Tesis: "Coding gain"

1

Forman, Michael A., Ken Condreva, Gary Kirchner y Kevin Lam. "Quantifying Coding Gain from Telemetry Data Combining". International Foundation for Telemetering, 2008. http://hdl.handle.net/10150/606214.

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ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California
A method for combining telemetry data and quantifying the resulting coding gain for a ballistic missile test flight is presented. Data received from five ground stations in 54 data files with 18 million intermittent frames is combined, to create a single file with 1.5 million continuous frames. Coding gain provided by data combining is as high as 30 dB, with a useful improvement of 5 dB at boost and terminal stages. With frame reconstruction techniques, erroneous words in a frame are reduced from 2.1% to 0.12 %.

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2

Hussin, Mohamed Nuri Ahmed. "Diversity gain enhancement for extended orthogonal space-time block coding in wireless communications". Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22706.

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Transmit diversity is a powerful technique for enhancing the channel capacity and reliability of multiple-input and multiple-output (MIMO) wireless systems. This thesis considers extended orthogonal space-time block coding (EO-STBC) with beamsteering angles, which have previously been shown to potentially achieve full diversity and array gain with four transmit and one receive antenna. The optimum setting of beamsteering angles applied in the transmitter, which has to be calculated based on channel state information (CSI) at the receiver side, must be quantised and feed back to the transmitter via a reverse feedback link. When operating in a fading scenario, channel coefficients vary smoothly with time. This smooth evolution of channel coefficients motivates the investigation of differential feedback, which can reduce the number of feedback bits, while potentially maintaining near optimum performance. The hypothesis that the smooth evolution of channel coefficients translates into smooth evolution of feedback angles is justified by simulations. The maximum attainable gain under optimum unquantised beamsteering angles is derived, which allows to experimentally assess the effect that quantisation in the feedback channel has on the system performance. In characterising the degradation experienced through time-variation and limited quantised feedback, we demonstrate that the new differential feedback approach offers a practical bandwidth-efficient scheme. Simulation results with Doppler spread conditions confirm that the proposed scheme achieves significant bandwidth savings over previously proposed systems. With a single feedback bit per beamsteering angle the proposed differentially encoded EO-STBC approach can achieve near optimum performance and exceed the performance of non-differential feedback schemes that employ a higher word length. We further propose combining differential encoding with channel estimation that is practically useful because the EO-S. We further propose combining differential encoding with channel estimation that is practically useful because the EO-STBC receiver requires knowledge of the channel coefficients for both detecting the transmitted symbols as well as for computing the optimum angles to be fed back to the transmitter. Channel estimation accompanied by a decision-directed (DD) tracking scheme by means of a Kalman filter has been adopted. The Kalman filter exploits the smooth evolution of the channel coefficients as a motivation for tracking as well as for differential feedback. Further we propose applying an auto-regressive (AR) predictor with order greater than one in the Kalman model. This can be shown to offer advantages in terms of temporal smoothness when addressing channels whose coefficient trajectories evolve smoothly. Simulation results show that the overall EO-STBC system achieves longer tracking periods with suitable bit error (BER) values, and that the performance of the proposed system offers a distinct advantage for lower Doppler spreads with the inclusion of second order AR model instead of the standard first order AR model. The earlier work on EO-STBC systems is for frequency-flat channels. However, in frequency-selective channel a multi-carrier approach can help to split into independent subcarriers. Therefore, the EO-STBC scheme is then applied for a dedicated chirp-based multicarrier based on a fractional Fourier transformer (FrFT) system over doubly dispersive channels, where FrFT-domain is developed to further increase robustness against channel time-variations. Applied in nearstationary channel conditions, the performance of orthogonal frequency division multiplexing (OFDM) receivers that mitigate crosstalk between individual subcarriers are evaluated for open and closed loop schemes. A higher degree of non-stationarity in mobile scenarios will destroy the orthogonality of subcarriers and result in intercarrier interference (ICI) and intersymbol interference (ISI). In this case, minimum mean square error (MMSE) of a reduced system matrix is considered for open loop EO-STBC. The equaliser complexity can be decreased even furtherby using least squares minimum residual (LSMR) iterative algorithm, equalisation are underlined by simulations, demonstrating the overall practical use if the contributions wihtin this thesis towards EO-STBC diversity schemes over both time- and frequency-dispersive channels.

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3

Bampasakis, Dimitris. "Inhibitory synaptic plasticity and gain modulation in cerebellar nucleus neurons". Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17179.

