• Korean Journal of Plant Resources
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• v.8 no.3
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• pp.297-302
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• 1995

The experiment is conducted to reduce the labor and production cost with the labor save of harvest if cultivating the potatoes using the machine and the results are as follows. On labor saving effect in transparent vinyl mulching, digging working hours per 10a in the case of using tractor are 60 min., fixing + turning time is 5 min. and 30sec., the time of harvest is 65 min and 30sec., digging working hours using cultivator are 99 min. and fixing +turning time is 5 min. and 30sec., but the time of hand harvesting is 990 min. and in digging labor saving effect, tractor shows 94% in the harvesting period and harvest by cultivator 90%. On non mulching cases, the harvest by tractor takes 49 min. and 30 sec. and that by cultivator does 87 min. and 30 sec., and digging labor saving effect shows 94% in the tractor harvest and 90% in the cultivator harvest. Therefore, on the operation efficiency per hour, in the case of tractor with digger vinyl mulching and non mulching show, $0.091\sim0.121ha$ and in the case of cultivator with digger both show $0.057\sim0.069ha$, so in the mechanized harvest of potatoes, the harvest by tractor with digger is the best. On the cost and labor save for harvesting the potatoes with labor saving effect, tractor shows 19 hours and 20 min./10a in vinyl mulching and 19 hours. and 54 min./10a in non mulching, so it shows the short hours for harvesting. And labor saving effect shows $42\sim45%$ in comparison with 35 hours and 21 min. $\sim35$ hours and 23 min.($123,113\sim130,613$ won) of the hand harvest, so the cost was reduced to $71,250\sim72,225$ won. On the cultivator with diggers, vinyl mulching takes 19 hours and 55 min. and non mulching 19 hours and 38 min., so the labor saving effect and cost were reduced to $14\sim44%$ ($72,675\sim73,313$ won) in comparison with the hand harvest.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.247-253
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• 2012

The purpose of this study was to conduct phenology monitoring of forest plant species in Mt. JuWang National Park, thereby establish long-term prediction and management system for species susceptible to climate change, and utilize the result as basic materials necessary for conservation of plant genetic resources in accordance with changes in their growth environment. Global Positioning System coordinates were marked on each indicator species and a specific number ticket was provided to each plant. Changes in their blooming time, time of blossoms falling, time of leaves bursting into life, and time of leaves turning, and time of leaves falling were recorded. Investigation was made once per week from April 10 in 2010 to November 30 in 2011 except for the time period between July and August when investigation was made biweekly. The investigated plants concerned 12 kinds-nine species of trees and three kinds of herbs. According to the result of the penology monitoring of Mt. JuWang National Park, their time of leaves bursting into life, time of leaves turning, and time of leaves falling were largely earlier in 2011 than in 2010. However, it is hard to say that it is due to the factor of climate change. Long-term collection of climate data and continuous monitoring of plant phenology are considered necessary in order to examine correlation between climate change and seasonal change patterns of plants.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.164-169
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• 1998

This paper deals with condition monitoring for tool wear during tuning operation. To develop economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. To identify noise sources of tool wear and reject background noise, noise rejection methodology is proposed. features to represent condition of tool wear are obtained through analysis using adaptive filter and FFT in time and frequency domain. By using fuzzy pattern recognition, we extract features, which are sensitive to condition of tool wear, from several features and make a decision on tool wear. The validity of the proposed system is condirmed through the large number of cutting tests in two cutting conditions.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.886-896
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• 1991

In this paper a new turning gait is proposed for a quadruped walking robot. The proposed scheme makes it possible to control the translation and orientation of the walking robot simultaneously. At first the feasible leg sequences which can guarantee a positive longitudinal gait stability margin for each direction of movement are found. A method for finding the lifting time of each leg of a feasible leg sequince and selecting an optimal gait among feasible gaits is then suggested. The proposed gait can be appled to control the posture of walking robots and to generate an optimal gait for a desired movement of translation and rotation of the walking robot systematically.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.675-680
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• 2009

Because of high specific stiffness, the aluminum alloy has been used for various industry field. Specially, the heat-treated aluminum alloy is difficult-to-machine material and machining test is necessary to evaluate and improve the machinability. In order to manufacture the functional part, appropriate cutting condition is selected by considering surface quality, machining time, and workpiece deflection by cutting force. In this investigation, the machinability of A16061-T6 is estimated by changing cutting conditions. The variable cutting conditions are cutting speed, depth of cutting, and feed rate. The estimation is done by analysis of cutting force, surface roughness, and surface shape according to the change of cutting conditions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.102.2-102
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• 2001

In this study, a solid-state laser system adopting a new real time multi-discharge (RTMD) method in which three flashlamps are turned on consecutively was designed and fabricated to examine the pulse width and the pulse shape of the laser beams depending upon the changes in the lamp turn-on time. That is, this study shows a technology that makes it possible to make various pulse shapes by turning on three flashlamps consecutively on a real-time basis with the aid of a PIC one-chip microprocessor, With this technique, the lamp turn-on delay time can be varied more diversely from 0 to 10 ms and the real-time control is possible with an external keyboard, enabling various pulse shapes. In addition, longer pulses can be more widely used for industrial processing and lots of medical purposes.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.21-26
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• 1992

