Página 1 dos resultados de 6936 itens digitais encontrados em 0.169 segundos

‣ Communication complexity of some problems in distributed computation

Luo, Zhi-Quan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 5, 158 leaves; 12062591 bytes; 12062346 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.21844%
by Zhi-Quan Luo.; Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.; Includes bibliographical references (leaves 153-158).

‣ Multigrid algorithms and complexity results for discrete-time stochastic control and related fixed-point problems

Chow, Chee-Seng
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 162 leaves; 12568038 bytes; 12567794 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.21844%
by Chee-Seng Chow.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.; Includes bibliographical references (leaves 159-162).

‣ An information theoretic study of reduced-complexity receivers for intersymbol interference channels

Abou Faycal, Ibrahim C. (Ibrahim Chafik)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 108 leaves; 5833690 bytes; 5833449 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.626665%
The complexity of the optimal receiver for communications over a discrete-time additive Gaussian intersymbol interference channel typically grows exponentially with the duration of the channel impulse response. Consequently, practical sub-optimal receivers are often designed as though the channel impulse response were shorter than it is. While previous studies on the performance of such receivers have mainly focused on bit error rates in uncoded systems, this thesis takes a different approach to the problem. We adopt an information theoretic approach and study the rates that are achievable in the Shannon sense over the true channel with the given, possibly sub-optimal, decoding rule. One can establish that, under such mismatch conditions, the achievable rates are bounded in the Signal-to-Noise Ratio necessitating the use of a linear equalizer at the front end of the decoder. We derive the achievable rates for these schemes and optimize under complexity constraints the design of the equalizer and the receiver. Overall, two ensemble of codes are considered: the Independent Identically Distributed Gaussian ensemble and the "spherical" ensemble, where codewords are uniformly distributed over a sphere.; by Ibrahim C. Abou Faycal.; Thesis (Ph.D.)--Massachusetts Institute of Technology...

‣ Minimum description complexity

Beheshti, Soosan, 1969-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 140 p.; 9938942 bytes; 9938698 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.48634%
The classical problem of model selection among parametric model sets is considered. The goal is to choose a model set which best represents observed data. The critical task is the choice of a criterion for model set comparison. Pioneer information theoretic based approaches to this problem are Akaike information criterion (AIC) and different forms of minimum description length (MDL). The prior assumption in these methods is that the unknown true model is a member of all the competing sets. We introduce a new method of model selection: minimum description complexity (MDC). The approach is motivated by the Kullback-Leibler information distance. The method suggests choosing the model set for which the model set relative entropy is minimum. We provide a probabilistic method of MDC estimation for a class of parametric model sets. In this calculation the key factor is our prior assumption: unlike the existing methods, no assumption of the true model being a member of the competing model sets is needed. The main strength of the MDC calculation is in its method of extracting information from the observed data.; (cont.) Interesting results exhibit the advantages of MDC over MDL and AIC both theoretically and practically. It is illustrated that...

‣ Property testing : theory and applications

Raskhodnikova, Sofya, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 111 p.; 6735684 bytes; 6749236 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
67.71302%
(cont.) We show upper and lower bounds for the general problem and for specific partial orders. A few of our intermediate results are of independent interest. 1. If strings with a property form a vector space, adaptive 2-sided error tests for the property have no more power than non-adaptive 1-sided error tests. 2. Random LDPC codes with linear distance and constant rate are not locally testable. 3. There exist graphs with many edge-disjoint induced matchings of linear size. In the final part of the thesis, we initiate an investigation of property testing as applied to images. We study visual properties of discretized images represented by n x n matrices of binary pixel values. We obtain algorithms with the number of queries independent of n for several basic properties: being a half-plane, connectedness and convexity.; Property testers are algorithms that distinguish inputs with a given property from those that are far from satisfying the property. Far means that many characters of the input must be changed before the property arises in it. Property testing was introduced by Rubinfeld and Sudan in the context of linearity testing and first studied in a variety of other contexts by Goldreich, Goldwasser and Ron. The query complexity of a property tester is the number of input characters it reads. This thesis is a detailed investigation of properties that are and are not testable with sublinear query complexity. We begin by characterizing properties of strings over the binary alphabet in terms of their formula complexity. Every such property can be represented by a CNF formula. We show that properties of n-bit strings defined by 2CNF formulas are testable with O([square root of]n) queries...

