• 산업경영시스템학회지
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• 제36권4호
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• pp.25-30
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• 2013

This article deals with the transient analysis in bicycle shifting using a discrete chain model. Among the various components of a bicycle, we focused in the power-transmissions on the contact points between the chain element and sprocket. And by imposing kinematic motions on the front and rear derailleurs, we analyzed the shifting mechanism for increasing the rotational speed of rear wheel. In order to build the dynamic analysis model, we first tore down the real bicycle and measured each component's design parameters. Then we made 3-dimensional CAD models for each component related to the power transmission of a bicycle. Using the converted 3-dimensional dynamic model for the simulation program, we performed non-shifting and shifting dynamic analysis. As a result, we investigated the dynamic behaviors of a discrete chain model focused on the interaction between the chain and sprocket wheel.

• 한국정밀공학회지
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• 제17권10호
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• pp.125-131
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• 2000

By using the test of signal error, model structure of an electrohydraulic servo system is determined. For determining parameter of the electrohydraulic servo system, using time discrete model of parametric method, parameters in time discrete model are searched by the least square method. By bilinear transform, we have found the model of electrohydraulic servo system in s domain. Afterwards, we have compared experimental data with simulation data by MATLAB having the identified parameter. As the result, experimental data is agreed with simulation data very well.

• Journal of the Korean Statistical Society
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• 제31권2호
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• pp.177-198
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• 2002

The estimation of variance components or variance ratios in linear model is an important issue in plant or animal breeding fields, and various estimation methods have been devised to estimate variance components or variance ratios. However, many traits of economic importance in those fields are observed as dichotomous or polychotomous outcomes. The usual estimation methods might not be appropriate for these cases. Recently threshold linear model is considered as an important tool to analyze discrete traits specially in animal breeding field. In this note, we consider a hierarchical Bayesian method for the threshold animal model. Gibbs sampler for making full Bayesian inferences about random effects as well as fixed effects is described to analyze jointly discrete traits and continuous traits. Numerical example of the model with two discrete ordered categorical traits, calving ease of calves from born by heifer and calving ease of calf from born by cow, and one normally distributed trait, birth weight, is provided.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.318-322
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• 1996

In this study, a controller design method is proposed for controlling the discrete-time chaotic systems efficiently. Our proposed control method is based on Generalized Predictive Control and uses NARMAX models as a controlled model. In order to evaluate the performance of our proposed controller design method, a proposed controller is applied to Henon system which is a discrete-time chaotic system, and then the control performance of the proposed controller are compared with those of the previous model-based controllers through computer simulations. Through simulations, it is shown that the control performance of the proposed controller is superior to that of the conventional model-based controller.

• 대한의용생체공학회:의공학회지
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• 제16권4호
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• pp.415-424
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• 1995

Combined models, specified by two or more modeling formalisms, can represent a wide variety of complex systems. This paper describes a methodology for the development of combined models in two model types of discrete event and continuous process. The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can combine model of the DES and the CS within a framework. The structure employs the DEVS formalism for the DES models and differential or polynomial equations for the CS models. To employ the proposed structure to specify a DEVS/CS combined model, a modeler needs to take the following steps. First, a modeler should identify events in the CS and transform the states of the CS into the DES. Second, a modular employs the formalism to specify the system as the DES. Finally, a moduler developes sub-models for the CS and continguos states of the DES and establishs one-to-one correspondence between the sub-models and such states. The proposed formal structre has been applied to develop a DEVS/CS combined model for the human cardiovascular system. For this, the cardiac cycle is partitioned into a set of phases based on events identified through observation. For each phase, a CS model has been developed and associated with the phase. To validate the DEVS/CS combined model developed, then simulate the model in the DEVSIM + + environment, which is a model simulation results with the results obtained from the CS model simulation using SPICE. The comparison shows that the DEVS/CS combined model adequately represents dynamics of the human heart system at each phase of cardiac cycle.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.39-42
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• 2006

We propose a Bayesian model-based approach using a mixture of Dirichlet processes model with discrete wavelet transform, for curve clustering in the microarray data with time-course gene expressions.

• 대한전기학회논문지
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• 제35권8호
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• pp.333-340
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• 1986

This paper presents an approach for determining the discrete reduced-order models for largescale system by using matrix sign function. We define projection operators based on the matrix sign function and develop the algorithm for model-reduction by using them. Simulation studies show that the proposed altgorithm is very useful.

• 한국CDE학회논문집
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• 제18권3호
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• pp.224-233
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• 2013

For the scheduling and the job assignment of the ship hull production design which is a process-based work, we suggest the simulation-based scheduling using the discrete-event-based business process simulation. First, we analyze the ship hull production design process from the perspective of a job assignment to make it into the simulation model using DEVS (Discrete Event System Specification) which is the representative modeling method for a discrete-event simulation. Based on the APIs of the open-source discrete-event simulation engine, we implement the simulation using the Groovy script. We develop the scenario generator in which the user defines detail information of the construction drawing and its member blocks, and design engineers information, and the various setting for the simulation including the job assignment strategy. We use the XML files from this scenario generator as inputs of simulation so that we can get simulation result in forms of Gantt chart without changes of the simulation model.

• 한국도로학회논문집
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• 제18권2호
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• pp.51-60
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• 2016

PURPOSES : The applicability of the mechanics-based similarity concept (suggested by Feng et al.) for determining scaled variables, including length and load, via laboratory-scale tests and discrete element analysis, was evaluated. METHODS: Several studies on the similarity concept were reviewed. The exact scaling approach, a similarity concept described by Feng, was applied in order to determine an analytical solution of a free-falling ball. This solution can be considered one of the simplest conditions for discrete element analysis. RESULTS : The results revealed that 1) the exact scaling approach can be used to determine the scale of variables in laboratory tests and numerical analysis, 2) applying only a scale factor, via the exact scaling approach, is inadequate for the error-free replacement of small particles by large ones during discrete element analysis, 3) the level of continuity of flowable materials such as SCC and cement mortar seems to be an important criterion for evaluating the applicability of the similarity concept, and 4) additional conditions, such as the kinetics of particle, contact model, and geometry, must be taken into consideration to achieve the maximum radius of replacement particles during discrete element analysis. CONCLUSIONS : The concept of similarity is a convenient tool to evaluate the correspondence of scaled laboratory test or numerical analysis to physical condition. However, to achieve excellent correspondence, additional factors, such as the kinetics of particles, contact model, and geometry, must be taken into consideration.

• 정보처리학회논문지B
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• 제10B권6호
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• pp.639-646
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• 2003

본 논문은 일련의 불연속적인 도트 자극으로부터 시각적 착시현상을 추출하는 신경회로망 모델을 제시한다. 제안된 모델은 시각 정보처리 경로에서 발견되는 시각 세포들의 특성을 근거로 한다. 본 연구는 일련의 이산 도트 자극들이 개별적인 도트들로 인식하지 않고 연속적인 가상의 윤곽으로 인식하는 시각적 착시 현상을 나타내는 생리심리학 실험을 기초로 하여 도트 자극의 시각적 착시를 구현한 것으로서 실험에서는 가상 다각형 형태로 배치된 6에서 10개의 도트자극들을 사용한다. 이 실험 데이터는 Smith & Vos가 생리심리학적 실험에서 다룬 데이터와 유사하다. 제안된 모델은 이산 도트자극으로부터 연속적인 착시 윤곽을 성공적으로 추출한다.