• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.839-841
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• 2012

본 논문은 지형을 고려한 전파항법신호원의 최적 배치에 대한 연구이다. 전파항법신호원을 지상에 배치 할 때 고도에 따른 신호원 간의 가시선 확보를 위해 배치위치를 일정 범위 내에서 최적의 위치를 찾도록 하는 알고리즘을 적용하였다. 그리고 다양한 배치에 따른 측위 정확도를 이론적인 연구결과를 이용하여 분석한 결과를 제시하였으며 전파항법신호원의 배치를 위한 시뮬레이터를 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.282-285
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• 2011

효과적인 수술 훈련 시뮬레이터를 구축하기 위해서는 사실적인 훈련 환경을 제공하는 것뿐만 아니라 훈련 결과를 바탕으로 사용자의 숙련도를 객관적으로 측정하고 평가하는 과정 또한 중요하다. 이를 위해 본 연구는 수술 훈련 중 큰 비중을 차지하는 절개 동작에 대한 정량적 평가 척도를 제공하는 것을 목표로 한다. 사용자가 가상 장기 모델에 대해 절개를 수행하는 동안 평가 시스템은 절개 경로와 깊이를 일정 간격으로 샘플링하여 저장하고, 이를 두 곡선 간의 유사성 측정 알고리즘을 통해 훈련 시나리오 상에 정의된 표준 절개 경로와 깊이, 속도를 각각 비교한다. 이렇게 계산된 두 경로 사이의 거리가 가까울수록 유사성이 높은 것으로 간주하며, 사전에 설정된 기준치 이상의 유사성을 기록할 경우 훈련 목표를 충족한 것으로 판단할 수 있다. 본 연구에서는 단순 거리 측정에 의존한 일반적인 경로의 유사성 판단 알고리즘의 문제점을 제시하고, 전체 절개 경로의 길이 대비 현재까지 진행된 정도를 매개변수로 하는 방법을 이용하여 절개 경로의 방향을 고려한 유사성 측정 알고리즘을 제안하였다. 이와 같이 정량적이며 자동화된 절개 숙련도 평가 기법을 제안함으로써 사용자의 훈련 결과에 대해 보다 객관적인 피드백을 제공 할 수 있다.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.665-669
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• 2009

When maneuvering a ship in a narrow channel or under bridge, the ship operator may take actions of slowdown engine and altering course in order to avoid possible navigational dangers, which may reduce difficulties on navigation or collsion avoidance against other ship and/or bridge. In this paper, taking notice of the stress caused by these actions of slowdown engine and altering course, survey is carried out for whether it is possible to quantify the stress by time delay as an index. Based on the ship handling simulator experiment, it is verified that difficulty of navigation changes is highly correlated with the time delay, which result from compensation actions of slowdown engine and altering course.

• Science of Emotion and Sensibility
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• v.3 no.1
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• pp.7-16
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• 2000

본 연구에서는 화상 시뮬레이터 상에서 저속 (40km/h) 주행과 고속 (160km/h) 주행으로 지루감 및 긴장감을 유발시킨 후, 100%의 Jasmine abs와 Lavender oil france (KIMEX Co. Ltd)의 향 자극이 지루함 및 긴장감의 증감에 미치는 영향을 알아보고자 한다. 건강과 피험자 10명을 대상으로 심전도, 피부온도, 맥파의 자율신경계 반응을 측정하였다. 또한 각 실험 전후에 Simulator Sickness를 측정하여 Simulator Sickness가 실험 결과에 미치는 영향을 분석하였다. 지루한 저속 주행 시 향자극이 없을 때에 비해 각 향을 제시하였을 때 각성 효과가 발생하여 교감 신경계가 활성화됨을 자율신경계 반응으로 관찰할 수 있었다. 그러나 두 가지 향에 따라 큰 차이는 발생하지 않았다. 본 연구로부터 일정하고 느린 주행으로 유발되는 신체의 이완 현상 또는 졸리움 현상이 향 자극에 의해 감소되는 경향을 자율 신경계의 반응을 통해 관찰할 수 있었다. 고속 주행 시에는 향을 제시하지 않았을 때보다 두 가지 향을 제시하였을 때 긴장감이 모두 이완되는 경향을 나타내었다. 따라서 고속 주행으로 유발되는 신체의 긴장감이 향 자극으로 인해 감소된다는 사실을 자율신경계의 반응을 통해 관찰할 수 있었다. 그러므로 본 연구로부터 지루한 저속 주행으로 유발된 신체의 이완감과 고속 주행으로 유발된 신체의 긴장감은 각 향 자극에 의해 이완감의 감소와 긴장감의 감소를 유발하였다는 사실을 관찰할 수 있었고, 두 향의 차이는 관찰할 수 없었다.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.74-82
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• 2007

