• Industrial Engineering and Management Systems
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• v.6 no.1
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• pp.22-27
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• 2007

This paper describes the optimization of maintenance workforce scheduling at Afam power station in Nigeria. The objective is to determine the optimum schedule to satisfy growing maintenance labour requirements with minimum cost and highest efficiency. Three alternative maintenance workforce schedules are compared. The first alternative is to continue with the traditional five-day workweek schedule currently being practiced by Afam power station maintenance line. The second alternative is to switch to a seven-day workweek schedule for the morning shift only. The third alternative is to use a seven-day workweek schedule for all three work shifts. The third alternative is chosen, as it is expected to save 11% of the maintenance labour cost.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.57-63
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• 2011

Development of alternative energy is needed as the fossil is started to be exhausted. This alternative energy should be environmental friendly and renewable. Currently, the alternative energy which gets the most attraction is hydrogen. Hydrogen can be produced by a number of different processes. Among those methods, hydrogen production in biological way is considered as the most environmental friendly method. However, productivity of biological hydrogen production is not good enough to be commercialized yet. Thus, many researchers are trying to improve productivity and yield of biohydrogen production. Here, progress in the diverse developmental approaches on biological hydrogen production, is reviewed.

• Molecules and Cells
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• v.37 no.1
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• pp.81-87
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• 2014

Chronic pressure-overload cardiac hypertrophy is associated with an increased risk of morbidity/mortality, largely due to maladaptive remodeling and dilatation that progresses to dilated cardiomyopathy. Alternative splicing is an important biological mechanism that generates proteomic complexity and diversity. The recent development of next-generation RNA sequencing has improved our understanding of the qualitative signatures associated with alternative splicing in various biological conditions. However, the role of alternative splicing in cardiac hypertrophy is yet unknown. The present study employed RNA-Seq and a bioinformatic approach to detect the RNA splicing regulatory elements involved in alternative splicing during pressure-overload cardiac hypertrophy. We found GC-rich exonic motifs that regulate intron retention in 5' UTRs and AT-rich exonic motifs that are involved in exclusion of the AT-rich elements that cause mRNA instability in 3' UTRs. We also identified motifs in the intronic regions involved in exon exclusion and inclusion, which predicted splicing factors that bind to these motifs. We found, through Western blotting, that the expression levels of three splicing factors, ESRP1, PTB and SF2/ASF, were significantly altered during cardiac hypertrophy. Collectively, the present results suggest that chronic pressure-overload hypertrophy is closely associated with distinct alternative splicing due to altered expression of splicing factors.

• Proceedings of the Technology Innovation Conference
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• 2006.02a
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• pp.264-297
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• 2006

In this paper, we attempt to analyze consumer preference for the alternative-fuel vehicles based on data from a stated preference using the conjoint analysis. Five possible fuel types (gasoline, diesel, CNG, LPG, Hybrid (electricity+gasoline)) are covered in conjoint cards. To estimate and analyze consumer preference, discrete choice model is used. Specifically, Bayesian mixed logit model is used. Based on estimating results, we discuss the business strategy and policy for the alternative fuel vehicle.

• Environmental Engineering Research
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• v.18 no.3
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• pp.145-150
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• 2013

Optimal preparation guidelines of a cathode catalyst layer by non-precious metal catalysts were evaluated based on electrochemical performance in single-chamber microbial fuel cells (MFCs). Experiments for catalyst loading rate revealed that iron(II) phthalocyanine (FePc) can be a promising alternative, comparable to platinum (Pt) and cobalt tetramethoxyphenylporphyrin (CoTMPP), including effects of substrate concentration. Results showed that using an optimal FePc loading of $1mg/cm^2$ was equivalent to a Pt loading of $0.35mg/cm^2$ on the basis of maximum power density. Given higher loading rates or substrate concentrations, FePc proved to be a better alternative for Pt than CoTMPP. Under the optimal loading rate, it was further revealed that 40 wt% of FePc to carbon support allowed for the best power generation. These results suggest that proper control of the non-precious metal catalyst layer and substrate concentration are highly interrelated, and reveal how those combinations promote the economic power generation of single-chamber MFCs.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.73-79
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• 2011

