• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1890-1901
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• 2022

We have assessed the applicability of the thermal-hydraulic system analysis code, SPACE, to a small modular reactor called SMART. For the assessment, the experimental data from a scale-down integral-test facility, SMART-ITL, were used. It was conformed that the SPACE code unrealistically calculates the safety injection flow rate through the CMT and SIT during a small-break loss-of-coolant experiment. This unrealistic behavior was due to the overprediction of interfacial heat transfer at the steam-water interface in a vertically stratified flow in the tanks. In this study, a special thermal-hydraulic component model has been developed to realistically calculate the interfacial heat transfer when a strong non-equilibrium two-phase flow is formed in the CMT or SIT. Additionally, we developed a special heat structure model, which analytically calculates the heat transfer from the hot steam to the cold tank wall. The combination of two models for the tank are called the special component model. We assessed it using the SMART-ITL passive safety injection system (PSIS) test data. The results showed that the special component model well predicts the transient behaviors of the CMT and SIT.

• 한국정밀공학회지
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• 제14권11호
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• pp.135-146
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• 1997

This paper describes fault diagnosis method in complex system with hierachical structure similar to human body structure. Complex system is divided into unit, item and component. For diagnosing this hierarchical complex system, it is necessary to implement special neural network. Fault diagnosis system can forecast faults in a system and decide from current machine state signal information. Comparing with other diagnosis system for single fault, the developed system deals with multiple fault diagnosis comprising Hierarchical Neural Network(HNN). HNN consists of four level neural network, first level for item fault symptom classification, second level for item fault diagnosis, third level for component symptom classification, forth level for component fault diagnosis. UNIX IPC(Inter Process Communication) is used for implementing HNN wiht multitasking and message transfer between processes in SUN workstation with X-Windows(Motif). We tested HNN at four units, seven items per unit, seven components per item in a complex system. Each one neural newtork operate as a separate process in HNN. The message queue take charge of information exdhange and cooperation between each neural network.

• 한국콘텐츠학회논문지
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• 제11권4호
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• pp.225-234
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• 2011

본 연구는 교육기반 작업치료 서비스 전문가가 사용하는 중재모델, 중재장소와 중재시간, 중재모델 선택시 고려사항, 중재모델과 중재 영역 간에 상관관계를 알아보기 위해 특수교육지원센터에 근무하고 있는 작업치료사와 작업치료를 전공한 치료교사를 대상으로 설문지를 발송하고, 회수한 총 46부를 분석에 사용하였다. 연구결과 첫째, 학생의 수행 기술을 향상시키는데 초점을 둔 개별치료 모델을 자주 사용하였다. 둘째, 아동수행을 향상시키는 중재모델과 다른 팀 전문가에게 작업치료의 중요성을 인식시킬 수 있는 모델로 개별 치료를 선택하였다. 셋째, 중재모델을 선택하는 요인으로 수행구성요소의 결함과 팀 책임자의 마인드를 들었다. 넷째, 중재모델의 효과성에 대한 학교작업치료사의 의견과 적용시간, 중재 영역과 중재모델 적용시간 간에 유의한 상관관계는 나타나지 않았다. 연구결과를 종합해 보면 학교기반 작업치료사는 여전히 의료모델에 가까운 중재모델을 사용하는 것으로 나타나 학교기반에 효과적인 중재모델을 개발하고 적용하는 연구가 필요할 것이라 생각된다.

• 한국해양공학회지
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• 제7권1호
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• pp.62-72
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• 1993

This paper describes the results of 3 years project on the design and development of a 500 meter class ocean survery ROV model. The design concept and the design procedure are given for each component of the ROV model. The design concept and the design procedure are given for each component of the ROV. Special emphasis is laid on the development of the position control system together with the development of the performance evaluation technique.

• 한국산학기술학회논문지
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• 제6권6호
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• pp.536-541
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• 2005

고무 성분에 대한 대변형 및 강성은 비선형 및 대변형의 해석 결과로 나타낼 수 있다. 또한 고무는 Mooney-Rivlin의 모델로서 적용되고 고무들 사이에서 자기 접촉이 성립되어지는데 강성체 및 고무 사이에서는 마찰력이 있게 된다. 본 연구에서 사용된 비선형 시뮬레이션 해석은 여러 가지의 고무 성분들의 설계, 분석 그리고 개발에 널리 사용될 수 있다. 이러한 방법을 이용하면 새로운 고무 제품을 개발하는데 있어서 시간과 비용을 절감할 수 있을 것으로 보인다. 고무 성분들의 분석은 특이한 재료의 모델링과 비선형 유한 요소 해석을 요하는데 금속 부품들에 대하여 해석하는 프로그램들과는 완전히 다르다. 본 연구의 목적은 대변형 및 비선형의 고무 부품을 해석하는데 있다.

