• CDE review
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• v.4 no.3
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• pp.26-31
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• 1998

Recent trend of popularity of CAE(Computer Aided Engineering) tools and its availability, partly contributed by significant price reduction of H/W and SW, makes us believe CAE has already established terra firma as de jure tools, enablint the design improvement in the manufacturing am. However, if your jobs are required to be working closely with engineers located in the front line of manufacturing site, CAE is observed far from popularity, still being regarded as exclusive tools for engineers holding advanced degrees. Conventional methodologies depending on knowledge that was accumulated thorough trial and errors, depending primarily on engineering tables and formulas or proprietary know-how, are preferred as the de factor standard under the roof of contemporary development shops. Samsung camera, having stared its business since early 、80, has accumulated enough technological strength to compete in the world market. As today's consumers demand more sophisticated featured-lighter weight, built-in multi zoom and miniature size fitting in the palm-from camera manufacturer, so should Samsung camera respond to ever-delicate consumer's needs with great flexibility. Consequently conventional designers, without sophisticated analytical tools, with encounter solving the critical design factors that have never been treated as seriousness-marginal safety factors induced by reduced size of parts. In the study, CAE results of boss and gears were demonstrated as examples, which confirms the facts that the simple analysis done by front line designers, can bring distinguishable effects on the potential improvements of design and on the consequential influences on the future design process-simulation before actual tooling and productions.

• Journal of Technology Innovation
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• v.16 no.2
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• pp.41-63
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• 2008

Employing firm-level data during the period of 1980-2006, this paper analyzes the R&D efficiency of IT SMEs. We focus on comparing the R&D efficiency of IT SMEs with that of large-sized IT firms and non-IT SMEs. The results are summarized as follows. First, the R&D investment of IT SMEs has not been increased since 2000. In IT manufacturing industry, the portion of the R&D investment of IT SMEs is no more than 10.6% in 2005. Second, we analyze the innovation capacity of SMEs with the number of the patent application. The result is similar with the trend of R&D investment. The portion of the patent application of SMEs has not been increased since 2000. Third, the R&D efficiency of non-IT firms is higher than that of IT SMEs regardless of the firm size. The R&D efficiency of non-IT SMEs is over three times as large as that of IT SMEs. Meanwhile, The R&D efficiency of the large-sized non IT firms is 1.86 times as large as that of IT large-sized firms. Finally, we estimate the R&D elasticity and compare between IT manufacturing and service industry. The result shows that the R&D elasticity of IT service industry is higher than that of IT manufacturing industry, regardless of firm size.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.6
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• pp.687-695
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• 2015

An experimental study on the automation of the coffee roasting process was conducted. For this study, a temperature sensor, controllers, and motors were added to a manually operated coffee roaster. The temperature, time, and exhausting damper control were selected as the control parameters. The thermocouple measurements were severely influenced by the thermocouple size and location of the roaster. As a result, the standard thermocouple size and location of the roaster were experimentally set to show a similar trend of temperature change by using a previously installed thermometer. A standard roasting process was chosen through repeated roasting experiments and the advice of a roasting expert. The automation of the roasting process was successfully executed using temperature criteria, such as the bean input and first and second crack occurrence, and by controlling the exhausting damper opening time. The control parameters and roaster skills can be used for similar types of roasters for process automation.

• Korean Journal of Health Education and Promotion
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• v.31 no.1
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• pp.71-83
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• 2014

Objectives: This study examined the trend of alcohol-related research, with a specific focus on adolescent problem drinking, to provide evidence for prevention and intervention for adolescent alcohol problems and alcohol policy in Korea. Methods: A total of 17 studies examining adolescent problem drinking were included for meta-analysis. Using CMA (Comprehensive Meta-Analysis) 2.0, the effect sizes of correlation coefficients of variables related to adolescent problem drinking were analyzed. Results: 176 variables were extracted under 4 higher categories and 20 sub-categories. Variables were extracted using the four higher categories, namely individual, family, environmental, and demographics, as the theoretical framework. Results showed that most studies on adolescent problem drinking focused mostly on individual factors followed by family factors. Variables including drinking motivation, drinking expectancy, and peer relations showed relatively higher effect size. Conclusions: Study findings suggest the importance of balance between individual and environmental factors in examining problem drinking among adolescents. In order to provide evidence for alcohol policy, more attention should be given to macro environment that are known to influence adolescent drinking.

