• 한국산림과학회지
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• 제95권1호
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• pp.1-4
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• 2006

고로쇠나무 수액채취시 천공으로 인한 수목의 피해 여부를 판단하기 위해 천공수별로 수액채취 후의 유합과정과 직경생장을 조사하였다. 유합은 조사기간 동안 천공 수 10개소인 임목이 천공 수 1 개소, 3개소, 5개소인 임목보다 빠르게 이루어졌으며 자연상태에서 천공은 15개월만에 모두 유합되었다. 천공 수별 직경생장은 각각 무처리가 0.54 mm, 1개소가 0.60 mm, 3개소가 0.64 mm, 5개소가 0.33 mm, 10개소가 0.31 mm로 나타났다. 유합재료별 유합과정은 DB도포제, 스티로폼, 무처리, 죽초액의 순으로 진행되었으며, DB도포제를 처리했을 경우의 천공은 4개월 만에 유합되는 것으로 나타났다. 그러므로 천공으로 인한 고로쇠나무의 피해를 최소화하고 지속적인 수액자원을 확보하기 위해서는 DB도포제를 이용하여 빠른 기간 내에 천공이 유합되도록 하여야 할 것으로 사료된다.

• 한국기계가공학회지
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• 제11권3호
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• pp.24-28
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• 2012

In this paper, the high speed milling characteristics of Al6061 was studied. A gantry type milling & tapping center was developed for this study. The cutting force and the resulting surface roughness were measured at various cutting conditions. The experimental results indicate that the surface roughness is relative to the cutting conditions.

• 제어로봇시스템학회논문지
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• 제22권4호
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• pp.307-314
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• 2016

Recently, demands on the tapping machine are increased due to the case of a cell phone is changed to metal such as aluminum. The automatic tool changer (ATC) is one of the most important devices for the tapping machine related to the speed and energy consumption of the machine. To reduce the consumed energy and vibration, the dynamic modeling is essential for the ATC. In this paper, inverse dynamic modeling of a novel ATC mechanism is introduced. The proposed ATC mechanism is composed of a double four-bar mechanism with a circular tablet to generate continuous rotation of the tablet. The dynamic modeling is performed based on the Lagrange equation with a modeling for the contact between the four-bar and the tablet. Simulation results for various working conditions are proposed and analyzed for the prototype design. The dynamic modeling can be applied to determine the proper actuator and to reduce the vibration and consumed energy for the ATC machine.

• 대한물리의학회지
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• 제18권2호
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• pp.1-11
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• 2023

PURPOSE: This study examined the immediate effects of applying ankle eversion taping using kinesiology tape in chronic stroke patients-design: a randomized cross-over trial. METHODS: Seventeen stroke patients underwent three interventions in random order. The subjects were initially assigned randomly to an ankle eversion taping, placebo taping, or no taping for each intervention. Ankle eversion taping was used for mechanical correction and was involved in ankle dorsiflexion and eversion. The tape was stretched by 30-40%. Placebo tapping was applied in the same form as eversion tapping but was not stretched. The balance ability was assessed using the Y-balance test. The gait ability was assessed by maximum foot pressure and time of stance phase, and gait speed was assessed using a 10 m walk test (10MWT). All measurements were performed immediately after the intervention. RESULTS: The results showed that the dynamic balance and stance phase time in chronic stroke patients was improved after ankle eversion taping. The ankle eversion taping conditions increased significantly (p < .05) compared to the placebo and no taping conditions. CONCLUSION: The application of ankle eversion taping that uses kinesiology tape instantly increased the gait ability of chronic stroke patients. On the other hand, more research will be needed to identify the long-term effects of ankle eversion taping.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.369-372
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• 2002

