• 제목/요약/키워드: Experimental Design Technique

검색결과 1,033건 처리시간 0.023초

모바일 응용에서 이동 객체의 궤적-기반 질의를 위한 색인 구조 (An Index Structure for Trajectory-based Query of Moving Objects in Mobile Applications)

  • 심춘보;주재흠
    • 한국정보통신학회논문지
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    • 제8권8호
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    • pp.1828-1834
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    • 2004
  • 무선 통신 및 모바일 기술의 급속한 발전으로 인해 위치 기반 서비스 및 모바일 응용 서비스와 같은 이동 객체에 기반한 다양한 서비스에 대한 요구가 증가하게 되었다. 이를 위해, 본 논문에서는 모바일 응용에서 이동 객체에 대한 다양한 질의 중에서 특히 궤적-기반 질의에 대한 성능을 향상시킬 수 있는 색인 구조를 제안한다. 제안하는 색인 구조는 이동 객체의 궤적-기반 질의를 위해 제안되었던 기존의 TB-tree의 삽입 및 검색 성능의 효율성을 높이기 위해 연결테이블(LinkTable:L-Table)을 유지한다. L-Table은 선행 노드를 한번에 직접 접근하기 위해 이동 객체의 처음 세그먼트와 마지막 세그먼트가 저장된 단말 노드를 가리키는 포인터 정보와 디스크에서의 페이지를 가리키는 페이지 번호를 저장한다. 아울러 시스템의 가용메모리가 제약을 받는 경우에도 일정한 크기의 버퍼를 유지해 색인의 일부만을 메모리에 상주시킬 수 있도록 설계한다. 마지막으로 제안하는 색인 구조의 성능을 평가하기 위하여 다양한 실험 데이타를 이용해 성능 평가를 수행한 결과, 삽입 및 궤적-기반 질의 측면에서 기존의 색인 구조들에 비해 더 나은 성능을 보인다.

A Study on the Measurement for the Nano Scale Film Formation of Ultra Low Aspect Ratio

  • Jang Siyoul;Kong Hyunsang
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2004년도 학술대회지
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    • pp.283-288
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    • 2004
  • The measurement of ultra low aspect ratio fluid film thickness is very crucial technique both for the verification of lubrication media characteristics and for the clearance design in many precision components such as MEMS, precision bearings and other slideways. Many technologies are applied to the measurement of ultra low aspect ratio fluid film thickness (i.e. elastohydrodynamic lubrication film thickness). In particular, in-situ optical interferometric method has many advantages in making the actual contact behaviors realized with the experimental apparatus. This measurement method also does the monitoring of the surface defects and fractures happening during the contact behavior, which are delicately influenced by the surface conditions such as load, velocity, lubricant media as well as surface roughness. Careful selection of incident lights greatly enhances the fringe resolutions up to $\~1.0$ nanometer scale with digital image processing technology. In this work, it is found that coaxial aligning trichromatic incident light filtering system developed by the author can provide much finer resolution of ultra low aspect ratio fluid film thickness than monochromatic or dichromatic incident lights, because it has much more spectrums of color components to be discriminated according the variations of film thickness. For the measured interferometric images of ultra low aspect ratio fluid film thickness it is shown how the film thickness is finely digitalized and measured in nanometer scale with digital image processing technology and space layer method. The developed measurement system can make it possible to visualize the contact deformations and possible fractures of contacting surface under the repeated loading condition.

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Debonding failure analysis of FRP-retrofitted concrete panel under blast loading

  • Kim, Ho Jin;Yi, Na Hyun;Kim, Sung Bae;Nam, Jin Won;Ha, Ju Hyung;Kim, Jang-Ho Jay
    • Structural Engineering and Mechanics
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    • 제38권4호
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    • pp.479-501
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    • 2011
  • Even though fiber reinforced polymer (FRP) has been widely used as a retrofitting material, the FRP behavior and effect in FRP retrofitted structure under blast loading, impulsive loading with instantaneous time duration, has not been accurately examined. The past studies have focused on the performance of FRP retrofitted structures by making simplifications in modeling, without incorporating accurate failure mechanisms of FRP. Therefore, it is critical to establish an analytical model that can properly consider the specific features of FRP material in evaluating the response of retrofitted concrete structures under blast loading. In this study, debonding failure analysis technique for FRP retrofitted concrete structure under blast loading is suggested by considering FRP material characteristics and debonding failure mechanisms as well as rate dependent failure mechanism based on a blast resisting design concept. In addition, blast simulation of FRP retrofitted RC panel is performed to validate the proposed model and analysis method. For validation of the proposed model and analysis method, the reported experimental results are compared with the debonding failure analysis results. From the comparative verification, it is confirmed that the proposed analytical model considering debonding failure of FRP is able to reasonably predict the behavior of FRP retrofitted concrete panel under blast loading.

