• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.65-72
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• 2000

This paper proposes a Push type High Frequency DC-DC Converter using Zero Voltage Switching to reduce turn on and off loss at the switching instants. This paper has a advantage which is able to operating safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC power supply. The capacitor $(C_1, C_2)$ connected in switch are a common using as resonance capacitor and ZVS capacitor. The analysis of the proposed high frequency resonance DC-DC converter is generally described by using normallized parameter, and we has evaluated characteristic values which is needed to design a circuit. We conform a rightfulness of theoritical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.330-332
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• 2009

Highly stable bottom gate thin film transistors(TFTs) with a zinc indium tin oxide(Zn-In-Sn-O:ZITO) channel layer have been fabricated by rf-magnetron co-sputtering using a indium tin oxide(ITO:90/10), a tin oxide and a zinc oxide targets. The ZITO TFT (W/L=$40{\mu}m/20{\mu}m$) has a mobility of 24.6 $cm^2$/V.s, a subthreshold swing of 0.12V/dec., a turn-on voltage of -0.4V and an on/off ratio of >$10^9$. When gate field of $1.8{\times}10^5$ V/cm was applied with source-drain current of $3{\mu}A$ at $60^{\circ}C$, the threshold voltage shift was ~0.18 V after 135 hours. We fabricated AM-OLED driven by highly stable bottom gate Zn-In-Sn-O TFT array.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.147-161
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• 2001

Efficiency and competitive power in agribusiness management has became important issue due to the rapid changes in farming environment under new WTO agreement. To increase competitive power, small-sized petty farm should be restructured to be specialized large-scaled farming system. Trust farming corporation(TFC) has been introduced to increase farm productivity and competitive power through large scale farming system and refined management skills. Eventually, TFCs are expected to revitalize rural economy. TFCs are increasing in numbers, but they are unsatisfactory in quality often with insolvent operations. The typical problems with TFCs are internal conflicts among members, lack of management abilities and incentives, inefficiency in machinery use, and insolvent operations. The self effort by members and legal-institutional assistance can alleviate the negative factors against the rational for cooperative management and sustain TFCs. This study identifies the management problems of TFCs. To provide the methods for increasing management efficiency, improving rational management skills, and hence to help revitalizing the rural economy with competitive power, 20 TFCs in Nonsan County is surveyed. The major findings are as follows; 1) According to the survey result of 20 trust farming corporations, investments on the accumulation of knowledges and information, accounting management, machinery management are required due to the present lack of management/accounting ability. There also exist problems associated with revenue sources, labor uses, and public recognition. To increase management efficiency under current situation, corporations should import active business plans with expanding farming execution and off-farm season business. 2) Based on the result of corporations' business analysis, more than 50% of the corporations were not able to provide profit dividends to the members. It suggests that trust farming corporations need appropriate and stable revenue sources to sustain business. It is also required that corporations should reduce their excessive expenditure on fixed assets. 3) Theoretical amounts of consignment fees for tillage operation, planting, and harvesting were found to be 338,874 won, 216,596 won, and 332,318 won, respectively. Although actual levels of fee are 110%~120% of these theoretical levels of consignment fee, corporations' expected fee levels could not be acheived because of competency of consignment market.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.133-143
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• 2017

The purpose of this study was to investigate the status of agricultural management accounting information, education status, and policy demands through a questionnaire survey of advanced agricultural managers. These people are expected to play a key role in the changing agricultural environment in Korea. Based on survey results, several policy implications were derived for the advanced agricultural managers' agricultural management accounting information record activation. Survey results of 303 respondents identified that 63.4% of them record their agricultural management accounting information. The biggest reason given for not recording this information was lack of time for record keeping. The biggest problem was a 'lack of Question and Answer system'. In addition, 37.2% of the respondents were not aware of the current agricultural accounting guidelines. In terms of education, 71.3% of the respondents have completed course work in accounting and responded that an 'On-off parallel education system', which offers both online and offline classes, was the most effective method to prevent dropout. Respondents thought that agricultural management accounting records were helpful for the management of agriculture and their participation in government policies. They also thought that customized education programs should be further implemented for enhancing the effectiveness of education programs, and 'One-stop Question and Answer system on related web sites and organizations' is required for them to keep better records. The following policy implications can be derived from the survey results. First, interoperability between agricultural management accounting information recording programs is needed. Second, accessibility should be strengthened. Third, the education system needs to be improved. Fourth, voluntary participation should be encouraged. Last, the government needs to establish a post-verification system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.597-603
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• 2014

