• Journal of Institute of Control, Robotics and Systems
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• v.14 no.5
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• pp.489-495
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• 2008

This paper offers a practical control scheme for driving mode transformation of a rescue robot already developed. The rescue robot, VSTR(Variable Single-Tracked Robot), has two driving modes, so can traverse untidy terrain and overcome obstacles such as stairs easily by use of timely driving mode transformation. Classical PI control scheme was used firstly for driving mode transformation, but stationary phenomenon, which might have a bad effect on the performance in real situation, came into existence. Therefore, we suggest a new controller, PI-based feedforward controller, which should be a good alternative for the problem, and compare it with other nonlinear control scheme.

• Proceedings of the Korean Association for Survey Research Conference
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• 2001.11a
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• pp.77-85
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• 2001

In this paper we study the calibration estimator and its variance estimator for the population total using a bootstrap method according to the levels of an auxiliary information having strong correlation with an interested variable in nonresponse situation. At this point, we find tire calibration estimator in case of auxiliary information for population and sample, and then we drive the bootstrap variance estimator of it. By simulation study we compare the efficiencies with the Taylor and Jackknife variance estimators.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.14
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• pp.219-233
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• 2000

Korea has been faced a difficult situation with regard to the cost of physical distribution(PD). The problem have arisen from the fact that Korean firms have far different cost structures of the PD according to its industry or business. High PD costs sometimes reduce firms' operating income and perceived competitive disadvantages not only in domestic but in world-wide business. In this research, we examine the factors affecting firm's PD cost by investigating financial and non-financial variables such as variable cost to sales ratio and number of employee of a firm. Analyses are performed to construct research models with t-test and the logistic regression estimation.

• Communications for Statistical Applications and Methods
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• v.9 no.2
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• pp.479-489
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• 2002

The case which applies two-phase sampling to stratification and nonresponse problem, it is a poweful and effective technique. In this paper we study the calibration estimator and its variance estimator for the population total using two-phase sampling method according to the of auxiliary information for population and sample having strong correlation with an interested variable in unit nonresponse situation. The auxiliary information that available both at first-phase and second-phase sampling can be used to improve weights by the calibration procedure. A weight which corresponds to the product of sampling weights and response probability is calculated at each phase of sampling.

• Journal of Family Resource Management and Policy Review
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• v.1 no.1
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• pp.79-88
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• 1997

The purpose of this study is to identify the situation of leisure preferences, the effect of related variables on the leisure preferences, and the relationship between leisure preferences and participations of urban married women. The survey of this research was conducted by means of interviews with 606 married women in Seoul. The instruments of the survey were questionnaires including a leisure preferences scale. Data were analysed by means of the statistics of frequency, mean, standard deviation, ANOVA, and Sheffe’s multiple range test, using the SPSS program. The results were as follows: The most preferred leisure type by urban married women is family oriented activities, especially conversations with family and playing with children. The level of leisure preferences differs according to related variables. The most distinctive variable on leisure preferences is the sex role of women. The relationship between leisure preferences and participations differs according to leisure activities and types. Especially in the area of religion/ social activities and self-developing activities, preferences on leisure activities has relatively strong relationship with participations on leisure activities.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.105-108
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• 1997

We developed a FLC(Fuzzy Logic Controller) for tracking control of MR(Mobile Robot) with obstacle avoidance. In this research, we made a heuristic approach to tracking control which is simple and efficient in almost every situation using FLC. In addition, smooth turn is accomplished and also obstacles are avoided. Also we used the XX(don't care) linguistic variable for inputs in FLC to make simple rule-table. With various simulations, the validity of our FLC was shown.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.415-420
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• 2012

It is important to understand the amount of time required to execute an emergency procedural task in a high-stress situation for managing human performance under emergencies in a nuclear power plant. However, the time to execute an emergency procedural task is highly dependent upon expert judgment due to the lack of actual data. This paper proposes an analytical method to estimate the operator's performance time (OPT) of a procedural task, which is based on a measure of the task complexity (TACOM). The proposed method for estimating an OPT is an equation that uses the TACOM as a variable, and the OPT of a procedural task can be calculated if its relevant TACOM score is available. The validity of the proposed equation is demonstrated by comparing the estimated OPTs with the observed OPTs for emergency procedural tasks in a steam generator tube rupture scenario.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.95-98
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• 2010

본 논문에서는 소프트웨어 개발 프로세스 분석 도구인 4-DAT를 이용하여 범용적으로 사용되고 있는 애자일 프로세스인 XP와 스크럼을 비교분석하였고, 게임 개발 프로세스를 평가하기 위한 평가 알고리즘을 제안한다. 새로운 개발 방법 평가 알고리즘은 기존의 4-DAT가 포함하고 있는 4차원의 고려사항을 3차원으로 재정의하여 통합한 것으로, 게임 개발 환경에서 기존의 XP와 스크럼이 가지는 제약성을 보완할 수 있고, 게임 개발을 위한 프로세스의 도입에 있어 부족한 요소를 추출할 수 있다. 실험의 방법으로서 실제 개발한 모바일 게임의 주기와 실행방법을 분석하여 5항목의 상황변수를 정의하였고, 4-DAT가 가지는 기준에 적용하여 기초 자료를 도출하여, 재구성한 3-DAT를 기반으로 정의된 상황변수를 적용하여 분석하였다. 그 결과 6가지의 상황에 따른 데이터를 구하였으며, 이를 종합하여 게임 개발에 적합한 프로세스의 요구사항을 알 수 있었다.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.129-138
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• 2006

The motion of a spinning table-tennis ball is investigated in both theory and experiment. The equation of motion of spinning table-tennis ball is made using aerodynamics and calculated by C++ program In theoretical part, gravity, drag force and lift force are regarded as main force. Velocity, angular velocity, mass and Drag and lift coefficients are considered as a independent variable. Experiments are made by a digital stroboscope, a digital camera and a mirror, and snap multi-exposed images were took as a dependent result In experimental part, both magnitude and direction of velocity and angular velocity are changed in each situation. The predicted three-dimensional trajectories of spinning balls are compared with experimental trajectories. As a result the theoretical trajectories were predicted within 10% of experimental trajectories.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.3
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• pp.176-187
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• 1998

The Dismantlement and Construction of the buildings have the characteristic of floating change with repetition within a Time Schedule which has fixed resources, that is, Manpower, Materials and Equipments, and involve many disaster factors in performing each processes. But as these factors are variable, a work supervisor should be able to understand data analysed distinctive factors of each activities systematically, organizationally, and scientifically, and diagrammatic information media so that he can control any complex and situation beyond forecast. Thus this study is intended to be a barometer of weighing if the existing process schedule has taken security into consideration by making the characteristics of organization and action of Work package per process in a building field with more factors like these into a network system and is intended to minimize construction disasters by systematizing this into a Transformational Network.