• Membrane Journal
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• v.29 no.6
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• pp.339-347
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• 2019

Forward osmosis (FO) is operated at a lower pressure than reverse osmosis (RO), which has great advantages in terms of fouling control, maintenance, membrane cleaning, and potential energy reduction. In particular, since the membrane fouling layer of the forward osmosis process has a relatively loose and dispersed property, it is possible to control the membrane fouling by physical cleaning, unlike the reverse osmosis process. However, existing studies do not apply the proper cleaning flow rate for forward osmosis physical cleaning, and thus there is a limit that the optimal operation can not be performed. Therefore, this study aims to evaluate the justification of proper flow rate that can show high efficiency cleaning with economical energy amount. The membrane fouling experiments of the forward osmosis process were maintained at a circulating flow rate of 8.54 cm/s and the recovery rates were compared with the three cleaning flow rates. As a result of this experiment, it was confirmed that the 2 × speed cleaning showed the same efficiency as the water permeability recovery rate of the 3 × speed cleaning, and it was confirmed that the 2 × speed cleaning was an appropriate flow rate with high cleaning efficiency and economical SEC.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.675-682
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• 2017

New government, the market for stationary fuel cell systems in domestic is expected to expand in line with the policy for expanding new and renewable energy. In order to promote and expand the domestic market for stationary fuel cell systems, it is required to do research and develop for cost reduction and efficiency improvement technologies through the localization of BOP. In this study, the safety performance including the power consumption, flow rate, noise and air-tightness of the domestic fuel booster blower and the foreign fuel booster blower was evaluated and the performance improvement of the domestic blower was confirmed. As a result of the power consumption measurement and the flow rate according to the back pressure of the A company 2nd prototype and B company, the values were 73 W, 27 LPM, and 55 W, 25 LPM. These results are attributed to the improvement of performance through design changes such as CAM angle and diaphragm material.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.34-39
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• 2002

Most X-ray generator had been used do rectifier type transformer high tension generator which is supplied in a clinical diagnosis. But it is difficult to miniaturize and become light weight. Also, because the ripple rate of tube voltage is high, X-ray generating efficiency is very low. Therefore, it is supplied gradually from abroad being developed high tension generator for inverter type X-ray generator which use semi-conductor switching element for electric power that have high speed switching ability to solved these problem. But, semi-conductor element of big capacity are used by X-ray tube's big consumption power and diffusion is difficult in the small size hospital because production cost is ascending by doing digital control through DSP and product price becomes expensive. Therefore, in this paper, design and manufactured CR type voltage divider for feedback control of tube voltage of high frequency resonance type inverter and high tension transformer for high frequency to apply economical diffusion type X-ray generator which have wide output voltage and load extent. It is Proved do X-ray generator and stability of X-ray tube's output characteristics through an experiment.

• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.111-117
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• 2014

This study investigated the perception of upcycling for sensitive university students in regards to fashion trends. It was conducted through questionnaires delivered to male and female college students who majored in clothing related subjects from June 2012 to June 2013 in Gwangju. The contents for this research are general details, seriousness of environmental resources, awareness of upcycle, and purchasing intention for upcycling products. Most of the respondents said that recycling of resources is absolutely necessary due to the impact of environmental pollution and the consumption of resources. On the contrary, the experience of the respondents which purchased recycling products was low. The awareness of also was low, upcycling, internal upcycling brands and internal consumption groups, however, the decisions for subsequent purchases were positive. The reasons for the unsatisfactory of upcycling of products were due to quality and price. The reaction for many upcycle goods had the best question response rate in daily supplies part; subsequently, this study suggested 3 items, apparel products, fashion accessories, and daily supplies. In addition, a group which contains people who expend more for clothing had a lower awareness of upcycle and purchasing intention than other groups that contained some people who expend less. The results of the study can be used in data that recognize the necessary of upcycle education for university students, and develop educational programs. It can also encourage the purchase of upcycle products that reduce the consumption of resources.

