• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.55-63
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• 2003

An attitude control system using reaction thrusters for the upper stage of a launch vehicle is considered. The thruster configuration (position and direction) determines control system response, fuel consumption, effective torque and system fault tolerance. We propose a procedure for finding the optimal thruster configuration with desired control effectiveness over the range of selected torque commands. An optimization technique called Particle Swarm Optimization is used for the numerical experiments. The validity of the solution is checked through computer simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2217-2223
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• 2012

As smartphone users are over 20 million, companies, which offer cloud computing services, try to support various mobile devices. If so, users can use the same cloud computing service using mobile devices, as sharing document. When user share the work, there are problem in configuration management, data confidentiality and integrity. In this paper, we propose a method that cloud computing users share document efficiently, edit encrypted docuements, and manage configuration based on homomorphic encryption, which integrity is verifiable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1404-1415
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• 2016

Because of the properties of software such as invisibility, complexity, and changeability, software configuration management (SCM) for software artifacts generated during software life-cycle has been used for guarantee of the quality of the software. However, the existing SCM system has only focused on code artifacts and software development document artifacts such as Software Requirements Specification (SRS), Software Design Description (SDD), and Software Test Description (STD). Moreover, software research-oriented project comes out late the code artifacts and the software development document artifacts. Therefore, there is a need for trace and management of software research document artifacts composed of highly abstracted non-functional requirements like 'the purpose of the project', 'the objectives', and 'the progress' before generation of the code artifacts and the software development document artifacts for a long time. Nevertheless, the existing SCM system cannot trace and manage them. In this paper, we propose content-based configuration management system comprised of the relevance link generation phase and content-based testing phase to trace and manage them. The preliminary application results show applicability and feasibility of the proposed system.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.19-26
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• 2012

The requirement for the aerodynamic hub drag, allocated from the system requirement of development of a bearingless rotor hub, was analyzed and embodied to be substantiated by the methodology assigned from the requirement. Drag prediction for the initial hub configuration was carried out by hand calculation using aerodynamic drag coefficients and the design change about the sectional shape of torque tube was suggested to satisfy the requirement. Finally, drag prediction was performed for the changed hub configuration by using unstructured overset mesh technique and parallel computation and the calculated result satisfied the requirement of the aerodynamic hub drag. It was found that the drag of final hub configuration was also within the range of drag inferred from the trendline of developed helicopter.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.472-482
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• 2013

This paper proposes a wireless LAN topology configuration method for enhancing indoor location-awareness and improving network performance simultaneously. We first develop four objective functions that yield objective goals significant to the optimal design of a wireless LAN topology in terms of location-awareness accuracy and network performance factors. Then, we develop metaheuristic algorithms such as simulated annealing, tabu search, and genetic algorithm that examine the proposed objective functions and generate a near-optimal solution for a given objective function. Finally, four objective functions and metaheuristic algorithms developed in this paper are exploited to evaluate and measure the performance of the proposed wireless LAN topology configuration method.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.341-358
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• 2015

Purpose: This paper presents graphic methods and desirability function approach to determine best vibration reducing configuration for Surion helicopter. Many flight tests were executed and nine vibration levels in cockpit, cabin, and engine room were measured in each test and analyzed to find optimal configuration. Methods: Graphic analysis methods such as matrix, scatter, and box plots are used to identify better vibration-reducing flight test conditions. As an integrated measure of the performance of 9 vibration levels desirability function approach is adopted. Results: Three vibration reducing configurations are found to be proper and one configuration is recommended. Conclusion: It is expected to be helpful to adopt graphic and desirability function methods presented in this paper in developing new products or systems like helicopters. For efficient and effective flight testing of helicopters, it will be necessary to have consistently homogeneous environment for flight testing and applying design of experiments techniques and analyzing test data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.9-15
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• 2005

This paper describes the test carried out on an experimental study of fuselage drag and stability characteristics of a helicopter configuration and the test techniques developed for the testing and the lessons learned in the Agency for Defense Development Low Speed Wind Tunnel(ADD-LSWT). The main objective of this test is to determine the drag and stability characteristics of helicopter configurations according to the various configuration changes. The fuselage model with a highly modular structure is a representation of 1:8 scale of the external contour of the conceptual design helicopter configuration with rotating main rotor hub including blade stubs capable of rotating up to 500 rpm. The test results are compared with the available similar data and fair to good agreement is obtained.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.503-505
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• 2008

The purpose of the current study is to examine the aerodynamic characteristics of two hypersonic vehicles in near space. One is derived from waverider shape, and the other from liftbody. The objective of this study are threefold. The first is to creat an computational database for hypersonic vehicle configurations. The second is to examine the effects of individual vehicle components on hypersonic configurations and to determine the differences in aerodynamic characteristics that result from integrating all vehicle components. The third objective is to evaluate the controllability of each of the fully integrated vehicles and the effectiveness of the control surface design. These objectives were accomplished using DSMC solutions and aerodynamic code developed in Northwestern Polytechnical University. The results are analyzed also in three sections. First, the results of the waverider shape and liftbody shape without integrated vehicle components are presented. Second, the results of adding aircraft components to the waverider shape and liftbody shape are presented. Finally, the aerodynamic characteristics of the fully integrated waverider-derived configuration and liftbody-derived configuration are examined and compared with those of the pure waverider shape and liftbody shape. Comparation between fully integrated waverider-derived configuration and liftbody-derived configuration are also presented in this paper.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.8
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• pp.57-64
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• 2019

This study attempts to analyse the effects of high-rise living on suicide rates. All the apartments in the City A and every suicide were examined in detail. Research methods are as follows. First, a database including tenure type and number of residents in all apartment complexes was created. Second, apartments were categorized into two income groups of private apartments and social housing, and spatial configuration characteristics of a typical apartment were analysed. Third, differences in suicide rates were analysed for lower and upper levels in both apartment categories. Finally, the relationship between high and lower levels of apartments with their spatial configuration characteristics and suicide rates was compared. The analysis shows significant differences between lower and upper floors living residents' suicide rates. It can be stated that the low-income residents are more sensitive to living in high-rise environment. Also, it suggests the need to improve the high-rise living environment of vulnerable social groups. In addition, spatial integration decrease in upper floors of high-rise buildings, and it can be interpreted that spatial configuration may affect residents' pathological disorders or even suicidal behaviors.

• International Journal of Advanced Culture Technology
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• v.11 no.3
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• pp.172-181
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• 2023

Dunhuang murals are one of the most outstanding achievements in the art of traditional grotto painting in China, and are known as a "Wall Museum". As a representative of the heyday of Dunhuang murals, an in-depth exploration of Dunhuang murals from the perspective of color will help researchers understand the laws and connotations of color in Dunhuang murals during the Tang Dynasty and fully grasp the art of Dunhuang murals. The color system of the traditional Chinese "Five colors" concept expresses the cultural attributes and emotions of the Chinese people and has distinctive national characteristics. This thesis provides a theoretical grasp of the traditional Chinese "Five colors" view of color system, the Dunhuang murals of the Tang Dynasty, and the color configuration of the color composition principles, and uses the modern design principles of color composition to conduct an in-depth analysis of the configuration of the Dunhuang murals' use of color. Explore the unique characteristics of Tang Dynasty Dunhuang murals, and help modern designers master richer color application techniques by learning from and studying the harmonious patterns of Dunhuang murals to provide a new path for the dissemination of excellent Chinese traditional culture.