• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1133-1145
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• 2000

It is necessary to develop an efficient analysis method to identify the dynamic characteristics of a large mechanical structure and update its finite element model. That is because these processes need the huge computation of a large structure and iterative estimation due to the use of the first- order sensitivity. To efficiently carry out these processes, a new method, called the generalized free-interface mode sensitivity method, has been proposed in the authors' preceeding paper. This method is based on substructuring approach such as a free-interface method and a generalized synthesis algorithm. In this paper, the proposed method is applied to the model updating of a car body structure to verify its accuracy and reliability for a large mechanical structure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.979-983
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• 2001

We develop a new method of simultaneous optimization of trajectory and shape of redundant flexible manipulators for collision-free utilizing the B-spline function and a mathematical programming method We adopt an approximate flexible manipulator model which consists of rigid bar elements and spring elements. We use B-spline function for determining the approximate trajectory and the expressions of the outline of obstacles. The used total performance index consists of 2 performance indices. The first is the driving energy, and the second is the trajectory deviation which is caused by the approximate modeling for the flexible manipulator. We design optimal collision-free trajectory of flexible manipulators by searching optimum positions of the control points for B-spline approximation which minimize the performance index subject to constraint condition for collision-free. Some examinations through numerical examples show the effectiveness of the method

• Archives of Reconstructive Microsurgery
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• v.23 no.2
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• pp.45-50
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• 2014

Palmar soft tissue defects are best reconstructed using a replacement flap of proper size with adequate soft tissue stability for mechanical resistance as well as with protective sensation. Reconstructive approaches are dictated by injury mechanism, defect size and location, and the status of the wound bed and tendino-skeletal structure. While uninjured portions of the hand can be used as a source for local flaps, the use of free flaps allows for maximal access for selection of the most ideal replacement tissue for the defect to be restored as close to the initial state as possible. Here, we review the garden variety of free flaps used in reconstruction of palmar soft tissue defects.

• Journal of Chest Surgery
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• v.24 no.12
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• pp.1232-1237
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• 1991

The cervical esophageal stricture has various surgical modalities and difficulties in reconstruction. We had experienced a case of successful reconstruction of the cervical esophageal restenosis using the free jejunal graft, on 30 year old man had had esophageal stricture after ingestion of lye. He had undergone colon interposition[esophagocologastrostomy] with left colon feeding gastrostomy. But restenosis was occurred just above of the cervical esophagocolostomy site several times of balloon dilatation were failed. So, we decided to use of the free jejunal graft. The free jejunal graft was isolated about 15cm length with it`s vascular arcades. The graft was irrigated with the mixed solution as isotonic saline, heparin and papaverine chloride. The artery of graft was anastomosed to the branch of the external carotid artery in end to side with continuous sutures of the 8.0 Prolene. The vein of the graft was anastomosed to the branch of the anterior facial vein in end to end with continuous sutures of the 8.0 prolene. Postoperative course was uneventful and the patient was discharged after removal of the tracheostomy cannula and gastrostomy tube.

• Korean Journal of Pharmacognosy
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• v.1 no.2
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• pp.23-28
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• 1970

One of the indigeneous plants to this country, Syringa dilatata $N_{AKAI}$ (Oleaceae) is known in commerce as 'Ya-Jung-Hyang' (野丁香) and has been known to be of effect as bitter stomachics. Seasonal variations in the content of polyalcohols and free reducing sugars in leaves of this plant which contains syringin glycoside, mannitol and free reducing sugars etc. were studied. Application of chromotropic acid to formaldehyde which was obtained from polyalcohols and reducing sugars by treatment with periodic acid results in reddish violet coloration and the solution has absorption maximum at wave length $570m\;{\mu}$. By the use of ionic exchange resin chromatography, poyalcohols were separated from the above mixture. The content of polyalcohols of this plant was plentiful in the growing season while that of free reducing sugars was decreasing vice versa.

• Computational Structural Engineering
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• v.7 no.4
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• pp.151-158
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• 1994

The free vibrations of thermally buckled, simply supported, symmetrically laminated, rectangular, and quasi-isotropic plates are investigated. The nonlinear postbuckling analysis is performed by the finite element method based on the first order shear deformable plate theory with the use of von Karman type nonlinear strains and the Duhamel-Newman type constitutive law. The postbuckling solutions are used to obtain free vibration responses of buckled plates. Several numerical examples for quasi-isotropic laminated plates are considered. The effects of width-to-thickness ratios and aspect ratios on the free vibration characteristics of buckled plates are investigated.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.1
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• pp.1-7
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• 2014

We consider a human contact social network that has connections through cellphone addresses. To construct such a social network, we use real call records provided by a large carrier, and connect to each other if there exists a call record between any two cellphone users. Due to its huge amount of data, we down-sample it in a way that the smallest-degree nodes are removed, in turn, from the network. For a moderate size of the networks we show that the degree distribution of the network follows a power-law distribution via linear regression analysis, implying the so-called scale-free property. We finally suggest some alternative measures to analyze a social network.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.300-306
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• 2004

This paper is concerned with the application of perturbation method to the dynamic analysis of free-free beam. In general, the rigid-body motions and elastic vibrations are analyzed separately. However, the rigid-body motions cause vibrations and elastic vibrations also affect rigid-body motions in turn, which indicates that the rigid-body motions and elastic vibrations are coupled in nature. The resulting equations of motion are hybrid and nonlinear. We can discretize the equations of motion by means of admissible functions but still we have to cope with nonlinear equations. In this paper, we propose the use of .perturbation method to the coupled equations of motion. The resulting equations consist of zero-order equations of motion which depict the rigid-body motions and first-order equations of motion which depict the perturbed rigid-body motions and elastic vibrations. Numerical results show the efficacy of the proposed method.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.385-392
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• 2005

The restriction of the use of hazardous substances in electrical and electronic equipment legislation mandates the substitution of lead and other hazardous substances in electronics products by July 2006. Due to this legislative pressure, the electronics industry is moving to adoption of lead free solders. In this paper, we investigated a flux to restrict generating electrochemical migration in lead-free solder. The lead-free solders used in this study were Sn-0.7Cu-0.01P and Sn-3.0Ag-0.5Cu. To measure the resistance of electrochemical migration, the dew-cycle test and water drop test were adopted. As the result, now flux having high durable of electrochemical migration was developed.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.829-832
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• 2010

Wireless Sensor Networks have been proposed for several location-dependent applications. For such systems, the cost and limitations of the hardware on sensing nodes prevent the use of range-based localization schemes that depend on absolute point to point distance estimates. Because coarse accuracy is sufficient for most sensor network applications, solutions in range-free localization are being pursued as a cost-effective alternative to more expensive range-based approaches. In this paper, we proposed a modified DV-Hop (range-free localization) algorithm which reduces node's location error and cumulated distance error by minimizing localization error. Simulation results have verified the high estimation accuracy with our approach which outperforms the classical DV-Hop.