• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.3
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• pp.172-177
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• 2014

Industrial, medical, environment and agriculture application of pulse power technology have been developing rapidly in many field. In order to make use in the form of pulses is applied to the pulse forming technique. At this time, spark gap is generally used for the pulse forming. Spark gap may be possible to simulate the shape of the electrode, to know the uniform or non-uniform electric field of the electrode structure. Further, it can be determined using Paschen's law applied pressure of the insulating gas in accordance with the voltage which is created using the value of the electric field. In this paper, we tried to found using a formula and the simulation process to determine the pressure. The value of the electric field is different according to the shape of the electrode. So, the range of pressure applied also varies. In order to withstand the 100 kV with a gap of 5 mm, the nitrogen gas must be applied to about 7 bar in the electrode structure. On the other hand, in the same conditions, Sulfur hexafluoride gas must be applied to about 2 bar. Consequently, the Sulfur hexafluoride gas has a higher insulation properties than nitrogen gas may be applied to low pressure at the same conditions.

• Corrosion Science and Technology
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• v.6 no.5
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• pp.257-260
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• 2007

In order to further improve the corrosion resistance and wear resistance of the Ni-P coatings of electroless plating, electroless Ni-P/n-$Al_2O_3$ composite deposits were prepared by adding some nano $Al_2O_3$ Particles in Ni-P plating bath. The bath composition and proproties were studied in this paper. The orthogonal test was applied in order to get the new composite solution, taking the initial stable potential as evaluation standard and considering the elements correlation at the same time. The processing parameters have been optimized by single factor experiment in which the depositing speed was chosen as the evaluation standard. The results showed that the process is stable and the composite Ni-P/n-$Al_2O_3$ deposits werebright and smooth, whose hardness and corrosion resistance are much better than simple Ni-P coatings. Furthermore the surface appearance and structure of the composite Ni-P/n-$Al_2O_3$ coating were investigated by SEM and XRD method. It was proved that the coating surface is typical cystiform cells and its structure is amorphous. All test results ofcomposite coating showed that all various physical coating properties had been improved by adding nano-particles. The hardness of optimal coating is more than 600HV and increases to 1000HV after heat-treating, and its hardness is 20~50% higher than Ni-P coating. The rust points appeared in 200 hour by immersing the coating into the 10%HCl solution and the corrosive speed is $3{\times}10^{-3}mg/(cm^2{\cdot}h)$which was obtained after 300 hour. In the same condition Ni-P coating is $5.6{\times}10^{-3}mg/(cm^2{\cdot}h)$. The salt spray resistance of the layers can exceed 600h with the thickness $20{\mu}m$.

• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.416-421
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• 2007

Physical damage to fruits and vegetables caused by shock degrades the value of product in the fresh market. In order to design a product/packaging system to protect the product, the G-factor to the product that causes shock damage needs to be determined. The shock fragility of organisms such as fruits with a concept correspondent to the G-factor of industrial products was calculated and we defined the allowable bio-shock fragility index as the value divided peak acceleration that was generated in safe drop height by standard acceleration of gravity. We did modeling for safe drop hight that would prevent fruits from damage by drop tests and tried to estimate the allowable bio-shock fragility index of pears and apples for optimum packaging design. The bio-shock fragility index of pears was in the range of $0.74{\sim}2.29\;G$, while apples had a slightly higher value than that of pears, of $0.51{\sim}2.98\;G$. This result shows accordance with the general fact that apples have a firmer structure and get less damage from the same impact. Based on this result, it is possible to create an optimum packaging design by providing a damage standard by impact.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.68-111
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• 1998

