• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.792-801
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• 1996

A thinning algorithm -based image analysis technique was developed to measure corn root lengths. The root length measurement method was evaluated by comparing thread lengths measured by the image analysis system with actual thread lengths. The length measurement method accurately estimated actual thread lengths (less than 2% calculated error). Also, a rapid root length density measurement procedure, which utilizes the above root length measurement method, was developed to estimate corn root length density without washing the roots. Root length densities estimated from the cut soil surface of core samples taken from the field were paired with the root length densities determined from washed roots from the same soil core sample. A linear relationship between these two values was expected and was found. Eliminating the root washing procedure reduces the time required for measuring corn root length density substantially.

• Tunnel and Underground Space
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• v.11 no.3
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• pp.248-256
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• 2001

The cylindrical cut is most frequently used in tunnel blast regardless of their dimensions. In this study the new parallel cut is proposed to raise advance per round, which is considered to be an elevation of the traditional cylinder cuts. The general geometric pattern of a new cut with parallel blast holes is proposed. The detailed burden and spacing between the central blasthole and those of the four section are also given. The blast results between new cut and traditional cylinder cut are given. The main results of this study are as follows. 1) The average advances per rounds in new cuts can reach 99.5% of drilling length. That of traditional cylinder cuts are known approximately 90∼95% 2) Specific charge weight of new cut compare to that of cylinder cut is approximately reduced 5% from 1.363 to 1.297 kg/㎥ 3) Specific drilling rate is also reduced 8% from 2.393 to 2.130 m/㎥ 4) Vibrations, fly rock, and fragmentation produced by the new blast are to be proved superior to those of the traditional cylinder cuts.

• Journal of Biosystems Engineering
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• v.24 no.1
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• pp.67-74
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• 1999

A prototype cut-flower sorter was developed and tested for its performance with five varieties of roses. Support plates driven by a chain mechanism transported the roses into an image inspection chamber. Color image processing algorithms were developed to evaluate the length, thickness, and straightness of stem and color, height, and maturity of bud. The average absolute errors of the system for the measurements of stem length, stem thickness, and height of bud were 19.7 mm, 0.5 mm, and 3.8 mm, respectively. The results of classification by the sorter were compared with those of a human inspector for straightness of stem and maturity of bud. The classification error for the straightness of stem was 8.6%, when both direct image and reflected image by a mirror were analyzed. The accuracy in classifying the maturity of bud varied among the varieties, the smallest for‘Nobless’(1.5%) and the largest for‘Rote Rose’(13.5%). The time required to process a rose averaged 2.06 seconds, equivalent to the capacity of 1,600 roses per hour.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1114-1121
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• 2000

A flexible disk grinding process model was developed based on the dynamic relationship proposed by Kurfess and the influence of the major system parameters which potentially affect the grinding process was studied. Due to the process complexities, several new parameters were assumed to be kinematically dependent on the geometric layouts of the process. Different process stages had been defined depending on the kinematic relationships between the grinding disk and workpiece. A trend of depth of cut was simulated using the proposed model and compared with the empirically measured data in two dimensions. Due to a poor prediction capability of the first model, a modified model was proposed and a better performance has been proved to reveal a closer description of processed surface quality. Also a deflection length has been verified using a different analytical approach.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1237-1239
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• 2005

In this study, we estimate the thermal conductivity of stainless steel reinforced Bi-2223/Ag tape which was made from American Superconductor. The equipments for thermal conductivity measurement was set up using conduction cooled cryocooler. Two direction of thermal conductivity was measured. The one is the direction of cut length, and the other is direction of transverse of wounded coil with insulation material. It was observed that the thermal conductivity of transverse direction of coil was extremely lower than that of cut length direction. It was mainly seems that superconducting filaments and insulation material were effected on thermal conductivity in thermal conductivity of transverse direction.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.344-355
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• 2012

