• International Journal of Automotive Technology
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• v.8 no.3
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• pp.289-298
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• 2007

A nonlinear dynamic simulation model from cranking to idle speed is developed to optimize the cold start process of a diesel engine. Physically-based first order nonlinear differential equations and some algebraic equations describing engine dynamics and starter motor dynamics are used to model the performance of cold starting process which is very complex and involves many components including the cold start aiding method. These equations are solved using numerical schemes to describe the starting process of a diesel engine and to study the effects of cold starting parameters. The validity of this model is examined by a cold start test at $-20^{\circ}C$. Using the developed model the effects of the important starting variables on the cold starting processes were investigated. This model can be served as a tool for designing computer aided control systems that improve cold start performance.

• Journal of Information Technology Services
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• v.8 no.2
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• pp.173-187
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• 2009

CASE tools are complex software products offering many different features. Systems professionals have evaluated various CASE products from a feature and attribute basis. Each product has a different mix of strengths and weaknesses as perceived by the end user. Specific CASE tools support different steps of the applications development process as well as varying methodologies. In this paper we develop a method for evaluating CASE tools. The model has an analytic hierarchy process for evaluating CASE tools in terms of functionality, management efficiency, and support ability of provider, and a data envelopment analysis for overall evaluation considering cost and AHP results. We applied the developed model to a real world case study.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1494-1498
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• 2008

This paper shows a case study on the design of the schema of the information DB of the City-Train Standardization project. The process used in this case is : Database development, Schema design, and cross referencing of the data with the work process items. The DB and the schema was implemented using computer aided systems engineering tool Cradle■. We expect that the user can find the data and the related information very easily, quickly without omission.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.174-179
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• 2004

To maintain design-knowledge database and manage configuration for requirement of performance test and safety standard of High Speed Railroad, It is established that managment system of performance test and safety standard and then constructed that design-knowledge database and documented a performance test and safety specification for supporting performance test and safety system using computer-aided tool.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.156-165
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• 2000

This paper describes modeling and simulation of automotive forward collision warning and avoidance system using CASE(Computer-Aided Systems Engineering) tool. The system is composed or many sensors, a controller, warning devices, brakes and etc. The system was modeled by one activity chart, fourteen state charts and one module chart. Rear-end collision scenarios was generated by Simulink and used to support Stalemate model. The resulting model was used to evaluate the correctness of function and behavior of the system. A simulator for the system has been designed and used to validate the model under realistic operating conditions in the laboratory. To model and simulate the system's functionality and behavior brings clarity to system design early in the system development.

• Journal of the Korea Safety Management & Science
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• v.9 no.6
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• pp.39-46
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• 2007

In this paper we discuss the problems related with the existing electrical safety system that is influenced by all the socio-technical factors including the electrical safety law, government organizations, and their practicing rules and regulations. Sometimes intangible practices also affect the safety issues. It is our intention to incorporate all those factors effectively and systematically in improving the electrical safety system. Since, the problem in nature is so complex, an approach based on the systems engineering (SE) method could be a good candidate. Specifically, as a first step of the SE process we performed the requirements analysis of all the factors mentioned above and some recommendations from the experts in the field. In the work environment utilizing a computer-aided SE tool, the requirements are verified and managed efficiently although the data base is complicated in general in tracking the changes. Next, by analyzing the verified requirements, a functional architecture is developed to achieve an improved electrical safety system. We also did the reverse engineering of the existing electrical safety system to explore potential problems there. The result can also help improve the existing one. Overall, a systematic approach to constructing electrical safety system based on SE is proposed for the first time in this paper. Note that the method described here can be adopted in the study of other safety systems.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.43-52
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• 2014

In weapon systems development, live fire tests have been frequently adopted to evaluate the performance of the systems under development. Therefore, it is necessary to ensure safety in the test ranges where the live fire tests can cause serious hazards. During the tests, a special care must be taken to protect the test and evaluation (T&E) personnel and also test assets from potential danger and hazards. Thus, the development and management of the range safety process is quite important in the tests of guided missiles and artillery considering the explosive power of the destruction. Note also that with a newly evolving era of weapon systems such as laser, EMP and non-lethal weapons, the test procedure for such systems is very complex. Therefore, keeping the safety level in the test ranges is getting more difficult due to the increased unpredictability for unknown hazards. The objective of this paper is to study on how to enhance the safety in the test ranges. To do so, an approach is proposed based on model-based systems engineering (MBSE). Specifically, a functional architecture is derived utilizing the MBSE method for the design of the range safety process under the condition that the derived architecture must satisfy both the complex test situation and the safety requirements. The architecture developed in the paper has also been investigated by simulation using a computer-aided systems engineering tool. The systematic application of this study in weapon live tests is expected to reduce unexpected hazards and test design time. Our approach is intended to be a trial to get closer to the recent theme in T&E community, "Testing at the speed of stakeholder's need and rapid requirement for rapid acquisition."

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.135-143
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• 2006

This paper describes a requirement architecture modeling for the front end of KT-1 export version requirement definition processes to construct SDS(system development specification). The requirement definition process is a highly conceptual process that is difficult to carry out. This paper focuses on how to perform the KT-1 export version requirements definition process including the integration of process, methods and tools for the front-end activity of requirements definition process. This requirement model is structured in four segments, including requirement layering, requirement categorization, life cycle stakeholder and requirement definition process using Computer-Aided Systems Engineering tool(CORE).

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.389-405
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• 2013

A facility layout design (FLD) problem can be generally introduced as assignment of facilities (departments) to a site such that a set of criteria are satisfied or some objectives are minimized (maximized). Hence, it can be considered as a multi-criteria problem due to the presence of qualitative criteria such as maintenance or flexibility and quantitative criteria such as the total cost of handling material. The VIKOR method was developed to solve multiple criteria decision making problems with conflicting and non-commensurable (different units) criteria, assuming that compromising is acceptable for conflict resolution, the decision maker wants a solution that is the closest to the ideal, and the alternatives are evaluated according to all established criteria. This paper proposes a hierarchical analytic hierarchy process (AHP) and VIKOR approach to solve the FLD problem. A computer-aided layout-planning tool is adopted to generate the facility layout problems, as well as their quantitative data. The qualitative performance measures are weighted by AHP. VIKOR is then used to solve the FLD problem. Finally, the proposed integrated procedure is applied to three real-time examples.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.551-556
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• 2009

3-D CAD (Computer Aided Design) system is an indispensable tool for manufacturing. A lot of engineers have studied for the methods to generate a curved surface on an N-sided shape, which is the basic technology of 3-D CAD systems. This surface generation, however, has three problems on the case of long and narrow shapes: the resultant surface is distorted, the surface is not continuous to adjacent surfaces, or additional user inputs are required to generate the surface. Conventional methods have not yet solved these problems at the same time. In this paper, we propose the method to generate internal curves that divide a long and narrow shape into regular N-sided sections so as to divide the shape into an N-sided section and four-sided ones. Our method controls the shape of internal curves by dividing an N-sided long and narrow shape into an N-sided section and four-sided ones, and solves distortion of the generated curved surface. In addition, each of the generated sections is interpolated with G1-continuous surfaces. This process does not require any user's further input. Therefore, the three problems mentioned above will be solved at the same time.