• Korean Journal of Materials Research
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• v.19 no.4
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• pp.179-185
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• 2009

We fabricated thermally evaporated 30 nm-Ni/(20 nm or 60 nm)a-Si:H/Si films to investigate the energy-saving property of silicides formed by rapid thermal annealing (RTA) at temperatures of $350^{\circ}C$, $450^{\circ}C$, $550^{\circ}C$, and $600^{\circ}C$ for 40 seconds. A transmission electron microscope (TEM) and a high resolution X-ray diffractometer (HRXRD) were used to determine the cross-sectional microstructure and phase changes. A UVVIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were employed for near-IR and middle-IR absorbance. Through TEM and HRXRD analysis, for the nickel silicide formed at low temperatures below $450^{\circ}C$, we confirmed columnar-shaped structures with thicknesses of $20{\sim}30\;nm$ that had ${\delta}-Ni^2Si$ phases. Regarding the nickel silicide formed at high temperatures above $550^{\circ}C$, we confirmed that the nickel silicide had more than 50 nm-thick columnar-shaped structures with a $Ni_{31}Si_{12}$ phase. Through UV-VIS-NIR analysis, nickel silicide showed almost the same absorbance in the near IR region as well as ITO. However, in the middle IR region, the nickel silicides with low temperature showed similar absorbance to those from high temperature silicidation.

• Hwankyungkyoyuk
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• v.24 no.1
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• pp.88-101
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• 2011

This study aims to address the current status of ESD(Education for Sustainable Development) in Korean universities since UN DESD was launched in 2005, and to explore the possibilities and challenges in them. For this purpose we conducted questionnaire surveys and case studies on members of university communities which were engaged in green campus activities or interested in SD and ESD. Results of questionnaire surveys showed that most of those who answered the questionnaire were well aware of SD, but had comparatively low understanding of ESD. The highest number of respondents answered that since 2005 they had newly opened courses on SD or ESD, or added contents on SD or ESD to existing ones. Ratio of network participation among ESD-related universities was over 30%, and they appeared to have the highest partnership ratio with NGOs. Not many universities had policies for sustainable school management, and 'green space conservation and ecosystem protection' and 'energy and resource saving campaign and monitoring' were most common sustainable environment protection activities. Through case studies on eight universities, it was discovered that ESD programs in universities took various forms such as whole-university approaches, participatory courses and club activities. We suggest that it is needed to make efforts to find out good examples of ESD in Korean universities and share the results with university leaders, professors and staffs for further development of ESD.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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• pp.544-551
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• 2015

This study was conducted to determine the LCC of apartment complexes with district heating and a cogeneration system. For the purpose of analyzing LCC according to the size of the apartment complex, 500, 1,500, and 4,000-unit model apartments were selected. Analysis was performed on the design of the heating system and the life cycle cost including total construction cost, maintenance and operation cost for the duration of the project period (15 years). According to the calculated results, 1) The initial cost of the cogeneration system for 500, 1,500, and 4,000-unit apartments is higher than that of the district heating system by 20%, 13%, and 12%, respectively. 2) In the case of the cogeneration system, the payback period by electric generation was found to be 5.21, 4.92 and 4.47 years, and saving cost was calculated to be 29 billion won, 94 billion won and 262 billion won after the payback period for 500, 1,500, and 4,000-unit apartments, respectively. 3) The LCC values of the cogeneration system were 1.12, 1.07 and 1.06 times larger than those of the district system according to the size of the apartment complex. In this study, the district heating system was found to be more efficient than the cogeneration system in terms of LCC reduction. 4) District heating is affected by fuel bills, so energy efficiency should be improved through recovering waste heat (incineration heat, etc.). Also, district cooling should be provided according to heat use to keep the temperature high in winter and low in summer.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.4
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• pp.540-545
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• 2007

In this thesis, we introduce and investigate new architectures and comprehensive design methodologies of intelligent dimming converter and evaluate the proposed model and the system through a series of numeric experiments. Electronic ballast enable prolongation of life foy Fluorescent-Lamp and ballast. However, There are no merit in case that user impossible manual control. Therefore in this paper, we put emphasis on the design of electronic ballast based on intelligent dimming converter and the energy saving according to the day-light and the user settings by applying the intelligent model to a fluorescent lamp. Also, we show the superiority of the proposed Intelligent dimming converter through the evaluation of performance with conventional electronic ballast by applying the intelligent model to hardware of systems.

