• Proceedings of the KSR Conference
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• 2001.10a
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• pp.179-186
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• 2001

As the freight traffic becomes heavier, the high speed of existing freight cars is essential instead of the construction of a new railway. The high speed can be achieved by the design modifications of the freight bogie. In this paper, an analytical model of freight bogie including the lateral force between rail and the flange of wheel is developed to decide the critical speed, which activates a hunting motion and tells the running safety of freight bogie. The dynamic responses of the analytical model were compared with an experimental data from a running test of a freight bogie and showed good agreements between them. The analytical model is used to find the design modifications of the freight bogie by parameter studies. The results show that the reduction of wheelset mass ratio and the increase of the axle distance of the freight bogie can increase the critical speed, but the primary lateral stiffness has little effects on the critical speed. And this also study shows that smaller wheel conicity deteriorates the running safety of the freight car, which means the overhauling of the wheel of freight bogie should be done regularly.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.188-193
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• 2007

Airport railroad have required maximum design speed 120km/h and wind speed 50m/s condition as design item of airport railroad vehicles. To design and manufacture the vehicle satisfying these conditions, it must carry out the dynamic behaviors analysis such as hunting stability, ride comfort derailment ratio, unloading ratio and lateral force to meet the criterion described in Urban Railroad Act. Dynamic behaviors of vehicle have carried out using the multi-body dynamics simulation program(VAMPIRE). This paper presents the evaluation methods and criterion used to verify dynamic performance of airport railroad vehicle, and show the analysis results of vehicle dynamic simulation and the test results for vibration and ride comfort measured on running performance tests. As a results, each analysis results and test results meet the criterion described in Urban Railroad Act.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.84-89
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• 2001

Studied in this paper was the vehicle dynamics simulation for development of single axle bogie using the multi-body dynamics simulation program(VAMPIRE). Single axle bogie vehicle is to the crew of freight vehicle. Method of analysis for dynamic behaviors of vehicle having single axle bogie was carried by UIC(International Union of Railways) code 518 and results of analysis were presented in terms of the hunting stability and the derailment ratio and the sum of wheel/rail lateral force. The results of analysis meet the criteria proposed by UIC.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.110-117
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• 2013

Maximum Torque Per Amp (MTPA) control for induction motor drives seeks to achieve a desired torque with the minimum possible stator current. This is favorable in terms of inverter operation and nearly optimal in terms of motor efficiency. However, rotor resistance variation can cause significant performance degradation. This work demonstrates that existing MTPA controls perform sub-optimally as temperature varies. An adaptive MTPA control strategy is proposed that always achieves optimal performance without exhibiting hunting phenomenon regardless of rotor temperature. The proposed control is experimentally shown to accurately achieve the desired torque.

• Steel and Composite Structures
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• v.22 no.1
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• pp.183-201
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• 2016

Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

• The International Journal of Costume Culture
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• v.6 no.1
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• pp.30-37
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• 2003

The most distinctive feature of the costumes of the Arctic regions from Alaska to Siberia centering around the Bering Sea connecting Asia to North America, is that each tribe makes clothes adequate to the climate and their lifestyles with animal hides obtained from hunting in their habitation. Furs or fish skins, the main materials for clothing, are characteristically cut into many pieces, and thus piece-joining patchwork is used to make or decorate garments. Patchwork is the technique that can create new designs with 3-dimensional and various combinations by modifying the simple materials, and also has the advantage of fitting the body without a certain cut line. Therefore, the patchwork found in the Arctic costumes may be developed from folk costume designs with limited materials like fur into new ones for modern or future costumes.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.579-589
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• 2011

One of the most significant UUV(Unmanned Underwater Vehicle) applications is MCM(Mine Countermeasure), which makes good use of UUV characteristics to provide covert, rapid, controlled and efficient survey of a potential minefield without risking a human operator. In this paper, a survey of the today's MCM missions where UUVs will play a role, the vehicle systems that are either under development or planned in the future are presented. And examines principal technical challenges and outline new enabling technologies. Particularly, this paper analyses current approaches to tacking these technologies and technological limitation of UUVs as a MCM platform, and research efforts to develop the technology necessary to meet the domestic MCM mission needs.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.879-885
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• 2000

This study is carried out to make clear the reason of occurrence of sudden acceleration incident of AT vehicle. The stepping motor is used to control the engine speed at idle by compensating the volume of air. By the way it's valve is contaminated by blow-by gas, deposit and back fire etc. This contamination could occur the load of motor at low temperature. This plays an important role in damaging the motor's coil with the motor's performance interfered. If it's coil is damaged the ISC could malfunction. If these phenomena occur, the speed of engine may increase or the engine may stall with hunting.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.322-324
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• 2001

급속한 인터넷 발전과 사용자들의 증가에 따라 나날이 사용자 요구사항이 복잡 다양해지고 있다. 또한, 이러한 사용자 요구를 총족시키지 못하는 인터넷 업체는 뒤떨어지게 되어 있어 여러 가지 고객관리 기법들이 연구되고 있다. 그 중에서 개인별 성향을 분석하여 원하는 정보만을 선택하여 추천해 줌으로써 사용자와의 관계를 지속시키는 맞춤 서비스라는 것이 있다. 그리고, 이러한 서비스를 유선 인터넷뿐만 아니라, WAP 기반 무선 인터넷상에서도 제공해 줌으로써, 사용자들은 시간과 공간의 제약을 받지 않고, 이동 중에서도 원하는 정보를 얻을 수 있다. 본 논문은 에이전트를 이용하여 사용자별 구인/구직 성향을 분석하고, 이를 통해 가장 알맞은 사용자별 구인/구직 맞춤정보를 유/무선 인터넷상에서 제공해주는 시스템 모델을 제시한다.

• Journal of the Korean Society of Physical Medicine
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• v.1 no.1
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• pp.161-168
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• 2006

Purpose : The purpose of this study was carried out to review for hydrotherapy, phototherapy, cupping therapy, therapeutic touch and massage as a Korean traditional physical therapy. Methods : This is literature study with books, and thesis. Results : The physical therapy that is in use nowadays has been around since human being started to live on the earth. In primitive times, when men were injured while hunting, they washed the wound in clinic water and dried it out in the sunshine, they also soaked their bodies in hot springs to decrease physical fatigue, Heating of injured tissue has been used for centuries for pain relief and muscle spasm. Conclusion : Korean traditional physical therapy has been developed and its scientific effects has been proven, It is required, to continue to carry out studying on this field.