• 대한교통학회지
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• 제8권2호
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• pp.67-75
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• 1990

This paper treats the problem to schedule for trains with how transit priority so as to maximizing the number that can be sent during given time periods without interfering with the fixed schedule for train with high transit priority in a track. We transform the this problem into Time Expanded Network without traverse time through application of Ford and Fulkerson Model and construct the Enumeration Algorithm for solutions using TENET Generator (TENETGEN). Finally, we compare our algorithm with Dinic's Maximal-Flow Algorithm and examine the avaliability of our procedures in personal computer.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권1호
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• pp.38-43
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• 2016

Purpose: Each ethnic group has a unique life style, including diets. Life style affects bowel movement. The aim of this study is to describe the results of colon transit time (CTT) tests in Korean children who had chronic functional constipation based on highly refined data. Methods: One hundred ninety (86 males) out of 415 children who performed a CTT test under the diagnosis of chronic constipation according to Rome III criteria at Konkuk University Medical Center from January 2006 through March 2015 were enrolled in this study. Two hundreds twenty-five children were excluded on the basis of CTT test result, defecation diary, and clinical setting. Shapiro-Wilk and Mann-Whitney U, and chi-square tests were used for statistical analysis. Results: The median value and interquartile range (IQR) of CTT was 54 (37.5) hours in Encopresis group, and those in non-encopresis group was 40.2 (27.9) hours (p<0.001). The frequency of subtype between non-encopresis group and encopresis was statistically significant (p=0.002). The non-encopresis group (n=154, 81.1%) was divided into normal transit subgroup (n=84, 54.5%; median value and IQR of CTT=26.4 [9.6] hours), outlet obstruction subgroup (n=18, 11.7%; 62.4 [15.6] hours), and slow transit subgroup (n=52, 33.8%; 54.6 [21.0] hours]. The encopresis group (n=36, 18.9%) was divided into normal transit subgroup (n=8, 22.2%; median value and IQR of CTT=32.4 [9.9] hours), outlet obstruction subgroup (n=8, 22.2%; 67.8 [34.8] hours), and slow transit subgroup (n=20, 55.6%; 59.4 [62.7] hours). Conclusion: This study provided the basic pattern and value of the CTT test in Korean children with chronic constipation.

• 국제초고층학회논문집
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• 제12권1호
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• pp.35-47
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• 2023

The transport system and its infrastructure are not only the fundamental means of sustaining the operation of contemporary cities, but also important drivers for the evolution of urban form. Rail transit, critical to improving the operational efficiency and optimizing the spatial layout in cities, is one of the critical conditions for high-density areas with limited land and concentrated resources to be compact to take on complex challenges. As a node element of infrastructure, rail transit entrances are the most important points connecting the rail transit system with urban space. Although influenced by urban form, their quantity and location also influence and shape the evolution of urban space form. Based on the development gap of high-density areas in various contexts, focusing on various rail transit stations in Asia, this research analyzes the correlation between rail transit entrances and peripheral high-density urban form in a delicate, dynamic and granular way. The research considers both horizontal and vertical perspectives, in combination with the urban evolution process in time series, to explore the development trend of high-density urban form in Asia from the aspect of correlation, and building a new foundation for research on urban form, suitable for different types of cities.

• 한국철도학회논문집
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• 제9권1호
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• pp.23-28
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• 2006

Many services have been served by the exiting subway systems since they have opened in 1975. But its efficiency and competition were going down because of the high construction cost and difficult connection with other transportations, etc. Otherwise, the light rail transit system is much lower construction cost than the subway and the high way building. Also those systems are good at the inexpensive operation cost, the fixed time and safety, the easy access. Recently, the several provinces are planning or advancing the light rail transit system because of these many benefits. Consequently, those system's economical feasibility analysis is required rapidly to show the resonable construction's cause and to get the private investment. This paper offers the system's economical feasibility through the several benefit analysis after the light rail transit system's construction.

• 한국도로학회논문집
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• 제14권3호
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• pp.163-171
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• 2012