• Nuclear Engineering and Technology
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• v.17 no.2
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• pp.116-128
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• 1985

Considering vacancy generation and migration in grain and sink at grain boundary, a mechanistic densification model which is dependent on UO$_2$ temperature and microstructure has been developed. This densification model is a function of time, fission rate, temperature, density, pore size distribution and grain size. The resultant equation derived in this model which is different from Assmann and Stehle's resultant equations for four temperature regions, can be applied directly for all the pellet temperatures. The predictions of the present densification model very well agreed with the experimental data. This model well predicts absolute magnitude and trend in comparison with the empirical algorithm used in KFEDA code.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.852-857
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• 2014

This study was carried out to develop a simple, convenient, and reproducible testing device to determine wettability and dispersibility of dairy powders. The testing device consists of a sieve ($150{\mu}m$) attached to a sample chamber, sensors mounted on a supporting body and a main control unit containing a display panel. The sensors detect the difference in electrical resistance between air and water. A timer is automatically triggered by the sensor when the bottom of sample-loaded chamber contacts water in the petri dish. Wettability and dispersibility of commercial skim milk powders (SMPs) produced at different heating strengths (low-, medium-, and high-heat SMP) are compared using the new testing device. Wettability of the SMPs were correlated with particle size and are found to increase in the order of medium-, low-, and high-heat SMP regardless of the amount of sample tested. Dispersibility of SMPs showed the same trend and high heat-SMP which has the smallest particle size resulted in the lowest dispersibility. Unlike existing methods, the new testing device can determine both wettability and dispersibility of powders and successfully detected differences among the samples.

• Journal of The Korean Association For Science Education
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• v.10 no.1
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• pp.95-118
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• 1990

This students ideas in science are diverse and unique It is realized that children's preconceptions and misconceptions established before lessoning hgve a crucial in fluence on the following education. so it is meaningful to analyse the children's concept of temperature for the better teaching strategy in this study. This survey of the Elementary school children's concept is designed for the subtopics of temperature as the relation between heat and temperature, He relation between volume(size) and temperature, the temperature of change of state on water, the temperature of substances in the condition of thermal equilibrium. Using Clinical method, this research was executed to 306 children at elementary school. The network method or the analyse of questionnaires were used to analyse the children's response. Findings of this survey are as follow. Students are already familiar with such concept as this increase of temperature by geating, but they think every substance is not the case. Many students appears to believe that the temperature of an object(substance) is related to its size(vloume) Qualitative tasks are difficult than qualitative ones. This trend appear highly in the low grade students. Don't know the temperature of change of state on water and it's stability They think that the temperature is determined by the heating time(period) and the temperature of heating source. Students think, in general that temperature of substance in the condition of thermal equilibrium is different.

• Journal of the Korean Ceramic Society
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• v.56 no.5
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• pp.474-482
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• 2019

Chromium-doped zinc ferrite nanoparticles with the general formula Cr_yZnFe_2-yO₄ (y = 0, 0.025, 0.05, 0.075, and 0.1) were synthesized by a surfactant-assisted chemical co-precipitation route using metal nitrate salt precursors. The phase purity and structural parameters were determined by powder X-ray diffraction. The concentration of Cr³⁺ doped into ZnFe₂O₄ (ZF) noticeably affected the crystallite size, which was in the range of 22 nm to 36 nm, and all samples showed a single cubic spinel structure without any secondary phase or impurities. The lattice parameter, X-ray density, and skeletal density increased with an increase in the Cr-doping concentration; on the other hand, a decreasing trend was observed for the particle size and porosity. The influence of Cr³⁺ substitution on ZF magnetic properties were studied under an applied field of 15 kOe. The overall results revealed that the incorporation of a small amount of Cr dopant changed the structural, electrical, and magnetic properties of ZF.

• Journal of the Korean housing association
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• v.9 no.1
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• pp.11-19
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• 1998

A transitional trend of architectural elements which would happen naturally in a building may be a cue to the changes of the times. In this respect, this study is to investigate the transformation of types of windows and doors with the full-openable bay size in Korean Buddhist Temples and search for transitional process on types of windows and doors according to the flow of the times. As the results of this study, the following conclusion could be obtained. 1. The type of bunhap(connected door frame) Deul E-Yul-Gae doors + Deul E-Yul-Gas (life up) single windows would be changed from windows of a bay just beside a on the transition that the whole would be altered into the same type. 2. The type of Bunhap (connected door frame)Deul E-Yul-Gae doors + Bunhap (connected door frame) Deul E-Yul-Gae doors would be changed into Bunhap swinging doors that the whole of windows and doors could be opend very easily. 3. The type of Bunhap swinging doors + Bunhap swinging doors would be seen in the transition that windows and doors would be altered separately due to the exchange from window and doors of one of a middle bay or a bay just beside a middle bay to swinging doors and etc.

• Journal of Korea Foundry Society
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• v.19 no.5
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• pp.427-432
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• 1999

Most investment castings contain some porosities and microcavities. In this study, we investigated the elimination trends of various internal defects in IN738LC investment castings for industrial gas turbine blade by hot isostatic pressing. The results showed that cylindrical defects which are under $0.6mm{\Phi}{\times}7mm$ size are mostly eliminated and aspect ratio of defects is more sensitive factor than their cross section shape in removing these defects. Increasing hot isostatic pressure and holding time doesn't affect the elimination trend of cylindrical defects over $0.6mm{\Phi}{\times}7mm$ size because first step(plastic deformation) of HIP densification doesn't occur under these HIPping conditions.