• 한국정밀공학회지
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• 제8권2호
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• pp.57-68
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• 1991

In this study, to analyse the dynamic characteristics of a machine-tool spindle system, the spindle is mathematically represented by a Timoshenko beam including the internal damping of beam material, and each bearing by four bearing coefficients; stiffness and damping coefficients in moment and radial directions. And the dynamic compliance of the system is calculated by introducing the transfer matrix method, and the complex modal analysis method has been applied for the modal parameter identification. The influence of the bearing coefficients, material damping factor and bearing span on the dynamic characteristics of the system is parametrically examined.

• Ocean Systems Engineering
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• 제5권3호
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• pp.199-220
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• 2015

The paper described the nonlinear dynamic motion behavior of a barge equipped with the portable outboard Dynamic Positioning(DP) control system in short-crested waves. The DP system based on the fuzzy theory is applied to control the thrusters to optimally adjust the ship position and heading in waves. In addition to the short-crested waves, the current, wind and nonlinear drifting force are also included in the calculations. The time domain simulations for the six degrees of freedom motions of the barge with the DP system are solved by the $4^{th}$ order Runge-Kutta method. The results show that the position and heading deviations are limited within acceptable ranges based on the present control method. When the dynamic positioning missions are needed, the technique of the alternative portable DP system developed here can serve as a practical tool to assist those ships without equipping with the DP facility.

• 수산해양기술연구
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• 제54권2호
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• pp.181-187
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• 2018

In order for the probe to perform ocean exploration and survey research, it is necessary to adjust the position of the ship as desired by dynamic positioning system. The dynamic positioning system of T/S NARA is applied to K-POS dynamic positioning system of Kongsberg, which makes maintaining the ship's position, changing position and heading control possible. T/S NARA is not capable of dynamic positioning if one or more propulsive forces are lost with DP Level One. However, it is predicted that dynamic positioning can be achieved even at the time of missing one thrust in a good sea condition. Therefore, we want to analyze the effect of each propulsion on the performance of dynamic position system. When one of the bow thruster and azimuth thrusters lost their propulsion, maintaining the ship's position, changing position and heading control performance were compared and analyzed. If the situation occurred disable from using the bow thruster, they can not maintain ship's position. Azimuth thruster was influential for the ship's position control and bow thruster was influential in heading control. The excellent dynamic positioning performance can be achieved, considering the propulsion power that will have a impact on each situation in the future.

• 한국통신학회논문지
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• 제24권10A호
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• pp.1546-1554
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• 1999

본 논문에서는 결함 및 마스크, 스위칭 기능을 포함한 결함에 대한 동적 구조를 갖는 결함 허용 시스템에 대하여 신뢰도 평가를 할 수 있는 동적 결함 트리 알고리듬(Dynamic Fault Tree Algorithm)을 제안한다. 본 알고리듬에서는 동적 특성을 표현할 수 있는 FDEP, CSP, SEQ, PAG 게이트 정의로부터 출발한다. 이러한 게이트의 정의는 시스템의 동적 특성을 만족시키기 위해 시스템의 상태증가를 유발하는 기존의 마코브 모델과 시스템의 정적 특성에 대해서만 평가 가능했던 결함 트리 모델에 대한 제약조건을 해결할 수 있었다. 본 논문에서는 제시한 알고리듬의 장점을 입증하기 위하여 동적 특성을 가지는 TMR(Triple Modular Redundancy) 시스템과 이중화 중복 시스템(Dual Duplex System)에 대해 기존의 알고리듬과 제시하는 알고리듬을 적용하여 신뢰성 평가를 수행한 후 이를 통해 제시하는 알고리듬이 동적 여분을 사용하는 시스템이나 순차 종속 고장들을 가지는 시스템, 결함과 오류의 복구 기술을 가지는 시스템들에 대해 우수함을 보여준다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.485-491
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• 2000

We obtain the mathematical model of the hard disk drive actuator system from the system response data of the finite element analysis or experimental results. System response data including the dynamics of the considered system are expressed as the mathematical model. It allows the dynamic analysis of the actuator system without resort to the repetitive finite element modeling work. Even though the dynamic characteristics of the system are affected somewhat by the structural modification and the change of the dynamic properties, we can use the modified size and material properties of the actuator system in the mathematical model to some extent. In this study, we express the mathematical model of the simplified rectangular plate first and then proceed to the actual hard disk drive actuator system.

