonal beams, and analyzing the bit error rate curve.

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Li, Yikai. "Non-Orthogonal Multiple Access for Massive Multiple-Input Multiple-Output Relay-Aided/Cell-Free Networks." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/dissertations/1906.

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The recent developments in Internet-of-Things (IoT) and the next-generation wireless communication systems (5G and beyond) are posing unprecedented demands for massive connectivity, enhanced spectrum efficiency, and strengthened reliability. Moreover, the conventional orthogonal multiple access (OMA) techniques have approached their fundamental limits or the improvements in performance are marginal. To this end, a paradigm-shift from OMA to massive multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) technology is proposed. The proposed techniques are capable of serving multiple spatially-distributed user nodes/IoTs in the same frequency-time resource block by reaping out the benefits of power-domain NOMA, and favorable propagation and channel hardening brought by very large antenna arrays.First, a comprehensively literature survey has been conducted. Next, system, channel and signal models were developed by considering practical transmission impairments of the proposed massive MIMO NOMA. Then, novel NOMA relaying strategies via massive MIMO with pilot designs, per-hop and cascaded channel estimation, statistical-parameter based power allocation policy, and reliable precoding scheme are designed. Then, a complete analytical framework to derive the fundamental performance metrics is developed. A MATLAB-based simulation framework is developed to verify the proposed system designs.Then, the detrimental effects of residual interference caused by intra-cluster pilot sharing and error propagation caused by imperfect successive interference cancellation are quantified. The results acquired can provide insights for refining the proposed techniques in terms of signal model and pilot design.Trade-offs among massive connectivity and spectral efficiency will be established and refined for the proposed relay aided/cell-free massive MIMO NOMA via carefully designing per-hop and cascaded channel estimation, low-complexity statistical-parameter-based power allocation, and conjugate precoding schemes. The proposed technique is expected to significantly outperform the conventional OMA scheme in all overloaded system scenarios by virtue of the proposed aggressive spatial multiplexing and power-domain NOMA techniques. Hence, the proposed technique can simultaneously serve many users with fast data rates than that of the existing OMA techniques. The proposed NOMA techniques are expected to provide higher spectral and energy efficiencies with ultra-low end-to-end latency than those of existing OMA. Thus, the proposed relay-aided/cell-free massive MIMO NOMA can significantly contribute as a novel candidate technology for the next-generation wireless standards.

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Nobilet, Jean-Michel. "Systèmes MIMO (" Multiple Input Multiple Output ") à porteuses multiples :Etude et optimisation de la combinaison de codes temps-espace et des techniques MC-CDMA (" Multi-carrier code division multiple access ")." Rennes, INSA, 2004. http://www.theses.fr/2004ISAR0006.

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Dans la recherche de modulations adaptées à la voie descendante des systèmes cellulaires 4G, les systèmes MC-CDMA s'affirment comme des solutions à fort potentiel. En parallèle, les systèmes MIMO constituent une nouvelle voie très prometteuse améliorant notablement l'efficacité spectrale des systèmes hertziens via la dimension spatiale. Cette thèse porte sur l'optimisation de systèmes MIMO/MCCDMA par l'étude des codes temps-espace en blocs ou en treillis. Après un état de l'art, nous proposons de nouveaux codes STBC orthogonaux, puis une représentation des STTC basée sur une notation polynômiale permettant la comparaison des codes existants. La combinaison STBC/MC-CDMA étudiée améliore sensiblement les performances d'un système MC-CDMA SISO avec un décodage peu complexe. Leur optimisation repose sur des techniques de détection mono-utilisateurs ou multi-utilisateurs. Leur performances sont évaluées sur des canaux théoriques ou réalistes. Enfin, la combinaison STTC/MC-CDMA est étudiée
In the context of the research of new modulation schemes for the downlink of the 4th Generation mobile radio systems, the MC-CDMA schemes are the most promising candidates. On the other hand, MIMO systems inherit space diversity to mitigate fading effects and improve dramatically the spectrum efficiency. This thesis deals with the optimisation of MIMO/MC-CDMA systems through the use of space-time block coding or trellis coding. We propose new orthogonal STBC and a new representation of STTC based on a polynomial notation. The studied STBC/MC-CDMA systems improve the performance of a MC-CDMA SISO system with a low complex decoding. Their optimisation is based on single-user and multiple-user detection schemes. Their performance are evaluated on theoretical and realistic channels. Finally, the STTC/MC-CDMA is studied

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Uppal, Momin Ayub. "Code design for multiple-input multiple-output broadcast channels." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1783.

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Yu, Kai. "Modeling of Multiple-Input Multiple-Output Radio Propagation Channels." Licentiate thesis, KTH, Signals, Sensors and Systems, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1478.

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In recent years, multiple-input multiple-output (MIMO)systems appear to be very promising since they can provide highdata rates in environments with sucient scattering byexploiting the spatial domain. To design a real MIMO wirelesssystem and predict its performance under certain circumstances,it is necessary to have accurate MIMO wireless channel modelsfor dierent scenarios. This thesis presents dierent models forindoor MIMO radio propagation channels based on 5.2 GHz indoorMIMO channel measurements.The recent research on MIMO radio channel modeling isbriey reviewed in this thesis. The models are categorized intonon-physical and physical models. The non-physical modelsprimarily rely on the statistical characteristics of MIMOchannels obtained from the measured data while the physicalmodels describe the MIMO channel (or its distribution) via somephysical parameters. The relationships between dierent modelsare also discussed.For the narrowband case, a non line-of-sight (NLOS)indoor MIMO channel model is presented. The model is based on aKronecker structure of the channel covariance matrix and thefact that the channel is complex Gaussian. It is extended tothe line-of-sight (LOS) scenario by estimating and modeling thedominant component separately.As for the wideband case, two NLOS MIMO channel modelsare proposed. The rst model uses the power delay prole and theKronecker structure of the second order moments of each channeltap to model the wideband MIMO channel while the second modelcombines a simple single-input single-output (SISO) model withthe same Kronecker structure of the second order moments.Monte-Carlo simulations are used to generate indoor MIMOchannel realizations according to the above models. The resultsare compared with the measured data and good agreement has beenobserved.