The M-Method that measures the speed of actuator with counting the number of Reaction wheel Tacho Pulse has the many advantages such that a realization is simple and measuring time is uniform, but it also has the disadvantage that measuring speed becomes worse as the wheel speed goes lower. On the contrary, the T-Method that measures the time duration between the pulses is more accurate at lower-speed and its time delay is smaller than M-Method, but its realization is more difficult than M-Method because measuring time is varying with wheel speed variation. Thought M/T Method mixing M-Method with T-Method is widely used in order to measure the speed in the motor industrial area, one of two methods has been used in the spacecraft design area. Therefore, we try to apply both methods together to measuring the speed of Reaction Wheel, the core actuator for low earth orbit satellite. This paper provides the Reaction Wheel simulation board located in the Spacecraft Dynamic Simulator, ground support test set.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.137-142
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• 2001

The traditional schedule management system provides project manager with analysis reports, such as progress control, earned value management and resource management, including schedule chart. However, the reports and functions in the traditional system are still limited in 2D concept. Recently, the scheduling method is using 4D concept that time of construction schedule is linked to space of drawings. This study presents the limitation of those systems and an improved method for developing 4D system through the comparative analysis of representative 4D systems that are developed up to date.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.129-134
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• 2012

In this paper, speed control of IPMSM drives for the next generation domestic high speed railway system using NPC 3-level inverters is presented. The NPC multilevel inverter is suitable for the high-voltage and high-power motor drive system because it has advantages in that the voltage rating of the power semiconductor devices and output current harmonics are reduced. For the speed control of IPMSM using NPC 3-level inverters, maximum torque control is applied in the constant torque region, and filed weakening control is applied in the constant power region. Simulation programs based on MATLAB/Simulink are developed. Finally the designed system is verified and their characteristics are analyzed by the simulation results.

• The KIPS Transactions:PartC
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• v.18C no.4
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• pp.279-286
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• 2011

This paper proposes techniques for wireless sensor network routing algorithm with small routing traffics. It reduces routing traffic by gathering routing messages for fixed duration of time and the routing message for the configuration result is sent once. The routing traffic gathering technique has disadvantage of longer network configuration time. To overcome this, first one or first few routing messages are delivered immediately and later routing messages are gathered for fixed duration of time. The proposed scheme was modelled and implemented in Qualnet simulator using C language. Experimental results show that the proposed techniques are effective for reducing routing traffics.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.181-192
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• 2010

We develop a dispatching policy for stochastic scheduling simulation especially for a continuous manufacturing system with machine breakdowns. The proposed dispatching policy computes an urgency index with the consideration of re-heating, setup cost and remaining due date. Prioritized by the index, we execute swapping or reassigning material sequences so as to minimize the total penalty cost. To evaluate the performance of the proposed policy, a discrete event simulation is developed. With 200 data sets and 20 iterations, we compare the performance of the urgency policy with those of SPT (Shortest Processing Time) and FCFS (First Come First Serve) which are the most common policies. The result shows that the proposed policy consistently gives the lowest total costs by reducing the penalty costs for lateness.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.97-103
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• 2015

This paper has focused on the middle term process planning around quays based on the prefixed long-term plan of the product mixed ships. Recently, the order rate of high add-value ships in domestic shipyards has been sharply increased and the spending time at quays is accordingly on an increasing trend. For proper and practical process planning related to quays, it has to be closely connected with a long-term plan and product calendar, erection network and result of ship allocation around quays. Moreover, it is also required to include the integrated consideration of the whole process of a yard, each ship, and each team respectively. The most distinguishing feature of this study is that it would run on the ship allocation simulator and GIS framework in order not to be limited to the specific one yard and the readers can figure out the optimization formulation containing the work load leveling and a different approach from PERT/CPM. The proposed approach reflected all requirements from the department of process planning and management in a shipyard, and the analysis of the results has explained its performance of the optimization result with the examples of total 43 ships under construction from 2008 to 2013.