• Proceedings of the KSR Conference
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• 2006.11b
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• pp.494-507
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• 2006

The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

• Structural Engineering and Mechanics
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• v.24 no.4
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• pp.447-461
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• 2006

Here, the axisymmetric free flexural vibrations and thermal stability behaviors of functionally graded spherical caps are investigated employing a three-noded axisymmetric curved shell element based on field consistency approach. The formulation is based on first-order shear deformation theory and it includes the in-plane and rotary inertia effects. The material properties are graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents of the material. The effective material properties are evaluated using homogenization method. A detailed numerical study is carried out to bring out the effects of shell geometries, power law index of functionally graded material and base radius-to-thickness on the vibrations and buckling characteristics of spherical shells.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.172-175
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• 2003

Thermomechanical behavior of Al-Mg-Si alloys have been studied to investigate the effect of microstructural features such as pre-existing substructure and distribution of particles on the deformation characteristics. The controlled compression tests have been carried out to get the basic information on how the alloy responds to temperature, strain amount and strain rate. Then hot forging of Al-Mg-Si alloys has been carried out and analyzed by the comparison with the compression tests. Microstructural features after forging have been discussed in terms of the thermomechanical response of Al-Mg-Si alloys. As already well mentioned, we have found that the deformation of Al-Mg-Si at the elevated temperature brought the recovered structure on most conditions. In a certain time, however, abnormally large grains have been found as a result of deformation assisted grain growth, which means that hot forging of Al-Mg-Si alloys could lead to a undesirable microstructural variation and the consequent mechanical properties such as fatigue strength.

• Journal of Chest Surgery
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• v.17 no.1
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• pp.82-88
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• 1984

Total 310 cases of spontaneous pneumothorax in 281 patients were analyzed to review the results of surgical treatment for this condition. Clinical data on the age & sex distribution, recurrence, etiologic conditions and on the other aspects of spontaneous neumothorax were summarized. The results of surgical management of spontaneous pneumothorax are followings; 205 out of 310 cases[66.1%] were cured by closed thoracostomies. 82 cases[26.5%] were cured by thoracotomy. The indications of thoracotomy were 1] persistent air leakage, 2] history of recurrences, 3] blebs or bullae on thoracoscopy, 4] associated parenchymal lesion, 5] pneumothorax caused by paragonimiasis. Other reasons of thoracotomy were bilateral pneumothorax and inadequate expansion due to chronicity. Excision of blebs or wedge resection was performed in most cases with good result. Lobectomy [9 case] or pneumonectomy [3 cases] was carried out depending on the pathological involvement of the lung. There was no operative death and only one case showed recurrent pneumothorax during follow-up after thoracotomy.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.723-729
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• 1987

A retrospective study of 21 cases of chest wall tumors, 12 benign and 9 malignant, was carried out to review their clinical radiological and pathological features. On age distribution, most cases [80.9%] were found in 4th to 6th decades. The sex ration [M:F] was represented as 2.5:1. Of the 21 lesions, there were 8 cases of soft tissue tumors, 4 cases of bone and cartilage origined tumors and 9 malignant tumors which included 3 metastatic tumors. The overall mortality was 22.2% and all of the deaths were found in the malignant tumors. All of the patients with benign tumors were treated by excision without recurrence. Distinction between benign and malignant chest wall tumors was not possible using radiographic criteria unless cortical destruction and involvement of soft tissue were visualized. On the basis of our analysis, we believe that all tumors of chest wall should be considered malignant until proven otherwise and that wide excision should be carried out. This is necessary not only to obtain as adequate diagnosis but also to provide the best chance for cure in both benign and malignant lesions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.71-74
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• 2001

The conventional tracking testing as IEC-60587 is widely used In surface aging measurement of outside insulator because those testing can carry out very short time in Lab testing. Also IEC-60587 testing is able to offer the standard judgement of relative degradation level of outside HV machine. Therefore it is very useful method compare to previous conventional tracking testing method and effective Lab testing method. But surface discharges(SD) have very complex characteristics of discharge pattern so it is required estimation research to development of precise analysis method. In recent, the study of IIR-camera is carrying out discover of temperature of power equipment through condition diagnosis and system development of degradation diagnosis. In this study, SD occurred from IEC-60587 is measured with partial temperature distribution in real time, the degradation grade of SD is analyzed through produced patterns in IEC-60587 according to applied time.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.7
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• pp.361-367
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• 2018

This study investigates the seismic performance of a hybrid seismic energy dissipation device composed of a viscoelastic damper and a steel slit damper connected in parallel. A moment-framed structure is designed without seismic load and is retrofitted with the hybrid dampers. The model structure is transformed into an equivalent simplified system to find out optimum story-wise damper distribution pattern using genetic algorithm. The effectiveness of the hybrid damper is investigated by fragility analysis of the structure with and without the dampers. The analysis results show that after seismic retrofit the probability of reaching damage states, especially the complete damage state, of the structure turn out to be significantly reduced.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.49-55
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• 2010

Many electric poles in the softground have been collapsed due to external load. In this study, 10 types of tests were performed with variation of location, numbers and depths of anchor blocks as well as depth of poles to find stresses acting on concrete electric poles. The stresses of concrete poles are relaxed at 600~700[kg] of tensile load, and stresses are concentrated at top of pole, and spread to lower part of pole. In the concrete pole collapse test, tensile load at failure was approximately 1,400[kg], which is twice of design load. As passive zone in the soil increases, the stresses acting on concrete pole are concentrated at lower part of pole based on moment arm earth pressure distribution.

• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.3-10
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• 2009

Domestic distribution market is in a time of transition for the present. With consumers' diverse demands, the growth of department stores, shopping malls, specialized shops and so on has been taken place radically and the competition among them also has become severe. In order to promptly and positively cope with the radically changing trend of market and the generation of competing business entities, they are necessary to establish a discriminated indoor space plan. With such desires as the expansion of leisure activities based on the increase of personal income and the up-gradation, diversification and individualization of living standard based on economic growth, the dining-out space, one of people's life environments, need a variety of changes. In the past, the specialized restaurants of composite shopping malls and department stores were a mere mediating space of food sale between producers and consumers, but today they become a discriminated and creative indoor space which representing customers' lifestyle. The purpose of this study was to examine the characteristic of public space of specialized restaurants at composite shopping malls and department stores and then present a discriminated spatial marketing strategy in order to find out the direction of its proceeding in the future. Therefore, the purpose of this study was to work out basic data for the development of dining-out contents at the time of appearing diverse composite dining-out spaces in the future and of establishing a renovation plan of specialized restaurants at composite shopping malls and department stores in order to provide customers a space which could satisfy their desires. In this vein, the characteristic and composition of necessary space was analyzed based on the examination of cases. The investigator hopes that study findings are used as basic data for the study on the interrelationship between the sale space and dining-out space of composite commercial facilities and for the establishment of marketing strategy to attract customers.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.281-282
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• 2003

Numerical investigations are carried out to study the mass flux and temperature distribution in a calandria using a 3-D RANS code. The computations made for simulations of flow and convective heat transfer with near-to working conditions. The work provides an estimate of the safe working limits of the heat dissipation by virtue of prediction of the 'hot spots' in the calandria. The work assumes significance for preliminary designs of the reactors and for detailed critical parametric analysis that would be otherwise more expensive.