• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.881-888
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• 2020

In this paper, research on estimation of states of a target of interest using Line Of Sight(LOS) angle measurement is performed. Target's position, velocity, and acceleration are chosen to be the states of interests. The LOS measurement is known to be highly non-linear, making target dynamic modeling hard to be implemented into a filter. To solve this issue, the Pseudomeasurement equation was applied to the LOS measurement equation. With the help of this equation, 3D variable turn target dynamic model is applied to the filter model. For better performance, Kinematic Constraint is also implemented into the filter model. As for the filter, Bias Compensation Pseudomeasurement Filter (BCPMF) is used which is known for its robustness to initial conditions. Moreover, Two-Stage Kalman Filter (TSKF) form was also implemented to benefit from the parallel computation. As a result, TBCPMF 3DVT-KC is proposed and simulated to assess performance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.429-437
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• 2009

This study addresses the optimal shape of a LCVA maximizing its vibration control effect through numerical parametric study. Various LCVAs having the same total mass and tuning frequency are designed with constraints on the dimensions and water level, and one obtaining the highest equivalent damping ratio of the controlled system is chosen as an optimal solution. As a result, it was found that the limit on the variation of the water level in the vertical liquid column plays an important role constraining the shape of the LCVA. As the LCVA width perpendicular to the plane of liquid motion increases, the equivalent damping ratio rises with slowdown so that determination of the proper width is important in design of the LCVA shape.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2050-2058
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• 2000

A method for the inverse dynamic analysis of constrained multibody systems considering friction forces acting on kinematic joints is presented in this paper. The stiction and the sliding which represent zero and non-zero relative motions are considered during the inverse dynamic analysis. Actuating forces to control the position or the orientation of constrained multibody systems are usually calculated in the inverse dynamic analysis. An iterative procedure need to be employed to calculate the actuating forces when the friction is considered. Furthermore, the actuating forces are not uniquely determined during the stiction. These difficulties are resolved by the method presented in this paper.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.70-74
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• 2001

In this paper, we studied the maneuvering performances of a ship with flapped rudder. PMM tests were carried out for a ship model with horn type rudder or flapped rudder. The Abkowitz's model was used as a basic mathematical model to simulate the maneuvering motions. The maneuvering motions of a ship with flapped rudder were compared with those of a ship with horn-type rudder. As a result, it was found that the turning ability of a ship with flapped rudder was remarkably improved.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.4
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• pp.282-290
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• 2015

In this study, a latching control technology, proposed by Sheng et al.(2015), was applied in order to maximize the extraction efficiency of WEC (Wave Energy Converter), which is the heaving buoy coupled with linear electric generator. The latching control is the phase-control technique for improving the wave energy conversion with appropriate latching duration of keeping the buoy fixed. From the time-domain analysis in regular waves, the latching control technology can significantly improve the heave velocity and extracted power, even though the resonance condition is not satisfied. By using the latching control technology, the draft of buoy as well as the required PTO damping force can be significantly reduced along with increased extracted power, which is a big advantage in manufacturing the WEC.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.4
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• pp.128-134
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• 2014

In this paper, we propose a detection method of the leukocyte motions in a microvessel by using spatiotemporal image analysis. The leukocyte motions that adhere to blood vessel walls can be visualized to move along the blood vessel wall's contours in a sequence of images. In this proposal method, we use the constraint that the leukocytes move along the blood vessel wall's contours and detect the leukocyte motions by using the spatiotemporal image analysis method. The generated spatiotemporal image is processed by a special-purpose orientation-selective filter and then subsequent grouping processes are done. The subsequent grouping processes select and group the leukocyte trace segments among all the segments obtained by simple thresholding and skeletonizing operations. Experimental results show that the proposed method can stably detect the leukocyte motions even when multiple leukocyte traces intersect each other.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.399-415
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• 1999

