• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.193-201
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• 2015

This paper deals with the influence of leakage flow existing in SHF pump model on the analysis of internal flow behaviour inside the vane diffuser of the pump model performance using both experiments and calculations. PIV measurements have been performed at different hub to shroud planes inside one diffuser channel passage for a given speed of rotation and various flow rates. For each operating condition, the PIV measurements have been trigged with different angular impeller positions. The performances and the static pressure rise of the diffuser were also measured using a three-hole probe. The numerical simulations were carried out with Star CCM+ 9.06 code (RANS frozen and unsteady calculations). Some results were already presented at the XXth IAHR Symposium for three flowrates for RANS frozen and URANS calculations. In the present paper, comparisons between URANS calculations with and without leakages and experimental results are presented and discussed for these flow rates. The performances of the diffuser obtained by numerical calculations are compared to those obtained by the three-holes probe measurements. The comparisons show the influence of fluid leakages on global performances and a real improvement concerning the efficiency of the diffuser, the pump and the velocity distributions. These results show that leakage is an important parameter that has to be taken into account in order to make improved comparisons between numerical approaches and experiments in such a specific model set up.

• 한국운동역학회지
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• 제26권3호
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• pp.323-331
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• 2016

Objective: The aims of this study were 1) to develop easy-to-use rhythmic balance training equipment for the elderly and 2) to investigate the effect of training with the equipment on balance and physical function. Method: Twenty-one elderly individuals (age: $75.4{\pm}3.34yrs$, height: $152.07{\pm}4.81cm$, weight: $58.35{\pm}8.34kg$) participated in this study. Each participant underwent balance and physical function testing before and after 12 weeks of training with the equipment. Y-balance (i.e. dynamic balance) and one leg static balance tests were used for balance testing, and timed up- and-down-stairs and five times sit-to-stand tests were used for physical function testing. A paired t test was used to determine whether there was a significant pre- and post-training difference. Results: The rhythmic balance training equipment provided a fun and motivating training program with age-friendly music, dance movements for lower extremity strength training, and touch screen controls with simple features. Post-training left foot dynamic balance was significantly greater (p<.05), and static balance with eyes open was significantly improved (p<.05) compared to pre-training. Completion of the timed up-and-down-stairs and the five times sit-to-stand tests was significantly shorter (p<.05) compared to pre-training. Conclusion: Training using the equipment developed in this study improved balance and physical function in elderly participants.

• 한국인쇄학회지
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• 제16권2호
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• pp.75-89
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• 1998

FM screening has been praised for its apparent resolution advantage over conventional AM screening. FM screening is also known for its criticalness of film output and difficulties in the proofing stage because of the microdot formation. However, FM screening is not a well understood process from press performance point of view. This study was carried out for the purposes of introducing the availability of hifi-offset printing to domestic printing industries and evaluating the print qualities between 300lpi AM screen and FM screen with the equivalent sized microdots to 4-5% dot area of the 300lpi AM screen, together with comparing with 175lpi AM screen representing a conventional printing. Solid density, dot gain, color gamut and some other quality properties were measured and discussed.

• 공학교육연구
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• 제16권3호
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• pp.79-86
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• 2013

The purpose of this study was to analyze the factors related to the satisfaction of the introductory engineering education program for the employees, who majored liberal arts or commerce, among the educational programs for industrial workers which are performed as an effort to spread the performance of the Innovation Center for Engineering Education, and reinforce the competitiveness through effective program operation. This study was performed on the basis of CIPP evaluation model (context, input, process, product). A factorial analysis and a regression analysis were conducted based on a survey made on 87 persons who completed the introductory engineering education program among the employees of D group who majored liberal arts or commerce. It is expected that this study will contribute toward suggesting the implications for designing and operating the educational programs for industrial workers in order to find out the important factors of satisfaction and to conduct the education operation with professionalism.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.180-184
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• 2017

In this study, we examine the electrical properties of diketopyrrolopyrrole (DPP) containing polymer semiconductors that have been reported to show high performance with ambipolar characteristics. We prepared three different DPP based polymer semiconductors (PDPPTPT, PDPP3T, and PDPP2T-TT) and fabricated organic thin film transistors (OTFTs) with ambipolar polymer semiconductors as an active layer. All three DPP polymers showed only p-type properties at initial measurements. However, after annealing in vacuum oven for 24 hours, it was found that the DPP based polymers have both p-type and n-type properties. It is speculated that the residual impurities supposedly regarded as a strong electron trap source were eliminated during the vacuum process.

