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Existing clustering techniques primarily rely on prior knowledge about the data, such as the number of clusters and radii. However, in real applications, the number of clusters and the radii of clusters are usually unknown. Therefore, the performance of clustering methods with overlapping data is degraded due to their limitations in finding all cluster centers with uneven density values. Hence, a...
Online shopping has become an essential part of our life, which provides a suitable, cheap, and quick way for customers to enjoy a wide variety of products. However, due to the large number of online stores, a customer usually faces difficulties to review all available offers manually in order to find a favorite item. The Internet shopping optimization problem (ISOP) is a multiple-item multiple-shop...
Node cooperation approaches improve physical layer security in wireless networks without applying data encryption. Selecting the appropriate nodes to cooperate as relays or friendly jammers, to degrade eavesdropper's link, is a challenging problem which has attracted a lot of attention in recent years. Various approaches, based on conventional exhaustive search, have been suggested for optimal relay-jammer...
Orthogonal Frequency Division Multiplexing (OFDM) is a popular choice for high speed digital audio and video broadcast. Due to efficient spectral use and tremendous immunity towards inter-symbol interference (ISI), OFDM is used in downlink of 4-G Mobile systems. However high value of peak-to-average-power ratio (PAPR) is a major hindrance associated with OFDM systems and Partial Transmit Sequence...
The Resource-Constrained Project Scheduling Problem (RCPSP) is a classical well-known and NP-hard problem which includes the resource and precedence constraints that has been applied to many applications. This paper proposes the Radius Particle Swarm Optimization (RPSO) to solve the RCPSP. It extends the Particle Swarm Optimization (PSO) by regrouping the agent particles within the appropriate radius...
The concept of cancellation carriers (CCs) has been proposed in the literature for sidelobe suppression for orthogonal frequency division multiplexing (OFDM) systems. Subcarriers at the edges of the OFDM spectrum are used for sidelobe reduction while the remaining subcarriers are used for data transmission. Existing CCs techniques require performing complex optimization that should be applied for...
In this article we present an Elitism Levels Traverse Mechanism that we designed to find bounds on population-based Evolutionary Algorithms solving unimodal functions. We prove its efficiency theoretically and test it on OneMax function deriving bounds cμn log n-O(μn). This analysis can be generalized to any similar algorithm using variants of elitist selection and genetic operators that flip or swap...
Multiple-Input Multiple-Output (MIMO) antennas and Multi-Carrier Code Division Multiple Access (MC-CDMA) are very promising candidates for simultaneous utilize in 4G systems, since they attain robustness, high spectral efficiency, and high data rates in rich scattering environments. This paper proposes an efficient hybrid detection algorithm for a downlink MC-CDMA system based on Orthogonal Frequency...
Ever since the pioneering work of Y.C. Lim[1] on frequency response masking for the design of sharp FIR filters, lot of significant research have been carried out in this area. Among the various Signed Power of Two(SPT) forms, the Canonic Signed Digit(CSD) is a minimal representation, since it represents a given multiplier coefficient using minimum number of nonzero terms. This paper proposes the...
To solve two-dimensional (2D) rectangular packing problems, we introduce a new spatial method based on the discretization of the container into a grid of cells with predefined resolution. Before an item is added, grid cells are checked whether they can accommodate the item. If an appropriate empty cell cluster is found, the item is added and moved towards the bottom-left corner of the container. This...
Knapsack problem is regarded as a difficult NP problem in computer algorithms. According to the characteristics of knapsack problems, an algorithm (called KP-KEA) for solving knapsack problems utilizing knowledge evolution principle is proposed. In this algorithm, an initial knowledge base is formed at first. The next work is to inherit excellent knowledge individuals by inheritance operator, produce...
This paper discusses a model predictive control approach to hybrid systems with continuous and discrete inputs. The algorithm, which takes into account a model of a hybrid system, described as Hybrid Automaton. However, to avoid computational complexity and computation time, the nonlinear optimization problem is solved by evolutionary algorithms (EA) such as Genetic Algorithms (GA) and Particle Swarm...
In cluster computers, if the system load in each of computer is nearly equal, it indicates good resource utilization. It is well-known that load balancing is a key factor in developing parallel and distributed applications. Multiprocessor Scheduling is an NP-hard problem. The problem of scheduling a set of dependent or independent tasks in a distributed computing system is a well-studied area. In...
This paper presents a novel quantum-inspired algorithm(QGA) for the heavily constrained university scheduling problems(CUSP). The CUSP is a common problem for all institutions of higher education. It has been proved a NP problems. We propose a solving of CUSP based on the use of quantum-inspired algorithms. In the QGA, Q-bits based representation is employed by updating operator of quantum gate which...
Genetic Algorithms (GAs) are powerful general-purpose optimization search algorithms based upon the principles of evolution observed in nature. Mutation operator is one of the GA operators that used to produce new chromosomes or modify some features of it depending on some small probability value. The objective of this operator is to prevent falling of all solutions in population into a local optimum...
Routing and Wavelength Assignment (RWA) problem in Wavelength Division Multiplexed (WDM) optical networks assumes assigning the routes and wavelengths to be used to create the lightpaths on behalf of the connection requests. The RWA problem belongs to the class of combinatorial optimization problems. The optimal solution to the RWA problem is found to be NP-hard and thus suited to heuristic approaches...
This work presents an overlay multicast tree construction algorithm to support stable multimedia service over the Internet. While constructing a multicast tree, it takes into account not only the link delay, but also the peer stability. Since peers actually show dynamic and unstable behavior over peer-to-peer network, it is essential to consider the peer stability. Furthermore, the weighting factor...
The degree Δ-closest phylogenetic 2nd root problem (ΔCPR2) is an NP-hard problem concerning phylogenetic tree reconstruction from a graph representing the similarities of the species concerned. Here we present an approximation algorithm for this problem for any fixed Δ >; 3. When |V| >; 3Δ - 1, our algorithm yields an approximation ratio of max((Δ-2)/α, 2), where α >; 1 is a constant whose...
Both Genetic Algorithm (GA) and Linear Programming (LP) are effective optimization algorithms. LP is very efficient for optimizing linear problems. GA can attain very good solutions for integer non-linear problems, but it takes more time. To solve the very complex nested optimization problems, we propose a hybrid algorithm to combine the merits from both LP and GA algorithms in this paper. We use...
Task scheduling and task allocation, which are vital parts of mapping parallel programs to concurrent architectures, must take into account the interprocessor communication, whose overheads have emerged as the major performance limitation in parallel applications. Furthermore, its power consumption is an important research focus which must be addressed. Finding an optimal solution requires information...
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