• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.159-164
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• 2000

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.269-278
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• 2017

Objective: The purpose of this study was to develop a goal setting method for increasing the probability of a holed in a side inclined putting stroke. Method: Three-dimensional video data was recorded at a frequency of 120 hz per second after synchronizing 19 infrared motion capture systems (Qualisys, Gothenburg, Sweden). Putting green used a polycarbonate plate ($1.2{\times}2.4{\times}0.01meter$) with coefficient of friction (${\mu}=0.062$) and a real curve of the actual hole. Results: The velocity ratio between the club and the ball was 1:1.6 under various ball speed conditions in this study. The overall position of the break is 1 m to 1.4 m from the point where the ball leaves. If there is a slope, the ball follows the target line by the straightening force, and when it reaches 1 m position, the straightening force decreases by 30~50% and reaches to the deviation (break) point which is severely influenced by the slope. From here, the ball is aimed in a direction other than the target, and the size is affected by the slope. Conclusion: If there is a side slope, the ball moves away from the straight line, and the larger the slope, the closer the break point is to the starting point of the ball. Therefore, it is necessary to calculate the degree of departure according to the slope carefully, and it is preferable that the slower the speed is, the more the influence of the slope becomes. It is preferable to use the center of the hole as a reference when calculating the departure.

• Journal of Biosystems Engineering
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• v.28 no.5
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• pp.395-402
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• 2003

Standard ginseng seedling, selected after one year's rearing in the seedling bed has been conventionally transplanted in Korea. Recently, the direct seeding areas have been increasing to product high quality ginsengs for red-ginseng processing. Reciprocating push-rod brush, holed-roller and vacuum suction seeders, planting with 30 ${\times}$ 30mm spacings and adjustable to the folds were designed and theirs performances were evaluated. The developed three types of seeders reliably performed at the success rate over 95% with less than 10% in slip rate, and could be used a seeder for the greater spacings by adjusting metering parts. The research concluded that the vacuum suction seeder was the most feasible and practical with the greatest metering success and the least slip among three type seeders of the reciprocating push-rod brush, holed-roller and vacuum suction seeders. The vacuum suction seeder holds a seed with each needle nozzle using the negative pressure created by a vacuum pump. The capacity was 24.5 times greater than a man power at the speed of 5 m/min.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.6
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• pp.722-733
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• 1999

The wall pressure fluctuations of a turbulent boundary layer over a flat plate have been investigated in an anechoic wind tunnel facility. The anechoic wind tunnel consists of acoustically-lined duct, muffler, and splitter-type silencer for noise suppression and vanes for reducing head losses involved. To improve spectra characteristics in high frequency range, a 1/8" pressure-type microphone sensor, which has a pin-holed cap of various diameters, was employed in this experiment. It was shown that the pin-holed microphone sensor with a dimensionless diameter $d^+$ of 7.1 resolved the high frequency pressure fluctuations most effectively among ones with various pin-hole diameters. The measured wall pressure spectra in terms of three types of scaling parameters were in good agreement with other experimental and numerical results. The pressure events of high amplitude were found to contribute to total fluctuating pressure energies in the turbulent boundary layer significantly and supposed to radiate to the far-field effectively.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.63-70
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• 2010

We developed a new punching system that generates pinholes expressing texts or images on a plastic plate. The pin-holed plate is used as a new glamorous display board reflecting colorful lights from the light emitting diode (LED) installed on the edge side of the plate. The four degree-of-freedom punching system was designed to make same multiple holes on four plastic plates simultaneously. For this motion, we designed a structure for a simultaneous motion of the system. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, fast motion including precise position control is very important. We also built a PC-based integrated control system including a GUI program to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and position control of the pin holes on the plate.

