• Korean Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.201-209
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• 1998

To develop timely an optimal fan, a design system and a new manufacturing process used step by step have to be integrated. A small sized optimal fan for refrigerators, that was the goal on this project, was developed by the following principal processes. All processes are technologically linked in many directions: The existing fan was measured through reverse engineering. The measured data was used for the basic source of 3D design. The performance tests were carried and used as the data for the evaluation of the existing fan. Flow analysis by FANS-3D/sup [1]/ was performed at the given information (pressure drop and flow rate) to find out the configuration of optimal fan design. The flow patterns were investigated to measure the performance of fan through numerical experiment. The grid point data obtained by the above analysis turned into 3D high efficiency fan model by using CATIA. The product was manufactured by RP process (SLS, SLA) and tested the characteristic curves of the developed fan to compare with the existing fan. The modification of fan design were all examined to see any change in performance and checked to find any deficiency in assembling the fan into a duct. After the plastics flow analysis of the injection molding cycle to ensure acceptable quality fan, an optimal mold was processed by using tool-path for the newly designed fan.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.64-73
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• 2012

Pointing stability of high precision observation satellites must satisfy the stringent requirements to perform at a designed level. As even a small vibrational disturbance can result in severe degradation of the optical performance, the effects of inorbit vibrational environment on the performance of optical payload must be predicted and analyzed in the design phase in order to ensure that the requirements imposed on the payload are fully met. In this paper, an integrated framework for the evaluation of the performance of optical payloads is developed. The developed simulation tool comprises of the reaction wheel induced disturbance model, state space model of a structure in modal form and Cassegrain reflector model. The performance degradation of the optical system due to jitter is expressed by using modulation transfer function (MTF) and image simulation. Moreover, vibration isolator model is also added to show the effectiveness of using a vibration isolator for the elimination of the effects of jitter in the acquisition of an image.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.408-417
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• 2021

This paper describes the quality attributes of an integrated simulation software for weapon systems named Advanced distributed simulation environment(AddSIM). AddSIM is developed as a key enabler for Defense Modeling & Simulation(M&S) systems which simulate battlefields and used for battle experiments, analyses, military exercises, training, etc. AddSIM shall provide a standard simulation framework of the next Defense M&S systems. Therefore AddSIM shall satisfy not only functional but also quality requirements such as availability, modifiability, performance, testability, usability, and others. AddSIM consists of operating softwares of hierarchical components including graphical user interface, simulation engines, and support services(natural environment model, math utility, etc.), and separated weapon system models executable on the operating softwares. The relation between software architectures and their quality attributes are summarized from previous works. And the AddSIM architecture and its achievements in the aspect of quality attributes are reviewed.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.6
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• pp.615-631
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• 2012

This study provides an evaluation for capability of Integrated Climate and Air quality Modeling System (ICAMS) on future regional scale climate projection. Temperature and precipitation are compared between ground-level observation data and results of regional models (MM5) for the past 30 years over the Korean peninsula. The ICAMS successfully simulates the local-scale spatial/seasonal variation of the temperature and precipitation. The probability distribution of simulated daily mean and minimum temperature agree well with the observed patterns and trends, although mean temperature shows a little cold bias about $1^{\circ}C$ compared to observations. It seems that a systematic cold bias is mostly due to an underestimation of maximum temperature. In the case of precipitation, the rainfall in winter and light rainfall are remarkably simulated well, but summer precipitation is underestimated in the heavy rainfall phenomena of exceeding 20 mm/day. The ICAMS shows a tendency to overestimate the number of washout days about 7%. Those results of this study indicate that the performance of ICAMS is reasonable regarding to air quality predication over the Korean peninsula.

• Structural Engineering and Mechanics
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• v.7 no.6
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• pp.589-599
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• 1999

This paper presents the development and applications of the software package JIFEX, a new finite element system which can be used for structural analysis and optimum design by the modern computer hardware and software technologies such as MS Windows95/NT and Pentium PC platforms. The complete system of JIFEX is programmed with $C/C^{++}$ language to make full use of advanced facilities of MS Windows95/NT. In the system, the finite element data pre-processing, based on the most popular CAD package AutoCAD (R13, R14), has been implemented, so that the finite element modeling could be integrated with geometric modeling of CAD. The system not only has interactive graphics facility for data post-processing, but also realizes the real-time computing visualization by means of the Dynamic Data Exchange (DDE) technique. Running on the Pentium computers, JIFEX can solve large-scale finite element analysis problems such as the ones with more than 60000 nodes in the finite element model.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.449-452
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• 1998

In this study, the basic image-board and algorithm has been developed to extract a road lane by modeling the driving process. The high speed processing enables an image capture, processing and prompt decision making. In order to high speed processing ASIC like FPGA was designed and integrated in one board system. The algorithm enabling road driving must recognize a straight and bend edge separately. The high speed image processing board using FPGA can be used in real-time decision makeing system for road driving and in the machine vision under bad working environments like a coal mine. And it also can be used in the safety control system in subway and in image input system of CCTV and CATV by designing the board to meet various user's needs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1882-1887
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• 2002

This study is to develop a automatic design program of mechanical elements as the integrated system which can create automatically 3-dimensional solid and surface model using visualLISP. By the applying developed system to CAE system, the following objects are realized. At first, constructing the library of automatic design program for unexperienced design engineer, the 3-dimensional modeling of mechanical elements can be obtained easily. at second, the 3-dimensional model for ratchet wheel design is created by finete element model of CAE system and the optimal design condition of key way.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.366-370
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• 2002

A kinematic ball bar measurement system can analyze the various errors of a machine tool easily and rapidly in a procedure and can measure many types of equipment such as chip mounter, PCB router, precision stage, etc. In this paper, the thermally induced errors are loused among various errors of a chip mounter because it affects the accuracy of the machine very much. Linear regression technique is adapted for the thermal error modeling. While the measurement and calibration of a chip mounter is difficult in general, this developed system is not only easy to apply for it but also improves the accuracy by 4 times or more.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.74-80
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• 2002

As "Nationwide Educational Information System", as one of 11 essential tasks of the electronic government, is to be introduced step by step from March in 2003, the current School Information Management System servers in each school cannot be functioned appropriately any more. Management of school cumulative records will be done by the integrated server of the regional Office of Education. Accordingly, more than 20,000 servers of various kinds available in each school should be put into use in one way or another. So this thesis aims to suggest how to reuse these servers in schools, and how to approach modeling of the 21st-century school in the School Information Management System.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.51-54
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• 2001

For performing Intelligent Transport System, I will implement the vehicle recognition system used image as well as Real time transmission module with TCP/IP. Generally, there are two kinds for vehicle recognition technology. Between two methods, the image-based method has a high dependency on environmental condition. Therefore, in this thesis I will propose vehicle recognition algorithm based on image using improved Gradient Method. Also I propose server-client modeling with TCP/IP, for the purpose of real time transmission of processed data and images. So I made the vehicle recognition and real time transmission system with TCP/IP for verification of proposed algorithm.