• Korean Management Science Review
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• v.17 no.2
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• pp.115-124
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• 2000

Activity-Based Costing(ABC) is an accounting cost system which allocates the overhead cost to each cost object more accurately. ABC system achieves improved accuracy in estimating the cost of cost object by using multiple cost drivers to trace the cost of activities to the cost objects associated with the resources consumed by those activities. The selection and the aggregation of these cost driver candidates can pose difficult problems. This paper deals with these problems in mathematical programming approach. The first model is formulated as an integer programming model in cost driver selection and the second model is formulated as multi-objective goal programming model in reduction of cost drivers already selected.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.226-229
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• 2005

본 논문에서는 송전선로 도체의 경년열화(thermal deterioration)를 평가하기 위해 확률적 기법을 도입하였다. 선로의 경년열화를 나타내기 위해 선로의 장력(tensile strength) 감소를 계산하며 이는 해당 선로의 과거 전류 이력과 선로가 위치한 지역의 과거 기상데이터 및 부하량의 변화를 통해 산출한다 첫째로, 과거 데이터를 통해 확률분포를 구한 후 모든 데이터는 통계적으로 서로 간에 독립적이라는 가정 하에 Monte-Carlo Simulation을 수행하였다. 둘째로, 과거 데이터의 이력을 시간순서대로 추종하여 1시간 단위로 장력변화를 누적하는 순차적 계산(dynamic calculation)을 수행하였으며 그 결과를 MCS 기법과 비교하였다 주로 백분율로 표현하는 도체의 장력 감소분은 송전선로의 수명을 결정하는데 사용할 수 있는 중요한 지수이때, 계통계획에 있어서 유용한 기준으로 사용할 수 있을 것이다.

• Journal of the Korea Fashion and Costume Design Association
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• v.3 no.2
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• pp.137-160
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• 2001

A study on the structural change in the U.S. textile industry. The U.S. textile industry has undergone significant changes over the last fifty years, including a steady decline in the relative scale of domestic production, employment reduction, and increased competition from imported products. In order to weather a crisis, the responses of the U.S. textile industry have been made such as investment in technology, specalization in the textile and apparel industries. The textile and apparel industries have taken steps to increase labor productivity through automations to speed management to create and introduce new products and new methods, and have lowered indirect overhead costs. Regarding these response of the U.S. and other situation of world textile and apparel trade market, much of the sense of crisis that pervades korean textile and apparel industries has to do with the problem of adjusting corporate policy.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.338-341
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• 1999

PWM controlled line-side converters of modern ac traction locomotives inject harmonic currents into the feeding overhead line. This causes problem of electromagnetic interference. Passive and Active filters are usually provided for a reduction of the line harmonics. Active filters are more reasonable than passive filters in terms of weight and space of the filters. Successful control of active filters requires an accurate harmonic current reference. A technique to generate the harmonic current reference is proposed in this paper. The analysis is performed in frequency domain and its effectiveness is verified by simulation.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.431-432
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• 2008

We propose a DVS technique for multiprocessor systems considering the energy consumed when translating voltage. We schedule periodic applications on two identical processors throughout a three-stage process; firstly, the computation energy consumption is minimized then the number of voltage translations is minimized. Finally, the result is compared with the schedule with no voltage translation and the one with smaller energy consumption is chosen. Overall, 10.6% energy reduction was achieved.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.717-724
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• 2013

Industrial cranes are indispensable equipment in heavy industry. However, unwanted vibrations in cranes often cause accidents. Input shaping is widely accepted as a useful tool for removing residual vibration in cranes. A unity magnitude zero vibration (UMZV) input shaper is often used for cranes driven by on-off-type motors. However, although a UMZV input shaper minimizes residual vibration, the input shaper cannot prevent the crane from moving slightly further than expected from the original command. This paper describes an improved method of input shaping that can compensate for position inaccuracies, as well as remove the residual vibration of cranes. Experiments were performed to validate the proposed input-shaping method, illustrated through numerical simulations.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.397-400
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• 1999

As the result of enhancement of CAD, Design Automation and manufacturing technology, it's on the increasing complexity, integration ratio, data signals, and pin count to IC chips. This brings about difficulties of testing, and incresing test time. Now One of the most cost-consuming procedure as integration ratio increases is the testing step. In this paper, we propose a new method, “Efficient TP(test point) assignment algorithm” using “input grouping”, This is helpful method to reducing test length without losing fault coverage. Experimental results show that proposed method reduces test length remarkably and doesn't miss fault coverage, with low hardware overhead Increasing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3068-3078
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• 2015

Although the massive MIMO system supports a high throughput, it requires a lot of channel information for channel compensation. For the reduction of overhead, the massive MIMO system generally uses TDD as duplexing scheme. Therefore, the massive MIMO system is sensitive to rapidly changing fast fading in according to time. For the improvement of reduced SINR by fast fading, the adaptive power control is proposed. Unlike the conventional scheme, the proposed scheme considers mobility of device for adaptive power control. The simulation of the proposed scheme is performed with consideration for mobility of device. The result of the simulation shows that the proposed scheme improves SINR. Since SINR is decreased in according to the number of device in the network by unit of cell, each base station can accommodate more devices by the proposed scheme. Also, because the massive MIMO system with high SINR can use high order modulation scheme, it can support higher throughput.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.391-394
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• 2001

Occurring forest fire or burning bushes beneath overhead transmission lines have caused system disturbances in many countries. In this study, various tests in the simulated condition of power lines were conducted so as to investigate the reduction in insulation strength caused by combustion flame. The results of an experimental investigation into the flashover characteristics of air dielectric strength in the presence of oil flame are reported. It is demonstrated that flame can reduce by more than half, 80% in maximum, the breakdown voltage of a model line.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.110-113
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• 2017

현재 핸드폰 등 모바일 기계들의 사용의 증가에 따라 모바일 소비자는 매년 증가하고 있다. 현재뿐만이 아니라 미래까지 계속 증가 할 것으로 예상한다. 그래서 사용자의 지속적인 서비스 사용을 위해 사용 서비스를 고려한 단말 이동성대한 여러 가지 연구가 꾸준히 증가하고 있다. 이동성 지원을 위해 MIP, FMIP, PMIPv6등과 같은 여러 가지 솔루션들이 제안이 되었다. 이러한 연구들을 발전을 하는 형태의 연구들도 진행하고 있는 중이다. 하지만 이러한 솔루션들은 여러 가지 문제점을 가지고 있다. 본 논문은 여러 가지 문제점 중에 Controller 내부에서는 여러 가지 원인으로 오버헤드에 대해 초점을 두고 있다. 본 논문에서는 이러한 오버헤드를 줄이기 위해 Controller에 불필요한 flow들을 구별을 하는 기능을 하는 Controller application을 가진 기존과 다른 형태의 SDN 기반의 PMIPv6 구성을 제안한다.