충동형 터빈 캐스케이드의 깃 하중 측정에 관한 연구 (A Study on the Blade Load Measurement of Partial-admission Turbine Cascade)

  • 임동화;정진만;이은석;김진한;최종수
    • 한국항공우주학회지
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    • 제35권2호
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    • pp.143-148
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    • 2007
  • 액체 추진 로켓을 구동하는 충동형 터빈은 크기가 작고 가벼워야 하며 큰 출력을 발생시켜야 한다. 충동형 터빈은 초음속 조건에서 작동되기 때문에 유동 특성이 매우 복잡하여 성능 예측은 주로 수치해석에 의존해 왔다. 그러나 신뢰성을 확보하기 위하여는 해석결과를 실험으로 검증하는 과정이 필요하다. 본 연구에서는 설계에 사용되는 주요 변수들의 영향을 확인하기 위하여 회전하는 3차원 축류 터빈을 2차원 형상으로 모사하여 실험하였다. 먼저 노즐 출구에서의 마하수를 측정하였으며, 이론적인 노즐 추력식을 유도하여 터빈 블레이드에 작용하는 깃하중을 계산하였고 측정된 결과와 비교하였다. 또한 추력 계수를 구하고 이를 통해 터빈 출력을 예측하여 설계 요구 조건의 타당성을 확인하였다

미세유체칩내 electrode의 opening window형태에 따른 유전전기영동력 특성 규명 (Characterization of Dielectrophoretic Force for the Structural Shapes of Window in Microfluidic Dielectrophoretic Chip)

  • 이재우;곽태준;윤대성;이상우
    • 대한의용생체공학회:의공학회지
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    • 제34권4호
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    • pp.189-196
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    • 2013
  • Dielectrophoresis(DEP) is useful in manipulation and separation of micro-sized particles including biological samples such as bacteria, blood cells, and cancer cells in a micro-fluidic device. Especially, those separation and manipulation techniques using DEP in combination of micro fabrication technique have been researched more and more. Recently, it is revealed that a window structure of insulating layer in microfluidic DEP chip is key role in trap of micro-particles around the window structure. However, the trap phenomenon-driven by DEP force gradient did not fully understand and is still illusive. In this study, we characterize the trap mechanism and efficiency with different shapes of window in a microfluidic DEP chip. To do this characterization, we fabricated 4 different windows shapes such as rhombus, circle, squares, and hexagon inside a micro-fluidic chip, and performed micro-sized particles manipulation experiments as varying the frequency and voltage of AC signal. Moreover, the numerical simulation with the same parameters that were used in the experiment was also performed in order to compare the simulation results and the experimental results. Those comparison shows that both results are closely matched. This study may be helpful in design and development of microfluidic DEP chip for trapping micro-scaled biological particle.

타임 윈도우 기반의 T-N2SCD 탐지 모델 구현 (Design of T-N2SCD Detection Model based on Time Window)

  • 신미예;원일용;이상호
    • 한국정보통신학회논문지
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    • 제13권11호
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    • pp.2341-2348
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    • 2009
  • 호스트 기반 침입탐지 기법에는 시스템 호출 순서를 고려하는 방법과 시스템 호출 파라미터를 고려하는 방법이 있다. 이 두 방법은 프로세스의 시스템 호출이 일어나는 전 구간에서 시스템 호출 순서에 이상이 있거나 시스템 호출 파라미터의 순서 및 길이 등에 이상이 있는 경우에 적합하지만 긍정적 결함율과 부정적 결함율이 높은 단점이 있다. 이 논문에서는 시스템 호출을 이용한 방법에서 발생하는 긍정적 결함율과 부정적 결함율을 줄이기 위해서 단위 시간을 도입한 타임 윈도우 기반의 T-N2SCD 탐지 모델을 제안한다. 제안 모델의 실험에 사용된 데이터는 DARPA에서 제공된 데이터이며, 실험 결과 제안 모델은 다른 시간 간격 보다 1000ms 시간 간격으로 실험하였을 경우가 긍정적 결합률과 부정적 결합률이 가장 낮았다.

Improvement of Dynamic Behavior of Shunt Active Power Filter Using Fuzzy Instantaneous Power Theory

  • Eskandarian, Nasser;Beromi, Yousef Alinejad;Farhangi, Shahrokh
    • Journal of Power Electronics
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    • 제14권6호
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    • pp.1303-1313
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    • 2014
  • Dynamic behavior of the harmonic detection part of an active power filter (APF) has an essential role in filter compensation performances during transient conditions. Instantaneous power (p-q) theory is extensively used to design harmonic detectors for active filters. Large overshoot of p-q theory method deteriorates filter response at a large and rapid load change. In this study the harmonic estimation of an APF during transient conditions for balanced three-phase nonlinear loads is conducted. A novel fuzzy instantaneous power (FIP) theory is proposed to improve conventional p-q theory dynamic performances during transient conditions to adapt automatically to any random and rapid nonlinear load change. Adding fuzzy rules in p-q theory improves the decomposition of the alternating current components of active and reactive power signals and develops correct reference during rapid and random current variation. Modifying p-q theory internal high-pass filter performance using fuzzy rules without any drawback is a prospect. In the simulated system using MATLAB/SIMULINK, the shunt active filter is connected to a rapidly time-varying nonlinear load. The harmonic detection parts of the shunt active filter are developed for FIP theory-based and p-q theory-based algorithms. The harmonic detector hardware is also developed using the TMS320F28335 digital signal processor and connected to a laboratory nonlinear load. The software is developed for FIP theory-based and p-q theory-based algorithms. The simulation and experimental tests results verify the ability of the new technique in harmonic detection of rapid changing nonlinear loads.

