• 제목/요약/키워드: Valid Time

검색결과 725건 처리시간 0.027초

항공 카메라 검정을 위한 테스트 필드 구축방안 (Establishment of Test Field for Aerial Camera Calibration)

  • 이재원;윤종성;신진수;윤부열
    • 대한공간정보학회지
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    • 제16권2호
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    • pp.67-76
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    • 2008
  • 최근 항공측량분야의 가장 큰 기술적 특징은 Camera 혹은 Lidar와 같은 주 센싱 장비에 GPS, IMU 등 다양한 위치결정 센서를 연계한 Direct Georeferencing 기술의 활용이다. 아울러 항측용 디지털 카메라의 기술적 우월성과 이의 활용성이 입증됨에 따라 다양한 종류의 항측용 디지털 카메라가 개발 및 보급되고 있다. 이에 부응하여 국내에서도 일반적인 항공촬영으로는 취득이 불가능한 건물측면과 비고가 큰 지형에서 발생하는 사각지역에 대하여도 3차원 정보취득과 Texture Mapping이 가능한 다각(Multi-looking)항공촬영시스템의 개발이 시도되고 있다. 하지만 다양한 센서 결합과 다중 카메라의 배열에 따른 센서들간의 시각동기화와 함께 정확한 기하 및 복사보정을 실시해야 하는 문제점이 따른다. 이를 해결하기 위해서는 항공측량 시스템의 센서검정(Sensor Calibration)에 필요한 테스트 필드가 절실히 요구되고 있다. 따라서 본 연구에서는 항공측량용 테스트 필드 구축과 관련한 국외 사례를 고찰하고 국내 테스트 필드 구축방안을 제시하고자 한다.

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천해역에 수표면 및 수중방류된 사각형제트의 흐름 거동 (Flow behaviors of square jets surface discharged and submerged discharged into shallow water)

  • 김대근;김동옥
    • 상하수도학회지
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    • 제25권5호
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    • pp.627-634
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    • 2011
  • In the present study, the flow behaviors of square jets surface discharged and submerged discharged into shallow water were each simulated using computational fluid dynamics, and the results were compared. As for the verification of the models, the results of the hydraulic experiment conducted by Sankar, et al. (2009) were used. According to the results of the verification, the present application of computational fluid dynamics to the flow analysis of square jets discharged into shallow water was valid. As for the wall jet, which is one form of submerged discharges, at the bottom wall boundary, the peak velocity of the jet rapidly moved from the center of the jet to the bottom wall boundary due to the restriction of jet entrainment and the no-slip condition of the bottom wall boundary, and, as for the surface discharge, because jet entrainment is limited on the free water surface, the peak velocity of the jet moved from the center of the jet to the free water surface. This is because jet entrainment is restricted at the bottom wall boundary and the surface so that the momentum of the central core of the jet is preserved for considerable time at the bottom wall boundary and the surface. In addition, due to the effect of the bottom wall boundary and the free water surface, the jet discharged into shallow water had a smaller velocity diminution rate near the discharge outlet than did the free jet; at a location where it was so distant from the discharge outlet that the vertical profile of the velocity was nearly equal (b/x =20~30), moreover, it had a far smaller velocity diminution rate than did the free jet due to the effect of the finite depth.

항장요법(肛腸療法)에 의한 소시호탕(小柴胡湯)의 아나필락시 쇼크 억제(抑制)에 대한 실험적(實驗的) 연구(硏究) (Experimental Study of Inhibitory Effect on Anaphylactic Shock of Sosihotang by Anal Therapy)