• Journal of the Korean Society for Railway
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• v.5 no.2
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• pp.118-124
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• 2002

The failure probability of wheel beyond 10$\^$7/ cycles is achieved by the strengths-stress interference model for the evaluation of fatigue strength and reliability in the wheel, From plane bending fatigue test results, the fatigue life (N$\_$f/) for the smooth and 200㎛ holed specimens can be represented as $\sigma$$\_$a/ = 1326N$\_$f/$\^$-0.10/ and $\sigma$$\_$a/ = 2894N$\_$f/$\^$-0.18/. Respectively, fatigue strength of the wheel at beyond 10$\^$7/cycles was about 332 MPa. And, the fatigue strength for the specimen with a micro hole (d=200㎛) which simulated an inclusion on the wheel surface was about 235 MPa. Thus, a micro hole (d=200㎛) caused about 30% reduction of fatigue strength of the specimen. The failure probabilities for the smooth and micro-holed specimens, derived from the strength-stress interference model, are 0.0148% and 13.05%, respectively. The current finding suggests that at least 200 ㎛ sized inclusion, which might be produced during manufacturing process, will cause a critical effect on integrity of the railway vehicle.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.39-40
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• 2009

This study is for development the anchorage that for development and practicality a holed precast prestressed concrete girder for forming an I-type Prestressed concrete girder bridge, in which at least one hole is formed in a body portion of the I-type Prestressed concrete girder.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.711-717
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• 2010

In this paper, a new automatic punching system that generates pinholes expressing texts or images on a plastic plate is developed. The pin-holed plate is used as a new glamorous display board reflecting colourful lights from the light emitting diode (LED) installed on the edge side of the plate. The punching system has four actuators which work together to make multiple holes with accurate position and depth on the plastic plate. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, we developed an accurate actuating structure of the system cooperating with a PID control algorithm. We also built a GUI-based integrated control system to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and depth control of the pin holes on the plastic plate.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1327-1334
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• 1988

In this study rotating bending fatigue tests have been carried out with the deep non-through radial holed notch specimens of low carbon steels(SM 22C). It is investigated that the behaviors of surface and interior fatigue crack propagation and the variations of the shape of the cracked surface on the magnitude of bending stresses. The Obtained results are summarized as follows. (1) The relations between [Crack length] and [Cycle ratio] are expressed by following eq. in the 0.1~0.6 range of N/ $N_{f}$ long[ crack length] = A + B [N/ $N_{f}$ ] In case of surface crack length, values of A and B are uniformed independent upon the magnitude of bending stress, but those are variable according to the magnitude of bending stress for interior crack length. (2) The following eq. is derived on the surface crack propagation rate, bending stress and surface crack length. (dl/dN)=(3.94*10$^{-12}$ ).sigma.$^{4.54}$l (3) Under small stress, interior crack propagation rate increase with the interior crack growth but it decrease for large stress. (4) The shape of cracked surface depends upon the magnitude of bending stress. Under small stress fatigue crack propagates as an semi-ellipse with semi-major axis of surface crack length with semi-major axis of interior crack length for large stress.s.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.54-62
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• 2005

This Study is to find out how RC beam mixed with sawdust acts comparing with normal beam without sawdust mixture, and how they can be applied to the actual structural frame, despite a Int that they are mixed with waste material : saying sawdust. ED3H1, ED3H2, ED5H1, ED5H2, ED3H1UB, ED5H1UB, ED3H2L, ED5H2L and Normal without sawdust mixture are main factor to be tested here in order to apply them to the actual case. D and H means diameter 3cm or 5cm, and holes one and two respectively. And all variables are tested with each two for one variables. Test results are compared using crack diagrams and strain & loads. There are eleven(11)% capacity decrease between ED 3H1 and ED5H1 in rebar, strain. Left and right side crack shapes are much similar in variable ED3H2L having maximum capacity 14.5 tone. ED5H2L having maximum capacity thirteen(13)tone, in case of normal 19.6 tone. Two holes in beam rather on the longitudinal direction than on the forcing direction can be more effective to keep the original capacity of the beam because this case can distribute load more uniformly. There is 33% capacity decreased in case of diameter five(5)cm, compared to diameter three(3)cm. Two holes give thirty nine(39) percent capacity decrease than one of diameter three(3)cm.