• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.430.1-430.1
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• 2003

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1621-1623
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• 1997

Use of teaching pendant is the most widespread and economical way to teach desired motion to robots. It is also very primitive,time consuming and ineffective way of teaching which has not changed since the early days of robot. In order to reduce the teaching effor, a new efficient form of teaching is needed. Also, the recent robotics research trend into service robots such as home robot, nurse robot and medical robot calls for a new teaching method which is both easy and inexpensive. In this paper, the design and operation principle of a low cost force/moment sensor is presented. The proposed sensor architecture is so simple and inexpensive that it opens the prospect for a new paradigm of robot teaching which is easy and efficinet. Other prospective areas of application are tele-manipulation of robots wher it can be used in master arm, and virtual environment where it can be used as an user input device.

• Transactions of Materials Processing
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• v.4 no.1
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• pp.92-104
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• 1995

It often happens some elements are so largely distorted during a large-deformation finite element analysis that further calculation becomes impossible or the approximation error increases rapidly. This problem can be overcomed only by remeshing at several suitable stages. The present study aimed to establish the criterion based on the error estimators, and examined in the simulation and posterior error analysis of ring compression test to demonstrate the usefulness of them. The distribution of each error estimator and its variation during deformation were investigated. All the error estimators were increased monotonously with deformation and decreased rapidly at remeshing stage. It was shown that the error estimators suggested in this study are good measures as remeshing criterion for large deformation finite element analyses.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.66-76
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• 1999

Vehicle driving simulators have been used in the development and modification of models. A simulator can reduce cost and time through a variety of driving simulations in the laboratory. Recently, driving simulators have begun to proliferate in the automotive industry and the associated research community. This paper presents the hardware and software developed for a driving simulator of construction vehicles. This effor involves the real-time dynamic analysis of wheel-type excavator, the design and manufacturing of the Stewart platform, an integrated control system of the platform, and three-dimensional graphic modeling of the driving environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.976-987
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• 1998

In this paper, the effect of nonllinear distortion, caused by a high-power amplifier(HPA) in an orthogonal frequency division multiplexing (OFDM) system, on the receiver part is analyzed. Since the HPA, which can be modeled by a memeoryless Volterra system, distorts OFDM signals in a nonlinear fashion, the received signal at each subchannel includes the multiplicative distortion of 1-st order as well as additive nonlinear distortion of high-order. the nonlinear distortion can be viewed as a nonlinear interchannel interference (NICI) since it consists of harmonic distortions and intermodulation distortions, produced by oother subchannels affecting the subchannel of interest. In this paper, we analytically derive the variance of NICI in terms of average input power using the volterra model for HPA, and then calculate the bit-effor rate(BER) performance of an OFDM system. Also, we propose a simple method to compensate for the phase distortion in OFDM system amplified by HPA, OFDM system employing 16-QAM constellation input.

• 한국체육학회지인문사회과학편
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• v.51 no.3
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• pp.273-284
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• 2012

There is a large body of literature that studies serious leisure participants in a wide range of activities. By comparison, casual leisure has received scant attention, bearing few empirical studies. And serious leisure is often cast in an superior role in comparison with casual leisure for optimally healthy or beneficial leisure. The purpose of this study is to investigate the psychological functioning of 'casual leisure-serious leisure'. Especially, we pay more attention to reveal the positive functioning of casual leisure. It draws findings from the data of 291 university students. The results are as follows. First, in comparison with 'casual leisure group', 'serious leisure group' was showed a higher significant increase in leisure related functioning(leisure satisfaction and leisure benefits such as physical health, relationship and self-controlibility). However, There is no significant inter-group differences in 'self-life functioning variables(positive·negative self-esteem, happiness, quality of life)'. It implies even though serious leisure has more relation to positive leisure experiences, people maintain and enhance their self-esteem and experience satisfaction and happiness of their entire lives through casual leisure participation as much as serious leisure.