• Title, Summary, Keyword: Statics Relation

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The Forward/Inverse Force Transmission Analyses of the Stewart Platform (스튜어트 플랫폼의 순방향/역방향 힘 전달 해석)

  • Kim, Han-Sung;Choi, Yong-Je
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.5
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    • pp.200-208
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    • 1999
  • The statics relation of the Stewart platform has been investigated from the viewpoint of the forward and inverse force transmission analyses. Two eigenvalue problems corresponding to the forward and inverse force transmission analyses have been formulated. The forward force transmission analysis is to determine the ranges of the magnitudes of the force and moment generated at the end-effector for the given magnitude of linear actuator forces. In reverse order, the inverse force transmission analysis is to find the range of the magnitude of actuator forces for the given ranges of the magnitudes of the force and moment at the end-effector. The inverse force transmission analysis is important since it can provide a designer with a valuable information about how to choose the linear actuators. It has been proved that two eigenvalue problems have a reciprocal relation, which implies that solving either of the eigenvalue problems may complete the forward/inverse force transmission analysis. A numerical example has been also presented.

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Geometrical Velocity and Force Analyses on Planar Serial Mechanisms (평면 직렬 메커니즘의 기하학적 속도 및 힘 해석)

  • Lee, Chan;Lee, Jeh Won;Seo, TaeWon
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.7
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    • pp.648-653
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    • 2015
  • The kinematics with the instantaneous motion and statics of a manipulator has generally been proven algebraically. The algebraic solutions give very simple and straightforward results but the solutions do not have any meaning in physics or geometry. Therefore it is not easy to extend the algebraic results to design or control a robotic manipulator efficiently. Recently, geometrical approach to define the instantaneous motion or static relation of a manipulator is popularly researched and the results have very strong advantages to have a physical insight in the solution. In this paper, the instantaneous motion and static relation of a planar manipulator are described by geometrical approach, specifically by an axis screw and a line screw. The mass center of a triangle with weight and a perpendicular distance between the two screws are useful geometric measures for geometric analysis. This study provides a geometric interpretation of the kinematics and statics of a planar manipulator, and the method can be applied to design or control procedure from the geometric information in the equations.

A Study on Factors Affecting Public Health Center Workforce for Health Behavior based on Pender's Health Promotion Model (서울지역 일부 보건소 공무원의 지각된 건강상태와 건강행동과의 관련성 -Pender의 건강증진모델을 이용하여-)

  • Lee, Eun-Jeoung;Lee, Myung-Sun
    • The Journal of Korean Society for School & Community Health Education
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    • v.15 no.1
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    • pp.121-140
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    • 2014
  • Objectives: Recently, the rate of death by chronic disease, is increasing steadily. To prevent this, the public health center will have taken a leading role in the local community medical business through an establish to the national health promotion act and an amendment to the law of public health center in Korea. Results: Accordingly this research, using the Pender's health promotion model which is related with subject health behavior who government employees serve at the public health center have taken important position in the local community health promotion, have comprehended the actual condition of health behavior. For increasing the health behavior practice of subject to comprehend the factor which have effect on health behavior practice, which can be a correct role model in the local community health promotion. A survey was performed on 406 government employees who serve at five public health centers in Seoul. The period of survey was from 25th October, 2010 to 15th November, 2010. The results of this study were summarized as below. 1. Work-related stress, perceptible beneficial obstacle, and self-efficacy were composed by 5 points measure. The results show those work-related stress were $3.06{\pm}0.469$, 74perceptible beneficial obstacle were $3.74{\pm}0.471$, and self-efficacy were $3.49{\pm}0.469$. 2. As for the health behavior by general characteristic, the results have specific differences on age, education level, state of marriage, rank of the position, field of the occupation and employment forms in statics analysis. 3. As for the past health behavior by health behavior characteristic, work-related stress have specific differences on the past frequency of drinking (p<.05) in statics analysis, perceptible beneficial obstacle have specific differences on the past frequency of having breakfast(p<.05), having snacks(p<.05) and doing exercise(p<.05) in statics analysis. Self-efficacy have specific difference on the past frequency drinking(p<.01) in statics analysis. 4. According to the correlation between the factors related with health behavior and health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). Work-related stress and self-efficacy don't have specific relation in health behavior practice. 5. The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations. The ability of explanation occupied 54.8% what explained of the health behavior practice by general characteristic, perceptible health condition, employment forms and perceptible beneficial obstacle. Conclusions: According to the correlation between the factors related with health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations.

