• Management Science and Financial Engineering
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• v.3 no.1
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• pp.1-14
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• 1997

We address the problem of determining the sequence of a vehicle with fixed capacity to visit n nodes at which a predetermined amount is picked up and/or delivered. The objective is to minimize the total travel distance of the vehicle, while satisfying the pick-up/delivery requirements and feasibility at all nodes. Existing methods for the problem allows the vehicle to visit a node twice, which is impractical in many real situations. We propose a heuristic algorithm, in which every node is visited exactly once. Computational results using random problems indicate that the proposed heuristic outperforms existing methods for practical range of the number of nodes in reasonable computation time.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.306-315
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• 1995

This paper presents a bin picking method using a slit beam laser in which a robot recognizes all of the unoccluded objects from the top of jumbled objects, and picks them up one by one. Once those unoccluded objects are removed, newly developed unoccluded objects underneath are recognized and the same process is continued until the bin gets empty. To recognize unoccluded objects, a new algorithm to link edges on slices which are generated by the orthogonally mounted laser on the xy table is proposed. The edges on slices are partitioned and classified using convex and concave function with a distance parameter. The edge types on the neighborhood slices are compared, then the hamming distances among identical kinds of edges are extracted as the features of fuzzy membership function. The sugeno fuzzy integration about features is used to determine linked edges. Finally, the pick-up sequence based on MaxMin theory is determined to cause minimal disturbance to the pile. This proposed method may provide a solution to the automation of part handling in manufacturing environments such as in punch press operation or part assembly.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.416-421
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• 2001

The subway station platform is designed in high platform for quick getting in/out which is against ordinary train platform. Out of 370 Metropolitan subway station platforms, subway stations which have cured platform are about 38％. In these cases, as the distance between subway and platform would become longer, handicapped people's wheelchairs, baby carriers and old and feeble people can feel uncomfortable when they are getting in and out Also, passengers often fall into track because of the height difference between high platform and track. And if passengers go down on track to pick up something fallen, they sometime fail to climb up and happen to hit against subway. To solve out these kind of inconveniences and prevent accidents, we have developed subway station high platform safety system and finished tests. This safety system is consisted of safety block, screened door and safety wall. This study explained the composition and function of this system and presented the test result to identify its performance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.80-94
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• 1994

As for axisymmetirc sheet metal forming, a kind of pick-up apparatus for body-wrinkling is deviced. Experiments with both hemispherical and flat headed punches, with various clearances between punch and die, with respect to three kinds of materials each of which has two thicknesses, are performed. Firstly the process of evolution of body-wrinkling is observed. Then the critical blank-holding force (or meridional tensile force) for suppression of body-wrinkling at a specified punch-stroke is measured for all cases mentioned above. An empirical formula for it is proposed. Deformation patterns and stress distributions are analysed by the use of FEM. A simplified critical condition for body-wrinkling is formulated and introduced into the FEM program. And its effectiveness is checked by comparison with the experimental results. Using this FEM system, the governing factors of body-wrinkling are cleared up.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.117-124
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• 2005

This study developes the vibration model to estimate the vibration energy of compact disc player's mainbase assembly which is supported by dampers and springs, and this model is verified by experiment. From frequency response function, we investigate the natural frequency and mode shape in the up/down direction for mainbase assembly. In order to determine the analysis frequency band, we investigate the excitation frequency of road from the vehicle test. As the characteristics of dampers and springs are changed, we carry out the sensitivity analysis of vibration energy for mainbase assembly which include optical pick-up and feeding system. And we found out that the properties of damper were dominant element in the vibration energy of mainbase assembly's CG(center of gravity).

• Research in Community and Public Health Nursing
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• v.8 no.1
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• pp.144-154
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• 1997

This study is planned to gather necessary data for setting up a system on students' health care in the university. In order to obtain statistical data on the students' health care problems especially in 'depression' among the mental health problems of the students, 'The Beck Depression Inventory' by A. T. Beck and 'Zung's Self-Rating Depression Scale' by W. W. K. Zung were used for gathering numerical data of scale of depression. It is evident that we have to prepare for further medical examination and health care educations for several students. For these students, it is clear that they have problems not only in mental health but also in physical health. I have screened out the high scored students for comparison and analysis. And it disclosed that we have to build up a periodical and continuous 'Health Screening System' utilizing Health Questionnaire for both physical and mental aspects, which will bring up us the very exact result to pick out any person who has healthy problem among the enormous number of the students with handy, convenient and effective procedures but with the least expense and effort. Also it is my firm confidence that this system will be applicable for primary health care control of mass population in local community or any organization.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.107-112
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• 2020