In this research, a vision system for detecting tool breakage which is hardly detected by such indirect in-process measurement method as acoustic emission, cutting torque and motor current was developed and embedded into a PC-NC system. The vision system consists of CMOS image sensors, a slit beam laser generator and an image grabber board. Slit beam laser was emitted on the tool surface to separate the tool geometry well from the various obstacles surrounding the tool. An image of tool is captured through two steps of signal processing, that is, median filtering and thresholding and then the tool is estimated normal or broken by use of change of the centroid of the captured image. An air curtain made by the jetting high-pressure air in front of the lens was devised to prevent the vision system from being contaminated by scattered coolant, cutting chips in cutting process. To embed the vision system to a Siemens PC-NC controller 840D NC, an HMI(Human Machine Interface) program was developed under the Windows 95 operating system of MMC103. The developed HMI is placed in a sub window of the main window of 840D and this program can be activated or deactivated either by a soft key on the operating panel or M codes in the NC part program. As the tool breakage is detected, the HMI program emit a command for automatic tool change or send alarm to the NC kernel. Evaluation test in a high speed tapping center showed the developed system was successful in detection of the small-radius tool breakage.

• Journal of Preventive Medicine and Public Health
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• 제27권3호
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• pp.487-504
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• 1994

A cross-sectional study was performed to evaluate the effects of chronic low-dose solvent on neurobehavioral performance of 118 male car painters. A control group of 113 workers matched for age was selected from different sections of the factory. The mean age and the mean duration of employment were 33 years and 6.7 years in both groups. Mean years of education were 11.4 years in car painters and 11.8 years in controls. Each worker completed a medical and occupational questionnaire and four tests of Swedish performance evaluation system. These included simple reaction time, symbol digit, digit span and finger tapping speed. Althougth the mean duration of employment was 6.7 years, comparison of mean performance showed a significantly poorer performance on simple reaction time (p<0.05), symbol digit(p<0.01) and digit span(p<0.05) in car painters. In univariate analysis, age and educational level contributed to poorer performance on symbol digit and digit span. Smoking appeared to slow finger tapping speed in car painters. Performance of four tests of car painters exposed to high level of solvent was poorer than that of car painters exposed to low level. In multiple regression models, controlling for age, alcohol, smoking and shift work, solvent exposure was found to be associated with performance of simple reaction time, symbol digit and digit span and exposure to high level of solvent was related to poorer performance of symbol digit and digit span.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.869-877
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• 2016

Necessity has compelled man to improve upon the art of tapping wind energy for power generation; an apt reliever of strain exerted on the non-renewable fossil fuel. The power generation in a Wind Farm (WF) depends on site and wind velocity which varies with time and season which in turn determine wind power modeling. It implies, the development of an accurate wind speed model to predict wind power fluctuations at a particular site is significant. In this paper, Box-Jenkins ARIMA (Auto Regressive Integrated Moving Average) time series model for wind speed is developed for a 99MW wind farm in the southern region of India. Because of the uncertainty in wind power developed, the economic viability and reliability of power generation is significant. Life Cycle Costing (LCC) method is used to determine the economic viability of WF generated power. Reliability models of WF are developed with the help of load curve of the utility grid and Capacity Outage Probability Table (COPT). ARIMA wind speed model is used for developing COPT. The values of annual reliability indices and variations of risk index of the WF with system peak load are calculated. Such reliability models of large WF can be used in generation system planning.

• Journal of Yeungnam Medical Science
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• 제14권1호
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• pp.183-196
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• 1997