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Neurons can encode information using the rate of their action potentials, making the relation between input rate and output rate a prominent feature of neuronal information processing. This relation, known as I{O function, can rapidly change in response to various factors or neuronal processes. Most noticeably, a neuron can undergo a multiplicative operation, resulting in a change of the slope of its I{O curve, also know as gain change. Gain changes represent multiplicative operations, and they are wide- spread. They have been found to play an important role in the encoding of spatial location and coordinate transformation, to signal amplification, and other neuronal functions. One of the factors found to introduce and control neuronal gain is synaptic Short Term Depression (STD). We use both integrate-and- re and conductance based neuron models to identify the effect of STD in excitatory and inhibitory modulatory input. More specifically, we are interested in the effect of STD at the inhibitory synapse from Purkinje cells to cerebellar nucleus neurons. Using a previously published, biologically realistic model, we find that the presence of STD results in a gain change. Most importantly we identify STD at the inhibitory synapse to enable excitation-mediated gain control. To isolate the mechanism that allows excitation to control gain, even though STD is applied at a different synapse, we first show that the overall effect is mediated by average conductance. Having done this, we find that the effect of STD is based on the non-linearity introduced in the relation between input rate and average conductance. We find this effect to vary, depending on the position of the I{O function on the input rate axis. Modulatory input shifts the I{O curve along the input rate axis, consequently shifting it to a position where STD has a different effect. The gain differences in the STD effects between the two positions enable excitation to perform gain control.

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4

Heshmati, Saeideh. "Actions Speak Louder Than Words: How Should Attributional Feedback be Communicated to Students in Classrooms for the Most Achievement Gain in Mathematics?" Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/581324.

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While the role of attributional feedback on student learning and achievement has been previously studied in laboratory settings, the importance of these types of feedback in real-time classroom settings is yet to be examined. This study attempted at exploring whether attributional feedback is present in interactions between teachers and students in natural classroom settings and how much they contribute to students' achievement in mathematics. Using an observational coding system, 55 one hour mathematics classrooms were coded for three different types of attributional feedback: direct attributional feedback, indirect attributional feedback, and strategy feedback. Direct attributional feedback consisted of explicit statements that were effort-oriented, ability- oriented, or knowing-oriented. Indirect attributional feedback consisted of teacher behavior that implicitly conveyed attributional messages to students. Behaviors such as unsolicited offers of help, giving credit to students, abandoning students, and calling out student name publicly were coded as indirect attributional behavior in this study. In addition, "why", "how", "what" strategy questions and strategy statements were coded as strategy feedback in this study. The results of this study indicated that while both direct and indirect attributional feedback are present in natural classroom settings, there is a significant difference between the number of times each type occurs. Teachers are more likely to convey attributional messages to students through indirect behavior compared to explicit attributional statements. When these types of feedback were examined in a model predicting students' mathematics achievement scores, the results showed that attributional feedback on their own significantly predicted student achievement but when it was combined with strategy feedback a stronger association with achievement scores occurred. Amazingly, it should be noted that in this model, direct attributional feedback indicated a negative association with mathematics achievement whereas indirect attributional feedback and strategy feedback indicated a positive association. These findings reveal that attributional feedback play an important role in student achievement in mathematics and the most effective way to present students with these types of feedback is to convey them indirectly and in combination with strategy feedback.

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5

Bhuiya, Iftekharul Karim. "Design of a High Speed AGC Amplifier for Multi-level Coding". Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6509.

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This thesis presents the design of a broadband and high speed dc-coupled AGC amplifier for multi-level (4-PAM) signaling with a symbol rate of 1-GS/s ( 2-Gb/s ) . It is a high frequency analog design with several design challenges such as high -3 dB bandwidth ( greater than 500 MHz ) and highly linear gain while accommodating a large input swing range ( 120 mVp-p to 1800 mVp-p diff.) and delivering constant

differential output swing of 1700 mVp-p to 50-ohm off-chip loads at high speed. Moreover, the gain control circuit has been designed in analog domain. The amplifier incorporates both active and passive feedback in shunt-shunt topology in order to achieve wide bandwidth. This standalone chip has been implemented in AMS 0.35 micron CMOS process. The post layout eye-diagrams seem to be quite satisfactory.

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6

Ben, Chikha Haithem. "Etude et Amélioration de Turbo-Codage Distribué pour les Réseaux Coopératifs". Thesis, Valenciennes, 2012. http://www.theses.fr/2012VALE0011/document.