Recently, the atomically thin transition-metal dichalcogenide (TMD) semiconductors have attracted much attention owing to their remarkable properties such as tunable bandgap with high carrier mobility, flexibility, transparency, etc. However, because these TMD materials have a significant drawback that they are easily degraded in an ambient environment, various attempts have been made to improve chemical stability. In this research article, I report a method to improve the air stability of WSe₂ one of the TMD materials via surface passivation with an h-BN insulator, and its application to field-effect transistors (FETs). With a modified hot pick-up transfer technique, a vertical heterostructure of h-BN/WSe₂ was successfully made, and then the structure was used to fabricate the top-gate bottom-contact FETs. The fabricated WSe₂-based FET exhibited not only excellent air stability, but also high hole mobility of 150 ㎠/Vs at room temperature, on/off current ratios up to 3×10⁶, and 192 mV/decade of subthreshold swing.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.281-287
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• 2016

Purpose: The purpose of this study is to develop a walking-type two-row sesame reaper, which can simultaneously perform the cutting and collecting of sesame plants and other crops like perilla and soybean. Methods: The factors involved in reaping sesame were determined experimentally in order to design a prototype of the sesame reaper. The prototype is made up of four parts for cutting, conveying, collecting, and running. The height of two disc-plate saw blades on the cutting part is adjusted by an adjusting wheel, and peripheral speed is adjusted in accordance with the running speed. The conveying belt of the conveying part can be tilted from $0^{\circ}$ to $90^{\circ}$. The collecting part extracts a predetermined amount of transferred sesame plants. The prototype was used to evaluate the performance at different working speeds, so that the work efficiency can be calculated. Results: The center of gravity of the sesame plants was 900 mm, measured from the end of the cut stem. The diameter of the disc-plate saw blade was determined to be 355 mm, peripheral speed was 20.4-32.7 m/s, and the picking height of the conveying belt for sesame was 130 mm. The performance of transfer and collection of the sesame, when the insertion angles were $60^{\circ}$ and $90^{\circ}$, proved to be excellent. However, when the angle was over $120^{\circ}$, the performance was only 75-80%. The performance was at 100% efficiency when the ratio between running speed and conveying belt speed of the prototype was 1:2, which seems to be the ideal ratio for the sesame reaper. Conclusions: A sesame reaper was developed, which can integrate the processes of cutting, conveying, and collecting, by investigating and considering various factors involved in the reaping process. The sesame reaper can reduce the costs for yielding and producing sesame due to its highly efficient performance.

• Journal of Sericultural and Entomological Science
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• v.27 no.2
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• pp.47-53
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• 1985

The studies on the reaction of Urea-Formaldehyde(UF) resin with silk fabric were studied, and the final results summarized as below; 1. The pH and UF molar ratio for preparing liquid resin was found at pH 4-5 and UF molar ration 1:2 and above. 2. The weight gains were increased with respect to increase in concentration of UF resin solution, while moisture regains were decreased. 3. The weight gains were significant high in case of wet pick up 70%. 4. The weight gains were increased with respect to increase in curing temperature and the amount of catalyst((NH4)2SO4) found was 2.5% on the weight of Dimethylol urea and Hydrochloric acid was 1%, Tartaric acid was 10%. 5. The effect of different catalyst on wash fastness of UF resin was good where as in case of acidic catalyst was significantly high. 6. The weight gains with different catalyst was high where as in case of potential acid catalyst was significantly high. 7. The crease recovery are increased with the increase of the weight gain of silk fabric and also stiffness are increased.

• Textile Coloration and Finishing
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• v.10 no.4
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• pp.37-44
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• 1998

The purpose of this study was to elucidate the effect of weight loss of polyethylene terephthalate(PET) fabrics on the mechanical properties such as bending and shear. In order to compare the effect of treatment machine on the mechanical properies of treated PET fabrics, PET fabrics were hydrolyzed with NaOH aqueous solution using Tank machine and Liquor flow machine, respectively. The results were as follows ： 1. The bending rigidity and shear stiffness of hydrolyzed PET fabric decreased markedly up to about 10％ weight loss regardless of treatment machines. At the above 10％ weight loss, the variation of these properties is nearly unchanged. In addition, the bending hysteresis and shear hysteresis also showed similar trend. 2. Weft density change of PET fabrics treated with Liquor flow machine decreased by 1pick/inch. It is assumed that this is attributed to the tension during the treatment of Liquor flow machine. On the other hand, the weft density change of PET fabrics treated with Tank machine is scarcely influeneced by the weight loss. While warp density of PET fabrics treated with Liquor flow machine had no change with weight loss, warp density of PET fabrics treated with Tank machine decreased by 6pick/inch due to the tension. 3. The bending rigidity and shear stiffness of PET fabrics hydrolyzed with liquor flow machine slightly higher than with Tank m/c at the above 10％ weight loss. It is assumed that this is caused by the increasement of the crossing pressure of warp and weft yarn and contact points of filaments in the yarns. Also, the bending and shear hysteresis of PET fabrics treated with Tank machine were higher than that of liquor flow machine.