  • 강태희;문석재;문구;원진희;김형민
    • 대한한의학회지
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    • 제19권2호
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    • pp.439-449
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    • 1998
  • Anal Therapy is another way of taking medicine. It is a traditional pathway but not available in common situation. Nevertheless, It has many benifect and usefulness, it has not treated so much. Through Anal Therapy, the valid compound of Herb med can be reach to the desination in theory of the organism and loca1 medical action. The former is called Jung-Chei Theory(整體論), which is the one of the most important basements in building traditional Korean medicine. As there are many kinds of Anal therapy, this study use reservation type. Sosihotang(SSHT) is one of the well-known korean medicines for a long time. It is used for the treatment of such dieases as infectious diseases, hepatic diseases and gastroenteritis and so on. In this study, the author investigated the effect of an aqueous extract of SSHT by Anal therapy(Reservative Enema) in anaphylactic shock. The following results were obtained 1. SSHT inhibited anaphylactic shock 100% with a dose of 1.0 g/kg 1 hr before intraperitoneal injection of compound 48/80. SSHT significantly reduced serum histamine contents induced by compound 48/80. 2. SSHT (0.1 g/kg) also inhibited to 30.9% (P<0.05)) local cutaneous anaphylactic reaction activated by anti-dinitrophenyl (DNP) IgE. 3. The validity rate of reservative enema is as much as oral pathway. 4. In addition, SSHT dose-dependently inhibited the histamine release from the peritoneal mast cells by compound 48/80 or anti-DNP IgE. These results provide evidence that Anal Therapy(Reservative enema) of SSHT may be beneficial in the treatment of systemic and local anaphylactic reaction. Moreover, I wish another much sincere study of Anal Therapy (Reservative enema) would be obtained.

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성장곡선 모형 적용을 통한 기술수준평가 사례 연구 : 특정 수산과학기술 분야를 중심으로 (Case Study on Measuring Technology Level Applying Growth Curve Model: Three Core Areas of Fishery Science and Technology)

  • 김완민;박주찬;박병무
    • 수산경영론집
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    • 제46권3호
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    • pp.103-118
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    • 2015
  • The purpose of this paper is to discuss possibilities of applying growth curve models, such as Logistic, Log-Logistic, Log-Normal, Gompertz and Weibull, to three specific technology areas of Fishery Science and Technology in the process of measuring their technology level between Korea and countries with the state-of-the art level. Technology areas of hazard control of organism, environment restoration, and fish cluster detect were selected for this study. Expert panel survey was conducted to construct relevant panel data for years of 2013, 2016, and a future time of approaching the theoretical maximum technology level. The size of data was 70, 70 and 40 respectively. First finding is that estimation of shape and location parameters of each model was statistically significant, and lack-of-fit test using estimated parameters was statistically rejected for each model, meaning all models were good enough to apply for measuring technology levels. Second, three models other than Pearl and Gompertz seemed very appropriate to apply despite the fact that previous case studies have used only Gompertz and Pearl. This study suggests that Weibull model would be a very valid candidate for the purpose. Third, fish cluster detect technology level is relatively higher for both Korea and a country with the state-of-the-art among three areas as of 2013. However, all three areas seem to be approaching their limits(highest technology level point) until 2020 for countries with the state-of-the-art. This implies that Korea might have to speed up her research activities in order to catch up them prior to 2020. Final suggestion is that future study may better apply various and more appropriate models respectively considering each technology characteristics and other factors.

A Unified Analytical One-Dimensional Surface Potential Model for Partially Depleted (PD) and Fully Depleted (FD) SOI MOSFETs

  • Pandey, Rahul;Dutta, Aloke K.
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제11권4호
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    • pp.262-271
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    • 2011
  • In this work, we present a unified analytical surface potential model, valid for both PD and FD SOI MOSFETs. Our model is based on a simplified one dimensional and purely analytical approach, and builds upon an existing model, proposed by Yu et al. [4], which is one of the most recent compact analytical surface potential models for SOI MOSFETs available in the literature, to improve its accuracy and remove its inconsistencies, thereby adding to its robustness. The model given by Yu et al. [4] fails entirely in modeling the variation of the front surface potential with respect to the changes in the substrate voltage, which has been corrected in our modified model. Also, [4] produces self-inconsistent results due to misinterpretation of the operating mode of an SOI device. The source of this error has been traced in our work and a criterion has been postulated so as to avoid any such error in future. Additionally, a completely new expression relating the front and back surface potentials of an FD SOI film has been proposed in our model, which unlike other models in the literature, takes into account for the first time in analytical one dimensional modeling of SOI MOSFETs, the contribution of the increasing inversion charge concentration in the silicon film, with increasing gate voltage, in the strong inversion region. With this refinement, the maximum percent error of our model in the prediction of the back surface potential of the SOI film amounts to only 3.8% as compared to an error of about 10% produced by the model of Yu et al. [4], both with respect to MEDICI simulation results.

