• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1877-1882
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• 2007

The Yongsan International Business District development work is a 20 billion$ project to raise facilities for national business, trade, residence, and culture. The project site is $566,800m^2$ and it covers the railroad maintenance center and Dongbuichon-dong. Developing railroad station region used to be done by private investment. However, problems existed; simple function as a massive selling market, traffic jam caused by massive market users, inadequacy to transfer to other transportations, interruption of the pedestrian way and separation of zone of life by the station. To solve this problem it is important to consider developing cases of other countries and devise a plan that is applicable to our circumstances. In the study, we compared our station development case with foreign station development cases and analyze the element for the plan what we should consider in our station development. In addition, The results of the study can be used as a preliminary data in the future planning the Yongsan International Business District development.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.73-76
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• 2007

For the space communication between a satellite and a ground station, spacecraft performs data packeting and data coding. Using standard format certainly has an advantage but depending on the hardware implementation sometimes compliance with the standard is hard to accomplish. This paper studies the suitable way to transfer image data and ancillary data to the ground station in the format of CCSDS recommendation.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.303-312
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• 2010

VHF Omnidirectional Radio range(VOR) is used as an aircraft navigational aid. The VOR is a short-range air navigation system providing aircraft with its bearing relative to the ground station. The accuracy of a VOR must be checked in accordance with the current ICAO, FAA and domestic regulations. The primary purpose of performing VOR station ground checks is to minimize the need for expensive flight checks by determining the amount and direction of any course bearing inaccuracies being transmitted. In this paper we present current and advanced way of monitoring of VOR system. We verify this way by field test of the monitoring and it is a high performance way to achieve an improvement in accuracy and an effect compared to present monitoring system.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.70-70
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• 2017

TSV(through silicon via)는 긴 종횡비를 갖는 패턴에 Cu, Ta, Ti을 높은 conformality를 갖도록 증착하는 공정이다. Magnetron cathode의 자석 배열 설계는 target 물질 종류에 따라서 multitrack, water drop type등이 있으며 target과 substrate 사이의 공간에 플라즈마를 형성시켜서 기판에 이온 입사량을 늘린 후 기판 바이어스를 이용하여 이온 충돌, re-sputtering을 통한 재증착 과정을 통해 치밀한 금속 박막을 연속적으로 형성할 수 있도록 하는 것이 목적이다. 또한 sputter가 사용되고 있는 분야에 효율을 증대시키고, 증착되는 막의 품질향상을 위해 UBMS를 사용하고 있으며, 산업에 사용되어 지는 300 mm wafer용 시스템은 제작비가 약 10억 원 정도 소요되며 다양한 테스트를 진행하기 위해선 많은 비용이 소요된다. 따라서 비용과 소요시간을 줄여 다양한 테스트를 위해 소규모 플라즈마 시스템을 설계하게 되었다. 61 l/sec 터보 분자 펌프와 다이아프램 펌프를 기초로한 TMP station에 2.75 인치 CF flange가 장착된 6 way cross를 main 챔버로 활용하고, 작은 size의 unbalanced magnetron cathode를 제작, 장착한 다음 6 way cross 주변에 전자석을 적절히 배치하여 300 mm wafer system에서와 동일한 물리적 현상을 테스트 할 수 있도록 하였다. Fig1. (a) UBMS system의 사진을 나타내었고, (b)에는 6 way cross 내부에 발생된 플라즈마의 형상을 나타내었다. 전원 장치는 Advanced Energy사의 MDX-1.5K DC power supply를 사용하였고, 방전 전압 - 전류 관계의 가스 압력에 따른 plasma 현상과 magnetron 배율에 따른 plasma 현상 그리고 전자석에 의한 영향을 주로 관찰 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1415-1423
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• 2007

Total efficiency of transmitter system was improved by developing combinational 2-Way Isohybrid for GSM1900 base station in this paper. The size of product was decreased and the characteristics were stabilized. The isohybrid transmitter combiner of chip coupler type and hybrid coupler type were designed and fabricated. Insertion loss for chip coupler type isohybrid was $3.17\;dB{\sim}3.47\;dB$. On the other hand, insertion loss for hybrid coupler type was $3.17\;dB{\sim}3.42\;dB$. Isolations between ANT and port were $24.23\;dB{\sim}29.98\;dB$ in case of chip coupler type Isohybrid and were $26.28\;dB{\sim}36.91\;dB$ in case of hybrid coupler type, respectively.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.396-403
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• 2019

