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A PAPR Reduction Scheme for SFBC MIMO-OFDM SystemsTsai, Kun-Han 11 August 2009 (has links)
In multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system which was used space frequency block coding (SFBC) method. It order to reduce the peak-to-average power ratio in several transmit antennas. We proposed two new architectures to simply the computational complexity on transmitter. According to the characteristics of SFBC structure which have M transmitter antennas. We can decomposed the interleaving subcarrier groups by used conversion vector to circular convolution with signal vector and shrink the inverse fast Fourier transform (IFFT) points. Therefore it can do the SFBC coding operation in time domain. By using combination of different cyclic shifts and phase rotations in U subcarrier groups can generate the P candidate signals. And it wouldn¡¦t increase the number of IFFT. The proposed transmitter architectures can improve the major drawback of high computational complexity in traditional selected mapping (SLM). The traditional SLM generate the P candidate signals needs MP IFFT units. Then in the condition of lose a little PAPR reduction performance, we can save the most of computational complexity.
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Circular colorings and acyclic choosability of graphsRoussel, Nicolas 23 December 2009 (has links)
Abstract: This thesis studies five kinds of graph colorings: the circular coloring,
the total coloring, the (d; 1)-total labeling, the circular (r; 1)-total labeling, and the
acyclic list coloring.
We give upper bounds on the circular chromatic number of graphs with small
maximum average degree, mad for short. It is proved that if mad(G)<22=9 then G
has a 11=4-circular coloring, if mad(G) < 5=2 then G has a 14=5-circular coloring.
A conjecture by Behzad and Vizing implies that £G+2 colors are always sufficient
for a total coloring of graphs with maximum degree £G. The only open case for planar graphs is for £G = 6. Let G be a planar in which no vertex is contained in cycles of all lengths between 3 and 8. If £G(G) = 6, then G is total 8-colorable. If £G(G) = 8, then G is total 9-colorable.
Havet and Yu [23] conjectured that every subcubic graph G ̸=K4 has (2; 1)-total
number at most 5. We confirm the conjecture for graphs with maximum average
degree less than 7=3 and for flower snarks.
We introduce the circular (r; 1)-total labeling. As a relaxation of the aforementioned
conjecture, we conjecture that every subcubic graph has circular (2; 1)-total number at most 7. We confirm the conjecture for graphs with maximum average degree less than 5=2.
We prove that every planar graph with no cycles of lengths 4, 7 and 8 is acyclically
4-choosable. Combined with recent results, this implies that every planar
graph with no cycles of length 4;k; l with 5 6 k < l 6 8 is acyclically 4-choosable.
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Thermal dispersion and convective heat transfer during laminar pulsating flow in porous mediaPathak, Mihir Gaurang 28 June 2010 (has links)
Solid-fluid thermal interactions during unsteady flow in porous media play an important role in the regenerators of pulse tube cryocoolers. Pore-level thermal processes in porous media under unsteady flow conditions are poorly understood. The objective of this investigation is to study the pore-level thermal phenomena during pulsating flow through a generic, two-dimensional porous medium by numerical analysis. Furthermore, an examination of the effects of flow pulsations on the thermal dispersion and heat transfer coefficient that are encountered in the standard, volume-average energy equations for porous media are carried out. The investigated porous media are periodic arrays of square cylinders. Detailed numerical data for the porosity range of 0.64 to 0.84, with flow Reynold's numbers from 0-1000 are obtained. Based on these numerical data, the instantaneous as well as cycle-average thermal dispersion and heat transfer coefficients, to be used in the standard unsteady volume-average energy conservation equations for flow in porous media, are derived. Also, the adequacy of current applied cycle-average correlations for heat transfer coefficients and the inclusion of the thermal dispersion in the definition of an effective fluid thermal conductivity are investigated.
