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In this paper, we present a new spectrum-hole prediction model for cognitive radio (CR) systems based on the IEEE 802.11 wireless local areas networks. We have also analyzed the distribution of interval between two consecutive packets (ITCP) based on a simple two-user network. For multiuser networks, we have investigated the distribution of ITCP and study its characteristics using Bayesian inference...
In this paper, we propose an unsupervised method of playfield segmentation for various sport videos. The method first applies local maximum clustering to gather feature samples into several clusters in the Cb-Cr plane. Next, a novel idea is developed to merge clusters into four color classes - Red, Green, Blue and Grey. Finally, a simple scheme of region fusion eliminates small and unimportant areas...
In order to complete maintainability design and prediction in design stage, case based reasoning (CBR), as an artificial intelligence (AI) method, is used in this paper. The maintainability of structure is considered in design stage. So the cases of structure including not only function factors but also maintainability factors are presented by frame. The retrieval algorithm about similar cases is...
Reduction of Single Input Single Output (SISO) discrete systems into Reduced Order Model (ROM), using a conventional and a bio-inspired evolutionary technique is presented in this paper. In the conventional technique, mixed advantages of Modified Cauer Form (MCF) and differentiation are used. In this method, the original discrete system is first converted into equivalent continuous system by applying...
This paper presents an empirical analysis of the performance of differential evolution (DE) variants on different classes of unconstrained global optimization benchmark problems. This analysis has been undertaken to identify competitive DE variants which perform reasonably well on a range of problems with different features. Towards this, fourteen DE variants were implemented and tested on 14 high...
In this paper we present an empirical, comparative performance, analysis of fourteen variants of Differential Evolution (DE) and Dynamic Differential Evolution (DDE) algorithms to solve unconstrained global optimization problems. The aim is to compare DDE, which employs a dynamic evolution mechanism, against DE and to identify the competitive variants which perform reasonably well on problems with...
Differential evolution (DE) is a simple and efficient scheme for global optimization over continuous spaces. DE is generally considered as a reliable, accurate, robust and fast optimization techniques. It outperforms many other optimization algorithms in terms of convergence speed and robustness over common benchmark problems and real world applications. However, the user is required to set the values...
A functional differential inclusion-based approach to L2-gain analysis and feedback control problems is presented for a class of discontinuous time-delay systems. Motivated by Filippov solution in the differential equations with discontinuous right-hand side, definition of the discontinuous time-delay systems forced by external signals is introduced, and a description of L2-gain property in the sense...
In the present study a Modified Differential Evolution (MDE) algorithm is proposed. This algorithm is different in three ways from basic DE. For initialization it utilizes opposition-based learning while in basic DE uniform random numbers serve this task. Secondly, in basic DE mutant individual is random while in MDE it is tournament best and finally MDE utilizes only one set of population as against...
As an effective tool for optimization, differential evolution (DE) has aroused much interest. But the premature convergence of it often gives rise to erroneous results so should be improved. In this paper, a novel differential evolutionary algorithm (DECH) based on chaos local search (CLS) is proposed, which divides DE algorithm into two stages. Firstly, DECH runs with original DE model 'DE/best/1/bin'...
An equivalence between logic algebra and functional dependencies shows that a functional dependency is implied by a set of functional dependencies if and only if its corresponding product term is implied by corresponding logic function. In this paper we shall state and proof a key point ignored for a long time, that is any prime implicate in a corresponding logic function of a set of functional dependencies...
Cognitive radio with spectrum sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, achievable capacity gain of spectrum sharing systems over dynamic fading environments is studied. For the analysis, a theoretical fading model called hyper fading model that is suitable to the dynamic nature of cognitive radio...
The ever-increasing demand for precious radio spectrum along with the inefficient usage of licensed band has led to the advent of the cognitive radio (CR) technology, which aims to provide opportunistic spectrum usage to unlicensed users and thus lead to the co-existence and interference control problem among heterogeneous systems. In this paper, an interference minimization and subcarrier power allocation...
In cognitive radio networks, the CR users have to detect the spectrum channels periodically to make sure that the primary users are absent during their data transmission in order to avoid the collisions to the primary users. Based on the energy detection, the fixed duration of sensing frame can determine the performances of the detection. But, the duration of data transmission frame has an effect...
In this paper, a modified Differential Evolution (MDE) is proposed for solving the Integer Programming problems. In order to increase the probability of each parent to generate a better offspring, each solution is allowed to generate more than one offspring through six different mutation operators. A migration operator is designed to overcome premature convergence of DE. In practical applications,...
The project risks can be evaluated by Analytic Hierarchy Process however this method is not flexible. Based on the introduction of Gray System Theory and the improvement of Analytic Hierarchy Process, Gray Analytic Hierarchy Process was proposed in this paper to evaluate project risks effectively. The basic steps of Gray Analytic Hierarchy Process were given, and the example, using this method to...
In this paper, we propose a novel spectrum sensing technique, called as multi-slot spectrum sensing, to detect spectral holes and to opportunistically use under-utilized frequency bands without causing harmful interference to legacy (primary) networks. The key idea of the proposed sensing scheme is to combine the observations from the past N (N ?? 2) sensing blocks including the latest one. Specifically,...
According to the popular use of digital camera, a traveler group carries multiple cameras for the same event. Previous studies on digital photo focused on massive unrelated photos or collections of a private user. But group travelers can carry several cameras and take photos simultaneously at the same time. Thus, an effective management for group photos is main issue for a traveler group. Since group...
In recent years a new evolutionary algorithm for optimization in continuous spaces called Differential Evolution (DE) has developed. If one wants to apply DE one has to specify several parameters as well as to select a scheme. Several schemes being widely used can be found in literature. This raises the question, which one fits best to your application at hand. To get rid of this scheme selection...
The average utility measure is adopted in this paper to reveal a better utility effect of combining several items than the original utility measure. A mining algorithm is then proposed to efficiently find the high average-utility itemsets. It uses the summation of the maximal utility among the items in each transaction including the target itemset as the upper bounds to overestimate the actual average...
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