This study was conducted to analyze on the operational time and productivities of logging operations in whole-tree logging operation system by tower-yarder and swing-yarder, and in cut-to-length logging operation system by excavator with grapple in order to establish the efficient logging operation system and to spread logging operation technique. In the analysis of operational time, in case of whole-tree logging operation system, the felling time was 46.6 sec/cycle by chain saw, the yarding time was 480.6 sec/cycle by tower-yarder, the yarding time was 287.4 sec/cycle by swing-yarder and the bucking time was 155.14 sec/cycle by chain saw. In case of the cut-to-length logging operation system, the felling and bucking time was 225.65 sec/cycle by chain saw, the cut-to-length extraction time was 4,972 sec/cycle by excavator with grapple, the branches and leaves extraction time was 3,143 sec/cycle by excavator with grapple. The forwarding time was 4,688 sec/cycle by wheel type mini-forwarder, the forwarding time was 2,118 sec/cycle by excavator with grapple and small forwarding vehicle. In the analysis of operational productivities, in case of whole-tree logging operation system, the average felling performance was $57.89m^3/day$ by chain saw, the average yarding performance was $20.3m^3/day$ by tower-yarder, $31.55m^3/day$ by swing-yarder respectively, the average bucking performance was $20.3m^3/day$ by chain saw. In case of the cut-to-length logging operation system, the average felling and bucking performance was $11.96m^3/day$ by chain saw, the average cut-to-length extraction performance was $34.75m^3/day$ by excavator with grapple, the average branches and leaves extraction performance was $37.66m^3/day$ by excavator with grapple, the average length of operation road construction was 73.8 m/day by excavator with grapple. The average forwarding performance by wheel type mini-forwarder and the average forwarding performance by excavator with grapple and small forwarding vehicle was $15.73m^3/day$ and $65.03m^3/day$, respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.34-47
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• 2000

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high specific modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles , spindles of machine tools, motor base, bearing mount for tool up and manufacturing. The molded composite machine elements are not usually accurate enough for mechanical machine elements, which require turning drilling , cutting and grinding. The experiment are surface grinding wheel GC60 to the carbon fiber epoxy composite specimen with respect to staking angle [0]nT , [45]nT, [90]nT on the CNC grinding machine. In this paper, the surface grinding characteristics of composite plate, which are surveyed experimentally and analytically with respect to the grinding force, surface roughness and wheel loading according to the variable depth of cut, wheel velocity and table feed rate are investigated.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.51-56
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• 2001

This study was carried out to research the effect of nutrient composition and GA4＋7 on growth, flower quality and bulb development in special hydroponics of cut tulip. Flowering of 'Cassini' was markedly accelerated by standard+GA4＋7, K200＋GA4＋7, N250＋GA4＋7 treatment, last internode was increased by N250 as compared with other treatment. For 'Christmas Marvel', flowering was promoted by K250＋GA4＋7, last infernode and total length were also increased with K250＋GA4＋7 as compared to other treatment. For 'Golden Apeldoorn', flowering was accelerated by K200＋GA4＋7, last internode was increased with N300＋GA4＋7 treatment and total length was increased in N250＋GA4＋7 treatment as compared with the standard plants. Bulb weight and number of 'Cassini', 'Christmas Marvel'and 'Golden Apeldoorn' were decreased by GA4＋7 as compared to non-treatment, and bulb diameter was not affected by GA4＋7.

• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.52-56
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• 2001

This study were looks at the effect of the initial cut length or stress concentration level, on the wave forms produced by crack propagation. The signals were collected, then classified visually for each type of sample. They were put into three classes according to their shapes in the time and frequency domain. Each class should domain signals which could be correlated to a certain micro-failure mechanism that occurs during the fatigue process. Classes of these signals compared, with each sample. To see if there were any classes common to the three samples. The fatigue test attempted to determine if the initial cut length has any influence on the type of signals.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.405-410
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• 2002

This paper deals with the flexural behavior of RC hems strengthened with CFRP plate and the estimation on anchorage length of CFRP Plate. Experimental variables included concrete strength, reinforcement ratio, cover thickness of concrete and length ratio of CFRP plate for a pure span. A failure load, failure mode, deflection and strain response at different distances from a cut-off point of CFRP plate were observed and anchorage length was determined through strain distribution of CFRP plate. Herein, anchorage length is defined the length between CFRP plate end and the beginning point of full composite behavior. Also, the anchorage length observed from the experiment was compared with Nguyen's equation and BS specification.