• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3771-3788
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• 2015

This paper studies the distributed energy efficient resource management in the Internet of Things (IoT). Wireless communication networks support the IoT without limitation of distance and location, which significantly impels its development. We study the communication channel and energy management in the wireless communication network supported IoT to improve the ability of connection, communication, share and collaboration, by using the game theory and distributed learning algorithm. First, we formulate an energy efficient neighbor collaborative game model and prove that the proposed game is an exact potential game. Second, we design a distributed energy efficient channel selection learning algorithm to obtain the global optimum in a distributed manner. We prove that the proposed algorithm will asymptotically converge to the global optimum with geometric speed. Finally, we make the simulations to verify the theoretic analysis and the performance of proposed algorithm.

• 대한기계학회논문집A
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• 제28권10호
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• pp.1558-1565
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• 2004

It is important to determine supporting locations for structural stability when a structure is loaded with non-uniform load or supporting locations as well as the number of the supporting structures are restricted by the problem of space. Moreover, the supporting location optimization of complex structure in real world is frequently faced with discontinuous design space. Therefore, the traditional optimization methods based on derivative are not suitable Whereas, Genetic Algorithm (CA) based on stochastic search technique is a very robust and general method. The KSTAR in-vessel control coil installed in vacuum vessel is loaded with non- uniform electro-magnetic load and supporting locations are restricted by the problem of space. This paper shows the supporting location optimization for structural stability of the in-vessel control coil. Optimization has been performed by means of a developed program. It consists of a Finite Element Analysis interfaced with a Genetic Algorithm. In addition, this paper presents an algorithm to find an optimum solution in discontinuous space using continuous design variables.

• 한국도로학회논문집
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• 제16권3호
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• pp.51-57
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• 2014

PURPOSES : This study is to suggest tunnel length to spray curing compound, based on the field tests. METHODS : At first field test, length from the entrance of tunnel to wet wall was checked by visual survey. The second and third test, various sensors were installed in concrete or in tunnel, such as RH sensor, temperature sensor, portable weather station and etc.. And also, test for bleeding and retaining water of concrete were conducted to evaluate environmental effect on concrete pavement. RESULTS : The result of the field experiment for tunnel length to spray curing compound indicates that length changes depending on tunnel length, season, and location. Environmental condition of a short tunnel was not much different between location near entrance and at center of tunnel. However, in case of a medium and long tunnel, effect of outside environmental condition decreased, when location moved into tunnel center of it. CONCLUSIONS : From the testing results, it can be proposed that optimum tunnel length to spray curing compound is 60m for a medium and long tunnel, and whole length for a short tunnel.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.8-14
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• 2003

광센서 조광제어시스템은 실내로 유입되는 주광량에 따라 자동으로 광속량을 조절하여 설정조도를 유지시켜주는 에너지절약 시스템이다. 이 시스템의 성공여부를 결정하는 여러 요인들 중, 광센서의 측광값이 작업면 조도를 얼마나 정확히 나타내는가가 중요한 포인트가 된다. 그래서 본 연구에서는 실험을 통해 광센서의 여러 측광방향 형태를 결정하고, 각 측광방향별 광센서의 반응신호를 측정하였다. 그리고 광센서의 적절한 위치를 찾기 위해 실제공간에서 서로 다른 위치에 광센서를 설치하여, 작업면 조도와 광센서 반응신호의 관계를 측정하고 분석하였다. 분석된 결과를 토대로 광센서의 적절한 위치와 측광방향성을 제시하였다.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.120-129
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• 2012

As the recent advancement of automobile industry, there has been a great interest in the thermal comfort of the passengers inside the cabin of an automobile. Thermal comfort is affected by temperature, velocities, and mean radiation temperature of air, thermal resistance of clothes and physical active level of human. The present study performed computational analysis to select the location of air-conditioning vent that improves thermal comfort inside the cabin. In order to do this, we considered various air vent positions, and thermal flow analysis of each case is performed using CFD for the cabin with four passengers. The thermal comfort is evaluated using the computational results and the optimum location of air vent is suggested.

• 한국정밀공학회지
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• 제15권3호
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• pp.31-37
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• 1998

The structure of satellite consists of six parts which are control system, power system, thermal control system, remote measurement command system, propellant system and thrust system. In these parts, propellant system consists of propellant tank and thrust device. What we want to perform is optimum design to minimize the weight of propellant tank. In order to design optimal propellant tank, several parameters should be adopted from the tank geometry like the relative location of the lug and variation of the wall thickness. The analysis was executed by finite element analysis for finding optimal design parameters. The structure was divided into three parts consisting of the initial thickness zone, the transitional Bone, and the weak zone, whose effects on the pressure vessel strength was investigated. Finally the optimal lug location and the three zone thickness were obtained and the weight was compared with the uniform thickness vessel.

