• 대한기계학회논문집A
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• 제38권8호
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• pp.823-829
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• 2014

본 연구에서는 계면활성제를 첨가한 사각 PDMS(polydimethylsiloxane) 마이크로 채널에서의 모세관 흐름에 의한 충전 길이를 예측하기 위한 모델들을 제안하였다. 일반적으로 PDMS 의 소수성 특성 때문에 모세관 힘만을 이용한 PDMS 마이크로 채널에서의 물의 이동에는 어려움이 따르게 된다. 따라서 본 연구에서는 계면활성제를 첨가하여 친수성을 가지는 PDMS 표면을 제작하고, 이 표면에서의 물의 접촉각 변화 측정 및 단순 모델을 수립하였다. 또한 친수성 PDMS 마이크로 채널에서의 모세관 힘에 따른 충전 길이를 예측하기 위해서 Washburn 방정식을 바탕으로 한 단순 모델을 수립하였다. 그 결과 유체의 충전 길이는 접촉각의 초기변화속도의 영향을 받는 것을 확인할 수 있었다. 이를 바탕으로 대표적인 세가지 경우에 대한 모델을 제안하였으며, 이들은 MIMIC(MIcroMolding In Capillaries)과 같은 마이크로 유체 기반의 생산공정의 설계와 개발에 유용하게 적용될 수 있을 것이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.400-407
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• 1995

The straightness property is one of fundamental geometric tolerances to be strictly controlled for guideways of machine tools and measuring machines. The staightness measurement for long guideways was usually difficult to perform, and it needed additional equipments or special treatment with limited application. In this paper, a new approach is proposed using the profile matching technique for the long guideways, which can be applicable to most of straghtness measurements. An edge of relativelly sthort length is located along a divided section of a long guideway, and the local straightness measurement is performed. The edge is then moved to the next section with several positions overlap. After thelocal straightness profile is measured for every section along the long guideway with overlap, the global straightness profile is constructed using the profile matching technique based on theleast squares method. The proposed techinique is numerically tested for two cases of known global straightness profile arc profile and irregular profile and those profiles with and without random error intervention, respectively. When norandom errors are involved, the constructed golval profile is identical to the original profile. When the random errors are involved, the effect of the number of overlap points are investigated, and it is also found that the difference between the difference between the constructed and original profiles is very close to the limit of random uncertainty with juist few overlap points. The developed technique has been practically applied to a vertical milling machine of moving table type, and showed good performance. Thus the accuracy and efficiency of the proposed method are demonstrated, and shows great potential for variety of application for most of straightness measuirement cases using straight edges, laser optics, and angular measurement equipments.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.107-115
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• 2001

It is required more precise analysis for practical load because of complexities and varieties of vehicle structure. To establish the numerical model, many researchers have been developed designing tools for linking F.E. Analysis results and experimental results. There studies have generally focused on each experimental method or analytical method separately. There are few studies based on both methods. This paper conceives new procedure for the determination of the load direction and magnitude applied on mechanical structures. New procedure is the combination of the analytical and empirical method with analyzed strain by F.E. Analysis under unit load and with measured principal stress by strain gages under driving load, respectively. In this paper, we theorize the procedure of practical load determination and make the validity and the practicality of the procedure with the application to T-shape jointed structure. F.E. Analysis is conducted to get the principal stress on arbitrary points in the F.E. model of T-shape joint under unit load. Then experiment is carried out to get the principal stress on the same points of F.E. model. To demonstrate the actual driving condition, the load conditions are bending and torsion. From these two data sets, the magnitude, the direction and the position of load can be obtained. Theory and practice do not always coincide; since there are some errors such as ill-poseness, measuring error and modeling error in experimental data, we examine the proper method of error minimization.

• 융합신호처리학회논문지
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• 제20권4호
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• pp.193-198
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• 2019

인터넷상에서의 진짜 및 가짜 정보의 범람이 수많은 텍스트 분석에 대한 연구를 이끌었다. 문헌 표기 없이 타인의 저작물을 무단 복제 및 관련 없는 연구결과 조작 등이 한동안 세간의 주목을 이끌었다. 연구 분야에서 표절과 이의 대항 및 감소를 위해 다양한 도구들이 개발되었다. Pearson Spearman 본 연구에서는 코사인 유사성과 및 상관관계를 이용하는 파라미터 및 비 파라미터 방법을 이용하여 문장 유사성을 측정한다. Pearson 코사인 유사성과 상관관계는 가장 높은 유사성 계수를 얻었으나 Spearman 상관관계는 낮은 유사성 계수를 보여주었다. 본 논문에서는 정상성 가정과 편향성에 의존하는 파라미터 방법들에 반하도록 비정상성 가정으로 인한 문장 유사도를 측정하는 데 있어 비 파라미터 방법들을 사용하는 것을 제안한다.