수요대응형 교통수단(Demand Responsive Transit)은 변화하는 이동수요에 대응하는 탄력적인 교통수단으로 단순히 노약자와 장애인을 위한 복지교통 서비스의 영역이 아니라, 무선통신과 위치정보서비스(Location Based Service: LBS)의 발달로 인하여 도심형 수단으로 보다 효율적인 교통수단으로 자리매김하고 있다. 그러나 문전서비스(Door-to-Door)를 제공하는 수요대응형 교통수단 시뮬레이션에 적합한 상용툴의 부재로 인하여 알고리즘이나 차량 운행 요소를 면밀하게 분석하기 힘든 어려움이 있었다. 본 연구는 수요대응형 교통수단에 연관된 다양한 차량 운영계획과 알고리즘을 구현, 평가할 수 있는 시뮬레이션 환경을 제안한다. 문전서비스(Door-to-Door) 기반의 차량 운행 모형을 적용하기 위하여 확보되어야 하는 시뮬레이션 입력 데이터를 정의하고 있으며, 수요대응형 교통수단의 대표적인 범주에 속하는 실시간 합승 택시(Shared-Taxi) 서비스를 서울시 교통망과 택시 수요를 이용하여 적용하였다. 합승 택시 운행 계획을 위하여 Nearest Vehicle Dispatch(NVD)와 Insertion Heuristic(IH), 두 종류의 알고리즘을 제안하였으며, 제안된 시뮬레이션을 통하여 성능을 비교하였다. 또한, 합승(Ride-sharing)을 허용하지 않는 일반적인 택시와의 비교를 통하여 시스템 효율 향상과 서비스 품질 변화를 분석하였다.

• 대한전자공학회논문지SD
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• 제39권10호
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• pp.9-15
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• 2002

드리프트 영역에서의 속도 오버슈트 효과를 이용하여 서브밀리미터파 주파수 영역에서 동작하는 새로운 주행 시간 소자를 제안한다. 이 소자를 속도 오버슈트 주행 시간(VOTT) 다이오드라 명명한다. 이 소자는 캐리어 주입 메커니즘으로 빠르게 이루어지는 이종구조 터널링을 이용하며, 속도 오버슈트 효과를 최적화하기 위하여 짧은 드리프트 영역을 갖는다. 변환효율을 증대시키기 위하여 에너지 대역 간극을 경사시키는 방법으로 드리프트영역을 설계한다. 모의실험결과에 따르면 이 소자는 THz 영역에서 동작하리라 기대된다.

• 생명과학회지
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• 제11권4호
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• pp.298-303
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• 2001

The hypolipidemic effect of the diet containing uncooked food was evaluated in hyperlipidemic rats. Body weightgain, food intake and food efficiency ratio were not significantly different among the diet groups examined. Significant decrease in plasma total cholesterol(8.8%), triglyceride(10.0%) and LCL-cholesterol(34.8%) were observed in uncooked food diet groups, and the liver total cholesterol and triglyceride level to the extent of 8.7% and 16.7%, respectively. Uncooked food groups substantially increased the plasma HDL to total cholesterol ratio(47.2%) and decreased the atherogenic index(37.6%) as well. Gut transit time for uncooked food was significantly higher, up to 104 minutes, compared to that of control diet group. These results suggest that uncooked food may have beneficial effects on blood lipid level and gut transit time in hyperlipidemc rats.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.378-386
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• 2002

Multi-path ultrasonic Sow measurement system uncertainty is determined by assigning an expected error of each component of flow measurement and then defining the total flow measurement uncertainty as square root of the sum of squared values of the individual error. Sources of uncertainty for flow measurement are geometry, transit time and velocity profile integration uncertainty. A theoretical uncertainty model for multi-path ultrasonic transit time flowmeter configured with parallel 5 chords, is derived from and calculated by dry calibration method.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.405-408
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• 1998

Due to the large conduction band discontinuity between emitter base, OmGaAs HBT has an advantge to enable the hot electrons to inject into the base. In this paper, InAlGaAs/InGaAs HBT with the various emitter junction gradings and the modified collectors are simulated and analyzed by HMC(hybrid monte carlo) simulator in order to find a optimal structure for the shortest transit time. A minium base transit time (.tau.$_{b}$ ) of 0.21 ps was obtained for HBT with the grading layer, which is parabolically graded from x=1.0 to x=0.5. The minimum collector transit time (.tau.$_{c}$ ) of 0.31ps was found when the collector was modified by inserting p$^{[-10]}$ and p$^{+}$ layers. Thus HBT in combination with the emitter grading and the modified collector layer showed the cut-off frequency (f$_{T}$) of 183GHz.z.z.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1046-1050
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• 2003

In this paper, we describe study on the development or multi-path ultrasonic gas flowmeter using a transit time method. This system includes 5 pairs of ultrasonic transducers. ultrasonic signal processing unit using switch matrix method, computation algorithm of gas flow rate, spool piece type multi-path pipe unit. We have developed enhanced type of main ultrasonic signal processing unit using switch matrix method fer multi-path ultrasonic gas flowmeter. Also, we have developed the new transmitting ＆ receiving method of ultrasonic waves and the new signal processing algorithm for the computation of ultrasonic transit time from received ultrasonic waves. In this study, we have designed more compact signal processing unit compared with the conventional hardware system of multi-path ultrasonic gas flowmeter. We have confirmed its reliability for multi-path ultrasonic gas flowmeter through the laboratory test using calibration system. In the future. we will perform the field test for the developed system in the POSCO gas line.