The structure of the Hanwoo (Korean Native Cattle) Industry remains very weak and vulnerable to the WTO/IMF system. Considering that the majority of cattle farmers are small sized, and that marketing systems are outdated and inefficient, rapid expansion of lower priced beef imports by WTO system and rapid increasing of production costs by IMF system would lead to the deprivation of a regular source of farm income and threaten the stability of rural life. Accordingly, the Hanwoo industry should be expanded in accordance with progress in the implementation of (1) programs for the structural adjustment and (2) measures to compensate for the loss. Efforts for lowering major production factor costs needs to continue, In order to increase the supply of calves at low cost, the programs of collective cow-calf farms should be expanded, thereby reducing the cost of calf purchase, which constitutes the largest share of Hanwoo production cost. Also, feedlot operations should be encouraged for small herd farms in order to achieve a substantial saving in beef production costs by integrated operations from calf production to cattle fattening. A substantial saving would also be made by collective purchase and distribution of various inputs through the cooperatives' channels. Extension services should be strengthened for cattle farm management, cattle care and feeding, prevention of cattle disease, etc. In order to minimize cash outlays for commercial mixed feeds, utilization of far by-products as feeds should be enhanced and production of forage crops productive of resources, such as land and rural labor, during the farm o(f-season, needs to be encouraged. Also, technological development for enhancing the nutritional value of farm by-products should be encouraged. Measures for successful segregation of the Hanwoo beef market should be implemented, thereby enhancing incentive for quality beef producers and protecting consumers willing to pay higher price for quality beef. For development of the Hanwoo industry, a considerable time frame would be required in order for (1) small livestock farmers to make a successful adjustment by staying in the enterprise and achieving increased price efficiency (2) livestock farmers to acquire know-how for producing quality Hanwoo beef, (3) the ongoing Government policy of enhancing price-quality competitiveness, and for improving the quality Hanwoo beef marketing to take root. (4) consumers to increase their ability to distinguish meat quality, and others.

• Steel and Composite Structures
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• v.34 no.1
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• pp.75-89
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• 2020

The current paper illustrates the effect of in-plane varying compressive force on critical buckling loads and buckling modes of sandwich composite laminated beam rested on elastic foundation. To generalize a proposed model, unified higher order shear deformation beam theories are exploited through analysis; those satisfy the parabolic variation of shear across the thickness. Therefore, there is no need for shear correction factor. Winkler and Pasternak elastic foundations are presented to consider the effect of any elastic medium surrounding beam structure. The Hamilton's principle is proposed to derive the equilibrium equations of unified sandwich composite laminated beams. Differential quadrature numerical method (DQNM) is used to discretize the differential equilibrium equations in spatial direction. After that, eigenvalue problem is solved to obtain the buckling loads and associated mode shapes. The proposed model is validated with previous published works and good matching is observed. The numerical results are carried out to show effects of axial load functions, lamination thicknesses, orthotropy and elastic foundation constants on the buckling loads and mode shapes of sandwich composite beam. This model is important in designing of aircrafts and ships when non-uniform compressive load and shear loading is dominated.

• Advances in concrete construction
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• v.13 no.2
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• pp.191-198
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• 2022

FIB is introduced as the sole guideline for the design purpose that results in a practical relationship for the torsional capacity of concrete beams strengthened with carbon fiber-reinforced polymer (CFRP). This study applies first-order reliability method to assess the reliability evaluation of the torsional capacity of CFRP-strengthened beams on the basis of FIB guidelines. In terms of steel reinforcement losses, this study applies a corrosion model to investigate the ceaseless deterioration of the existing structure. Hence, the average of reliability indices varies between 2.68 and 2.80, indicating the reliability viewpoint of the design methodologies. The average values are somehow low compared to the target values of reliability (3.0 or 3.5) applied in the calibration stage of the FIB guideline. In this way, the partial safety factors may change in the forthcoming guideline revisions. For this aim, the reliability of strengthening ratio was applied to assess the variation in the average value of the reliability index with different partial safety factors. The performance of parametric study for the factor proved that minimum values of 1.60 and 2.32 are required for target values of reliability (3.0 and 3.5), respectively.