• Journal of the Korean Society of Costume
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• v.51 no.1
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• pp.119-128
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• 2001

This study gives information for the enterprise to map out a positive marketing strategy and facilitate a new product development by researching and analyzing the specific character of the high income woman-brackets. In order to do that, based upon the materials of the National Statistical office, I made a selection of the high income brackets, subdividing their scholastic ability into four serfs. The subject of the study was the women from twenties to sixties among customers of a high class dress shop in Taejeon. I made up 600 questionnaires for them. using 441 of these for the statistical analysis and making available the correlation analysis, the primary factor analysis, and $X^2$-test. This study is classified into the type of women customers purchasing clothes who are the high-income brackets. Intended to study a special quality of purchasing according to income. 1. The purchasing manner of the high-income brackets customers is exposed the luxurious vain purchasing manner, the rational reasonable manner, and idiosyncrasy individual manner in order 1) The consumer of the high-income brackets in general prefer to a high class clothes. In the contrast, low-income brackets prefer to rational reasonable consumption in spending money on clothes. 2) The favorite consumption manner of the high income brackets is the luxurious vain purchasing manner. This consumption values the more symbolic means the things show than owing the goods. 2. The higher standard of education and younger tends to be high in the luxurious, vain purchasing. 3. The unreasonable purchasing show an high irrelation at the impulse buying arid self-satisfaction. 4. Self-satisfaction shows the highest interrelation than any other variations in the concern of clothes. 5. The symbolic images which exerts an influence upon purchasing manner are the notable elements of constituting as growing older. 6. The high standard of education prefers to the rational resonable purchasing, but on the other hand shows a high rate at the unreasonable individual purchasing manner.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.523-529
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• 2009

Smart sensor is known as intelligent sensor, it is different with other conventional sensors in the case of intelligent system embedded on it. Smart sensor has many benefits e.g. low-cost in usage, self-decision and self-diagnosis abilities. This sensor consists of perception element(sensing element), signal processing and technology of communication. In this work, a bridge and structure of smart sensor has been investigated to be capable to condition monitoring routine. This investigation involves low power consumption, software programming, fast data acquisition ability, and authoritativeness warranty. Moreover, this work also develops smart sensor to be capable to perform high sampling rate, high resolution of ADC, high memory capacity, and good communication for data transfer. The result shows that the developed smart sensor is promising to be applied to various industrial fields.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1335-1336
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• 2008

A compact diode-pumped microchip(DPM) green light source which consist of pump LD, $Nd:YVO_4$, KTP and a built-in thermoelectric element has been fabricated for laser projection display. The volume of the source is as small as $0.7\;cm^3$ and we obtained the output power of 25mW with the average electric power consumption in pump LD of 304mW which correspond to the electrical-to-optical efficiency of 7.8%. Another approach using quasi phase matching(QPM) technique has been attempted. We obtained the output power of 90mW of green beam with 350mW pumping of a $Nd:YVO_4$ laser with 20-kHz rep. rate and 10-ns pulse duration. Detailed characteristics and issues of the DPM and QPM green light sources will be addressed.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.6
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• pp.381-390
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• 2015

The efficient design of a transport protocol contributes to energy conservation as well as performance improvement in wireless sensor networks (WSNs). In this paper, a node-density-aware transport protocol (NDTP) for intra-cluster transmissions in WSNs for monitoring physical attributes is proposed, which takes node density into account to mitigate congestion in intra-cluster transmissions. In the proposed NDTP, the maximum active time and queue length of cluster heads are restricted to reduce energy consumption. This is mainly because cluster heads do more works and consume more energy than normal sensor nodes. According to the performance evaluation results, the proposed NDTP outperforms the conventional protocol remarkably in terms of network lifetime, congestion frequency, and packet error rate.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.96-99
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• 1990

Recently, electric energy consumption pattern shows very high peak load with low load factor. This Load pattern have made electric utilities be interested in Load Management, many studies are reported. But most of these studies are concerned with Rate - Load shape relation, a few of these are concerned with generating cost reduction. In this study, the effect of Load Management is incorporated to establish optimal Generation Expansion Planning. Using avoided cost, optimal generation expansion planning is achieved to make maximum avoided cost of Electric utility. Dynamic programming technique is used to solve this algorithm.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.156-162
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• 2020

Wireless Sensor Network (WSN) field is mainly studied to monitor and characterize large-scale physical environments to track various environmental or physical conditions, such as temperature, pressure, wind speed and humidity. WSN can be used in various applications such as wild surveillance, military target tracking and monitoring, dangerous environmental exploration and natural disaster relief. We design probabilistic mobile models that apply to mobile ad hoc network mobile environments. A probabilistic shift model proposed by dividing the number of moving nodes and the distance of travel into two categories to express node movement characteristics. The proposed model of movement through simulation was compared with the existing random movement model, ensuring that the width and variation rate of the first node node node node (FND) was stable regardless of the node movement rate. In addition, when the proposed mobile model is applied to the routing protocol, the superiority of network life can be verified from measured FND values. We overcame the limitations of the existing random movement model, showing excellent characteristics in terms of energy efficiency and stable in terms of changes in node movement.