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Tajima, May. "Modelling multiple criteria-multiple participant problems, the integrative approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0009/NQ30653.pdf.

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Reimer, Donald A. "Multiple staff ministry in multiple point parishes of Manitoba." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0019/NQ46683.pdf.

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Lu, Di. "Antenna selection schemes for multiple-input multiple out systems." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493529.

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Theoretical research show that wireless communication systems using multiple-input multiple-output (MIMO) antennas can provide a very high spectral efficiency in rich scattering environments. This thesis investigates issues of antenna selection in MIMO systems with an emphasis on the criteria and algorithms of receive antenna selection in layered spatial multiplexing architectures.

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Dambul, Katrina D. "Multiple-input multiple-output (MIMO) in optical wireless communications." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558676.

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There is growing demand for indoor wireless communication systems with higher bandwidth and higher data rates. However, the crowded radio frequency (RF) spectrum has caused researchers to consider optical wireless systems. In this thesis, optical signals in the visible region of the spectrum are used. White LEDs are used as transmitters as they provide higher signal-to-noise (SNR) levels and a better link budget than the infrared alternative. Typical modulation bandwidths for white LEDs are limited to tens of MHz. Thus, multiple-input multiple-output (MIMO) transmission is considered as a means to increase data rate. The development of the indoor optical wireless MIMO system begins with the geometrical and mathematical analysis of a single-input single-output (SISO) system and a single-input multiple- output (SIMO) system. The same analysis is then performed for a MIMO system. For the MIMO system, an experimental demonstration using white LEDs and non-imaging receivers are reported. Results include coverage measurements and an SNR analysis. There are limitations using non- imaging receivers, such as coverage limitations and symmetry problems, which cause problem with signal recovery. To improve these limitations, imaging receivers are considered. The design and development of an experimental demonstration of an indoor optical wireless MIMO system with an imaging receiver is presented. The experimental setup consists of a transmitter with a 2 x 2 array of white LEDs and a receiver with a 3 x 3 photo detector array. The system transmits data at a bit rate of 2Mbit/s/channel. Detailed design specifications and optical design are presented. Results show that certain positions within the system coverage area have error-free operation. The BER and SNR analysis shows that the overall BER improves with the overall SNR. In order to exploit the full potential of the system, future work should focus on improving the SNR and BER of the system.

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Gupte, Abhishek. "SOQPSK Signals in Multiple Input Multiple Output (MIMO) Systems." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605954.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
This paper investigates the use of shaped offset quadrature phase shift keying (SOQPSK) signals in multiple-input multiple-output (MIMO) communication systems. The goal is to integrate commonly used receiver architectures for conventional single-input single-output (SISO) systems into a corresponding MIMO system. The benefits of improved spectral efficiency are juxtaposed against the increased receiver complexity. Bit error rate performances for the SISO and MIMO architectures in a multipath environment are compared and conclusions regarding trade-offs between signal to noise ratio (SNR) and spectral efficiency stated.

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Seward, Lori Welte. "A multiple stress, multiple component stress screening cost model." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/41578.

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Environmental stress screening is used to enhance reliability by decreasing the number of failures experienced during customer use. It is suggested that added benefit can be gained by applying multiple stresses rather than a single stress, as is done presently. A further modification is to apply the stress at the assembly level, accelerating different types of components at the same time. Different component E A e acceleration effects must then be considered.

The problem these modifications present is how to choose the appropriate stress levels and the time duration of the stress screen. A cost model is developed that trades off the cost of a field failure with the cost of applying a multiple stress, multiple component stress screen. The objective is to minimize this cost function in order to find an economical stress regimen.

The problem is solved using the software package GINO. The interesting result is that if a stress is used at all during the stress screen, the maximum amount of stress is the economic choice. Either the cost of stressing is low enough to justify the use of a stress, in which case the maximum amount of stress is used, or the cost is too high and the stress is not used at all.

Master of Science

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Dogutas, Aysun. "School Violence in Turkey, Multiple Perspectives in Multiple Settings." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1310504543.

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Stewart, Kyle Bradley. "Waveform-Diverse Multiple-Input Multiple-Output Radar Imaging Measurements." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1450437383.

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Najam, Ali Imran. "Multiple-input multiple-output antennas for ultra wideband communications." Grenoble INPG, 2010. http://www.theses.fr/2010INPG0043.

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La radio Ultra Large Bande (ULB) promet de nouveaux marchés dans les domaines des réseaux personnels hauts débits et de capteurs. De sorte à améliorer la robustesse du lien radio et le débit, l’association des techniques MIMO à l’ULB a été envisagée. En vue d’une réalisation pratique, un challenge fondamental reste la conception des antennes qui doivent répondre aux contraintes de l’ULB et des systèmes multi-antennaires, et aux contraintes physiques et économiques. Dans ce contexte, plusieurs nouveaux designs d’antennes MIMO ULB sont proposés. Leur caractérisation s’appuie sur les paramètres conventionnels utilisés en conception d’antennes ainsi que des paramètres spécifiques à l’ULB et au MIMO. En particulier, un nouveau design compact présentant une forte isolation grâce à l’insertion d’un stub sur le plan de masse est proposé. Une nouvelle méthode de modélisation du couplage mutuel, qui présente l’avantage d’offrir de nouvelles approches pour le compenser, est également introduite
UWB technology has rapidly emerged in the areas of WPAN and sensors networks featuring high data rate communications. The applications of UWB are limited to very short-range communications due to the extremely low transmitted power. The combination of MIMO techniques with UWB has been considered as a solution to improve the range. However, a fundamental challenge arises for the design of antennas that faces the constraints offered by UWB systems and multi-antennas systems, and the constraints of size and cost. In this context, several new UWB-MIMO antennas are proposed. Their characterization is based on the parameters relevant to conventional antenna design and the specific parameters relevant to the UWB-MIMO antenna design. In particular, a new compact design with high isolation by inserting the inverted-Y shaped stub on the ground plane is proposed. A new method for modelling the mutual coupling, is also introduced which has the advantage of offering new approach to compensate it

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Trujillo, Castañeda Eduardo Daniel. "Resource allocation for multiple-user multiple-antenna cellular systems." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14078.

