• 한국시뮬레이션학회논문지
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• 제10권3호
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• pp.1-14
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• 2001

A hybrid system is defined as a mixture of continuous systems and discrete event systems. This paper first proposes a framework for hybrid systems modeling, called Hybrid Discrete Event System Specification (HDEVS) formalism. It then presents a method for simulators interoperation in which a continuous system simulator and a discrete event simulator are executed together in a cooperative manner. The formalism can specify a hybrid system in a way that a continuos system and a discrete event system are separately modeled by their own specification formalisms with a support of well-defined interface. We call such interface an A/E converter for analog-to- event conversion and an E/A converter for event-to-analog conversion. Simulators interoperation is based on the concept of pre-simulation in which simulation time for a continuous simulator is advanced in accordance with a discrete event simulator.

• 디자인학연구
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• 제14권
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• pp.87-106
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• 1996

전자 기술과 반도체 기술의 발달로 인해서 제품은 다양한 지적인 기능을 갖게 되었다. 그러나 이러한 다양한 기능 때문에 사용자는 제품의 형태만으로 그 제품의 사용에 관한 정보를 얻기가 불가능해졌다. 이런 상황에서 사용자 인터페이스 디자인은 점점 더 중요하게 되었다. 그러나 이 분야의 연구방법은 주로 컴퓨터 프로그램의 사용자 인터페이스 디자인 개발을 위한 것이고, 여러 대안을 개발한 후 이를 평가하는 단계에서 사용될 수 있는 방법이다. 따라서 본 연구는 제품에 적합한 사용자 인터페이스 디자인을 개발하는데 적용될 수 있는 모델 링 기법을 개발하는 것으로 목표로 한다. 먼저 모델 링 기법의 본질을 이해한 후, 여러 가지 모델 링 기법을 고찰하고 각 기법의 장단점을 파악한다. 그리고 이런 장단점을 바탕으로 개발될 모델 링 기법의 목표를 설정한다. 그 목표를 기반으로 제품의 사용자 인터페이스 디자인에 적합한 모델 링 기법을 제안하고, 이를 실제 제품에 적용하여 제안된 모델 링 기법의 적용 방법을 예시하고 그 기법의 효용성과 장단점을 파악한다.

• 한국정보시스템학회지:정보시스템연구
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• 제30권1호
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• pp.45-64
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• 2021

Purpose The traditional topic modeling technique makes it difficult to distinguish the semantic of topics because the key words assigned to each topic would be also assigned to other topics. This problem could become severe when the number of online reviews are small. In this paper, the extended model of topic modeling technique that can be used for analyzing a small amount of online reviews is proposed. Design/methodology/approach The extended model of being proposed in this paper is a form that combines the traditional topic modeling technique and the Word2Vec technique. The extended model only allocates main words to the extracted topics, but also generates discriminatory words between topics. In particular, Word2vec technique is applied in the process of extracting related words semantically for each discriminatory word. In the extended model, main words and discriminatory words with similar words semantically are used in the process of semantic classification and naming of extracted topics, so that the semantic classification and naming of topics can be more clearly performed. For case study, online reviews related with Udo in Tripadvisor web site were analyzed by applying the traditional topic modeling and the proposed extension model. In the process of semantic classification and naming of the extracted topics, the traditional topic modeling technique and the extended model were compared. Findings Since the extended model is a concept that utilizes additional information in the existing topic modeling information, it can be confirmed that it is more effective than the existing topic modeling in semantic division between topics and the process of assigning topic names.

• International Journal of Computer Science & Network Security
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• 제23권5호
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• pp.21-32
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• 2023

The design of complex man-made systems mostly involves a conceptual modeling phase; therefore, it is important to ensure an appropriate analysis method for these models. A key concept for such analysis is the development of a diagramming technique (e.g., UML) because diagrams can describe entities and processes and emphasize important aspects of the systems being described. The analysis also includes an examination of ontological concepts such as states and events, which are used as a basis for the modeling process. Studying fundamental concepts allows us to understand more deeply the relationship between these concepts and modeling frameworks. In this paper, we critically analyze the classic definition of a state utilizing the Thinging machine (TM) model. States in state machine diagrams are considered the appropriate basis for modeling system behavioral aspects. Despite its wide application in hardware design, the integration of a state machine model into a software system's modeling requirements increased the difficulty of graphical representation (e.g., integration between structural and behavioral diagrams). To understand such a problem, in this paper, we project (create an equivalent representation of) states in TM machines. As a case study, we re-modeled a state machine of an assembly line system in a TM. Additionally, we added possible triggers (transitions) of the given states to the TM representation. The outcome is a complicated picture of assembly line behavior. Therefore, as an alternative solution, we re-modeled the assembly line based solely on the TM. This new model presents a clear contrast between state-based modeling of assembly line behavior and the TM approach. The TM modeling seems more systematic than its counterpart, the state machine, and its notions are well defined. In a TM, states are just compound events. A model of a more complex system than the one in the assembly line has strengthened such a conclusion.

