• Title/Summary/Keyword: Path Compensation

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Mediating Effects of Self-leadership in the Relationship between Public Health Nurses' Organizational Culture and Their Job Performance (보건간호사의 조직문화와 업무성과 간의 관계: 셀프 리더십의 매개효과)

  • Park, Nam Hee;Lee, Kyung Jo;Lee, Sang Ju
    • Research in Community and Public Health Nursing
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    • v.28 no.1
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    • pp.23-33
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    • 2017
  • Purpose: The purpose of this research is to enhance organizational competitiveness of health centers as well as private medical institutions serving as public health and medical institutions. It tries to help them to cope with the requirements from health consumers, to enhance public health nurses' job performance, Methods: After verifying the reliability of the tool, confirmatory factor analysis was used to detect a model, in which valid path coefficients exist among variables. The detected model was then selected as the subject and its validity was verified. Finally, a structural equation model was applied to verify whether the estimate was suitable for the purpose of this research. Results: As for the nursing organizational culture, the public health nurses considered relation-oriented culture the most desirable. As for the self-leadership, they considered self-compensation the most desirable. It was found that mediating effects of self-leadership was partially significant. Conclusion: To enhance job performance, it is necessary to make a transition from the organizational culture to the relation-oriented culture and it is also necessary to develop a program capable of reinforcing self-leadership. In addition, it is necessary to conduct a research to verify whether such a developed self-leadership program is influential on job performance enhancement.

65 nm CMOS Base Band Filter for 77 GHz Automotive Radar Compensating Path Loss Difference (경로 손실 변화의 보상이 가능한 77 GHz 차량용 레이더 시스템을 위한 65 nm CMOS 베이스밴드 필터)

  • Kim, Young-Sik;Lee, Seung-Jun;Eo, Yun-Seong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.10
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    • pp.1151-1156
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    • 2012
  • In this paper, the baseband filter is proposed in order to maintain a constant sensitivity regardless of distances for 77 GHz automotive radar system. Using existing DCOC loop circuit can remove DC offset and also cancel differences of received power depending on the distance. Measured results show that the maximum gain is 51 dB and high pass cutoff frequency can be tuned from 5 kHz to 15 kHz. The slope of high pass filter can be tuned from -10 to -40 dB/decade for the distance compensation. The measured NF and IIP3 are 26 dB and +4.5 dBm with 4.3 mA at 1.0 V supply voltage, respectively. The fabricated die size $500{\mu}m{\times}1,050{\mu}m$ excluding the in/out pads.

Development of Autonomous Combine Using DGPS and Machine Vision (DGPS와 기계시각을 이용한 자율주행 콤바인의 개발)

  • Cho, S. I.;Park, Y. S.;Choi, C. H.;Hwang, H.;Kim, M. L.
    • Journal of Biosystems Engineering
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    • v.26 no.1
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    • pp.29-38
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    • 2001
  • A navigation system was developed for autonomous guidance of a combine. It consisted of a DGPS, a machine vision system, a gyro sensor and an ultrasonic sensor. For an autonomous operation of the combine, target points were determined at first. Secondly, heading angle and offset were calculated by comparing current positions obtained from the DGPS with the target points. Thirdly, the fuzzy controller decided steering angle by the fuzzy inference that took 3 inputs of heading angle, offset and distance to the bank around the rice field. Finally, the hydraulic system was actuated for the combine steering. In the case of the misbehavior of the DGPS, the machine vision system found the desired travel path. In this way, the combine traveled straight paths to the traget point and then turned to the next target point. The gyro sensor was used to check the turning angle. The autonomous combine traveled within 31.11cm deviation(RMS) on the straight paths and harvested up to 96% of the whole rice field. The field experiments proved a possibility of autonomous harvesting. Improvement of the DGPS accuracy should be studied further by compensation variations of combines attitude due to unevenness of the rice field.

