• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.918-919
• /
• 2011

본 논문에서는 특수차량용 발전기 시스템에 적용되는 3.5kW급 매입형 영구자석 동기발전기의 설계 및 특성해석에 대해 나타내었다. 본 연구에서는 DC전원의 전압을 280[V], 발전기 측에서 발생하는 선간전압을 293.2[V]로 설정하여 설계하였다. 정격속도 2,000[rpm]에서 정상 구동하는 발전기를 목표로2차원 유한요소해석을 통하여 속도별 역기전력과 정격에서의 전압, 전류, 출력에 대해 실험값과 비교 검증하였고, 약계자 제어를 통해 각 속도 영역에서 일정전압이 유기됨을 실험을 통해 검증하였다.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.33 no.4
• /
• pp.45-57
• /
• 2010

This paper considers a 2-stage assembly flowshop scheduling problem where each job is completed by assembling multiple components. The problem has the objective measure of minimizing total completion time. The problem is shown to be NP-complete in the strong sense. Thus, we derive some solution properties and propose three heuristic algorithms. Also, a mixed-integer programming model is developed and used to generate a lower bound for evaluating the performance of proposed heuristics. Numerical experiments demonstrate that the proposed heuristics are superior over those of previous research.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.31 no.4
• /
• pp.35-47
• /
• 2006

This paper considers an integrated scheduling problem for consecutive production and delivery stages in a two-stage supply chain. The Production is performed on a single facility and then the finished products are delivered to the customer by capacitated multiple vehicles. The objective of this paper is to obtain job sequencing and delivery batching minimizing the total cost of the associated WIP inventory, finished product inventory and delivery. The inventory cost is characterized by the sum of weighted flowtime. The delivery cost is proportional to the required number of delivery batches. Some polynomial-solvable cases are derived. For the general case, two efficient heuristic algorithms are suggested, and then the heuristics are tested through some numerical experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.9
• /
• pp.982-989
• /
• 2008

There is a noticeable hum from the inverter board of LCD TV when in operation. In this study, we investigate the source and the characteristics of this noise for the inverter board of LCD TV using measurement of vibration and noise. Modal analysis of vibration and noise is visualized for identification of noise sources and transmission vibration. The main source of noise was the transformer of the LCD TV inverter. A noise reduction was achieved by damping the structural elements.

• Proceedings of the KIEE Conference
• /
• 2004.10a
• /
• pp.46-48
• /
• 2004

Recently, the study of sensorless drive of IPMSM is coming to be active. In sensorless drive, because the wrong estimation of the initial rotor position brings about the decrease of the starting torque, or a temporary reverse revolution, it is important to know the exact importation of the initial rotor position. In this paper, the initial rotor position estimation method is based on the current peak measured by applying the pulsewise voltage and the current peak is changed according to the rotor position owing to the saliency of the rotor. The effectiveness of the proposed algorithm is verified by the experimental results.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.33 no.2
• /
• pp.87-101
• /
• 2008

This paper considers an order scheduling model to minimize the total weighted tardiness of orders. Each order requires different types of products. Each type of product is manufactured on its dedicated machine specified in advance. The completion time of each order is represented by the time when all the products belonging to the order are completed. The objective of this paper is to find the optimal production schedule minimizing the total weighted tardiness of a finite number of orders. In the problem analysis, we first derive a powerful solution property to determine the sequence of two consecutive orders. Moreover, two lower bounds of objective are derived and tested along with the derived property within a branch-and-bound scheme. Two efficient heuristic algorithms are also developed. The overall performances of the proposed property, branch-and-bound and heuristic algorithms are evaluated through various numerical experiments.

• IE interfaces
• /
• v.12 no.3
• /
• pp.401-405
• /
• 1999

We present a simulation model to generate the spatial distribution of mobiles in cellular communication network. Three types of spatial distributions are considered; biased, random, and ratio-based distributions. This study also points out and corrects the critical errors performed by Das and Morgera(1997) in getting random location of mobiles. By applying a simple path loss model, the effects of our correction on the signal-to-interference(SIR) ratio are discussed. The numerical results indicate that the variation of SIR in the Das's biased distribution is larger than that of other distributions. As compared with the random distribution, the average SIR error of the biased distribution is 91.1%.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.4
• /
• pp.112-120
• /
• 2001

In this paper, the development of a new group controller for high-speed elevator is carried out utilizing the approach of an adaptive dual fuzzy logic. Some goals of control are the minimization of waiting time, mean-waiting time and long-waiting time in a high building, when a new hall call is generated, adaptive dual fuzzy controller evaluate traffic pattern and change appropriately the membership function of a fuzzy rule base. Controls for co-operation among elevators in a group control algorithm arte essential, and the most critical control function in the group controller is an effective and proper hall call assignment of elevators. The group elevator system utilizing adaptive dual fuzzy control reveals a great deal of improvement on its performance.

• 대한예방의학회:학술대회논문집
• /
• 2002.10a
• /
• pp.385-385
• /
• 2002

• 대한예방의학회:학술대회논문집
• /
• 2002.10a
• /
• pp.175-176
• /
• 2002