• 한국물환경학회지
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• 제26권3호
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• pp.532-539
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• 2010

The synthetic unit hydrograph is developed and verified using Nash model and characteristic velocities considering geomorphological dispersion in this present study. Application watersheds are selected 5 subwatersheds of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. Characteristic velocities are calculated using estimated path lengths and moment characteristics of rainfall-runoff data. Characteristic velocities of random devised 7 ungauged watersheds are estimated through regional analysis of chracteristic velocities in guaged watershed. And Nash model parameters and IUH are derived using characteristic velocities and path length in the gauged and ungauged watershed. The result to compare of IUH about gauged watershed and random devised ungauged watershed in application watershed presents coherently hydrologic response characteristics that peak discharge is reduced and peak time is extended. In conclusion, Developed synthetic unit hydrograph in this study expects that it is useful method to estimate runoff discharge for managing of water pollution in ungauged watershed.

• 한국전자파학회논문지
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• 제21권2호
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• pp.188-193
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• 2010

본 논문은 관통형 비아와 전송 선로 사이의 임피던스 불연속과 P/G(Power/Ground) 면 사이에서 발생되는 공진으로 인한 클록 신호 응답 성능 저하가 관통형 비아(through-hole via)가 있는 4층 PCB(Printed Circuit Boards)의 SI(Signal Integrity) 성능에 악영향을 미치는 것을 이론적으로 분석하였다. 비아 구조의 집중소자 모델링을 이용한 반사 전압 계산과 TDR(Time Domain Reflector) 시뮬레이션 결과 비교로 관통형 비아와 전송 선로 사이의 임피던스 불연속 최소화 시킬 수 있고, 관통형 비아 위치를 이용한 P/G면 공진 상쇄의 시뮬레이션 결과로 클록 신호 응답 성능을 향상시킬 수 있음을 확인하였다.

• 한국통신학회논문지
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• 제19권3호
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• pp.523-532
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• 1994

GTEM cell의 특성 임피던스에 대한 정확한 값을 알면 그것을 설계하는데 매우 유용하다. 본 논문은 전자파 감응성 및 복사 측정 모두에 사용할 수 있는 GTEM cell을 그의 개방각을 고려한 특성 임피던스에 대해 논한다. 해석을 위해 over-RGM에 대해 기술하고, 이 수치해석법을 구좌표계에 실시한다. 몇가지 결과를 다른 논문의 것들과 비교하고, 본 해석의 정당성을 입증한다. GTEM cell 단면 상의 기하학적 구조변화에 따른 특성 임피던스 값들을 구하고 개방각이 특성 임피던스에 미치는 영향을 보인다. 마지막으로 여러 개방각에 대한 단면 상의 전계 균일도를 구한다.

• 한국전자파학회논문지
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• 제16권2호
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• pp.194-198
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• 2005

UNII(Unlicensed National Information Infrastructure) 밴드에서 대 역 저지 특성을 갖는 새로운 형태의 UWB 통신용 마이크로스트립 급전 원형 패치 안테나를 제안한다. 안테나의 대역 저지 특성은 inverted-U 슬랏을 이용하여 구현한다. 제안한 안테나는 inverted-U 슬랏의 길이를 변화시켜 대역 저지 주파수 범위를 결정한다. 측정된 안테나의 대역폭은 VSWR<2를 기준으로 $2.9\~12.1GHz$에 걸쳐 광대역 특성을 만족하며 $4.9\~6GHz$ 부근에서 대역저지 특성을 갖는다 안테나의 복사 패턴은 모포폴과 비슷한 전 방향성 특성을 나타내며 전 동작 주파수 대역에 걸쳐 균일한 이득 특성을 갖는다.

• 한국기계가공학회지
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• 제11권1호
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• pp.26-32
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• 2012

Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study will report the characteristic of wafer according to processing time, machining speed and pressure which have major influence on the abrasion of Si wafer polishing. It is possible to evaluation of wafer abrasion by load cell and infrared temperature sensor. The characteristic of wafer surface according to processing condition is selected to use a result data that measure a pressure, machining speed, and the processing time. This result is appeared by the characteristic of wafer surface in machining condition. Through that, the study cans evaluation a wafer characteristic in variable machining condition. It is important to obtain optimal condition. Thus the optimum condition selection of ultra precision Si wafer polishing using load cell and infrared temperature sensor. To evaluate each machining factor, use a data through each sensor. That evaluation of abrasion according to variety condition is selected to use a result data that measure a pressure, machining speed, and the processing time. And optimum condition is selected by this result.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.934-937
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• 2003