Metro stations are public places used by many people. If they use the station frequently, there is no struggling to find a way. But the first tourists or foreigners to visit are facing finding difficulties because of errors of the complicated sign and information. This study is the guidance of the metro station sign to provide effective information system and the research on the design improvement of metro station. In the first survey for this study I proceeded research about the concept of sign systems in metro station and literature search. In the second survey, I researched needs of the problems of the metro station users. In the third survey, I investigated Busan Metro Station's problems and design to improve the guide sign. In the survey results, users had a lot of difficulties in finding information because systematically increasing amount of information and guidance of the metro station. People can't find information because of sign indiscreet commercial advertising. Also they can get false information from sign without unity. To deal with these problems the metro station needs to improve design for a second-class citizen and refrain commercial advertising and design for information transfer capability.

• Journal of Agricultural Extension & Community Development
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• v.14 no.1
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• pp.59-91
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• 2007

The objectives of this study were 1) to explore the present status of extension services of agricultural experiment station, and 2) to get some implications for ameliorating extension services of agricultural experiment station. The data were collected through the semi-constructed interviews with 11 agricultural researchers in 6 local agricultural experiment stations and 11 farmers who have ever made contact with the researchers. The major findings of this study were as follows: The agricultural experiment stations were providing extension services as expedients to accommodate to new markets and structural changes of organizations, though they are originally research-oriented agencies. The extension methods of agricultural experiment stations were similar with those of extension agencies, and the extension methods used mainly were 'experiment plot demonstration exhibition', 'consultation using telephone, internet, face to face meeting', 'visiting farms and consulting'. These were generally carried out by farmer's request, therefore the extension services of agricultural experiment stations were provided in a passive way so far. Based on the results of this study, the followings are recommended for further development of extension services of agricultural experiment station: The rural development organizations should set principles and support for extension services of agricultural experiment stations. The alternative plans to strengthen the linkage between research and extension have to be made, and these plans should include financial, personnel and systematic arrangements for further development of extension services of agricultural experiment stations.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.4
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• pp.87-94
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• 2016

This paper proposes an energy transmission method to maximize energy efficiency of a based station. This method makes use of classification of service type to solve an inefficient use of transmission power, which is from exponential relationship between the legacy data throughput and transmission power. The proposed one is a way to find the most energy-efficiency points with the transmitted optimal amount of data on users in a base station of wireless network environment. For this, we propose EETA (Energy-Efficient Transmission Algorithm) which can control the amount of data and the holding time at the base station. As a result, the proposed method can improve the energy efficiency of about 10% compared to the legacy base station.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.390-390
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• 2019

Application of Hidden Markov Model (HMM) to the hydrological time series would be an innovative way to identify extreme rainfall events in a series. Even though the optimum number of hidden states can be identify based on maximizing the log-likelihood or minimizing Bayesian information criterion. However, occasionally value for the log-likelihood keep increasing with the state which gives false identification of the optimum hidden state. Therefore, this study attempts to identify optimum number of hidden states for Colombo station, Sri Lanka as fundamental approach to identify frequency and percentage of extreme rainfall events for the station. Colombo station consisted of daily rainfall values between 1961 and 2015. The representative station is located at the wet zone of Sri Lanka where the major rainfall season falls on May to September. Therefore, HMM was ran for the season of May to September between 1961 and 2015. Results showed more or less similar log-likelihood which could be identified as maximum for states between 4 to 7. Therefore, measure of central tendency (i.e. mean, median, mode, standard deviation, variance and auto-correlation) for observed and simulated daily rainfall series was carried to each state to identify optimum state which could give statistically compatible results. Further, the method was applied for the second major rainfall season (i.e. October to February) for the same station as a comparison.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.113-128
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• 2021

In this paper, we present a simple ground receiving station as an educational method for a satellite system. Our system is produced similarly to the existing fixed ground station in terms of function by using satellite communication technology and related software commonly used in the amateur radio field. In addition, we conducted operation test to receive signals from operating satellites and confirmed the possibility of using them as a way to educate satellite systems, such as understanding ground station systems through satellite reception experience and satellite state information acquisition, and further designing satellite systems.