Generally a navigator evaluated the maneuverability of his ship by the scale of turning circle which was described only by the largest rudder angle of the port and starboard sides. But to have the sufficient knowledge of his ship's maneuvering characteristics he should consider the data about the new course keeping test, the spiral test, and the turning circle tests in accordance with the rudder angles together. In this paper the author performed the above tests to study the maneuverability of the stern trawler M.S. Pusan 404 which is a training ship of the National Fisheries University of Pusan. The obtained results are summarized as follows: 1. When the rudder angles being 5。, 10。, 20。, 30。, 35。 the advances of the starboard side turning circles were 12.8, 8.2, 4.8, 2.9, 2.7 times as large as the length of the ship, and of the port side turning circles were 13.3, 8.7, 5.4, 3.5, 2.9, time as large as the large as it. Under the same conditions the tactical diameters were 15.1, 9.7, 5.2, 3.1, 2.8 times as large as the length of the ship, for starboard side, and 17.2, 12.4, 6.4, 3.7, 3.2 times as large as it for port side. 2. As the rudder angle being increased the ratio of the advance to the tactical diameter was nearly 1 and her obeying ability was better than that of the small angle. 3. The mean values of the rates of speed reduction during the steady turning motion were 0.96, 0.92, 0.82, 0.71, 0.65 in accordance with the rudder angles. 4. The relative formulas between the distance to the new course y and the altering course x were as follows: When rudder angles being 10。, 20。, 30。, y=52.2222+1.6133x, y=48.750+0.9383x, y=39.250+0.655x respectively. 5. There was little difference of the distance to the new course between rudder angle 20。and 30。, and so it is desirable for a navigator to a navigator to use the small rudder angles unless sudden emergencies. 6. Though her rudder angle being small her course stability was good according to the spiral tests.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1807-1809
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• 2002

In this study, asolid-state laser system adopting a firing time control(FTC) method in which three flashlamps are turned on consecutively was designed and fabricated to examine the pulse width and the pulse shape of the laser beams depending upon the changes in the lamp turn-on time. That is, this study shows a technology that makes it possible to make various pulse shapes by turning on three flashlamps consecutively on a real-time basis with the aid of a PIC one-chip microprocessor With this technique, the lamp turn-on delay time can be varied more diversely from 0 to 10 ms and the real-time control is possible with an external keyboard enabling various pulse shapes. In addition longer pulses can be more widely used for industrial processing and lots of medical purposes.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.114-120
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• 2010

Optimization of the turning process has been concentrated on the selection of the optimal cutting parameters, such as cutting speed, feed rate and depth of cut. However, optimization of the cutting parameters does not necessarily guarantee the maximum profit. For the maximization of the profit, parameters other than cutting parameters have to be taken care of. In this study, 8 price-related parameters were considered to maximize the profit of the product. Regression equations obtained from RSM technique to relate the cutting parameters and maximum cutting volume with a given insert were used. The experiments with four combinations of cutting inserts and material were executed to compare the results that made the profit and cutting volume maximized. The results showed that the cutting parameters for volume and profit maximization were totally different. Contrary to our intuition, global optimization was achieved when the number of inserts change was larger than those for volume maximization. It is attributed to the faster cutting velocity, which decreases processing time and increasing the number of tool used and the total tool changing time.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.165-174
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• 2007

The subject of this study was male apparatus gymnastics athlete who had scored high points doing basket with 1/2 turn on parallel bars. Then 3D motion analysis were used to calculate & analyse kinematic variables of Basket with 1/2 turn to Handstand. 1. The total average time spent for Basket with 1/2 turn took $2.16{\pm}.08sec$, at the downward upward phase took $.58{\pm}0.00sec$, $.23{\pm}.00sec$, at flight phase took $.28{\pm}.01sec$, at connected area phase took $.72{\pm}0.21sec$, at rotation area phase took $.35{\pm}.14sec$. To have a successful performance, there should be faster speed and velocity to rotate at the downward upward phase, then the upward velocity and height must be used adequately. Moreover, the speed must be faster at the flight connect phase to stabilize Center of Mass(CM) for the body, and must secure more time at the rotation area to have more stable performance. 2. After handstand on parallel bars while moving CM to right hand side, and It must be performed with big and magnificent performance with putting both hand's center to far away from the parallel bars. 3. Furthermore, CM must be moved fast from downwards to right hand side, and CM must be moved fast in vertical movement at upward and flight phase to avoid CM from moving back and forth, and left and right. 4. At downwards, the subject must rotate as bis as possible using hip-joint as wide as possible and at upwards, must put his body to vertical to have stable performance. While rotating or turning, it is better to do with bigger shoulder angle and have to make sure that trunk angle must be not scattered. To perform better and more positive in basket with 1/2 turn on parallel bars, the centrifugal force must be used big and fast at downward, and at upward and flight phase, downward movement must change to vertical movement as soon as possible while turning movement must happen at handstand position. Time spent must be shorten at connected area to stabilize CM and turning must be natural as possible while securing the necessary time of movement to well-balanced. Also, the body must be vertically closed from the ground.