• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.83-91
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• 2005

This paper describes the structural strength test technique and the results for cylindrical supersonic vehicle subjected to both aerodynamic load and thermal load. The special positioning system using spring links was designed to float, support and restrain the test airframe during the test and the down-time. The hydraulic system and the electric heating system were utilized to apply the aerodynamic load and the thermal load to the test airframe together. Particularly, several hundreds of infrared quartz lamps were used for the heating system, and the thermal test conditions were successfully simulated. The test results showed that this kind of high temperature test is adequate to verify the structure integrity and produce useful engineering data which is necessary for the possible structural modification under thermal environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.717-720
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• 2007

This paper presents a novel scheme that quickly searches for the optimal direction of multiple directional antennas, and locks on to it for high-speed millimeter wavelength transmissions, when communications to another antenna directional are disconnected. The proposed method utilizes a modified genetic algorithm, which selects a superior initial group through preprocessing in order to solve the local solution in genetic algorithm. TDD (Time Division Duplex) is utilized as the transfer method and data controller for the antenna. Once the initial communication is completed for the specific number of individuals, no longer antenna's data will be transmitted nil each station processes GA in order to produce the next generation. After reproduction, individuals of the next generation become the data, and communication between each station is made again. In order to verify the effectiveness of the proposed system, simulation results of 1:1, 1:2, 1:5 directional antennas and experiment results of 1:1 directionalantennas confirmed the efficiency of the proposed method. The 16bit split is 8bit, but it has similar performance as 16bit gene.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.971-978
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• 2005

In this paper, we design and fabricate a VCO(Voltage Controlled Oscillator) for radar detector of X/K/Ka band using frequency multiplier. The existing VCO operated in radar detector have many Problems such as narrow bandwidth, slow frequency variable rate, unstable of production due to high frequency. So we design and fabricate a VCO improved such problems using frequency multiplier. As a result of measure, investigated frequency multiple VCO show its output power 3.64 dBm at multiplied operating frequency 11.27 GHz and have wide frequency tuning range of 660 MHz by controlled voltage 0V to 4.50 V applied diode. And also its phase noise is -104.0 dEc at 1 MHz offset frequency so we obtain suitable performance for commercial use.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2619-2621
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• 2004

감마선 또는 x-선 등 방사선을 이용한 구조물 진단은 산업전반에 걸쳐 널리 이용되고 있다. 기존의 x-선이나 Ir-192의 감마선 등을 이용한 비파괴검사는 용접부의 확인이나 구조물의 내부 결점 확인과 같이 국부적인 진단에는 유용하나 석유화학산업에서 반응물의 분리 또는 정제 등에 많이 사용되고 있는 증류탑의 내부진단 실험에는 적합하지 않다. 증류탑은 목적에 따라 직경이 $3{\sim}10m$, 높이 $10{\sim}100m$에 달하는 대형 장치로서 내부의 이상현상에 대한 정확한 진단은 공정 전체의 가동효율 최적화에 결정적인 영향을 끼친다. 밀봉 감마선원으로부터 방출된 방사선의 투과율 변화를 증류탑의 반대편에 설치한 방사선 검출기로 측정하여 수직밀도분포(vertical density profile)를 구하여 증류탑의 내부현상에 대한 정확한 정보를 얻을 수 있는데 이러한 작업을 자동으로 수행할 수 있도록 한 것이 자동 증류탑 검사장치이다. 증류탑 진단장치는 크게 방사선 계측 및 데이터 전송회로, 방사선원부와 방사선검출부의 구동장치 및 구동회로, 데이터 수집 및 제어장치 둥으로 구성되어 있으며, 증류탑 검사를 자동화하여 진단결과의 신뢰도와 재현성을 향상시켰다. 본 논문은 방사선원과 방사선 검출장치의 위치를 자동으로 제어하면서 방사선 계측결과를 전송시키는 장치의 개발에 관한 내용으로서 개발된 장치의 소개와 산업현장 적용의 예를 소개함으로써 기존의 비파괴검사기술로는 진단할 수 없는 대형 증류탑의 진단에 효과적인 방사선 응용 계측장치임을 보이고자 한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.40-48
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• 2006