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Doutoramento em Engenharia Electrotécnica
The thesis addresses the sum rate or spectral e ciency maximization problem in cellular systems with two main components, multiple antennas and multiple users. In order to solve such a problem, several resource allocation techniques are studied and developed for di erent cellular scenarios. The antennas at the transmitters are arranged in several con gurations, i.e., co-located or distributed and for such arrangements di erent levels of coordination and cooperation between transmitters are investigated. Accounting for more receiver antennas than transmitter antennas implies that system optimization must select the best transmitter-receiver match (combinatorial problem) which can be solved with di erent degrees of cooperation between transmitters. The system models studied can be classi ed either as interference limited or as power limited systems. In interference limited systems the resource allocation is carried out independently by each transmitter which yield power leakage to unintended receivers. For this kind of systems, the access network using distributed antenna architectures is examined. The properties of distributed antenna in cellular systems as well as the gains they provide in terms of frequency reuse and throughput are assessed. Accounting for multiple user scenarios, several techniques and algorithms for transmitter-receiver assignment, power allocation, and rate allocation are developed in order to maximize the spectral e ciency. In power limited systems the transmitters jointly allocate resources among transmit and receive antennas. The transmitters are equipped with multiple antennas and signal processing is implemented in order to suppress inter-user interference. Single-cell and multi-cell systems are studied and the problem of sum rate maximization is tackled by decoupling the user selection and the resource allocation (power and precoding) processes. The user selection is a function of the type of precoding technique that is implemented and the level of information that can be processed at the transmitter. The developed user selection algorithms exploit information provided by novel channel metrics which establish the spatial compatibility between users. Each metric provides a di erent trade-o between the accuracy to identify compatible users, and the complexity required to compute it. Numerical simulations are used to assess the performance of the proposed user selection techniques (metrics and algorithms) whose performance are compared to state-of-the-art techniques.
Esta tese descreve o problema da maximização da taxa de transmissão ou e ciência espectral em sistemas moveis tomando em atenção duas características fundamentais destes, o número de antenas e utilizadores. A fim de resolver este tipo de problema, várias técnicas de alocação de recursos foram estudadas e propostas para diferentes cenários. As antenas nos transmissores estão organizadas em diferentes configurações, podendo ser localizadas ou distribuídas e para estes esquemas, diferentes níveis de cooperação e coordenação entre transmissores foram investigados. Assumindo mais antenas receptoras do que antenas transmissoras, implica que a otimização do sistema seleccione as melhores combinações de transmissor-receptor (problema combinatório), o que pode ser concretizado usando diferentes graus de cooperação entre transmissores. Os modelos de sistemas estudados, podem ser classificados como sistemas limitados por interferência ou sistemas limitados por potência. Em sistemas limitados por interferência a alocação de recursos e feita independentemente para cada transmissor o que resulta em perda de energia para os receptores não tomados em consideração. Para este tipo de sistemas, e considerado o caso em que a rede de acesso e constituída por antenas distribuídas. Os ganhos obtidos devido ao uso de antenas distribuídas, quer em termos do planeamento de frequências quer da maximização da taxa de transmissão são considerados. Assumindo esquemas multi-utilizador, várias técnicas e algoritmos de transmissão-recepção, alocação de potência e de taxa de transmissão foram desenvolvidos para maximizar a e ciência espectral. Para sistemas limitados em potência os transmissores alocam os recursos quer de antenas de transmissão quer de recepção conjuntamente. Os transmissores estão equipados com várias antenas e o processamento de sinal e implementado de modo a eliminar a interferência entre utilizadores. Sistemas de célula única e de múltiplas células foram estudados. Para estes foi considerado o problema da maximização de taxa de transmissão o qual foi resolvido heuristicamente, através do desacoplamento do problema em duas partes, uma onde se efectua a seleção de utilizadores e outra onde se considera a alocação de recursos. A seleção de utilizadores e feita em função do tipo de técnicas de pré-codificação implementadas e do nível de informação que o transmissor possui. Os algoritmos de seleção de utilizadores desenvolvidos verificam a compatibilidade espacial entre utilizadores, usando para tal métricas propostas. Cada uma das métricas oferece um trade-off diferente entre a precisão para identificar um utilizador compatível e a complexidade necessária para a implementar. Foram usadas simulações numéricas para avaliar a performance das técnicas de seleção de utilizadores propostas (métricas e algoritmos), performance que foi comparada com as técnicas mais inovadoras.

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Joehanes, Roby. "Multiple-trait multiple-interval mapping of quantitative-trait loci." Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1605.

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Andersson, Emelie. "Multiple Platform First : Design Guidelines for Multiple Platform Games." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160991.

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This thesis investigates the two gaming platforms PC and Console and how the interfaces of games on these platforms could be designed more efficiently making it easier to release games on multiple platforms. In other words, how could the Multiple Platform First method look. Little previous work exist on this problem so this thesis work gathers information from other industries and also research on user interfaces in games in general. By looking at games running on both platforms different best practises and common solutions were discovered. A study was conducted testing different in-game components on users. The components were selected to test if the users would accept non-traditional components since users detect when playing on an interface not intended for the platform. This makes the study very complicated since the "best" solution might not work if the users does not accept it for the intended platform. Concepts were designed to combine the testing of solutions with the users opinion of the solutions. The chosen concepts were researched both in literature and by looking at present implementations in games. To be able to user test the solutions they were iterated from low fidelity prototypes on paper to high fidelity prototypes that were playable in Unity. The prototypes were tested on users and data gathered through Think Aloud comments and questionnaire answers. This study presents a first draft of how a multiple platform approach can be achieved.

