• Journal of Yeungnam Medical Science
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• v.9 no.1
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• pp.167-174
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• 1992

Microvascular tissue transfers have facilitated primary closure of various complex defects after radical ablation of head and neck cancers. From Oct 1991 to Feb 1992, we used forearm free flap in two patients and delto-pectoral flap in one patient who had preoperative irradiation for pharyngoesophageal reconstruction. The stricture and fistular formation were most troublesome complication in forearm free flap, so we designed as lazy S shape in distal flap margin to prevent circular contraction and longitudinal margin was deepithelized(5mm) and sutured double layer to withstand fistular formation and this can be considered useful in place of a free jejunal transfer.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.265-269
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• 2006

Anti-Roll Tanks, also called Sloshing Tanks, is a rather common and sometimes an efficient method of limiting the roll angles. The important parameters, when considering using anti-roll tanks, are positioning, size, duct area, flow control device etc. Measurement by the PIV(Particle Image Velocimetry) was conducted to investigate the flow characteristics around control damper and inlet area of duct for three kind of inclined angle $(\alpha=0^*,\;10^*\;and\;20^*)$. Flow behaviors such as instantaneous and time-mean velocity vectors are investigated. Furthermore, to reveal boundaries between flowing and stagnant zones and to extract velocity profiles at any selected sections of the lower duct for passive anti-rolling tanks system.

• Fire Science and Engineering
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• v.24 no.6
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• pp.76-81
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• 2010

For the safe handling of n-heptane, the explosion limit at $25^{\circ}C$, the temperature dependence of the explosion limits and the lower flash point were investigated. And AITs (auto-ignition temperatures) by ignition time delay for n-heptane were experimented. By using the literatures data, the lower and upper explosion limits of n-heptane recommended 1.0 Vol% and 7.0 Vol%, respectively. And the lower flash points of n-heptane recommended $-4^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for n-heptane and the experimental AIT of n-hexane was $225^{\circ}C$. The new equation for predicting the temperature dependence of the explosion limits of n-heptane is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.313-320
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• 2012

A hybrid floating structure system combined with pontoon and semi-submersible type modules is proposed. This new system can reduce tensile forces of bottom slabs which could cause fatal damage of concrete floating structures. We performed a parametric study on the dimensions of this new system and investigate the sensitivity of the parameters to the behavior. In order to investigate various cases efficiently, we developed a simple two-step static analysis method for the fluid-structure interaction. An optimum system is derived from the investigation of the analysis results, weights and drafts of the hybrid structure. This study shows that introducing this new system to concrete floating structures is an effective way to reduce the tensile force of the bottm slab of such a floating structure. Also, it was found that when the length of the semi-submersible module is about 15%, the behavior would be optimal in the considered case.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1265-1271
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• 2014

The lamp cooling system of the exposure has effect on the exposure efficiency and device lifetime. In this paper, we performed the numerical analysis about the thermal flow in the lamp housing of the exposure apparatus for the cooling air inflow rate. We set up the velocity of cooling air of side and bottom as the independent variables because cooling performance of the lamp housing is affected by the velocity of the cooling air side and bottom. The cooling state of lamp housing depend on three dependent variables; the temperature at top mirror and exhaust gas, ellipsoidal mirror. Response surface methodology was used in order to establish the efficient cooling analysis plan. The regression equation predicting the variables temperature of lamp housing according to the cooling air velocity were drawn. The velocity of cooling air to reach the optimum temperature of the lamp housing were derived.

• Tunnel and Underground Space
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• v.27 no.6
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• pp.406-421
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• 2017

This study describes a precise numerical analysis process by adopting the real image of mine openings obtained by LIDAR, which can produce a point cloud data by measuring the target surface numerically. Research area is a section of underground limestone mine which is used hybrid room-and-pillar method for improving the production rate. From the application of LIDAR to this section several results were deduced, that is, the central axis of upper and lower vertical safety pillars is distorted to the direction of NW and the section area of lower vertical safety pillar is $34m^2$ smaller than the designed area of $100m^2$. The results of precise measurement in geometrical shape of mine openings and precise simulation in numerical analysis confirms that LIDAR techniques can be suggested as a valuable tool for stability analysis in underground mine by configuring the mine opening shape.