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Dans les systèmes radio mobiles, la diversité représente une technique efficace pour lutter contre l’évanouissement dû aux multi-trajets. La pleine diversité spatiale est atteinte dans les systèmes multiple-input multiple-output (MIMO). Mais, souvent l’intégration d’antennes multiples au niveau de l’émetteur ou du récepteur est coûteuse. Comme alternative, dans les réseaux sans fil multi-hop, la diversité coopérative garantit des gains de diversité spatiale en exploitant les techniques MIMO traditionnelles sans avoir besoin d’antennes multiples. En outre, la diversité coopérative fournit au réseau : un débit important, une énergie réduite et une couverture d’accès améliorée.Dans ce contexte, l’objectif de cette thèse est de concevoir des schémas de codage pour le canal à relais afin de réaliser une meilleure performance en termes de gain de diversité et de gain de codage. D’abord, nous étudions un système de turbo-codage distribué à L-relais en mode soft-decode-and-forward. Ensuite, nous proposons un système de turbocodage coopératif distribué à L-relais en utilisant la concaténation en parallèle des codes convolutifs. Enfin, afin d’améliorer la fiabilité de détection au niveau du noeud relais, nous proposons la technique de sélection d’antenne/relayage-soft. Pour une modulation BPSK, nous dérivons des expressions de la borne supérieure de la probabilité d’erreurbinaire où les différents sous-canaux sont supposés à évanouissement de Rayleigh, indépendants et pleinement entrelacés avec une information instantanée d’état de canal idéal. Une validation des résultats théoriques est également menée par la simulation
Diversity provides an efficient method for combating multipath fading in mobile radio systems. One of the most common forms of spatial diversity is multiple-input multipleoutput (MIMO), where full diversity is obtained. However, embedding multiple antennas at the transmitter or the receiver can sometimes be expensive. As an alternative to collocated antennas, cooperative diversity in wireless multi-hop networks confirms their ability to achieve spatial diversity gains by exploiting the spatial diversity of the traditional MIMO techniques, without each node necessarily having multiple antennas. In addition, cooperative diversity has been shown to provide the network with importantthroughput, reduced energy requirements and improved access coverage.In light of this, the objective of this thesis is to devise coding schemes suitable for relay channels that aim at showing the best compromise between performance of diversity and coding gains. Firstly, we investigate a distributed turbo coding scheme dedicated to L-relay channels operating in the soft-decode-and-forward mode. Then, we present a proposed distributed turbo coded cooperative (DTCC) scheme, called parallel concatenated convolutional-based distributed coded cooperation. Finally, we investigate antenna/soft-relaying selection for DTCC networks in order to improve their end-to-end performance. Assuming BPSK transmission for fully interleaved channels with ideal channel state information, we define the explicit upper bounds for error probability inRayleigh fading channels with independent fading. Both theoretical limits and simulation results are presented to demonstrate the performances

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7

Ganji, Saichand. "Space-Time Block Coding to Achieve Spatial Diversity in a Multiple Input Multiple Output System". Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1534432423784957.

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8

Leung, Raymond Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Scalable video compression with optimized visual performance and random accessibility". Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/24192.

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This thesis is concerned with maximizing the coding efficiency, random accessibility and visual performance of scalable compressed video. The unifying theme behind this work is the use of finely embedded localized coding structures, which govern the extent to which these goals may be jointly achieved. The first part focuses on scalable volumetric image compression. We investigate 3D transform and coding techniques which exploit inter-slice statistical redundancies without compromising slice accessibility. Our study shows that the motion-compensated temporal discrete wavelet transform (MC-TDWT) practically achieves an upper bound to the compression efficiency of slice transforms. From a video coding perspective, we find that most of the coding gain is attributed to offsetting the learning penalty in adaptive arithmetic coding through 3D code-block extension, rather than inter-frame context modelling. The second aspect of this thesis examines random accessibility. Accessibility refers to the ease with which a region of interest is accessed (subband samples needed for reconstruction are retrieved) from a compressed video bitstream, subject to spatiotemporal code-block constraints. We investigate the fundamental implications of motion compensation for random access efficiency and the compression performance of scalable interactive video. We demonstrate that inclusion of motion compensation operators within the lifting steps of a temporal subband transform incurs a random access penalty which depends on the characteristics of the motion field. The final aspect of this thesis aims to minimize the perceptual impact of visible distortion in scalable reconstructed video. We present a visual optimization strategy based on distortion scaling which raises the distortion-length slope of perceptually significant samples. This alters the codestream embedding order during post-compression rate-distortion optimization, thus allowing visually sensitive sites to be encoded with higher fidelity at a given bit-rate. For visual sensitivity analysis, we propose a contrast perception model that incorporates an adaptive masking slope. This versatile feature provides a context which models perceptual significance. It enables scene structures that otherwise suffer significant degradation to be preserved at lower bit-rates. The novelty in our approach derives from a set of "perceptual mappings" which account for quantization noise shaping effects induced by motion-compensated temporal synthesis. The proposed technique reduces wavelet compression artefacts and improves the perceptual quality of video.