‣ A low-complexity linear and iterative receiver architecture for multi-antenna communication systems

Milliner, David Louis, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 63 leaves; 2709838 bytes; 2715716 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.48634%
Multi-antenna systems have been shown to significantly improve channel capacity in wireless environments. The focus of this thesis is on the design of low-complexity multi-antenna receiver architectures for communication networks and their demonstration in a real-time wireless environment. Our practical realization of an orthogonal frequency-division multi-antenna receiver is capable of several forms of linear and iterative detection. Our implementation is based on a division-free reformulation of standard minimum mean-squared-error detection algorithms and uses complex dot-products as the basic building blocks of a folded-pipelined architecture. This folded-pipelined architecture provides significant area savings over non-folded approaches. The demonstration of our receiver architecture is carried out on a rapid-prototyping FPGA communication system. This prototype is used to validate our design and complement theoretical and simulated results with real-time laboratory measurements in a typical office environment.; by David Louis Milliner.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Vita.; Includes bibliographical references (leaves 60-62).

‣ VISTA : a visualization tool for computer architects; Visualization tool for computer architects

Mihalik, Aaron D. (Aaron Daniel), 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 55 leaves; 3599683 bytes; 3605553 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.732544%
As computer architectures continue to grow in complexity, software developers and hardware engineers cope with the increasing complexity by developing proprietary applications, simulations and tool sets to understand the behavior of these complex systems. Although the field of information visualization is leading to powerful applications in many areas, information visualization applications for computer architecture development are either tightly coupled with a specific architecture or target a wide range of computer system data. This thesis introduces the Visualization Tool for Computer Architects (VISTA) Environment. The VISTA Environment is an extensible and modular information visualization environment for hardware engineers, software developers and educators to visualize data from a variety of computer architecture simulations at different levels of abstraction. The VISTA Environment leverages common attributes in simulation data, computer architecture visualizations, and computer architecture development methods to create a powerful information visualization environment to aid in designing, understanding and communicating complex computer architectures.; by Aaron D. Mihalik.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ A framework for low-complexity iterative interference cancellation in communication systems

Chan, Albert M. (Albert Michael), 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 215 p.; 10260186 bytes; 10290533 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.77152%
Communication over interference channels poses challenges not present for the more traditional additive white Gaussian noise (AWGN) channels. In order to approach the information limits of an interference channel, interference mitigation techniques need to be integrated with channel coding and decoding techniques. This thesis develops such practical schemes when the transmitter has no knowledge of the channel. The interference channel model we use is described by r = Hx + w, where r is the received vector, H is an interference matrix, x is the transmitted vector of data symbols chosen from a finite set, and w is a noise vector. The objective at the receiver is to detect the most likely vector x that was transmitted based on knowledge of r, H, and the statistics of w. Communication contexts in which this general integer programming problem appears include the equalization of intersymbol interference (ISI) channels, the cancellation of multiple-access interference (MAI) in code-division multiple-access (CDMA) systems, and the decoding of multiple-input multiple-output (MIMO) systems in fading environments. We begin by introducing mode-interleaved precoding, a transmitter preceding technique that conditions an interference channel so that the pairwise error probability of any two transmit vectors becomes asymptotically equal to the pairwise error probability of the same vectors over an AWGN channel at the same signal-to-noise ratio (SNR). While mode-interleaved precoding dramatically increases the complexity of exact ML detection...

‣ Interference characterization and suppression for multiuser direct-sequence spread-spectrum system

Fan, Mingxi, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 184 p.; 6539812 bytes; 6539619 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
67.71302%
In this thesis we investigate efficient modulation and detection techniques for the uplink (i.e. transmission from mobile to base station) of a DS-CDMA network. Specifically, the thesis contains three parts. In the first part, we focus on the mobile transmitter. In particular, we evaluate and compare the spectral efficiency of two promising variable rate DS-CDMA transmission techniques, multicode (MCD) and variable-spreading-gain (VSG), under the presence of multiple-access (user-to-user) interferences (MAI) and multipath interferences. The uniqueness of our study is that in bit-error-rate evaluation, instead of approximating the interference as Gaussian noise (which has been done in most of the previous studies), we incorporate both power and distribution of interferences into consideration. We show where the Gaussian assumption may give misleading answers and how our results in these cases are different from those obtained in the past. In part two and three of the thesis, we focus on the base station receiver. Specifically, we present effective joint detection techniques that have good performance-complexity tradeoff. Part two of the thesis introduces a class of novel multistage parallel interference cancellation algorithms based on stage-by-stage minimum mean-squared error (MMSE) optimization. We show that this scheme is capable of achieving significantly better performance than other algorithms with similar complexity. Part three of the thesis presents a low-complexity dual-mode multiuser detector that dynamically switches its detection mode between the matched-filter receiver and the decorrelator. We show that this detector is capable of achieving the performance of a decorrelator but with significant savings in processing power and complexity.; by Mingxi Fan.; Thesis (Ph. D.)--Massachusetts Institute of Technology...

