• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.453-457
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• 2001

One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. In this study, the compensation device is manufactured in order to compensate thermal error of machine tools under the real-time. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.21-26
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• 2005

It is important to measure the rotational accuracy of NC lathe spindle as it affects to the qualities of all machines machined by the NC lathe using in industries. The bad rotational accuracy of NC lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of NC lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental appratus for measuring of rotational accuracy by using eddy current type gap sensors, converters, screw terminal, data acquisition board inserted in computer and software f3r data acquisition, DT VEE ver. 5.0 and then error data acquired in the rotational accuracy test of NC lathe spindle are analysed in plots and statistical treatments.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.294-299
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• 2005

A machining center is a complex dynamic system whose behavior influences the machining stability and machined surface quality. This paper focused on establishment of a measurement system and experimental study on static, dynamic, and modal analysis of a machining center. The dynamic stiffness result by the analysis showed the weak part of the machining center. The results provided structure modification data for getting better dynamic behaviors.

• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.103-109
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• 2021

The study aimed to analyze the current situation of the electronic portal of the Northern Border University, in terms of content and components, the extent of quality of use, service assurance and integrity, linguistic coverage of objective content, in addition to assessing the efficiency of the Blackboard e-learning platform and measuring the degree of safety of the portal, in addition to measuring the extent of satisfaction, through a sample that included 135 faculty members, as the researcher was keen to apply the case study methodology with the use of the questionnaire as the main tool for measurement, and the study found that there is an average trend among faculty members in the degree of content for the components of the portal and electronic security While it rose to good use, and very good at using the Blackboard platform.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.518-522
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• 2015

Green Construction is the construction activities that conserved energy, land, water and material to reduce the negative effect to the environment while assuring essential demand on quality and safety during project construction. This paper critically examine the contribution of awareness and understanding, green construction practices and green construction innovation with the green construction benefits. A measurement model based on the theoretical framework and exploratory factor analysis was developed and tested using structural equation modelling technique. This study employs a survey research methodology involving a total of 346 respondents among construction contractors, developers, clients and consultants in the construction industry. The findings indicate that the awareness and understanding, green construction practices and green construction innovation are significant predictors of the green construction benefits. From the practical perspective, the findings should alert the construction participants on the need of awareness and understanding, green construction practices and green construction innovation towards the green construction benefits. In addition, the findings can be used as diagnostic tool for continuous improvements in the Malaysian construction industry.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.190-206
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• 1996

In case measurements are made on units of production in time order, it is reasonable to expect that the measurement errors will sometimes be first order autocorrelated, and a technique to test such autocorrelation is required to give good control of the productive process. Tool-wear process provide an example for which regression model can sometimes be useful in modeling and controlling the process. For the control of such process, we present a simple method for testing first order autocorrelation in regression errors. The method is based on Bayesian test method via Bayes factor and derived by observing that in general, a Bayes factor can be written as the product of a quantity called the Savage-Dickey density ratio and a correction factor ; both terms are easily estimated from Gibbs sampling technique. Performance of the method is examined by means of Monte Carlo simulation. It is noted that the test not only achieves satisfactory power but eliminates the inconvenience occurred in using the well-known Durbin-Watson test.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.85-91
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• 2014

The rotation of a spindle unit must be accurate for high-quality machining and to improve the quality of the machine tools. Therefore, the proper measurement of the rotation accuracy and ensuring a proper analysis are very important. Separate processes are necessary because spindle errors and roundness errors associated with the test balls can both factor into the measured rotation error values. We used three methods to discern test ball errors and analyzed which could be deemed as the most proper technique in a test of the rotation accuracy of the main spindle of a machine tool.

• Journal of Acupuncture Research
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• v.36 no.4
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• pp.251-255
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• 2019

Background: Low-level laser therapy (LLLT) including laser acupuncture (LA) has been widely used to treat chronic low back pain (CLBP), but there is no critically appraised evidence of the potential benefits. The purpose of this protocol for a systematic review was to enable the evaluation of the effectiveness of LLLT including LA for non-specific CLBP to identify the potential benefits. Methods: The electronic databases MEDLINE (PubMed), Embase (Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL), Korean medical databases (KoreaMed, KMBASE, KISS, NDSL, KISTI, OASIS), the Chinese database (CNKI), and Japanese databases (CiNII, J-STAGE) are recommended. Results: Randomized controlled trials in LLLT including LA should be included in the searches. All data synthesis and subgroup analyses should be conducted using a Review Manager software. The Cochrane risk of bias tool can be used to evaluate methodological quality of the studies. A risk ratio or mean difference with a 95% confidence interval will show the effects of LLLT including LA. Conclusion: The primary outcome would be pain intensity and functional status/disability due to low back pain. The secondary outcome would be a global measurement of recovery or improvement, quality of life and adverse event.

• Journal of Convergence Korean Medicine
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• v.2 no.1
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• pp.23-34
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• 2021

Objectives: This study aimed to review the effects of Daoyin exercise on scoliosis in clinical studies. Methods: In this study, we reviewed 9 electronic databases (Pubmed, CAJ, EMBASE, Cochrane Library, CiNii, KISS, KMBASE, OASIS, ScienceON) on May 22, 2021. We included only randomized controlled trials (RCTs) which evaluated the effect of Daoyin exercise on scolisos. The methodological quality of the included studies was checked using the Cochrane risk of bias tool. Results: After screening, eight RCTs fulfilled the inclusion criteria. The results of the meta-analysis showed that Daoyin exercise improves the measurement value of Cobb's angle, SRS-22, pulmoary function, physiological curvature, muscle strength, effective rate in scoliosis patients. Conclusion: We concluded that Daoyin exercise has therapeutic effects in relief of imbalance, improvement of symptoms, improvement of function, muscle strength for scoliosis. However, the quality of the original articles was low and the number of papers included were few. Thus, to confirm these results, further well-designed RCTs should be conducted.