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Flight trajectory generation through post-processing of launch vehicle tracking data (발사체 추적자료 후처리를 통한 비행궤적 생성)

  • Yun, Sek-Young;Lyou, Joon
    • Journal of Korea Society of Industrial Information Systems
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    • v.19 no.6
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    • pp.53-61
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    • 2014
  • For monitoring the flight trajectory and the status of a launch vehicle, the mission control system in NARO space center process data acquired from the ground tracking system, which consists of two tracking radars, four telemetry stations, and one electro-optical tracking system. Each tracking unit exhibits its own tracking error mainly due to multi-path, clutter and radio refraction, and by utilizing only one among transmitted informations, it is not possible to determine the actual vehicle trajectory. This paper presents a way of generating flight trajectory via post-processing the data received from the ground tracking system. The post-processing algorithm is divided into two parts: compensation for atmosphere radio refraction and multi-sensor fusion, for which a decentralized Kalman filter was adopted and implemented based on constant acceleration model. Applications of the present scheme to real data resulted in the flight trajectory where the tracking errors were minimized than done by any one sensor.

The Current-Position Cascade PID Control of Delta-type Parallel Robot (델타 로봇의 전류-위치 Cascade PID 제어)

  • Paek, Dong-Hee;Kim, Yeong-Dae;Cho, Whang
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.2
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    • pp.273-284
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    • 2020
  • This paper proposes a method of designing and controlling delta robots with low-cost DC motors, which are widely used in the automation process. Simulation was performed by interpreting the mechanics and dynamics of the delta robot, and based on this analysis, low-cost DC motor was selected. Experiments were conducted to obtain characteristic values of motors and the current-position cascade control system was designed and implemented. In order to verify the feasibility of the proposed system, the experiment to check that the end-effector of the delta robot follows the target path was progressed. Through the experiment, the limitations of using low-cost motors were overcome by designing compensation algorithms and the performance of the position control was verified.

A Method of ISAR Geometric Calibration for Point Target Using Impulse-Radio UWB (임펄스 초광대역 레이다를 이용한 점표적의 ISAR 기하 보정 방법)

  • Yu, Jiwoong;Nikitin, Konstantin;Paek, Inchan;Jang, Jong Hun;Ka, Min-Ho
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.4
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    • pp.397-403
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    • 2015
  • In this paper, a method of ISAR geometric calibration is represented by using impulse-radio UWB radar. The ir-UWB is good for using a signal processing in time domain, so, it does not occur a multi-path or coupling problem. If a signal that between antennas and target is assumed a plane wave, a center of rotation in ISAR geometry model can be estimated by using point target. Before image is reconstructed with sinogram, the center of rotation can be calculated by using least square fitting. This method can be obtained a more contrast image, and a maximum value of entropy of image. The method, that estimates a center of rotation in received data, will be used a initial setup of instruments or a periodic compensation to reconstruct image. It would be useful in medical, security and surveillance imaging equipments that have a fixed geometry.

An improvement algorithm for localization using adjacent node and distance variation analysis techniques in a ship (근접노드와 거리변화량분석기법을 이용한 선내 위치인식 개선 알고리즘)

  • Seong, Ju-Hyeon;Lim, Tae-Woo;Kim, Jong-Su;Park, Sang-Gug;Seo, Dong-Hoan
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.2
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    • pp.213-219
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    • 2013
  • Recently, with the rapid advancement in information and communication technology, indoor location-based services(LBSs) that require precise position tracking have been actively studied with outdoor-LBS using GPS. However, in case of a ship which consists of steel structure, it is difficult to measure a precise localization due to significant ranging error by the diffraction and refraction of radio waves. In order to reduce location measurement errors that occur in these indoor environments, this paper presents distance compensation algorithms that are suitable for a narrow passage such as ship corridors without any additional sensors by using UWB(Ultra-wide-band), which is robust to multi-path and has an error in the range of a few centimeters in free space. These improvement methods are that Pythagorean theory and adjacent node technique are used to solve the distance error due to the node deployment and distance variation analysis technique is applied to reduce the ranging errors which are significantly fluctuated in the corner section. The experimental results show that the number of nodes and the distance error are reduced to 66% and 57.41%, respectively, compared with conventional CSS(Chirp spread spectrum) method.

