개선된 교통 신호 제어시스템 설계에 관한 연구

김대성,허광선,권민수,곽동호,원충상 忠州大學校 2010 한국교통대학교 논문집 Vol.45 No.-

There are various ways to operate traffic light system by varying the operational speed of the system. One of the solutions is to vary the length of the clock cycle of the system. It is difficult to vary the length of the signal in systems by varying the period of the clock cycle and nor it is a generalized technology in the current traffic systems. The traffic signal systems of the past used is simply a repetitive traffic signal system which traffic period is consistent, not considering the conditions of traffics. The system that will be introduced in this thesis could substantially improve efficiency of traffic flows by varying the length of traffic signal period with sensors which detect the presence of vehicles on both directions and allows the signal continuously on the direction where there are more waiting vehicles, and even skips the signal where there is no vehicle waiting. In this thesis, it introduces the methodology of detecting the spots that is detected by the sensors of the system and outputs green light in due order in accordance with the priority given to the system. In the meanwhile, the ratio of yellow light and green light is designed to be 1 to 8 in the way that maximizes the efficiency of traffic flows.

도암호의 수질과 어류군집 특성 연구

이상하,최재석,이광열,장영수,임인수,허우명,김재구,김범철 강원대학교 부속 환경연구소 2005 Journal of the Environment Vol.2 No.-

To investigate nutrient dynamics of the lake and fish community, both water and fish samples were collected at three different areas (dam site, upper inflowing and downstream of lake outfow) for one year from Sep.2004 to Aug.2005 During the experimental periods, mean concentration of chl, a in epilimnetic layer (0-5m) was 18.5mg^(-3) and transparency ranged from 0.3m to 2.4m, respectively. In nutrient, mean concentrations of TP and TN were 111 mgP m^(-3) and 4.4 mgN L^(-1), respectively. Based on the water quality standard suggested by U.S.EPA(*1976), the trophic state of Lake Doam was classified as eutrophic state. Total number of fish collected in Lake Doam was 9,600 indiveduals in 26 species of 6 family. Sixteen of Korean endemic soecies including H. mylodon, A. signifer, P. tenuicorpa occurred. O. mykiss as introduced fish was also found in Lake Doam. Dominant and subdominant species were P. herzi and Z. platypus that took about 34.6% and 22.5% of total fish composition, respectively. Six species including A. signifer. P. tenuicorpa. and R. kumgangensis were rare in Lake Doam. Pelagic typw of figh commonly occurred at upper regions, whereas benthic type was mainly domenated at downstream area. Therefore, pollution source inflowed from the upper regions did not seriously affect downstream area (Songcheon water system) due to the role of dam as pollutant barrier. In addition high appearance of Comat type of fish that si hybrid between gold fish (C.auratus) and C. auratus was found in the lake, It was unclear the reasons that high prorortion of mutant species apperared in the lake. Further more researches are required in this area.

사이클론 집진기의 벽면구배에 따른 압력손실과 컷 사이즈 변화 예측 모델 개발

허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

In previous studies, Convex cyclone are proposed to reduce pressure loss which are design cyclone wall with a single continuous curve. Studies about a prediction model for pressure loss and cut-size has focused on conventional cylinder-on-con cyclone. Therefore, the models do not perform well for uncommon design. In this study, a predict model for pressure loss and cut-size depend on cyclone wall curvature are developed. The tangential velocity below vortex-finder is obtained with consideration about friction area and momentum loss on the cyclone wall, and with this the variation of vortex-core and core velocity is obtained. Pressure loss is predicted using a Rankine vortex hypothesis. The prediction results are well agreed with experiments and CFD results.

Convex 사이클론의 등급집진효율과 압력 손실에 관한 실험적 연구

허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

Cyclone separator is one of the most widely used devices to separate and recover the industrial dusts from air or process gases. We developed Convex cyclone to reduce pressure losses. The body of Convex cyclones are designed with single continuous curve and convex shape as a substitute for cylinder-on-cone geometry. With a previous studies, experimental result shows that Convex cyclone are efficient for pressure loss reduction. However, there seems to be no clear explanation about collection efficiency. In this study, we perform additional experiments for a in-depth comprehension of Convexcyclone with particle counting collection efficiency measurement method. The experimental result shows that Convex cyclone can achieve maximum 40% pressure loss reduction with about 0.5㎛ cut-size increasement. In addition, the experimental results indicated the existence of optimum convexity, minimum pressure loss, of cyclone wall.

등급집진효율 곡선의 기울기가 2단 사이클론의 집진효율에 미치는 영향

허광수(Heo Kwang Su),설승윤(Seol Seoung-Yun),김민하(Kim Min Ha) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4

A collection efficiency of cyclone is influenced by cut-size and slope of grade efficiency curve. It has been recognized that the collection efficiency is improved when the cut-size is reduced. However, effects of the slope have never been studied so far. In this study, we analyze a relationship between slope of grade efficiency and collection efficiency in two-stage cyclones. In single stage cyclones, higher slope cyclones have high efficiency. On the contrary to single stage cyclone, collection efficiency of two-stage cyclone have the maximum value when the first cyclone has a lower slope and second cyclone is high.

