• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.180-185
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• 2008

A new method for relative error continuous and discrete time model order reduction is proposed. The reduction technique is based on two recently developed methods, namely frequency domain balanced truncation within a frequency bound and inner-outer factorization techniques. The proposed method is of interest for practical model order reduction because in this context it shows to keep the accuracy of the approximation as high as possible without sacrificing the computational efficiency. Numerical results show the accuracy and efficiency enhancement of the method.

• 제어로봇시스템학회논문지
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• 제12권3호
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• pp.227-232
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• 2006

In this paper, we propose a systematic method for intelligent digital redesign of a fuzzy-model-based controller for continuous-time nonlinear system which may also contain system uncertainties. The continuous-time uncertain TS fuzzy model is first contructed to represent the uncertain nonlinear system. A parallel distributed compensation(PDC) technique is then used to design a fuzzy-model-based controller for both stabilization. The designed continuous-time controller is then converted to an equivalent discrete-time controller by using a globally intelligent digital redesign method. This new technique is designed by a global matching of state variables between analog control system and digital control system. This new design technique provides a systematic and effective framework for integration of the fuzzy-model-based control theory and the advanced digital redesign technique for nonlinear systems with uncertainties. Finally, Chaotic Lorenz system is used as an illustrative example to show the effectiveness and the feasibility of the developed design method.

• 한국위성정보통신학회논문지
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• 제12권1호
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• pp.28-33
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• 2017

본 논문에서는 여러 곳에서 통용되고 있는 기존의 CW(continuous-wave) 레이더 송수신모델을 수정한 송수신모델을 제안한다. 최근에 심장박동과 호흡을 검출하기 위해 기존신호모델을 기반으로 CW(continuous-wave) 레이더에 대한연구가 진행 되고 있다. 그러나 이 통용되고 있는 수신모델은 인체 공학적으로 개념과 일치하지 않기 때문에 이모델을 근거로 실험을 할 경우 실제 개발되는 시스템 성능을 정확하게 예측할수 없다. 본 논문에서는 인체 공학상 개념과 일치하는 수정된 CW(continuous-wave) 레이더 송수신모델을 제안하고 가운시안 잡음rhk 다중경로 환경에서 심장박동 및 호흡검출에 대한 시뮬레이션을 수행하고 이를 기존수신모델과의 심장박동과 호흡검출에 대한 성능을 비교 분석한다.

• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.25-32
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• 1995

단어인식의 성능향상을 위하여 평행분기 음성단위(subunit) 모델의 사용을 제안하였으며 연속 분포 HMM에서 이 모델은 각 음성단위를 확률분포함수 (mixture components)를 이용하여 분기시킴에 의해 얻어진다. 제안된 방법을 사용한 결과에 따르면 기존에 제안된 평행분기 [1] 음성단위 모델이나 단일분기 모델보다 높은 인식률을 얻을 수 있었다. 본 연구에서는 각 음성단위에 대해 활률분포함수나 분기수의 적절한 결합을 통해 높은 인식률을 얻는데 이 1036 한국어 결리단어가 인시실험에 사용되었다.

• 한국철도학회논문집
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• 제8권1호
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• pp.82-86
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• 2005

Numerical methods to estimate behaviors of jointed rock mass can be roughly divided into two methods : continuous and discontinuous model. Generally, distinct element method(DEM) is applied in discontinuous model, and finite element method(FDM) or finite difference method(FDM) is utilized in continuum model. To predict a behavior of discontinuous model by DEM, it is essential to understand characteristics of joints developed in rock mass through field tests. However, results of field tests can not provide full information about rock mass because field tests are conducted in limited area. In this paper, discontinuous analysis by UDEC and continuous analysis by FLAC are utilized to estimate a behavior of a tunnel in jointed rock mass. For including discontinuous analysis in continuous analysis, joints in rock mass is considered by reducing rock mass properties obtained by RMR and decreasing shear strength of rock mass. By comparing and revising two analysis results, analysis results similar with practical behavior of a tunnel can be induced and appropriate support system is decided.