Individual Variation of Na Intake and Urinary Excretion in Korean Women

  • Park, Jung-A;Yoon, Jin-Sook
    • Journal of Community Nutrition
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    • 제1권2호
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    • pp.119-124
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    • 1999
  • The purpose of this study is to investigate the daily variation of Na intake as measured by dietary methods(weighing vs food analysis) and to examine the difference between urniary Na excretion and dietary Na intake in 9 healthy free living women aged 25-64 years living in Taegu, Korea. Information on the dietary Na intake for 5 consecutive days was collected using he weighing method. Twenty four-hour urine samples were collected for the same period to measure the urinary Na excretion. In order to figure out the difference of Na intake with respect to dietary assessment methodology, dietary intake was measured by the weighing method for three of a total 5 days. At the same time, the meals that subjects consumed each day were collected to analyze daily intake of each subject by the food analysis method. The mean Na intake of subjects for 5 consecutive days by the weighing method was 3558. 5mg. The mean of urinary Na excretion for the same period was 2847.5mg/ Na intake and Urinary Na excretion of each subject ranged from 4475.3 to 2838.4, from 4066.4rmg to 1936.1mg respectively. The mean of Na intake for 3 days by the analysis method and the weighing method were 3044.6mg and 3441.6mg, respectively. Each subject showed a great difference among day-to-day variation of Na intake by the weighting method, analysis method and urinary Na excretion method. Therefore, a short term study period may not be valid to estimate the true average Na intake.

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모노펄스 추적을 이용한 무인기 DoA 추정정밀도 향상 방안에 관한 연구 (A Study on UAV DoA Estimation Accuracy Improvement using Monopulse Tracking)

  • 손으뜸효태;윤창배
    • 한국전자통신학회논문지
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    • 제12권6호
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    • pp.1121-1126
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    • 2017
  • 비행체의 위치정보는 GPS 교란과 같은 위험성에 노출될 수 있기 때문에 위치를 추정하기 위해 관성항법장치와 같은 여러 연구가 수행되고 있다. DoA(: Direction of Arrival) 및 RTT(: Round Trip Time)을 이용한 위치추정 기법은 레이다시스템에 적용되어 비행체의 위치를 추정하는데 사용되고 있으며 무인기 데이터링크에 적용 가능하다. 무인기 데이터링크는 넓은 대역폭을 사용하기 때문에 다중혼 방식의 합 차패턴 생성 방식을 주로 사용하며 탑재체의 제한된 송신출력으로 낮은 SNR 영역을 포함하여 추적을 수행한다. 일반적으로 낮은 SNR에서 위치 추정오차는 증가하며 높은 SNR에서 부엽을 제한하지 못하면 추정된 DoA의 유효성이 상실된다. 본 논문에서는 부엽을 제한하고 낮은 SNR에서 증가하는 DoA 추정오차를 보정하기 위한 방안을 제시한다.

