• 제어로봇시스템학회논문지
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• 제6권6호
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• pp.433-440
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• 2000

To flexibly evaluate performance and reliability of a real-time system which is intrinsically characterized by stringent timing constraints to generate correct responses, we propose fuzzyrandom variables and build a discrete event model embedded with fuzzy-random variables. Also, we adapt fuzzy-variables to a path-space approach, which derives the upper and lower bounds of reliability by using a semi-Markov model that explicitly contains the deadline information. Consequently, we propose certain formulas of state automata properly transformed by fuzzy-random variables, and present numerical examples applying the formulas to RTP(Rapid Thermal Process) to show that a complex system can be properly evaluated based on this model by computer simulation.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권7호
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• pp.363-369
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• 2000

To flexibly evaluate performance and reliability of an electric power system in the aspect of the real-time system which is intrinsically characterized by stringent timing constraints fails catastrophically if its control input is not updated by its digital controller computer within a certain time limit called the hard deadline, we propose fuzzy-random variables and build a discrete event model embedded with fuzzy-random variables. Also, we adapt fuzzy-variables to a path-space approach, which derives the upper and lower bounds of reliability by using a semi-Markov model that explicitly contains the deadline information. Consequently, we propose certain formulas of state automata properly transformed by fuzzy-random variables, and present numerical examples applying the formulas as well.

• 한국식생활문화학회지
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• 제25권6호
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• pp.755-763
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• 2010

The purpose of this study was to select market variables that a foodservice company should consider when expanding overseas and to regional market analysis by variables. Twenty-three different variables were derived from 17 previous studies. These were: population, urbanization rate, women employed, enrollment in tertiary education, gross domestic product, value added by service, total number of mobile cellular telephone subscribers, number of internet users, total Asian highway, inward foreign direct investment, total service imports, inflation rate, international tourist arrivals, energy use by industry, growth rates of the food consumer price index, access to urban sanitation, per capita total expenditure on health, male life expectancy at birth, adult literacy rate, contributing women family workers, passenger car, and country risk assessment. The selected variables were collected as secondary data from the UN, Asian Development Bank, International Bank for Reconstruction and Development, and Michigan State University.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.352-356
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• 1990

In this paper proposed a new analysis method that can be controlled DC separately excited motor using DC chopper. An analysis method can be broadly divided the state variables method and the state space averaging method. The state variable method is largely used for analysis method in the time area, but it is complicated analysis of the nonlinear circuit and modeling of the system. Therefore a boundary of the current continuous mode and discontinuous mode can be definited by the state space averaging method. Also this paper proposed a new approximation analysis method using state space averaging method in the discontinuous mode.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1-6
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• 1991

This paper is concerned with the design of a robust tracking controller using a state observer on a robotic manipulator under the disturbance. The controller is designed to follow a step or ramp reference input without steady state error in the presence of a disturbance and a system parameter variation. In most cases, since all the state vectors are not measured, unmeasurable state vectors must be estimated or reconstructed. A reduced order observer is proposed to estimate unmeasurable state vectors of the non-linear system. Some problems are caused by the Coulomb friction, the disturbance, and the spring effect of a link between the drive motor and the manipulator arm. The state variables, directly measured and estimated by the reduced order observer, are fed back to the controller. When the robot system exhibits the 'limit cycle, the feedback gains initially obtained by optimal control theory are changed. As a result, the limit cycle is eliminated by the new controller gains,

• 전기의세계
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• 제22권3호
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• pp.49-62
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• 1973

An algorithm for the state estimation and identification of multivariable nonlinear systems with noisy nonlinear observation has been investigated on the basis of the multidimensional Hermitian expansion for the a posteriori probability densities of the predicted observation, the predicted state and the observation conditioned by the state. A new approach for construction of this sequential nonlinear estimator, retaining up to the second order term of the observation error, has been developed, along with the approximation of nonlinear system functions, truncating at the second term. The estimation of the unknown parameters has been established by extending the state estimation technique, regarding the parameters as another state variables. The results of investigation indicate the feasibility of the schemes presented in this paper.

