• Journal of Chest Surgery
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• v.44 no.4
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• pp.304-306
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• 2011

An azygos vein aneurysm is a very rare cause of a posterior mediastinal mass. Once the diagnosis has been confirmed, no treatment is usually required. However, the aneurysm can thrombose, and this may lead pulmonary thromboembolism, or the aneurysm may rupture. In these instances, the excision of the mass is recommended. Video-assisted thoracic surgery techniques have considerably improved. If it is necessary to remove the aneurysm, video-assisted thoracic surgery may be a good option for surgical treatment. We report a case of an aneurysm of the azygos arch that was successfully resected by video-assisted thoracic surgery.

• Korean Journal of Bronchoesophagology
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• v.17 no.2
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• pp.92-97
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• 2011

MMinimally invasive surgery (MIS) for early stage lung cancer has been an important treatment modality. However, the ergonomic discomfort and counterintuitive instruments hindered the application of video-assisted thoracic surgery (VATS) to more advanced procedures. To improve the compliance with MIS, robotic surgery was adopted. This advance aimed to alleviate the shortcomings of VATS by maximizing the comfort of the surgeon while providing instruments that enabled technically demanding operations and three-dimensional views with increased freedom for intrathoracic movement owing to EndoWrist$^{(R)}$. In this session, we introduced the clinical applications and its results of robot-assisted thoracic surgery in the field of lung cancer surgery. In conclusion, robot-assisted pulmonary resection with lymph node dissection for lung cancer is safe as well as feasible, and it results in a satisfying postoperative outcome. Robot-assisted surgery may provide a good alternative to conventional open or thoracoscopic surgery for lung cancer, provided that the cost effectiveness and long-term prognosis are confirmed.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.772-777
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• 2001

The gas-assisted injection molding process is often perceived to be unpredictable, because of the extreme sensitivity of the gas. Since a slight change in design or process parameters can significantly change the resulting gas penetration, few designers and molders have the level of experience with the new gas-assisted injection molding process required for the development of new parts. This paper is concerned with the unified molding for a thick cosmetic chest by using gas-assisted injection molding. CAE analysis was carried out to design the part and the gas channel without inducing sink marks. And based on the part weight measurement, the processing parameters to control gas penetration percentage were chosen through the method of design of experiments. A thick cosmetic chest was successfully produced using the gas assist technology. The sink mark issue associated with the conventional injection molded parts was resolved. Weight savings and cycle-time reduction were also achieved.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.203-206
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• 1996

Prediction of firm bankruptcy have been extensively studied in accounting, as all stockholders in a firm have a vested interest in monitoring its financial performance. The objective of this paper is to develop the hybrid models for bankruptcy prediction. The proposed hybrid models are two phase. Phase one are (a) DA-assisted neural network, (b) Logit-assisted neural network, and (c) Genetic-assisted neural network. And, phase two are (a) DA-assisted Case based reasoning, and (b) Genetic-assisted Case based reasoning. In the variables selection, We are focusing on three alternative methods - linear discriminant analysis, logit analysis and genetic algorithms - that can be used empirically select predictors for hybrid model in bankruptcy prediction. Empirical results using Korean medium-sized firms data show that hybrid models are very promising neural network models and case based reasoning for bankruptcy prediction in terms of predictive accuracy and adaptability.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.267-271
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• 2009

The aim of this study is to evaluate wavelength dependence for laser-assisted lipolysis using a mathematical simulation. In this study, a Monte Carlo simulation was performed to simulate light transport in fat and dermal tissue with 3 different laser wavelengths (${\lambda}\;=\;1064\;nm$, 1320 nm, and 1444 nm) that are currently used in clinic settings for laser-assisted lipolysis. The relative rates of heat generation versus penetration depth showed that the greatest amount of heat generation was seen in the tissues at ${\lambda}\;=\;1444\;nm$. This Monte Carlo simulation may help lend insight into the thermal events occurring inside the fat and dermal tissue during laser-assisted lipolysis.

• Transactions of Materials Processing
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• v.10 no.5
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• pp.402-410
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• 2001

The gas-assisted injection molding process is often perceived to be unpredictable, because of the extreme sensitivity of the gas. Since a slight change in design or process parameters can significantly change the resulting gas penetration, few designers and molders have the level of experience with the new gas-assisted injection molding process required for the development of new parts. This paper is concerned with the unified molding for a thick cosmetic chest by using gas-assisted injection molding. CAE analysis was carried out to design the part and the gas channel without inducing sink marks. And based on the part weight measurement, the processing parameters to control gas penetration percentage were chosen through the method of design of experiments. A thick cosmetic chest was successfully produced using the gas assist technology. The sink mark issue associated with the conventional injection molded parts was resolved. Weight savings and cycle-time reduction were also achieved.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.06a
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• pp.60-65
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• 2006

Previous studies demonstrated that laser ablation under transparent liquid can result in ablation enhacement and particle removal from the surface. In this work, the liquid-assisted excimer laser ablation process is examined fer polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), Si, and alumina with emphasis on ablation enhacement, surface topography, and debris formation. In the case of PET and PMMA, the effect of liquid is analyzed both fer thin water film and bulk water. As the ablation enhanement by liquid is already known for Si and alumina, the analysis focuses on surface topography and debris formation resulting from the liquid-assisted laser ablation process. The results show that application of liquid increases the ablation rate of PMMA while that of PET remains unchanged even in the liquid-assisted process. It is also revealed that the liquid can significantly improve the surface quality by reducing the debris deposition. However, the surface roughness is generally deteriorated in the liquid-assisted process. The surface toporaphy is found to be strongly dependent on the method of liquid application, i.e., thin film or bulk liquid.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.8
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• pp.629-634
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• 2016

Laser-assisted machining (LAM) is one of the most effective methods of processing difficult-to-cut materials, such as titanium alloys and various ceramics. However, it is associated with problems such as the inability of the laser heat source to generate an appropriate preheating temperature. To solve the problem, thermally assisted machining with multiple heat sources is proposed. In this study, thermal analysis of multiple heat sources by laser and arc is performed according to power, heat source size, and leading heat source position. Then, the results are analyzed according to each condition. The results of this analysis can be used as a reference to predict preheating temperature in thermally assisted machining with multiple heat sources.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.127-134
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• 2009

Laser-assisted machining uses primarily laser power to heat the local area before the material is removed. It not only efficiently reduces the cutting force during the manufacturing process but also improves the machining characteristics and accuracy with regard to difficult-to-machine materials. The prediction of relative deformations between the cutting tool and workpiece is important to improve the accuracy of machined components. This paper presents the deformation errors caused for a cylindrical workpiece by thermal effects in the laser-assisted machine tool using finite element method. The results can be used to increase the cutting accuracy by compensating thermal distortion prior to laser-assisted machining.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.131-134
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• 2005

This paper presents a computer-aided simulation and robotic-assisted execution technology of external fixation method to achieve fracture reduction and deformity correction in long bones. Combining the kinematic analysis with a graphic model of the tibia and the fixator allowed 3D simulation and visualization of the adjustments required to reduce fracture or correct bone deformity as a pre-operative planning tool. The developed robot model provided accurate deformity correction with small residual deformity based on the results of the planning. By incorporating the robot model with image-guided system and computer-aided planning, the integrated system could be useful for computer-aided pre-operative planning and robotic-assisted execution in fracture treatment and bone deformity surgery.