• Journal of the Korean Society of Combustion
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• v.20 no.3
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• pp.27-34
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• 2015

The objective of the current study is to introduce detailed process for a preliminary combustor design, and to develop a computer code for it. The program includes various empirical and semi-empirical methodologies for diffuser deign, combustor sizing, air distribution, and sub-component design such as primary and secondary zones. Using the developed program, the combustor sizing results are shown from an assumption of simple annual combustor cycle analysis. Two options are employed, 1) pressure loss approach, and 2) velocity assumption approach. Design results show that there are no significant differences in combustor sizing between two design options. Further code improvement is required for performance and emission evaluations of the designed combustor.

• Journal of the Korean Professional Engineers Association
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• v.34 no.4
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• pp.69-73
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• 2001

Due to the rapid increase of automobiles and daily driving distances, air pollution by automobiles is still dominant problem of large city in spite of strict emission refutation and development of reduction technologies. Among the air pollution resources of automobile , industry. electricity generation and heating. automobile keeps 51% of total nationwide air pollution in 1998 and this proportion Is increasing in large cities from 65% to 85%. To reduce these air pollution. catalytic converter and electronic engine control, exhaust gas re-circulation and evaporative emission control system have continuously developed and applied to automobiles since 1987. Also strong emission standards and emission durability warranty have enforced and monitored annually by sampling several vehicle models. But technologies and regulations are incomplete, driver should participate in reducing air pollution for himself by planning driving, avoiding unnecessary idle and air conditioning, keeping periodic maintenance and using mass transportation.

• Journal of Korean Society of Rural Planning
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• v.3 no.1
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• pp.96-104
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• 1997

The purpose of this study is to develop a dynamic DSS (Decision Support System) interfaced with GIS (Geographic Information System) and agriculture information network, In this study, DSS was developed to assist services which required tremendous and real time data in national scale. The data transmitte'd from the local area by the agriculture network were stored in DBMS (Data Base Management System) and analyzed by GIS. GIS and database tools used in this study were ARC/INFO 7.1.1 and INFORMIX 4.0. ACSAS (Agriculture Calamity Service Asist System) by the system prototype was constructed to solve the problem about the drought counterplan service which was to take the responsibility in the Ministry of Agriculture. It was easy to transfer, process, and analyze the information using the system. Specially, the meteological, the reservoir storage rate and the drought counterplan information were spatially analyzed by the functions of GIS.

• Korean Journal of Bronchoesophagology
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• v.5 no.2
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• pp.202-206
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• 1999

A carotid artery resection and replacement including neck dissection are used as a method of treatment for head and neck cancer with infiltration into the carotid artery. The recent development of imaging technique makes it easy to estimate the detailed anatomical relationship between the tumor infiltration into the carotid artery, it's resection and replacement are indicated at radical neck dissection. To detect any possibility of cerebral ischemia at the time of ligation of carotid artery, a temporary occlusion test of internal carotid artery with a ballon catheter (balloon occlusion test) is performed. Recently, we performed a carotid artery resection and replacement using an artificial vessel Gore-Tex) in a case of neck cancer with infiltration into the carotid artery.

• Journal of Korean Society of Transportation
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• v.13 no.4
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• pp.61-77
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• 1995

The main objective of this research is the development of a logit model of urban workers' auto ownership choice. For the utility specification. a variety of behavioral hypotheses about the factors which affect the urban workers' auto ownership choice are considered. Based on the behavioral hypotheses, a binary logit model of auto ownership is estimated. Empirical estimation is based on a sample of workers taken in Daegu City(1994). The binary logit model of auto ownership development in this paper provides reasonable results in terms of behavioral and statistical considerations. Furthermore, this paper develops several submarket models of auto ownership choice. Market segmentation was made using age, sex, income, home-to-work time distance. It is found that the estimated results with market segmentation are also reasonable. Finally future directions of model development are suggested.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.91-94
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• 2003

In this study we propose the improvement countermeasure of disaster prevention by analyzing the damage cause and issue point from examination by Typhoon "maemi" in Kyongsangnamdo region. The main damage cause by Typhoon "maemi" in this region is the rising of water level in river and the overflowing of bank. The basic countermeasure is executing the disaster policy enforcement for the improvement of agriculture infrastructure facilities.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.299-302
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• 2003

This study aims to apply and compare flood routing methods for irrigation reservoirs. In this research, three methods, which are the storage indication method(SIM), the mass curve method(MCM), the frog method(FM) were adopted and applied to two storm events of July $9{\sim}10\;and\;22{\sim}23$ of Donghwa-dam and its watershed located on Jangsoo-gun, Chunnam province. As the application results MCM showed the highest value at peak overflow and goodness-of-fit to the observed value, although the others also had similar value with the observed one. In analyzing lag time of peak between inflow and overflow MCM and SIM showed 7 hours, while FM showed 6 hours for the first storm event, and all three methods showed 3 hours for the second event.

• Electronics and Telecommunications Trends
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• v.18 no.5 s.83
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• pp.1-10
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• 2003

최근의 폭발적인 인터넷 사용의 증가와 또 그것과 유사한 품질의 서비스를 이동중에도 제공 받고자 하는 사용자의 요구와 음성통화 시장의 포화에 따라 무선 데이터 시장을 새로운 돌파구로 보는 제조업체 및 서비스 제공자의 노력으로 IMT-2000 서비스가 이미 진행되고 있다. 비록 2세대 디지털 셀룰러에서 IMT-2000으로의 진화가 현재 지지부진 하지만, 2010년경의 데이터 사용량 예측을 참고로 할 때 새로운 시스템의 출현이 필연적이다. 본 논문에서는 최근까지 논의된 4세대 이동통신에 대한 시스템 및 서비스의 비전을 제시하고자 한다. IMT-2000에서 화상전화를 목표로 하였다면, 4세대에서는 Telepresence의 완벽한 구현과 유비쿼터스 시대로의 첫걸음으로서 다양한 네트워크와 컨버전스를 강조한다. 본 논문에서 이 두 가지 특징을 중심으로 4세대의 비전을 기술하고자 한다.

• Electronics and Telecommunications Trends
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• v.19 no.3 s.87
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• pp.12-21
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• 2004

본 고에서는 2010년경에 고속 이동 시 100Mbps, 정지 시에 1Gbps의 전송속도로 멀티미디어 통신서비스를 제공하는 새로운 능력을 가짐과 동시에 3세대, 2세대, 기타 무선접속기술을 모두 아우르는 시스템을 B3G(Beyond IMT-2000)으로 ITU에서 정의한 차세대 이동통신의 서비스 연구 동향을 ITU-R의 WP8F, EU의 WWRF, 일본의 mITF 서비스 연구동향을 개인 중심의 서비스 관점에서 살펴보았다. 또한 시나리오로부터 서비스 기능 및 서비스 기술을 추출하고 추출된 기술로부터 망구조 및 서비스절차를 작성한 ETRI 서비스 연구결과를 기술하였다.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.104-110
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• 2016

Main purpose of the current paper is to show results of time lag analysis using phase information of flame transfer function in order to predict combustion instabilities in a gas turbine combustor. The flame transfer function (FTF) is modeled using a commercial Computational Fluid Dynamics (CFD) code (Fluent). Comparisons of the modeled flame shapes with the measured ones were made using the optimized heat transfer conditions and combustion models. The FTF modeling results show a quite good agreement with the measurement data in predicting the phase delay (i.e. time lag). Time lag analysis results using the phase of FTF shows better combustion instability prediction accuracy than using time lag calculated from the steady state flame length.