• 한국인쇄학회지
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• 제16권3호
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• pp.109-120
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• 1998

FM screening has been praised for its apparent resolution advantage over conventional AM screening. FM screening is also known for its criticalness of film output and difficulties in the proofing stage because of the microdot formation. However, FM screening is not a well understood process from press performance point of view. This study was carried out for the purposed of introduction the availability of hifi-offset printing to domestic printing industries and evaluating the print qualities between 300pli AM screen and FM screen with the equivalent sized microdots to 4-5% dot area of the 300lpi AM screen, together with comparing with the 175lpi AM screen representing a conventional printing. Solid density, dot gain, color gamut and some other quality properties were measured and discussed.

• 한국인쇄학회지
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• 제14권1호
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• pp.89-114
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• 1996

Liquid crystal-polymer composite(LCPC) films consisting of a continuous LC phase embedded in a three-dimensional network of polymer matrix are formed by photopolymerization-induced phase separ on. The LCPC films are switched from a light-scattering stats to a highly transparent stats on the application of electric fields. Since the alignment of LC molecular determines the electro-optical properties of films, the requirement for good contrast is to generate the nematic phase at high concentration. On the other hand, the concentration of UV-curable monomer must be increased above some critical value to from the flexible matrix of unbounded polymer. The mixing ratio of LC and UV-curable monomer affects the electro-optical and viscoelastic properties of LCPD films in two opposing ways. By controlling the phase separation process, at an LC fraction of 0.7, the maximum performance of LCPC films has been achieved, the response time of which is 2ms on the application of electric fields.

• International Journal of Advanced Culture Technology
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• 제5권2호
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• pp.98-105
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• 2017

Smartphones are fast growing in the IT market and are the most influential devices in our daily life. Smartphones are being studied for their use in body sensor networks with excellent processing power and wireless communication technology. In this paper, we propose a coordinator design that provides data collection, classification, and display using based on Android-smartphone in multiple sensor nodes. The coordinator collects data of sensor nodes that measure biological patterns using wireless communication technologies such as Bluetooth and NFC. The coordinator constructs a network using a multiple-level scheduling algorithm for efficient data collection at multiple sensor nodes. Also, to support different protocols between heterogeneous sensors, a data sheet recording wireless communication protocol information is used. The designed coordinator used Arduino to test the performance of multiple sensor node environments.

• International Journal of Contents
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• 제10권2호
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• pp.1-8
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• 2014

This paper discusses designing an interdisciplinary learning environment to promote learning of the liberal arts for advanced music students in order to expand the boundaries of their education experience beyond the technical mastery of their musical instruments. The paper discusses the utilization of salient features of information, communications, and technology and the use of instructional theory to promote the understanding of how individual pieces of music can be connected to knowledge of the context in which they were created to support the understanding of the relationship between experience in the world and musical composition.

• 한국인쇄학회지
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• 제29권3호
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• pp.143-153
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• 2011

Digital leader caught seat by modern's everyday life tool now by popularization of smart device such as Smart phone and Tablet PC. Therefore, desire of readers about electronic book practical use is increasing based on convenience and economic performance of electronic book. 1971, Michael S. Hart established Project Gutenberg to produced first electronic book because inputs American Independence Declaration Statement by computer and produce more electronic books. After that, an electronic book technology repeats several times development and American electronic book take is increasing rapidly. Sales volume of electronic books is dramatically increasing in Korea since digital device such as Smart phone and Tablet PC became popular. This research attempts to analyze factors influencing on shifting from paper book to electronic book. Results of this research proposed grounds for building business strategy. Finding is the factor of social influence is only significant to acceptability intention. It means user of e-Book enhance their acceptability intention along social phenomena.