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Di, Viesti Pasquale <1994&gt. "Colocated multiple-input multiple-output radars for smart mobility." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10113/1/Di_Viesti_Pasquale_Thesis.pdf.

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In recent years, radars have been used in many applications such as precision agriculture and advanced driver assistant systems. Optimal techniques for the estimation of the number of targets and of their coordinates require solving multidimensional optimization problems entailing huge computational efforts. This has motivated the development of sub-optimal estimation techniques able to achieve good accuracy at a manageable computational cost. Another technical issue in advanced driver assistant systems is the tracking of multiple targets. Even if various filtering techniques have been developed, new efficient and robust algorithms for target tracking can be devised exploiting a probabilistic approach, based on the use of the factor graph and the sum-product algorithm. The two contributions provided by this dissertation are the investigation of the filtering and smoothing problems from a factor graph perspective and the development of efficient algorithms for two and three-dimensional radar imaging. Concerning the first contribution, a new factor graph for filtering is derived and the sum-product rule is applied to this graphical model; this allows to interpret known algorithms and to develop new filtering techniques. Then, a general method, based on graphical modelling, is proposed to derive filtering algorithms that involve a network of interconnected Bayesian filters. Finally, the proposed graphical approach is exploited to devise a new smoothing algorithm. Numerical results for dynamic systems evidence that our algorithms can achieve a better complexity-accuracy tradeoff and tracking capability than other techniques in the literature. Regarding radar imaging, various algorithms are developed for frequency modulated continuous wave radars; these algorithms rely on novel and efficient methods for the detection and estimation of multiple superimposed tones in noise. The accuracy achieved in the presence of multiple closely spaced targets is assessed on the basis of both synthetically generated data and of the measurements acquired through two commercial multiple-input multiple-output radars.

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Walker, Emily N. "The Emotional Needs of Mothers of Multiple Birth Children." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149682/.

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The purpose of this study was to assess the emotional support needs of mothers of multiple birth children based on administration of a survey the researcher developed. The survey consisted of 25 demographic items, six 6-point Likert scale items, and three open-ended questions. Likert scale items were based on amount of perceived emotional support mothers received in their environments at the time of survey administration. Open-ended questions addressed negative and positive aspects of parenting multiples and emotional support needs. The sample consisted of 171 mothers of multiple birth children from 23 states in the United States. Participants ranged in age from 20-50 years old with 38% not reporting age. Participants were 95.3% Caucasian, 0% African-American, 1.8% Asian, 0% Native American and 1.2% other; of these, 5.8% were Hispanic. We used demographic statistics and constant comparison to determine basic demographic characteristics of this sample and to identify emotional support needs of mothers of multiple birth children. We used Pearson product moment correlation to determine potential relationships between variables. Results indicated a statistically significant positive correlation between overall life satisfaction and partner satisfaction (r = .420, n = 170, p < 0.01). Therefore, mothers of multiples experience increased satisfaction with their lives when they receive greater support from partners. Also, results indicated a statistically significant positive correlation between partner satisfaction and partner caretaking responsibilities (r = .305, n = 169, p < 0.01). As partners of mothers of multiples increase contribution to caretaking of children, mothers demonstrate greater relationship fulfillment. Implications for mental health professionals working with mothers of multiple birth children are discussed.

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Earp, Matthew N. "All Hexahedral Meshing of Multiple Source, Multiple Target, Multiple Axis Geometries Via Automatic Grafting and Sweeping." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd762.pdf.

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Holmberg, Johannes. "Analysis of a multiple dispatch algorithm." Thesis, Linköping University, Department of Computer and Information Science, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2218.

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The development of the new programming language Scream, within the project Software Renaissance, led to the need of a good multiple dispatch algorithm. A multiple dispatch algorithm, called Compressed n-dimensional table with row sharing; CNT-RS, was developed from the algorithm Compressed n-dimensional table, CNT. The purpose of CNT-RS was to create a more efficient algorithm. This report is the result of the work to analyse the CNT-RS algorithm.

In this report the domain of multiple dispatch, the multiple dispatch algorithm CNT and the new extended algorithm CNT-RS are presented. The correctness of CNT- RS algorithm is shown and it’s proven that the CNT-RS algorithm is at least as good as the CNT algorithm, in regards to space complexity of the dispatch structure.

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Oladeinde, Abiola Omobolaji. "Linear demultiple solution based on bottom-multiple generator (BMG) approximation: subsalt example." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4407.

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Significant quantities of hydrocarbons are found in complex salt environments. One of the modern challenges of exploration and production activities is to image below salt. This challenge arises from the complexities of salt structures, weak primaries from the subsalt, and the interference of free-surface multiples with the weak primaries of the subsalt. To effectively process subsalt data, we need to develop a method of attenuating free-surface multiples that preserves the amplitude and phase of primaries and does not introduce artifacts at either near and far offsets. In this thesis, we will demonstrate that the weak primaries of the subsalt can be preserved while attenuating free-surface multiples. The method used for the demonstration is the bottom-multiple generator (BMG) reflector approximation. This technique requires that a portion of the data containing only primaries be defined. A multidimensional convolution of the data containing only primaries with the actual data will predict free-surface multiples and hence is used to attenuate free-surface multiples from the actual data. This method is one of the most effective methods for attenuating free-surface multiples; however, the method requires muting data at the BMG location. One of the issues investigated in this thesis, is to establish the sensitivity of the BMG demultiple technique when the mute at the BMG location end up cutting some seismic reflections, which can be the case in complex environments such as the Gulf of Mexico and Gulf of Guinea, where freesurface multiples interfere with primaries. For this investigation, we generated synthetic data through the 2D elastic finite-difference modeling technique. The synthetic seismic data contain primaries; free-surface multiples, and internal multiples, and direct waves acquired over a 2D geological model that depicts a shallow-water geology. In this thesis, we also investigate if the first step of the BMG demultiple technique can sufficiently attenuate free-surface multiples. For this investigation, we designed a 2D geological model, which depicts the deep offshore environment, and we generated synthetic data through the 2D elastic finite-difference modeling technique. After performing the various investigations mentioned above, the following conclusions were made, that the demultiple result is not affected when the mute at the BMG location end up cutting some primaries, that the first step of the BMG demultiple technique is not sufficient for the demultiple, and that the weak subsalt primaries are preserved during demultiple processes. We compared shot gathers and zero offset data before and after the demultiple.