• Fire Science and Engineering
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• v.13 no.1
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• pp.11-19
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• 1999

The flash point is generally used as a hazardous index of fire and explosion of a flammable liquid. A classification of the flash points is important for the safe handling of flammable liquids such as solvent mixtures. The flash points of pure substances and solvent mixtures can be c calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and a activity coefficient models. In this study, experimentally determined lower and upper flash points w were compared with the calculated values by using Raoult's law and van Laar equation. The flash points of pure substances were in agreement with the calculated values by vapor pressure and e explosive limits. Also, the lower flash points of M.E.K(methylethylketone)-toluene system were i in agreement with the predicted values by Raoult’s law, and the upper flash points were in a agreement with the predicted values by van Laar equation. By means of this methodology, it is possible to evaluate reliability of expermental data of the flash points of the flammable mixtures.

• Korean Journal of Bronchoesophagology
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• v.6 no.1
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• pp.7-15
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• 2000

Background and Objectives:Submucosal spread of hypopharyngeal canceris frequently incriminated for the high incidence of local recurrence after resection. Although mucosal spread is better detected by means of direct visualization, submucosal spread is better evaluated by using cross-sectional imaging rather than endoscopy. This study was designed to evaluate the efficacy of MRI in diagnosing involvement of inferior margin of hypopharyngeal cancer. Materials and Method : Eight patients with hypopharyngeal cancer underwent MRI prior to surgery. And postoperative histopathopogic involvement of tumor was compared with the preoperative MRI axial scan. Results : In preoperative MRI findings, involvement of pyriform sinus apex was 6 cases(definitive 5 cases, probable 1 cases), that of esophageal inlet was 1 case(probable), that of cervical esophagus was 1 case(probable). In postoperative histopathologic findings, the results were same. Conclusion : MRI evaluation for patient with hypopharyngeal cancer ensures accurate staging and provides essential information about the tumor involvement of inferior margin. And there is needed to be thin section thickness in evaluation of inferior margin of hypopharyngeal cancer.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.435-444
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• 2007

Caching web pages is an important part of web infrastructures. The effects of caching service are even more pronounced for wireless infrastructures due to their limited bandwidth. Medium to large-scale infrastructures deploy a cluster of servers to solve the scalability problem and hot spot problem inherent in caching. In this paper we present scheduling scheme based on cache utilization in a wireless internet proxy server cluster environment. The proposed method uses cache utilization for distributing evenly client requests to a cluster of cache servers and solving hot spot problem. We have implemented our approach and performed various experiments using publicly available traces. Experimental results on a cluster of 16 cache servers demonstrate that the proposed hashing method gives 45% to 114% Performance improvement over other widely used methods while addressing the hot spot problem.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.86-89
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• 2015

Formula acoustic characteristics of the room with a double layer, are compared through simulation and actual measurement. The rear area of the under- balcony speakers will cause a delay difference between the main speaker. In the mid / bass parts do not generate sufficient pressure is lowered and comb-Filtering phenomenon occurs significantly. The lower right area of the under- balcony speakers and speaker distance is the sound pressure of the under- balcony speakers to around 2 ~ 3m bigger than the main speakers and the sound image matches the pulpit is broken. Also, under area is more than 5 ~ 6m from the balcony outside speakers and causes differ by more than 10dB lower than the under- balcony speakers depending on the local laws of Translator wins Well, the main speaker at mid / high frequency sounds do not enter the sound pressure variations will drop by a significant. Appropriate arrangement and the output of the speaker according to the position under the balcony, and output of the main speakers are requested to minimize this problem sound. The proper sound design direction for the under- balcony speakers must be presented in order to improve the lower balcony area more pleasant acoustic environment.