• Current Photovoltaic Research
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• v.4 no.4
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• pp.140-144
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• 2016

In this paper, core-shell structure of nickel/gold (Ni/Au) conductive layer on poly-methyl-methacrylate (PMMA) micro-ball was fabricated and its conduction property was investigated. Firstly, PMMA micro-ball was synthesized by using dispersion polymerization method. Size of the ball was $2.8{\mu}m$ within ${\pm}7%$ deviation, and appropriate elastic deformation of the PMMA micro-ball ranging from 31 to 39% was achieved under 3 kg pressure. Also, 200 nm thick Ni/Au conductive layer was fabricated on the PMMA micro-ball by uniformly depositing with electroless-plating. Adhesion of the conductive layer was optimized with help of surface pre-treatment, and the layer adhered without peeling-off despite of thermal expansion by collision with accelerated electrons. Composite paste containing core-shell structured particles well cured at low temperature of $130^{\circ}C$ while pressing the test chip onto the substrate to make electrical contact, and electrical resistance of the conductive layer showed stable behavior of about $6.0{\Omega}$. Thus, it was known that core-shell structured particle of the Ni/Au conductive layer on PMMA micro-ball was feasible to flexible electronics.

• Korean Management Science Review
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• v.33 no.2
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• pp.29-47
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• 2016

Trust is formed from the day-to-day and persistent interaction relationship. The trust demands more and more at the age of uncertainty. Human beings are using media interaction. The area of communication with media is extended to virtual space. The purpose of this study is to qualitatively explain trust building process in virtual team by media using. In the pursuit of this purpose, we executed in-depth interview with the person who have experience communicating by media with a man of a complete stranger. They experienced the trust building process. Interview data were analyzed by a Structured Coding Techniques. The derived seven categories were reconstructed in consideration of the cause-and-effect relationship and the flow of events. We have discovered a new trust model that was the result from communication by a media using. The model presented is very useful to Individuals who need a new trust building relationship with stranger or virtual team member.

• Fisheries and Aquatic Sciences
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• v.23 no.9
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• pp.25.1-25.9
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• 2020

Fish is an extremely perishable food product which requires proper handling soon after harvest. The present study was aimed at assessing post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia. Structured and semi-structured questionnaires were used to collect data on post-harvest fish losses and preservation practices from aquaculture producers, artisanal, and commercial fishers. All the fishers who landed on the lakeshore were interviewed, while aquaculture producers were randomly selected based on the information provided by the local department of fisheries. The results of the study revealed that all the fishers experienced post-harvest fish losses at varying degrees with those losing up to 10% of the total catch being in the majority. In contrast, aquaculture producers did not report any post-harvest fish losses. Most aquaculture producers commonly used chilling as preservation practice contrary to artisanal and commercial fishers who commonly used smoking and sun sun-drying respectively. Furthermore, fish product safety and quality control were poorly practiced in the district. Lack of cold storage facilities and fluctuating weather conditions were the major challenges impacting fish post-harvest activities. Therefore, to curb the loss of revenue due to post-harvest fish losses, we propose the introduction of new technology, self-development skills for fishing communities, and enhanced access to refrigeration facilities.

• International Journal of Contents
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• v.15 no.4
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• pp.113-119
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• 2019

It has been reported that large amounts of information on agri-foods were delivered to consumers through television and social networks, and the information may influence consumers' behavior. The purpose of this paper was first to analyze relations of social network service and broadcasting program on paprika consumption in the aspect of amounts to purchase and identify potential factors that can promote paprika consumption; second, to develop prediction models of paprika consumption by using structured and unstructured big data. By using data 2010-2017, cross-correlation and time-series prediction algorithms (autoregressive exogenous model and vector error correction model), statistically significant correlations between paprika consumption and television programs/shows and blogs mentioning paprika and diet were identified with lagged times. When paprika and diet related data were added for prediction, these data improved the model predictability. This is the first report to predict paprika consumption by using structured and unstructured data.

• Journal of the Korean Society of Combustion
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• v.11 no.2
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• pp.7-14
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• 2006

Catalytic combustion is one of the suitable methods for micro power source due to high energy density and it can be applied to micro structured chamber without consideration of quenching since it is flameless combustion. Catalyst loading in the micro structured combustion chamber is one of the most important issues in the development of micro catalytic combustors. In this research, to coat catalyst on the chamber wall, two methods were investigated. First, $Al_2O_3$ was selected as a support of Pt and $Pt/Al_2O_3$ was synthesized through the alumina sol-gel procedure. To improve the coating thickness and adhesion between catalyst and substrate, heat resistant and water solvable organic-inorganic hybrid binder was used. Porous silicon was also investigated as a catalyst support for platinum. Through the parametric studies of current density and etching time, fabrication process of $1{\sim}2{\mu}m$ of diameter and about $25{\mu}m$ depth pores was confirmed. Coated substrates were test in the micro channel combustor which was fabricated by the wet etching and machining of SUS 304. Using $Pt/Al_2O_3$ coated substrate and Pt coated porous silicon substrate, conversion rate of fuel was over 95 % for $H_2/Air$ premixed gas.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.52-57
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• 2010

