• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.495-497
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• 1994

Given the constraint of the AC input power factor and the DC-link voltage and current ripple in voltage source inverter, minimizing the size and cost of the DC-link fitter components is very important. This paper presents a procedure for the selection of DC-link filler element values in a three-phase PWM voltage source inverter-fed induction motor drive system, which can not only satisfy the requirements for the system performance but also minimize the filter size.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.1
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• pp.17-26
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• 2000

This paper presents an integrated order scheduling method with the improved DRP concept for multi-echelon distribution system that has the constraint of limited production capacity of producers. The proposed method reflects the dynamic characteristics of inventory level changes in the regional and central distribution center. The simulation is done with two models : the traditional DRP method and the proposed method presented in this paper. From the results, the latter is more efficient than the former in cost, customer's service level as well as balanced production load on each producer.

• Journal of Navigation and Port Research
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• v.32 no.7
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• pp.553-559
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• 2008

The lorry based transportation system in korea has many problems such as high domestic logistic cost, environment pollution and road damage etc. Hereupon, the necessity of improvement for national logistics system has been proposed continuously. Therefore we carried out this research through AHP(Analytic Hierarchy Process) to measure relative importance between effect factors and constraint factors and examined the possibility of Modal Shift from lorry transportation to coastal transportation. As the results of this research, the relative priority on modal shift policy enforcement (0.556) is higher than that of maintenance of the present transportation system(0.444).

• Journal of Communications and Networks
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• v.18 no.5
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• pp.762-772
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• 2016

This paper studies the problem of precoding and post-coding design for multicell multiuser downlink transmissions in the absence of perfect channel state information (CSI). Using statistical information of imperfect CSI, an iterative multiuser multicell transceiver design is formulated by minimizing the mean squared error (MSE) cost function of signal and leakage interference under per-base station power constraint (PBPC). The convergence of the iterative precoding and postcoding algorithm is verified by analytical and empirical results. The proposed precoding and postcoding algorithm offers a low computational complexity and robustness against CSI imperfection.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.247-249
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• 2005

국내 계통을 운영함에 있어서 융통선로의 송전제약 때문에 수도권 지역의 고단가 발전기가 지방의 저단가 발전기를 대신하여 운영해야 하는 경우가 빈번하게 일어나고 있으며, 이에 따른 송전제약 비용의 발생이 크게 증가하고 있다. 본 논문에서는 송전계통제약 운전량 산정 기준 및 제약비용 부담주체 타당성 및 산정기법 개발 과제 진행 중 연구 검토한 송전제약 비용에 대하여 기술하고자 한다.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.1
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• pp.105-111
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• 2002

When transporting multiple items by trucks of various size, one needs to assign a group of items to each truck so as to minimize the total cost, while meeting the weight and volume constraint of each truck. In this paper, we formulate the problem as an integer programming problem and propose four heuristic algorithms for the problem. Computer simulation is used to evaluate the average performance of the four heuristic algorithms for the consolidated transportation problem.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.1
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• pp.66-70
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• 1997

In this paper a new learning algorithm for curvature smoothing and improved generalization for multi-layer neural networks is proposed. To enhance the generalization ability a constraint term of hidden neuron activations is added to the conventional output error, which gives the curvature smoothing characteristics to multi-layer neural networks. When the total cost consisted of the output error and hidden error is minimized by gradient-descent methods, the additional descent term gives not only the Hebbian learning but also the synaptic weight decay. Therefore it incorporates error back-propagation, Hebbian, and weight decay, and additional computational requirements to the standard error back-propagation is negligible. From the computer simulation of the time series prediction with Santafe competition data it is shown that the proposed learning algorithm gives much better generalization performance.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.19-26
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• 2010

This study was conducted to find out the reasonable optimum design method of agricultural reinforced concrete structures. Selected design variables are the dimension of concrete section, reinforced steel area, and objective function is formulated by cost function. To test the reliability, efficiency, possibility of application and reasonability of optimum design method, both continuous optimization method and mixed-discrete optimization method were applied to the design of reinforced concrete superstructure of aqueduct and application results were discussed. It is proved that mixed-discrete optimization method is more reliable, efficient and reasonable than continuous optimization method for the optimum design of reinforced concrete agricultural structures.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.67-72
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• 2010

In this study, performance analysis and design optimization is carried out for a multi-rate spring brake system, which is used in a cable ride to stop the arriving passengers in safe and comfortable manner. Mathematical model for the spring is developed toward the objective of minimizing the impact at the arrival while satisfying the constraint of limited distance at the stop. Matlab code is utilized to examine parameters affecting the performance of the brake system. The results are validated by a commercial software RecurDyn. Kriging meta model is used to reduce the computational cost of the analysis. Optimization is conducted by RecurDyn, from which the design parameters are determined that minimizes the impact at the stop.

• Advances in robotics research
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• v.1 no.2
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• pp.171-183
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• 2014

Distributed planning and decision making can be beneficial from the robustness, adaptability and fault tolerance in multi-robot systems. Distributed mechanisms have not been employed in three dimensional transportation systems namely aerial and underwater environments. This paper presents a distributed cooperation mechanism on multi robot transportation problem in three dimensional environments. The cooperation mechanism is based on artificial capital market, a newly introduced market based negotiation protocol. In the proposed mechanism contributing in transportation task is defined as asset. Each robot is considered as an investor who decides if he is going to invest on some assets. The decision is made based on environmental constraint including fuel limitation and distances those are modeled as capital and cost. Simulations show effectiveness of the algorithm in terms of robustness, speed and adaptability.