In this paper, we propose the EPTS(Emergency vehicle Priority Transit system) for a rapid drive or emergency vehicles at the crossroads. The EPTS is one part of real-time traffic management system in the advanced traffic management system. The EPTS needs the connection or a traffic control system and a DSRC system. It can be applied to the real traffic situation considered with other traffic elements. As the result it is possible for the EPTS to nonstop drive because it induces an efficient drive of emergency vehicles. It is also relatively safe at the crossroad, it is expected that the EPTS is suitable for a telematics service which values efficiency above everything else.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.133-142
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• 2010

As the ubiquitous technology has penetrated into almost every aspect of modern life, the research of the security technology to solve the weakness of security in the ubiquitous environment is received much attention. Because, however, today's security systems are usually based on the fixed rules, many security systems can not handle diverse situations in the ubiquitous environment appropriately. Although many existing researches on context aware security service are based on ACL (Access Control List) or RBAC (Role Based Access Control), they have an overhead in the management of security policy and can not manipulate unexpected situations. Therefore, in this paper, we propose a context-aware security service providing multiple authentications and authorization from a security level which is decided dynamically in a context-aware environment using FCM (Fuzzy C-Means) clustering algorithm and Fuzzy Decision Tree. We show proposed model can solve typical conflict problems of RBAC system due to the fixed rules and improve overhead problem in the security policy management. We expect to apply the proposed model to the various applications using contextual information of the user such as healthcare system, rescue systems, and so on.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.435-438
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• 2012

Today, In all fields, As combination of ubiquitous computing-based technologies between electronic space and physical space, has been active trend research about wireless integration sensor network between sensors and wireless technology. Also, but in ship is underway research about Ship Area Network(SAN) of intelligent ship to integrate wireless technology, ship is required SAN-bridge technology of a variety of wired, wireless network integration and heterogeneous sensor and interoperability of the controller and SAN configuration management technology of remote control. Ship keep safe of all the surrounding environment including crew besides structural safety and freight management monitoring. In this paper, for monitoring design such as on climate change detection and temperature, pressure about various structures, there identify technology trends for routing and data aggregation to use energy efficiency in wireless sensor network. And to analyze self-organizing clustering method, study For wireless sensor network configuration in ship.

• Journal of KIISE
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• v.45 no.3
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• pp.242-250
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• 2018

For high-quality software development, it is necessary to detect and fix the defects inserted. If defect management activities are not properly performed, it will lead to the project delay and project failure due to rework. Therefore, organizations need to establish defect management process and institutionalize it. Process standard models handle defect management in the area of project monitoring and control. However, small organizations experience difficulties in implementing and applying defect management process in a real situation. In this paper, we propose a defect management process for small organization which is designed in accordance with the characteristics of a small projects such as few participants and short development period. The proposed defect management process will be based on a tool chain with open source software such as Redmine, Subversion, Maven, Jenkins that support a defect management process and SW Visualization in systematic way. We also proposed a way of constructing defect database and various methods of analyzing and controlling defect data based on it. In an effort to prove the effectiveness of the proposed process, we applied the process and tool chain to a small organization.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.86-93
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• 2012

The emergence of cable TV, satellite broadcasting and IPTV provides viewers with a variety of TV programs. However, viewers' desire for watching their favorite TV program at convenient time has increased because of insufficient spare time. As an increase in smart phone market has accelerated an entry into "the age of smart network media" since 2009, mobile media suggests services connected to other digital devices. Recently, there has been growing interest in TV controling system of smart phone. Therefore, the present study aims to provide an concept of the smart phone application which recommends contents of TV program by analyzing personal watching pattern. To suggest detailed direction of the interaction and UI design, we analyzed previous research and examples of TV controlling applications and products. In addition, public opinion survey was carried out to rationalize this study and suggest suitable UI structure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1307-1315
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• 2017

While the PSK mode of the DTLS is the most efficient in terms of the performance, it is not easy to pre-distribute and manage the symmetric key pairs as the number of sensor devices increases. On the other hand, both the RPK and certificate modes offer a convenient key management tool, but they do not guarantee a good computational performance. In this paper, the end-to-end security protocol suitable for the constrained devices is proposed, based on both the ECQV certificate and the PSK mode. Namely, the initial DTLS handshake is performed using the ECQV certificate, and the subsequent DTLS handshakes with the other CoAP servers in the same group are performed using the PSK mode for the purpose of reducing the overall computational load. Furthermore, a fine-grained access control for the CoAP client can be enforced to allow access to the limited number of CoAP servers.