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Gunton, Richard Michael. "Density-dependence in plant populations : multiple processes and multiple scales." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485169.

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The abundance of conspecific neighbours is one detenninant of individual plants' fitness. Moreover, intraspecific interactions' are essential to the temporal and spatial dynamics of populations, which detennine a species' local pers'istence or extinction. In this thesis I explore how different measures of neighbourhood density (in particular, those obtained by varying the area over which density is measured) may explain the perfonnance ofindividuals, using white campion (Silene /atifolia) as a model species. During establishment of seedlings, a glasshouse experiment showed that the intensity of competition depends on the size and. species-frequency of neighbours, reducing growth rates and increasing mortality at higher densities. Growth rate over the '' first 11 days was best explained by the size of neighbours within 3.2-cm squares, but by 55 days the .frequency of grass neighbours within 16-cm squares had be~ome the most important factor. A 2-year field experiment showed negative effects of conspecific density on herbivory that were strongest among density treatments'in 4-m squares. There were also positive effects on survival; an improved analysis using neighbourhood circles showed . peak effects in neighbourhoods extending to 0.24 m (0.48 m diameter). Seed production was negatively related to densities of plants at much coarser scaies (around 15 m radius); here a better predictor was the density of female flowers, which had negative ... effects peaking in neighbourhoods between 13 and 67 m in extent. A specialist seed herbivore inflicted the most damage in 6-m neighbourhoods with more female or fewer male flowers, although a model combining male flowers at 20 m and female flowers at 0.5 m showed positive effects ofboth sexes in one ofthe two years. The generality of these conclusions was explored by analysing data from a seminatural population. This emphasises the variability ofdensity effects and the importance of dealing with spatial autocorrelation whet) analysing effects at multiple scales. I conclude that much remains to be done if population ecology is to explain the spatial patterns ofplant populations at multiple scales.

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Yu, Kai. "Multiple-Input Multiple-Output Radio Propagation Channels : Characteristics and Models." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-138.

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Song, Ran. "Inversion of Multiple-View and Multiple-Scale Images of Surfaces." Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503329.

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Bale, Viktor. "Computationally efficient equalisation of broadband multiple-input multiple-output systems." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437110.

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Pablo, Rodriguez Juan Manuel. "Multiple Target Detection and Tracking in a Multiple Camera Network." Thesis, KTH, Kommunikationsnät, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175884.

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Given synchronized video sequences from a number of cameras withoverlapping fields of view, the detection and tracking of a prioriunknownnumber of individuals entering a determined area is considered,showingthat a generative model can accurately follow the individuals and handleeffectively such problems as occlusions in each view independently. Theaim of this thesis is to implement the exchange of information betweenthe cameras where the detection and tracking processes take place. Theinputs are obtained from synchronized videos and the frames are takenindividually to treat them as independent images. The proposed algo-rithm was implemented in MATLAB and results obtained on a personalcomputer are presented. The results show that the algorithm achievesgood tracking accuracy, has relatively low computational complexity, andat the same time it allows to observe the communication requirementsbetween the cameras and the processing node.

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Zeileis, Achim, and Yves Croissant. "Extended Model Formulas in R. Multiple Parts and Multiple Responses." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2009. http://epub.wu.ac.at/1056/1/document.pdf.

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Model formulas are the standard approach for specifying the variables in statistical models in the S language. Although being eminently useful in an extremely wide class of applications, they have certain limitations including being confined to single responses and not providing convenient support for processing formulas with multiple parts. The latter is relevant for models with two or more sets of variable, e.g., regressors/instruments in instrumental variable regressions, two-part models such as hurdle models, or alternative-specific and individual-specific variables in choice models among many others. The R package Formula addresses these two problems by providing a new class "Formula" (inheriting from "formula") that accepts an additional formula operator | separating multiple parts and by allowing all formula operators (including the new |) on the left-hand side to support multiple responses.
Series: Research Report Series / Department of Statistics and Mathematics

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42

Sellami, Noura. "Récepteurs itératifs pour les systèmes MIMO (Multiple-Input Multiple-Input)." Cergy-Pontoise, 2002. http://www.theses.fr/2002CERG0159.

