• 전기학회논문지
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• 제57권10호
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• pp.1726-1730
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• 2008

In this paper, the application schemes for coordinated control system of multiple FACTS were presented to enhance the voltage stability around the metropolitan areas. In order to coordinated control of FACTS devices, f-V analysis method which is one of the indices for voltage stability was performed with real time network data which is transferred from SCADA/EMS system. If the system is unstable after contingencies, the new operation set-point of FACTS would be determined using bus sensitivity from tangent vector at voltage instability point. Otherwise, we would determine the new operation set-point of FACTS for considering economical operation, like as active power loss minimization using Optimal Power Flow algorithm. In simulation, the SCADA/EMS 2007's data are used for studying the coordinated control algorithm of multiple FACTS devices that is installed or will be installed in KOREA power system

• Journal of Electrical Engineering and Technology
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• 제4권4호
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• pp.451-456
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• 2009

Through the development of phasor measurement units (PMU), various aspects of power system dynamic behavior could be monitored and diagnosed. Monitoring dynamic voltage stability has become one of the achievements we can obtain from PMUs. It is very important to select the most appropriate method for the Korea Electric Power Corporation (KEPCO) system since there are many voltage stability indices. In this paper, we propose an advanced WAVI (Wide Area Voltage Stability) that is well suited for the purposes of monitoring the dynamic voltage stability of KEPCO's PMU installation plan. The salient features of the proposed index are: i) it uses only PMU measurements without coupling with EMS data; ii) it is computationally unburdened and can be applied to real-time situations. The proposed index is applied to the KEPCO test system and the results show that it successfully predicts voltage instability through comparative studies.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.602-607
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• 2004

Several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck trains have relatively big cross sectional areas and high mass centers that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures, and do not have enough spaces for electric equipments. Therefore, prior to operate double deck trains on the existing lines in Korea, careful investigations should be performed. In this study, we have roughly designed a double deck EMU train system for the existing lines around Seoul metropolitan area.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지하공간 건설기술에 관한 서울 심포지움 논문집
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• pp.3-30
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• 1993

To ease traffic congestion Seoul Metropolitan Government formulated the 2nd Phase of Seoul Subway Construction Scheme in 1989. The scheme calls for the construction of %60 km of subway which includes addition of 4 more subway lines and extension of 3 existing subway lines in addition to the existing 118 km of subway. As a final stage of the scheme subway line 6 is under planning and design. The line 6 is 36.1 km-long route connecting Ungam-Samgakchi-Changsin-Sinnae. Except for the depot main line wilts be underground and major construction methods are cut and cover and tunnelling. As a tunnelling method New Austrian Tunnelling Method will be adapted. The line will be opened by the end of 1997. With the completion of the line Seoul will have 278 km of subway network and the transport share by subway will be increased from 25% in 1992 to 50% in 1997.

• 전기학회논문지
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• 제58권12호
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• pp.2316-2321
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• 2009

With rapid development of world economics, electricity demand in metropolitan area has been increased dramatically. HTS(High Temperature Superconducting) cable is one of most promising technology to solve the bottleneck of electric network. However, HTS cable is not considered as matured technology yet to power system planners because of its different characteristics with conventional metal conductors. This paper suggests the comparison results of HTS cable simulation and experiment on steady state operation, also give the simulation results on transient characteristics of HTS cable components. This results could devote not only to discuss the security of HTS cable operation, but also to design power system oriented HTS cable.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.169-171
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• 2010

The goal of this study is to evaluate the performance of different solution types(a GPS-only, a GLONASS-only, and a GNSS solution) on GNSS positioning modes which are point positioning and relative positioning(DGNSS-, Static-, and Kinematic-solutions). I started with GNSS sites of seoul metropolitan government's RTK network which providing combined GPS/GLONASS observations : Gangseo(GANS), Dobong(DBON). The positioning accuracy of different solution types on positining modes are compared. Considering the compared results of all cases, can find not only the difference of the performance between the GNSS solution and the GPS-only solution is very small, but also the GLONASS-only solution is not far from the other solution types taking into consideration that GLONASS system is not (yet) a complete system.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 가을 학술발표논문집 Vol.34 No.2 (D)
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• pp.556-559
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• 2007

Due to its ease of deployment, low cost, self-configuring and self-healing capabilities, Wireless Mesh Networks (WMNs) have emerged as a key technology to be used in a wide scale applications in personal, local, campus, and metropolitan areas. Security and more specifically privacy is an important issue in this type of multi-hop WMN which has given a little attention in the research community. We focus on privacy compromise of a mesh client in a community mesh network that may lead an attacker to reveal mesh clients identity. his other profiles and gain information about mobility. In this paper. we have presented an authentication mechanism with the aid of blind signature that ensures a mesh client to anonymously authenticate itself with a nearby mesh router and thereby preserve identity privacy We have also presented the security and performance analysis of the proposed scheme.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.643-644
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• 2006

In this paper, WiBro system which is one of the mobile wireless metropolitan area network systems is presented. WiBro is an OFDMA system which has a sub-channelization process unlike conventional OFDM systems. The sub-channelization is the time consuming processing, so a time-efficient hardware architecture is needed. WiBro RAS(Radio Access Station) demodulator is designed with Verilog HDL, and the gate count is 81k using the $0.18{\mu}m$ processing.

• Journal of Contemporary Eastern Asia
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• 제10권2호
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• pp.35-40
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• 2011

The recent listing of Preah Vihear Temple as a World Heritage Site has awakened a longtime simmering border dispute between Thailand and Cambodia over a few square kilometers surrounding the ancient Khmer Temple. While the listing of the site by UNESCO was expected to revive the economy of the impoverished border towns near the temple due to the increased tourism and funding for the preservation of the archeological site, it has had the opposite effect due to the sharp increase in violent conflict carried out by the armed forces and nationalist activists from both sides. Military skirmishes and violent protests have brought the local economy to a halt in addition to causing considerable physical damage to the local infrastructure and to the local transnational network of ethnic Kui, local business owners, Khmer and Thai villagers. This paper shows how the dispute is viewed and undertaken by three distinct communities involved in the conflict, the militaries, the metropolitan political elites and activists, and the local villagers. The three communities represent three different cultures of conflict with different interests and most importantly with differential access to the media and official representations of the dispute.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 춘계학술대회
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• pp.86-87
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• 2013

해운 항만의 환경이 2000년대 들어서 10,000teu급의 대형 컨테이너선박이 집중 투입되면서 선박의 대형화와 고속화가 가속되고 있다. 이에 따라 전세계 해운시장의 업계들은 살아남기 위한 방안으로 M&A와 Alliance들을 선택하였다. 각각의 선사들은 주력하고 있는 항로들이 다르며 그에 따라 전략적인 제휴관계를 맺고 있다. 본 연구에서는 전 세계 해운 선사들의 Alliance 관계를 파악하고 그들의 사회연결망기법중의 하나인 Net-miner4를 활용하여 네트워크 구조에 대해서 깊이 있게 살펴보았다.