• Journal of Applied Reliability
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• v.17 no.4
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• pp.296-304
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• 2017

Purpose: Recent weapon systems in defense have increased the complexity and importance of software when developing multifunctional equipment. In this study, we analyze the accuracy of the proposed software reliability model when applied to weapon systems. Methods: Determine the similarity between software reliability analysis results (prediction/estimation) utilizing data from developing weapon systems and system failures data during operation of weapon systems. Results: In case of a software reliability prediction model, the predicted failure rate was higher than the actual failure rate, and the estimation model was consistent with actual failure history data. Conclusion: The software prediction model needs to adjust the variables that are appropriate for the domestic weapon system environment. As the reliability of software is increasingly important in the defense industry, continuous efforts are needed to ensure accurate reliability analysis in the development of weapon systems.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.2
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• pp.77-82
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• 2023

The structural analysis module is an essential part of any integrated structural system. Diverse integrated systems today require, from the analysis module, efficient real-time responses to real-time input such as earthquake signals, extreme weather-related forces, and man-made accidents. An integrated system may also be for the entire life span of a civil structure conceived during the initial conception, developed throughout various design stages, effectively used in construction, and utilized during usage and maintenance. All these integrated systems' essential part is the structural analysis module, which must be automated and computationally efficient so that responses may be almost immediate. The finite element method is often used for structural analysis, and for automation, many effective finite element meshes must be automatically generated for a given analysis. A computationally efficient finite element mesh generation scheme based on the r-h method of mesh refinement using strain deviations from the values at the Gauss points as error estimates from the previous mesh is described. Shape factors are used to sort out overly distorted elements. A standard cantilever beam analyzed by four-node plane stress elements is used as an example to show the effectiveness of the automated algorithm for a time-domain dynamic analysis. Although recent developments in computer hardware and software have made many new applications in integrated structural systems possible, structural analysis still needs to be executed efficiently in real-time. The algorithm applies to diverse integrated systems, including nonlinear analyses and general dynamic problems in earthquake engineering.

• Current Optics and Photonics
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• v.3 no.5
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• pp.429-437
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• 2019

Temperature adaptability is an important metric for evaluating the performance of an optical system. The temperature characteristics of the optical system are closely related to the material and shape of its lens. In this paper, we establish a mathematical model relating the temperature characteristics to the shape and material of the lens. Then a novel assembly structure that can solve the lens constraint and positioning problem is proposed. From those basics, the correctness of the theoretical model and the effectiveness of the assembly structure are verified through simulated analysis of the imaging quality of the optical system, whose operating temperature range is $-60{\sim}100^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.395-402
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• 2005

Recently Multidisciplinary Design Optimization Based on Independent Subspaces (MDOIS), an MDO (multidisciplinary design optimization) algorithm, has been proposed. In this research, an MDO problem is defined for design of a belt integrated seat considering crashworthiness, and MDOIS is applied to solve the problem. The crash model consists of an airbag, a belt integrated seat (BIS), an energy absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural nonlin- ear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified and is addressed in the system analysis step in MDOIS. Interdisciplinary variables are belt load and stiffness of the seat, which are determined in system analysis step. The belt load is passed to the structural analysis subspace and stiffness of the seat back frame to the occupant analysis subspace. Determined design vari- ables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and Head Injury Crite- rion (HIC) of an occupant are reduced with specified constraints satisfied at the same time. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formu - lated to solve the system analysis. The results from MDOIS are discussed.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.1
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• pp.14-19
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• 2005

High temperature vacuum furnaces or high standard electric furnaces demand high technology level and high production cost. Therefore, an iterative design process and the optimization approach under integrated computing environment are required to reduce the development risk. Moreover, it also required to develop an integrated design software that can manage the centralized database system between factory and design department, and the automated furnace design and analysis. The developed software is dedicated to the development of the vacuum (electric) furnaces. Based on the distribute middleware system, the GUI module, the CAD module, the thermal analysis module and the optimization module are integrated. For the DBMS, Microsoft Access is employed, the GUI is developed using Visual Basic language, and AutoCAD is utilized for the configuration design. By investigating the analysis code interface, the analysis and optimization process, and the data communication method, the overall system architecture, the method to integrate the optimizer and ana lysis codes, and the method to manage the data flow are proposed and verified through the optimal furnace design.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.1
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• pp.38-43
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• 2022

As the use of unmanned aerial vehicles increases, in order to expand the operability of the unmanned aerial vehicle, it is essential to develop an unmanned aerial vehicle traffic management system, and to establish the system, it is necessary to analyze the integrated navigation performance of the unmanned aerial vehicle to be operated. Integrated navigation performance is affected by various factors such as the type of unmanned aerial vehicle, flight environment, and guidance law algorithm. In addition, since a large amount of flight data is required to obtain high-reliability analysis results, efficient and consistent flight scenarios are required. In this paper, a flight scenario that satisfies the requirements for integrated navigation performance analysis of rotary and fixed-wing unmanned aerial vehicles was designed and verified through flight experiments.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.120-127
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• 1993

This paper is concerned with the integrated computer program system aiming at efficiently performing the structural analysis and design. The developed computer program system is introduced and applied to a simple two-dimensional structure to show the general concept of the integrated system. Some design modifications and re-analyses are illustrated including local mesh refinement, These show the efficiency in doing design modification and analysis.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1042-1045
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• 1998

The main purpose of HITES(Highly Integrate Total Energy System) is to build and develop an integrated energy system for power system operational planning and analysis which consists of load forecast, economic generation schedule, stability analysis and relational database system. The integrated energy system can be utilized to supply a stable electric power and operate KEPCO power system facilities economically. This system will be put into operation in 1999. This paper describes the main feature of the HITES, system main functions, numerical methods adopted this system, and network configuration.

• Journal of Korean Library and Information Science Society
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• v.48 no.2
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• pp.373-403
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• 2017

The purpose of this study is to establish the classification principle of archives for the May 18th democratic uprising in terms of preservation and utilization of it and to develop an integrated classification system for it. For this purpose, it was carried out by the previous research on the classification of records and institutional case analysis. Also, we developed an integrated provenance-based classification system based on the practical analysis on the data held in 3 representative institutions in Gwangju. This classification system was proposed by facets of 'provenance-material-period-media-subject' type. We also proposed the collection-based integrated classification system that reflects on the expansion of archivists' role and the trend of times.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.1029-1037
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• 2004

High-speed/precision servomechanisms have been widely used in the manufacturing and semiconductor industries. In order to ensure the required high-speed and high-precision specifications in servomechanisms, an integrated design methodology is required, where the interactions between mechanical and electrical subsystems will have to be considered simultaneously. For the first step of the integrated design process, it is necessary to obtain not only strict mathematical models of separate subsystems but also formulation of an integrated design problem. A two-degree-of-freedom controller described in the discrete-time domain is considered as an electrical subsystem in this paper. An accurate identification process of the mechanical subsystem is conducted to verify the obtained mathematical model. Mechanical and electrical constraints render the integrated design problem accurate. Analysis of the system performance according to design and operating parameters is conducted for better understanding of the dynamic behavior and interactions of the servomechanism. Experiments are performed to verify the validity of the integrated design problem in the x-Y positioning system.