• Journal of Aerospace System Engineering
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• v.12 no.4
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• pp.64-74
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• 2018

Small high-resolution Earth observation satellites require precise optical alignment at the submicron level. However, misalignments can occur due to the influence of external factors during the launch and operation despite the sufficient alignment processes that take place before the launch. Thus, satellites need to realign their optical elements in orbit in what is known as a refocusing process to compensate for any misalignments. Refocusing algorithms developed for satellites have only considered de-space, which is the most sensitive factor with respect to image quality. However, the existing algorithms can cause correction error when inner and external forces generate tilt amount in an optical system. The present work suggests an improved online refocusing algorithm by considering the tilting effect for application in the case of a de-spaced and tilted optical system. In addition, the algorithm is considered to be efficient in terms of time and cost because it is designed to be used as an online method that does not require ground communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.615-625
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• 2014

Ministry of National Defense, MND, established a "Master Plan of Military Facility" in 2010 based on the defense reform to prepare for future war. It was a plan for consolidating small military facilities into battalion units, reflecting on and preparing for the needs of various changes in defense environment as well as balanced growth of ROK Army, Navy, and Air Force. However, to move forward with "Military Facility Master Plan," current design criteria for military facilities need to be revised to be enacted due to numerous calculation errors in facility footprints because of the absence of a sound facility criteria. Because the future war environment will be changed from Platform basis to Network Centric Warfare basis, Command & Control capability of C4I systems is getting more important. Therefore, Successful mission accomplishment can be secured by convergence of facility and military Information Technology(IT). So, MND should quickly prepare for the operational guidance, design criteria and policy that are suitable for Network Centric Warfare accomplishment, and implement infrastructure of IT and installation of C2 facility in conjunction with consolidation movement of military facilities. In this paper, we propose the defense I3A framework in order to solve this problem.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.9
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• pp.794-806
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• 2017

It is essential to protect the national space assets and space environment safely as a space development country from the continuously increasing space debris. And Active Debris Removal(ADR) is the most active way to solve this problem. In this paper, we studied the Artificial Neural Network(ANN) for a stable recognition model of vision-based space debris tracking system. We obtained the simulated image of the space environment by the KARICAT which is the ground-based space debris clearing satellite testbed developed by the Korea Aerospace Research Institute, and created the vector which encodes structure and color-based features of each object after image segmentation by depth discontinuity. The Feature Vector consists of 3D surface area, principle vector of point cloud, 2D shape and color information. We designed artificial neural network model based on the separated Feature Vector. In order to improve the performance of the artificial neural network, the model is divided according to the categories of the input feature vectors, and the ensemble technique is applied to each model. As a result, we confirmed the performance improvement of recognition model by ensemble technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.185-196
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• 1997

By considering the definition and application of resolution as well as the concept and theory of SAR, the essential contents of the SAR design and analysis are described. This paper is to compare and analyze the resolution performance capability of three techniques for achieving azimuth resolution such as the real aperture, the unfocused and the focused techniques, through the simulation. Simulation is performed to make the restricted conditions for the unfocused technique that can be implemented by the less commputing load of signal processingand the lower cost. Through the mission analysis, the use of SAR image can be applied for estimation of whole situation at the regional area in the field of military demands for tactical purpose as well as civilian demands for the damage of disaster. RPV and sall or medium aircraft are selected to carry the SAR for these purposes and the proper resolution turns ou 5~15 m. The trade-off study of variables through the simulations results in the proper conditions such that range is less 3, 000 m, Wavelength is 1~10 m, and the raw signals and results processed by three techniques for two point targets are exhibited undr such conditions. Therefore, at some points, the result of this paper si proposed for useful applications of unforcused technique in the restricted conditions except the identification of the small target at a long range re- quired for high resolution.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.12
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• pp.1013-1019
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• 2014

Solid-liquid Phase Change Material(PCM) as a thermal control hardware for the electro-optical payload of low earth orbit satellite is numerically studied which can be substituted with Thermal Buffer Mass(TBM). The electro-optical module in LEO satellite is periodically work and high heat is dissipated during the imaging period, however, the design temperature range is very tight and sensitive. In order to handle this problem TBM is added and as a result the time constant of the module temperature increases. TBM is made of Al6010 and its mass directly affects the system design. To save the mass PCM is suggested in this study. The latent heat of melting or solidification is very high and small amount of PCM can play a role instead of TBM. The result shows that only 12% of TBM mass is enough to control the module temperature using PCM.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.395-404
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• 2005