• Journal of Acupuncture Research
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• 제23권5호
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• pp.155-165
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• 2006

Objectives : This study was to examine the effect of Intradermal Acupuncture therapy at Kyeonjeong, Cheonryo and Kokji on the shoulder pain. The research was conducted with non equivalent control group non-synchronized design. Methods :　IThe subjects were the women who was suffering for shoulder pain, who are employed at two hospitals in Busan, from April to June, 2006. The 24 women were experimental group who were applied to Intradermal Acupuncture Therapy at Kyeonjeong, Cheonryo and Kokji, while the 20 women were control group who weren't applied to any treatments. The severity of shoulder pain and the extent of the subjective symptoms of shoulder pain were pre-measured. The Intradermal Acupuncture therapy was done a total of 4 times, 2 times a week over 2 weeks and from 11 a.ｍ. to 2 p.m. as an experimental treatment. As a post survey, the severity of shoulder pain, the frequency of shoulder pain and the extent of the subjective symptoms of shoulder pain were measured after one week and two weeks of experimental treatment. Research tools are Visual Analogue Scale by Cline et al. for measuring the severity of shoulder pain and the tool developed by Japan's industrial fatigue research committee of the industrial hygienics society and modified. Results : There was a significant difference(F=4.132, p=0.019) for the severity of shoulder pain on the interaction between time and group. There was a significant difference(F=11.193, p=0.000) for the extent of the subjective symptoms of shoulder pain on the interaction between time and. group. Conclusion : Based on the above results, it can be determined that Intradermal Acupuncture Therapy at Kyeonjeong, Cheonryo and Kokji can be used as the effective treatments for reducing of shoulder pam.

• 지역사회간호학회지
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• 제18권3호
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• pp.373-381
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• 2007

Purpose: An exercise program, which was composed of motions simple and easy to follow, was developed and applied to aged women as a way to improve their health conditions. Method: To ascertain the effects of the exercise, which was conducted twice a week and 16 times in total for 8 weeks from September 10 to November 5, 2005 in two experimental groups (31 Persons) and a control group (31 persons), this study conducted quasi-experiments of nonequivalent control group pre-post test design. Data were analyzed using SPSS/PC Win 10.0, the reliability of the measuring tools using Cronbach's alpha, the verification of equivalence for general properties and dependent variables using Chi-square test and t-test, and the verification of hypotheses using t-test and ANCOVA. Results: After the exercise program. the aged women showed profitable evaluation of decisional balance, high feeling of self-efficacy as well as improved subjective awareness of health. Their diastolic blood pressure and total cholesterol were also reduced significantly after the exercise. Conclusion: After the conduct of the exercise program for 8 weeks, aged women showed increased profitable decisional balance, self-efficacy and subjective awareness of health. This suggests that continuous and proper exercise is effective as an intervention for health improvement for the aged as well as the prevention of and recovery from geriatric diseases.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.81-89
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• 2021

This study aimed to investigate the factors affecting Logistics capabilities for Logistics Service Providers in Vietnam. Researchers inherited and developed based on previous research to focus on analyzing and evaluating dynamics, measuring Logistics capabilities, and the factors affecting Logistics capabilities for Logistics Service Providers. The logistics capabilities Model is used based on three factors: customer demand management capability, innovation capability, and information management capability. The empirical analysis used data from the survey data of l90 managers of Logistics Service Providers in Hai Phong, Ho Chi Minh City, Da Nang, Hue, Hanoi with reliable tools (SPSS 26.0 software). The data were analyzed by frequencies, percentages, means, Pearson's Linear Correlation Coefficient, exploratory factor analysis, and multi-linear regression model based on the survey data. The research results identified the following factors affecting Logistics capabilities for Logistics Service Providers: innovation capability has the strongest impact on Logistics capabilities; customer demand management capability has the following strong effects on Logistics capabilities; and finally, information management capability that affects Logistics capabilities. There is also a positive relationship between all factors and Logistics capabilities. Several recommendations are further suggested to enhance to improve Logistics capabilities for Logistics Service Providers in Vietnam.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제36권4호
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• pp.589-610
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• 2022