In this paper, authors use a stereo vision system based on the visual model of human and establish inexpensive method that recognizes moving distance using characteristic points around the robot. With the stereovision. the changes of the coordinate values of the characteristic points that are fixed around the robot are measured. Self-displacement and self-localization recognition system is proposed from coordination reconstruction with those changes. To evaluate the proposed system, several characteristic points that is made with a LED around the robot and two cheap USB PC cameras are used. The mobile robot measures the coordinate value of each characteristic point at its initial position. After moving, the robot measures the coordinate values of the characteristic points those are set at the initial position. The mobile robot compares the changes of these several coordinate values and converts transformation matrix from these coordinate changes. As a matrix of the amount and the direction of moving displacement of the mobile robot, the obtained transformation matrix represents self-displacement and self-localization by the environment.

• Earthquakes and Structures
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• 제15권2호
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• pp.123-132
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• 2018

In this paper the strain energy density (SED) model is used to analyze the seismic behavior of suspen-domes and a new criterion is established for judging the seismic failure based on a characteristic point in the SED model. Firstly, a nonlinear time-history response analysis was carried out using the finite-element package ANSYS for typical suspen-domes subjected to different ground motions. The seismic responses including nodal displacements, ratios of yielding members, strain energy density and structural maximum deformation energy were extracted corresponding to the increasing peak ground acceleration (A). Secondly, the SED sum ($I_d$) was calculated which revealed that the $I_d-A$ curve exhibited a relatively large change (called a characteristic point) at a certain value of A with a very small load increment after the structures entered the elastic-plastic state. Thirdly, a SED criterion is proposed to judge the seismic failure load based on the characteristic point. Subsequently, the case study verifies the characteristic point and the proposed SED criterion. Finally, this paper describes the unity and application of the SED criterion. The SED method may open a new way for structural appraisal and the SED criterion might give a unified criterion for predicting the failure loads of various structures subjected to dynamic loads.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2303-2308
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• 2010

We studied the cost-volume supply characteristic of public transportation systems focused on Bi-modal Tram in the main cities to analyze the applicability and status for the new transit system Bi-modal Tram as public transportation system. The operation cost considering the characteristic of vehicle, facilities, operation and average cost for respective public transportation system and the time cost considering the travel and transfer time are defined to the social cost, and the cost-volume supply curve is based on this social cost. The cost-volume supply characteristic between public transportation modes in the city is determined on the basis of cost-volume supply curve. Through the comparison between cost-volume supply characteristic of main transportation systems, it is analyzed about the relation between public transportation systems in the city and the characteristic for proper service provision. The application of Bi-modal Tram in the city is concluded that it is effective to reduce the social cost on the existing public transportation system.

• 상하수도학회지
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• 제28권5호
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• pp.581-587
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• 2014

Sediment basin that is typical facility installed for development business to prevent soil erosion has low removal efficiency and therefore, it causes complaints from the residents and has a bad effect on ecosystem. Thus there is a limit to control soil erosion using the existing design methods of sediment basin, so the purposes of this study is providing suitable design factors for sediment basin with regarding soil characteristic of development areas and analysing sedimentation characteristic by inflow concentration changes. The results, for analyzing the sedimentation characteristic by soil concentrations within approximately 2,000 ~ 20,000 mg/L of initial SS concentration, indicated similar sedimentation trends for same soil in the supernatant regardless of initial concentrations. However, for different soil characteristic (percent finer), there are different results in sedimentation rate and concentrations of the supernatant. Thus it is recommended that sediment basin to prevent soil erosion during construction should be designed based on retention time derived from soil sedimentation experiments regardless of inlet concentration. In addition, installing the soil erosion prevention facility at the back to satisfy effluent water quality should be considered to minimize soil erosion effectively.

• 드라이브 ㆍ 컨트롤
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• 제10권3호
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• pp.27-33
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• 2013

Solenoid valve has used in various industrial field extensively. A solenoid valve has different size, shape and method of operation accordantly to industrial field. Many researchers study on kinds of solenoid valve such as flow rate, dynamic, magnetic field, valve shape and operating method. But the flow rate characteristic and dynamic response time performance on the diaphragm valve are not studied. This paper describes the flow rate characteristic and dynamic response time performance on the diaphragm valve. At first, the diaphragm valve is simulated in AMESim simulation tool. AMESim model found that an effect of valve performance depends on parameter. The parameter is the diaphragm orifice area. And the performance test bench confirms the effect in this parameter. Finally, it finds out the flow rate characteristic and dynamic response time performance on the diaphragm valve.