• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.541-544
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• 2005

This study presents the integrated modeling approach to simulate the proton exchange membrane (PEM) fuel cell system for vehicle application. The fuel cell system consisting of stack and balance of plant (BOP) was simulated with MATLAB/Simulink environment to estimate the maximum system power and investigate the effect of BOP component sizing on system performance and efficiency. The PEM fuel cell stack model was established by using a semi-empirical modeling. To maximize the net efficiency of fuel cel1 system, multi-variable optimization code was adopted. Using this method the optimized operating values were obtained according to various system net power levels. The fuel cell model established was co-linked to AVL CRUISE, a vehicle simulation package. Through the vehicle simulation software, the fuel economy of fuel cell powered electric vehicle for two types of driving cycles was presented and compared. It is expected that this study tan be effectively employed in the basic BOP component sizing and in establishing system operation map with respect to net power level of fuel cell system.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.63-63
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• 2011

The donor-${\pi}$-acceptor (D-${\pi}$-A) chromophoric dye system has received great attention in variety fields such as electroluminescent materials, sensors and optoelectronic devices. There are many research activities focused on the development for abovementioned application materials with the high-performance properties. In the previous work, we are reported that novel D-${\pi}$-A dye, 2-[4-(9H-carbazol-9-yl)benzylidene]-2,3-dihydroinden-1-one, is successfully attained and exhibited a positive fluorescence solvatochromism. In this work, the molecular structure and packing geometry of 2-[4-(9H-carbazol-9-yl)benzylidene]-2,3-dihydroinden-1-one was discussed by their conformational structure. Their single yellow prism crystal having approximate dimensions of $0.30{\times}0.10{\times}0.10$ mm was carried out with a Rigaku RAXIS RAPID imaging plate area detector with graphite monochromated $CuK_{\alpha}$ radiation. Their crystal structure were solved by using the CrystalStructure crystallographic software package.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.506-516
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• 2005

This paper deals with an investment scheduling problem of maximizing net present value of dividend with reinvestment allowed, where each investment has certain capital requirement and generates deterministic profit. Such deterministic profit is calculated at completion of each investment and then allocated into two parts, including dividend and reinvestment, at each predetermined reinvestment time point. The objective is to make optimal scheduling of investments over a fixed planning horizon which maximizes total sum of the net present values of dividends subject to investment precedence relations and capital limit but with reinvestment allowed. In the analysis, the scheduling problem is transformed to a kind of parallel machine scheduling problem and formulated as an integer programming which is proven to be NP-complete. Thereupon, a depth-first branch-and-bound algorithm is derived. To test the effectiveness and efficiency of the derived algorithm, computational experiments are performed with some numerical instances. The experimental results show that the algorithm solves the problem relatively faster than the commercial software package (CPLEX 8.1), and optimally solves the instances with up to 30 investments within a reasonable time limit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.92-99
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• 2002

Transient in an electric distribution system are mainly generated by switching. This paper presents analysis of switching surge and means of limiting the voltage magnification transient for high voltage power systems by using the EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor contraction capacitor banks to harmonics filters. An inductance in series with the capacitor bank was used to decrease the transient voltage at the customer bus to acceptable levels. And also simulation results used the EDSA harmonics analysis program show the effect of harmonics reduction.

• The Korean Journal of Emergency Medical Services
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• v.24 no.1
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• pp.85-92
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• 2020

Purpose: The purpose of this study was to analyze the English abstract key words found within the Korea Society of Emergency Medical Services journal using text mining techniques to determine the adherence of these terms with Medical Subject Headings (MeSH) and identify key word trends. Methods: We analyzed 212 papers that were published from 2012 to 2019. R software, web scraping, and frequency analysis of key words were conducted using R's basic and text mining packages. Additionally, the Word Clouds package was used for visualization. Results: The average number of key words used per study was 3.9. Word cloud visualization revealed that CPR was most prominent in the first half and emergency medical technician was most frequently used during the second half. There were a total of 542 (64.9%) words that exactly matched the MeSH listed words. A total of 293 (35%) key words did not match MeSH listed words. Conclusion: Researchers should obey submission rules. Further, journals should update their respective submission rules. MeSH key words that are frequently cited should be suggested for use.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.81-87
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• 2010

