• 국제학술발표논문집
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• The 10th International Conference on Construction Engineering and Project Management
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• pp.25-32
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• 2024

Conventional construction methods face significant challenges in reducing carbon emissions and promoting environmental sustainability. Off-Site Construction (OSC) method is widely recognized as a low-carbon, high-efficiency alternative construction method. However, in practice, it often fails to deliver the expected benefits, leading to issues such as excessive carbon emissions, unpunctual delivery, and cost overruns in OSC projects. In order to ensure the carbon benefits of OSC and further its development,this study conducts an in-depth analysis of embodied carbon emissions in the precast production process, proposes a multi-objective optimization model based on the permutation flow shop scheduling problem, and designs an automated solution algorithm using NSGA-II to derive Pareto optimal schedules. Through the analysis of real-world case data, the proposed approach, compared to conventional scheduling methods, is estimated to reduce embodied carbon emissions by approximately 6 % while simultaneously cutting tardiness/earliness penalty by 75%. This study offers a model for precast production scheduling, effectively enhancing production efficiency and reducing carbon emissions, enabling construction component enterprises to engage in low-carbon, cost-effective, and efficient production, thereby fostering sustainable development in the construction industry.

• 대한안전경영과학회지
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• 제4권4호
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• pp.73-85
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• 2002

The supply chain not only includes the manufacturer and suppliers, but also transporters, warehouses, retailers, and customers themselves. Within each organization, such as manufacturer, the supply chain includes all functions involved in filling a customer request. these functions include, but are not limited to, new product development, marketing, operation, distribution, finance, and customer service. Lean Supply chain coordination improves if all supplier of chain take actions that together increase total supply chain profits. To design of Modularity by the grouping supplier, the proposed method is to develop the most appropriate production system models in the Supply Chain Management which is necessity of the times and its importance. The objects of this study is development of model and cost analysis to the modular production system in Lean SCM. Introduction of modular production system in Lean SCM is effective in reducing the cost in processing, manufacturing, inventory holding, ordering, etc.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.946-950
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• 2014

Bacillus licheniformis was grown in minimal nutrient medium containing 1% (w/v) of distillers dried grain with soluble (DDGS), palm kernel meal (PKM), wheat bran (WB) or copra meal (CM), and the enzyme activity of endoglucanase, ${\beta}$-glucosidase, xylanase and reducing sugars was measured to investigate a possibility of using cost-effective agricultural residues in producing cellulolytic and hemicellulolytic enzymes. The CM gave the highest endoglucanase activity of 0.68 units/mL among added substrates at 48 h. CM yielded the highest titres of 0.58 units/ml of ${\beta}$-glucosidase, compared to 0.33, 0.23, and 0.16 units/mL by PKM, WB, and DDGS, respectively, at 72 h. Xylanase production was the highest (0.34 units/mL) when CM was added. The supernatant from fermentation of CM had the highest reducing sugars than other additional substrates at all intervals (0.10, 0.12, 0.10, and 0.11 mg/mL respectively). It is concluded that Bacillus licheniformis is capable of producing multiple cellulo- and hemicellololytic enzymes for bioethanol production using cost-effective agricultural residues, especially CM, as a sole nutrient source.

• 신재생에너지
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• 제7권3호
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• pp.6-16
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• 2011

In order to study the utilization of seaweeds as an alternative renewable feedstock for bioethanol production, their properties of hydrolysis and fermentation were investigated. The seaweeds were well hydrolyzed with diluted sulfuric acid. The weight loss of seaweeds reached 75-90%, but only 12-51% of them was converted into reducing sugars after the acid-hydrolysis at $130^{\circ}C$ for 4-6h. The yield of reducing sugars increased with increasing the hydrolysis time up to 4h and then decreased thereafter. In contrast, the ethanol yield from the hydrolysates increased with hydrolysis time except for green seaweeds maximizing at 4h. Optimal fermentation time by Saccharomyces cerevisiae (ATCC 24858) varied with seaweeds; 48h for green seaweeds, 96h for brown and red seaweeds. The ethanol yield from the hydrolysate reached 138${\pm}$37mg/g-dry for green seaweeds, 258${\pm}$29mg/g-dry for brown seaweeds, and 343${\pm}$53mg/g-dry for red seaweeds, which correspond to approximately 1.5-4.0 times more than the theoretical yield from total reducing sugars in the hydrolysates. The results obtained indicate clearly that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. Considering the productivity and production cost of each seaweed, brown seaweeds such as Laminaria japonica and Undaria pinnatifida seem to be a promissing feedstock for bioethanol production.

