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검색결과 3,287건 처리시간 0.039초

Direct Search Methods for Nonlinear Optimization Problem used ART Theory

  • 손준혁;서보혁
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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    • pp.1830-1831
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    • 2006
  • In this paper, the search is conducted along each of the coordinate directions for finding the minimum. If $e_i$ is the unit vector along the coordinate direction i, we determine the value a, minimizing f(a)= $f(x+ae_i)$, where a is a real number. A move is made to the new point $x+a_ie_i$ at the end of the search along the direction i. In an n dimensional problem, we define the search along all the directions as one stage. The function value at the end of the stage is compared to the value at the beginning of the stage in establishing the convergence. The gradient appears to be zero at point. We can safeguard this by introducing an acceleration step of one additional step along the pattern direction developed by moves along the coordinate directions.

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Development of parked vehicles searching system

  • Lim, Do-Hyung;Seo, Chang-Jun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.1464-1467
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    • 2005
  • In this research, we developed a system, which can find the location of vehicle when people park their cars in a big parking lot or large area. People can find their cars readily through this simple device and they can save their time and effort. This is the purpose of this research. Performing this, detection of electromagnetic wave's direction is needed and we used shielding effectiveness of electromagnetic waves for the method of it. An absolute coordinate indicates four directions (E, W, S, N) by using an electronic compass module, and it is needed for the localization. The device can check the received count of the electromagnetic waves coming from all other directions through the system, which is installed in the vehicle. The direction recorded the least received count would be the location of the parked vehicles. We can add on the function of this research by using the same frequency of cars alarm goods. Also, it is useful in the huge indoor parking lot.

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소형 비행체 탑재를 위한 크기 비교용 방향 탐지 안테나 조립체 (An Amplitude Comparison Direction-Finding Antenna Assembly for Mounting on a Small Flight Vehicle)

  • 김재식
    • 한국군사과학기술학회지
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    • 제23권5호
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    • pp.459-465
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    • 2020
  • In this paper, a compact antenna assembly for an amplitude comparison direction-finding(DF) method for a small flight vehicle is presented. Designed antenna assembly consists of four antennas and it is mounted on a radius of 1.45 λc where λc corresponds to the wavelength of the center frequency. To achieve compactness and robustness of the assembly, the elements are fed by end-launch feeding method and have modified aperture shapes of E- or H-sectoral horns. The feeding part consists of SMA connector, stepped impedance matching structure, and square waveguide of 0.6 λc × 0.6 λc. To achieve different main beam directions for every antenna which is required condition for amplitude comparison DF method, all apertures of the antennas are inclined and it makes the main beam direction of each antenna to top, bottom, left, and right with respect to the axis of the platform. To verify the validation of DF performance of the presented antenna assembly, amplitude comparison curves using measurement results are presented. The bandwidth of the antennas are above 3.2 % in Ku-band(VSWR ≤ 2:1).

하악골 운동시 과두의 이동범위에 관하여 (THE NORMAL RANGE OF CONDYLAR MOVEMENT)

  • 최한업
    • 치과방사선
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    • 제8권1호
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    • pp.43-47
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    • 1978
  • The purpose of this study was to investigate the normal range of condylar movement of normal adults. The author has observed roentgenographic images of four serial positions of condylar head taken by modified transcranail lateral oblique projection. The serial positions are centric occlusion, rest position, 1 inch open position and maximal open position. The results were obtained as follow; 1. Inter-incisal distance was 46.85㎜ in maximal open position. 2. The length between the deepest point of glenoid fossa and summit of condylar head in rest position was wider than that in centric occlusion by 0.8㎜. 3. In 1 inch open position, condylar head moved forward from the standard line in 12.64㎜ of horizontal direction and moved downwards from the standard line in 1.84㎜ of vertical direction. 4. In maximal open position, condylar head moved forward from the standard line in 19.06㎜ of horizontal direction and moved downwards from thestanard line in 0.4㎜ of vertical direction. 5. In centric occlusion, the width between glenoid fossa and margin of condylar head was greater in the posterior portion than in the anterior portion by 0.4㎜. 6. Except for the estimated figures of 1 inch open position, all of the estimated figures was greater in male than in female.

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조류 흐름을 고려한 해양지반 수리저항성능 실험기 개발 (Development of Apparatus for Measuring Hydraulic Resistance of Sea Ground Considering Tidal Current Flow)

  • 강경오;정현철;김영상
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 추계 학술발표회
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    • pp.1366-1369
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    • 2010
  • Along with the increasing need of sea development, the hydraulic stability of seabed structure on a soft seafloor ground is becoming an issue in the course of seaside development recently. However, the movement and hydraulic resistance or hydraulic stability of seafloor ground are mutually coupled with various phenomena, and there has been no clear proof for the issue, which makes it difficult to forecast. Furthermore, most researches are focused on hydraulic variables and the conditions of marine external force, while there have been few researches into the assessment in consideration of the type of a seafloor ground and the geotechnical characteristics. In addition, according to the periodic change of the flow direction, possible changes in hydraulic resistance performance of the seafloor deserves all the recognition. But there is no way to measure the hydraulic unstability of the sea ground due to tidal flow quantitatively. In this study, conventional hydraulic resistance measurement apparatus was improved to consider direction change of the current flow. Various artificial clayey soil specimens were made from Kaolinite and Jumunjin standard sand and hydraulic resistance tests were performed by changing the flow direction to validate the effect of the direction change on the scour of the seafloor.

