• Title/Summary/Keyword: gravity compensation

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The Khmer Rouge Genocide Trial and the Marcos Human Rights Victims: the Quest for Justice and Reparations

  • Mendoza, Meynardo P.
    • SUVANNABHUMI
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    • v.7 no.2
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    • pp.79-103
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    • 2015
  • Just how does one make sense of the genocide perpetrated by the Khmer Rouge during its rule in the 70's and the numerous human rights violations in the Philippines during the Marcos period? Like the conflicts that have marked human history at the close of the 20th century, Southeast Asia is no exception, similar to the many attempts to come to terms with the past and put to account wrongdoers worldwide. The paper is an attempt to historicize these two seemingly unrelated events and analyze them from the synoptic frameworks of transitional justice and reparations. Similar to the experiences faced by many societies transitioning towards democratic rule, notably in Latin America, the dilemma of whether to pursue justice or preserve the peace and the newfound status quo has characterized the length at which justice had eluded the victims in Cambodia and the Philippines. Yet, no matter what the limits are in pursuing accountability, or these so called historical injustices, closure is still achievable. The paper would like to argue that closure is possible when one, all or a combination of the following, depending on the gravity of the crime, is present-truth-telling, prosecution for the crimes committed, and a grant of compensation.

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The effect of managerial characteristics of franchisor on the perceived justice of franchisee (가맹본부의 관리적 특성이 창업 가맹점주의 공정성 인지도에 미치는 효과)

  • Kim, Gil-Sun;Ahn, Kwan-Young
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.7 no.2
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    • pp.157-165
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    • 2012
  • The specific gravity is heavily focused on the service industry in the economic development of domestic and overseas in these days. This will be predicted to increase persistently in the future society. Therefore the franchise system has been diffused as one of a management methods for these service industry. The franchise system is an advanced country's circulation system which has been populated in an advanced country. After the opening of circulation market, rapid growing trend has been showing on foreign country's popular brands in the local domestic market. So the franchise system has been largely focused on among the domestic manufacturing and the circulation companies. This study is to review how the management characteristics(headquarters' supports, communication, menu development, compensation) will affect the fairness perception of franchisee owner. The results of my study are as follows; It appeared that communication, menu development and compensation affected all the distribution fairness and the procedure fairness affirmatively.

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Lever Arm Compensation of Reference Trajectory for Flight Performance Evaluation of DGPS/INS installed on Aircraft (항공기에 탑재된 DGPS/INS 복합항법 장치의 비행 시험 성능 평가를 위한 기준궤적의 Lever Arm 보정)

  • Park, Ji-Hee;Lee, Seong-Woo;Park, Deok-Bae;Shin, Dong-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.12
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    • pp.1086-1092
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    • 2012
  • It has been studied for DGPS/INS(Differential Global Positioning System/Inertial Navigation System) to offer the more precise and reliable navigation data with the aviation industry development. The flight performance evaluation of navigation system is very significant because the reliability of navigation data directly affect the safety of aircraft. Especially, the high-level navigation system, as DGPS/INS, need more precise flight performance evaluation method. The performance analysis is performed by comparing between the DGPS/INS navigation data and reference trajectory which is more precise than DGPS/INS. The GPS receiver, which is capable of post-processed CDGPS(Carrier-phase DGPS) method, can be used as reference system. Generally, the DGPS/INS is estimated the CG(Center of Gravity) point of aircraft while the reference system is output the position of GPS antenna which is mounted on the outside of aircraft. For this reason, estimated error between DGPS/INS and reference system will include the error due to lever arm. In order to more precise performance evaluation, it is needed to compensate the lever arm. This paper presents procedure and result of flight test which includes lever arm compensation in order to verify reliability and performance of DGPS/INS more precisely.