‣ Quantum query complexity revisited

Preda, Daniel C. (Daniel Ciprian), 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 31 leaves; 830033 bytes; 829842 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.21844%
by Daniel C. Preda.; Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.; Includes bibliographical references (leaves 30-31).

‣ Synthesis and evaluation of fault-tolerant quantum computer architectures

Cross, Andrew W. (Andrew William), 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 247 p.; 13338513 bytes; 13370932 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.388984%
Fault-tolerance is the cornerstone of practical, large-scale quantum computing, pushed into its prominent position with heroic theoretical efforts. The fault-tolerance threshold, which is the component failure probability below which arbitrarily reliable quantum computation becomes possible, is one standard quality measure of fault-tolerant designs based on recursive simulation. However, there is a gulf between theoretical achievements and the physical reality and complexity of envisioned quantum computing systems. This thesis takes a step toward bridging that gap. We develop a new experimental method for estimating fault-tolerance thresholds that applies to realistic models of quantum computer architectures, and demonstrate this technique numerically. We clarify a central problem for experimental approaches to fault-tolerance evaluation--namely, distinguishing between potentially optimistic pseudo-thresholds and actual thresholds that determine scalability. Next, we create a system architecture model for the trapped-ion quantum computer, discuss potential layouts, and numerically estimate the fault-tolerance threshold for this system when it is constrained to a local layout. Finally, we place the problem of evaluation and synthesis of fault-tolerant quantum computers into a broader framework by considering a software architecture for quantum computer design.; by Andrew W. Cross.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Throughput and complexity tradeoffs in the multi-antenna downlink

Swannack, Charles (Charles Henry)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 77 p.; 3346386 bytes; 3349522 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.626665%
This thesis considers the joint design of the multiplexing and scheduling of independent data streams for the Gaussian multiple-input multiple-output (MIMO) broadcast channel. It is well known that the use of multiple transmit antennas can greatly increase the capacity of the broadcast channel. However, the complexity of a capacity-achieving strategy is dominated by the underlying search for the best user subset to multiplex across the transmitter array, which can be prohibitively high if the number of users is much greater than the transmit dimension. To reduce this complexity, one can limit the search to a smaller set of users while ensuring that this restricted pool contains a set that is close to optimal with high probability. To this end, we define sets with guaranteed signal to interference ratio (SIR) and signal to noise ratio (SNR) values. We provide bounds on the probability that such a set exists. These bounds are derived through an interpretation of the multi-user multi-antenna channel as a random packing of the unit sphere. As such, we provide refined estimates on the content of spherical caps so that they can be applied as a model for interference. We then employ recent developments in the area of random geometric graph theory to characterize the probability of existence.; (cont.) We further show there is a phase transition phenomenon in channel geometry that can be used in the design of efficient algorithms for scheduling in the MIMO broadcast channel. Further...

‣ Algorithms and lower bounds in finite automata size complexity

Kapoutsis, Christos, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 99 p.
Português
Relevância na Pesquisa
77.21844%
In this thesis we investigate the relative succinctness of several types of finite automata, focusing mainly on the following four basic models: one-way deterministic (1)FAs), one-way nondeterministic (1NFAs), two-way deterministic (2DFAS), and two-way nondeterministic (2NFAS). First, we establish the exact values of the trade-offs for all conversions from two-way to one-way automata. Specifically, we prove that the functions ... return the exact values of the trade-offs from 2DFAS to 1DFAS, from 2NFAS to 1DFAs, and from 2DFAs or 2NFAS to 1NFAs, respectively. Second, we examine the question whether the trade-offs from NFAs or 2NFAS to 2DiFAs are polynomial or not. We prove two theorems for liveness, the complete problem for the conversion from 1NFAS to 2DFAS. We first focus on moles, a restricted class of 2NFAs that includes the polynomially large 1NFAS which solve liveness. We prove that, in contrast, 2DFA moles cannot solve liveness, irrespective of size.; (cont.) We then focus on sweeping 2NFAS, which can change the direction of their input head only on the end-markers. We prove that all sweeping 2NFAs solving the complement of liveness are of exponential size. A simple modification of this argument also proves that the trade-off from 2DFAS to sweeping 2NFAS is exponential. Finally...