In this paper, cycle performance analysis of cascade refrigeration system using alternative FREON refrigerants are presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooled and superheated degree, and evaporating and condensing temperature, temperature difference of cascade heat exchanger in cascade refrigeration system. The COP of cascade refrigeration system increases with the increasing subcooled degree, but there is no significant changes with the increasing superheated degree. The COP of cascade refrigeration system depends on evaporating and condensing temperatures of cascade heat exchanger. Therefore, subcooled degree, evaporating and condensing temperature of cascade heat exchanger using alternative FREON refrigerants have an effect on the COP of this system. In this paper, COP of cascade refrigeration system using R23 for low temperature system and R507A for high temperature system is higher 8 ~ 29 % than using R13 for low temperature system and R22 for high temperature system.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.965-970
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• 2008

The separation of sulfone components using light cycle oil(LCO) after oxidation was carried out by solvent extraction method using various polar solvents such as water, n-methyl-2-pyrrolidone(NMP), dimethyl sulfoxide, ethyl acetate, acetonitrile, dimethyl formamide, and methyl alcohol. It was found that phase separation between LCO layer and solvent occurred under mixed solvent adding a proper amount of water. The mixture solvent of NMP and water was a promising extraction solvent due to the selective removal and high distribution coefficient of sulfone component in LCO. 99.5% over of sulfur contents in LCO can be removed by 4 stages equilibrium extraction.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.111-121
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• 2005

The Seoul Housing Corporation pronounced an alternative design competition and a bidding for Eunpyeong New Town in December of 2004. At first many construction companies were interested in the first New Town Project. But at last a few companies had proposed the alternative design and construction cost. This project needed a conjunction of design ideas and technology know-hows. And the client wanted the brand power of construction company. Ultimately the Corporation hoped that the first New Town Project will end up with high quality successfully. This competition had started with the original construction drawings. Then it needed some alternative ideas and the lowest cost. There were two drawings of non changeable part and changeable part. Non changeable parts are structure like housing unit plan, underground parking lots. Changeable parts are outdoor layout, interior design and building facade. So we tried all ideas of landscape technology and design principles within limited guidelines. The author applied new technology like tilted rooftop greening and sustained container greening on high-rise apartment house. This green technology will be the first trial in Seoul and in the world as well. Daewoo Corporation have accumulated greening technology through the researches by national funding since 2002. Through this New Town Project the green technology will go forward step by step.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.1
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• pp.42-51
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• 2010

The semiconductor industry is highly capital and technology intensive. Technology advancement on circuit design and process improvement requires chip makers continuously to invest a new fabrication facility that costs more than 3 billion US dollars. Especially major semiconductor companies recently started to discuss 450mm fabrication substituting existing 300mm fabrication of which facilities were initiated to build in 1998. If the plan is consolidated, the yield of 450mm facility would be more than doubled compared to existing 300mm facility. In steps of this important investment, facility layout has been acknowledged as one of the most important factors to be competitive in the market. This research proposes a new concept of semiconductor facility layout using hexagonal floor plan and its compatible material flow pattern. The main objective of this proposal is to improve the productivity of the unified layout that has been popularly used to build existing facilities. In this research, practical characteristics of the semiconductor fabrication are taken into account to develop a new layout alternative based on the analysis of Chung and Tanchoco (2009). The performance of the proposed layout alternative is analyzed using computer simulation and the results show that the new layout alternative outperforms the existing layout alternative, unified layout. However, a few questions on space efficiency to the new alternative were raised in communication with industry practitioners. These questions are left for a future study.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.5
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• pp.69-79
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• 2019

The purpose of this study is to suggest a guideline that can be used as a standard for consultation and review by environmental impact assessment consultation and review practitioner to enhance the practical effectiveness of creating alternative habitats. The consultation stage of environmental impact assessment was significantly divided into 1) preparation of draft environmental impact assessment reports and gathering of consensus thereon, 2) preparation of environmental impact assessment reports and consultation thereon, 3) follow-up survey of environmental impacts(under construction) and 4) follow-up survey of environmental impacts(in operation). And it was suggested that the procedures of creating alternative habitat by each consultation stage were linked in order of 1) planning, 2) designing, 3) construction, and 4) post-monitoring and maintenance. The basic principles were also proposed for each stage of consultation on environmental impact assessment and procedure for the creation of alternate habitats. Then, issues and methods to be reviewed by the consulting agency and review agency of environmental impact assessment were presented in detail. The guideline of this study provides important information not only to environmental impact assessment consultation and review practitioner, but also to developers and environmental impact assessment agents who plan, construct, and manage alternative habitats.