AC transport current loss analysis for anti-parallel current flow in face-to-face stacks of superconducting tapes

  • Yoo, Jaeun;Han, Young-Hee;Kim, Hey-Rim;Park, Byung-Jun;Yang, Seong-Eun;Kim, Heesun;Yu, Seung-Duck;Park, Kijun
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.2
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    • pp.42-46
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    • 2014
  • In this study we investigated ac transport current losses in the face to face stack for the anti-parallel current flow, and compared the electromagnetic properties with those of the single SC tape as well as those of the same stack for the parallel current path. The gap between the SC tapes in the stack varied in order to verify the electromagnetic influence of the neighbors when current flows in opposite direction, and the model was implemented in the finite element method program by the commercial software, COMSOL Multiphysics 4.2a. Conclusively speaking, the loss was remarkably decreased for the anti-parallel current case, which is attributed the magnetic flux compensation between the SC layers due to the opposite direction of the current flows. As the gap between SC tapes was increased, the loss mitigation became less effective. Besides, the current density distribution is very flat cross the sample width for the narrower gap case, which is believed to be benefit for the power electric system. These results are all in good agreement with those predicted theoretically for an infinite bifilar stack.

Micro cutting process technology for micro molds parts (마이크로 금형 부품을 위한 마이크로 절삭가공 기술)

  • Ha, Seok-Jae;Park, Jeong-Yeon;Kim, Gun-Hee;Yoon, Gil-Sang
    • Design & Manufacturing
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    • v.13 no.1
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    • pp.5-12
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    • 2019
  • In this paper, we studied the micro tool deflection, micro cutting with low temperature, and deformation of micro ribs caused by cutting forces. First, we performed an integrated machining error compensation method based on captured images of tool deflection shapes in micro cutting process. In micro cutting process, micro tool deflection generates very serious problems in contrast to macro tool deflection. To get the real images of micro tool deflection, it is possible to estimate tool deflection in cutting conditions modeled and to compensate for machining errors using an iterative algorithm correcting tool path. Second, in macro cutting fields, the cryogenic cutting process has been applied to cut the refractory metal but, the serious problem may be generated in micro cutting fields by the cryogenic environment. However, if the proper low temperature is applied to micro cutting area, the cooling effect of cutting heat is expected. Such effect can make the reduction of tool wear and burr formation. For verifying this passibility, the micro cutting experiment at low temperature was performed and SEM images were analyzed. Third, the micro pattern was deformed by the cutting forces and the shape error occurred in the sidewall multi-step cutting process were minimized. As the results, the relationship between the cutting conditions and the deformation of micro-structure during micro cutting process was investigated.

Improved Method to Select Targets in Phase Gradient Autofocus on Real Time Processing (실시간 처리를 위한 PGA 표적 선택기법 개선)

  • Lee, Hankil;Kim, Donghwan;Son, Inhye
    • The Journal of Korean Institute of Information Technology
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    • v.17 no.10
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    • pp.57-63
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    • 2019
  • Motion errors which are caused by several reasons, non-ideal path, errors of navigation systems, and radar system errors, have to be corrected. Motion compensation methods can compensate the motion error, but not exactly. To correct these residual errors, several autofocus methods are invented. A popular method is phase gradient autofocus (PGA). PGA does not assume specific circumstances, such as isolated point targets and shapes of errors. PGA is an iterative and adaptive method, so that the processing time is the main problem for the real time processing. In this paper, the improved method to select targets for PGA is proposed to reduce processing time. The variances of image pixels are used to select targets with high SNR. The processing of PGA with these targets diminishes the processing time and iterations effectively. The processed results with real radar data, obtained by flight tests, show that the proposed method compensates errors well, and reduce working time.