• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.81-90
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• 2013

A study on the flow-structure characteristics of marine 3/2WAY pneumatic valve is essential for optimizing the performance of ship engines. It is important that the valve has desirable safety factor and reduced weight from safety and economic point of view. In this paper, flow-structure characteristics of pneumatic valve is obtained by being optimized based on the proper design criteria. The air with the pressure of 30 bar is the working fluid which is made to fill in the tack in short time. This time is defined as the filling time. On optimum design by considering the flow-structure characteristics, the approach is based on (1) the mathematical formulation of design decisions using the compromise decision-making method, and (2) the approximation technique of response surfaces. The methodology is demonstrated as the multi-objective optimization tool to improve the performance of marine 3/2WAY pneumatic valve.

• Journal of Intelligence and Information Systems
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• v.12 no.2
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• pp.125-144
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• 2006

The development of mobile applications is fast in recent years. However, nearly all applications are for messaging, financial, locating services based on simple interactions with mobile users because of the limited screen size, narrow network bandwidth, and low computing power. Processing an algorithm for supporting a group decision process on mobile devices becomes impossible. In this paper, we introduce the mobile-oriented simple interactive procedure for support a group decision making process. The interactive procedure is developed for multiple objective linear programming problems to help the group select a compromising solution in the mobile Internet environment. Our procedure lessens the burden of group decision makers, which is one of necessary conditions of the mobile environment. Only the partial weak order preferences of variables and objectives from group decision makers are enough for searching the best compromising solution. The methodology is designed to avoid any assumption about the shape or existence of the decision makers' utility function. For the purpose of the experimental study of the procedure, we developed a group decision support system in the mobile Internet environment, MOBIGSS and applied to an allocation problem of investor assets.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.493-499
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• 2003

현재 공시지가를 산정하는 과정에서 비교 표준지를 선정하는 작업은 지적 담당공무원의 수작업에 의하여 이루어지고 있다. 한정된 시간에 많은 개별필지의 비교표준지선정 작업으로 인하여, 객관적이고 합리적인 비교표준지를 선정하는 것에 어려움이 있다. 또한 현재 NGIS(국가지리정보체계)나 UIS(도시정보체계)등에 의한 국가적인 지형정보체계 구축사업이 급속도로 진전되고 있다. 이에 따라 토지의 가치평가의 한 분야인 개별토지의 지가산정작업도 최신의 자동화된 기법을 적용할 필요성이 증대되고 있다. 따라서, 본 연구에서는 비교표준지를 선정하는 작업을 자동화함으로써 수작업에 의한 주관적인 요소를 배제하고, 객관적이고 정확하게 비교표준지를 선정하는 방법을 알아보았다. 아울러 이러한 자동화 기법을 사용함에 있어서 공간의사결정모델을 이용하여 비교 표준지와 개별 필지간의 토지특성을 충분히 고려하여 비교표준지를 선정함으로써 정확도를 높이는 방안을 모색하였다. 본 연구에서는 다양한 의사결정기법 중에서 계층분석과정(AHP)기법, Concordance 기법 그리고 Ideal Point 기법을 사용하여 비교표준지를 선정하였다. 3가지 방법을 통하여 나온 결과를 현재의 비교표준지와 비교하여본 결과, 계층분석과정기법이 가장 현실성이 있는 대안으로 선정 되었다. 본 연구의 결과와 현재 사용중인 비교표준지를 절충하여 좀더 현실적인 비교표준지 선정이 이루어질 것으로 기대한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.217-225
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• 2009

Tone injection scheme has been known as one of peak to average power ratio (PAPR) reduction methods deployable to multi-carrier system like orthogonal frequency division multiplexing (OFDM). The basic idea in tone injection scheme is to enforce the constellation size larger so that each of original constellation points is mapped into the preassigned distinct locations. According to the tone injection scheme, it increases symbol power highly induced inherently by expanding constellation to get optimal PAPR reduction. In the other hand, to get optimal power increase, the PAPR would be reduced insufficiently with limited tone injection signal. To withstand these problems, this paper consider the reduction of the PAPR and power increase problem simultaneously, Toward this, the tone injection scheme accomplished by employing the weighted sum genetic algorithm which has been utilized to solve multi-objective optimization problem (MOOP). The simulation results verifies that the proposed scheme can control the effective PAPR performance and alleviation of power increase flexibly by the weight value at the expense of relatively low complexity.