‣ Banked microarchitectures for complexity-effective superscalar microprocessors

Tseng, Jessica Hui-Chun, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 99 p.
Português
Relevância na Pesquisa
77.626665%
High performance superscalar microarchitectures exploit instruction-level parallelism (ILP) to improve processor performance by executing instructions out of program order and by speculating on branch instructions. Monolithic centralized structures with global communications, including issue windows and register files, are used to buffer in-flight instructions and to maintain machine state. These structures scale poorly to greater issue widths and deeper pipelines, as they must support simultaneous global accesses from all active instructions. The lack of scalability is exacerbated in future technologies, which have increasing global interconnect delay and a much greater emphasis on reducing both switching and leakage power. However, these fully orthogonal structures are over-engineered for typical use. Banked microarchitectures that consist of multiple interleaved banks of fewer ported cells can significantly reduce power, area, and latency of these structures.; (cont.) Although banked structures exhibit a minor performance penalty, significant reductions in delay and power can potentially be used to increase clock rate and lead to more complexity-effective designs. There are two main contributions in this thesis. First, a speculative control scheme is proposed to simplify the complicated control logic that is involved in managing a less-ported banked register file for high-frequency superscalar processors. Second...

‣ Characterization and computation of equilibria in infinite games

Stein, Noah D. (Noah Daniel)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 82 p.
Português
Relevância na Pesquisa
67.71302%
Broadly, we study continuous games (those with continuous strategy spaces and utility functions) with a view towards computation of equilibria. We cover all of the game-theoretic background needed to understand these results in detail. Then we present new work, which can be divided into three parts. First, it is known that arbitrary continuous games may have arbitrarily complicated equilibria, so we investigate some properties of games with polynomial utility functions and a class of games with polynomial-like utility functions called separable games. We prove new bounds on the complexity of equilibria of separable games in terms of the complexity of the utility functions. In order to measure this complexity we propose a new definition for the rank of a continuous game; when applied to the case of finite games this improves on the results known in that setting. Furthermore, we prove a characterization theorem showing that several conditions which are necessary for a game to possess a finite-dimensional representation each define the class of separable games precisely, providing evidence that separable games are the natural class of continuous games in which to study computation. The characterization theorem also provides a natural connection between separability and the notion of the rank of a game. Second...

‣ Complexity of union-split-find problems

Lai, Katherine Jane
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 46 p.
Português
Relevância na Pesquisa
77.21844%
In this thesis, we investigate various interpretations of the Union-Split-Find problem, an extension of the classic Union-Find problem. In the Union-Split Find problem, we maintain disjoint sets of ordered elements subject to the operations of constructing singleton sets, merging two sets together, splitting a set by partitioning it around a specified value, and finding the set that contains a given element. The different interpretations of this problem arise from the different assumptions made regarding when sets can be merged and any special properties the sets may have. We define and analyze the Interval, Cyclic, Ordered, and General Union-Split-Find problems. Previous work implies optimal solutions to the Interval and Ordered Union-Split-Find problems and an (log n/ log log n) lower bound for the Cyclic Union-Split-Find problem in the cell-probe model. We present a new data structure that achieves a matching upper bound of (log n/ log log n) for Cyclic Union-Split Find in the word RAM model. For General Union-Split-Find, no o(n) bound is known. We present a data structure which has an [Omega](log2 n) amortized lower bound in the worst case that we conjecture has polylogarithmic amortized performance. This thesis is the product of joint work with Erik Demaine.; by Katherine Jane Lai.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Communication Complexity

Hauser, George J.
Fonte: University of Rochester. Computer Science Department. Publicador: University of Rochester. Computer Science Department.
Tipo: Relatório
Português
Relevância na Pesquisa
67.71931%
Ph.D. Thesis, Computer Science Dept., U. Rochester, Gary L. Peterson, thesis advisor; simultaneously published in the Technical Reprt series; A complete and formal model of computation for a network of two communicating processes is presented which uses an extension of the Turing Machine called a Communicating Turing Machine (CTM). The resources of number of symbols exchanged and maximum amount of local storage used between messages are identified and referred to as the communication time and communication space respectively. As a pair of processors, each with its own input, a fortiori accepts a set of pairs of strings, some consideration must be given to the mapping of problems to CTM inputs. A model parameter is this input mapping function. In addition to consideration of the usual partition mapping, we introduce a distribution mapping which bounds only the number of fragments into which an input is divided, and all partitions with this fragmentation are allowed. Complexity classes for each input mapping function are identified. A full, dense hierarchy is shown to exist in communication space and time from constant up to linear. For distribution input mappings, it is shown that the constant complexity classes are exactly the regular languages and that there is a gap between constant and log log n in the space hierarchy. For fair partition input mappings most of the structure of standard TM complexity obtains for Communication Complexity. An upper bound is given for the communication space complexity of Context Free languages and it is shown that the bound is met for bounded-fragmentation partitions. Example languages demonstrate that most complexity class relationships under fair partitions cannot be improved. An algorithm is presented that optimizes the communication time complexity of an existing communication protocol for a finite language. A new lower bound for communication complexity is presented which uses the number of equivalence classes of strings induced by the language and the input mapping function independently. It is shown that this lower bound is within a constant factor of the required minimum for communication time on fixed-cut partition input mappings.