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Errors In Delay Differentiation In Statistical MultiplexingMallesh, K 05 1900 (has links)
Different applications of communication networks have different requirements that depend on the type of application. We consider the problem of differentiating between delay-sensitive applications based on their average delay requirements, as may be of interest in signalling networks. We consider packets of different classes that are to be transmitted on the same link with different average delay requirements, to reside in separate queues with the arrival statistics for the queues being specified. This statistical multiplexer has to schedule packets from different queues in so that the average delays of the queues approach the specified target delays as quickly as possible.
For simplicity, we initially consider a discrete-time model with two queues and a single work-conserving server, with independent Bernoulli packet arrivals and unit packet service times. With arrival rates specified, achieving mean queue lengths in a ratio which corresponds to the ratio of target mean delays is a means of achieving individual target mean delays. We formulate the problem in the framework of Markov decision theory. We study two scheduling policies called Queue Length Balancing and Delay Balancing respectively, and show through numerical computation that the expectation of magnitude of relative error in θ (1/m) and θ (1/√m) respectively, and that the expectation of the magnitude of relative error in weighted average delays decays as θ (1/√m) and θ (1/m) respectively, where m is the averaging interval length.
We then consider the model for an arbitrary number of queues each with i.i.d. batch arrivals, and analyse the errors in the average delays of individual queues. We assume that the fifth moment of busy period is finite for this model. We show that the expectation of the absolute value of error in average queue length for at least one of the queues decays at least as slowly as θ (1/√m), and that the mean squared error in queue length for at least one of the queues decays at least as slowly as θ (1/m). We show that the expectation of the absolute value of error in approximating Little’s law for finite horizon is 0 (1/m). Hence, we show that the mean squared error in delay for at least one of the queues decays at least slowly as θ (1/m). We also show that if the variance of error in delay decays for each queue, then the expectation of the absolute value of error in delay for at least one of the queues decays at least as slowly as θ (1/√m).
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Energy and transient power minimization during behavioral synthesis [electronic resource] / by Saraju P Mohanty.Mohanty, Saraju P. January 2003 (has links)
Includes vita. / Title from PDF of title page. / Document formatted into pages; contains 289 pages. / Thesis (Ph.D.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The proliferation of portable systems and mobile computing platforms has increased the need for the design of low power consuming integrated circuits. The increase in chip density and clock frequencies due to technology advances has made low power design a critical issue. Low power design is further driven by several other factors such as thermal considerations and environmental concerns. In low-power design for battery driven portable applications, the reduction of peak power, peak power differential, average power and energy are equally important. In this dissertation, we propose a framework for the reduction of these parameters through datapath scheduling at behavioral level. Several ILP based and heuristic based scheduling schemes are developed for datapath synthesis assuming : (i) single supply voltage and single frequency (SVSF), (ii) multiple supply voltages and dynamic frequency clocking (MVDFC), and (iii) multiple supply voltages and multicycling (MVMC). / ABSTRACT: The scheduling schemes attempt to minimize : (i) energy, (ii) energy delay product, (iii) peak power, (iv) simultaneous peak power and average power, (v) simultaneous peak power, average power, peak power differential and energy, and (vi) power fluctuation. A new parameter called "Cycle Power Function" CPF) is defined which captures the transient power characteristics as the equally weighted sum of normalized mean cycle power and normalized mean cycle differential power. Minimizing this parameter using multiple supply voltages and dynamic frequency clocking results in the reduction of both energy and transient power. The cycle differential power can be modeled as either the absolute deviation from the average power or as the cycle-to-cycle power gradient. The switching activity information is obtained from behavioral simulations. Power fluctuation is modeled as the cycle-to-cycle power gradient and to reduce