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Effect of Action Observation Training Using Y-Balance on Balance Capability in Young Adults

  • Son, Sung Min;Kang, Kyung Woo
    • The Journal of Korean Physical Therapy
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    • 제32권2호
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    • pp.65-69
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    • 2020
  • Purpose: This study examined the effects of action-observation training using the Y-Balance on the balance ability of young adults. Methods: Thirty-four healthy adults were randomized into an action-observation group (n=17) or a control group (n=17). All subjects performed the Y-Balance test before and after watching the video. The action observation group watched a video of someone performing a Y-Balance test, and the control group watched a video of scenery unrelated to the training. The subjects were measured through a Y-Balance test for both the length of the legs extended in three directions and the Y-balance composite score. Results: A significant difference in the Y-balance composite score was observed between the two groups. A part of the direction of the extended leg in the action observation group was increased significantly (posteromedial direction of the right leg, posterolateral direction of the right leg, posteromedial direction of left leg) compared to the control group. Conclusion: These results suggest that action observation training only could help improve balance.

UR 대비 수산정책의 과제와 방향 (Fisheries Policy in Korea after the Conclusion of the Uruguay Round Negotiations : Its Problem and Direction)

  • 최정윤
    • 수산해양교육연구
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    • 제6권2호
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    • pp.93-116
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    • 1994
  • This paper aims to explain the direction of a long-range policy for the development of fisheries industry and fishing villages in Korea after the Conclusion of the Uruguay Round Negotiations. When the Uruguay Round Negotiations were concluded last year, the government soon set up the Committee of Farming and Fishing Village Development under the direct control of the President and launched on the development of agriculture and fisheries policy to provide for the post-Uruguay Round. The Committee drew up an all-round policy report, "The Problem and Direction of Agriculture Policy Reform" as a result of the six-month activity of this committee from February through July, 1994 in which the author participated, and presented it to the President. The author rearranged the problems of a long-range policy related to fisheries industry and fishing villages apart from this report, and drew up another report under the title, "Fisheries Policy in Korea after the Conclusion of the Uruguay Round Negotiations : Its Problem and Direction," which was reported at the year 1994 autumn symposium of the Korean Pedagogic Society of Fisheries and Marine Sciences.

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양방사선 골밀도 측정 장치의 공간산란선량분포측정 (Bone Density Spatial Distribution of Radiation Dose Measurement)

  • 김선칠;원도연;박창희;동경래
    • 대한디지털의료영상학회논문지
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    • 제13권2호
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    • pp.59-62
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    • 2011
  • In this experiment, how DEXA(Dual-energy X-ray Absorptiometry) bone mineral density was measured using the equipment. In order to maintain the same measurement conditions, bone mineral density measurements of 10 cm thick phantom, with an actual patient at a point when examining the same conditions(100 kVp, 1 mA) and then out to the five doses of radiation and its average was calculated by dividing measured. X-ray dose rate measured at the Research Institute, Sword of the gamma survey meters calibrated MEDCOM Ltd. (Inspector GM counter tube) was used, calibration factor is 1.15. On a horizontal plane around the patient, depending on the distance was significantly reduced dose rate. In addition, orientation $0^{\circ}$ head end was higher in the direction of the highest dose rate, $0^{\circ}$ $180^{\circ}$ direction from the direction towards the higher dose rate reduced to some extent in the direction of all the $120^{\circ}$ were able to identify.

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래티스돔의 지진 하중 방향에 따른 지진 응답 분석 (The Seismic Response Analysis of Lattice Dome According to Direction of Seismic Load)

  • 김유성;강주원;김기철
    • 한국공간구조학회논문집
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    • 제18권3호
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    • pp.133-140
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    • 2018
  • Vertical earthquake motions can occur along with horizontal earthquakes, so that Structure should be designed to resist Seismic loads in all directions. Especially, due to the dynamic characteristics such as the vibration mode, when the vertical seismic load, the dynamic response of the Spatial structure is large. In this study, the seismic response of the lattice dome to horizontal and vertical seismic loads is analyzed, and a reasonable seismic load combination is analyzed by combining horizontal and vertical seismic response results. In the combination of the horizontal seismic load, the largest result is obtained when the direction of the main axis of the structure coincides with the direction of seismic load. In addition, the combination of vertical seismic load and horizontal seismic load was the largest compared with the combination of horizontal seismic load. Therefore, it is considered that the most reasonable and stable design will be achieved if the seismic load in vertical direction is considered.

초음파 속도를 이용한 Type 316LN 스테인리스 강의 크리프 손상 평가 (Evaluation of the creep damage of the Type 316LN stainless steel by the ultrasonic wave velocity)

  • 이원;노경용;윤송남;김우곤
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 추계학술대회 논문집
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    • pp.818-823
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    • 2005
  • Creep damage is one of the mosl important characteristics for the stability of high temperature structures such as huge energy converting facilities. Creep failure of Type 316LN stainless steel is highly correlated to generation and growth of the voids. In this paper, in order to investigate the correlation of creep rupture time and ultrasonic parameters (group velocity, angular velocity), creep-damaged Type 316LN specimens and measurements for the ultrasonic parameters were made. However, bi-directional measurements were applied along the load direction and the perpendicular direction to the load line by means of the contact type probe of which the central frequencies are 10MHz, 15MHz and 20MHz. Analyzing the angular velocities of the ultrasonic signals obtained from the load direction, it was confirmed that the angular velocities were declined as the creep time passed when 15MHz and 20MHz probes were used. Also, the group velocities were declined for all three frequencies as the creep time increased. Thus, positive feasibility for the creep damage evaluation by means of the angular and group velocities was confirmed. Moreover, result of analysis for the ultrasonic signal which was obtained from the perpendicular direction upon the angular and group velocities indicated little variation for both of the angular and group velocities. Therefore, the creep damage is likely to represent anisotropic itself.

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