• Structural Engineering and Mechanics
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• v.9 no.2
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• pp.195-208
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• 2000

To confirm the theory and static defect energy (SDE) equations proposed in the first part, extensive numerical simulation studies are performed in this portion. Stiffness method is applied to calculate the components of the stresses and strains from which the energy components and finally, the SDE are obtained. Examples are designed to cover almost all kinds of possibilities. Variables include structural type, material, cross-section, support constraint, loading type, magnitude and position. The SDE diagram is unique in the way of presenting damage information: two different energy constants are separated by a sharp vertical drop right at the damage location. Simulation results are successfully implemented for both methods in all the cases.

• 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 the Korean Society for Nondestructive Testing
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• v.29 no.3
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• pp.242-247
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• 2009

The ability of time reversal techniques to focus ultrasonic beams on the source location is important in many aspects of ultrasonic nondestructive evaluation. In this paper, we investigate the time reversal beam focusing of ultrasonic array sensors on a defect in layered media. Numerical modeling is performed using the commercially available software which employs a time domain finite difference method. Two different time reversal approaches are considered - the through transmission and the pulse-echo. Linear array sensors composed of N elements of line sources are used for signal reception/excitation, time reversal, and reemission in time reversal processes associated with the scattering source of a side-drilled hole located in the second layer of two layer structure. The simulation results demonstrate the time reversal focusing even with multiple reflections from the interface of layered structure. We examine the focusing resolution that is related to the propagation distance, the size of array sensor and the wavelength.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.268-273
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• 2004

This study is conducted to clarify the effect of internal pressure on the deformation and collapse behaviors of wall thinned elbow under in-plane bending moment. Thus the nonlinear three-dmensional finite element analyses were performed to obtain the moment-rotation curve of elbow contatining various wall thinning defects located at intrados and extrados under in-plane bending (closing and opening modes) with internal pressure of $0{\sim}15MPa.$ From the results of analysis, the effect of internal of collapse moment of elbow on the global deformation behavior of wall thinned elbow was discussed, and the dependence of collapse moment of elbow on the magnitude of internal pressure was investigated under different loading mode, defect location, and defect shape.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.59-63
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• 2010

This paper proposes computer visual inspection algorithms for various LCD defects which are found in a manufacturing process. Modular vision processing steps are required in order to detect different types of LCD defects. Those key modules include RGB filtering for pixel defects, gray-scale morphological processing and Hough transform for line defects, and adaptive threshold for spot defects. The proposed algorithms can give users detailed information on the type of defects in the LCD panel, the size of defect, and its location. The machine vision inspection system is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiment results show that the proposed algorithms are quite successful.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.255-263
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• 2009

Purpose: An osseous defect in the glenoid and humeral head is closely associated with recurrence of anterior shoulder instability. The purpose of this article is to describe the open surgical techniques and introduce our experiences with anterior instability with a significant osseous defect. Materials and Methods: We reviewed the articles that have focused on and/or mentioned the affect of osseous defects on anterior shoulder instability. The open surgical techniques and its related pearls are summarized in this review. Results: Accurate evaluation for the size and location of the osseous defect is critical for preventing recurrence after restoration of the anterior capsulolabral structure. The glenoid bone restoration techniques include the coracoids transfer (the Bristow procedure and the Latarjet procedure) and a structural iliac bone graft. Rotational humeral osteotomy and an osteoarticular allograft could be used for repairing a significant posterosuperior humeral defect (Hill-Sachs lesion). Shoulder arthroplasty may be tried for treating a humeral bone defect, but more study on this is needed. Conclusion: Open surgical restoration decreases the risk of recurrence anterior shoulder instability that is combined with a significant osseous defect. Arthroscopic surgery currently has limitations for treating an osseous defect, but it will become useful in proportion to the development of arthroscopic instruments and techniques in the future.

• Archives of Reconstructive Microsurgery
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• v.11 no.1
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• pp.29-35
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• 2002

Free flap reconstruction of the foot has become one of the standard procedures at the present time, but choice of a free flap for the soft tissue defect of the foot according to location and size remains controversial. We evaluated the results of free flap reconstruction for the soft tissue defects of the foot. Twenty seven free flaps to the foot were performed between May 1986 and December 2000 in the department of Orthopedic Surgery. Patient age ranged from 3 to 60 years. Male to female distribution was 20:7. Mean follow-up period was 30.5 months which ranged from 12 months to 60 months. The indications for a specific flap depended on the location and extension of the foot defect. In weight-bearing area and amputation stump, the authors chose the sensate (reinnervated) dorsalis pedis flaps (n=7) and sensate radial forearm flaps (n=2). In nonweight-bearing area including dorsum of the foot and area around Achilles tendon, we performed nonsensate (non-reinnervated) free flap reconstructions which included dorsalis pedis flaps (n=5), groin flap (n=1), radial forearm flaps (n=6), scapular flaps (n=4), latissimus dorsi flaps (n=2). Twenty-six flaps transferred successfully (96.3%). The sensate flaps which were performed in weight-bearing area and amputation stumps survived in all cases and recovered protective sensation. Mean two-point discrimination was 26 mm at the last follow up. As a conclusion, the selection of a proper flap depends on the location and extension of the foot defect and patient's age. Fasciocutaneous flap including radial forearm flaps and dorsalis pedis flaps were the best choice in nonweight-bearing area. The sensate free flaps which are performed in the weight-bearing area and amputation stumps can produce better outcome than nonsensate free flap.

• Journal of Korean Institute of Industrial Engineers
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• v.10 no.1
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• pp.11-16
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• 1984

An economic model is developed for determining optimal locations of screening inspection stations in a multistage production system. The effect of screening inspection on the production rate is explicitly considered, and a fixed cost for maintaining an inspection station is assumed. The product is allowed to have multiple defects, each of which may be inspected at any inspection station after the defect-generating operation. The problem is formulated as a mixed 0-1 linear program which offers the advantage of versatility in handling various system constraints.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.87-88
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• 2006

• Smart Structures and Systems
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• v.1 no.2
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• pp.121-140
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• 2005

This paper presents a systematic investigation of the effect of sensor location on the data quality and subsequently, on the effectiveness of machine health monitoring. Based on an analysis of the signal propagation process from the defect location to the sensor, numerical simulations using finite element modeling were conducted on a bearing test bed to determine the signal strength at several representative sensor locations. The results showed that placing sensors closely to the machine component being monitored is critical to achieving high signal-to-noise ratio, thus improving the data quality. Using millimeter-sized piezoceramic plates, the obtained results were evaluated experimentally. A comparison with a set of commercial vibration sensors verified the developed structural dynamics-based sensor placement strategy. It further demonstrated that the proposed shock wave-based sensing technique provided an effective alternative to vibration measurement, while requiring less space for sensor installation.