• Tunnel and Underground Space
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• v.16 no.6 s.65
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• pp.437-450
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• 2006

Failure around an underground opening is a function of in-situ stress magnitudes, intact rock strength and the distribution of fractures in the rock mass. At high in-situ stress, the failure process is affected and eventually dominated by stress-induced fractures preferentially growing parallel to the excavation boundary. This fracturing is often observed in brittle type of failure such as slabbing or spatting. Recent studies dies on the stress-induced damage of rock revealed its importance especially in a highly stressed regime. As the constructions of underground structures at deep depths increased, the cases of the brittle failure also increased and furthermore spalling was occurred in Korea at low depths. To improve the stability of the underground structures at highly stressed regime, the characteristics of brittle failure should be examined, but they have not yet been properly investigated. Therefore in this report the characteristics of brittle failure such as types, failure mechanism and modeling methods etc. were considered in all aspects, based on the previous researches.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.4
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• pp.175-184
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• 1997

The Seokdae Waste Landfill is a middle-sized site used from June, 1987 to May, 1993. Many joints and faults are developed in andesitic rocks and rhyolitic rocks distributed at the landfill. The chemical analyses of leachates, streams and groundwaters sampled in July, 1996 and June, 1997 show that the concentrations of leachates and streams were decreased, and that the groundwater qualities became worse. The groundwater contamination is deeply extended to not only shallow groundwater but also bedrock-groundwater around the Seokdae Waste Landfill Area. The range of groundwater contamination by the leachates is about 500 m to the west and about 1 km to the south from the boundaries of the waste landfill. The development of monitoring wells and pumping wells, the construction of a leachate-treatment facilities, and the adjustment of the existing grout curtains are necessary for the control of water pollution at the Seokdae Waste Landfill Area.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.568-572
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• 2002

We present a case of a 47-year-old woman with benign solitary fibrous tumor of the pleura originated in the diaphragm which was discovered incidentally on a chest radiograph. Chest radiograph, sonograph, computed tomographic scan and magnetic resonance image studies proved a well circumscribed and lobulated fibrous tumor of the pleura. During the subsequent right thoracotomy, the tumor was found to be encapsulated and consisted of firm mass. It was connected to the diaphragm with $5{\times}4$cm area by pedicle. Most of the tumor was free of adhesion. It was excised completely together with attached diaphragm. The tumor measured $23.5{\times}13.5{\times}8.0$cm and the pathologic diagnosis was benign solitary fibrous tumor and the attached diaphragm was free of disease.

• Investigative Magnetic Resonance Imaging
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• v.17 no.1
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• pp.41-46
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• 2013

We represent a pathologically proven case of a four-year-old male patient with renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion, which is rare but more frequent in children or young adults. Computed tomography showed about 2.5 cm size ill-defined mass in the right kidney. The mass was hyperechoic on ultrasound. Magnetic resonance imaging demonstrated a mass with capsular enhancement and diffusion restriction. We present a case of Xp11.2 renal cell carcinoma and provide review of the literature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.883-889
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• 2005

Error backpropagation algorithm of multilayer perceptron may result in local-minima because of the insufficient nodes in the hidden layer, inadequate momentum set-up, and initial weights. In this paper, we proposed the ART-1 based fuzzy supervised learning algorithm which is composed of ART-1 and fuzzy single layer supervised learning algorithm. The Proposed fuzzy supervised learning algorithm using self-generation method applied not only ART-1 to creation of nodes from the input layer to the hidden layer, but also the winer-take-all method, modifying stored patterns according to specific patterns. to adjustment of weights. We have applied the proposed learning method to the problem of recognizing a resident registration number in resident cards. Our experimental result showed that the possibility of local-minima was decreased and the teaming speed and the paralysis were improved more than the conventional error backpropagation algorithm.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.32-42
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• 2007

Severe damage can occur around deposition holes due to complex interaction of thermo-hydro-mechanical (THM) loading during the long term operation of high level radioactive waste repository. Many candidate sites for repository are located in crystalline rock mass, therefore mechanism of damage follows the form of brittle fracture and failure. This paper briefly introduces major outcomes from 15 years international collaborative project, DECOVALEX, and presents major study results for current ongoing benchmark test study from DECOVALEX-THMC, to evaluate the effect of THM loading to rock mass in excavation damaged zone (EDZ) near deposition holes. Through benchmark test model by simplifying THM loading to boundary loading obtained numerical results are compared, and discrete fracture interaction after up to 1 million years operation is discussed.

• Journal of Chest Surgery
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• v.39 no.2 s.259
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• pp.162-165
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• 2006

The innominate artery aneurysm is an uncommon entity. A 36-year-old man was transferred to our hospital because of incidental finding of right superior mediastinal mass. He had a history of blunt chest trauma due to automobile accident 16 years earlier. Computed tomography scanning demonstrated 5-cm sized sacular aneurysm with thrombus at the innominate artery. The prosthetic bifurcated bypass grafting from the ascending aorta to the right common carotid artery and right subclavian artery was performed under the moderate hypothermic cardioplumonary bypass. We report a successful surgical treatment for a rare case of the innominate artery aneurysm.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.616-618
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• 2009

A 5-year-old Pekinese dog was presented for evaluation of a back mass of 1 year duration. Fine needle aspiration cytology of the mass revealed numerous keratinocytes, and a lesser number of multinucleated giant cells along with a low number of spindle cells, which were suggestive of epidermal cyst or hair follicle tumor with secondary granulomatous inflammation. The mass was surgically removed and examined histologically. Microscopically there was partially encapsulated well-demarcated nodule in deep dermis and subcutis. The nodule consisted of central cyst and secondary cysts that were lined by a single or multiple layers of basaloid cells and squamous epitheliums with central laminated keratin. Multifocal aggregation of numerous macrophages and multinucleated giant cells were present. The final diagnosis was keratoacanthoma with granulomatous inflammation. The mass did not recur 5 months after surgery.

• Journal of Chest Surgery
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• v.40 no.8
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• pp.590-592
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• 2007

A 55-year-old male presented with intermittent cough and blood-tinged sputum. 35 years earlier in the Army Armed Forces, he had undergone lung surgery of the right upper lobe because of tuberculosis. Chest CT showed a mass-like lesion with an internal air-meniscus sign in the right lung. The mass was $5{\times}7\;cm$ in the right upper lobe and it was a well marginated lesion. The resected mass contained a foreign body, that is, a retained surgical gauge. Herein we report on a rare case of retained gauze after surgery that mimicked aspergilloma.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.349-358
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• 2010

For imaging complex subsurface structures such as salt dome, faults, thrust belt, and folds, seismic prestack reverse-time migration in depth domain is widely used, which is performed by the cross-correlation of shot-domain wavefield extrapolation with receiver-domain wavefield extrapolation. We apply the prestack reverse-time migration, which had been developed at KIGAM, to the seismic field data set of Block 5 in Jeju basin of Korea continental shelf in order to improve subsurface syncline stratigraphy image of the deep structures under the shot point 8km at the surface. We performed basic data processing for improving S/N ratio in the shot gathers, and constructed a velocity model from stack velocity which was calculated by the iterative velocity spectrum. The syncline structure of the stack image appears as disconnected interfaces due to the diffractions, but the result of the prestack migration shows that the syncline image is improved as seismic energy is concentrated on the geological interfaces.