• The KSFM Journal of Fluid Machinery
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• v.13 no.5
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• pp.43-53
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• 2010

This study investigates a design optimization of a rotating two-pass rectangular cooling channel with staggered arrays of pin-fins. The radial basis neural network method is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer with shear stress transport turbulent model. The ratio of the diameter to height of the pin-fins and the ratio of the streamwise spacing between the pin-fins to height of the pin-fin are selected as design variables. The optimization problem has been defined as a minimization of the objective function, which is defined as a linear combination of heat transfer related term and friction loss related term with a weighting factor. Results are presented for streamlines, velocity vector fields, and contours of Nusselt numbers, friction coefficients, and turbulent kinetic energy. These results show how fluid flow in a two-pass square cooling channel evolves a converted secondary flows due to Coriolis force, staggered arrays of pin-fins, and a $180^{\circ}$ turn region. These results describe how the fluid flow affects surface heat transfer. The Coriolis force induces heat transfer discrepancy between leading and trailing surfaces, having higher Nusselt number on the leading surface in the second pass while having lower Nusselt number on the trailing surface. Dean vortices generated in $180^{\circ}$ turn region augment heat transfer in the turning region and in the upstream region of the second pass. As the result of optimization, in comparison with the reference geometry, thermal performance of the optimum geometry shows the improvement by 30.5%. Through the optimization, the diameter of pin-fin increased by 14.9% and the streamwise distance between pin-fins increased by 32.1%. And, the value of objective function decreased by 18.1%.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2552-2557
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• 2007

Shape optimization of an internal cooling passage with staggered dimples on single surface is performed and performances of surrogates are evaluated in this paper. Optimizations are performed so that turbulent heat transfer can be enhanced compromising with pressure loss due to friction. The three-dimensional governing differential equations have been solved to find the overall Nusselt number and friction factor which are related to the objective functions of this problem. Three design variables were selected among the dimensionless geometric variables. Basic surrogate models such as second order polynomial response surface approximation (RSA), Kriging meta-modeling technique, radial basis neural network (RBNN), and derived press based averaged (PBA) surrogate model are constructed. The optimal points are searched from the above constructed surrogates by sequential quadratic programming (SQP). It is shown that use of multiple surrogates can increase the robustness in prediction of better design with minimum computational cost.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.1
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• pp.1-17
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• 1994

There are several gene transfer methods available to introduce foreign DNA into animal. The most common method at present is microinjection. However, the overall efficiency of producing practical application of gene transfer technology to livestock species is production of pharmaceuticals. Rare human proteins, which cannot be produced into milk of transgenic animals. Large amount of biologically active protein may be obtained from transgenic farm animals using this system. Growth-related application to livestock species using growth hormone genes or factor genes have been disappointing. There were many undesirable side effects noted in the transgenic animals. More sophisticated on or off transgene expression are needed to control expression of transgenes in the transgenic animals. Turning positive effects while circumventing potentially harmful effects.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.1
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• pp.121-130
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• 2016

There is a growing interest in the technology transfer and commercialization both at home and abroad. Accordingly, this study looked at the concept of technology transfer and commercialization, identified the factors that should be taken into account in order to facilitate technology transfer and commercialization, and then performed a empirical analysis. As for the conventional technology transfer and commercialization, there was a tendency to limit its scope to the exploration, transfer and commercialization of technology itself. Here in this research, technology transfer and commercialization is defined the category to expand as various activities implemented in order to make sure that intellectual properties such as intangible technological developments, know-how, and knowledge are transferred between the relevant parties through a contract or negotiation, and the party to which the transfer is made can then further develop and exploit the technology into tangible products and other activities to obtain economic benefit out of that. In addition, the findings of the positive analysis of technology transfer and commercialization revealed that the focus of facilitating technology transfer has been on the technology itself, its management and securing efficiency of the systems and institutions involved in the technology transfer and commercialization. So there was lack of recognition as to the importance of financial support given to the phase of technology commercialization. This indicates that when it comes to the technology transfer and commercialization, quantitative performance has been the focus of interest such as patent application, registration, number of technology transfers, royalty, etc. So there was not enough understanding as to the issues of starting up a business, creating quality jobs through technology transfer and commercialization, which are directly related to the realization of the creative economy. In this regard, this research is expected to be used for the development for the future policies to boost technology transfer and commercialization as it suggests not only simply ensuring quantitative performance but also necessary to create the environment for the creation of the stable ecosystem for the parties involved in the technology transfer and commercialization and then to build circumstances in which creative economy can be realized.