This paper proposes a G-BLAST(BLAST using Grid Computing) system, an integrated software package for BLAST searches operated in heterogeneous distributed environment. G-BLAST employed 'database splicing' method to improve the performance of BLAST searches using exists computing resources. G-BLAST is a basic local alignment search tool of DNA Sequence using grid computing in heterogeneous distributed environment. The G-BLAST improved the existing BLAST search performance in gene sequence analysis. Also G-BLAST implemented the pipeline and data management method for users to easily manage and analyze the BLAST search results. The proposed G-BLAST system has been confirmed the speed and efficiency of BLAST search performance in heterogeneous distributed computing.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.35-39
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• 2013

This paper reports numerical study results with respect to the thermal behavior of a natural convection cooled hybrid fin heat sink (HFH). The HFH consists of hybrid fins, hollow pin fins integrated with plate fins. The thermal performance of the HFH was numerically investigated by employing a commercial CFD software package and compared with that of the pin fin heat sink (PFH). Numerical study has found that array-based and mass-based heat transfer coefficients of the HFH are 12% and 37% greater than those of the PFH, respectively. Extended surface area and lighter weight may explain the better thermal performance of the HFH than the PFH.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.89-99
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• 1999

The automatic design of shell & tube type oil cooler can be used in real industrial environments. Since the automatic design system is intended to be used in small companies, it is designed to be operated well under environments of CAD package in the personal computer. It has adopted GUI in design system, and has employed DCl language. Design parameters to be considered in the design stage of shell and tube type oil cooler are type of oil cooler, outer diameter, thickness, length of tube, tube arrangement, tube pitch, flow rate, inlet and outlet temperature, physical properties, premissive pressure loss on both sides, type of baffle plate, baffle plate cutting ratio, clearance between baffle plate outer diameter and shell inner diameter and clearance between baffle plate holes. As a result, the automatic design system of shell & tube type oil cooler is constructed by the environment of CAD software using LISP. We have built database of design data for various kinds of shell & tube type oil coolers. The automatic design system have been assessed and compared with existing specification of design. Good agreement with Handbook of heat exchanger and design dta of real industrial environments has been found.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.133-145
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• 2000

Plastic molding designers are frequently faced with optimizing multiple defects in injection molded parts. these defects are usually in conflict with each other, and thus a tradeoff needs to be made reach a final compromised solution. In this study, an automated injection molding design methodology has been developed to optimize multiple defects of injection molded parts. Two features of the proposed methodology are as follows: one is to apply the utility theory to transform the original multiple objective optimization problem into single objective optimization problem with utility as objective function, the other is an implementation of a direct search-based injection molding optimization procedure with automated consideration of process variation. The modified complex method is used as a general optimization tool in this research. The developed methodology was applied to an actual molding design and the results showed that the methodology was useful through the CAE simulation using a commercial injection molding software package. Applied to production, this study will be of immense value to industry in reducing the product development time and enhancing the product quality.

• The Korean Journal of Health Service Management
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• v.9 no.2
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• pp.13-22
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• 2015

This study confirmed that the organizational health of nurses have an effect on customer orientation. This survey was conducted March 1 to 31, 2014 and a total of 210 questionnaires were used in the analysis. Descriptive statistics, t-test, ANOVA, factor analysis, and regression analysis were used to analyze the collected data in the SPSS software package. The findings are summarized as follows: First, the business environment and community-oriented organizations on health factors had an influence on customer orientation(p<.05, p<.001). Among the demographic factors, graduating from college as relevant to customer orientation. Seniority and rank in the lower tier showed that customer orientation is vulnerable. Second, when leadership was added to a conventional model, it had no significant effect on the dependent variables. The influence of community-oriented business environment factors on customer orientation was statistically significant(p<.01). In the result, we should apply proper organizational health factors to hospitals by investigating leadership, because there was difference in customer orientation according to type of leadership.