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9

Ahmed, Ebad. "Delay gains from network coding in wireless networks". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41253.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
Includes bibliographical references (p. 73-77).
We consider a single-hop cellular wireless system with a single source (base station) broadcasting a stream of incoming files to multiple receivers over stochastic time-varying channels with non-zero erasure probabilities. The base station charges a price per receiver per file with the aim of maximizing its profit. Customers who wish to transmit files to the receivers decide to enter the system based on the price, the queuing delay, and the utility derived from the transaction. We look at network coding and scheduling as possible strategies for file transmission, and obtain approximate characterizations of the optimal customer admission rate, optimal price and the optimal base-station profit as functions of the first and second moments of the service time processes under mild assumptions. We show that network coding leads to significant gains in the base station profits as compared to scheduling, and also demonstrate that the optimal network coding window size is highly insensitive to the number of receivers, which suggests that pricing and coding decisions can be decoupled. We also investigate the behavior of network coding in the case where the number of receivers is sufficiently large, and derive scaling laws for the asymptotic gains from network coding. We subsequently propose a way to extend our analysis of single-source, multiple-receiver systems to multiple-source, multiple-receiver systems in general network topologies and obtain explicit characterizations of the file download completion time under network coding and scheduling, also taking into account the effects of collisions and interference among concurrent packet transmissions by two or more sources.
(cont.) Our formulation allows us to model multi-hop networks as a series of single-hop multiple-source, multiple-receiver systems, which provides a great deal of insight into the workings of larger and denser multi-hop networks such as overlay networks and peer-to-peer systems, and appears to be a promising application of network coding in such networks in the future.
by Ebad Ahmed.
M.Eng.

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10

Cunningham, Tommy Joseph. "THE CLINICAL USEFULNESS OF VECTOR CODING VARIABILITY IN FEMALE RUNNERS WITH AND WITHOUT PATELLOFEMORAL PAIN". UKnowledge, 2012. http://uknowledge.uky.edu/khp_etds/7.

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It has been suggested that Patellofemoral Pain (PFP) may be the result of a coordinate state which exhibits less joint coordination variability. The ability to relate joint coordination variability to PFP pathology could have many clinical uses; however, evidence to support clinical application is lacking. Vector coding’s coupling angle variability (CAV) has been introduced as a possible analysis method to quantify joint coordination variability. The purpose of this study was to assess the clinical usefulness of CAV measures from a dynamical systems perspective. This involved establishing the precision limits of CAV measures when physiological conditions are held constant, altering control parameters of knee pain and population then determining if the observed changes in CAV were clinically meaningful. 20 female recreational runners with PFP and 21 healthy controls performed a treadmill acclimation protocol then ran at a self-selected pace for 15 minutes. 3-D kinematics, force plate kinetics, knee pain and perceived exertion were recorded each minute. CAV were calculated for six knee-ankle combinations for 2 sets of 5 non-consecutive stride cycles at each capture period. Data were selected for the PFP group at a high (=>3) and low (<=high-2) pain level in a non-exhausted state (<14). Healthy data were used from the 11th minute of the running. Levels of agreement were performed between the 2 sets of CAV measures for both populations, a paired t-test compared low to high pain CAV measures and independent t-tests compared populations at the high pain state. Several CAV measures showed a significant increase in value with an increase in pain and were significantly greater for the PFP group. None of the observed changes exceeded the precision limits of all CAV measures investigated. These results do not agree with previous claims that less variability is indicative of pathology but rather the opposite. This suggests that there might be an optimal amount of variability to maintain a healthy coordinate state with deviations in any direction being detrimental. However; due to the volatile nature of CAV measures, the clinical use of CAV is not recommended using current analysis methods since changes observed weren’t considered clinically meaningful.

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11

Hucher, Charlotte. "Définition et analyse des performances de protocoles coopératifs". Paris, Télécom ParisTech, 2009. https://pastel.hal.science/pastel-00683338.

