• Title/Summary/Keyword: pointing method

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Method of Quasi-Three Dimensional Stability Analysis of the Root Pile System on Slope Reinforcement (사면보강 뿌리말뚝공법의 준3차원적 안정해석기법)

  • Kim, Hong-Taek;Gang, In-Gyu;Park, Sa-Won
    • Geotechnical Engineering
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    • v.13 no.5
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    • pp.101-124
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    • 1997
  • The root pile system is insitu soil reinforcement technique that uses a series of reticulately installed micropiles. In terms of mechanical improvement by means of grouted reinform ming elements, the root pile system is similar to the soil nailing system. The main difference between root piles and soil nailing are due to the fact that the reinforcing bars in root piles are normally grouted under high pressure and that the alignments of the reinforcing members differ. Recently, the root pile system has been broadly used to stabilize slopes and retain excavations. The accurate design of the root pile system is, however, a very difficult tass owing to geometric variety and statical indetermination, and to the difficulty in the soilfiles interaction analysis. As a result, moat of the current design methods have been heavily dependent on the experiences and approximate approach. This paper proposes a quasi-three dimensional method of analysis for the root pile system applied to the stabilization of slopes. The proposed methods of analysis include i) a technique to estimate the change in borehole radium as a function of the grout pressure as well as a function of the time when the grout pressure is applied, ii) a technique to evaluate quasi -three dimensional limit-equilibrium stability for sliding, iii) a technique to predict the stability with respect to plastic deformation of the soil between adjacent root piles, and iv) a quasi -three dimensional finite element technique to compute stresses and dis placements of the root pile structure barred on the generalized plane strain condition and composite unit cell concept talon형 with considerations of the group effect and knot effect. By using the proposed technique to estimate the change in borehole radius as a function of the grout pressure as well as a function of the time, the estimations are made and compar ed with the Kleyner 8l Krizek's experimental test results. Also by using the proposed quasi-three dimensional analytical method, analyses have been performed with the aim of pointing out the effects of various factors on the interaction behaviors of the root pile system.

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Analysis of KVN 21m Radio Antenna Optics using Ray-Tracing Method (광선추적방법을 이용한 KVN 21m 전파망원경 광학계의 해석)

  • Bae, Jae-Han;Byun, Do-Young
    • Journal of Astronomy and Space Sciences
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    • v.26 no.2
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    • pp.187-198
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    • 2009
  • In this work, we calculate drop in antenna gain, aperture phase distribution, and antenna pointing shift of KVN(Korean VLBI Network) 21m shaped Cassegrain antenna due to misalignments of antenna optics using ray-tracing method. The misalignments we considered are axial displacement of feed, axial displacement of sub-reflector, lateral displacement of feed, lateral displacement of sub-reflector, and sub-reflector tilt. Calculations are performed not only when these misalignments exist separately, but also when they exist at the same time. Although ray-tracing method is based on geometric optics which does not consider electromagnetic effects, we expect that this work enables us to align antenna optics which give the maximum gain.

Dial Menu User Interface Using Touch Screen (터치스크린을 이용한 다이얼 메뉴 유저 인터페이스)

  • Choi, Jung-Hwan;Kim, Youn-Woo;Jang, Hyun-Su;Eom, Young-Ik
    • 한국HCI학회:학술대회논문집
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    • 2008.02a
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    • pp.584-589
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    • 2008
  • The in put system using the touch screen directly makes the input signals by the contact on the screen without the assistance of peripherals such as a pen or hands. These kinds of input systems using the flexible hands is maximizing suppleness and intuition of the input rather than those systems using a keyboard or a mouse which are moving a cursor or typing a word. However, using hands for an input may give rise to a mistake in control. And there are few interfaces utilizing the touch screen. Incorrectness and insufficiency of the interface are the weak point of the touch screen systems. In this paper, we propose the dial menu user interface for the mobile devices using touch screen for an efficient input. In this method, it consists of 2 states(Inactive states, Active states) and 4 actions(Rotation, Zoom in, and Zoom out, and Click). The intuitive control utilizing the suggested method overcomes the incorrect pointing, weak point of the touch screen system, and boosts the searching menu by utilizing the drag function of the touch screen.

