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        검색결과 500

        486.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to estimate the low-flow statistics at the mountainous watershed. The formulation for the estimation of the design low-flow statistics was obtained by means of a hydraulic approach applied to a simple conceptual model for a mountainous watershed. Three of the independent variables associated with the low-flow statistics is watershed area(A), average basin slope(S) and the base flow recession constant(K); Watershed area was measured from topographic maps and average basin slope is approximated in this study using Strahler's slope determining method. And base flow recession constant computed using Vogel and Kroll's method. Unfortunately, this method is usually unavailable at ungaged sites. In this study, recession constant at ungaged sites is estimated using graphical regression method used by Giese and Mason. The model for estimating low-flow statistics were applied to all 61 catchments in the Sumjin, Mankyung basin.
        488.
        1999.04 KCI 등재 서비스 종료(열람 제한)
        GIS기법을 이용하여 추출되는 수문지형정보는 기존 주제도의 선정, 사용된 알고리즘 등에 따라 달라질 수 있다. 따라서 본 연구에서는 토양도 및 토지이용도의 선정에 따른 유출수문곡선번호의 변화를 분석하여 미계측 유역의 강우유출모의에 효과적인 GIS의 활용방안을 제시하고자 한다. 이를 위해 미계측 유역에서의 유효강우량 산정에 필요한 GIS 공간자료(개략토양도, 정밀토양도, 토지이용계획도,위성영상)를 구축하였다. 미국 토양보존국(SCS)의 유출곡선번호(run
        490.
        1998.12 서비스 종료(열람 제한)
        A digital image processing technique which is able to be used for getting the velocity vector distribution of a surface of the spilt oil in the ocean without contacting the flow itself. This technique is based upon the PIV(Particle Imaging Velocimetry) technique and its system mainly consists of a high sensitive camera, a CCD camera, an image grabber, and a host computer in which an image processing algorithm is adopted for velocity vector acquisition. For the acquisition of the advective velocity vector of floating matters on the ocean, a new multi-frame tracking algorithm is proposed, and for the acquisition of the diffusion velocity vector distribution of the spilt oil onto the water surface, a high sensitive gray-level cross-correlation algorithm is proposed.
        491.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        A quick and automatic detection with no harm to the goods is very important task for improving quality control, process control and labour reduction. In real fields of industry, defect detection is mostly accomplished by skillful workers. A narrow band eliminating spatial filter having characteristics of removing the specified spatial frequency is developed by the author, and it is proved that the filter has an excellent ability for on-line and real time detection of surface defect. By the way,. this spatial filter shows a ripple phenominum in filtering characteristics. So, it is necessary to remove the ripple component for the improvement of filter gain, moreover efficiency of defect detection. The spatial filtering method has a remarkable feature which means that it is able to set up weighting function for its own sake, and which can to obtain the best signal relating to the purpose of the measurement. Hence, having an eye on such feature, theoretical analysis is carried out at first for optimal design of narrow band eliminating spatial filter, and secondly, on the basis of above results spatial filter is manufactured, and finally advanced effectiveness of spatial filter is evaluated experimentally.
        495.
        1998 서비스 종료(열람 제한)
        A digital image processing technique which is able to be used for getting the velocity vector distribution of a surface of the spilt oil in the ocean without contacting the flow itself. This technique is based upon the PIV(Particle Imaging Velocimetry) technique and its system mainly consists of a high sensitive camera, a CCD camera, an image grabber, and a host computer in which an image processing algorithm is adopted for velocity vector acquisition. For the acquisition of the advective velocity vector of floating matters on the ocean, a new multi-frame tracking algorithm is proposed, and for the acquisition of the diffusion velocity vector distribution of the spilt oil onto the water surface, a high sensitive gray-level cross-correlation algorithm is proposed.
        497.
        1997.09 KCI 등재 서비스 종료(열람 제한)
        It is very important to measure and monitor hull stress which is caused by a buoyant force and a weight of cargo for safety of ship. However, an exact measurement of hul stress, using the traditional strain gage which is made of metal or semiconductor, is very difficult, because a ship would be exposed by the severe temperature environment of -20 ℃ to 80 ℃. This paper propose a new concept strain gage which can improve accuracy and compensage effectively affects due to temperature. The strain gage is consists of two parts. One is the Hull Deformation Amplifier which introuce several lever and link system, and another is a transducer converting distance into voltage signal. The HDA measure the amount of deformation and amplify it. And a lever and link system of the HDA is introduced for compensating temperature deformation by installing in perpendicular direction without stress. This paper also reports on the results of the experiments to verify linearity of the strain gage.
        498.
        1996.06 KCI 등재 서비스 종료(열람 제한)
        For the smooth flow of traffic vehicles and its effective management, it is necessary to have an exact information on traffic condition, i.e., the volume of traffic, velocity, occupancy and classification of vehicles. In particular, for classification of vehicles, there has been only image processing method using camera, where the method can obtain much information but rather expensive. In this paper, an algorithm for the measurement of velocity and total length of vehicles has been proposed to develop a general traffic management system, which is necessary to discriminate the class of vehicles. In order to realize the proposed algorithm, we have developed an ultrasonic spatial filtering method, which has better performance than that of using the traditional vehicle detector. To have this system to be constructed, we have introduced three sets of ultrasonic devices where each has one transmitter and two receivers which are arranged to obtain the spatial difference of objects. The velocity of vehicles can be measured by analyzing the occurrence time of pulses and their time differences. The total length of vehicles can be given by multiplying velocity with time interval of pulses sequence. To confirm the effectiveness of this measuring system, the experiment by the spatial filtering method using the ultrasonic sensors has been carried out. As the results, it is found that the proposed method can be used as one of measurement tools in the general traffic management system.
        499.
        1996.02 KCI 등재 서비스 종료(열람 제한)
        On this paper, the traditional methods for the measurement of ship's maneuverabilities during the sea-trial of newly built ship are summarized and new methods for the same measurement using Integrated Navigation System and GPS are introduced. After various sea-trials of training ship "HANNARA" which are equipped with modern INS and GPS system, the results are compared and analysed. The purpose of this paper is to present more accurate methods of measurement of ship's maneuverabilities during sea-trial using INS and GPS which are gradually becoming the basic navigational equipments on many newly constructed vessels.d vessels.
        500.
        1994.11 KCI 등재 서비스 종료(열람 제한)
        On developing port system, the performance tests of system in relation to ship maneuver generally consists of the three parts: the channel transit, the manoeuvring in a turning basin and the docking/undocking. The quantifications of risk of an accident has priviously been difficult due to the low occurrence of accidents relative to the number of transits. Additionally, accident statistics could not be related port system because of the large number of factors contributing to the accident. such as human error, equipment failure, visibility, light, traffic. etc. In case of the channel transit, "Relative Risk Factor(RRF)" or "Relative Risk Factor for Meeting Traffic" was proposed as the as the measures derived to quantify the relative risk of accident by M.W.Smith. This factor measure the tracking performance, the turning performance and the passing performance at meeting traffic. On the other hand, the safety of berthing maneuver is not measured with a few evaluating factors as controlled due to complex controllabilites such as steering, engine, side thrusters or tugs. This work, therefore, aims to propose the evaluating measure by the Analytic Hierarchy Process(AHP). Six experimental scenarios were establised under the various environmental conditions as independent variables. In every simulation, the difficulty of maneuver was scored by captain and compared with AHP scores. The results show almost same and from which the weights of eight evaluating factors could be fixed. Additionally, the limit value of relative factor in berthing safety to six scenarios could be estimated to 0.11.e estimated to 0.11.