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Dans un réseau coopératif, différents noeuds coopèrent afin de créer un réseau d’antennes virtuel et exploiter la diversité spatio-temporelle. On s’intéresse d'abord au canal à relai. Afin d'améliorer les performances à bas SNR, on propose une stratégie adaptative pour les protocoles ”amplify-and-forward” (AF) et ”decode-and-forward (DF) qui détermine la meilleure technique de transmission en fonction du canal. Afin de définir un protocole DF à la fois performant et facile à implémenter, on propose ensuite d'utiliser un décodage incomplet aux relais. Cette technique permet d’atteindre les gains de multiplexage et de diversité maximaux, son DMT est le même que celui du protocol AF non-orthogonal (NAF). Pour réduire la complexité aux relais, deux nouvelles méthodes de décodage sont proposées, basées pour l’une sur la structure des codes TAST, et pour l’autre sur une approximation diophantienne. Dans le cas où plusieurs sources transmettent simultanément, on parle de canal coopératif à accès multiple (CMA). Une implémentation pratique et deux améliorations du protocole CMA-NAF sont proposées, ainsi qu’une variante utilisant une stratégie DF. Ces protocoles permettent d’atteindre de meilleures performances asymptotiques et leur DMT est plus proche de la borne MISO. Enfin, si le lien direct entre source et destination est inutilisable, on utilise une stratégie multi-saut. Dans cette thèse, on propose un protocole pour le canal ”K-parallel-path” (KPP), basé sur la sélection de chemin combinée avec un code spatio-temporel de faible dimension. Ce protocole permet d’atteindre les limites théoriques du canal tout en ayant une complexité limitée
In cooperative networks, multiple nodes cooperate to form a virtual antenna array and exploit space-time diversity. The relay channel is first investigated. In order to improve performance at low SNRs, an adaptive strategy is proposed for both amplify-and-forward (AF) and decode-and-forward (DF) protocols. This strategy chooses the best transmission scheme in term of mutual information for each channel realization. To define an easily implementable and efficient DF protocol, we propose to use an incomplete decoding at relays. This technique provides both full rate and full diversity. Its DMT is similar to the one of the well-known non-orthogonal AF (NAF). In order to reduce the decoding complexity at relays, we also propose two decoding methods based on the space-time block code (STBC) structure and diophantine approximation, respectively. When several sources need to transmit simultaneously, a cooperative multiple access (CMA) channel has to be considered. A practical implementation and two modifications of the CMA-NAF protocol defined by Azarian et al. Are proposed, as well as a DF variant, the CMA-IDF. These protocols provide better asymptotic performance and their DMT is closer to the MISO bound. Finally, if the direct link between source and destination is nonexistent or experiences too much fading, a multihop strategy has to be used. In this thesis, a protocol is proposed for the K-parallel-path (KPP) network, based on path selection combined with a small STBC. This protocol achieves the optimal DMT of the KPP channel with a limited complexity

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12

Remor, Federica. "Analisi e implementazione del catalogo stellare della missione Gaia". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18109/.

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La missione spaziale Gaia è una missione voluta dall’ESA (European Space Agency) per studiare ed analizzare i corpi presenti nella nostra galassia, la Via Lattea e non solo. Segue le orme della precedente missione Hipparcos, analizzando diversi parametri fondamentali per lo studio dei corpi celesti e ponendosi come obiettivo di realizzare un catalogo formato da più di un miliardo di stelle. Lo studio della missione, delle release pubblicate e, più in particolare, dei corpi catalogati in Gaia sono un ottimo punto di partenza per procedere con una ricerca più approfondita all’interno del catalogo stesso; inoltre, si rivolge particolare attenzione ai parametri fondamentali che caratterizzano un corpo celeste. La ricerca viene effettuata tramite l’implementazione di un codice all’interno di un dato linguaggio di programmazione. Questo risulta molto utile poiché permette di addentrarsi in modo diretto nei dati e nei risultati ottenuti da Gaia in questi anni di esplorazione. Il codice implementato, inoltre, consente la realizzazione di una serie di grafici volti allo studio e all’analisi più approfondita dei dati catalogati in Gaia e permette il confronto tra diversi sottoinsiemi di corpi celesti.

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13

Michaels, Jonathan A. [Verfasser], Hansjörg [Akademischer Betreuer] [Gutachter] Scherberger, Alexander [Gutachter] Gail y Krishna V. [Gutachter] Shenoy. "Towards population coding principles in the primate premotor and parietal grasping network / Jonathan A. Michaels ; Gutachter: Hansjörg Scherberger, Alexander Gail, Krishna V. Shenoy ; Betreuer: Hansjörg Scherberger". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1122825307/34.

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Veld, Rijk in 't [Verfasser], Hansjörg [Akademischer Betreuer] [Gutachter] Scherberger y Alexander [Gutachter] Gail. "Neural coding of grasp force planning and control in macaque areas AIP, F5, and M1 / Rijk in 't Veld ; Gutachter: Hansjörg Scherberger, Alexander Gail ; Betreuer: Hansjörg Scherberger". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1117219453/34.

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Zuo, Shih-pei y 左仕沛. "Coding-Gain-Based Complexity Control for Motion Compensation in H.264 Video Decoding". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/64301746231008262928.