The cargo of ships and offshore structures is the number of oil of combustibility and volatile, oil processing cargo. Furthermore heavy cargo of the vehicle or container box or bulk cargo are occupied the remainder of cargo. In addition, there is a possibility to move the location of the cargo and the vessel because it is received periodic / non-periodic a load of wave and ocean current. Therefore a shipboard hazard is much greater than onshore industry hazard. Monitoring and preparation for safety are necessary things because there is always risk of accidents arise from the impact of the freight and cargo of ships and offshore structures. In this study, we conducted a study with respect to the introduction of the wireless sensor network monitoring system to ensure the safety of the crew and workers on shipboard.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.895-904
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• 2017

In this paper, we propose an IoT based smart outlet system for one-person household with electric safety, electric energy consumption management and transmission of messages to the reserved contacts by connecting the emergency network. The proposed smart outlet system is implemented by parsing packet data and protocol between server, module, application and WiFi AP receiver. The WiFi AP built for communication can be used not only for the outlet but also for the gas barrier, the door lock and the like. In addition, the proposed method can provide the remote monitoring function by receiving the amount of power of the receptacle received through the AC current sensor (SCT-013) in real time. The smart outlet system is expected to be capable of automatically shutting off the power in case of emergency through automatic power use analysis in addition to the standby power cutoff function.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.43-49
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• 2018

Recently, with the rapid increasing demands for data services on the Internet, the need for large-scale data centers has been increased. However, these data centers consume enormous amounts of energy to run numerous servers and equipment. In this paper, we therefore propose a novel scheme to save energy in multimedia servers by concentrating the load on specific servers according to the current load level of the overall system and turning them off immediately. To this end, the number of server groups in which each video is stored is determined according to its popularity so that video playback requests can be evenly distributed to the entire system. Finally, through extensive simulations, we show that our proposed data placement and power management scheme in multimedia servers significantly reduces energy consumption by decreasing the number of servers whose powers are on when compared with the existing method, while maintaining the service quality.

• The Journal of Korean Association of Computer Education
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• v.5 no.1
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• pp.57-66
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• 2002

Real time multimedia data services have been made possible by the rapid development of the computer and internet technology. Based on the technology, Many multimedia system developer try to use VOD(Video on Demand) and GVA technologies for distance education. However the system has mainly been developed to provide the video screen of good quality in real time and to compose contents efficiently. Not many researches and developments have been made for providing the users that is taking distance education with various types of service using VOD and GVA. Therefore In this paper we have designed and implemented an active on-demand multimedia service system to improve user-side service quality in distance education using VOD and GVA service. The on-demand multimedia service system can prominently help users to save the time and effort to search and select the studying data by this paper enables off-line search functions through E-mail and periodical current awareness service supported by PUSH technology, user oriented information booking supported by SDI service and feedback service.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2207-2212
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• 2012

Dimethylaluminum isopropoxide (DMAI, $(CH_3)_2AlO^iPr$) as a single precursor, which contains one aluminum and one oxygen atom, has been adopted to deposit non-stoichiometric aluminum oxide ($AlO_x$) films by low pressure metal organic chemical vapor deposition without an additional oxygen source. The atomic concentration of Al and O in the deposited $AlO_x$ film was measured to be Al:O = ~1:1.1 and any serious interfacial oxide layer between the film and Si substrate was not observed. Gaseous by-products monitored by quadruple mass spectrometry show that ${\beta}$-hydrogen elimination mechanism is mainly contributed to the $AlO_x$ CVD process of DMAI precursor. The current-voltage characteristics of the $AlO_x$ film in Au/$AlO_x$/Ir metalinsulator-metal (MIM) capacitor structure show high ON/OFF ratio larger than ${\sim}10^6$ with SET and RESET voltages of 2.7 and 0.8 V, respectively. Impedance spectra indicate that the switching and memory phenomena are based on the bulk-based origins, presumably the formation and rupture of filaments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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• pp.527-536
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• 2015

Studies for the reduction of lighting energy have been done using technologies such as user and location awareness. However, the focus of current research on location-based lighting control has been on energy reduction, which can lead to other issues including an imbalance in indoor illumination. This study proposes a lighting control system applying general illumination and technology for user and location awareness. The proposed lighting control system reduced lighting energy by 72.1%, 66.5% and 62.3% for 1, 2 and 3 users, respectively, compared to the On/Off lighting control system. This lighting control system causes an increase in lighting energy of 35.8% and 10.9% for 1 and 2 users compared to the lighting control system with user and location awareness, while a reduction of 9.4% was seen for 3 users. This means that the proposed system provides more effective energy reduction for a room with multiple occupants as it is based on the general lighting control scheme. The lighting control system applying general illumination and technology of user and location awareness improved the uniformity factor by 32.0%, 39.4% and 33.4% for 1, 2 and 3 users, respectively.