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Development of a 6-axis Robotic Base Platform with Force/Moment Sensing (힘/모멘트 측정기능을 갖는 6축 로봇 베이스 플랫폼 개발)

  • Jung, Sung Hun;Kim, Han Sung
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.3
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    • pp.315-324
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    • 2019
  • This paper present a novel 6-axis robotic base platform with force/moment sensing. The robotic base platform is made up of six loadcells connecting the moving plate to the fixed plate by spherical joints at the both ends of loadcells. The statics relation is derived, the robotic base platform prototype and the loadcell measurement system are developed. The force/moment calibrations in joint and Cartesian spaces are performed. The algorithm to detect external force applied at a working robot is derived, and using a 6-DOF robot mounted on the robotic base platform, force/moment measurement experiments have been performed.

Stiffness Analysis of a Low-DOF Parallel Manipulator using the Theory of Reciprocal Screws (역나선 이론을 이용한 저자유도 평행구조 기구의 강성해석)

  • Kim, Han-Sung
    • Proceedings of the KSME Conference
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    • pp.573-578
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    • 2004
  • This paper presents a methodology for the stiffness analysis of a low-DOF parallel manipulator. A low-DOF parallel manipulator is a spatial parallel manipulator which has less than six degrees of freedom. The reciprocal screws of actuations and constraints in each leg can be determined by making use of the theory of reciprocal screws, which provide information about reaction forces due to actuations and constraints. When pure force is applied to a leg, the leg stiffness is modeled as a linear spring along the line. For pure couple, it is modeled as a rotational spring about the axis. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to actuations and 6-F springs related to constraints connected from the moving platform to the base in parallel. The $6{\times}6$ Cartesian stiffness matrix is obtained, which is the sum of the Cartesian stiffness matrices of actuations and constraints. Finally, a 3-UPU parallel manipulator is used as an example to demonstrate the methodology.

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Development of Fuzzy Membership Function for Emotional Satisfaction Quantification (감성 만족도의 정량화를 위한 퍼지 소속 함수 개발)

  • Park, Jun-Seok;Myeong, No-Hae
    • Journal of the Ergonomics Society of Korea
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    • v.23 no.2
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    • pp.37-54
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    • 2004
  • Fuzzy theory provides an intelligence treatment model for judgement about information when it needs a solution or a decision making about vague problems. Therefore, fuzzy theory is used for appropriate evaluation and decision on obscure information as human's emotion in human factors, In previous study, fuzzy membership function is defined for judgement infOlmation as human's emotion then ultimate results are deducted through fuzzy inference model. This method uses general CWTent through literature review or max, min and average as representative statics value about considering variables. But, this method makes away with nonlinear's or inegular's factors of human sensibility. Accordingly, application of this method leads to considerable loss of information in the ultimate evaluation. For that reason, this method has a limitation in objective evaluation of human factors. So, this study focuses on development of fuzzy membership function, which evaluates human's emotion or feeling accurately and objectively. We used the regression analysis and reasoned a fuzzy membership function about the relation of the variables. Then we verified the adequacy with the reliability through the experiment after this.

Stiffness Analysis of a Low-DOE Parallel Manipulator using the Theory of Reciprocal Screws (역나선 이론을 이용한 저자유도 병렬형 기구의 강성해석)

  • Kim Han Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.5
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    • pp.680-688
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    • 2005
  • This paper presents a methodology for the stiffness analysis of a low-DOF parallel manipulator. A low-DOF parallel manipulator is a spatial parallel manipulator which has less than six degrees of freedom. The reciprocal screws of actuations and constraints in each leg can be determined by making use of the theory of reciprocal screws, which provide information about reaction forces due to actuations and constraints. When pure farce is applied to a leg, the leg stiffness is modeled as a linear spring along the line. For pure couple, it is modeled as a rotational spring about the axis. It is shown that the stiffness model of an it_DOF parallel nipulator consists of F springs related to actuations and 6-F springs related to constraints connected from the moving platform to the base in parallel. The 6x f Cartesian stiffness matrix is derived, which is the sum of the Cartesian stiffness matrices of actuations and constraints. Finally, the 3-UPU, 3-PRRR, and Tricept parallel manipulators are used as examples to demonstrate the methodology.