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碩士
國立中央大學
通訊工程研究所
99
Video Applications in mobile devices become more and more popular. The latest video compression standard H.264/AVC provides various coding tools to achieve high coding efficiency at the expense of high computational complexity. Because the computation capability of a mobile device is generally constrained, the full-scale H.264 video decoding may be not allowed for a mobile device. Therefore, a complexity control mechanism which adjusts the complexity of video coding computational complexity and maintains the Rate-Distortion (RD) performance is important. Most studies on complexity control focus on the encoding side. However, we propose a complexity control mechanism for video decoders because decoders are more popularly used. Motion compensation (MC) is the most complexity-consuming operation in H.264 video decoding, the complexity control of MC is critical and the first one to be considered in our work. This research proposes a Coding-Gain-Based layer (CGL) mechanism which controls MC complexity of the decoder by controlling allowable search point locations and partition modes in the encoder. The computational overhead of the proposed mechanism is totally just in the encoder. The simulation results show that the proposed mechanism can reduce decoding time up to 37% with less than 0.44 dB video quality degradation compared with no complexity constrained case. It can efficiently control the decoding complexity with only 2.43% error rate on average.

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16

Mare, Karel Petrus. "On the performance gain of STFC-LDPC concatenated coding scheme for MIMO-WiMAX". Diss., 2009. http://hdl.handle.net/2263/29915.

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In mobile communications, using multiple transmit and receive antennas has shown considerable improvement over single antenna systems. The performance increase can be characterized by more reliable throughput obtained through diversity and the higher achievable data rate through spatial multiplexing. The combination of multiple-input multiple-output (MIMO) wireless technology with the IEEE 802.16e-2005 (WiMAX) standard has been recognized as one of the most promising technologies with the advent of next generation broadband wireless communications. The dissertation introduces a performance evaluation of modern multi-antenna coding techniques on a MIMO-WiMAX platform developed to be capable of simulating space-selective, time-selective and frequency-selective fading conditions, which are known as triply-selective fading conditions. A new concatenated space-time-frequency low-density parity check (LDPC) code is proposed for high performance MIMO systems, where it is shown that the newly defined coding technique outperforms a more conventional approach by concatenating space-time blocks with LDPC codes. The analysis of the coding techniques in realistic mobile environments, as well as the proposed STFC-LDPC code, can form a set of newly defined codes, complementing the current coding schemes defined in the WiMAX standard.
Dissertation (MEng)--University of Pretoria, 2009.
Electrical, Electronic and Computer Engineering
unrestricted

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17

Backer, Alejandro (Alex). "Pattern Recognition in the Olfactory System of the Locust: Priming, Gain Control and Coding Issues". Thesis, 2002. https://thesis.library.caltech.edu/4610/2/Thesis.pdf.

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Object recognition requires both specificity, to ensure that stimuli with distinct behavioral relevance are distinguished, and invariance, to ensure that different instances of the same stimulus are recognized as the same under varied conditions (intensity, pitch, position,...). Psychophysical studies show that an odor can be perceived as identical over significant ranges of concentrations. Whether concentration invariance results, at least in part, from low-level neural phenomena rather than cognitive grouping is so far unknown.

I explore, firstly, the contribution of projection neurons (PNs) in the antennal lobe of the locust, the analog of the vertebrate olfactory bulb, to the recognition of odor identity across concentrations; and secondly, what role spike timing, neuronal identity, and synchronization among neuronal assemblies play in the encoding and decoding of odor information by downstream neurons.

I show the following:
A novel computerized odor delivery system capable of delivering binary mixtures in arbitrary ratios and with arbitrary timecourses selected in real-time.
The locust can recognize odors, and shows innate olfactory preferences.

PNs solve the task of encoding both odorant concentration and odorant identity, independently of concentration, in three ways. First, by multiplexing information in different response dimensions using a code that involves neuronal identity, spike timing (on a timescale slower than previously believed) and synchronization across a neuronal assembly. Second, via a novel phenomenon of experience-dependent plasticity that contributes to PNs’ invariance to concentration and sensitizes PNs after exposure to an odor at high concentration, contrary to the adaptation exhibited by receptors. Third, a phenomenon of gain control, whereby excitatory and inhibitory responses balance out massive changes in receptor activity as a function of odorant concentration, maintains the output of PNs within a small dynamic range.

A further mechanism of gain control contributing to keep the activity of early olfactory circuits relatively constant across the wide dynamic range of odorant concentrations in the air is the physical chemistry of odorant reception confers the olfactory system invariance to odorant volatility, a physical property that has hitherto been believed to play a fundamental role in an odorant’s effectiveness.

Response patterns sometimes exhibit stable representations over large composition ranges and then abrupt transitions as a function of concentration and mixture composition, suggesting the difference between “same” and “different” odors may be delineated by sharp boundaries in odor space.

