• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.1
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• pp.29-34
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• 2005

The wound induction motor can provide high starting torque and reduced starting current simultaneously by inserting large resistor externally when starting. And this technique is one of the well known methods among the induction motor starting methods and generally used for heavy load starting such as crane and cement factories. The conventional PI controller has been widely used in industrial application due to the simple control algorithm and is generally used for control of current torque, position, and speed for the wound induction motor drive system. However, the conventional control system for wound induction motor may result in poor performance because sensors have to be used but are often limited by the environmental condition. Recently, to overcome these problems, many sensorless vector control methods for the wound induction motor have been studied. This paper presents a MRAS method for sensorless vector control of the wound induction motor drive. In the conventional MRAS method, in low frequency, the stator resistance variation may result in poor performance. Therefore, this paper presents a MRAS method with stator and rotor resistance tuning for sensorless vector control of the wound induction motor to overcome several shortages of the conventional MRAS caused by parameter variation and to enhance the robustness of the sensorless vector control. The validity and effectiveness of the proposed method is verified through digital simulation.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.472-483
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• 2013

Actual maritime exercise for improving the capability of submarine sonar operator leads to a lot of cost and constraints. Sonar simulator maximizes the capability of sonar operator and training effect by solving these problems and simulating a realistic battlefield environment. In this study, a passive sonar simulator algorithm is suggested, where the simulator is divided into three modules: maneuvering module, noise source module, and sound propagation module. Maneuvering module is implemented in three-dimensional coordinate system and time interval is set as the rate of vessel changing course. Noise source module consists of target noise, ocean ambient noise, and self noise. Target noise is divided into modulated/unmodulated and narrowband/broadband signals as their frequency characteristics, and they are applied to ship radiated noise level depending on the vessel tonnage and velocity. Ocean ambient noise is simulated depending on the wind noise considering the waveguide effect and other ambient noise. Self noise is also simulated for flow noise and insertion loss of sonar-dome. The sound propagation module is based on ray propagation, where summation of amplitude, phase, and time delay for each eigen-ray is multiplied by target noise in the frequency domain. Finally, simulated results based on various scenarios are in good agreement with generated noise in the real ocean.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.321-327
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• 2020

Engine oil leaks comprise the largest percentage of the major quality problems that have occurred during the engine production process for military land system equipment over the last two years. To minimize this, it is essential to understand the root cause of the engine oil leakage and perceive the more common leakage area, as well as reduce the quality costs of pre-identification for leaks in the engine assembly process and single items. Therefore, in this study, the mass production quality of engines installed and operated in power equipment was improved by visualizing the engine oil leakage injected with the fluorescent dye and increasing the identification of the engine oil leak phenomenon. For this reason, the possibility of substituting the engine oil was considered and the engine oil was injected with the fluorescent dye. The maintenance was improved by reforming the engine oil injection process and leakage inspection process. Finally, these results suggest that the quality costs between mass production processes can be minimized by ensuring the reliability of military engines by reducing the user's complaints and improving the quality control capabilities of engine manufacturers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.117-124
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• 2019

Military Vehicles of the Korean army had been developed before 2004 and used manual transmissions. Manual transmissions contain a clutch system regulating the force from engine to transmission. In this study, a 2.5-ton military vehicle's clutch system was investigated. The existing clutch system had the characteristics that need to adjust the clearance between the clutch cover and release bearing. Improper clearance led to early wear of the clutch disk and failure of the clutch cover. To solve these problems, an improved clutch system was suggested and tested. The improved clutch system contains auto adjustment of the clearance and an enhanced clutch disk. To verify the improved clutch systems, 2 stage tests were conducted: an accelerated life test of the clutch system, and a driving test by trainee of driving more than 3,000km. As a result, the problems caused by the improper clearance adjustment were solved and this design was verified.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.613-618
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• 2023

The advancement of Information and Communication Technology (ICT) is accelerating innovation across society, and the defense sector is no exception as it adopts technologies aligned with the Fourth Industrial Revolution. In particular, the Army is making efforts to establish an advanced Army TIGER 4.0 system, aiming to create highly intelligent and interconnected mobile units. To achieve this, the Army is integrating cutting-edge scientific and technological advancements from the Fourth Industrial Revolution to enhance mobility, networking, and intelligence. However, the existing addressing system, IPv4, has limitations in meeting the exponentially increasing demands for network IP addresses. Consequently, the military considers IPv6 address allocation as an essential process to ensure efficient network management and address space provisioning. This study proposes an approach for IPv6 address allocation for the future military, considering the Army TIGER system. The proposal outlines how the application networks of the Army can be differentiated, and IP addresses can be allocated to future unit structures of the Army, Navy, and Air Force, from the Ministry of National Defense and the Joint Chiefs of Staff. Through this approach, the Army's advanced ground combat system, Army TIGER 4.0, is expected to operate more efficiently in network environments, enhancing overall information exchange and mobility for the future military.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.352-362
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• 2016

