• Title/Summary/Keyword: Geared System

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Design and Optimization of Active Transfemoral Prosthesis System (능동형 대퇴의지 시스템의 설계 및 최적화 연구)

  • Chung, J.H.;Lee, K.H.;Lee, C.H.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.8 no.4
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    • pp.283-289
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    • 2014
  • This paper presents a design and optimization of the fully-active transfemoral prosthesis leg system. As it has one degree of freedom in knee joint, this prosthesis leg can imitate the human's gait. The weight of system, which makes the users more comfortable due to less tiredness, and the knee joint torque to rise stability of the system are major factors of prosthesis leg system. Thus the mechanism of prosthesis changes from 3-linkage type to geared type. The sensorized foot is also designed to effectively determine human's gait by measuring deformation of the foot during gait. Topology optimization is carried out for the sensorized foot to remove its unnecessary weight. The safety of optimized foot is verified by carrying out finite element analysis.

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Review on the Trends of Social Sciences Research in the International Agricultural Research Institute - Focused on the International! Rice Research Institute (IRRI) - (국제농업연구기관의 사회과학연구 동향 고찰 -국제미작연구소를 중심으로-)

  • 윤순덕
    • The Korean Journal of Community Living Science
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    • v.15 no.3
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    • pp.45-56
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    • 2004
  • The purpose of this paper is to review research evolution and achievements, major activities, research manpower, and difficulties for social scientists, using IRRI's internal web site and Social Sciences Division's research literatures. The major findings are as follows: 1) Social research started with the establishment of Agricultural Economics Division (AED) in 1966, and it was developed into the Social Sciences Division (SSD) in 1990; 2) Their research has been geared towards developing technological and policy interventions that improve food security and raise the well-being of rice farmers through sustainable increase in the productivity of a rice-based production system; 3) Major activities of social sciences research for about four decades can be classified into the identification of technology needs, technology impact assessment, policy analysis, research prioritization, and capacity building for social science research in NARS (National Agricultural Research Systems). They have become increasingly important in alleviating the poverty of the rice growing and consuming population; 4) Social researchers at IRRI include economists, anthropologists, gender specialists, geographic information specialists, and rural sociologists; 5) Finally, this paper discusses the difficulties faced by social researchers.

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Current Activities of Navigation & Communication Equipments Industry and R&D (항해통신장비산업과 연구개발현황)

  • Mun, Seong-Mi;Son, Joo-Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.4
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    • pp.512-518
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    • 2011
  • The marine equipment industry in Korea has been growing along with shipbuilding industry since early 1980s. Major shipbuilding might be predicted to shift to China in the near future. Moreover, new paradigm of e-navigation is about to get geared in the real world, which was specifically noted by IMO (International Maritime Organization). In order to catch up with rapid changes in the environments, the industry sector should move fast, the public sector should setup proper measures, and the academic sector should spur the research and development of new technologies. In this paper, international marin equipment markets and standardization trends are presented along with several representative R&D activities.

The Study of Reclaimer of Antiseptic Solution for Winter-sowing Prevention of a Vehicle Disinfector at Livestock Farm (축산농가 차량소독기의 동파방지를 위한 약액 회수장치에 관한 연구)

  • Kim, W.;Lee, S.K.
    • Journal of Animal Environmental Science
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    • v.13 no.1
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    • pp.29-34
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    • 2007
  • This study was conducted to develop a reclaimer of the vehicle disinfector to be used at livestock fm. The reclaimer was mainly consisted of ball-valves, geared motors and one-chip processor, and the purpose of the system was to prevent liquid freezing as well as decrease environmental pollution of antiseptic solution. The properly spraying pressure of the vehicle disinfector was found over 1.96 MPa at 1m of the spraying range. While certain amount of the antiseptic solution remained in the injection-pipes, the spray starting time was found not making any significant effect on the remained amount of the antiseptic solution. The amounts of the antiseptic solution remained in the injection-pipes were 50 ml and 270 ml in average, respectively with and without the use of the reclaimer. The reclaimer was the most effective when the connection of the injection-pipe and sprayer line was located below the side-injection-pipe and then connected to the injection-pipe located at the bottom of vehicles.