Swirl Tube 집진기 내의 입자 거동에 대한 연구

허광수(Kwang Su Heo),설승윤(Seoung Yun Seol) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

In order to offer basic guidelines for efficient design of swirl tube separator, the particle behavior of undecayed fully developed rotational flow with different swirl number are simulated. The velocity field of swirl tube are obtained by Large eddy simulation and the particle motion is modeled using Basset-Boussinesq-Oseen equation and integrated with forth order Runge-Kutta method. It is assumed that the density of particle is much larger than that of fluid, Basset force and added mass term are therefore neglected. The required flight time to reach separator inner wall and exit are calculated and compared with the result of conventional time of flight model. Particle rebounce at the inner wall that is a important reason of collection efficiency decrease, are also simulated.

가정용 냉장고의 도어 개폐 시 외부 고온/고습 공기의 유입에 대한 실험적 연구

허광수(Kwang Su Heo),이상진(Sang Jin Lee),김현주(Hyun Joo Kim),서응렬(Eung Ryeol Seo) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

The purpose of this study is to establish quantitatively the influence of intake air flow with high temperature and high humidity during door opening process. The humidity inflow of freezer compartment is increased by relatively high humidity air from outside of refrigerator and is decreased and eventually stabilized while the intake humidity is turned as frost mainly on the surface of evaporator and secondly on the surface of interior parts. In this study the temperature and humidity variation have been measured with the parameters such as internal setting temperature and outside temperature. The humidity has been measured for the air passing through the evaporator as a reference without door opening. As a measurement result, external air inflow is affected by the temperature difference between inside and outside and moisture inflow is dominantly influenced by dew point difference. Inflow rate of external air is increased in proportion to the temperature difference and humidity inflow rate is inversely proportional to the dew point difference. The humidity changes in the evaporator, is not related to the inlet air and evaporator temperature. The relative humidity of evaporator outlet only affects the relative humidity of the inlet air.

사이클론 집진기의 벽면 구배에 따른 압력손실과 등급집진효율에 대한 수치적 연구

허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

A pressure loss and dust collection performance of a cyclone dust separator have a relationship that trade off each other. Therefore, the design of the cyclone dust separator is a process in a quest for reasonable balance between collection efficiency and pressure loss. A number of theories about collection efficiency and pressure drop are introduced. However, those theories do not complete enough to be used to find an optimal design for a given operation condition directly. Therefore, there is a wide range of cyclone geometries in use, studies on new cyclone geometry are conducted lively. Our previous experiments show that the Convex cyclones are very effective for pressure loss reduction. The body of Convex cyclones are designed with single continuous curve and convex shape as a substitute for cylinder-on-cone geometry. In this study, we perform CFD simulation for a in-depth comprehension about flow pattern and particle behaviour of Convex cyclone.

코어유동모델과 익형이론을 이용한 사이클론 동압회복 기구의 설계

허광수(Heo Kwang-Su),설승윤(Seol Seoung-Yun) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.9

Pressure loss of cyclone consists of cyclone body friction loss and dynamic pressure loss of vortex finder which hold most of cyclone pressure loss. The pressure recovery vane or rectifier is generally used mechanism to convert rotational flow in vortex finder into axial flow. Conventional circular arc rectifier has no theoretical design guide line and depends on trial error. In this paper, we propose a theoretical design method of pressure recovery vane to reduce pressure loss in cyclone vortex finder. Core flow model is used to decide the angle of attack and width of vane. Theory shows that there exists an effective width of vane. The shape of pressure recovery vane is borrowed from the static blade of axial blower using NACA airfoil data. The design method of axial blower static blade provides theoretical guide line that can decide number of vane and stagger angle.

Single Lap Riveted Joint의 베어링 거동 연구

허광수(Heo Kwang-Su),윤성호(Yoon Sung-Ho),정종철(Jeong Jong-Cheol),이상진(Lee Sang-Jin),김정석(Kim Jung-Seok) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

In this study, bearing response in single lap riveted joint is investigated by menas of single lap shear specimens with different types of adherend and fastener. Single lap shear specimen consists of adherend of SUS403 and carbon fabric/epoxy composite. Rivet of Avdel 2691 with 9.6㎜ diameter is used. Two types of fastener in single lap riveted joint are considered. One is a single lap shear specimen with single fastener, and the other is a single lap shear specimen with double fasteners. Especially, in case of single lap shear specimen with single fastener, the width of the specimen is varied as 2D, 3D, 4D, 6D at a fixed edge distance of 3D. Also the edge distance of the specimen is varied as 1.0D, 1.5D, 2.0D, 2.5D, 3.0D at a fixed width of 4D. In case of single lap shear specimen with double fasteners, two types of specimen are considered. One is a specimen with the width of 6D and edge distance of 3D. The other is a specimen with the width of 4D and edge distance of 2D. Here D designates the hole diameter for riveted joint.