• KIEAE Journal
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• v.16 no.4
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• pp.63-69
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• 2016

Purpose: This preliminary study investigated a potential of the water wall systems that provide heat storage and natural lighting control simultaneously. Method: In order for transparency of the water wall to be controlled, the study first proposed two measures: to adjust transparency of the water wall; to control transparency of water wall surface. The performance of two measures then was verified and compared by experiments. In addition, a trade-off between heat collect and heat storage resulting from using additive for adjusting transparency was investigated. Result: The experiment showed that the two measures are similar in performance. The investigation of trade-off relation showed the additive should have the same heat storage as the water to prevent decrease in thermal performance of the water wall. As an economical measure to control transparency of the water wall, this study suggested a measure of secondary heat transfer systems using shading device that first absorbs solar radiation and then transfers heat to the water wall. The experiment show that performance of the proposed measure is similar to controlling transparency of water wall surface. In conclusion, it is expected that the performance of the water wall can be economically maximized by using the proposed mean in terms of heating, cooling and lighting energy saving.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.78-84
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• 1998

The fluid system such as, the quantity control of raw water, chemicals control in the purification, the waste water system as well as in the feed water or circulation system of the power plant and the ventilation system is controlled with the valve and moter pump. The system's performance and the energy saving of the fluid systems depend on control of method and delicacy. Until, PI controller use in these system but it cannot control delicately because of the coupling in the system loop. In this paper we configure a single flow system to the multi variable system and suggest the application of 2-DOF PID controller and the tuning methods by the neural network to the electrical power of the flow control system. the 2-DOF controller follows to a setpoint has a robustness against the disturbance in the results of simulation. Keywords Title, Intelligent control, Neuro control, Flow control, 2 - DOF control., 2 - DOF control.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.45-48
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• 2011

The electrodeless fluorescent lamp is relatively new luminaire and has been known as the high energy saving lamp which has long life and environment-friendly. But these kind of lamps have some risks to cause harmful radio interference unavoidably due to its own inductive characteristics. In this paper we measured the radio disturbance characteristics of the induction lamp with the operating frequency at 250 kHz, and compared the values with the limits of relevant standards. Finally we have estimated the interference protection distance between the induction lamps and some services around their operating frequencies, and considered the desirable future scopes and limits of the applications for these kind of lamps.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.29-31
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• 2009

Optimal efficiency control of synchronous reluctance motor(SynRM) is very important in the sense of energy saving and conservation of natural environment because the efficiency of the SynRM is generally lower than that of other types of AC motors. This paper is proposed an efficiency optimization control for the SynRM which minimizes the copper and iron losses. The design of the speed controller based on fuzzy-neural networks (FN)-PI controller that is implemented using fuzzy control and neural networks. There exists a variety of combinations of d and q-axis current which provide a specific motor torque. The objective of the efficiency optimization control is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency optimization control scheme. The proposed algorithm allows the electromagnetic losses In variable speed and torque drives to be reduced while keeping good torque control dynamics. The control performance of the proposed controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.

• Textile Coloration and Finishing
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• v.8 no.5
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• pp.7-16
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• 1996

The air-flow dyeing machine is a new type of dyeing machine. Which is an energy saving type to be able to dye the fabrics with the lowest liquor ratio and in shorter time. This machine is operated with an aerodynamic system rather than a hyd raulic system for traditional jet or overflow dyeing. An air-flow dyeing machine(Green-flow) by the use of aerodynamic technology was developed and compared with the Luft-roto machine made by Thies Company, Germany, in this study. Three samples were dyed with both machines under the same dyeing conditions and color fastness, dyeing levelness, drapability, and mechanical properties of these samples were compared. The results were as follows; Both machines have almost the same dyeability. The dyeability was good at liquor ratio of 1: 3.5 and the speed of 450yds/min. The order for drapability was Crepe de Chine > Cool Peach > Charmeuse. Except for the color fastness of sublimation being below class 4, most color fastness of samples dyed with Green-flow m/c were above class 4. The maximum speed was 510yds/min. for Crepe de Chine and the standard deviation of K/S value was lower for Charmeuse and Cool Peach when employed on the "Green-flow" machine and lower for Crepe de Chine when employed on the Luft-roto machine. Comparing with dyeing of the Green-flow machine and that of the Luft-roto machine, the RT of the Charmeuse was found to be higher with the Green-flow machine and thus the sample had an improved wrinkle recovery. LT and WT of Cool Peach were higher, and shear properties(G, 2HG, 2HGS) of Crepe de Chine were higher, both turning out as suitable for clothing. clothing.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.5
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• pp.520-529
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• 2002

Though BIFS is a complex description language that represents MPEG-4 content as text or bit streams, most traditional MPEG-4 content authoring tools are developed for a BIFS expert. Before using these tools, many authors must invest much time and energy in acquiring knowledge of BIFS. In this paper, we suggest a new manner for saving these efforts. Our proposal supplies the convenient user interface of traditional multimedia authoring tools for MPEG-4 authors and interprets the authored information and transforms it into BIFS. In our user interface, the author generates the minimal authoring information requested for generating BIFS; the BIFS generation module then transforms the information into BIFS format using predefined BIFS construction rules. The resulting BIFS consists of the Scene Tree and the Object Descriptor and Route; they are used for constructing MP4 standard files by mixing with the Elementary Stream.