Evaluation and Adjustment of Lateral Displacement of Complex-shaped RC Tall Buildings Considering the Displacement by Tilt Angle of Each Floor (층경사각에 의한 횡변위를 고려한 비정형 고층건물의 횡변위 평가/보정)

  • Kim, Yungon
    • Journal of the Korea Concrete Institute
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    • v.27 no.5
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    • pp.551-558
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    • 2015
  • Lateral displacement in the most complex-shaped tall buildings is caused by eccentric gravity loads which are induced by the difference in location between a center of mass and a center of stiffness. The lateral displacements obtained from analysis, using conventional procedures, are prone to overestimate the actual values because much of realignment efforts made during construction phase are ignored. In construction sequence analysis, the self-leveling of slab and the verticality of columns/walls could be considered at each construction stage. Moreover, the displacement compensation can be achieved by manual process such as re-centering - locating to global coordinates through surveying. Because the lateral displacement increases with the building height, it is necessary to set up adjustment plan through construction stage analysis in advance in order to result in displacements less than the allowable limits. Because analytical solution includes lots of assumptions, the pre-adjusting displacement should be reasonably controlled with considerations for the uncertainty due to these assumptions.

Trajectory Control of Excavator with Experimental Estimation of Cylinder Output Force (실린더 출력 힘의 실험적 추정을 통한 굴삭기 궤적제어)

  • Oh, Kyeong-Won;Kim, Dong-Nam;Kim, Nam-Hoon;Hong, Dae-Hie;Kim, Yun-Ki;Hong, Suk-Hie
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.1
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    • pp.48-55
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    • 2011
  • Hydraulic excavator is one of the most widely used heavy machines in construction sites including dismantling. In the dismantling sites, the excavators equipped with crusher or breaker carry out dangerous operations, so drivers are always exposed to unexpected danger. For safety operation, remote control of the hydraulic excavator has been studied using proportional control valve, which requires an appropriate motion control of its bucket tip. In this case, kinematics and dynamics analysis have to be preceded through modeling of excavator. However, it is difficult to acquire reasonable results from the analysis due to insufficient information of physical parameters such as mass of each links and locations of mass centers, etc. This study deals with the trajectory control of bucket tip, which is based on experimental estimation of cylinder output force. The estimated forces are fed into the control of each cylinder in order to compensate gravitational and frictional effects in the cylinders. The control was applied to horizontal trajectories that are for flattening work.

Manipulator Equipped with Counterbalance Mechanism Based on Gear Unit (기어유닛 기반 중력보상장치를 갖는 머니퓰레이터)

  • Kang, In Ho;Kim, Hwi Su;Song, Jae-Bok;Lee, Hyun Soo;Chang, In Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.289-294
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    • 2014
  • Industrial manipulators are usually heavy given the payloads they carry. Therefore, they require high-capacity servomotors and speed reducers, which leads to high costs. However, if manipulator weight could be compensated for using a counterbalance mechanism, the motors' and speed reducers' capacities could be minimized substantially. However, it is usually difficult to assure durability and reliability with the conventional wire-based counterbalance mechanism. Therefore, a more robust gear- and roller-based counterbalance mechanism is proposed in this study. A manipulator was developed using this mechanism; this manipulator maintains its performance even when using motors and reducers of lower capacities. The results of various simulations and experiments verified that the proposed mechanism provides the torque required to compensate for gravitational torque in any configuration and minimizes the torque required for supporting a large payload.

Development of In-wheel Actuator for Active Walking Aids Equipped with Torque Sensor for User Intention Recognition (토크센서 기반 사용자의도 파악이 가능한 보행보조기용 인휠 구동기 개발)

  • Lim, Seung-Hwan;Kim, Tae-Keun;Kim, Dong Yeop;Hwang, Jung-Hoon;Kim, Bong-Seok;Park, Chang Woo;Lee, Jae-Min;Hong, Daehie
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.12
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    • pp.1141-1146
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    • 2014
  • As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.