Finally, how is the distributed code for odors in PN assemblies decoded? I show that although synchronization among PN assemblies does not augment stimulus information in PN temporal responses, it is necessary for the read-out of odor information by downstream neurons. In sum, early olfactory circuits appear to employ plasticity, gain control and temporal coding across synchronizing neuronal assemblies to solve the odor recognition problem across multiple concentrations.

Appendices show that the variability of PN responses is correlated across neurons, show how to produce non-cyclic Winnerless Competition (WLC) and a learning rule that causes random networks to self-organize into WLC, present an exact hypothesis test for binomial distributions, improvements to sliding-window cross-correlation and to the K-nearest neighbor classification algorithm, a combinatorial analysis of the connectivity between the locust antennal lobes and mushroom bodies, a didactic exposition of Victor and Purpura’s spike cost-based metric and an experiment showing heterogeneity along the length of the locust antenna.

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18

Liu, Ji-Hui y 劉濟輝. "Comparative analysis chicken genome to identify the gain & loss of protein-coding genes in evolution". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/89467195136001471667.

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碩士
國立中興大學
基因體暨生物資訊學研究所
100
According to the concept of evolution, the diversity of animals originated from a common ancestry, and the more closely related species have more similarities among their genome sequences. Chicken ancestor had diverged from mammals about 310 million years ago. To study phylogenetic evolution and genetic diversity of the chicken, we used human, zebrafish and chicken as representatives to build a comparative genomics analysis. Since chicken gene annotation (~17000) is lower than zebrafish in Ensembl database (over 30000), we think there are more genes that haven’t been annotated, though with 5% chicken genome not been sequenced. Therefore we verified gene annotation of chicken through the nr and EST databases of NCBI (National Center for Biotechnology Information) to avoid excessive gene-loss analysis. We found that there are 2131 genes lost, 70 newly annotated genes and 2693 unique genes gained in evolution. We expect these results can narrow the gap between our understanding of evolution biology and molecular genomics.

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19

Xu, Di. "Improved subband-based and normal-mesh-based image coding". Thesis, 2007. http://hdl.handle.net/1828/284.

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Image coding is studied, with the work consisting of two distinct parts. Each part focuses on different coding paradigm. The first part of the research examines subband coding of images. An optimization-based method for the design of high-performance separable filter banks for image coding is proposed. This method yields linear-phase perfect-reconstruction systems with high coding gain, good frequency selectivity, and certain prescribed vanishing-moment properties. Several filter banks designed with the proposed method are presented and shown to work extremely well for image coding, outperforming the well-known 9/7 filter bank (from the JPEG-2000 standard) in most cases. Several families of perfect reconstruction filter banks exist, where the filter banks in each family have some common structural properties. New filter banks in each family are designed with the proposed method. Experimental results show that these new filter banks outperform previously known filter banks from the same family. The second part of the research explores normal meshes as a tool for image coding, with a particular interest in the normal-mesh-based image coder of Jansen, Baraniuk, and Lavu. Three modifications to this coder are proposed, namely, the use of a data-dependent base mesh, an alternative representation for normal/vertical offsets, and a different scan-conversion scheme based on bicubic interpolation. Experimental results show that our proposed changes lead to improved coding performance in terms of both objective and subjective image quality measures.

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20

Vinodh, K. "Cooperative Communication Protocols : Diversity-Multiplexing Gain Tradeoff And Code Constructions". Thesis, 2007. http://hdl.handle.net/2005/505.

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Cooperative relay communication is a promising means of wireless communication in which cooperation is used to create a virtual transmit array between the source and the destination, thereby providing spatial diversity for combating the fading channel. In this thesis we develop cooperative communication protocols namely the orthogonal amplify-and-forward (OAF), non-orthogonal and orthogonal selection decode-and-forward (NSDF and OSDF) protocols. The diversity-multiplexing gain tradeoff (DMT) of the three protocols is determined and DMT-optimal distributed space-time code constructions are provided. The code construction is based on Cyclic Division Algebras. The codes constructed are sphere decodable and in some instances incur minimum possible delay. Included in our results is the perhaps surprising finding that the OAF and NAF protocols have identical DMT when the time durations of the broadcast and cooperative phases are optimally chosen to suit the respective protocol. Two variants of the NSDF protocol are considered: fixed-NSDF and variable-NSDF protocol. In the variable-NSDF protocol, the fraction of time occupied by the broadcast phase is allowed to vary with multiplexing gain. In the two-relay case, the variable-NSDF protocol is shown to improve on the DMT of the best previously-known static protocol for higher values of multiplexing gain. Our results also establish that the fixed-NSDF protocol has a better DMT than the NAF protocol for any number of relays.

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21

Naveen, N. "Diversity-Mutiplexing Tradeoff Of Asynchronous Cooperative Relay Networks And Diversity Embedded Coding Schemes". Thesis, 2008. http://hdl.handle.net/2005/828.