본 연구는 2023년부터 적용 예정인 6학년 2학기 검정 교과서를 대상으로 초등 수학에서 원주율 개념을 어떻게 지도하고 있는지를 비교·분석하여 교수학적 시사점을 도출하고자 하였다. 이를 위해 원주율 개념과 원주율 지도에 관한 선행연구를 분석하여 분석 기준을 마련하였으며, 개념 추론하기, 속성 이해하기, 관계 적용하기의 교수·학습요소로 나누어 살펴보았다. 분석 결과를 통해, 어림 활동이 원주율 개념의 추론 활동으로 연결되기 위한 다양한 어림 맥락의 개발이 필요하다는 것과 지름과 원주를 실제로 측정을 해야 하는 동기를 제공하는 문제 상황의 제시, 지름을 단위로 하여 원주 위를 반복하여 세는 측도의 속성을 탐구할 수 있는 기회의 제공, 원주율의 상수 속성의 명시화, 상황에 따라 원주율의 근삿값 선택의 유연함을 경험하게 할 것을 시사점으로 제시하였다. 이상의 결론과 교수학적 시사점을 바탕으로 원주율의 도입 맥락과 공학 도구 활용에 초점을 맞추어 초등 수학에서 원주율 개념의 지도 방안과 향후 2022 개정 교육과정에 따른 교과서 개발에 개선점을 제안하였다.

• 대한통합의학회지
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• 제11권1호
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• pp.31-41
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• 2023

Purpose : This study was conducted to identify the common characteristics of older persons with sarcopenia and to explore the relationship between gait, balance, and stress using an integrated assessment tool. Methods : In this study, 95 people aged 65 years or older were screened using the sarcopenia diagnostic evaluation algorithm presented by the Asian Working Group for Sarcopenia in 2019. Skeletal muscle index, grip strength, and short physical performance battery were used as sarcopenia evaluation measurements. Based on the results of this evaluation, participants were grouped into the 'non-sarcopenia group' (41 participants) or the 'sarcopenia group' (54 participants). Participants underwent further assessment using an integrated evaluation tool capable of measuring gait, balance, and stress. Gait ability was evaluated using the timed up and go test, and balance ability was evaluated using the berg balance scale. And the stress of the last month was measured by modifying the stress index developed by a Korean researcher. Collected data were statistically analyzed using the independent t-test and Mann Whitney-U test. Results : The sarcopenia group and the non-sarcopenia group showed significant differences in all elements of the sarcopenia diagnostic evaluation. There were significant differences in all three integrated evaluation tools. For the evaluation of walking ability, the time measured in the timed up and go test was longer in the sarcopenia group, the berg balance scale score for the evaluation of balance ability was lower in the sarcopenia group, and the stress index was higher in the sarcopenia group. Conclusion : Through sarcopenia analysis using an integrated evaluation tool, it was confirmed that sarcopenia is closely related to decreased walking ability, poor balance, and increased stress. We recommend using this tool to reduce the risk of sarcopenia progression and stress exposure through the planning and implementation of an exercise program for sarcopenia prevention.

• 한국표면공학회지
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• 제34권5호
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• pp.414-420
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• 2001

A 30-kV plasma immersion ion implantation setup (P $I^3$) has been equipped with a self-developed 6'-magnetron to perform hard coatings with enhanced adhesion by P $I^3$D(P $I^3$ assisted deposition) process. Using ICP source with immersed Ti antenna and reactive magnetron sputtering of Ti target in $N_2$/Ar ambient gas mixture, the TiN films were prepared on Si substrates at different pulse bias and ion-to-atom arrival ratio ( $J_{i}$ $J_{Me}$ ). Prior to TiN film formation the nitrogen implantation was performed followed by deposition of Ti buffer layer under A $r^{+}$ irradiation. Films grown at $J_{i}$ $J_{Me}$ =0.003 and $V_{pulse}$=-20kV showed columnar grain morphology and (200) preferred orientation while those prepared at $J_{i}$ $J_{Me}$ =0.08 and $V_{pulse}$=-5 kV had dense and eqiaxed structure with (111) and (220) main peaks. X-ray diffraction patterns revealed some amount of $Ti_{x}$ $N_{y}$ in the films. The maximum microhardness of $H_{v}$ =35 GN/ $M^2$ was at the pulse bias of -5 kV. The P $I^3$D technique was applied to enhance wear properties of commercial tools of HSS (SKH51) and WC-Co alloy (P30). The specimens were 25-kV PII nitrogen implanted to the dose 4.10$^{17}$ c $m^{-2}$ and then coated with 4-$\mu\textrm{m}$ TiN film on $Ti_{x}$ $N_{y}$ buffer layer. Wear resistance was compared by measuring weight loss under sliding test (6-mm $Al_2$ $O_3$ counter ball, 500-gf applied load). After 30000 cycles at 500 rpm the untreated P30 specimen lost 3.10$^{-4}$ g, and HSS specimens lost 9.10$^{-4}$ g after 40000 cycles while quite zero losses were demonstrated by TiN coated specimens.s.