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Ce travail porte sur l'étude des systèmes MIMO (multiple-input multiple-output) codés et plus particulièrement les méthodes d'égalisation et de décodage adaptées à ces systèmes. Nous optons à l'émission pour un système utilisant le multiplexage spatial via la structure BICM (Bit Interleaved Coded Modulation). La présence des entrelaceurs rend la réception optimale (égalisation et décodage conjoints) trop complexe. Afin de réaliser un bon compromis complexité/performance, nous proposons d'utiliser une structure de réception itérative. Dans le cas où le canal est sélectif en fréquence, l'égaliseur doit effectuer une égalisation temporelle en plus de l'égalisation spatiale. L'égaliseur optimal est généralement trop complexe dans ce cas. Ainsi, nous proposons pour réaliser un bon compromis complexité/performance d'utiliser l'égaliseur Liste-MAP qui est une version sous-optimale de l'égaliseur MAP basée sur la réduction des états du treillis et le traitement par survivants (PSP : Per Survivor Processing). Afin de lutter contre la propagation d'erreur, nous proposons d'utiliser un filtre adapté blanchissant qui permet de concentrer l'énergie du canal sur ses premiers coefficients. Enfin, nous nous intéressons au problème de l'estimation du canal dans le cas du canal sélectif en fréquence. Nous montrons que les erreurs d'estimation du canal sont équivalentes à une perte en rapport signal à bruit et nous donnons une approximation de cette perte. Puis, nous proposons pour améliorer la première estimation du canal, effectuée en utilisant les séquences d'apprentissage, d'utiliser l'algorithme EM (Expectation Maximisation) en l'intégrant dans notre récepteur itératif. Cette étude est ensuite étendue au cas des systèmes CDMA
In this work, we studied coded MIMO (multiple-input multiple-output) systems, in particular equalization and decoding methods. We choose to use at the transmitter a system based on spatial multiplexing using BICM (Bit Interleaved Coded Modulation) structure. Because of the presence of interleavers, the optimal receiver, based on joint equalization and decoding, is too complex. In order to achieve a good complexity/performance trade-off, we propose to use an iterative receiver. When the channel is frequency selective, the equalizer has to perform time equalization in addition to spatial one. The optimal equalizer is too complex in this case. In order to achieve a good complexity/performance trade-off, we consider a List-type MAP equalizer which is a sub optimal version of the MAP equalizer based on state reduction and Per Survivor Processing (PSP). In order to fight against error propagation, we propose to use a Whitened Matched Filter which concentrates the channel energy on its first taps. In the last part, we study channel estimation when the MIMO channel is frequency selective. First, we show that channel estimation errors are equivalent to a loss in signal to noise ratio and we provide an approximation of this loss. Then, in order to improve the first channel estimation performed using training sequences, we propose to integrate the EM (Expectation Maximisation) algorithm in our iterative receiver. This study is then extended to CDMA systems

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Li, Ran. "Optical multiple input and multiple output (MIMO) in multimode fibre." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:1770da43-e93b-462b-866f-beb5f972ce06.

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Recently, there has been a dramatic increase in the amount of data transmission within short range local area networks (LAN). Multimode fibre (MMF) is widely used in local area networks because of its coupling and alignment along with the low cost of related components. Graded index MMF has become common due to the reduction in pulse spreading; however, as demands for high bandwidth increase towards a future gigabit rate network, the typical MMF using conventional transmission methods will not be suitable. Meanwhile, this increasing demand for high speed data transmission will soon reach the Shannon capacity limit of single mode fibres. After multiple input and multiple output (MIMO) technology was successfully used in wireless communication, the researcher realised that the same idea could also be applied to an optical fibre network. Optical MIMO techniques are gaining interest in order to create parallel channels over orthogonal modes in a MMF or a few mode fibre (FMF). This approach could lead to a significant increase in the bandwidth distance product and be employed in the next 40Gb/s or even 100Gb/s optical fibre transmission systems. Generally speaking, optical MIMO appears to be the best solution to the bandwidth limitation problem in either short distance MMF or long distance FMF systems. This thesis focuses on designing a simple, cost-effective, and energy efficient optical MIMO system based on MMFs. This proposed system can be realised by combining radial offset launching and annular multi-segment detectors. First, in the initial work, we performed a theoretical and numerical study of the key impairments of MMFs, and the mode propagation in an MMF was analysed mathematically. The variation in electrical field intensity for linearly polarised (LP) modes in the core region of an MMF and the analytical solutions for power coupling coefficients in either radial offset launching or centre launching were presented. In addition, the modal time delays, impulse response, and transfer function were all introduced. Subsequently, the near field intensity pattern (NFP) was simulated at the output facet of the MMF, which indicated that the overall NFP suffered from blurring when it contained mode mixing, and that the intensity pattern was particularly sensitive to the random phase. According to the spatial distribution of the NFP, the annular detector can be exploited more efficiently. All of the results were calculated and plotted using the MATLAB program. Secondly, the optical MIMO model in the multimode fibre was briefly summarised, including the MIMO channel matrix H expression, a mathematical expression of optical MIMO capacity, MIMO channel estimation and an equalization method. Two metrics can be used to characterise the MIMO channel performance: condition number and crosstalk at each receiver. The numerical results demonstrated that the new type of annular multi-segment detector exhibits superior performance compared to the conventional multiple single mode fibre (SMF) detectors, making them attractive for future optical MIMO systems. Finally, the core work of this thesis can be divided into two parts: the modelling of a 10Gb/s intensity modulation direct detection (IM-DD) optical MIMO MMF system; and the modelling of an advanced 10Gb/s coherent differential phase shift keying (DPSK) MIMO FMF system. In both simulation systems, the important transmission parameters of intra-group mode mixing, modal dispersion, chromatic dispersion, and mode attenuation were considered and discussed in detail. In the IM-DD optical MIMO system, the optimization of the transceiver can be based upon the laser spot size and the power flux distribution emitted by the transmitter. Results from the simulation showed that the intra-group mode mixing had a limited impact on system performance, and due to its inability to compensate for linear impairments, the IM-DD optical MIMO was not favourable for long distance transmission systems. Nevertheless, the new type of optical fibre FMF seems to be the most promising candidate for use in long haul transmission systems. Therefore, the well-known DPSK modulation format in conjugation with the coherent detection deployed in FMF was studied. Both heterodyne and intradyne detection schemes were analysed followed by mathematical derivation and numerical simulation; the results illustrated that similar system performances can be achieved in both schemes. Meanwhile, the coherent DPSK simulation results also demonstrated that the linear impairments were almost compensated by the frequency domain MIMO equalization process, which resulted in system performance being independent to transmission distance for up to 10km. This advantage proved that the coherent optical DPSK MIMO system can be employed in long haul networks. As with an IM-DD optical MIMO system, optimization of a coherent MIMO system was also possible. However, in contrast to the optimization of an IM-DD MIMO system, a trade-off had to be made between sufficient spatial diversity at the transceiver and differential modal delay caused by modal dispersion; consequently, the numerical results showed that the proposed coherent optical DPSK MIMO gained reasonable good results without using any active device, such as a spatial light modulator and a mode converter. In conclusion, this proposed optical MIMO system provided easy implementation and integration and is feasible for use in future optical communication systems.

