• Smart Structures and Systems
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• 제15권1호
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• pp.191-207
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• 2015

Proper placement of sensors plays a key role in construction and implementation of an effective structural health monitoring (SHM) system. This paper proposes a novel methodology called the distributed monkey algorithm (DMA) for the optimum design of SHM system sensor arrays. Different from the existing algorithms, the dual-structure coding method is adopted for the representation of design variables and the single large population is partitioned into subsets and each subpopulation searches the space in different directions separately, leading to quicker convergence and higher searching capability. After the personal areas of all subpopulations have been finished, the initial optimal solutions in every subpopulation are extracted and reordered into a new subpopulation, and the harmony search algorithm (HSA) is incorporated to find the final optimal solution. A computational case of a high-rise building has been implemented to demonstrate the effectiveness of the proposed method. Investigations have clearly suggested that the proposed DMA is simple in concept, few in parameters, easy in implementation, and could generate sensor configurations superior to other conventional algorithms both in terms of generating optimal solutions as well as faster convergence.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.466-473
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• 2000

Optimality Criteria algorithm based on the derivation of reciprocal approximations has been applied to structural optimization of large-scale structures. However, required computational cost for the serial analysis algorithm of large-scale structures consisting of a large number of degrees of freedom and members is too high to be adopted in the solution process of O.C. algorithm Thus, parallel version of O.C. algorithm on the network of personal computers is presented in this Paper. Parallelism in O.C. algorithm may be classified into two regions such as analysis and optimizer part As the first step of development of parallel algorithm, parallel structural analysis algorithm is developed and used in O.C. algorithm The algorithm is applied to optimal design of a 54-story plane frame structure

• 전기학회논문지
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• 제56권3호
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• pp.451-456
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• 2007

This paper presents a problem that reconfigure distribution power system using branch exchange method. Optimal reconfiguration problem calculates line loss, voltage condition about system states of all situations that become different according to line On/off status, and search for optimum composition of these. However, result is difficult to be calculated fast. Because radiated operation condition of system is satisfied using many connection and sectionalize switches in the distribution power system. Therefore, in this paper, optimization method for reducing system total loss and satisfying operating condition of radial and constraints condition of voltage is proposed using the fastest branch exchange. And optimal solution at branch exchange algorithm can be wrong estimated to local optimal solution according to initial operating state. Considering this particular, an initial operating point algorithm is added and this paper showed that optimal solution arrives at global optimal solution.

• 제어로봇시스템학회논문지
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• 제21권1호
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• pp.28-33
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• 2015

In this paper, we propose a near optimal controller design method for permanent magnet synchronous generators (PMSGs) of MW-class direct-driven wind turbine systems based on SDRE (State Dependent Riccati Equation) approach. Using the solution matrix of an SDRE, we parameterize the optimal controller gain. We present a simple algorithm to compute the near optimal controller gain. The proposed optimal controller can enable PMSGs to precisely track the reference speed determined by the MPPT algorithm. Finally, numerical simulation results are given to verify the effectiveness of the proposed optimal controller.

• Journal of Information Processing Systems
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• 제16권4호
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• pp.959-974
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• 2020

High efficiency video coding (HEVC) employs quadtree coding tree unit (CTU) structure to improve its coding efficiency, but at the same time, it also requires a very high computational complexity due to its exhaustive search processes for an optimal coding unit (CU) partition. With the aim of solving the problem, a fast CU size decision optimal algorithm based on neighborhood prediction is presented for HEVC in this paper. The contribution of this paper lies in the fact that we successfully use the partition information of neighborhood CUs in different depth to quickly determine the optimal partition mode for the current CU by neighborhood prediction technology, which can save much computational complexity for HEVC with negligible RD-rate (rate-distortion rate) performance loss. Specifically, in our scheme, we use the partition information of left, up, and left-up CUs to quickly predict the optimal partition mode for the current CU by neighborhood prediction technology, as a result, our proposed algorithm can effectively solve the problem above by reducing many unnecessary prediction and partition operations for HEVC. The simulation results show that our proposed fast CU size decision algorithm based on neighborhood prediction in this paper can reduce about 19.0% coding time, and only increase 0.102% BD-rate (Bjontegaard delta rate) compared with the standard reference software of HM16.1, thus improving the coding performance of HEVC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.587-590
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• 1988

In the case of VLSI computer system control unit design using PLA, optimal state code assignment algorithm to minimize the PLA area is proposed. An optimal state code assignment algorithm which considers output state and logic minimization simultaneously is proposed, and by means of this, algorithm product term is minimized. Also, by means of this algorithm running time and memory capacitance is decreased as against heuristic state code assignment algorithm which uses matrix calculation and considers the constraint relation only. This algorithm is implemented on VAX 11/750 (UNIX4.3BSD). Through the various test example applied proposed algorithm, the efficiency of this algorithm is shown.

• 한국CDE학회논문집
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• 제6권3호
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• pp.174-183
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• 2001

This study proposes an improved genetic algorithm (GA) to derive solutions for facility layout problems having inner walls and passages. The proposed algorithm models the layout of facilities on a flour-segmented chromosome. Improved solutions are produced by employing genetic operations known as selection, crossover, inversion, mutation, and refinement of these genes for successive generations. All relationships between the facilities and passages are represented as an adjacency graph. The shortest path and distance between two facilities are calculated using Dijkstra's algorithm of graph theory. Comparative testing shows that the proposed algorithm performs better than other existing algorithm for the optimal facility layout design. Finally, the proposed algorithm is applied to ship compartment layout problems with the computational results compared to an actual ship compartment layout.

• 한국산업융합학회 논문집
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• 제4권1호
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• pp.41-49
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• 2001

This study developed signal optimization algorithm by analyzing vehicle arrival patterns. The major principle of signal optimization is dissipate all queueing vehicle in 1cycle and assign delay time uniformly for all approaches. For this, this study used optimal green time and surplus green time. Optimal green time calculated by estimated traffic volume from vehicle arrival model. Surplus green time defined as the gap of optimal green time and queue dissipated time. And alternative cycle has minimum surplus green time was selected as the optimal cycle. Finally, total delay and average delay per vehicle can be calculated by using queueing theory.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.246-248
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• 2004

In this paper, we propose an optimal power control algorithm for CDMA cellular systems. The proposed power control algorithm is based on linear quadratic control theory. As the cellular system includes the changeability of system environment or various noise, Kalman filter is adapted to estimate the time-varying interference. This is the well-known linear quadratic Gaussian (LQG) theory. Through this algorithm, power transmission of each mobile with optimal one is more realistic. Simulation results show a fast convergence rate to optimal power value, and a rapid decreasing outage probability.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.122-130
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• 2001

In this paper, an operational algorithm for a 2-shaft parallel hybrid electric vehicle is suggested for the minimization of operation cost. The operation cost is obtained as a summation of the engine fuel cost and the motor electricity cost. The electrical cost function is estimated in case of motoring, and generating when the recuperation is carried out during the braking. In addition, weight function is introduced in order to maintain the battery state of charge. Based on the operation algorithm, the optimal engine operation point that minimizes the operation cost is obtained with respect to the required vehicle power for every state of charge of battery. The optimal operation point provides the optimal power distribution of the engine and the motor for a required vehicle power Simulation was performed and the fuel economy of the hybrid vehicle was compared to that of the conventional vehicle. Simulation results showed that hybrid vehicle's fuel economy can be improved as much as 45∼48% compared to the conventional vehicle's.