• Proceedings of the KWS Conference
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• 2010.05a
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• pp.28-28
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• 2010

The secondary barrier of cargo containment for membrane LNG tank is composed of composite materials such as rigid triplex (rigid secondary barrier, RSB) and flexible triplex (flexible secondary barrier, FSB). RSB and FSB are adhered to each other using an epoxy adherent and the quality of the secondary barrier depends on the bonding strength between them. The bonding strength between RSB and FSB is greatly influenced by the surface condition of RSB prior to joining. In this study, the effect of surface condition prior to joining on the joint strength and the fracture mode occurred between RSB and FSB have been examined in order to establish a proper surface treatment method for improving the bonding strength at the temperature of $-170^{\circ}C$.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.397-409
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• 2021

This study proposes a new approach to implimentation of robust control and torque control response analysis based on monitoring simulator for smart factory. According to the physical properties of a flexible manipulator, a two time-scale approach, namely, singular perturbation ap proach, is further utilized for thorough analysis and general controller design. It is shown that asymptotic motional tracking can be effectively achieved, whereas the force regulation errors can be made arbitrarily small. For demonstration of the proposed technology performance, experiments of a eight joint flexible manipulator are performed for the proposed control method, and the reliability of proposed control results are illustrated based on monitoring simulator.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.5015-5038
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• 2018

In this paper, a novel spectral-spatial joint sparse representation algorithm for hyperspectral image classification is proposed based on multi-layer superpixels in various scales. Superpixels of various scales can provide complete yet redundant correlated information of the class attribute for test pixels. Therefore, we design a joint sparse model for a test pixel by sampling similar pixels from its corresponding superpixels combinations. Firstly, multi-layer superpixels are extracted on the false color image of the HSI data by principal components analysis model. Secondly, a group of discriminative sampling pixels are exploited as reconstruction matrix of test pixel which can be jointly represented by the structured dictionary and recovered sparse coefficients. Thirdly, the orthogonal matching pursuit strategy is employed for estimating sparse vector for the test pixel. In each iteration, the approximation can be computed from the dictionary and corresponding sparse vector. Finally, the class label of test pixel can be directly determined with minimum reconstruction error between the reconstruction matrix and its approximation. The advantages of this algorithm lie in the development of complete neighborhood and homogeneous pixels to share a common sparsity pattern, and it is able to achieve more flexible joint sparse coding of spectral-spatial information. Experimental results on three real hyperspectral datasets show that the proposed joint sparse model can achieve better performance than a series of excellent sparse classification methods and superpixels-based classification methods.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.75-83
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• 2008

The purpose of this study was to evaluate the correlation between joint moment and joint position angle according to the different walking speeds. According to the different walking speeds(1.5m/s, 1.8m/s, 2.1m/s), experiments were terminated by 8 male subjects. In conclusion, 1. The peak extensor moment of knee joint increased by increasing walking speed, however, walking speed didn't have an effect on peak flexor and abductor moment of knee joint. 2. The position angle of knee joint increased movement of flexion, but other position angles of knee joint didn't have difference when the peak extensor moment generated. 3. The peak joint moment of hip significantly increased in extension, flexion and abduction by increased walking speed. 4. The hip position angle showed more flexible at the hip peak flexor/extensor moment generated. 5. The co-ordination pattern between peak knee joint moment and knee position angle were mathematically modeled by using a least square method. We could get the high level value of R2. We expect to apply this results for evaluating the physical faculty of knee joint.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.45-48
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• 2001

Unequal Error Protection(UP) is reasonable scheme in transmission of compressed video with low bit rate. Because it offers the error correction ability each other data according to the Source Significance Information. Hence it can also be flexible to the given channel environment on the video transmission. This paper propose the joint source channel coding through the UEP in consideration of the hierarchical structure of H.263+ based video and the influence of the transmission error. It especially proposes the error-resilient video transmission technique which can reduce complexity of channel coder & decoder by partitioning the video data with a frame. As the result of the proposed algorithm, it is possible to increase the quality of reconstructed video in the error environment without creating additional bits.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.270-278
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• 1996

복잡한 비선형성과 불확실한 변수를 가지는 유연 죠인트 로봇의 견실한 관측기 설계에 관한 연구이다. 시간 불변 또는 시간 가변성의 불확실한 변수들을 가지는 시스템에 적용한 경우이며 로봇 링크의 각도와 각속도들을 출력으로 하였다.본 견실 관측기는 리아프노프 방법에 기초를 두었으며 불확실한 변수들은 그값을 모르나 그 값들은 지정된 집합내에 존재한다. 제안된 견실 관측기는 실용적인 안정성을 보장한다. 관측기설계의 알고리즘을 2링크 유연 죠인트 로봇에 적용하여 시뮬레이션을 수행하여 우수한 성능을 가짐을 확인할수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.507-512
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• 1997

This paper presents a method of finding optitnal joint torques of two robots when they hold an object simultaneously. Although the importance of the multiple cooperating robot system increases for more flcviblc ni;mufacturing automation, dynamic solutions to multi-robot system forming closcd kinematic chain is not easy to find. Newton-Eulcr approach is used for the dynamic formulation of two robots fonn~ng closcd kincmatic chains gmsping a rigid body object. The nrcthodology to optimize the joint torques to satisfy given criterta and obtain bettcr control of the system is discussed. The scheme is illustrated by an example.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.171-176
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• 2001

Recent building structures are superior in its ability but they are light and flexible, and so have problems of vibration. In general, the problem of vertical vibration is not considered in structural design. However, in terms of serviceability for inhabitants in buildings, the estimation of vibration in design stage is important. Characteristics of vertical vibration is changed by modeling method of beam-column joint. To check the characteristics of vertical vibration, many tests and analyses were conducted on constructing building in Seoul. Results of tests and analyses were compared using transfer function. As a results, to check the vertical vibration, the cramp ratio of beam-column joint must be considered and reduced in structural design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.95-102
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• 1997

Jointless bridge is a new construction method applicable to bridge of short length. In the jointless bridge expansion of superstructure due to thermal effect was absorbed in the flexible pile-type abutment in stead of expansion joint in the conventional bridges. By removing expansion joint, it retards deterioration and extends life time of bridge. In this paper, jointless bridge of steel box girder type was studied through finite element analysis. Stress variations of superstructure and pile due to thermal effect was studied for the two span continuous integral bridge of 80m length and the results of analysis was presented.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.638-647
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• 1996

Robot manipulators for harvesting fruits must be controlled to track the desired path of end-effector to avoid obstacles under the consideration of collision free area and safety path. This paper presents a robot path control algorithm to secure a collision free area with the recognition of work environments. The flexible space, which does not damage fruits or branches of tree due to their flexibility and physical properties , extends the workspace. Now the task is to control robot path in the extended workspace with the consideration of collision avoidance and velocity limitation at the time of collision concurrently. The feasibility and effectiveness of the new algorithm for redundant manipulators were tested through simulations of a redundant manipulator for different joint velocities.