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Wearable User Interface based on EOG and Marker Recognition (EOG와 마커인식을 이용한 착용형 사용자 인터페이스)

  • Kang, Sun-Kyoung;Jung, Sung-Tae;Lee, Sang-Seol
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.6 s.44
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    • pp.133-141
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    • 2006
  • Recently many wearable computers have been developed. But they still have many user interface problems from both an input and output perspective. This paper presents a wearable user interface based on EOG(electrooculogram) sensing circuit and marker recognition. In the proposed user interface, the EOG sensor circuit which tracks the movement of eyes by sensing the potential difference across the eye is used as a pointing device. Objects to manipulate are represented human readable markers. And the marker recognition system detects and recognize markers from the camera input image. When a marker is recognized, the corresponding property window and method window are displayed to the head mounted display. Users manipulate the object by selecting a property or a method item from the window. By using the EOG sensor circuit and the marker recognition system, we can manipulate an object with only eye movement in the wearable computing environment.

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Development of Fuzzy Logic-based MPPT and Performance Verification through EBA for Satellite Applications (퍼지 로직 기반의 위성용 MPPT 개발 및 EBA를 통한 성능검증)

  • Yeom, Seung-Yong;Park, Ki-Yun;Kim, Hong-Rae;Chang, Young-Keun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.9
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    • pp.779-788
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    • 2014
  • The satellite should generate electric power efficiently to perform the mission successfully within limited power. For this reason, the electrical power system of LEO satellites usually regulates the power which is generated from the solar cells using MPPT (Maximum Power Point Tracking) method. This paper proposes advanced MPPT algorithm based on the fuzzy logic applied to small CubeSat satellite. The simulation has been performed to confirm the validity of the proposed method by interlocking between MATLAB/Simulink and STK (Systems Tool Kit). The EBA(Energy Balance Analysis) has also been performed at two different pointing modes of KAUSAT-5 for solar irradiation according to the satellite orbit and attitude, and load capacity varied with operation modes by Simulink and STK. The performance of fuzzy logic-based MPPT algorithm was verified through the EBA. The validity of the proposed MPPT algorithm based on the fuzzy logic was also confirmed by comparing with P&O (Perturbation & Observation) algorithm that is general in the MPPT.

Effect of System Instability Factors in a Bistatic MTI Radar Using Pulse Chasing Scan Method (펄스 체이싱 스캔 방식을 이용한 바이스태틱 MTI 레이더에서 시스템 불안정 요소들의 영향)

  • Yang, Jin-Mo;Han, Il-Tak;Lee, Yong-Suk;Lee, Min-Joon;Kim, Whan-Woo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.3
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    • pp.299-311
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    • 2011
  • In this paper, we have identified the system instability factors in a bistatic radar system using pulse chasing and considered their effects on the bistatic receiver's MTI(Moving Target Indication) improvement performance. The pulse chasing is a scan method that searchs a restricted area on the transmit pulse-to-pulse basis and the MTI filter is a signal processing that separates a target from some kinds of interferences such as clutter using small number of transmit pulses. Ideal MTI processing performance, e.g., clutter attenuation and improvement, has been limited by the property of the clutter itself, however, the MTI performance in a proposed bistatic receiver configuration could be affected by the receiving beam pointing error during pulse chasing scanning. Also, for the bistatic receiver, we have defined other system instability factors, which result from the time synchronization error, COHO's phase error, the frequency/phase synchronization error, and have analyzed their effects on the system performance improvement.

Preliminary Orbit Determination For A Small Satellite Mission Using GPS Receiver Data