• 보건교육건강증진학회지
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• 제23권2호
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• pp.91-107
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• 2006

Objectives: The school adjustment problems of the adolescence groups become more aggravated and are on the increase. The objective of this study is to identify the causal relationship of intra-family conflicts, self-concept and school adjustment as health protection behavior. Methods: The study setting is the adolescence groups. Data were collected by self-administered questionnaires from the middle and high school students in Seoul. The study sample consisted of 268 students. Structural Equation Modeling(SEM) analysis was conducted to find the causal relationship of intra-family conflicts, self-concept and school adjustment. Results: This study shows that firstly, the total effects of intra-family conflicts have a negative effect on self-concept(path coefficients=-0.080) and school adjustment(path coefficients=-0.107). And the self-concept factor as an intervening variable are affecting positively on school adjustment(path coefficients=0.411). Secondly, the economic conflicts, personaliy conflicts and social activity conflicts of father and mother among various family conflicts are more highly affecting on self-concept and school adjustment(p<0.01) Conclusions: These results imply that first, communication between parents and students is essential to solve the problems of school adjustment. Especially economic conflicts should be solved to improve the self-concept and school adjustment. second, a variety of programs are available for schools to employ in an effort to provide interventions for students who demonstrate school adjustment. Finally, it is necessary for family, school and all the society members to comprehensively cooperate to solve family conflicts and school adjustment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.540-545
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• 2001

In case of small motors, coil bundle occupies a large portion of stator in view of mass and volume as well as dynamics. It is observed through modal test on the stator of an IPM BLDC (interior permanent magnet brushless direct current) motor that coil bundle wound on the stator core causes the first and second natural frequencies to decrease by about 20-30% compared with those of bare stator. Especially the third natural frequency is newly observed below 3 KHz, which is not observed on the bare stator. It is found that at the third mode the end-coil and the core vibrate out of phase in radial direction. In this paper, the stator is dynamically modeled in terms of the core and the coil bundle consisting of the end-coil and the slot coil based on the above observations for the prediction of dynamic properties. The core can easily be modeled using finite element method with its actual material properties and geometric shape. The concept of equivalent bending stiffness is used for modeling of the end-coil so that predictions may match with the measured natural frequencies for the end-coil cut out of the stator. Although the same concept can be applied to the slot coil, separation of the slot coil from the stator is impractical. Therefore, equivalent bending stiffness of the slot coil is determined through iterative comparisons with the measurements of natural frequencies of the stator with the slot coil in it.

• Journal of Welding and Joining
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• 제26권6호
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• pp.74-80
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• 2008

A finite element modeling approach has been described for the simulation and analysis of the micron-scaled solid particle impact behavior in kinetic spraying process, using an explicit code (ABAQUS 6.7-2). High-strain-rate plastic deformation and interface bonding features of the copper, nickel, aluminum, and titanium were investigated via FEM in conjunction with the Johnson-Cook plasticity model. Different aspects of adiabatic shear instabilities of the materials were characterized as a concept of thermal boost-up zone (TBZ), and also discussed based upon energy balance concept with respect to relative recovery energy (RRE) for the purpose of optimizing the bonding process.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2828-2839
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• 2022

This study developed a safety assessment tool for geological disposal systems called APro, a systemically integrated modeling system based on modularizing and coupling the processes which need to be considered in a geological disposal system. Thermal, hydraulic, chemical, canister failure, radionuclide release and transport processes were considered in the current version of APro. Each of the unit processes in APro consists of a single Default Module, and several Alternative Modules which can increase the flexibility of the model. As an initial stage of developing the modularization concept and modeling interface, the Default Modules of each unit process were described, with one Alternative Module of chemical process. The computation part of APro is mainly a MATLAB workspace controlling COMSOL and PHREEQC, which are coupled by an operator splitting scheme. The APro model domain is a stylized geological disposal system employing the Swedish disposal concept (KBS-3 type), but the repository layout can be freely adjusted. In order to show the applicability of APro to the total system performance assessment of geological disposal system, some sample simulations were conducted. From the results, it was confirmed that coupling of the thermal and hydraulic processes and coupling of the canister failure and the radionuclide release processes were well reflected in APro. In addition, the technical connectivity between COMSOL and PHREEQC was also confirmed.

• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.390-397
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• 2022

Affordance is a kind of mental physiology, used by psychologist Donald A. Norman as a design idea, defined as "the property that something can directly and essentially provide something to a person or animal". This idea of returning to the essence and providing properties intuitively has a new guiding effect on product design. The purpose of this thesis is to take the theory of affordance as the basis of design concept, and redesign the shape of desktop lamps in small home appliances, so as to optimize the product shape. A product styling design method based on the concept of affordance is established through four major classifications of affordance, and a styling design scheme is completed using a tabletop luminaire in small home appliances as an example, and then a product styling design evaluation system is used to evaluate the new tabletop luminaire styling design scheme and the existing styling, and the evaluation results are analyzed. Finally, it is concluded that a new product styling design method based on affordance is constructed, and the feasibility and effectiveness of this method are verified, which provides ideas and theoretical basis for product styling design.

• 한국군사과학기술학회지
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• 제25권5호
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• pp.530-538
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• 2022

Recently, the R&D of weapon systems has been strengthened in terms of economic cost management throughout the entire life cycle from performance. This study proposes the method for setting the optimal maintenance concept based on RAM-C in weapon system acquisition stage by calculating the operation & maintenance cost as well as reliability, availability, and maintainability. First, we design a simulation model for analysis of weapon system logistic supportability. In addition, information such as weapon system Part Breakdown Structure, operation & maintenance system, cost, and etc for simulation analysis, is applied. Based on the obtained simulation results, the optimal plan is selected among alternatives designed with various maintenance concepts through normalization and weight setting. It is expected to be of technical help in the application of RAM-C in the weapon system acquisition stage.