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Performance of Mature and Matriculation Entry Students Studying Towards the National Diploma in Building at the University of Johannesburg, South Africa

  • Wellington Didibhuku Thwala
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.647-652
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    • 2011
  • Developments in the teaching of the National Diploma in Building students should be geared towards meeting the needs of the construction industry in South Africa. These needs are usually in the form of skills and knowledge required to resolve thorny issues encountered in practice. The lack of capacity in the construction industry needs to be addressed from the basis of ensuring that the education system caters for both mature entry and matriculation entry students. The paper looks at a comparison in performance between mature entry and matriculation (just finish High School) entry students focusing on the National Diploma in Building students at the University of Johannesburg. The paper will make a comparison between those students who work first before enrolling for their first year National Diploma in Building and those who are directly from high school. Cooperative education involves training and systematically developing students through the acquisition of the requisite skills, attitudes, values and knowledge required to adequately perform in their chosen careers. The paper describes the problems and experiences that have been encountered by both mature and matriculation entry students in their three years of study which affects their performance. The paper will then look at the value of prior experience in enabling students to finish their National Diploma in Building within a three year period. The paper closes with some recommendations for the future.

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Performance Analysis of Oil-lubricated Thrust Collars in Integrally Geared Compressors (증속 기어 압축기용 스러스트 칼라의 윤활 성능 해석)

  • Lee, Donghyun;Kim, Byungok;Sun, Kyungho
    • Tribology and Lubricants
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    • v.34 no.5
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    • pp.169-174
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    • 2018
  • A multi-stage compressor (MSC) is comprised of several impellers installed in the pinion gear shaft driven by a main bull gear. In the pinion shaft, a thrust collar (TC) is installed to support the thrust load. The TC makes the lubrication system simpler in the MSC; therefore, it is widely used in similar kinds of machinery. Typically, TCs are installed on both sides of the bull gear and pressure is developed in the lubricated area by creating a taper angle on the TC and bull gear surface. In the current study, we developed a numerical analysis model to evaluate the performance of the TC considering its design parameters. We sloved the Reynolds equation using the finite element method and applied the half Sommerfeld condition to consider cavitation. Based on the pressure calculated in the lubricated area, we calculated the power loss and minimum film thickness. In addition, we calculated stiffness and damping using perturbation method. We performed parametric studies using the developed model. The results of the analysis show that the maximum pressure presents in the center area of the TC and it increases with the taper angle. The area over which pressure is developed decreases with the taper angle. The results also show that there is an optimum taper angle providing minimum power loss and maximum film thickness. Additionally, the stiffness and damping decrease with the taper angle. As the applied load increases, the power loss increases and the minimum film thickness decreases. However, the stiffness and damping increase with the applied load.

Learning Systems of Shin, Han-Seung's Taekkyeon (신한승택견의 학습체계)

  • Park, Yeong-Kil;An, Jeong-Deok
    • The Journal of the Korea Contents Association
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    • v.8 no.8
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    • pp.235-243
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    • 2008
  • This research show how Shin Han-Seong make up Taekkyeon to register to intangible cultural assets, and found next conclusion and meaning. First, skill organization of Song Duk-Ki Taekkeon that is only one modem Taekkeon's initiator have been transmitted for a piece of skills of playing figure which don't have regular system. But Taekkyeon which have regular system have been developed by Shin Han-Seong, finally Taekkyeon is approved to intangible cultural assets. Second, Shin Han-Seong modernized Taekkyeon by borrowing training system of Judo, Fencing, Hapgido, Taekwondo, Karate. But people criticize that Song Duk-Ki Taekkeon is not initiate with original thing. Third, Shin Han-Seong made the grade classification and practical technique screening, Bon-Dae Buigi Twelve part like Pomse of Taekwondo (there is no for traditional Taekkyeon). And he contributed to popularization and modernized learning system by pursuiting sportization. Through this research geared up Taekkyeon's original shape and generational outline about skill transition or composition. And it gave important data for understand about Taekkyeon controversy which scattered.