• 한국정보시스템학회지:정보시스템연구
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• 제31권2호
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• pp.197-216
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• 2022

Purpose In this study, in order to understand the effects of NTIS users' behavioral scientific behaviors and determinants, an integrated model of the UTAUT(Unified Theory of Acceptance and Use of Technology) model and TTF(Task-Technology Fit) model, which are frequently used MIS field, was presented and empirical analysis was conducted. Design/methodology/approach In this study, an online survey was conducted on researchers from organizations carrying out national R&D projects, institutions, universities, and dedicated management institutions and the collected data verified hypotheses established using the SPSS 25.0 statistical package and structural equation model using AMOS. Findings The results showed that NTIS users' business activities had a positive(+) effect on task-technology fit and task-technology fit had a positive(+) effect on performance expectation, effort expectation, and continuous intention-to-use intention. In addition, the performance expectation, effort expectation, and promotion conditions presented in research model had a positive(+) effect on the continuous intention-to-use. The research results derived through this study are expected to contribute substantially to subsequent research in the field related to information sharing platforms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1883-1887
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• 1991

Identification theory for linear discrete system has been presented by a great many reference, but research works for identification of continuous-time system are less than preceding identification. In fact, a great man), systems for engineering are continuous-time systems, hence, research for identification of continuous-time system has important meaning. This paper offers the following results: 1. Corresponding relations for the parameters of continuous-time model and discrete model may be shown, when single input-output system has general characteristic roots. 2. To do identification of single variable continuity linear system with stability constraints from samples of input-output data, it is necessary to use optimization with stability constraints. 3. Main results of this paper may be explained by a simple example.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.466-471
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• 2004

Efficient numerical finite element analysis of creeping concrete structures requires the use Kelvin or Maxwell chain model, which is most conveniently identified from a continuous retardation or relaxation spectrum, the spectrum in turn being determined from the given compliance or relaxation function. The method of doing that within the context of solidification theory for creep with aging was previously worked out by Bazant and Xi, but only for the case of a continuous retardation spectrum based on Kelvin chain. The present paper is motivated by the need to incorporate concrete creep into the recently published microplane model M4 for nonlinear triaxial behavior of concrete, including tensile fracturing and behavior under compression. In that context. the Maxwell chain is more effective than Kelvin chain. because of the kinematic constraint of the microplanes used in M4. Determination of the continuous relaxation spectrum for Maxwell chain. based on the solidification theory, is outlined and numerical examples are presented.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.30-34
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• 2000

In this paper we analyzed bulging condition which affect the quality of continuous casting steel by using the numerical analytic method. First solidification analyses are performed for each cooling zones. Solidification analysis are carried out by one-dimensuional finite difference method. The bulging deformation of cast slab has been calculated with a two-dimensional elasto-plastic and creep finite element model. The adequacy of the model has been checked against the experimental results. From this study the effects of the process variables such as casting speed cooling condition roll pitch are examined. The results from these analyses would be able to apply to the design of continuous casting process.

• Journal of Information Technology Applications and Management
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• 제19권4호
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• pp.61-74
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• 2012

This studies aims to examine the factors that affect continuous usage reliability of social commerce users that has been really active recently based on using EDT (Expectation Disconfirmation Theory) and extended ECM (Expected confirmation Model). With a statistical analysis, this paper suggests a conceptual model, based on the empirical evidence from this study. The result reveal that perceived usage easiness has a positive effect on meeting the expected confirmation and satisfaction. As perceived quality, social influence and price appeared to reflect a positive effect on fulfilling expected confirmation. This implies that users consider perceived usage easiness, perceived quality, social influence and price important in using social commerce persistently and that as their expected confirmation fulfillment and satisfaction increase that leads to further rise in their future intended continuous usage.