There have been large concerns about survivability defined as the capability of a system to perform a mission-critical role, in a timely manner, in the presence of attacks, failures. In particular, One of the most important core technologies required for the design of the ITS(Intrusion Tolerance System) that performs continuously minimal essential services even when the computer system is partially compromised because of intrusions is the survivability one of In included the dependability analysis of a reliability and availability etc. quantitative dependability analysis of the In. In this Paper, we applied self-healing mechanism utilizing two factors of self-healing mechanism (fault model and system response), the core technology of autonomic computing to secure the protection power of the ITS and consisted of a state transition diagram of the ITS composed of a primary server and a backup server. We also defined the survivability, availability, and downtime cost of the ITS, and then performed studies on simulation experiments and two cases of vulnerability attack. Simulation results show that intrusion tolerance capability at the initial state is more important than coping capability at the attack state in terms of the dependability enhancement.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.1-11
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• 2015

The needs for ecological engineering, which can design ecosystems that integrate human society and their natural environment for the benefit of both, has increased. The Korean Society of Ecology and Infrastructure Engineering (KSEIE) was established for this purpose and has contributed to the research and development of theories and technologies in related fields. However, the current state of educational services and contents of ecological engineering is still needed to be standardized and systematized. In this paper, we outlined the trends of ecological engineering education at international and domestic levels and proposed a sample services and curriculum, brought from the discussions and suggestions made during the forum, Founding the Education for Ecological Engineering, held by the KSEIE. Education of ecological engineering can nurture people who can design and manage ecosystems for the benefits of human and natural society and can restore ecosystems disturbed artificially. The services and curriculum have to meet and cover the challenges facing the future of ecological engineering; a. the ethical interpretation of the balance between human and nature, b. developing and strengthening its relationship with other scientific disciplines and societies - business, policy, education, and practitioners, c. identify and fuse the key ecological engineering principles into other discipline. We proposed a three layers curriculum system, basic (mathematics, physics, chemistry, biology, etc.), core (ecology, hydrology, engineering, etc.), and advanced subjects. The first two can belong to an undergraduate program and the last two can be put into graduate program. The selection of subjects is according to the purpose and needs of the major.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.679-691
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• 2002

Volume visualization is an important subarea of scientific visualization, and is concerned with techniques that are effectively used in generating meaningful and visual information from abstract and complex volume datasets, defined in three- or higher-dimensional space. It has been increasingly important in various fields including meteorology, medical science, and computational fluid dynamics, and so on. On the other hand, virtual reality is a research field focusing on various techniques that aid gaining experiences in virtual worlds with visual, auditory and tactile senses. In this paper, we have developed a visualization system for CAVE, an immersive 3D virtual environment system, which generates stereoscopic images from huge human volume datasets in real-time using an improved volume visualization technique. In order to complement the 3D texture-mapping based volume rendering methods, that easily slow down as data sizes increase, our system utilizes an image-based rendering technique to guarantee real-time performance. The system has been designed to offer a variety of user interface functionality for effective visualization. In this article, we present detailed description on our real-time stereoscopic visualization system, and show how the Visible Korean Human dataset is effectively visualized on CAVE.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.218-224
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• 2012

Recently, as the needs of developing the micro autonomous underwater vehicle (AUV) are increasing, the acquisition of the elementary technology is urgent. While they mostly utilizes information of the forward looking sonar (FLS) in conventional studies of the local path control as an elementary technology, it is desirable to use the obstacle avoidance sonar (OAS) because the size of the FLS is not suitable for the micro AUV. In brief, the local path control system based on the OAS for the micro AUV operates with the following problems: the OAS offers low bearing resolution and local range information, it requires the system that has reduced power consumption to extend the mission execution time, and it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent local path control algorithm based on the beam modeling of OAS with the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance and analyze the characteristic of the proposed algorithm, the course control of the underwater flight vehicle (UFV) is performed in the horizontal plane. Simulation results show that the feasibility of real application and the necessity of additional work in the proposed algorithm.

• Journal of Korean Home Economics Education Association
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• v.19 no.4
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• pp.137-151
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• 2007

The characteristics of Hyeonmoyangcheo-ism (wise mother, good wife) in the 1950s, which were observed through the girls' school curriculums and homekeeping textbooks, were arranged as follows. Firstly, Hyeonmoyangcheo-ism in homekeeping textbooks in the 1950s stressed the modern housewife. The Confucianwomen's virtues, such as submissiveness, faithfulness and samjongjido (obedience to father, husband and son), that were in girls' moral training and home management textbooks during the Japanese imperialism. This was a part of girls' education built on democracy and equality asserted by a new Korea, the 'modern nation'. Secondly, with the increasing demands for women's labor after the Korean War, women's occupations were reinforced and incorporated in homekeeping textbooks in the 1950s. Even though having a job was a secondary task to the role of a homemaker, the details of women's occupation illustrates the characteristics of Hyeonmoyangcheo-ism in this period of time. Thirdly, The resident practice program emphasized the tradition women's behavior along with the modern homemaker, the rational designer of homekeeping. This seems to have been reinforced from the criticism towards women based on Westernization after the Korean War.