• Corrosion Science and Technology
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• 제11권3호
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• pp.71-76
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• 2012

Computational fluid dynamics (CFD) is nowadays a powerful and reliable tool for simulating different flow processes and temperature. CFD is used to analyze the various pot geometries and operative variables in 55% Al-Zn pot of CGL. In this research, different strip velocities were assumed and then shown the flow pattern in the pot that was similar in the different strip velocities. Temperature distribution in the pot depended on inductors and inlet strip temperature at the steady condition. Generation of dross particles and transport models were considered to describe dross particles evolution inside the pot. In order to observe dross influence by scrap location, dross particles were generated upon the sink roll. Floating time of dross particles is different by scraper locations above the sink roll.

• 한국산학기술학회논문지
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• 제9권3호
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• pp.702-709
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• 2008

본 논문에서는 개인화와 이동성을 결합하여 제공될 수 있는 유비쿼터스 위치 기반 서비스 기반의 u-마케팅 시스템 프로토타입을 개발하였다. u-마케팅 시스템은 기존 모바일 마케팅 시스템을 보다 더 효율적으로 지원하는 u-LBS 기반 기술을 활용한 u-마케팅 콜센터이다. 지금까지의 모바일 마케팅이 불특정 다수의 고객에게 일방적으로 홍보 내용을 전달하는 스팸 방식에 마케팅이었다면, u-마케팅 시스템은 u-LBS 기반 기술을 활용하여 이동통신사 가입 회원의 성별, 연령, 거주지, 직업과 그리고 휴대폰의 위치정보나 GPS를 통하여 가입자의 위치정보를 활용함으로써 회원사가 원하는 맞춤형 타겟 마케팅을 지원할 수 있는 위치기반의 유비쿼터스 마케팅 시스템이다.

• 대한토목학회논문집
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• 제32권6D호
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• pp.539-547
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• 2012

교통수단간 환승은 대중교통체계운영의 효율성 증대를 위해 반드시 필요한 것으로 무엇보다 중요한 것은 현실에 기초한 환승거점의 선정이라고 할 수 있다. 본 연구는 대중교통 이용자의 통행실태를 반영한 환승거점 입지선정 방향에 관한 연구로서 대구광역시를 대상으로 대중교통 이용객 1일 교통카드 사용내역 자료를 활용하여 환승통행패턴을 분석하고자 한다. 군집분석을 통해 이용객이 많은 정류소를 분류하고 환승통행량의 규모에 따라 그룹핑하여 판별분석을 실시하였다. 도출된 판별 함수를 이용하여 현재 시공 중인 대구시 도시철도 3호선의 환승통행량을 추정하고 환승센터 설치 가능지점을 제시하였다.

• 설비공학논문집
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• 제15권12호
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• pp.1078-1087
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• 2003

Kimchi refrigerator is a household electric appliance developed with the wholly domestic technology for maturing and keeping kimchi. However, the principle of keeping is not yet revealed obviously. This numerical study has been conducted to investigate the flow and heat transfer characteristics in a kimchi refrigerator. The effects of arrangement variation of a evaporation tube are examined. Also, the heat transfer characteristics through the insulation material are discussed in detail. The flow and temperature field was simulated using the commercial code of CFX-5.3. A natural convection flow is formed through about 5/6 region from the bottom within the keeping space and accordingly, the 90% region of kimchi containers satisfies the temperature requirement with 0$\pm$0.5$^{\circ}C$. The stagnant flow exists in the upper 1/6 region of the keeping space and accordingly, the stratified high temperature distributions appear in the upper region of kimchi containers. The upward shift of the start location of a evaporation tube improves the temperature concentration toward $0^{\circ}C$ but the pitch variation is of no effect. The heat fluxes on the insulation surfaces show two-dimensional distributions with being higher toward the center. Through the variation of insulation thickness, 3.5% saving of insulation material is obtained under the same heat transfer rate.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.474-478
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• 1992

The non-rational transfer function of a Bernoulli-Euler beam, as an important component of a flexible structure, is analyzed. The true pattern of zeros of that transfer function is investigated as a function of sensor and actuator seperation. Translational displacement sensors are used for two cases in which a force input and a moment input are seperately applied. When the displacement sensor is located at a certain point, the first pair of zeros on the real axis of the s-plane arrive at the origin and cancel the rigid-body mode. The location of the translational displacement sensors on the beamat which the rigid-body mode of the beam is unobservable is analyzed as the center of percussion and is uniquely located for each case. If sensor is moved beyond such a point, a pair of zeros appear on the imaginary axis and move away from the origin along the imaginary axis of the s-plane.

• 한국정보처리학회논문지
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• 제7권5S호
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• pp.1657-1665
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• 2000

Mobile agents based e-commerce system has many advantage than traditional e-commerce-information gathering on goods, price settlement and payment, delivery of the goods purchased, and so on. However, due to the security vulnerability that stems from mobile agent's mobility, mobile agents based e-commerce system has additional security problems. Therefore, in order to do e-commerce securely in th system, first of al the security issues on mobile agents must be addressed. It this paper, we propose a mobile agent transfer protocol that provides confidentiality and integrity of mobile agent in transit and mutual authentication for communicating hosts. We further show the security of the protocol against many possible attacks. Also, we suggest the location management mechanism of mobile agents based on the trust center. This mechanism is capable of finding their locations transparently and detecting mobile agent clones.