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44

Cao, Pan. "Resource Allocation for Multiple-Input and Multiple-Output Interference Networks." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-161382.

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To meet the exponentially increasing traffic data driven by the rapidly growing mobile subscriptions, both industry and academia are exploring the potential of a new genera- tion (5G) of wireless technologies. An important 5G goal is to achieve high data rate. Small cells with spectrum sharing and multiple-input multiple-output (MIMO) techniques are one of the most promising 5G technologies, since it enables to increase the aggregate data rate by improving the spectral efficiency, nodes density and transmission bandwidth, respectively. However, the increased interference in the densified networks will in return limit the achievable rate performance if not properly managed. The considered setup can be modeled as MIMO interference networks, which can be classified into the K-user MIMO interference channel (IC) and the K-cell MIMO interfering broadcast channel/multiple access channel (MIMO-IBC/IMAC) according to the number of mobile stations (MSs) simultaneously served by each base station (BS). The thesis considers two physical layer (PHY) resource allocation problems that deal with the interference for both models: 1) Pareto boundary computation for the achiev- able rate region in a K-user single-stream MIMO IC and 2) grouping-based interference alignment (GIA) with optimized IA-Cell assignment in a MIMO-IMAC under limited feedback. In each problem, the thesis seeks to provide a deeper understanding of the system and novel mathematical results, along with supporting numerical examples. Some of the main contributions can be summarized as follows. It is an open problem to compute the Pareto boundary of the achievable rate region for a K-user single-stream MIMO IC. The K-user single-stream MIMO IC models multiple transmitter-receiver pairs which operate over the same spectrum simultaneously. Each transmitter and each receiver is equipped with multiple antennas, and a single desired data stream is communicated in each transmitter-receiver link. The individual achievable rates of the K users form a K-dimensional achievable rate region. To find efficient operating points in the achievable rate region, the Pareto boundary computation problem, which can be formulated as a multi-objective optimization problem, needs to be solved. The thesis transforms the multi-objective optimization problem to two single-objective optimization problems–single constraint rate maximization problem and alternating rate profile optimization problem, based on the formulations of the ε-constraint optimization and the weighted Chebyshev optimization, respectively. The thesis proposes two alternating optimization algorithms to solve both single-objective optimization problems. The convergence of both algorithms is guaranteed. Also, a heuristic initialization scheme is provided for each algorithm to achieve a high-quality solution. By varying the weights in each single-objective optimization problem, numerical results show that both algorithms provide an inner bound very close to the Pareto boundary. Furthermore, the thesis also computes some key points exactly on the Pareto boundary in closed-form. A framework for interference alignment (IA) under limited feedback is proposed for a MIMO-IMAC. The MIMO-IMAC well matches the uplink scenario in cellular system, where multiple cells share their spectrum and operate simultaneously. In each cell, a BS receives the desired signals from multiple MSs within its own cell and each BS and each MS is equipped with multi-antenna. By allowing the inter-cell coordination, the thesis develops a distributed IA framework under limited feedback from three aspects: the GIA, the IA-Cell assignment and dynamic feedback bit allocation (DBA), respec- tively. Firstly, the thesis provides a complete study along with some new improvements of the GIA, which enables to compute the exact IA precoders in closed-form, based on local channel state information at the receiver (CSIR). Secondly, the concept of IA-Cell assignment is introduced and its effect on the achievable rate and degrees of freedom (DoF) performance is analyzed. Two distributed matching approaches and one centralized assignment approach are proposed to find a good IA-Cell assignment in three scenrios with different backhaul overhead. Thirdly, under limited feedback, the thesis derives an upper bound of the residual interference to noise ratio (RINR), formulates and solves a corresponding DBA problem. Finally, numerical results show that the proposed GIA with optimized IA-Cell assignment and the DBA greatly outperforms the traditional GIA algorithm.

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45

Rozanski, Marta. "Bendamustin in Kombination mit Thalidomid und Prednisolon (BPT) bei Patienten mit rezidiviertem oder refraktärem Multiplem Myelom: Ergebnisse einer Phase-I-Studie." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-97058.

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Thalidomid ist eine in der Therapie des fortgeschrittenen refraktären oder rezidivierten multiplen Myeloms (MM) wirksame Substanz, obwohl dosislimitierende Toxizitäten (DLT) ihren Einsatz beschränken können. In der vorliegenden Phase-I-Studie mit 28 Patienten mit rezidiviertem oder refraktärem MM nach konventioneller Chemotherapie oder Hochdosis (HD)-Chemotherapie mit Stammzelltransplantation (SCT) konnte gezeigt werden, dass eine Kombination von niedrig dosiertem Thalidomid mit Bendamustin und Prednisolon (BPT) die Wirksamkeit beibehält oder erhöht und gleichzeitig keine DLT auftritt. Die BPT-Therapie umfasste eine Dosis von Bendamustin (60mg/m2) Tag 1, 8 und 15 und Prednisolon (100mg) Tag 1, 8, 15 und 22, und eine eskalierende tägliche Dosis Thalidomid (50, 100, 200mg). Die Behandlungszyklen wurden alle 28 Tage bis zum Auftreten des maximalen Ansprechens, DLT oder Fortschreiten der Erkrankung wiederholt. 24 Patienten sprachen nach mindestens zwei Zyklen auf die Therapie an (vier komplette, sechs sehr gute partielle und 14 partielle Remissionen). Das mediane progressionsfreie Überleben und Gesamtüberleben für alle Patienten betrug 11 und 19 Monate. Nur leichte oder mittelschwere nicht-hämatologische Nebenwirkungen wurden beobachtet und kein Patient entwickelte dosislimitierende Hämatotoxizitäten. Die BPT-Therapie weist bei Patienten mit rezidiviertem oder refraktärem MM eine gute Verträglichkeit mit einem Ansprechen von über 80% auf. Die maximal tolerierte Dosis von Thalidomid wurde in dieser Studie nicht erreicht.

