• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.172-176
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• 2009

We developed a program, "CogenSim-$\mu$," to simulate the operation of micro-combined heat and power (${\mu}CHP$) system. The CogenSim-$\mu$ can reflect the variation of energy efficiency by handling the real-time loads (heat and power) fluctuation. The result obtained using this program was compared with the real operation of 30 kWe gas engine driven ${\mu}CHP$. It was found that the CogenSim-$\mu$ could predict the amount of generated-power, recovered-heat and consumed-fuel with the error less than 3%, and heat and power efficiency with the error less than 4%. The CogenSim-$\mu$ reconstructed the profile of on-off cycle, which represented the operation of a facility, with more than 93% accuracy. The CogenSim-$\mu$ can reflect the effects of various factors such as size of thermal storage tank, desired temperature of reservoir water, natural frequency of generator, etc. As a result, the CogenSim-$\mu$ can be used to optimize the ${\mu}CHP$ operation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.1
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• pp.15-20
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• 2014

In this study, improvement of university education is suggested so that university graduates in Architectural Engineering can work in the plant engineering industry without major retraining, which is generally required by plant engineering companies. Before the disposition of manpower to a plant engineering site, new recruits are retrained for about 2~3 years, since university education is neither sufficient, nor appropriate to handle plant engineering tasks. It is necessary to implement practical plant engineering into university education, so that graduates can work effectively in plant engineering fields, without major retraining. For a case study of an S2 University located in Seoul, it is enough to supplement the interdisciplinary program with plant engineering subjects, if proper texts are developed. To replace the plant engineering education offered by the company with university education, the following measures should be taken. First, basic plant engineering should be taught for 15 hours. Second, education on design and drawings should be reinforced.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.3
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• pp.566-573
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• 2016

Sustainability in fashion cannot ignore fashion attributes required for the design of rapidly changing and innovative products. This study examines "Re-Birth Design" development and provides a means to apply academic and industry perspectives to the investigation of Re-Birth fashion product development. This study defines "Re-Birth Design" as stock that has been designed and launched through distribution channels, subsequently returned unused, then improved and reborn into a new product for redistribution. This study analyzed specific cases. We selected 100 designs for Re-Birth from 11 brands of "K" fashion company in Korea, to be successfully sold in 2014. These cases are used in the analysis and are categorized into design types. As a result of the analysis, "Re-Birth Design" had five levels: Level 1. Changes in supplementary materials such as adding or removing decoration, Level 2. Changes in patterns or materials (changes within the product), Level 3. Partial changes in design (leading to a new design), Level 4. Complete deconstruction and rebirth of the design, and Level 5. Complete deconstruction followed by the use of the design source for a new product that is not a garment. This study analyzed products owned by brands, as well as successful cases of Re-Birth designs that reused existing resources, reduced energy consumption, and increased environmental and economic efficiency by recreating new products that could be resold.

• IE interfaces
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• v.22 no.3
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• pp.243-251
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• 2009

The driving force of the manufacturing field is members' mind-set and activity. However, there is no appropriate program of change management for workers who work in the manufacturing field. Most of the small group activities were focused on the fixed tools and processes to make improvement only, not the change itself. Therefore, it was difficult to have self generating energy without actually motivating people of change. Study of IFI(Integrated Field Innovation) means change of management. This study will introduces IFI which is a new methodology of change and innovation of workers, and will describe how workers participated in the activities voluntarily. The principle of IFI is that letting employees to find the problems of the sites -anything that makes employees considering as the problem while they are working- and solve those problems through any tools own their own. Workers do not have to waste their time on bounding by unnecessary tools and processes. There are several cases that company "D" has been actually applied the IFI methodology in 2008. Through these cases, IFI proved that it was a optimized methodology for workers who work in the manufacturing field.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.2
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• pp.112-118
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• 2018

In recent years, decentralized power have been increasing due to environmental problems, liberalization of electricity markets and technological developments. These changes have led to the evolution of power generation, transmission, and distribution into discrete sectors and the division of integrated power systems. Therefore, studies are underway to efficiently supply power and reduce losses to each sector's demand. This is a major concern for system planners and operators, as it accounts for a relatively high proportion of total power, with a transmission and distribution loss of 4-6%. Therefore, this paper analyzes the status of loss management based on the current transmission and distribution loss rate of each country and transmission loss management cases of each national power company, and proposes a loss rate prediction algorithm according to the long-term transmission system plan. The proposed algorithm predicts the demand-based long-term evolution and the loss rate of the grid to which the transmission plan is applied.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.89-112
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• 2017