• Archives of Plastic Surgery
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• 제32권5호
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• pp.573-581
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• 2005

Breast cancer is the second leading cause of death in woman. Unfortunately, the frequency of breast cancer and mastectomy are increasing in Korea. This paper introduces the breast reconstruction by use of pectoralis major muscle transfer with breast implant for small size defect after skin sparing mastectomy for more satisfaction. We reviewed 24 consecutive patients who underwent breast reconstruction by pectoralis major muscle transfer with implant and only breast implant in Dong-A University from April 2002 to March 2004. The patient's age ranged between 29 and 54 years with mean of 42.3 years. We used pectorals major muscle transfer with breast implant in 12 patients and breast implant alone in 12 patients as control. The follow-up period of patients ranged from 10 months to 3 years with mean of 18.5 months. The points of comparison with control group reconstructed by breast implant alone were doctor and patient satisfaction score, operation time, duration of admission, amount of drainage, complication and satisfaction according to mass location. In conclusion, there is no difference with control group in the point of operation time, mount of drainage, duration of admission. And there is higher level of doctor's and patient's satisfaction in group reconstructed by pectoralis major muscle transfer with breast implant than implant only group. Especially, pectoralis major muscle transfer with breast implant was especially necessary for the defect in upper lateral quadrant of the breast to get more satisfaction. The advantage of pectoralis major muscle transfer with breast implant is prevention of the protruding and palpability of implant and aesthetically satisfactory result by intraoperative modification of breast shape.

• Nuclear Engineering and Technology
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• 제31권5호
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• pp.486-497
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• 1999

The local heat transfer coefficient is experimentally investigated for the reflux condensation in a countercurrent flow between the steam-air mixture and the condensate, A single vertical tube has a geometry which is a length of 2.4m, inner diameter of 16.56mm and outer diameter of 19.05mm and is made of stainless steel. Air is used as a noncondensible gas. The secondary side has a shape of annulus around vertical tube and the lost heat by primary condensation is transferred to the coolant water. The local temperatures are measured at 11 locations in the vertical direction and each location has 3 measurement points in the radial direction, which are installed at the tube center, at the outer wall and at the coolant side. In three different pressures, the 27 sets of data are obtained in the range of inlet steam flow rate 1.348∼3.282kg/hr, of inlet air mass fraction 11.8∼55.0%. The investigation of the flooding is preceded to find the upper limit of the reflux condensation. Onset of flooding is lower than that of Wallis' correlation. The local heat transfer coefficient increases as the increase of inlet steam flow rate and decreases as the increase of inlet air mass fraction. As an increase of the system pressure, the active condensing region is contracted and the heat transfer capability in this region is magnified. The empirical correlation is developed by 165 data of the local heat transfer. As a result, the Jacob number and film Reynolds number are dominant parameters to govern the local heat transfer coefficient. The rms error is 17.7% between the results by the experiment and by the correlation.

• 한국ITS학회 논문지
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• 제16권6호
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• pp.195-207
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• 2017

처음 스마트폰이 출시된 이후 다양한 모바일 디바이스들의 발전으로 모바일 트래픽의 사용이 폭발적으로 증가하고 있다. 특히 개인 방송, TV 콘텐츠를 지원하는 OTT(On-The-Top) 서비스가 발전하고 이를 이용하는 사용자가 많아질수록 높은 전송률을 요구하는 영상 트래픽이 증가하게 되어 망의 과부화가 발생할 수밖에 없다. 본 논문에서는 D2D(Device-to-Device) 통신과 위치기반 서비스를 이용하여, OTT 서비스 트래픽에서 발생하는 망 과부화를 해결할 수 있는 방안을 제시하였다. 무선통신망의 OTT 서비스 트래픽을 효과적으로 처리하기 위하여 기존 셀룰러 네트워크에 위치기반 서비스와 D2D 단말 관리를 수행할 수 있는 D2DS(D2D Server)와 LCS(Location Server) 기능블록을 추가하였다. D2DS와 LCS를 통해 OTT 서비스에서 콘텐츠 제공자나 수신자의 역할을 하는 사용자에게 위치기반 D2D를 제공할 수 있는 절차를 추가로 제안하였다.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2162-2173
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• 2021

In this paper, the coupling of fine-mesh computational fluid dynamics (CFD) thermal-hydraulics (TH) code and neutronics code is achieved using the Ansys Fluent User Defined Function (UDF) for code development, including parallel meshing mapping, data computation, and data transfer. Also, some CFD schemes are designed for mesh mapping and data transfer to guarantee physical conservation in the coupling computation. Because there is no rigorous research that gives robust guidance on the various CFD schemes that must be obtained before the fine-mesh coupling computation, this work presents a quantitative analysis of the CFD meshing and mapping schemes to improve the accuracy of the value and location of key physical prediction. Furthermore, the effect of the sub-pin scale coupling computation is also studied. It is observed that even the pin-resolved coupling computation can also create a large deviation in the maximum value and spatial locations, which also proves the significance of the research on mesh mapping and data transfer for CFD code in a coupling computation.