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This thesis consists of two parts addressing two different problems in fading channels. The first part deals with asynchronous cooperative relay communication. The assumption of nodes in a cooperative communication relay network operating in synchronous fashion is often unrealistic. In this work we consider two different models of asynchronous operation in cooperative-diversity networks experiencing slow fading and examine the corresponding Diversity-Multiplexing Tradeoffs (DMT). For both models, we propose protocols and distributed space-time codes that asymptotically achieve the transmit diversity bound on DMT for all multiplexing gains and for number of relays N ≥ 2. The distributed space-time codes for all the protocols considered are based on Cyclic Division Algebras (CDA). The second part of the work addresses the DMT analysis of diversity embedded codes for MIMO channels. Diversity embedded codes are high rate codes that are designed so that they have a high diversity code embedded within them. This allows a form of opportunistic communication depending on the channel conditions. The high diversity code ensures that at least a part of the information is received reliably, whereas the embedded high rate code allows additional information to be transferred if the channel is good. This can be thought of coding the data into two streams: high priority and low priority streams so that the high priority stream gets a better reliability than the lower priority stream. We show that superposition based diversity embedded codes in conjunction with naive single stream decoding is sub-optimal in terms of the DM tradeoff. We then construct explicit diversity embedded codes by the superposition of approximately universal space-time codes from CDAs. The relationship between broadcast channels and the diversity embedded setting is then utilized to provide some achievable Diversity Gain Region (DGR) for MIMO broadcast Channels.

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22

Lin, Hung-Wei y 林弘偉. "Gait-Based Action Recognition via Accelerated Minimum Incremental Coding Length Classifier". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/91387776282712365977.

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碩士
國立臺灣大學
資訊工程學研究所
99
In this thesis, we present a novel approach based on the gait energy image (GEI) and the minimum incremental coding length (MICL) for classifying human actions. GEIs are transformed into vectors as input features, and MICL is employed to be the classifier. Moreover, the strategy of majority voting is applied to the MICL classification results to improve the overall system performance. Experimental results show that the proposed approach can achieve approximately 95% of precision, and the classification task can be accomplished in a very short time with the aid of GPU. In other words, the proposed approach can be integrated as a useful component for detecting abnormal events in video surveillance applications.

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23

Gail, Alexander [Verfasser]. "Neuronal basis of perceptual binding processes in visual object coding / by Alexander Gail". 2003. http://d-nb.info/972804749/34.

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24

Raj, Kumar K. "Construction Of High-Rate, Reliable Space-Time Codes". Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1413.

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25

Nikjah, Reza. "Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks". Phd thesis, 2010. http://hdl.handle.net/10048/1674.

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The importance of cooperative relaying communication in substituting for, or complementing, multiantenna systems is described, and a brief literature review is presented. Amplify-and-forward (AF) and decode-and-forward (DF) relaying are investigated and compared for a dual-hop relay channel. The optimal strategy, source and relay optimal power allocation, and maximum cooperative gain are determined for the relay channel. It is shown that while DF relaying is preferable to AF relaying for strong source-relay links, AF relaying leads to more gain for strong source-destination or relay-destination links. Superimposed and selection AF relaying are investigated for multirelay, dual-hop relaying. Selection AF relaying is shown to be globally strictly outage suboptimal. A necessary condition for the selection AF outage optimality, and an upper bound on the probability of this optimality are obtained. A near-optimal power allocation scheme is derived for superimposed AF relaying. The maximum instantaneous rates, outage probabilities, and average capacities of multirelay, dual-hop relaying schemes are obtained for superimposed, selection, and orthogonal DF relaying, each with parallel channel cooperation (PCC) or repetition-based cooperation (RC). It is observed that the PCC over RC gain can be as much as 4 dB for the outage probabilities and 8.5 dB for the average capacities. Increasing the number of relays deteriorates the capacity performance of orthogonal relaying, but improves the performances of the other schemes. The application of rateless codes to DF relaying networks is studied by investigating three single-relay protocols, one of which is new, and three novel, low complexity multirelay protocols for dual-hop networks. The maximum rate and minimum energy per bit and per symbol are derived for the single-relay protocols under a peak power and an average power constraint. The long-term average rate and energy per bit, and relay-to-source usage ratio (RSUR), a new performance measure, are evaluated for the single-relay and multirelay protocols. The new single-relay protocol is the most energy efficient single-relay scheme in most cases. All the multirelay protocols exhibit near-optimal rate performances, but are vastly different in the RSUR. Several future research directions for fixed-rate and rateless coded cooperative systems, and frameworks for comparing these systems, are suggested.
Communications

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