유기용제가 신경행동기능에 미치는 영향을 평가하기 위하여 에탄올을 이용하여 저농도의 유기용제가 신경행동기능에 미치는 영향을 정량적으로 평가하고 신경행동기능 영역중 에탄올에 민감한 기능영역을 선별하기 위하여 실험연구를 시행하였다. 영남대학교 의과대학 학생중 20명을 대상으로 설문조사 및 신경행동학적 검사를 1996년 8월동안 실시하였다. 대상자의 체중 kg당 100% 알코올 0.5g을 섭취하고 개인용 컴퓨터를 이용하여 단순반응시간, 색단어구분, 숫자구분, 손가락두드리기, 숫자더하기, 부호숫자짝짓기, 숫자외우기를 시행하였다. 알코올 섭취 전과 후의 신경행동기능의 변화량은 단순반응시간(반응시간 237.4 : 269 msec, p<0.01), 숫자구분(반응시간 490.4 : 553.9 msec, p<0.01), 우수의 손가락두드리기(반응시간 66.7 : 63.3, p<0.05)와 부호숫자짝짓기(반응시간 1958.7 : 2066.6 msec, p<0.05)에서 통계적으로 매우 유의하였다. 평소 음주량이 많을수록 단순반응시간, 열수의 손가락두드리기, 부호숫자짝짓기에서는 반응시간이 길어지고, 우수의 손가락두드리기에서 두드린 수가 적어지는 경향을 보였다. 흡연량이 많을수록 열수의 손가락두드리기에서 두드린 횟수가 증가하는 경향을 보였다(p<0.05). 알코올의 급성폭로 후 나타난 결과로 만성적 폭로의 영향을 평가하는데 이용하기에는 다소 무리가 있으나 향후 유기용제의 만성효과에 관한 역학적 연구를 위한 신경행동학적 검사항목의 선택에 도움을 줄 수 있을 것으로 생각된다.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.111-111
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• 2001

목적： To evaluate the feasibility of the event-related functional MR study using power grip studying the hand motor system 대상 및 방법： Event-related functional MRI was performed on a 1.5T MR unit in seven norm volunteers (man=7, right-handedness=2, left-handedness=5, mean age： 25 years). A single-shot GRE-EPI sequence (TR/TE/flip angle： 1000ms/40ms/90, FOV = 240 mm matrix= 64$\times$64, slice thickness/gap = 5mm/0mm, 7 true axial slices) was used for functiona MR images. A flow-sensitive conventional gradient echo sequence (TR/TE/flip angl 50ms/4ms/60) was used for high-resolution anatomical images. To minimize the gross hea motion, neck-holders (MJ-200, USA) were used. A series of MR images were obtained in axial planes covering motor areas. To exclude motion-corrupted images, all MR images wer surveyed in a movie procedure and evaluated using the estimation of center of mass of ima signal intensities. Power grip task consisted of the powerful grip of all right fingers and hand movement ta used very fast right finger tapping at a speed of 3 per 1 second. All tasks were visual-guid by LCD projector (SHARP, Japan). Two tasks consisted of 134 phases including 7 activatio and 8 rest periods. Active stimulations were performed during 2 seconds and rest period were 15 seconds and total scan time per one task was 2 min 14 sec. Statistical maps we obtained using cross-correlation method. Reference vector was time-shifted by 4 seconds an Gaussian convolution with a FWHM of 4 seconds was applied to it. The threshold in p val for the activation sites was set to be 0.001. All mapping procedures were peformed usin homemade program an IDL (Research Systems Inc., USA) platform. We evaluated the activation patterns of the motor system of power grip compared to hand movement in t event-related functional MRI.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.899-904
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• 2001

The impact of PVD coatings can be summed up in practical terms: this technology historically complements the best designed tool substrates to enhance cutting performance. PVD coatings are now incorporated in 25% of all HSS tools. The functionality is to extend the machining speed range, improve wear resistance at the cutting edge, and reduce friction at chip/tool contact areas to allow easier chip evacuation. These translate to a larger safe zone, as discussed in the failure mode diagram, for better productivity and higher reliability in machining operations of the customer. PVD coatings therefore represent an enabling technology that extends the application range of cutting tools in response to modern industrial needs. PVD coatings prolong the product life cycle of HSS tools and help this "mature" material to hold its territory against the advent of the newer hardmetal and ceramic tool materials. There is a lot of competitive life left particularly in PVD coated HSS endmills, drills, threading/tapping tools. PM HSS technology further increases the possibilities.ibilities.