• 품질경영학회지
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• 제18권1호
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• pp.129-147
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• 1990

This study is to refer to the optimization problems when the stress and strength follow the time dependent model, considering a decision making process in the design methodology from reliability viewpoint. Reliability of a component can be expressed and computed if the probability distributions for the stress and strength in the time dependent case are known. The factors which determine the parameters of the distributions for stress and strength random variables can be controlled in design problems. This leads to the problem of finding the optimal values of these parameters subject to resources and design constraints. This paper is to present techniques for solving the optimization problems at the design stage like as minimizing the total cost to be spent on controlling the stress and strength parameters for random variables subject to the constraint that the component must have a specified reliability, alternatively, maximizing the component reliability subject to certain constraints on amount of resources available to control the parameters. The derived expressions and computations of reliability in the time dependent case and some optimization models of these cases are discussed. The special structure of these models is exploited to develop the optimization techniques which are illustrated by design examples.

• 음성과학
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• 제10권4호
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• pp.149-157
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• 2003

In this paper, we proposed the principal component analysis (PCA) fuzzy mixture model for speaker identification. A PCA fuzzy mixture model is derived from the combination of the PCA and the fuzzy version of mixture model with diagonal covariance matrices. In this method, the feature vectors are first transformed by each speaker's PCA transformation matrix to reduce the correlation among the elements. Then, the fuzzy mixture model for speaker is obtained from these transformed feature vectors with reduced dimensions. The orthogonal Gaussian Mixture Model (GMM) can be derived as a special case of PCA fuzzy mixture model. In our experiments, with having the number of mixtures equal, the proposed method requires less training time and less storage as well as shows better speaker identification rate compared to the conventional GMM. Also, the proposed one shows equal or better identification performance than the orthogonal GMM does.

• Steel and Composite Structures
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• 제6권1호
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• pp.33-53
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• 2006

The rotational behaviour of bolted extended end plate beam-to-column connections is evaluated in the context of the component method. The full moment-rotation response is characterized from the force-deformation curve of the individual joint components. The deformability of end plate connections is mostly governed by the bending of the column flange and/or end plate and tension elongation of the bolts. These components form the tension zone of the joint that can be modelled by means of "equivalent T-stubs". A systematic analytical procedure for characterization of the monotonic force-deformation behaviour of individual T-stub connections is proposed. In the framework of the component method, the T-stub is then inserted in the joint spring model to generate the moment-rotation response of the joint. The procedures are validated with the results from an experimental investigation of eight statically loaded extended end plate bolted moment connections carried out at the Delft University of Technology. Because ductility is such an important property in terms of joint performance, particularly in the partial strength joint scenario, special attention is given to this issue.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.12-22
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• 2007

This paper presents to predict the powertrain structure-borne noise which is primary resource of interior noise. As the first step, it is built up a hybrid powertrain model which is based on the real powertrain which is verified with static and dynamic properties. The methods for verifying are modal analysis and running vibration testing which are experimentally implemented. Based on the Hybrid powertrain component model, an initial predictive assembly model is simulated. As the second step, the characteristic transfer functions are measured that are dynamic stiffness of rubber mounts and vibro-acoustic transfer function based on the acoustic reciprocity. Several techniques utilizing special experimental devices have been proposed for this research. Finally, the structure-borne noise by powertrain will be predict and verify with dynamic simulation and experiment.

• KIEE International Transactions on Power Engineering
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• 제12A권1호
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• pp.6-14
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• 2002

In this paper, an EMM(Equivalent Mechanical Model) Is developed to explain the voltage collapse mechanism by reflecting the effects of reactive powers. The proposed EMM exactly represents the voltage instability mechanism described by the system equations. By the use of the EMM model, the voltage collapse mechanism has been illustrated by showing the exactness of the results. The stable region has been investigated with a reactive-power-controlled two-bus system, which shows that special alerts are required when the system operates with leading power factor. It is also discussed a system transform technique to eliminate the resistance component of the Thevenin equivalent impedance for practical applications. Finally, the results adopting the proposed method fur sample systems which were transformed are listed