Development of 3 D.O.F parallel robot's simulator for education

  • Yoo, Jae-Myung;Kim, John-Hyeong;Park, Dong-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2290-2295
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    • 2005
  • In this paper, it is developed simulator system of 3 D.O.F parallel robot for educate of expertness. This simulator system is composed of three parts ? 3 D.O.F parallel robot, controller (hardware) and software. First, basic structure of the robot is 3 active rotary actuator that small geared step motor with fixed base. An input-link is connected to this actuator, and this input-link can connect two ball joints. Thus, two couplers can be connected to the input-link as a pair. An end-plate, which is jointed by a ball joint, can be connected to the opposite side of the coupler. A sub-link is produced and installed to the internal spring, and then this sub-link is connected to the upper and bottom side of the coupler in order to prevent a certain bending or deformation of the two couplers. The robot has the maximum diameter of 230 mm, 10 kg of weight (include the table), and maximum height of 300 mm. Hardware for control of the robot is composed of computer, micro controller, pulse generator, and motor driver. The PC used in the controller sends commands to the controller, and transform signals input by the user to the coordinate value of the robot by substituting it into equations of kinematics and inverse kinematics. A controller transfer the coordinate value calculated in the PC to a pulse generator by transforming it into signals. A pulse generator analyzes commands, which include the information received from the micro controller. A motor driver transfer the pulse received from the pulse generator to a step motor, and protects against the over-load of the motor Finally, software is a learning purposed control program, which presents the principle of a robot operation and actual implementation. The benefit of this program is that easy for a novice to use. Developed robot simulator system can be practically applied to understand the principle of parallel mechanism, motors, sensor, and various other parts.

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Optimization of Fuzzy Inference Systems Based on Data Information Granulation (데이터 정보입자 기반 퍼지 추론 시스템의 최적화)

  • 오성권;박건준;이동윤
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.6
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    • pp.415-424
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    • 2004
  • In this paper, we introduce and investigate a new category of rule-based fuzzy inference system based on Information Granulation(IG). The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient form of “If..., then...” statements, and exploits the theory of system optimization and fuzzy implication rules. The form of the fuzzy rules comes with three types of fuzzy inferences: a simplified one that involves conclusions that are fixed numeric values, a linear one where the conclusion part is viewed as a linear function of inputs, and a regression polynomial one as the extended type of the linear one. By the nature of the rule-based fuzzy systems, these fuzzy models are geared toward capturing relationships between information granules. The form of the information granules themselves becomes an important design features of the fuzzy model. Information granulation with the aid of HCM(Hard C-Means) clustering algorithm hell)s determine the initial parameters of rule-based fuzzy model such as the initial apexes of the membership functions and the initial values of polynomial function being used in the Premise and consequence Part of the fuzzy rules. And then the initial Parameters are tuned (adjusted) effectively with the aid of the improved complex method(ICM) and the standard least square method(LSM). In the sequel, the ICM and LSM lead to fine-tuning of the parameters of premise membership functions and consequent polynomial functions in the rules of fuzzy model. An aggregate objective function with a weighting factor is proposed in order to achieve a balance between performance of the fuzzy model. Numerical examples are included to evaluate the performance of the proposed model. They are also contrasted with the performance of the fuzzy models existing in the literature.

A study on implementation of adult learner-targed college based on case study of foreign universities: Focused on cases of US and UK (해외 사례분석을 통한 성인전담 단과대학 운영방안: 미국과 영국 대학을 중심으로)

  • CHO, DAEYEON;Kim, Jeong-Ju
    • (The)Korea Educational Review
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    • v.23 no.1
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    • pp.379-404
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    • 2017
  • The purpose of this study is to seek practical implementation of adult learner-targeted college. For this, it first of all pointed out expanding opportunities of adult learners to learn and limitation of current lifelong education system at higher education level as well as lifelong learning centered university project. Then it selected and examined 3 university cases abroad, such as Harvard university, the university of Chicago in US and Warwick university in UK in terms of their curriculum and operating method for adult learners. In addition to the literature and case studies, this study did interviews on 5 professors with major of lifelong education and 5 managerial experts of university to suggest practical operating approach of adult learner-targeted college, which is as following. University's philosophy should be geared to meet public responsibility, specialization and persistency of the system and proper measurement be followed such as various range of admission track, prior education courses, recognition of prior learning experience, major, teaching method, curriculum and extra adult learner tailored service including financial support. Based on the study result, practical implications were suggested.