• Title/Summary/Keyword: measurement tool

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A Study on the Measurement Method and Uncertainty Factors for Precision Inspection to Feed Unit of High Precision Machine Tool (고정밀 공작기계 이송장치의 정밀도 측정방법 및 불확도 요인에 관한 연구)

  • Kim, Sang-Hwa;Kim, Byung-Ha;Choi, Woo-Gak
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.4
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    • pp.55-61
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    • 2012
  • Very important content in performance evaluation of machine tool is positioning accuracy and repeatability precision measurements of feed mechanism. A study analyses the measurement method and uncertainty factors by ISO-based test method. Reliable results can't be derived without the notion of measurement uncertainty. The reason is that the measured value includes a lot of uncertain factors. Finding the factor that affects the measurement of parameter is important for estimation of measurement precision. In this paper, the evaluation of uncertainty analysis about positioning accuracy and repeatability precision measurements of high precision feed mechanism is presented to evaluate the important factors of uncertainty.

Diagnostic Framework for Performance Measurement Practices of Public Broadcasting (공영방송 성과측정관행의 진단 틀)

  • Min, Jae-H.
    • Korean Management Science Review
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    • v.26 no.1
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    • pp.137-159
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    • 2009
  • An organizational performance measurement practice is a function of performance measurement system and performance management system they are currently employing, and its quality is determined by evaluating the followings in a comprehensive manner: first, if they are measuring right things; second, if they are measuring in a right way; third, if they are actively facilitating a process of data collection, structuring, analysis, interpretation, and dissemination; and fourth, if they are using performance measurement results for the primary purposes of performance measurement. This study proposes a diagnostic framework for evaluating the performance measurement practices of public broadcasting which include the qualities of performance measurement and performance management, and develop a structured questionnaire for that purpose. The framework proposed in this study does not serve only as a useful tool for public broadcasting to revise their respective performance measures and performance measurement systems, but it also make their respective performance measurement practices a strategic management tool as well as an operational management one.

Detection of Tool Wear by Using the Ultrasonic in-Process Sensor (초음파 인프로세스 센서를 이용한 공구마멸 검출)

  • Kang, H. S.;Chung, E. S.;Hwang, J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.852-856
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    • 1997
  • This paper describes a ultrasonic method for direct measurement of tool wear in turning operations. An integrated single ultrasonic transducer operating at a frequency of 10MHz is placed in contact with the insert tip. The change in amount of the reflected energy form the nose and flanks of the tool can be related to the level of tool wear and thr mechanical integrity of the tool. As a results, a correlation exists between the untrasonic measurement and tool wear and that it is tool dependent.

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Research on the Effect of Cutter Wear on the Torsional Vibration of Spindle in Milling (밀링가공에서 공구마모와 스핀들의 비틀림 진동과의 상관관계에 관한 연구)

  • Kim, Seog-Gwan
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.9
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    • pp.62-67
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    • 1999
  • In milling, cutting tool ins directly attached to spindle and this tells that spindle can provide very useful information on the cutting tool condition such as wear or breakage. Since spindle is rotating at a high speed, measuring spindle velocity using a noncontacting measurement system gives the best information which can be obtained. Due to the force applied to spindle through cutting tool, velocity of spindle changes. And any change in cutting tool condition affects cutting force and consequently spindle vibration. With the intent of continuously monitoring cutting tool condition in intermittent machining operations in a benign manner, a noncontacting velocity measurement system using a laser Doppler velocimeter was assembled to measure spindle torsional vibration. Spindle vibration was measured and analysis of it in the frequency domain yielded a measure which corresponded to amount of cutting tool wear in milling.

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An Analysis of Research on Fatigue (피로와 관련된 논문 분석)

  • 변영순;박미숙
    • Journal of Korean Academy of Nursing
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    • v.26 no.4
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    • pp.868-877
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    • 1996
  • This study was done to analyze research trends and to suggest future perspectives for nursing research on fatigue. The author reviewed 31 Korean and foreign research papers which have been published in the literature since 1970. An analysis of the study focused on the type of research subjects, type of study design. measurement instrument, and its correlated parameters. The results of the study are summarized as follows : First, within all of the studies analayzed, 14 studies were publised in Korea and 17 were published abroad. The number of studies done abroad have been increasing rapidly since 1991. Second, an analysis of the research design of the studies showed, eight studies each, Korean and foreign used survey design. Two Korean studies and seven foreign studies used a correlational design. Four comparative studies were done in Korea, but only two experimetal studies were performed abroad. Therefore, it was found that the trend of the study design used is survey design and there are more correlational studies done abroad than in Korea. Third, the type of the study subjects ; 11 Korean and three foreign studies dealt with healthy people. In addition, three Korean and 14 foreign studies investigated patients with various illnesses. It was found that patients with various illnesses were studied more frequently in foreign studies than in Korean studies. Fourth, the measurement tool used in the Korean studies ; 13 studies used a testible tool to assess patients' subjective symtoms or complaints of fatigue. The most commonly used tool used in 10 studies, was the Fatigue Self-Perception Scale, which was designed by the Labor and Health Institute of Japan. The Visual Analogue Scale was used in two studies, and Piper Fatigue Scale, addtional with physiologic parameters, was used in one study. In the foreign studies, subjective measurement tools were used in 16 studies. A combination of a subjective measurement tool with objective parameters was used in ten studies. For the subjective measurement tool used in the foreign studies, a specific measurement tool developed by the researcher which was used in seven studies. Either Rhoten Fatigue Scale or the Visual Analog Scale were used in three studies. Additionally, in order to identify the relationship between fatigue and psychological factors, The Profile of Mood State was used in three studies. Beck Depression Inventory was used in two studies. The Self Rated Depression Scale, developed by Zung, was used in one study and other measurement tools were used to measure various psychological parameters. Rhoten fatigue Checklist was also used to observe behavior patterns. Lastly, nine studies identified correlations between fatigue and other parameters. A significant correlation was found between fatigue and psychological factors such as depression, and pain. As a result of the above findings, it can be said that research trends on fatigue are increasing internationally. The selected study designs are survey studies both in Korea and abroad. There are more correlational studies abroad than in Korea. In addition, subjective measurement tools and objective parameters are used variously and combined with each other. had, there is a significant correlation between fatigue and psychological factors such as depression, and pain. More survey and correlational studies need to be done to identify the relationship of fatigue in patients with various condition or diagnoses and to suggest a scientific basis for nursing interventions with fatigue. Also, a tool to assess patient's subjective, objective, and behavioral aspects on fatigue needs to be developed.