• 대한전기학회논문지:전력기술부문A
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• 제50권1호
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• pp.6-12
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• 2001

This paper deals with the development of dynamic equivalents of the Korea Electric Corporation (KEPCO) systems. The weak coupling method is chosen for the most suitable coherency identification to represent the characteristics of the KEPCO system by the dynamic characteristic comparison of several coherency identification methods. Also, this paper shows the detail aggregation of generator groups makes a better representation of the dynamic and static characteristics of the original system than the classical aggregation. The simulation results of the developed KEPCO equivalent system are presented in comparison with the original system to illustrate the validity of the equivalent system are presented in comparison with the original system to illustrate the validity of the equivalent system.

• 디지털산업정보학회논문지
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• 제6권3호
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• pp.211-219
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• 2010

This paper designs the dynamic symbol automatic trading system in Korean option market. This system is based on Multichart program which is convenient and efficient system trading tool. But the Multichart has an important restriction which has only one constant symbol per chart. This restriction causes very useful strategies impossible. The proposed design uses global variables, signal chart selection and position order exchange. So an automatic trading system with dynamic symbol works on Multichart program. To verify the proposed system, BS(Buythensell)-SB(Sellthenbuy) strategies are tested which uses the change of open-interest of stock index futures within a day. These strategies buy both call and put option in ATM at start candle and liquidate all at 12 o'clock and then sell both call and put option in ATM at 12 o'clock and also liquidate all at 14:40. From 23 March 2009 to 31 May 2010, 301-trading days, is adopted for experiment. As a result, the average daily profit rate of this simple strategies riches 1.09%. This profit rate is up to eight times of commision price which is 0.15 % per option trade. If the method which raises the profitable rate of wining trade or lower commission than 0.15% is found, these strategies make fascinated lossless trading system which is based on the proposed dynamic symbol automatic trading system.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권9호
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• pp.512-519
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• 2000

A Neural networks has been used for a expert system and fault diagnosis system. It is possible to nonlinear function mapping and parallel processing. Therefore It has been developing for a Diagnosis system of nuclear plower plant. In general Neural Networks is a static mapping but Dynamic Neural Network(DNN) is dynamic mapping.쪼두 a fault occur in system a state of system is changed with transient state. Because of a previous state signal is considered as a information DNN is better suited for diagnosis systems than static neural network. But a DNN has many weights so a real time implementation of diagnosis system is in need of a rapid network architecture. This paper presents a algorithm for RCP monitoring Alarm diagnosis system using Self Dynamic Neural Network(SDNN). SDNN has considerably fewer weights than a general DNN. Since there is no interlink among the hidden layer. The effectiveness of Alarm diagnosis system using the proposed algorithm is demonstrated by applying to RCP monitoring in Nuclear power plant.

• 전기의세계
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• 제24권5호
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• pp.67-71
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• 1975

A dynamic stability analysis of a large interconnected power system takes much time even though the modern large computer is used because of the high order of the system dynamic equations. By the necessity of the low order power system models, a simplified power system model of the generator with the high speed solid state exciter is developed in this paper. The usefulness of the reduced model is confirmed by comparing its eigenvalues and the transient responses with those of the original model in the single machine to infinite bus power system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.187-189
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• 2001

In this paper, we have simulated the transient stability of power system with dynamic loads. Dynamic load characteristics have an important influence on power system stability. In study of power system stability, motors form a major portion of the system loads. Induction motors and synchronous motors in particular form the workhorse of the electric power industry. Therefore modelling of motors is important in system stability. We investigate the effect of motors loads of Kwang Yang network with three phase fault.