• Bulletin of the Korean Mathematical Society
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• v.46 no.5
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• pp.931-940
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• 2009

Given a system of smooth 1-forms $\theta$ = ($\theta^1$,...,$\theta^s$) on a smooth manifold $M^m$, we give a necessary and sufficient condition for M to be foliated by integral manifolds of dimension n, n $\leq$ p := m - s, and construct an integrable supersystem ($\theta,\eta$) by finding additional 1-forms $\eta$ = ($\eta^1$,...,$\eta^{p-n}$). We also give a necessary and sufficient condition for M to be foliated by reduced submanifolds of dimension n, n $\geq$ p, and construct an integrable subsystem ($d\rho^1$,...,$d\rho^{m-n}$) by finding a system of first integrals $\rho=(\rho^1$,...,$\rho^{m-n})$. The special case n = p is the Frobenius theorem on involutivity.

• Journal of Chest Surgery
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• v.26 no.3
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• pp.204-208
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• 1993

The review of 68 patients, who were diagnosed as spontaneous pneumothorax during the period from Dec, 1991. to Jul, 1992. were performed thoracoscopy of 70 cases under local anesthesia with 1% lidocaine at the department of thoracic & cardiovascular surgery, HanYang University Hospital. Clinical data on distribution of Age & Sex, Location, Frequency of Reccurrence and other aspects of pneumothorax were summerized.37 cases were treated by thoracoscopic management and closed thoracostomy. As thoracoscopic management, Electrocauterization of bullae or blebs[37 cases], Endo-clip application [2 cases], Removal of foreign body[1 case] were performed. 31 cases were cured by open thoracotomy. The thoracotomy indications under thoracoscopic finding were followed as: 1. Severe pulmonary adhesion and destroyed lung parenchyme 2. multiple bullae or blebs on several areas 3. finding of pulmonary tuberculous caseous lesion 4. persistant air leakage after 7 days from thoracoscopic management Excision, wedge resection of bullae or blebs was performed in most cases [22 cases], 2 cases by median sternotomy and Segmentectomy of 7 cases were carried out depending on the pathologic change of lung.There was no operative mortality and Follow-up for all patients were showed good results.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.388-391
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• 2011

A lesion that is hyperintense on diffusion-weighted imaging (DWI) and hypointense on the apparent diffusion coefficient (ADC) map is a characteristic magnetic resonance imaging (MRI) finding in acute ischemic infarction. In some cases, however, these findings can persist for a few months after infarct onset. It is thought that these finding reflect the different evolution speeds of the infarcted tissue. We report a patient with a right middle cerebral artery territory infarction with persistent hyperintensity on DWI and hypointensity on the ADC map for over 8 months. To our knowledge, this is the most persistent case of hyperintensity lesion on DWI and the serial MRI images of this patient provide important information on the evolution of infarcted tissue.

• Korean Journal of Computational Design and Engineering
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• v.4 no.3
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• pp.190-199
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• 1999

Presented in this paper is an algorithm for finding all intersections among polygonal chains with an O((n+k)·log m) worst-case time complexity, where n is the number of lien segments in the polygonal chains, k is the number of intersections, and m is the number of monotone chains. The proposed algorithm is based on the sweep line algorithm. Unlike the previous polygonal-chain intersection algorithms that are designed to handle special only cases, such as convex polygons or C-oriented polygons, the proposed algorithm can handle arbitrarily shaped polygonal chains having self-intersections and singularities (tangential contact, multiple intersections). The algorithms has been implemented and applied to 1) testing simplicity of a polygon, 2) finding intersections among polygons and 3) offsetting planar point-sequence curves.

• International Commerce and Information Review
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• v.10 no.1
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• pp.259-277
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• 2008

This paper empirically analyzes the influence of export insurance on export promotion using panel data for the Korean case during the sample period from 2003 to 2006. We use the Korean export's share in trading partners' imports as a weight for the weighted least square (WLS) estimation to measure the effect of export insurance on the export promotion. Our main finding is that export insurance subsidy seems to enhance the export performance when the Korean export takes greater share in other countries' markets. On the other hand, under weaker monopoly power of the Korean export, export risk and trading partners' GDP growth rate has more influence on the export promotion rather than export insurance subsidy. Our finding implies that policy makers and practitioners should discern the Korean exports' monopoly power differential across trading countries for better performing export insuarnce policy.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.758-763
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• 2001

A concept called Allowable Load Set (ALS) is introduced and methods of finding its boundaries are developed. The resulting diagram allows an easy understanding of load and strength characteristics of a structure in relation to structural integrity under uncertain loading conditions. An allowable load diagram for an ALS visualizes the relation between a prescribed load and a degree of safety of the structure. During the application of the algorithms, critical areas of the structure are identified. A systematic method of finding the allowable load sets for multi-body mechanical systems is especially presented and applied to an excavator as a realistic case.

• Journal of Korean Foot and Ankle Society
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• v.7 no.1
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• pp.131-134
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• 2003

Most interdigital neuroma can be diagnosed clinically. But, diagnostic local injection method, sonography and magnetic resonance image(MRI) have been used as secondary tests for clinical confirmation or surgery. Recently, there have been active discussions on the method of interdigital neuroma diagnosis for which sonography or MRI is used. For finding out the location or the number of interdigital neuroma particularly in non-typical clinical manifestation or surgery, MRIs, which are exellent in tissue contrast, may be quite helpful. This case had an interdigital neuroma showing non-typical manifestation. MRIs were used for clinical diagnostic confirmation and finding out the location and the number of interdigital neuroma. Thus, the validity along with literary consideration is being reported.

• Journal of Engineering Education Research
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• v.18 no.3
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• pp.39-45
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• 2015

Many methods have been suggested for a creative problem solving approach. TRIZ approach is ranked top in its practical application because it is originated from the real patent analysis. This approach is assumed to be generic which can be applied to any types of problems regardless of problem type and its domain. The objective of this study is to propose a creative problem solving approach using TRIZ's contradiction analysis, then introduce a case study of applying this approach to a creative design coursework. Main topic covers a creative problem solving approach, a problem definition using TRIZ contradiction analysis, finding invention principles, and problem solving from the generic approach. For the course project, Roborobo tool is adopted to implement the design concept. This coursework helps students finding a general problem solving approach, and applying a generic solution for their specific problem domain.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.556-558
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• 1995

This paper presents a new simplified method for finding the multiple load flow solutions and through their solutions the voltage stability can be evaluated. Line flow($P_{ij}$, $Q_{ij}$) may be formulated with the second-order equations for $V_{i}^{2}$ in polar coordinates or two circle equations for $e_{i}$ and $f_{i}$ in rectangular coordinates. Based on this feature, multiple load flow solutions are calculated with simple works, results of multiple load flow solutions are used for sensitivity analysis of voltage stability. Also, in the case that reactive power sources is considered, method of evaluating the voltage stability is introduced. The proposed method was validated to 2-bus and IEEE 6-bus system.

• Tuberculosis and Respiratory Diseases
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• v.38 no.1
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• pp.83-87
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• 1991

Pulmonary sequestration is an uncommon comgenital disorder and any specific finding has not been reported in chest P-A for diagnosis. We experienced a case of pulmonary sequestraion with visible feeding vessel in chest PA which was well matched with aortic angiography. This finding may provide the clue for the diagnosis.