Design of Navigation Environment Generation Module of M&S Software for Integrated Navigation System Performance Evaluation

  • Kim, Heyone;Lee, Junhak;Oh, Sang Heon;So, Hyoungmin;Hwang, Dong-Hwan
    • Journal of Positioning, Navigation, and Timing
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    • 제7권2호
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    • pp.73-90
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    • 2018
  • Various navigation systems are integrated with the Global Navigation Satellite System (GNSS) to improve navigation performance so that continuous navigation information can be obtained even when navigation performance is degraded or navigation is not available due to the outage of GNSS. Time and cost can be reduced by evaluating performance of the integrated navigation system through Modeling and Simulation (M&S) software prior to the deployment of the integrated navigation system. The measurements of the navigation system should be generated to evaluate performance through of the navigation system M&S software. This paper proposes a method of designing a navigation environment generation module in M&S software of the integrated navigation system. To show applicability of the proposed method to M&S software design of the integrated navigation system, functions are verified through MATLAB. And then visual C++ based M&S software for the integrated navigation system is implemented to check the operation of the navigation environment generation module. The reference trajectory is generated and true measurements of Global Positioning System (GPS), Korea Positioning System (KPS), and enhanced Long range navigation (eLoran) are generated from the reference trajectory. The navigation results obtained from the true measurements are compared with the reference trajectories. The results show that the measurements generated using the design generation module by the proposed method are valid and the navigation environment generation module can be applied to M&S software of the integrated navigation system.

Damage detection of a cable-stayed bridge based on the variation of stay cable forces eliminating environmental temperature effects

  • Chen, Chien-Chou;Wu, Wen-Hwa;Liu, Chun-Yan;Lai, Gwolong
    • Smart Structures and Systems
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    • 제17권6호
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    • pp.859-880
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    • 2016
  • This study aims to establish an effective methodology for the detection of instant damages occurred in cable-stayed bridges with the measurements of cable vibration and structural temperatures. A transfer coefficient for the daily temperature variation and another for the long-term temperature variation are firstly determined to eliminate the environmental temperature effects from the cable force variation. Several thresholds corresponding to different levels of exceedance probability are then obtained to decide four upper criteria and four lower criteria for damage detection. With these criteria, the monitoring data for three stay cables of Ai-Lan Bridge are analyzed and compared to verify the proposed damage detection methodology. The simulated results to consider various damage scenarios unambiguously indicate that the damages with cable force changes larger than ${\pm}1%$ can be confidently detected. As for the required time to detect damage, it is found that the cases with ${\pm}2%$ of cable force change can be discovered in no more than 6 hours and those with ${\pm}1.5%$ of cable force change can be identified in at most 9 hours. This methodology is also investigated for more lightly monitored cases where only the air temperature measurement is available. Under such circumstances, the damages with cable force changes larger than ${\pm}1.5%$ can be detected within 12 hours. Even though not exhaustively reflecting the environmental temperature effects on the cable force variation, both the effective temperature and the air temperature can be considered as valid indices to eliminate these effects at high and low monitoring costs.

Experimental and numerical analyses on determination of indirect (splitting) tensile strength of cemented paste backfill materials under different loading apparatus

  • Komurlu, Eren;Kesimal, Ayhan;Demir, Serhat
    • Geomechanics and Engineering
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    • 제10권6호
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    • pp.775-791
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    • 2016
  • The indirect tensile strengths (ITSs) of different cemented paste backfill mixes with different curing times were determined by considering crack initiation and fracture toughness concepts under different loading conditions of steel loading arcs with various contact angles, flat platens and the standard Brazilian test jaw. Because contact area of the ITS test discs developes rapidly and varies in accordance with the deformability, ITSs of curing materials were not found convenient to determine under the loading apparatus with indefinite contact angle. ITS values increasing with an increase in contact angle can be measured to be excessively high because of the high contact angles resulted from the deformable characteristics of the soft paste backfill materials. As a result of the change of deformation characteristics with the change of curing time, discs have different contact conditions causing an important disadvantage to reflect the strength change due to the curing reactions. In addition to the experimental study, finite element analyses were performed on several types of disc models under various loading conditions. As a result, a comparison between all loading conditions was made to determine the best ITSs of the cemented paste backfill materials. Both experimental and numerical analyses concluded that loading arcs with definite contact angles gives better results than those obtained with the other loading apparatus without a definite contact angle. Loading arcs with the contact angle of $15^{\circ}$ was found the most convenient loading apparatus for the typical cemented paste backfill materials, although it should be used carefully considering the failure cracks for a valid test.