• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.350-353
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• 2001

This study proposes a new method for the transmission system expansion planning using the fuzzy integer programming. It presents stepwise cost characteristics analysis which is a practical condition of an actual systems. A branch and bound method which includes the network flow method and the maximum flow-minimum cut set theorem has been used in order to proceed the stepwise cost characteristics analysis. Uncertainties of the permission of the construction cost and not strict reserve rate and load forecasting of expansion planning have been included and also processed using fuzzy set theory in this study. In order to proceed the latter analysis, the solving procedure is illustrated in detail by branch and bound method which includes the network flow method and maximum flow-minimum cut set theorem. Finally, case studies on 21-bus test system show that the algorithm proposed is efficiently applicable to the practical expansion planning of transmission systems in future.

• 대한공업교육학회지
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• v.31 no.2
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• pp.350-363
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• 2006

Recently, the micro end-milling processing is demanded the high-precise technique with good surface roughness and rapid time in milli-structure parts, micro machine parts and molding industry. The cutting conditions of micro end-milling has an effect on surface roughness of cutting surface. Therefore this study was carried out to cut stainless steel using high revolution air bearing spindle and micro end-mill and analyze the cutting condition to get the optimum surface roughness by design of experiment. From this study, surface roughness have an much effect according to priority on depth of cut, revolution of spindle and feed.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.8-18
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• 1998

This study was to make a effective seed mixture types with Korean native plants by researching te seed timing of suitable woody plants and competitive germination results of various plants for the purpose of cut-slotes revegetation. The results are summarized as follows. 1. In field polystand experiment, comparative among severalcomposition combination for early coverage shows good condition. 2. In combination for early-coverage, mixture of native woody plants only seeded in May and June shows over 90% coverage. It was not inferior to the other mixture types. So mixture of Albizzia Julibrissin, Cymbopogon doeringii, Alnus hirsuta and Indigfera pseudo-tinctoria is able to use to mixture type. 3.In case of combination for scenic beauty, Rhus chinensis shows low germination in the mixture for scenic beauty. But 90 days after seeded in May, it recorded maximum 44 cm height, seeded in June recorede 18 cm height. 4. Lespedeza crytobotrya shows good elongation in the combination for early coverage and scenic beauty, but that effects on elongation of other plants. So, it demands close investigation about suitable mixing rate of plants. 5. Alnus hirsuta, Pinus thunbergii, Betula platyphylla, Spiraea prunifolia var. simpliciflora have been rarely germinated. So, the mixture of these plants wasn't adequate to use for revegatation.

• FLOWER RESEARCH JOURNAL
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• v.17 no.3
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• pp.185-189
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• 2009

This study was carried out to investigate the effect of shading (50% or not) and pruning height (3cm, 6cm, and 9cm) of remained above-ground plant part on shoot emergence aspect, mortality rate, flowering and cut flower characteristics of two years old Gypsophila paniculata plants. Days to shoot emergence (80%) advanced, emerged shoot number increased and mortality rate surveyed on late October decreased in 50% shading treatment. In addition to, mortality rate decreased, as above-ground plant part was highly pruned. Blooming was earlier with highly pruning the remained above-ground pan and under non-shading condition than shading. Growth traits such flower stalk length, primary branches number, stem diameter, and cut flower yield were the best and also non-particulate rate and rosette formation rate were the lowest in pruning height of 9cm under non-shading condition.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.762-764
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• 1999

This experiment was conducted to investigate the effect of pretreatments and storage conditions on quality and vase life of cut 'Red Sandra' rose (Rosa hybrida L.). 'Red Sandra' rose flowers were harvested and pulsed with distilled water, 0.2% RVB or 200ppm aluminum sulfate+3% sucrose+50ppm $AgNO_3$+0.1mM ethionine for 22 hours and then stored in wet or dry condition for 12, 24, 48 hours at low or room temperature. Pulsing with aluminum sulfate+sucrose+$AgNO_3$+ethionine delayed bent-neck, increased solution absorption and flower diameter, and prolonged vase life rather than pulsing with distilled water or RVB. Storage in wet condition or low temperature also delayed bent-neck, increased solution absorption and flower diameter, and prolonged vase life compared with storage in dry or room temperature condition. As the storage hours prolonged, solution absorption, flower diameter, and vase life were decreased especially pulsing with distilled water. Pulsing with aluminum sulfate+sucrose+$AgNO_3$+ethionine prolonged vase life compared to pulsing with distilled water or RVB regardless of storage conditions and shipping hours.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.47-54
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• 2003

Research during the past several years has established the effectiveness of acoustic emission (AE)-based sensing methodologies for machine condition analysis and process. AE has been proposed and evaluated for a variety of sensing tasks as well as for use as a technique for quantitative studies of manufacturing process. STD11 has been known as difficult-to-cut materials. The micro-grooving machine was developed for this study and the experiments were performed using CBN blade for machining STD11. Evaluating the machining conditions, frequency spectrum analysis of acoustic emission (AE) signals according to each conditions were applied. Fuzzy clustering method for associating the preprocessor outputs with the appropriate decisions was followed by frequency spectrum analysis. FFT is used to decompose AE signal into different frequency bands in time domain, the root mean square (RMS) values extracted from the decomposed signal of each frequency band were used as features.

• Journal of the Korean institute of surface engineering
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• v.29 no.1
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• pp.60-72
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• 1996

A photoetching process is widely used for small and high precision parts in machinery, electronic and semi-conductor industries. One of the high precision parts, grid is very important part of digitron which use electron display, and it is fabricated by only photoetching process because of high precision. In this study, to develop high precision digitron grid, characteristics of etching solution were investigated with electrochemical test, that was potentiodynamic test and immersion test in the ferric chloride solution and added some additives. Based on the electrochemical etching test, grid was fabricated by continuous photoetching process at various etching condition. From the result of measured line width and etching depth under-cut and etching factor were calculated. For the fabrication of 25$\mu\textrm{m}$ line width, optimal etching condition was etching temperature 40~$45^{\circ}C$, spray pressure 1.5kg/$\textrm{cm}^2$ and etching time 3~4min.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.466-471
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• 2003

The characteristics of a rock joint which influence the stability of rock mass structures, such as the cut slopes and the tunnels, are largely controlled by the conditions of the rock joint as well as its boundary conditions. Boundary conditions can be represented by assuming that the deformability(or stiffness) of the rock mass surrounding the joints is modelled by a spring with stiffness. A new direct shear apparatus is developed in this study, which adapts a servo control system using PID algorithm. This apparatus can be used to investigate the various aspects of shear characteristics of the rock joints at conditions of constant normal stress and constant normal stiffness and so on. It is possible that the behavior under the constant normal stiffness condition can be predicted by the normalized graphic method with results obtained from the tests in the constant normal stress condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.29-34
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• 2012

This study describes the selection of optimum machining conditions for a high-hardness resin by using a large 5-axis machine. The experiments were conducted to examine the main factors that affect the surface roughness, such as the spindle speed, axial and radial depths of the cut, and pattern of the cutter path. To analyze the experiment results, the factor with the biggest impact on machining was determined using the smaller-the-better characteristic of the Taguchi method; the effectiveness of the experiment was then confirmed by verifying the selected optimum machining condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1018-1021
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• 1997

This paper presents a result of simulation and improvement of grinding process for linear motion guide blocks. A simulation software, which is based on cylindrical grinding process. is used to predict the grinding wheel wear during the grinding process. To validate the simulation, the simulation result is compared with the experimental one. Simulation study is extended to obtain an optimal grinding condition for minimizing the grinding wheel wear. The optimal condition is validated through an experiment.