In this paper, a disposal maneuver which complies the space debris mitigation guideline was analysed for KOMPSAT-2 as an example of LEO satellite. Definition of disposal altitude which comply the '25 year rule', re-entry survivability analysis of KOMPSAT-2 parts inside and casualty area analysis were performed using STK and ESA's DRAMA. Finally, assuming that there were several survival objects during uncontrolled re-entry stage, the re-entry initial orbit elements which show the low casualty probability were found even if there were various uncertainties about the initial orbit. As a result, KOMPSAT-2 should be descended its altitude at least 43km or up to 105km to comply '25 year rule' and there were heavy or heat resistant survival objects which generated $4.3141m^2$ casualty area. And if RAAN of re-entry initial orbit was 129 degree, total casualty probability was lower than standard value of space debris mitigation guideline even if there were uncertainties about the initial orbit.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.2
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• pp.107-115
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• 2007

Among public transportation facilities within urban area, electric railway (subway) has been a regionally based facility that has played an important role in improving the foundation of territory development and arrangement of living foundation and living environment while supplementing the regional road network. In this regard, the subway stations should be allocated in the right place to ensure mobility, convenience and economic feasibility, some of transportation characteristics of road network combined with the subway. However, it would be very hard to evaluate quantitatively the effects of public transportation facilities such as subway in metropolitan cities on regional development and change in land use and to suggest the data that would be utilized in future city planning corresponding to their results. Therefore, this study evaluated the change in land use by the conditions of location of subway stations quantitatively; then, it evaluated and analyzed the change in land use for the internal and external parts of the surrounding areas of subway stations through the GIS spatial analysis and classification of landsat TM satellite image for utilizing it as reference material for the new establishment of subway stations in the future.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.10a
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• pp.234-235
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• 2004

현재 자동차의 변화를 이끄는 흐름에서 가장 핵심이 되고 있는 유형 Sport Utility Vehicle은 전천후 기동성 측면과 Sports성을 중심적인 특성으로 다루고 있다. 그러나 SUV로서 off road 중심의 공간 활용 보다는 실내 공간 중심의 활용이 더욱 중요한 특성으로 자리잡고 있다. 이러한 경향은 주 5일 근무 정착에 따른 여가 시간의 증가와 아울러 보다 다양한 직업과 생활 패턴 등에 따라 더욱 두드러질 것으로 보인다. 이러한 근 미래 변화에 대응하는 방법으로 기존의 SUV type에서 탈피하여 sports성을 반영하는 동시에 보다 utility적 활용 중심의 특성을 가지는 XUV (eXtreme Utility Vehicle)라는 새로운 유형을 2010년 시점의 근 미래 테크놀러지와 조형성의 동향 예측, 사용자 요구점 분석 포지셔닝 등을 통해 제안한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.344-347
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• 2011

This paper presents qualification process of the T700/701K turbo-shaft engine for Korean Utility Helicopter(KUH). The T700/701K is the rear-drive variant of the GE's T700-701C/D engine which was qualified for military applications in the world. The main scope of the development is the modification from a front-drive engine to a rear-drive one, the performance enhancement of the power turbine and the incorporation of two channel FADEC(Full Authority Digital Engine Control) system for more reliable operation. Therefore, T700/701K engine must be qualified by Korean government in order to perform a flight in the country. Reflecting the influence of developing scope, the main requirements including performance and control are verified by test and analysis, while the requirement for module or component that is same to that of T700-701C/D are verified by similarity.

• Journal of Sericultural and Entomological Science
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• v.38 no.1
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• pp.13-18
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• 1996

To secure the genetic resources of silkworm, Bomyx mori, the cDNA library was constructed with mRNA isolated from fifth instar larvae. Titer of the cDNA library was about 1.3 X 106 plaques in total. We presumed that the titer covered all transcripts existed in Bombyx mori. Meanwhile, it is knowen that partial cDNA sequences, Expressed Sequence Tags(ESTs), have a good value for the discovery of novel genes and the elucidation of their structures. For this purpose, partial cDNA sequencing was carried out from randomly selected cDNA clones in the library. Partial cDNA sequences of 37 clones were determined and an average of 212 nucleotides of sequence can be read from the clone. The ESTs were searched in GenBAnk database and fifteen ESTs showed significant similarities to enlisted sequences. They included the genes of storage protein, heat shock protein, actin, catalase and so forth. We presumed that the 22 unmatched ESTs were novel genes.