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A Study on the Measurement of Motion Accuracy for Feed Drive System of Multi-task Machine Tool (복합공작기계의 이송계 운동정밀도 측정의 연구)

  • Ko, Hai-Ju;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.112-118
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    • 2007
  • Recently, the machine tools called multi-task machines, which mounted rotary axes on the table or spindle are used increasingly. Accordingly, multi-task machine tool takes a growing interest on the motion accuracy of feed drive system. In this study, measurement and diagnosis of motion errors ware attempted from circular pattern obtained by using DBB (Double ball bar) device. Those were obtained at both clockwise and counter clockwise motions in mutually perpendicularly intersecting three planes. The reliability of error measurement system for multi-task machine tool was verified by the direct test cutting.

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A Study on the Measurement of Motion Accuracy for Feed Drive System of Multi-task Machine Tool (복합공작기계의 이송계 운동정밀도 측정의 연구)

  • Ko, Hai-Ju;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.31-37
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    • 2007
  • Recently, the machine tools called multi-task machines, which mounted rotary axes on the table or spindle are used increasingly. Accordingly, multi-task machine tool takes a growing interest on the motion accuracy of feed drive system. In this study, measurement and diagnosis of motion errors ware attempted from circular pattern obtained by using DBB (Double ball bar) device. Those were obtained at both clockwise and counter clockwise motions in mutually perpendicularly intersecting three planes. The reliability of error measurement system for multi-task machine tool was verified by the direct test cutting.

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The Development of An Error Measurement System of 5-Axis Mill & Turn Machine Tool by Double Ball Bar Test (DBB를 이용한 5축 복합가공기의 오차 측정 시스템 개발에 관한 연구)

  • Kim T.H.;Jung Y.G.;Ko H.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.243-244
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    • 2006
  • In this paper, the development of an error measurement system of 5-axis mill & turn machine tool presented by double ball bar test, which has been widely used to measure the overall accuracy of machining center. and the reliability of an error measurement system of 5-axis mill & turn machine tool was secured by the direct cutting test.

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Measurement and analysis of CNC machine tool errors using ball link bar system (Ball link bar를 이용한 CNC 공작 기계의 정밀도 계측과 해석에 관한 연구)

  • Kwon, Hyuk-Dong
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.3
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    • pp.289-296
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    • 1997
  • In this paper, a method has been proposed for error measurement/diagnosis of CNC machine tools using the ball link bar on three dimensional space. For the circular motion error measurement, deviation between the desired and actual test path has been measured and analysed using a new type of ball link which incorporates ideal three point contact between reference balls and sockets. Computer program for the error evaluation has been developed and implemented under PC environment. Using the developed program, the circular test data on a CNC machine tool have been analysed, and thus, machine tool errors were effectively evaluated.

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Development of an evaluation tool model for the effective measurement of cyber motion sickness in immersive virtual reality

  • Kim Seung Uk
    • International Journal of Advanced Culture Technology
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    • v.12 no.2
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    • pp.345-352
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    • 2024
  • We are designed to solve cyber motion sickness, an important task that must be addressed for the growth of the virtual reality content industry. Not only the industry but also academia are paying a lot of attention. However, despite long interest and research on the phenomenon of cyber motion sickness, a solution has not been drawn. This is deeply related to the lack of tools that can effectively measure cyber motion sickness. Therefore, in this paper, prior studies on cyber motion sickness were analyzed to develop a tool that can effectively measure cyber motion sickness when users experience immersive virtual reality. The measurement method of cyber motion sickness used in previous studies, each characteristic and limitation, and common factors related to cyber motion sickness were analyzed. Each of the related factors was derived as sub-factors. Based on the analyzed contents, an effective cyber motion sickness measurement evaluation tool model in immersive virtual reality was presented. It is expected that the evaluation tool model can be used for the study of cyber motion sickness.