fluctuation the mean power gradient MPG is minimized. / ABSTRACT: The power models take into consideration the effect of switching activity on the power consumption of the functional units. Experimental results for selected high-level synthesis benchmark circuits under different constraints indicate that significant reductions in power, energy and energy delay product can be obtained and that the MVDFC and MVMC schemes yield better power reduction compared to the SVSF scheme. Several application specific VLSI circuits were designed and implemented for digital watermarking of images. Digital watermarking is the process that embeds data called a watermark into a multimedia object such that the watermark can be detected or extracted later to make an assertion about the object. / ABSTRACT: A class of VLSI architectures were proposed for various watermarking algorithms : (i) spatial domain invisible-robust watermarking scheme, (ii) spatial domain invisible-fragile watermarking scheme, (iii) spatial domain visible watermarking scheme, (iv) DCT domain invisible-robust watermarking scheme, and (v) DCT domain visible watermarking scheme. Prototype implementation of (i), (ii) and (iii) are given. The hardware modules can be incorporated in a "JPEG encoder" or in a "digital still camera". / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
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A reinforcement learning approach to obtain treatment strategies in sequential medical decision problems [electronic resource] / by Radhika Poolla.Poolla, Radhika. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 104 pages. / Thesis (M.S.I.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Medical decision problems are extremely complex owing to their dynamic nature, large number of variable factors, and the associated uncertainty. Decision support technology entered the medical field long after other areas such as the airline industry and the manufacturing industry. Yet, it is rapidly becoming an indispensable tool in medical decision making problems including the class of sequential decision problems. In these problems, physicians decide on a treatment plan that optimizes a benefit measure such as the treatment cost, and the quality of life of the patient. The last decade saw the emergence of many decision support applications in medicine. However, the existing models have limited applications to decision problems with very few states and actions. An urgent need is being felt by the medical research community to expand the applications to more complex dynamic problems with large state and action spaces. / ABSTRACT: This thesis proposes a methodology which models the class of sequential medical decision problems as a Markov decision process, and solves the model using a simulation based reinforcement learning (RL) algorithm. Such a methodology is capable of obtaining near optimal treatment strategies for problems with large state and action spaces. This methodology overcomes, to a large extent, the computational complexity of the value-iteration and policy-iteration algorithms of dynamic programming. An average reward reinforcement-learning algorithm is developed. The algorithm is applied on a sample problem of treating hereditary spherocytosis. The application demonstrates the ability of the proposed methodology to obtain effective treatment strategies for sequential medical decision problems. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
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分析失去部分訊息的貝氏更新計算方法 / Bayesian updating methods for the analysis of censored data.范靜宜, Fan, Gin-Yi Unknown Date (has links)
對於使用貝氏法來處理部份區分(partially-classified)或是失去部分訊息資料的類別抽樣(categorical sampling with censored data),大多建立在「誠實回答」(truthful reporting)以及「無價值性失去部分訊息」(non-informative censoring)的前提下。Jiang(1995)及Jiang and Dickey(2006)取消以上兩個限制,提出貝氏解並利用準貝氏法(quasi-Bayes)來求近似解,而Jiang and Ko(2004)也利用吉氏取樣器(Gibbs sampler)來近似這類問題的貝氏解。本文首先嘗試利用Kuroda, Geng and Niki(2001)所提的“平均變異數和(average variance sum)”估計法
來應用到我們問題的貝氏解。在小樣本時,數值上我們可求得貝氏解,因此本文另一個重點為在小樣本時比較以上三種方法估計值的準確性,並考慮先驗參數(prior)的選取對估計的影響。
本文更進一步證明若選取到某種特殊的先驗參數時,利用“平均變異數和”的方法所計算出來的結果會和
準貝氏法的估計結果相同,而且皆等於用貝氏法計算出的結果。
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Parabolische Randanfangswertaufgaben mit zufälliger Anfangs- und RandbedingungKandler, Anne 08 May 2007 (has links) (PDF)
Die vorliegende Arbeit beschäftigt sich mit dem Problem der
zufälligen Wärmeausbreitung in beschränkten Gebieten. Dieses
Phänomen wird dabei durch eine lineare parabolische
Randanfangswertaufabe beschrieben, wobei die Anfangsbedingung und
die Neumannrandbedingung als zufällige Felder mit gegebener
Wahrscheinlichkeitsverteilung angenommen werden. Des Weiteren werden
die zufälligen Felder als homogen und epsilon-korreliert mit
einer kleinen Korrelationslänge epsilon > 0 vorausgesetzt und
sollen glatte Realisierungen besitzen.