• Informatization Policy
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• v.19 no.2
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• pp.57-84
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• 2012

If we observe the formation of communities of people and participation methods within them, we can see that those communities are developing more efficiently due to the penetration of smart phones and the growth of SNS. This trend also has an impact on information sharing activity between people and enables more active information sharing than ever before. But information sharing on SNS does not just involve the SNS users sharing information with each other. Important factors affecting the information sharing activities include the type of relationship between the users and the attitude of the information sharing individuals. Accordingly, this study selected perceived social support, perceived social influence, and perceived network structure as the factors that affect the continuous intention of people to use SNS, and performed a higher order factor analysis on those factors. Between continuous intention to use SNS and intention to share information, we selected relationship quality and information sharing behavior and executed a path analysis between the factors. We carried out an empirical analysis by utilizing SPSS 18.0 and SmartPLS 2.0 as analysis tools. Using these tools, we investigated the factors influencing continuous intention to use SNS, and tested the significance between the role and path of relationship quality and information sharing behavior between continuous intention to use SNS and intention to share information.

• Journal of the Korean Society for Library and Information Science
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• v.20
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• pp.163-222
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• 1991

This dissertation are studying the conceptual structure of decision making situation in libraries, by analyzing the library function, decision makings of library and then seeking economic and efficient alternative decision making by programming the· decision making situations, and finally, introducing how to apply management information system or decision making support system. For this purpose, in order to analyzing necessary factors for the decision making system, the questionnaire used Lickert method were distributed to 400 librarians of 36 universities in Seoul by means of mail. 193 librarians, $48\%$ of the questionnaire, are returned are studied by using 'SYSTAT' statistical software to figure out the factors of the decision making system. This dissertation was put six hypotheses and tested with the returned questionnaire. The following five result can be asserted. First, to the higher degree of the librarians' participation in the important library decision makings, the quality of formal library services are improved regardless of seniority of the work. Secondly, the t-test results show that all of t-test scores of seniority of the work, educational background, and responsibilities of the work are exceeding significant level and perception of decision making was proved to be different depending on seniority of the work, educational background, and responsibilities of the work in libraries. Thirdly, as the results of factor af factor analysis, the encouragement on participation in the library academic activities, the extent to get useful information about performances of library and the improvements of library works were grouped by similar posibilities of distribution and therfore the academic activities, the collection of information and the improvement of library performances is proved to be interrelational each other. Fourthly, the fifth hypothesis of the close relationship between the decision making situation and types of advisor by it was more or less interrelational, but their relationship was not seen some significancies. Lastly, as the dynamic organization of library management forming a special commitee or a project team with librarian can improve the extent and quality of the librarian's participation in the decision making of library works, and thus library will become to performance more rational and effective library management.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.84-92
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• 2009

Recently, lots of the research aspects of space, materials, structure, construction method relation to improving the flexibility going on throughout the construction industry, moreover the development of construction key technology has been accelerating by reason of deterioration in the apartment housing. Therefore, this study should firstly suggests assessment list of construction key technology through investigation of questionnaire and consultation of the expert on the basis of case studies, and should select it about the flexibility which making social issues lastly in the apartment housing. Secondly, this study should classify, reestablish core technology through inspection procedure of feasibility study among lists of deduced key technology. Finally, this study will suggest the manual & guideline for improving the flexibility for a long-life apartment housing at the next generation by selecting, analyzing and estimating higher score items of all key technology.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.1-9
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• 2005

The interaction between hypersonic free stream and side jet flow at high altitudes is investigated by using the direct simulation Monte Carlo (DSMC) method. In order to alleviate the difficulty associated with the large density difference between the free stream and the side jet flow and to simulate the two flows simultaneously, a weighting factor technique is applied. For validation, the corner flow over a pair of plates perpendicularly attached is calculated with and without a side jet, and the results are compared with experiment. For a more realistic configuration, the flow past a blunted cone cylinder shape is solved. The leeward or windward jet is injected into the free stream and the effect on the aerodynamic force and moment is observed at various flow angles. The lambda shock effect and the wake structure are studied in terms of the surface pressure differential. A higher interaction between the free stream and the side jet flow is observed when the side jet is injected in the windward direction.