Dyeing wastewaters are the most problematic wastewater in textile industries and also, growing amounts of waste fibers in carpet industries have concerned environmental specialists. Among different treatment methods, membrane filtration processes as energy-efficient and compatible way, were utilized for several individual problems. In this research, novel hybrid membranes were prepared by waste fibers of mechanical carpets as useful resource of membrane matrix and industrial graphite powder as filler to eliminate Chrysophenine GX from dyeing wastewater. These membranes were expected to be utilized for first stage of hybrid membrane filtration process including (adsorption-ultrafiltration) and nanofiltration in Kashan Textile Company. For scaling of membrane filtration process, fouling mechanism of these membranes were recognized and explained by the use of genetic algorithm, as well. The graphite increased rejection and diminished permeate flux at low concentration but in high concentration, the performance was significantly worsened. Among all hybrid membranes, 18% wt. waste fibers-1% wt. graphite membrane had the best performance and minimum fouling. The maximum pore size of this optimum membrane was ranged from 16.10 to 18.72 nm.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1225-1231
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• 2014

This paper presents the performance characteristic of a Francis hydro turbine with an inline casing. This turbine is designed for city water supply system. Due to large changes in ground elevation with high points and low points, some systems may experience larger-than-normal required pressures in areas with low ground elevations. One way to dissipate these excess pressures is by the use of an inline-turbine instead of an inline-pressure reducing valve. For best applicability and minimal space consumption, the turbine is designed with an inline casing instead of the common spiral casing. As a characteristic of inline casing, the flow accesses to the runner in the radial direction, showing a low efficiency. The installation of vanes improves the internal flow and gives the positive encouragement to the output power. For the power transmission to the outside of the turbine casing from the runner axis, a belt passage is designed in the inline casing, as its influence, the region after the belt passage shows a relatively low output power. The clearance gap in the runner side space is considered, in which a small volume of flow is contracted into the clearance gap, forming the leakage flow. The leakage flow leads to a decrease in the efficiency.

• Journal of Distribution Science
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• v.12 no.3
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• pp.75-83
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• 2014

Purpose - The oil price affects company value, which is the present value of the expected cash flow, by affecting the discount rate and cash flow. This study examines the nonlinear relationships between oil price and stock price using the AlphaShares Chinese Volatility Index as the threshold. Research design, data, and methodology - Data comprise daily closing values of the Shanghai Stock Exchange Composite Index, Shenzhen Stock Exchange Composite Index, and Hang Seng Index of ChinaWest Texas Intermediate crude oil spot price and AlphaShares Chinese Volatility Index from May 25, 2007 to May 24, 2012. The Threshold Error Correction Model is used. Results - The results demonstrate different relationships between the stock price index and oil price under different investor sentiments; however, the stock price index and oil price could adjust to a long-term equilibrium the long-term causality tests between them were all significant. Conclusions - The relationship between the WTI and HANG SENG Index is more significant than the Shanghai Composites Index and Shenzhen Composite Index, when using the AlphaShares Chinese Volatility Index (ASC-VIX) as the investor sentiment variable and threshold.

• Korean Journal of Computational Design and Engineering
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• v.21 no.3
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• pp.281-295
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• 2016

Lately, the management of domestic BIM performance is quite lacking, as the evaluation and management data from successful cases of BIM implementation both on projects and in companies, and related effects (time, cost and other physical gains) are not well kept for future use in BIM development. In order to overcome the above obstacles, a systematic approach to evaluating BIM adoption with focus on particular elements like BIM implementation environment and processes, and the physical factors yielded by BIM, is necessary. In this study, objective and detailed assessment indicators and weights that are appropriate for the domestic situation were derived through research for purposes of developing a web-based BIM maturity measurement program that is tailor-made for the Korean construction atmosphere. Through a company's self-maturity measurement, excellent quality of BIM deliverables and output can be achieved and managed. Furthermore, the domestic BIM capacity can gradually increase since design firms' BIM capability can be judged during procurement basing on measurement indicators.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.563-566
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• 2002

We investigated to decrease the leakage current of SiNx film by employing $N_2$ plasma treatment. The insulator layers were prepared by two step process; the $N_2$ plasma treatment and then PECVD SiNx deposition with $SiH_4$, $N_2$ gases. To prove the influence of the $N_2$ plasma treatment, the Si substrate was exposed to the plasma, which was generated in Ne gas ambient. Without plasma treatment SiNx film grow at the rate of 7. 03 nm/min, has a refractive index n = 1.77 and hydrogen content of $2.16{\times}10^{22}cm^{-3}$ for $N_2/SiH_4$ gas flow ratio of 20. The obtained films were analyzed in terms of deposition rates, refractive index, hydrogen concentration, and electrical properties. By employing $N_2$ plasma treatment, interface traps such as mobile charges and injected charges were removed, hysteresis of capacitance-voltage (C-V) disappeared. We observed plasma treated sample were decreased the leakage current density reduces by 2 orders with respect to the sample having no plasma treatment.