Exoskeleton Based on Counterbalance Mechanism for Arm Strength Assistance (중력보상장치 기반의 근력보조 외골격 장치)

  • Lee, Won Bum;Song, Jae-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.6
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    • pp.469-475
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    • 2017
  • Workers in industrial fields are highly exposed to accidents or injuries caused by long working hours. An exoskeleton that is able to support the arm muscles of the worker and thereby reduce the probability of an accident and enhance working efficiency could be a solution to this problem. However, existing exoskeletons demand the use of high-priced sensors and motors, which makes them difficult to use in industrial fields. To solve this problem, we developed an arm assisting exoskeleton that consists only of mechanical components without any electronic sensors or motors. The exoskeleton follows the movement of the human arm by shoulder joint and ankle joint. In addition, counterbalance mechanisms are installed on the exoskeleton to support arm strength. The experimental validation of the exoskeleton was conducted using an EMG sensor, confirming the performance of the exoskeleton.

Using DGPS as An Acceleration Sensor for Airborne Gravimetry

  • Zhang, Kaidong;Shen, Lincheng;Hu, Xiaoping;Wu, Meiping
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.327-332
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    • 2006
  • In airborne gravimetry, there are two data streams. One is the specific force measured by an air/sea gravimeter or accelerometers, the other is kinematic acceleration measured by DGPS. And the difference of them provides the gravity disturbance information. To satisfy the requirement of most applications, an accuracy of 1mGal $(1mCal=10^{-5}m/s^{2})$ with a spatial resolution of 1km is the aim of current airborne gravimetry. There are two different methods to derive the kinematic acceleration. The generally used method is to differentiate the position twice, and the position can be calculated by commercial DGPS software. The main defect of this method is that integer ambiguities need to be fixed to get the precise position solution, but it's not a trivial thing for long base line. And to fix integer ambiguities, the noisier iono-free measurement is used. When differentiation is applied, noise is amplified and will influence the accuracy of acceleration. The other method is to get carrier phase acceleration by differentiate the carrier phase first, and then using the acceleration of GPS satellite to derive the vehicle acceleration. The main advantages include that fixing integer ambiguities is not needed anymore, position can be relaxed to about 10 meters, and smoother acceleration can be got since iono-free measurement is not needed. In some literatures, it's considered that the dynamic performance of the second method is inferior to that of the first. Through analysis, it is found that the performance degradation in dynamic environment results from the simplification of the GPS carrier phase observable model. And an iterative algorithm is presented to compensate the model error. Using a dynamic GPS data from an aeromagnetic survey, the importance of this compensation is showed at last.

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Effect of robot arm reach training on upper extremity functional movement in chronic stroke survivors: a preliminary study

  • Cho, Ki Hun;Song, Won-Kyung
    • Physical Therapy Rehabilitation Science
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    • v.8 no.2
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    • pp.93-98
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    • 2019
  • Objective: The purpose of this study was to investigate the effect of robot arm reach training on upper extremity functional movement in chronic stroke survivors. Design: One group pretest-posttest design. Methods: Thirteen chronic stroke survivors participated in this study. Robot arm reach training was performed with a Whole Arm Manipulator (WAM) and a 120-inch projective display to provide visual and auditory feedback. During the robotic arm reach training, WAM provided gravity compensation and assist-as-needed (AAN) force according to the robot control mode. When a participant could not move the arm toward the target for more than 2 seconds, WAM provided AAN force to reach the desired targets. All patients participated in the training for 40 minutes per day, 3 times a week, for 4 weeks. Main outcome measures were the Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT) and Box and Block Test (BBT) to assess upper extremity functional movement. Results: After 4 weeks, significant improvement was observed in upper extremity functional movement (FMA: 42.15 to 46.23, BBT: 12.23 to 14.00, p<0.05). In the subscore analysis of the FMA upper extremity motor function domains, significant improvement was observed in upper extremity and coordination/speed units (p<0.05). However, there were no significant differences in the ARAT. Conclusions: This study showed the positive effects of robot arm reach training on upper extremity functional movement in chronic stroke survivors. In particular, we confirmed that robot arm reach training could have a positive influence by leading to improvement of motor recovery of the proximal upper extremity.