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Lysfjord, Ivar Håkon. "Multiple Power Domains." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9720.

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When new transistor technology is used in a microcontroller design, the transistors become smaller. They cannot withstand the same voltages as older technology, because of their size. The automotive industry still uses 5V as a standard voltage, and the automotive industry is a major costumer for microcontroller companies. The microcontroller must therefore be able to use5V. This must be done without the need of external voltage regulator. To still be a supplier to the automotive industry, the AVR needs to be able to withstand voltages up to 5.5V. The main problem with the new transistor technology is the leakage currents. Traditionally, the CMOS devices have used power only when during switching of logical levels. This is no longer true, since the leakage currents have become so large. When using new transistor technology, the dynamic power usage will be reduced, but the total power usage will be increased, if nothing is done to prevent it. One solution to this is to make a multiple power domain microcontroller. The idea is that one power domain can withstand voltages up to 5.5V. The microcontroller then uses an internal voltage regulator to scale down the voltage to a suitable level. The low voltage area will then have a suitable voltage level, which reduces both the dynamic- and leakage power usage. The different voltage domains uses different clock sources, so communicating between them requires both level shifters to deal with the different voltage levels, and synchronization logic to prevent metastability. This assignment uses two voltage domains, VIO and VCORE. Since voltage regulators are quite inefficient, it is most efficient to use only two domains. The VCORE domain contains most of the digital logic of the microcontroller, such as the CPU, SRAM and timers. This domain uses a high-speed clock source, and a VCORE data bus to communicate between each other. To communicate with the VIO domain, the data bus is connected to the VIO data bus through an asynchronous communication scheme block. This is because the VIO domain uses a low speed clock source. The usage of individual clock sources prevents clock skew problems that may occur when passing level shifters, and there is power saving by using only a low speed clock source on the VIO domain. The VIO domain contains the Power Management Unit (PMU). The PMU shall control the power usage of the microcontroller. During active mode, the PMU can set unused modules in sleep mode, or shut them completely off. Most of the power savings are during sleep mode though. This is because a microcontroller such as the AVR spends most of the time in sleep mode. To reduce the power usage in sleep mode, the leakage currents needs to be reduced. The best way of doing so is to disconnect the power from the circuits. If the voltage regulator is disconnected, and all the inputs are set to high impedance, the VCORE domain is completely disconnected from the power, and uses absolutely no power. An asynchronous wake up circuit is designed to make it possible to wake up the microcontroller from a sleep mode without the usage of synchronized digital logic. Then the low frequency oscillator can be turned off, and even more power is saved. The major disadvantage of the multiple power domain solution is the start up time from a sleep mode. If the power to the low voltage area is disconnected, the start up requires that all the capacitors become charged before the chip can start running again. The oscillator is shut off, and it takes time to stabilize the oscillator. Especially since the oscillator requires some stability in the voltage, and the voltage may not stable until the capacitors are charged. Simulations shows that the multiple power domain solution has great potential of power saving. The proposed asynchronous wake up circuit uses only 1.2275nA. This is significantly smaller than the AVR uses in the deepest sleep mode today. To get a secure microcontroller, a reset circuit has to be on to be able to reset the AVR if necessary. The power usage of the reset circuit used today is confidential Atmel information, and cannot be published in this assignment. By looking at the data sheet of a pico power circuit of the AVR, the ATmega329p, one can see that in the deepest sleep mode, the microcontroller uses 40nA at 1.8V. By assuming that the reset circuit does not use more that half of this current, the total amount of power that saved during a sleep mode by using the multiple power domain solution is about 47%.

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47

Sipahigil, Oktay. "Multiple Window Detectors." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612600/index.pdf.

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Energy or DFT detector using a fixed window size is very efficient when signal start time and duration is matched with that of the window'
s. However, in the case of unknown signal duration, the performance of this detector decreases. For this scenario, a detector system composed of multiple windows may be preferred. Window sizes of such a system will also be fixed beforehand but they will be different from each other. Therefore, one of the windows will better match the signal duration, giving better detection results. In this study, multiple window detectors are analyzed. Their false alarm and detection probability relations are investigated. Some exact and approximate values are derived for these probabilities. A rule of thumb for the choice of window lengths is suggested for the case of fixed number of windows. Detectors with overlapping window structure are considered for the signals with unknown delay. Simulation results are added for these types of detectors.

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Samoila, Lavinia Andreea. "Multiple Entity Reconciliation." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187010.

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Living in the age of "Big Data" is both a blessing and a curse. On he one hand, the raw data can be analysed and then used for weather redictions, user recommendations, targeted advertising and more. On he other hand, when data is aggregated from multiple sources, there is no guarantee that each source has stored the data in a standardized or even compatible format to what is required by the application. So there is a need to parse the available data and convert it to the desired form. Here is where the problems start to arise: often the correspondences are not quite so straightforward between data instances that belong to the same domain, but come from different sources. For example, in the film industry, information about movies (cast, characters, ratings etc.) can be found on numerous websites such as IMDb or Rotten Tomatoes. Finding and matching all the data referring to the same movie is a challenge. The aim of this project is to select the most efficient algorithm to correlate movie related information gathered from various websites automatically. We have implemented a flexible application that allows us to make the performance comparison of multiple algorithms based on machine learning techniques. According to our experimental results, a well chosen set of rules is on par with the results from a neural network, these two proving to be the most effective classifiers for records with movie information as content.

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Dugas, Hugues. "Le tableau multiple." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq25301.pdf.

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50

Suderman, Matthew. "Multiple message broadcasting." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0024/MQ51480.pdf.

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