• Journal of Preventive Medicine and Public Health
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• v.34 no.1
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• pp.35-40
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• 2001

Objectives : To elucidate the transient effects on the risk of occupational injuries as acute events and establish so alternative proposal. Methods : The study population comprised a total of 302 workers randomly selected from applications for occupational injury compensation reported to the Inchon local labor office from January 1. 1999 to December 31. A case-crossover design, where each case serves its own control, was applied to this study. Through a telephone interview, workers provided useful data concerning five job related stressful events such as company transfer, work load change, overtime work, exchange duty, and work-part transfer. They were asked whether there were stressful events within a week of the occurrence of injury and the degree of stress. Exposure status from one year prior was used as control information. In the end, the data provided by 158 of selected persons was used for the analysis based on the quality of the data provided by the participants. A conditional logistic regression was used to discover the transient effects on the risk of occupational injuries as acute events. Results : The effects a company transfer and work load change on occupational injury was statistically significant on the risk of occupational Injuries as an acute event(RR=5.5, 95% CI=2.501-12.428; RR=3.1, 95% CI=1.963-5.017, respectively). Other stressful events were found to elevate the risk factor for the occurrence of occupational jujury, but were not significant. Conclusions : Our results suggested that transient stressful events elevated the risk factor for the occurrence of occupational injury.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.1
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• pp.15-26
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• 2021

Peptides are short chain of amino acids linked by peptide bonds. They are widely used as effective and biocompatible active ingredients in cosmetic industry. In this study, we developed novel peptide mixture and identified its anti-pigmentation effect on melanocytes and keratinocytes. Our results revealed that peptide mixture inhibited melanosome biogenesis through the regulation of microphthalmia-associated transcription factor, a key factor of melanogenesis in melanocytes. And we observed that peptide mixture inhibited melanosome uptake through the reduction of protease-activated receptor 2, a phagocytosis-related receptor in keratinocytes. Furthermore, peptide mixture activated autophagy system resulting in degradation of transferred melanosomes in keratinocytes. The anti-pigmentation effect of multi-targeting peptide mixture was assessed in a human skin equivalent model (MelanoDerm). Melanin contents in epidermal layer were significantly decreased by topical treatment of peptide mixture, suggesting that it can be applied as a novel cosmetics material having a whitening function.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.66-76
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• 2011

The heat transfer and pressure loss characteristics of a rotating two-pass channel with a guide vane in the turning region have been studied using three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis, and the shape of the guide vane has been optimized using surrogate modeling optimization technique. For the optimization, thickness, location and angle of the guide vanes have been selected as design variables. The objective function has been defined as a linear combination of the heat transfer and the friction loss related terms with a weighting factor. Latin hypercube sampling has been applied to determine the design points as design of experiments. A weighted-average surrogate model, PBA has been used as the surrogate model. The guide vane in the turning region does not influence the heat transfer in the first passage upstream of the turning region, but enhances largely the heat transfer in the turning region and the second passage. In an example of the optimization, the objective function has been increased by 13.6%.

• Journal of Family Resource Management and Policy Review
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• v.17 no.1
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• pp.199-219
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• 2013

The purpose of the study was to investigate the effects of money transfer between generations on preparation behaviors for retirement, separated into assets and saving for retirement. The survey was conducted by targeting 422 married people across the nation. The factor of money transfer between generations was defined as the inheritance and gift variable. The data were analyzed using SPSS 20. Correlation, analysis of variance (ANOVA), and multiple regressions were utilized. The results indicated that preparation behaviors for retirement are affected by the economic independence of parents, inheritance, expenses for children's education, and marriage. Retirement assets were significantly affected by inheritance, the economic independence of parents, educational expenses for children, financial assets, and amount of debt, while the significant factors related to retirement savings were interests on retirement, income, wedding expenses for children, economic independence of parents, and educational expenses for children. It was concluded that the financial preparation for retirement ought to be expanded from one household's finances to finances between generations.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.381-388
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• 2018

Microbubbles oxygen transfer to water was simulated based on experimental results obtained from the bubbles generation operated under varying liquid supply velocity to the multi-step orifices of the generator. It had been known that liquid supply velocity and bubble size are inversely related. In the oxygen transfer, a non-steady state was assumed and the pseudo stagnation caused the slow movement of bubbles from the bottom to the water surface. Two parameters were considered for the simulation: They represent a factor to correct the pseudo stagnation state and a scale which represented the amount of bubbles in supply versus time. The sum of absolute error determined by fitting regression to the experimental results was comparable to that of the American Society of Civil Engineers (ASCE) model, which is based on concentration differential as the driving force. Hence, considering the bubbles formation factors, the simulation process has the potential to be easily used for applications by introducing two parameters in the assumptions. Compared with the ASCE model, the simulation method reproduced the experimental results well by detailed conditions.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.42-50
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• 2010

The present analysis deals with a numerical procedure for optimizing the shape of elliptical dimples in a cooling channel. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis is employed in conjunction with the SST model for predictions of the turbulent flow and the heat transfer. Three non-dimensional geometric design variables, such as the ellipse dimple diameter ratio, ratio of the dimple depth to the average diameter, and ratio of the distance between dimples to the pitch are considered in the optimization. Twenty-one experimental points within design space are selected by Latin Hypercube Sampling. Each objective function values at these points are evaluated by RANS analysis and producing optimal point using surrogate model. The linear combination of heat transfer coefficient and friction loss related terms with a weighting factor is defined as the objective function. The results show that the optimized elliptical dimple shape improves considerably the heat transfer performance than the circular dimple shape.