• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.2
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• pp.114-123
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• 2017

Little Intelligent Nanosatellite of KAIST(LINK) is a 2U-size CubeSat which is developed by Aerospace Systems & Control Lab.(ASCL) of KAIST as a part of the international cooperation project QB50. The objective of the QB50 project is to carry out atmospheric research within the lower thermosphere and ionosphere and CubeSats are planned to be deployed at the International Space Station(ISS) from the first quarter of 2017. To implement this objective, a flight model(FM) of LINK has been successfully developed and the design and performance of the satellite have been verified by performing environment and function tests in accordance with acceptance requirement level. This paper describes the development of flight model and the results of vibration and thermal vacuum test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.322-325
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• 2007

This paper shows the development procedure of the low pressure LOX feed system which is used in the liquid rocket with a turbopump. Korean Air has cooperated with KARI in developing the LOX feed system to turbopump. The LOX feed system is characterized with cryogenic temperature and the thin-thickness tube for weight saving. The system in this project is composed with a main feed line and a recirculation line for the LOX temperature conditioning. Each piping system has many components, namely, bellows, filter, orifice, valves, flange and support. In this paper, system design & manufacturing, structural & thermal analyses, and component tests are explained. Finally, the system was assembled to the KARI's PTF test facility and functioned well to meet its required performance.

• The Journal of the Korea Contents Association
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• v.3 no.4
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• pp.38-47
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• 2003

Distributed problem solving is the cooperative solution of problem by a decentralized and loosely couped collection of knowledge-sources (KS's), located in a number of distinct processor nodes. The contract net protocol has been developed to specify problem-solving communication and control for nodes in a distributed problem solver. Task distribution is affected by a negotiation process, a discussion carried on between nodes with tasks to be executed and nodes that may be able to execute tasks In this paper, we present the coordination method among distributed intrusion detection system and firewall by the contract net protocol. The method enhances the intrusion detection performance and provides the communication methods. To mode IDS and firewall, security models hue been hierarchically constructed based on the DEVS (Discrete Event system Specification) formalism. Each ID agent cooperates through the contract net protocol for detecting intrusions. The IDS which detects the intrusion informs to firewall, so the harmful network traffic is blocked. If an agent detects infusions, the agent transfers attacker's information to a firewall. Using this mechanism attacker's packets detected by In can be prevented from damaging the network.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.104-113
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• 2009

Recently, high-speed Internet users and broadband network infrastructure are increasing. However, the TCP protocol widely used in the Internet is an appropriate transport only for the legacy Internet, it is inefficient for traffic transport for network environments with large bandwidth-delay product. In order to remedy this problem, there have been many researches about improved congestion control algorithms for broadband networks. In these studies, most of performance evaluation has been done by simulations. In this paper, after we reviewed the proposed high bandwidth transport layer protocols, we implemented a real testbed, measured the performance and analyzed the problems of high-speed transport protocols through the international research network TEIN2 between three nations, Korea, China, and Germany.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.545-553
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• 2017

This paper investigates a synchronization algorithm for a distributed network which does not have a centralized infrastructure. In order to operate a distributed network, synchronization across distributed terminals should be acquired in advance, and hence, a plenty of distributed synchronization algorithms have been studied extensively in the past. However, most of the previous studies focus on the synchronization only in fault-free networks. Thus, if there are some malfunctioning terminals in the network, the synchronization can not be guaranteed with conventional distributed synchronization methods. In this paper, we propose a reliability-based adaptive consensus algorithm which can effectively acquire the synchronization across distributed terminals and confirm performance of the proposed algorithm by conducting numerical simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.87-98
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• 2008

Electronic Navigational Charts (ENCs) are digital charts encoded in S-57 format, which contain navigational informations such as coastlines, depth areas, and nautical marks. Although they have been successfully used for the safe navigation of ships, they have limited usages and applications because of their specialized data format and access systems. To cope with such drawbacks, S-57 ENCs need to be transformed into more generalized format such as Geography Markup Language (GML). The transformed GML ENCs can be kept in a database for efficiency, and can be accessed through Internet for usability. This paper proposes a new method for transforming and managing ENCs with XML database. S-57 ENCs are lust transformed into GML format, and then stored in a XML database. On the database, users can query for their needs. To validate the feasibility of the proposed method, we developed a protype system, and then conducted several test runs. The system can provide users with easy access to the marine information contained in ENCs. It also provides compatibility and efficiency by virtue of GML and XML database, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2059-2071
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• 2007

If the correct structure of Web site is known, the information provider can discover users# behavior patterns and characteristics for better services, and users can find useful information easily and exactly. There may be some difficulties, however, to extract the exact structure of Web site because documents one the Web tend to be changed frequently. This paper proposes new method for extracting such Web structure automatically. The method consists of two phases. The first phase extracts the hyperlinks among Web documents, and then constructs a directed graph to represent the structure of Web site. It has limitations, however, to discover the hyperlinks in Flash and Java Applet. The second phase is to find such hidden hyperlinks by using Web access log. It fist extracts the click streams from the access log, and then extract the hidden hyperlinks by comparing with the directed graph. Several experiments have been conducted to evaluate the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.127-135
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• 2006

In the existing education using the globe. teaching contents are very simple and the relationship among learning units lacks a little bit because teaching materials are composed individually with the globe. Therefore, in this study, we developed the education glove system based on multimedia that is closely connected with teaching materials and the globe. This system is composed of the globe device and the learning software based on computer control. The globe device rotates itself on its axis as the solar center, and provides more efficient and visual education environment to students through the link between computer and the globe. The learning software provides the multimedia contents such as parallax, climate, culture, and education information about each country, and this software also can simulate the revolution of the earth around the sun. The globe device can be operated in off-line without the computer link. This system was developed by the industry cooperation and was displayed in the principal exhibitions. We have obtained positive results through the exhibitions and will promote the product in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.181-186
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• 2022

The world's electric automobile sector has shifted beyond technological environmental changes to a stage that has an impact on the market environment. And automakers are shifting from the existing strategy of "technological advantage → brand enhancement → sales expansion of existing internal combustion engine vehicles" to the expansion of the electric automobile market itself, which is to enhance market competitiveness. In addition, competition in the electric automotive parts market is expected to intensify due to the expansion of the business areas of existing parts makers and the entry of new companies, and development cooperation is expected to actively proceed to improve the efficiency of major eco-friendly parts. Along with this prospect, electric vehicles are expected to change the overall structure of the automobile industry, the overall growth of the electric vehicle value chain such as batteries, power trains (motors, power management and control systems), electric vehicle production, and charging infrastructure Is expected. Therefore, in this thesis, in order to cultivate a variety of high-quality human resources that companies want to keep pace with the changing automobile industry, we study a professional manpower training program that leads the growth engine of the electric automobile industry.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.457-483
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• 2023

As ISNI spreads, the process and utilization method of authority control that identifies and links individual or group names is also expanding. In this study, the characteristics of the connection and utilization of ISNI and national authorities in the United States, the United Kingdom, France, and Germany were derived, and a plan to improve the connection and utilization of national authorities and ISNI was presented, focusing on the National Library of Korea. Focusing on major countries actively participating in the establishment and utilization of ISNI since its founding, national authorities and ISNI linkage methods and ISNI data used in services were analyzed. The implications of this study for the linkage and convergence of national authority and ISNI data were: first, applying ISNI to support authority work, second, establishing a close cooperation system with the publishing community, and third, establishing infrastructure for linking ISNI and authority records at the national level, and finally, providing user service pages based on authority data.