• 한국유기농업학회지
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• 제22권1호
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• pp.155-166
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• 2014

Organic forage production system is one of the most important aspects in organic livestock production. Animals in the organic farming system are also essential for manure to be used for organic forage production. Both organic forage and animals are essential to maintain the cycle of organic agriculture system. In this paper we introduce the organic forage production system in Korea. Summer and winter crops are getting popular in Korea because of their high forage yield and cultivation in double cropping systems. Common cropping system for forage production in Korea is the double cropping system with legume and grass mixture. Forage sorghum and sudangrass are the most popular ones of annual summer forage corps because of their high production with low cost in the double cropping systems. In the mixture of forage crops, inter cropping is more suitable in the corn and sorghum cropping system because of high lodging resistance and forage yield, and low weed population. Forage sorghum and sudangrass are difficult to preserve as direct-cut silage due to the fact that its high moisture content causes excessive fermentation during ensiling. Corn grain addition to sorghum silage could be recommended as the most effective treatment for increasing quality and reducing production cost. It is recommended that corn grain could be added up to 10% of total amount of silage. And agriculture by-products also can be added at the time of ensiling to minimize losses of effluent and have the additional advantage of increasing quality. Agriculture by-products as silage supplements increased DM content and quality, and decreased the production cost of sorghum silage. Field pre-wilting treatment of forage crops also increased DM content and quality of the silage. Wilting sorghum${\times}$sudangrass hybrid before ensiling was the effective method for reducing effluent and increasing pH and forage quality more than direct cut silage. Optimum prewilting period of sudangrass silage was 1 or 2 days. In organic forage, the most important factor is the enhancement of organic forage sufficiency in relation to the environmental-friendly and organic livestock. Consequently, there are many possibilities for animal production and organic forage production in Korea. No forages no cattle concept should be emphasized in organic farming system.

• 펄프종이기술
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• 제42권5호
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• pp.1-14
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• 2010

Bio-ethanol is a promising alternative energy source for reducing both consumption of crude oil and environmental pollution from renewable resources like lignocellulosic biomass such as wood, forest residuals, agricultural leftovers and urban wastes. Based on current technologies, the cost of ethanol production from lignocellulosic materials is relatively high, and the main challenges are the low yield and high cost of the hydrolysis process. Development of more efficient pretreatment technology (physical, chemical, physico-chemical, and biological pretreatment), integration of several microbiological conversions into fewer reactors, and increasing ethanol production capacity may decrease specific investment for ethanol producing plants. The purpose of pretreatment of lignocellulosic material is to improve the accessible surface area of cellulose for hydrolytic enzymes and enhance the conversion of cellulose to glucose and finally high yield ethanol production which is economic and environmental friendly.

• Journal of Magnetics
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• 제22권1호
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• pp.14-22
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• 2017

The NMR's probe consists of the static magnetic field generator (magnetic source) and the RF coil. It is very strict for the homogeneity of the static magnetic field intensity of the magnetic source, so the cost of the magnetic source is more expensive in the entire nuclear magnetic resonance instrument. The magnetic source generally consists of electromagnet, permanent magnet and superconducting magnet. The permanent magnet basically needs not to spend on operation and maintenance and its cost of manufacture is much cheaper than the superconducting magnet. Therefore, the permanent magnet may be the only choice for the static magnetic field device if we want to use the magnetic resonance instrument as an analyzer for production by reducing price. A new probe magnet was developed on the basis of the permanent magnet ring in this paper to provide a technological way for reducing the manufacturing cost, weight and volume of the existing nuclear magnetic resonance instrument (including MRI) probe.

• 청정기술
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• 제2권1호
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• pp.1-6
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• 1996

Cleaner production is of substantial importance in changing the environmental approach within advanced industrialized countries. The critical principles involve fundamental understanding of diverse industrial processes, adherence to the earliest techniques of a hierarchy for reducing wastes, and utilization of an underlying thought process to achieve pollution prevention successes that are both technically feasible and cost-effective. Chemical engineering has played a major and unique role in this environmental field. Improving the sustainability of cleaner production will rest on including this subject in the curriculum of university engineering.

• 대한안전경영과학회지
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• 제2권2호
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• pp.139-153
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• 2000

To develope a domestic machinery industry, international competition through reducing cost by increasing productivity is as important as evolving technology and increasing quality. In this study, we have studied in application of GT technology. GT is a skill that acquires high productivity using part's resemblance for multi part and small size production like mass production. We have classified group, such as design, layout and the others, to be applied systematically. The design group includes retrieval for drawings and study for GT design. The layout group includes GT layout, analysis of production process and study for composition method. And others include scheduling, standardization and standard process.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.48-53
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• 2012

Due to the customer needs of reducing cost and delivery date shorting, prompt change in the production plan became more important. In the multi period system (For instance, production line.) where target processing time exists, production, idle and delay risks occur repeatedly for multiple periods. In such situations, delay of one process may influence the delivery date of an entire process. In this paper, we discuss the minimum expected cost of the case mentioned above, where the risk depends on the previous situation and occurs repeatedly for multiple periods. This paper considers the optimal switching frequency to minimize the total expected cost of the production process. In this paper, first, the optimal switching frequency model is proposed. Next, the mathematic formulation of the total expectation is presented. Finally, the policy of optimal switching frequency is investigated by numerical experiments.