• 한국통신학회논문지
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• 제31권3A호
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• pp.345-355
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• 2006

디지털 지상파 및 다중 표준(DVB-C, ISDB-T, DVB-H) 수신에 응용할 수 있는 RF 모듈을 개발하였다. 단일변환 방식을 적용하였고 광대역($45MHz{\sim}860MHz$) 방송 채별을 세 개(UHF, VHF_HIGH, VHF_LOW)의 대역으로 분할하여 영상신호 응답 및 위상잡음 특성, IF 평탄도와 같은 전기적 특성을 만족시킬 수 있었다. 또한 아날로그 방송과 디지털 방송이 함께 서비스되는 환경에서 아날로그 신호 및 디지털 신호의 인접채널 간섭 및 동일채널 간섭 특성과 같은 디지털 수신 성능 규격을 만족하도록 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.44.1-44
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• 2001

This paper discusses the interacting mobile robots for tele-operation system using the world wide web. In multi-agent and web-based teleoperation environment the problem of communication delay must be solved for the efficient and robust control of the system. The standard graphic user interface(GUI)is implemented using Java Programing language. The web browser is used to integrate the virtual environment and the standard GUI(Java applet) in a single user interface. Users can access a dedicated WWWserver and download the user interface. Reinforcement learning is applied to indirect control in order to autonomously operate without the need of human intervention. Java application has been developed to communicate and control multi robots using WWW. The effectiveness of our multi robots system is verified by simulation and experiments ...

• 대한전자공학회논문지
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• 제24권6호
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• pp.1074-1079
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• 1987

We present a fast, constructive algorithm for the automatic placement of standard cells, which consists of two steps. The first step is responsible for cell-row assignment of each cell, and converts the circuit connectivity into a multi-stage graph under to constraint that sum of the cell-widths in each stage of the multi-state graph does not exceed maximum cell-row width. Generatin of feed-through cells in the final layout was shown to be drastically reduced by this step. In the second step, the position of each cell within the row is determined one by one from left to right so that the cost function such as the local channel density is minimized. Our experimental result shows that this algorithm yields near optimal results in terms of the number of feed-through cells and the horizontal tracks, while running about 100 times faster than other iterative procedures such as pairwise interchange and generalized force directed relaxation method.

• 센서학회지
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• 제4권2호
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• pp.3-6
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• 1995

항온 유지 장치의 온도구배를 측정하기 위한 다중 접점을 갖는 K형 열전대를 제작하였다. 이 온도계를 사용하여 $800^{\circ}C$로 유지되고 있는 전기로의 온도구배를 측정하였으며, 교정용 기준기급의 S형 열전대와 비교한 결과 K형 열전대의 허용오차 범위 내에서 일치하였다. 더 정확한 온도구배 측정을 위해서는 귀금속 열전대를 사용하는 것이 바람직하다는 것을 제안하였다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2003년도 정기총회 및 추계학술대회
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• pp.95-100
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• 2003

The purpose of this study is to evaluate the noise environment of one-room type multi-family housing around the campus. The field measurements on equivalent noise level of indoor and outdoor were carried out in 6 subject house units during the 26th${\sim}$28th of November 2002. The results are as follows. 1) Outdoor noise levels of 6 subject buildings were distributed 52.8${\sim}$65.3dB(A) and were inappropriate to the standard for environmental noise, 55dB(A). 2) Indoor noise level of 6 subject house units were measured 27.5${\sim}$63.5dB(A). These values were higher than the indoor noise standard (40dB(A)) except subject house D(average 37.6dB(A)). 3) It was found that the differences of indoor noise levels between subject house units were caused by resident's living factor, characteristics of window, and existence of balcony.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.350-356
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• 2005

A method of dynamic analysis of mechanical systems considering probabilistic properties is proposed in this paper. Probabilistic properties that result from manufacturing tolerances can be represented by means and standard deviations (or variances). The probabilistic characteristics of dynamic responses of constrained multi-body systems are obtained by two ways : the proposed analytical approach and the Monte Carlo simulation. The formerpaper, necessitates sensitivity information to calculate the standard deviations. In this a direct differentiation method is employed to find the sensitivities of constrained multi-body systems. To verify the accuracy of the proposed method, numerical examples are solved and the results obtained by using the proposed method are compared to those obtained by Monte Carlo simulation.

• 경영과학
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• 제24권2호
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• pp.73-80
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• 2007

Robust Design(RD) is a cost-effective methodology to determine the optimal settings of control factors that make a product performance insensitive to the influence of noise factors. To better facilitate the robust design optimization, a dual response surface approach, which models both the process mean and standard deviation as separate response surfaces, has been successfully accepted by researchers and practitioners. However, the construction of response surface approximations has been limited to problems with only a few variables, mainly due to an excessive number of experimental runs necessary to fit sufficiently accurate models. In this regard, an innovative response surface approach has been proposed to investigate robust design optimization problems with larger number of variables. Response surfaces for process mean and standard deviation are partitioned and estimated based on the multi-level approximation method, which may reduce the number of experimental runs necessary for fitting response surface models to a great extent. The applicability and usefulness of proposed approach have been demonstrated through an illustrative example.

• Smart Structures and Systems
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• 제21권2호
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• pp.235-248
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• 2018

An efficient method utilizing the multi-stage improved differential evolution algorithm (MSIDEA) as an optimization solver is presented here to detect the multiple-damage of structural systems. Natural frequency changes of a structure are considered as a criterion for damage occurrence. The structural damage detection problem is first transmuted into a standard optimization problem dealing with continuous variables, and then the MSIDEA is utilized to solve the optimization problem for finding the site and severity of structural damage. In order to assess the performance of the proposed method for damage identification, an experimental study and two numerical examples with considering measurement noise are considered. All the results demonstrate the effectiveness of the proposed method for accurately determining the site and severity of multiple-damage. Also, the performance of the MSIDEA for damage detection compared to the standard differential evolution algorithm (DEA) is confirmed by test examples.

• 제어로봇시스템학회논문지
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• 제11권4호
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• pp.297-303
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• 2005

In this paper, I developed an intelligent multi agents based softPLC(IMPLC). In IMPLC, the standard IEC 1131-3 PLC languages(LD, SFC, FBD, ST) programmed by a user are converted to IL, which is one of intermediate codes, in order to make them interactions. And then the IL is converted to the standard C code regarding some extension and transplanting, which can be used in a commercial editor such as visual C++. In IMPLC, the logical errors and syntax errors occurred by users are detected, so that the optimal PC control based softPLC can be possible. IMPLC provide easy programming platform to such beginner as well as professionals. The study of code conversion is firstly tried in the world as well as KOREA. I applied IMPLC to 3 steps conveyer belt system. The simulation results say that the debugging steps by IMPLC using multi agents are decreased than the conventional softPLC's.

• 한국멀티미디어학회논문지
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• 제25권1호
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• pp.61-71
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• 2022

When communication such as light, radio wave, or magnetic field is used underwater, the communication distance is very short, so sound waves are mainly used. However, by combining the strengths of each medium and communicating, stable communication may be possible. Underwater multi-media communication requires a protocol stack that supports it, which is very complex. To this end, this paper proposes a standard protocol stack and modeling technique to enable easy protocol stack modeling for the purpose. In fact, in this paper, a random model was created and analyzed through the proposal of modeling elements and similarity measurement methods, and as a result, it was analyzed that it was very helpful in creating a new model based on a standard model.