• Steel and Composite Structures
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• 제38권6호
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• pp.671-690
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• 2021

Seismic responses of RC core wall with two outriggers are investigated in this study. In the models analyzed here, one of the outriggers is fixed at the top of the building and the second is placed at different levels along the height of the system. Each of the systems resulting from the placement of the outrigger at different locations is designed according to the prescriptive codes. The location of the outrigger changes along the height. Linear design of all the structures is accomplished by using prescriptive codes. Buckling restrained braces (BRBs) are used in the outriggers and forward directivity near fault and far fault earthquake record sets are used at maximum considered earthquake (MCE) level. Results from nonlinear time history analysis demonstrate that BRB outriggers can change the seismic responses like force distribution and deformation demand of the RC core-walls over the height and lead to the new plastic hinge arrangement over the core-wall height. Plasticity extension in the RC core wall occurs at the base as well as adjacent to the outrigger levels. Considering the maximum inter-story drift ratio (IDR) demand as an engineering parameter, the best location for the second outrigger is at 0.75H, in which the maximum IDR at the region upper the second outrigger level is approximately equal to the corresponding value in the lower region.

• 한국구조물진단유지관리공학회 논문집
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• 제12권5호
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• pp.179-189
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• 2008

본 연구는 능동텐던을 이용 지진을 받는 구조물의 최적 능동제어 방법에 관한 수치해법 적용 및 프로그램 개발에 목적이 있다. 능동텐던 시스템에 의한 제어이론을 적용하기 위해서 Ricatti 폐회로 알고리즘을 이용하였으며, 시간지연 문제를 고려하였다. 최적제어의 정식화를 위해서 SUMT기법의 최적화에 의해 성능지수를 최소로 하는 최적 가중치행렬을 추정토록 하였다. 구조물에서의 능동텐던의 최적 위치 선정을 위해서 가제어지수에 의한 방법을 소개하였다. 수치 예를 통해, 제어기의 최적 위치선정을 고려한 능동최적제어가 지진하중을 받는 구조물의 성능제어에 우수한 효과를 나타내는 것으로 평가되었다.

• 에너지공학
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• 제13권1호
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• pp.34-39
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• 2004

본 논문에서는 압축공기를 작동매체로 한 저압용 보텍스튜브에 대한 에너지 분리과정을 상세히 연구하였다 먼저 보텍스튜브에서 에너지 분리되어 나오는 온공기와 냉공기의 온도변화에 대하여 실험하였고, 보텍스튜브의 안쪽표면의 최대벽면온도 변화와 보텍스튜브 내의 온도분포를 통하여 보텍스튜브 내 유동장에서의 정체점의 위치에 대한 유용한 정보를 얻게 되었다. 이를 바탕으로 보텍스튜브의 노즐면적비와, 오리피스의 크기에 따른 에너지분리 과정 등을 실험을 통하여 알아보았다. 이러한 기하학적 형상의 변화실험을 통하여 저압용？대형 보텍스튜브의 에너지 분리과정이 고압형\ulcorner소형 보텍스튜브 보다 에너지 분리효과가 증대됨으로 인하여 최적의 노즐면적비와 오리피스지름비가 차이가 있음을 알 수 있었다.

• 대한전기학회논문지:전력기술부문A
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• 제54권5호
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• pp.234-241
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• 2005

The performance of passive conductor loop (hereinafter 'loop') method which is used to mitigate the magnetic field around overhead power transmission line is dependent on its configuration and installed location, which are affected by installation conditions of the loops such as objective areas and levels of magnetic field mitigation. Thus, because the design problem of loops is difficult and cumbersome by variety of their configuration and complexity of magnetic coupling mechanism, it is need to be formulated as a computer-based optimum problem to determine the most effective and reasonable loop model satisfying the installation conditions. In this paper, the optimum locations of the multi-wired multiple loops including series reactance compensations are searched by using the genetic algorithm (GA) to mitigate effectively the magnetic fields of relatively near points or far points from transmission line at Am height, and the magnetic fields mitigation characteristics of each loop are analyzed in the view of magnitude, direction and phase of cancellation fields by polarized vector concept to identify their adequacy and rationality for the installation objectives.