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Network virtualization has been proposed as a powerful vehicle for running multiple customized networks on a shared infrastructure. Virtual network embedding is a critical step for network virtualization that deals with efficient mapping of virtual nodes and virtual links onto the substrate network resources. Previous work in virtual network embedding primarily focused on designing heuristic algorithms...
Motion estimation plays an important role in inter-frame prediction for the video coding standards such as H.264/AVC, MPEG-2, MPEG-4, VC-1, and so on. Its huge computation complexity, however, makes it difficult to achieve real-time coding for the HDTV1080p. In this paper, we propose a dynamic search range algorithm which reduces about 80% of search points in full search algorithm for the H.264/AVC...
In a multihomed video streaming system, a video sequence is simultaneously transmitted over multiple access networks to a client. In this paper, we formulate the rate control and stream adaptation problems into a unified optimization problem, which determines the sending rates of individual networks, selects which video packets to transmit, and assigns each packet to an access network. We propose...
Improving latency is the key to a successful online game-playing experience. With the use of multiple servers along with a well-provisioned network it is possible to reduce the latency. Given a network of servers, game clients, and a desired delay bound, we have designed algorithms to determine the subnetwork of servers whose cardinality is minimal. We have considered the cases wherein the subnetwork...
We study the dynamic bid optimization problem via a primal dual approach. In the case we have no information about the distribution of queries, we reconstruct the ln(U/L) + 1 competitive algorithm proposed in [ZCL08] through a systematic way and showed the intuition behind this algorithm. In the case of random permutation model, we showed that the learning technique used in [DH09] can give us a (1...
In this paper, we present a new heuristic that generates broadcast schemes in arbitrary networks. The heuristic gives optimal broadcast time for ring, tree and grid if the originator is on the corner. Extensive simulations show that our new heuristic outperforms the best known broadcast algorithms for two different network models representing Internet and ATM networks. It also allows to generate broadcast...
In this paper, we proposed a hybrid algorithm to solve unit commitment optimization problem, which is composed of operation ant colony optimization (ACO) algorithm and Lambda-iteration method. By means of operation encoding, space complexity of ACO algorithm for solving UCP is reduced. Moreover, space complexity can be regulated by adjusting the number of maximum allowable operation in a single time...
Motion estimation is the most computationally intensive part in a typical video encoder. This paper introduces a novel prediction method based on multiple search centers, which can efficiently improve the prediction accuracy. According to the amount and the magnitude of predictive search centers, the search range is dynamically adjusted in order to reduce the computational complexity. Based on multiple...
Compact representation of integer values is a key feature for data compression. A compressed representation allows us to store more integers within less space, and therefore, to work in faster hierarchies of memory. Adaptive searching yields to compressed representations of integers. In scenarios where the cost of updating the encoding is high, approaches to perform operations over integers dynamically...
Scaling frequency and voltage in a coordinated manner is a promising way to reduce energy and power. we explore the use of dynamic frequency clocking within the datapath and datapath scheduling algorithms that can be incorporated into a datapath synthesis tool. Given a schedule, we propose a practical optimal frequency assignment algorithm based on dynamic programming. The algorithm run very fast...
Web services composition (WSC) is the key techniques in its application. Dynamically selecting reliable Web services (WSs) becomes crucial to users. In fact, most works regard a Web service (WS) as the basic unit and selection with end-to-end, and as more and more WSs become available, the WSs selection problem is a complex NP-hard optimization problem. So, in this paper, the WSs consist of the operations...
The research presented here focuses on a Phonetic Search method used in long speech utterances using a very large vocabulary of words. Our main goal was to reduce the search space dimension and thus decrease the overall computational complexity without adversely affecting the recognition performance. The suggested method was compared to the Exhaustive Search method in which all possible hypotheses...
The generalized assignment problem is a well-known NP-complete problem whose objective is to find a minimum cost assignment of a set of jobs to a set of agents by considering the resource constraints. Dynamic instances of the generalized assignment problem can be created by changing the resource consumptions, capacity constraints and costs of jobs. Memory-based approaches are among a set of evolutionary...
Traditional multicast technology faces a serious state scalability problem when there are large numbers of concurrent groups in the network. As a new approach to solve this scalability problem, aggregated multicast forces multiple multicast groups to share a common distribution tree. This can be defined as a minimum grouping problem and is proved to be an NPC problem. An ant colony optimization algorithm...
We present fast adaptive parallel algorithms to compute the sum of N Gaussians at N points. Direct sequential computation of this sum would take O(N2) time. The parallel time complexity estimates for our algorithms are O (N/np) for uniform point distributions and O (N/np log N/+ np log np ) for nonuniform distributions using np CPUs. We incorporate a planewave representation of the Gaussian kernel...
The attribute reduction is a core theory of the rough set theory. It has been proven that computing the optimal reduction of decision table is a NP-hard problem. In the paper here, the application of rough entropy in rough sets theory is analyzed, the uncertainty measure of the importance of attribute in decision table is proposed, then, a heuristic algorithm based on rough entropy for reduction of...
Ohya and Volovich found the quantum algorithm with a chaos dynamics, called the OV SAT algorithm which enabled to solve NP-Complete problem in polynomial time. It is proved that the unitary operator of the quantum algorithm can be constructed by a product of so called fundamental gates. To discuss the computational complexity rigorously, we introduced a generalized quantum Turing machine(GQTM) where...
In a structured peer-to-peer (p2p) network, key based routing algorithms are used for searching and locating resources in the network. For dynamic and scalable behavior these algorithms suffer from high overhead to maintain large state information of nodes and to keep them up-to-date. To deal with this problem, a Sub-ring Based Chord model and a lookup algorithm are proposed. The lookup process keeps...
Scalable video coding (SVC), together with adaptive modulation and coding (AMC), can improve wireless multicast streaming video by jointly performing radio resource allocation and modulation and coding scheme (MCS) selection. However, the existing schemes in the literature allocate radio resources for different video layers separately, which leads to a waste of radio resources. In this work, we introduce...
We present a near-linear time algorithm that approximates the edit distance between two strings within a polylogarithmic factor. For strings of length n and every fixed ε >; 0, the algorithm computes a (log n)O(1/ε) approximation in n1+ε time. This is an exponential improvement over the previously known approximation factor, 2Õ(√log n), with a comparable running time [Ostrovsky and Rabani, J....
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