30CMM급 태양기공 전기집진 설비의 실내분진 정화 능력에 관한 실험연구 (An Experimental Study of 30CMM Solar Transpired Collector and Cyclone(STCC) System on Indoor Air Dust Removal Performance)

  • 노지희;박상현;강은철;이의준
    • 한국태양에너지학회 논문집
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    • 제25권3호
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    • pp.37-45
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    • 2005
  • Higher requirement of advanced building design code and the development of construction technique have resulted in more thermal and air tight buildings. This has caused the sick building syndrome in a indoor air quality has been relatively getting worse. A new concept with a solar fresh air heating and electrostatic precipitator or called as STCC(Solar Transpired Collector and Cyclone) has been proposed to solve this IAQ issue. This paper describes the assessment study of STCC system under different outdoor airflow rates. The experiment was carried out under real condition with 30CMM STCC system test facility. Incense smoke was used to study the particle concentration decay trends under outdoor airflow rates 0CMM, 10CMM, 20CMM, 30CMM, with applied voltages of 5kV and 15kV for collecting and discharging electrodes of an Electrostatic Precipitator. Result shows that the particle decay increases by increasing the outdoor airflow rates. The collection efficiency, dust cleaning effectiveness(P) and application area calculation result comparisons have also been studied. This factors could be used to estimate how a dust of indoor air quality(IAQ) and removed for a building space with a STCC system.

Single-axis Hardware in the Loop Experiment Verification of ADCS for Low Earth Orbit Cube-Satellite

  • Choi, Minkyu;Jang, Jooyoung;Yu, Sunkyoung;Kim, O-Jong;Shim, Hanjoon;Kee, Changdon
    • Journal of Positioning, Navigation, and Timing
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    • 제6권4호
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    • pp.195-203
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    • 2017
  • A 2U cube satellite called SNUGLITE has been developed by GNSS Research Laboratory in Seoul National University. Its main mission is to perform actual operation by mounting dual-frequency global positioning system (GPS) receivers. Its scientific mission aims to observe space environments and collect data. It is essential for a cube satellite to control an Earth-oriented attitude for reliable and successful data transmission and reception. To this end, an attitude estimation and control algorithm, Attitude Determination and Control System (ADCS), has been implemented in the on-board computer (OBC) processor in real time. In this paper, the Extended Kalman Filter (EKF) was employed as the attitude estimation algorithm. For the attitude control technique, the Linear Quadratic Gaussian (LQG) was utilized. The algorithm was verified through the processor in the loop simulation (PILS) procedure. To validate the ADCS algorithm in the ground, the experimental verification via a single axis Hardware-in-the-loop simulation (HILS) was used due to the simplicity and cost effectiveness, rather than using the 3-axis HILS verification (Schwartz et al. 2003) with complex air-bearing mechanism design and high cost.

자가간호에 관한 연구동향 및 명제분석 (An Analyses of Research Trend and Proposition Related to Self-care)

  • 강현숙;김원옥;현경선;조현숙;김정화;왕명자;백승남;원정숙;정연;석소현;이은미;장정미
    • 대한간호학회지
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    • 제28권4호
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    • pp.1013-1026
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    • 1998
  • This study was performed to analyse the tendency of the self-care studies, to investigate the variables related to self-care, which could be applied for the data establishing the theory of self-care. To accomplish the objectives of this study, the researchers analyzed 83 studies available that contained the area of self-care, which was published in local and foreign areas between 1981 and Feb. 1997. The findings of this study are as follows : 1) Studies published in Korea were about twice more than foreign studies. According to the statistics, the number of studies in this study tended to increase year by year. Between 1991 and 1995 were most. Analysis on the subject of those studies showed, that they were most dealt with chronic diseases an adaults. 2) The theoretical definition of self-care were most referred to Orem's self-care. For the main concept of studies, self care performance was the most. 3) The correlational study was most often used design and experimental study is tended to increase. The questionnares were the most often used data collection method. There was lots of different variable measuring technique to evaluate main concepts. 4) In the results of analysis on the propositions related to the self-care performance, a client's education, social support, self-efficacy, and level of knowledge as a causal variable were found. Also, the physiological index improved and quality of life were found to be significant effective variables.

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