The analysis of a crack in a bone-like material is performed numerically. The bone-like material is hierarchically structured and each hierarchy is structured by mineral platelets and protein matrix through staggered arrangement. Mechanical behavior of the composite can be analyzed using tension shear chain model. The Dugdale model is adopted to evaluate the fracture energy of Bone-like material. The fracture energy dissipation is assumed to concentrate within a strip near the crack tip along the prospective crack path. Fracture criterion of the bone-like material is estimated by using J integral. Effects of hierarchical level, ratio of elastic modulus of mineral to protein, aspect ratio of mineral platelet and volume fraction on J integral are investigated. It is found that the J integral decreases as elastic modulus ratio and hierarchy level increase. It is also shown that the J integral increases as the volume fraction and aspect ratio decrease.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.5
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• pp.1-9
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• 2006

The purpose of this study is to make a design guideline in designing constructed wetland which can treat water quality both of point and nonpoint source water pollution. It focuses on structural aspects of two case studies of constructed wetland applying SSB(Sustainable Structured wetland Biotope) system in Korea. The constructed wetland of Lake Ju-am which was constructed in 2002 by Environmental Management Corporation, was designed by applying SSB system. It shows higher removal efficiency than expected - 56% of BOD removal efficiency, 60% of T-N removal, and 76% of T-P removal efficiency. In two cases, total wetland areal extents were calculated referred to treatment efficiency. The system is consist of micro-cell structures : inflow channel, forebay, multiple wetland cells and micro-pool. When designing constructed wetland appropriate in local area, the total organic system of vertical and horizontal structure : geology, hydrology, land use, and ecological surroundings of the sites should be considered totally.

• Communications for Statistical Applications and Methods
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• v.19 no.2
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• pp.293-301
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• 2012

Quantile regression proposed by Koenker and Bassett (1978) is a statistical technique that estimates conditional quantiles. The advantage of using quantile regression is the robustness in response to large outliers compared to ordinary least squares(OLS) regression. A regression tree approach has been applied to OLS problems to fit flexible models. Loh (2002) proposed the GUIDE algorithm that has a negligible selection bias and relatively low computational cost. Quantile regression can be regarded as an analogue of OLS, therefore it can also be applied to GUIDE regression tree method. Chaudhuri and Loh (2002) proposed a nonparametric quantile regression method that blends key features of piecewise polynomial quantile regression and tree-structured regression based on adaptive recursive partitioning. Lee and Lee (2006) investigated wage determinants in the Korean labor market using the Korean Labor and Income Panel Study(KLIPS). Following Lee and Lee, we fit three kinds of quantile regression tree models to KLIPS data with respect to the quantiles, 0.05, 0.2, 0.5, 0.8, and 0.95. Among the three models, multiple linear piecewise quantile regression model forms the shortest tree structure, while the piecewise constant quantile regression model has a deeper tree structure with more terminal nodes in general. Age, gender, marriage status, and education seem to be the determinants of the wage level throughout the quantiles; in addition, education experience appears as the important determinant of the wage level in the highly paid group.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.176-183
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• 2003

The paper presents a feature recognition and segmentation method for surface approximation in reverse engineering. Efficient digitizing plays an important role in constructing a computational surface model from a physical part-surface without its CAD model on hand. Depending on its measuring source (e.g., touch probe or structured light), each digitizing method has its own strengths and weaknesses in terms of speed and accuracy. The final goal of the research focuses on an integration of two different digitizing methods: measuring by the structured light and that by the touch probe. Gathering bulk of digitized points (j.e., cloud-of-points) by use of a laser scanning system, we construct a coarse surface model directly from the cloud-of-points, followed by the segmentation process where we utilize the z-map filleting & differencing to trace out feature boundary curves. The feature boundary curves and the approximate surface model could be inputs to further digitizing by a scanning touch probe. Finally, more accurate measuring points within the boundary curves can be obtained to construct a finer surface model.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.71-79
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• 2006

The GNUnet proposed a file encoding method by lKB block size to support anonymity of files and decentralizes encoded block to peers through unstructured model. but, the encoding and block decentralizing method with 600$\sim$700MB large multimedia file appeared two problems. First problem. it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructured model added network load by broadcasting decentralizing method. This paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation to 1% and network load by proposal structured model sending answer through dedicated peer to decentralize block.