임플랜트 보철 환자의 하악 운동에 관한 연구를 위해 완전 고정성 보철 치료를 한 8명의 환자와 상하악 총의치를 장착한 8명의 환자, 그리고 5명의 자연치아 피검자를 대상으로 Sirognathograph(Siemens, Benshiem, Germany)와 BioPAK program(BioResearch, Milwaukee, U.S.A.)으로 한계운동과 당근시편에 대한 편측 저작운동에 대한 검사를 시행하였다. 편측 저작 운동은 전두면에서의 저작운동의 높이와 폭, 전두면에서의 저작각도, 시상면에서의 절치기준점의 최대 이동거리, 시상면에서의 저작운동의 전후방 이동거리, 최대개구속도, 최대폐구속도의 기준점으로 각 저작주기의 성적을 평균처리 하여 다음과 같은 결론을 얻었다. 1. 전두면에서의 저작운동의 높이는 자연치, 총의치, 임플랜트 군간에 유의성있는 차이가 없었다(p>0.05). 2. 전두면에서의 저작운동의 폭은 임플랜트 군이 자연치, 총의치 군에 비해 유의성있게 작은 수치를 보였다(p<0.05). 3. 전두면에서의 저작각도 분석시 임플랜트 군과 자연치 군, 임플랜트 군과 총의치 군간에 유의성있는 차이가 없었다(p>0.05). 4. 시상면에서의 절치기준점의 최대 이동거리 분석시 임플랜트 군과 자연치 군, 임플랜트 군과 총의치군간에 유의성 있는 차이가 없었다(p>0.05). 5. 시상면에서의 전후방이동거리는 자연치 군이 임플랜트 군, 총의치 군에 비해 유의성 있게 크게 나타났다(p<0.05). 6. 최대개구속도는 자연치 군이 총의치 군과 임플랜트 군에 비해 유의성 있게 작은 수치를 보였다(p<0.05). 7. 최대폐구속도는 각 군간에 유의성 있는 차이가 없었다(p>0.05). 8. 저작운동은 개인간의 차이가 커서 명확한 결론을 유추하기가 어려웠다.

• Journal of Oral Medicine and Pain
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• v.26 no.3
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• pp.181-187
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• 2001

스트레스가 인체의 항상성에 영향을 미쳐 다양한 질병 및 동통을 일으킬 수 있다는 것은 선학들의 연구에 의해 증명되어 왔다. 특히 정서적으로 중요한 구강안면영역에는 스트레스와 관련된 질병 및 동통이 많이 존재하는데, 이에대한 병리적 기전은 아직 뚜렷하게 밝혀져 있지 않다. 이에 저자는 스트레스와 말초 및 중추신경과의 병리적 관계를 알아보고자, 구속스트레스하에서 구강안면영역의 감각과 운동에 중요한 역할을 하는 삼차신경의 집합체인 삼차신경절과 뇌간조직의 단백질 변화를 western blot을 통해 살펴보았다. 실험동물은 생후 8주된 Sprague-Dawley계 웅성 백서 (323-367 g/bw)를 대조군 3마리, 실험군 15마리로 배정하였고 실험군은 실험 전기간에 걸쳐 구속스트레스를 부여하였다. 실험동물의 삼차신경절과 뇌간은 희생 즉시 적출되었으며, western blot을 시행하여 다음과 같은 결론을 얻었다. 1. 삼차신경절의 모든 군에서 약 18 KDa의 단백질이 균일하게 나타났다. 2. 뇌간의 모든 군에서 약 18 KDa 단백질이 발현되었으며, 정상 대조군, 실험 즉일, 1일, 3일, 7일에서는 뚜렷한 변화가 없었으나 실험 5일군에서는 현저한 감소를 보였다. 구속스트레스에 의해 뇌간의 5일군에서 약 18 KDa의 특수한 단백질이 뚜렷이 감소된 후 7일 군에서 다시 증가되었던 것은 스트레스에 의한 뇌간세포의 반응으로 생각되며, 뇌간에서와 다르게 삼차신경절에서는 그 변화가 나타나지 않았던 것은 스트레스에 대한 조직의 반응 차이라고 생각된다. 따라서 이를 명확하게 확인하기 위해서는 향후 수종의 스트레스와 관련된 단백질 변화에 대한 추가적인 연구가 필요하리라 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.306-311
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• 2017

This paper deals with the design optimization of the kinematic characteristics of an automotive suspension system. The kinematic characteristics of the suspension determine the attitude of the wheels, such as the toe and camber, which not only relates to tire wear during driving, but also greatly affects the control of the vehicle and its stability, which corresponds to the motion performance of the vehicle. Therefore, it is very important to determine the characteristics of the suspension mechanism at the initial stage of the design. In this study, a displacement analysis is performed to determine the kinematic properties of the suspension for the McPherson strut suspension. For this purpose, a set of constraint equations for the joints constituting the suspension mechanism was established and a program was developed to solve them. We also used ADS, a design optimization program, to obtain the desired kinematic characteristics of the suspension. As the design variables for optimization, we used the coordinates of the hard points, which are the points of attachment of the suspension to the vehicle body, and are defined as the summation of the toe-in for the up and down movement of the wheel as the objective function. As the constraint functions, the maximum camber angle and minimum roll center height, which are design requirements, are considered. As a result of this study, it was possible to determine the optimal locations of the hard points that satisfy both constraint functions and minimize the change of the toe-in.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.3
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• pp.296-303
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• 2014

This paper describes the simplified simulation method of the wire-guided underwater test body with natural supercavitation. In this paper, the simulation based model of the wire-guided underwater body with natural supercavitation is proposed by using preceding research and commercial flow-analysis software. By using the model, the 1-dimensional wire-guided body motion in natural supercavitation can be solved very fast with reliability. The suggested model is validated by the comparison of simulation results with experimental data.