A study of Movement on Modern Fashion (현대 의상에 나타난 움직임의 표현성)

  • 이상례;임영자
    • Journal of the Korean Society of Costume
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    • v.20
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    • pp.125-135
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    • 1993
  • The purposes of this research are firstly to define the characteristics of movement on the costume, secondly to demonstrate that fine art, expecially in relation to kinetic art, has become a good motif in modern costume de-sign, and thirdly to examin the characteristics of movement as shown in modern costume de-sign. For this study, we selected and analyzed some costume designs among those introduced in fashion magazines, which are Collections, Fashion-Preview, Fashion Show, Collezioni, and L'Officiel that have been issued since 1988. As this research is carried out only through the analysis of pictures, it is not ac-companied by a study on material itself. The result of this study is that the ex-pression of movement on modern fashion can be shown in two ways, one is the inclusive and subordinate movement expressed on the cloth-ing according to the motion of body when they are worn, and the other is the movement caused by the very designs of clothing. And the latter can be also divided in two ways, the illusionistic movement and the actual move-ment. The expression of actual movement is made through the emphasis of direction, rhythm, and dimension of the costume. And the illusionistic movement is expressed by the de-sign to which the textile pattern or reflection of light is applied so that the movement is larger than the actual movement. A sense of direction expressed on the cos-tume by the actual movement creates a light rhythm and adds interest to the costume. This reflects a part of psychology of modern men who are not accustomed to the statics. In the rapidly changing society of information our modern men seek after movement even in the statics. It is also true in the clothing and they seem to get a psychological rest through the immediated visual change as shown in fashion design. The simple and cheerful rhythm expressed by the illusionistic movement on the costume is attempted in order to overcome the static tediousness caused by simple design. These elements of movement cause the en-largement of visible range and create another enlarged shape other than the real one, so that they come to remove the dullness and monot-ony in costume design and provoke interest in costume, as if kinetic art reveals the various aspects that transcend the closed area of fine art upon the motif of 'movement'. finally, as this paper deals with the ex-pression of movement as shown in the costume design which prevailed after 1988, it is desir-able hereafter to study more about the fashion since 1950 when kinetic art began in earnest, along with the comparative study on the ex-pression of movement in our Korean designer's and foreign designer's works.

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A Study on the Effect of Outsourced to Management Performance (아웃소싱이 기업성과에 미치는 영향)

  • Bae, Ha Jin;Kwak, Soon Jin;Kim, Kwang Soo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.5
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    • pp.83-94
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    • 2014
  • Before economical crisis in 1997, domestic company focused on increasing the size of outward experience which including organization. The result of increasing outward experience without substance was economical crisis, so after that time, many companies have been changing their focus from insourcing to strengthen the core competence to secure global market. This is becoming a cause of following that companies are reducing their outward experience. Especially, to process tasks more effectively and to cope with rapid change of business environment, such as incoming raw material from overseas/high raising of salary/rising property prices, many companies decided outsourcing method. At most of hypothesis, the result was that outsourcing can affect positively to the business. First, introducing of outsourcing during focusing on core competence can be positive effect for company performance such as business management /productivity /procurement /administration /product competitiveness /technology. Second, the result that analyzed based on a point of view of population statics after outsourcing was positive effect at the most of research. Third, result of effectiveness for every outsourcing type classified by 4M was also can be positive at the most of research. Fourth, the characteristic of population statics can be positive effect at the most of category when select outsourcing companies. Research result of outsourcing was various based on the goal of outsourcing. It is revealed by investigation of domestic/overseas treatise that there are opposite two opinions. In this research, there is no consistent result that the outsourcing can give effects on business performance, but most of hypothesis indicates that outsourcing can give positive effect on the business performance.In this research, based on the outsourcing intensity, mutual relation was analyzed. The assumption of the reason of outsourcing is economical and organizational. First, sampling numbers of research was too small so it is too difficult to get significant business performance result. (Sampling : 150, Replied : 106, Rate of Reply : 71%) Second, tried to compare significant differences of outsourcing methods which were divided based on 4M, but the there is gaps between the number of Cell and too difficult to make replier understand. Third, it is tried to find the degrees of effect that the point of view of popular statics can effect on business performances and selection of outsourced companies.

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Stiffness Analysis of a Low-DOF Parallel Manipulator including the Elastic Deformations of Both Joints and Links (ICCAS 2005)

  • Kim, Han-Sung;Shin, Chang-Rok;Kyung, Jin-Ho;Ha, Young-Ho;Yu, Han-Sik;Shim, Poong-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.631-637
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    • 2005
  • This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

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