Zur Lösung der Randanfangswertaufgabe werden sowohl die klassische
Formulierung als auch die Variationsformulierung herangezogen und in
diesem Zusammenhang die Fourier Methode sowie die Finite-Elemente
Methode betrachtet. Die Finite-Elemente Methode und die
Fourier-Methode führen auf einen expliziten funktionalen
Zusammenhang zwischen der zufälligen Lösung der betrachteten
Randanfangswertaufgabe und den Einflussgrößen, so dass
Momentenfunktionen davon abgeleitet werden können.
Das Hauptinteresse dieser Arbeit liegt auf der Berechnung dieser
Momentenfunktionen, welche durch die gewählten Eigenschaften der
stochastischen Einflußgrößen bestimmt werden. Basierend auf dem
Finite-Elemente Ansatz bzw. dem Fourier Ansatz werden verschiedene
Approximationsmöglichkeiten insbesondere für die
Korrelationsfunktion erörtert. Des Weiteren wird die Möglichkeit der
Simulation des zufälligen Randanfangswertproblems betrachtet. Hierzu
wird zur Simulation der zufälligen Einflussgrößen auf die Theorie
von Moving Average Feldern zurückgegriffen.
Der letzte Teil der Arbeit widmet sich dem Vergleich der erhaltenen
analytischen Resultate anhand konkreter numerischer Beispiele.
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A CUSUM test for discrete monitoring of intensity of a Poisson processEger, Karl-Heinz 13 June 2010 (has links) (PDF)
This paper deals with CUSUM tests for monitoring
of intensity parameter of a Poisson process if this
process can be observed in a restricted manner only at pregiven
equidistant time points. In this case the process can
be monitored by means of a CUSUM test for the parameter
of a corresponding Poisson distribution.
For rational reference parameter values the computation
of average run length is reduced to that of solving of a
system of simultaneous linear equations. The performance
of obtained CUSUM tests is discussed by means of corresponding
examples.
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Är vi alla beroende av svart guld? : En eventstudie av reaktionen på företags avkastning vid signifikanta oljeprisförändringarAjamlou, Pauline, Cederfelt, Elin January 2015 (has links)
Syfte: Syftet med denna uppsats är att undersöka hur utvalda bolags aktieavkastning inom branscherna flyg, fordon samt olja reagerar vid signifikanta oljeprisförändringar. Teoretiskt perspektiv: Den teoretiska referensramen utgörs av den effektiva marknadshypotesen samt Behavioural Finance med undergrenarna prospect theory, herd behaviour och overconfidence. Metod: Studien utgår ifrån ett deduktivt inslag med en kvantitativ studie. Undersökningen utgörs av sex eventstudier som datainsamlingsmetod samt en intervju som applikation på det kvantitativa resultatet. Urvalskriterium består av tio bolag inom respektive bransch med en rangordning utefter högst omsättning samt företag med en koppling till svenskt näringsliv med högst omsättning. Empiri: Empirin presenteras utifrån diagram och tabeller över de utförda eventstudierna. Diagrammen syftar till att redovisa den avvikande avkastningen för respektive bolag. Tabellerna ger en redogörelse över eventuellt samband mellan respektive bransch och oljeprisförändringarna. Slutsats: Flygbolagen uppvisade samband med oljepriset vid fyra utav sex eventen. Fordonsbranschen uppvisade samband vid ett av de sex eventen och oljebranschen vid två utav de studerade eventen. Reaktionen på aktieavkastningen för bolagen med en koppling till svenskt näringsliv var i linje med de övriga internationella bolagen i branschen. Undantag visades för oljebranschen. Resultatet är en indikation på att andra variabler påverkade aktieavkastningen och detta skapar svårigheter för aktieinnehavare att förespå framtida avkastning.
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