• 한국시뮬레이션학회논문지
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• 제21권1호
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• pp.27-34
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• 2012

본 논문의 목적은 복잡한 군수지원시스템의 모델링과 시뮬레이션을 위한 방법론을 제안하는 것이다. 제안하는 군수지원시스템 시뮬레이션 모델을 구성하는 요소들은 세 가지가 있다 : Logistics force agent(static model), Military supplies transport manager(function model), Military supplies state manager(dynamic model). Logistics force agent는 main function agent와function agent로 구성된다. Function agent가 다른 Logistics force agent에도 적용할 수 있도록 설계되었으며, 이는 에이전트의 높은 조합성과 재사용성을 가진다. Military supplies transport manager는 보급로에 대한 정보를 가지며 military supplies state manager로부터 받은 결정변수를 기반으로 보급로를 결정하고 군수품을 수송하는 역할을 하는 에이전트이다. Military supplies state manager는 군수품 보급을 요청받고 보급량, 우선순위 따위의 결정 변수를 military supplies transport manager에게 알려주는 역할을 한다. 본 논문에서는 군수 시뮬레이션 모델의 설계를 위해 Discrete Event Systems Specification(DEVS) formalism을 이용하였다.

• 대한물리치료과학회지
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• 제15권2호
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• pp.41-51
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• 2008

Background: The purpose of this study is to determine how the cognitive state of the elderly influences the activities of daily living(ADL) in order to increase their achievement capacity and their ability to exercise this capacity in daily life. The MMSE-K(Mini-Mental State Examination-Korean) was used to evaluate the daily activities and cognitive state of a group of subjects more than 65 years of age. The goal was to understand (1) How their achievement level in their daily activities changes according to the increase and decrease of their cognition points by analyzing and comparing their achievement points in the mental state examination, and (2) What variables influence that daily achievement level. Methods: The survey was conducted by a group of students from AnSan College who were trained for this method of data collection. The group surveyed 224 senior citizens older than 65 to determine their ADL performance. The subjects were selected from Silver Care Centers in the Gyounggi Province area including centers in Suwon, Anyang, Kwachun, and Sanbon City. The subjects were given enough information to fully understand the purpose of the study and the method by which it would be conducted. The survey method was a direct interview: which involved an interviewer reading the questionnaire to the subject and recording the answer. Result: The following results were calculated using SPSS WIN ver. 13.0: In the lower score of the MMSE-K regarding ADL performance (K-MBI) for activities such as individual hygiene, bathing activity, food activity, toilet management, going up stairs, getting dressed ad undressed, controlling stools and urination, walking, and chair/bed movement, most of the subjects responded that they could not perform these activities by themselves (p<.01). In the higher scores for the same activities, most response that they could perform the tasks by themselves (p<.01). In the results of the multiple regression analysis, there influence of the variables for ADL performance (K-MBI) and MMSE-K score was higher for females than males. Conclusion: This study evaluated the cognitive state of the elderly using the MMSE-K, which is the most convenient method, and examined how the cognitive state influences the achievement capacity of the daily lives with other variables. In conclusion, the higher the score on the MMSE-K, the more independent the elders are in the activities of daily living, especially among women more than men.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.409-416
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• 2004

An active modal-fuzzy control method using hydraulic actuators is presented for seismic response reduction. In the proposed control system, a new fuzzy controller designed in the modal space produces the desired active control force. This type controller has all advantages of the fuzzy control algorithm and modal approach. Since it is very difficult to select input variables used in fuzzy controller among an amount of state variables in the active fuzzy control system the presented algorithm adopts the modal control algorithm which is able to consider more easily information of all state variables in civil structures that are usually dominated by first few modes. In other words, all information of the whole structure can be considered in the control algorithm evaluated to reduce seismic responses and it can be efficient for especially civil structures. In addition, the presented algorithm is expected to magnify utility and performance caused by efficiency that the fuzzy algorithm can handle complex model more easily. An active modal-fuzzy control scheme is applied together with a Kalman filter and a low-pass filter to be applicable to real civil structures. A Kalman filter is considered to estimate modal states and a low-pass filter was used to eliminate spillover problem. The results of the numerical simulations far a wide amplitude range o f loading conditions and for historic earthquakes having various frequency components show that the proposed active modal-fuzzy control system can be beneficial in reducing seismic responses of civil structures.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.565-569
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• 2006

The purpose of this study was to assess the influence of the presence and impacted state of the mandibular third molars on the incidence of mandibular condyle fracture. A retrospective study was designed for patients presenting to the Department of Oral and Maxillofacial Surgery, Kyungpook National University Hospital and Tae-gu Fatima Hospital for treatment of mandibular fractures from January 2003 to January 2006. The independent variables in this study were the presence, degree of impaction of third molars, and the outcome variables were the incidence of mandibular condyle fractures. Hospital charts and panoramic radiographs were used to determine and classify these variables. The demographic data included age, sex, mechanisms of injuries and number of mandibular condyle fractures. The study sample comprised 136 mandibular condyle fractures in 105 patients. Result of this study demonstrated a statistically significant difference in ipsilateral condyle fractures and mandibular third molar absence(P=0.032) and bilateral condyle fractures without another fracture and mandibular third molar absence(P=0.028).