‣ Locally Decodable Codes and Private Information Retrieval Schemes; LDCs and PIRs

Yekhanin, Sergey
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 99 leaves
Português
Relevância na Pesquisa
67.81377%
This thesis studies two closely related notions, namely Locally Decodable Codes (LDCs) and Private Information Retrieval Schemes (PIRs). Locally decodable codes are error-correcting codes that allow extremely efficient, "sublinear-time" decoding procedures. More formally, a k-query locally decodable code encodes n-bit messages x in such a way that one can probabilistically recover any bit xi of the message by querying only k bits of the (possibly corrupted) code-word, where k can be as small as 2. LDCs were initially introduced in complexity theory in the context of worst-case to average-case reductions and probabilistically checkable proofs. Later they have found applications in numerous other areas including information theory, cryptography and the theory of fault tolerant computation. The major goal of LDC related research is to establish the optimal trade-off between length N and query complexity k of such codes, for a given message length n. Private information retrieval schemes are cryptographic protocols developed in order to protect the privacy of the user's query, when accessing a public database. In such schemes a database (modelled by an n-bit string x) is replicated between k non-communicating servers. The user holds an index i and is interested in obtaining the value of the bit xi. To achieve this goal...

‣ Low-complexity approaches to distributed data dissemination

Coleman, Todd P. (Todd Prentice), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 173 p.; 880283 bytes; 892151 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.626665%
In this thesis we consider practical ways of disseminating information from multiple senders to multiple receivers in an optimal or provably close-to-optimal fashion. The basis for our discussion of optimal transmission of information is mostly information theoretic - but the methods that we apply to do so in a low-complexity fashion draw from a number of different engineering disciplines. The three canonical multiple-input, multiple-output problems we focus our attention upon are: * The Slepian-Wolf problem where multiple correlated sources must be distributedly compressed and recovered with a common receiver. * The discrete memoryless multiple access problem where multiple senders communicate across a common channel to a single receiver. * The deterministic broadcast channel problem where multiple messages are sent from a common sender to multiple receivers through a deterministic medium. Chapter 1 serves as an introduction and provides models, definitions, and a discussion of barriers between theory and practice for the three canonical data dissemination problems we will discuss. Here we also discuss how these three problems are all in different senses 'dual' to each other, and use this as a motivating force to attack them with unifying themes.; (cont.) Chapter 2 discusses the Slepian-Wolf problem of distributed near-lossless compression of correlated sources. Here we consider embedding any achievable rate in an M-source problem to a corner point in a 2M - 1-source problem. This allows us to employ practical iterative decoding techniques and achieve rates near the boundary with legitimate empirical performance. Both synthetic data and real correlated data from sensors at the International Space Station are used to successfully test our approach. Chapter 3 generalizes the investigation of practical and provably good decoding algorithms for multiterminal systems to the case where the statistical distribution of the memoryless system is unknown. It has been well-established in the theoretical literature that such 'universal' decoders exist and do not suffer a performance penalty...

‣ Representing and analyzing temporal complexity in children's story books

Scheidegger, Madleina C
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 82 leaves; 4460152 bytes; 4463504 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
77.81377%
In this thesis, the temporal complexity in children's stories is analyzed to better understand the development of children's perception of time. The temporal complexity increases both in greater deviations from a chronological presentation of events, as well as an increase in the different kinds of temporal relations between events. Tools to analyze and display the temporal complexity were developed and are used to demonstrate an increase in temporal complexity as the grade level increases. The results from this were then used to determine the appropriate reading material for a given grade of sample stories. Unlike the normal assessments methods, that use only the word and sentence complexity, this thesis takes into account both the the semantic contents of the story and the cognitive ability of the child.; by Madleina C. Scheidegger.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Includes bibliographical references (leaves 81-82).