Web 2.0 has been becoming the new tendency of the Internet development. In order to get better management of web 2.0 network resource and guarantee of service quality, the architecture and the advantages of web 2.0 ov...
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Web 2.0 has been becoming the new tendency of the Internet development. In order to get better management of web 2.0 network resource and guarantee of service quality, the architecture and the advantages of web 2.0 over Ajax technology is analyzed, and the impact of Ajax on bandwidth performance of web application is discussed.
This paper discusses the importance of the classification of short message, and details some key technologies related. Through implementing a fundamental prototype, some basic models and technical references are provi...
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This paper discusses the importance of the classification of short message, and details some key technologies related. Through implementing a fundamental prototype, some basic models and technical references are provided.
3D visualization of large-scale virtual crowds is a very important and interesting problem in research fields of virtual reality. For reasons of efficiency and visual realism, it is very difficult to populate, animate...
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3D visualization of large-scale virtual crowds is a very important and interesting problem in research fields of virtual reality. For reasons of efficiency and visual realism, it is very difficult to populate, animate and render large-scale virtual crowds with hundreds of thousand individually animated virtual characters in real-time applications;especially for the scene which has more than ten thousands of individuals with different shapes and motions. In this paper, an efficient method to visualize large-scale virtual crowds is presented. Firstly, using model variation technique, many different models can be derived from a small number of model templates. Secondly, the crowds can be animated individually by deforming a small number of elements in motion database. Thirdly, using a developed point sample rendering algorithm, large-scale crowds can be displayed in real-time. This method can be used to visualize different dynamic crowds which require both real-time efficiency and large number of virtual individuals support. Based on this work, an efficient and readily usable 3D visualization system is presented. It can provide very high visual realism for large crowds' visualization in interactive frame rates on a regular PC. The 3D visualization of 60000 people evacuating from a building is also realized in real-time based on the system.
Topic models have been successfully used to information classification and retrieval. These models can capture word correlations in a collection of textual documents with a low-dimensional set of multinomial distribut...
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Topic models have been successfully used to information classification and retrieval. These models can capture word correlations in a collection of textual documents with a low-dimensional set of multinomial distribution, called "topics". It is important but difficult to select an appropriate number of topics for a specific dataset. This paper proposes a theorem that the model reaches optimum as the average similarity among topics reaches minimum, and based on this theorem, proposes a method of adaptively selecting the best LDA model based on density. Experiments show that the proposed method can achieve performance matching the best of LDA without manually tuning the number of topics.
The limit behaviors of computations have not been fully *** is necessary to consider such limit behaviors when we consider the properties of infinite objects in computer science,such as infinite logic programs,the sym...
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The limit behaviors of computations have not been fully *** is necessary to consider such limit behaviors when we consider the properties of infinite objects in computer science,such as infinite logic programs,the symbolic solutions of infinite polynomial ***,we can use finite objects to approximate infinite objects,and we should know what kinds of infinite objects are approximable and how to approximate them effectively.A sequence {Rκ:κω}of term rewriting systems has the well limit behavior if under the condition that the sequence has the Set-theoretic limit or the distance-based limit,the sequence {Th(Rκ):κ∈ω} of corresponding theoretic closures of Rκ has the set-theoretic or distance-based limit,and limκ→∞ Th(Rκ) is equal to the theoretic closure of the limit of {Rκ:κ∈ω).Two kinds of limits of term rewriting systems are considered:one is based on the set-theoretic limit,the other is on the distance-based *** is proved thatgiven a sequence {Rκ:κ∈ω) of term rewriting systems Rκ,if there is a well-founded ordering (-＜) on terms such that every Rκ is (-＜)-well-founded,and the set-theoretic limit of {Rκ:κ∈ω).exists,then {Rκ:κ∈ω).has the well limit behavior;and if (1) there is a well-founded ordering(-＜)on terms such that every Rκ is(-＜-well-founded,(2) there is a distance d on terms which is closed under substitutions and contexts and (3) {Rκ:κ∈ω).is Cauchy under d then {Rκ:κ∈ω).has the well limit *** results are used to approximate the least Herbrand models of infinite Horn logic programs and real Horn logic programs,and the solutions and Cr(o)bner bases of (infinite) sets of real polynomials by sequences of (finite) sets of rational polynomials.