  • Nagarajan, Narayanaswamy;Bavkir, Burhan;John, Ong Chuan Fu
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.141-144
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    • 2006
  • The deviations in the injection orbital parameters, resulting from launcher dispersions, need to be estimated and used for autonomous satellite operations. For the proposed small satellite mission of the university there will be two GPS receivers onboard the satellite to provide the instantaneous orbital state to the onboard data handling system. In order to meet the power requirements, the satellite will be sun-tracking whenever there is no imaging operation. For imaging activities, the satellite will be maneuvered to nadir-pointing mode. Due to such different modes of orientation the geometry for the GPS receivers will not be favorable at all times and there will be instances of poor geometry resulting in no output from the GPS receivers. Onboard the satellite, the orbital information should be continuously available for autonomous switching on/off of various subsystems. The paper presents the strategies to make use of small arcs of data from GPS receivers to compute the mean orbital parameters and use the updated orbital parameters to calculate the position and velocity whenever the same is not available from GPS receiver. Thus the navigation message from the GPS receiver, namely the position vector in Earth-Centered-Earth-Fixed (ECEF) frame, is used as measurements. As for estimation, two techniques - (1) batch least squares method, and (2) Kalman Filter method are used for orbit estimation (in real time). The performance of the onboard orbit estimation has been assessed based on hardware based multi-channel GPS Signal simulator. The results indicate good converge even with short arcs of data as the GPS navigation data are generally very accurate and the data rate is also fast (typically 1Hz).

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Development of Homogeneous Road Section Determination and Outlier Filter Algorithm (국도의 동질구간 선정과 이상치 제거 방법에 관한 연구)

  • Do, Myung-Sik;Kim, Sung-Hyun;Bae, Hyun-Sook;Kim, Jong-Sik
    • Journal of Korean Society of Transportation
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    • v.22 no.7 s.78
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    • pp.7-16
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    • 2004
  • The homogeneous road section is defined as one consisted of similar traffic characteristics focused on demand and supply. The criteria, in the aspect of demand, are the diverging rate and the ratio of green time to cycle time at signalized intersection, and distance between the signalized intersections. The criteria, in that or supply, are the traffic patterns such as traffic volume and its speed. In this study, the effective method to generate valuable data, pointing out the problems of removal method of obscure data, is proposed using data collected from Gonjiam IC to Jangji IC on the national highway No.3. Travel times are collected with licence matching method and traffic volume and speed are collected from detectors. Futhermore, the method of selecting homogeneous road section is proposed considering demand and supply aspect simultaneously. This method using outlier filtering algorithm can be applied to generate the travel time forecasting model and to revise the obscured of missing data transmitting from detectors. The point and link data collected at the same time on the rational highway can be used as a basis predicting the travel time and revising the obscured data in the future.

Robust Design of the Vibratory Gyroscope with Unbalanced Inner Torsion Gimbal Using Axiomatic Design (공리적 설계를 이용한 비대칭 내부 짐벌을 가진 진동형 자이로스코프의 강건설계)

  • Park, Gyeong-Jin;Hwang, Gwang-Hyeon;Lee, Gwon-Hui;Lee, Byeong-Ryeol;Jo, Yong-Cheol;Lee, Seok-Han
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.5
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    • pp.914-923
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    • 2002
  • Recently, there has been considerable interest in micro gyroscopes made of silicon chips. It can be applied to many micro-electro-mechanical systems (MEMS): devices for stabilization, general rate control, directional pointing, autopilot systems, and missile control. This paper shows how the mechanical design of the gyroscope can be done using axiomatic design, followed by the application of the Taguchi robust design method to determine the dimensions of the parts so as to accommodate the dimensional variations introduced during manufacturing. Functional requirements are defined twofold. One is that the natural frequencies should have fixed values, and the other is that the system should be robust to large tolerances. According to the Independence Axiom, design parameters are classified into a few groups. Then, the detailed design process is performed fellowing the sequence indicated by the design matrix. The dimensions of the structure are determined to have constant values fur the difference of frequencies without consideration of the tolerances. It is noted that the Taguchi concept is utilized as a unit process of the entire axiomatic approach.

Determination of the Location of a Line Source using Gravity Gradient Tensor (중력 변화율 텐서를 이용한 선형 이상체 위치 결정)

  • Park, Changseok;Rim, Hyoungrea
    • Journal of the Korean earth science society
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    • v.38 no.4
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    • pp.263-268
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    • 2017
  • The determination algorithm of the location of a line source with strike and dip using the gravity gradient tensor on a single profile is proposed. We already proposed the determination of strike and dip in the previous paper and then, now we improved the algorithm to locate a line source after determining strike and dip. The strike and dip of the line source can be determined by rotating the gravity gradient tensor matrix as reducing 2 independent components. Using the ratio of remaining 2 components, the location can be determined by the least square manner of the pointing vectors on each observation point. A synthetic model is tested for proving the usefulness of the proposed algorithm.