A novel sequential Monte Carlo （SMC） algorithm is provided for the multiple maneuvering Ad-hoc network terminals direction of arrival （DOA） tracking. A nonlinear mobility and observation model is adopted, which ca...
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A novel sequential Monte Carlo （SMC） algorithm is provided for the multiple maneuvering Ad-hoc network terminals direction of arrival （DOA） tracking. A nonlinear mobility and observation model is adopted, which can describe the motion features of the Ad-hoc network terminal more practically. The algorithm does not need any additional measurement equipment. Simulation result shows its significant tracking accuracy.
A new class of loosely synchronous(LS)spreading sequences with zero correlation window(ZCW)was *** was constructed by making Kronecker product of orthogonal matrix and ZCW complementary *** new LS sequence increases t...
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A new class of loosely synchronous(LS)spreading sequences with zero correlation window(ZCW)was *** was constructed by making Kronecker product of orthogonal matrix and ZCW complementary *** new LS sequence increases the number of perfect complementary pairs and extends ZCW within the same ***,both auto-correlation and cross-correlation of ZCW in the same group remain *** minimum ZCW among different groups is the same as that of basic LS *** method for constructing these new LS sequences is presented and ZCW properties are also *** number of these new LS sequences is only smaller than theoretical upper bound by one.
In this paper, the non-regenerative MIMO-OFDM multi-hop relay system is considered. The non-regenerative approach is the amplify and forward (AF) approach where the relay amplifies and retransmits the signal received ...
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In this paper, the non-regenerative MIMO-OFDM multi-hop relay system is considered. The non-regenerative approach is the amplify and forward (AF) approach where the relay amplifies and retransmits the signal received from the source, furthermore we assume that the relay is allowed to reassign the input sub-channels to the corresponding output sub-channels in space and frequency domain. Power allocation scheme with sub-channel reassignment is developed under a certain power constraint at the relay to achieve the maximum channel capacity. Numerical results indicate that the proposed power allocation scheme achieves a higher system capacity compared with uniform power allocation (UPA) scheme and the optimal power allocation (OPA) scheme without sub-channel reassignment, moreover, the position of relay affects the system performance directly.
To utilize the idle spectrum of licensed system, cognitive radio network should perform reliable and efficient spectrum sensing. Cooperative spectrum sensing has been proposed to combat the channel fading suffered by ...
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To utilize the idle spectrum of licensed system, cognitive radio network should perform reliable and efficient spectrum sensing. Cooperative spectrum sensing has been proposed to combat the channel fading suffered by each individual radio, which improves the detection probability remarkably and mitigates the sensing requirements on individual radios. This paper investigates the optimization problem of detection efficiency of cooperative detection, and proposes an algorithm to evaluate the required number of cooperative radios and length of detection time for the maximal detection efficiency. To show the effect of cooperation and its efficiency, the algorithm is applied to the detection under fading channel using energy detector and spectral correlation detector.
In this paper we focus our research on a fast and reliable technique for timing and frequency synchronization in orthogonal frequency division multiplexing (OFDM) systems using a burst mode transmission. In the propos...
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In this paper we focus our research on a fast and reliable technique for timing and frequency synchronization in orthogonal frequency division multiplexing (OFDM) systems using a burst mode transmission. In the proposed method, we use two constant amplitude zero auto correlation (CAZAC) sequences in the preamble. From analysis, the CAZAC sequence-based preamble gives better detection properties in terms of higher right timing detection probability and accurate fractional frequency synchronization even at a low SNR and in a multipath fading channel. The integral frequency offset can be obtained in time domain. Furthermore, the proposed method can be directly extended to multiple-input multiple-output (MIMO) systems.
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