• Resources Recycling
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• v.19 no.3
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• pp.24-32
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• 2010

In the present work, a new separation system with rotating rakes has been developed to separate the film-based plastics from the recyclable materials, and environment assessment is also carried out during operation of the device. Capacity of the device was about 5.3 ton/hr at a rakes rotation speed of 26.0 rpm (the number of rakes in the 1st, 2nd and 3rd trials were 39, 52 and 48, respectively) and a belt conveyor speed of 38.5m/min, which satisfied the initial design capacity (5.0 ton/hr). Recovery ratio and purity of the plastic films were 92.6% and 96.5%, respectively at a rotation speed of 28 rpm. The levels of noise, vibration and particulate emission were below material standard regulatory limits. Plastic refused fuel (RPF) was also prepared with the recovered films. The calorific value and chlorine content of the prepared RPF were 9,740 kcal/kg and 0.18%, respectively which satisfy the first grade quality specification of the Korean RPF standard. As a result of this work, recovery of energy resources from the municipal solid waste is possible by adopting the developed separation device.

• Resources Recycling
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• v.15 no.1 s.69
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• pp.37-45
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• 2006

For treating a huge amount of plastic waste with the environment problem, pyrolysis of plastic waste into alternative fuel oil is one or important issue in recycling methods. This study was introduced over the trend or generation of plastic waste, in Korea pyrolysis technology in domestic and foreign countries, basic technology in pyrolysis process and new technology of pyrolysis developed in KIER (Korea Institute of Energy research). The characteristics of process developed in KIER are the continuous loading treatment or mixed plastic waste with an automatic control system, the minimization of wax production by circulation pyrolysis system in non-catalytic reactor, the reuse of gas produced and the oil recovery from sludge generated in pyrolysis plant, which have greatly the advantage economically and environmetally. The experiment result data in 300 ton/yr pilot plant showed about $81\;wt\%$ liquid yield for 3 days continuous reaction time, and also the boiling point distribution of light oil (LO) and heavy oil (HO) produced in distillation tower was a little higher than that of commercial gasoline and diesel, respectively.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.293-305
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• 2009

Methane, as a greenhouse gas, is some 21~25 times more detrimental to the environmental than carbon dioxide. Landfills generally constitute the most important anthropogenic source, and methane emission from landfill was estimated as 35~73 Tg per year. Biological approaches using biocover (open system) and biofilter (closed system) can be a promising solution for older and/or smaller landfills where the methane production is too low for energy recovery or flaring and installation of a gas extraction system is inefficient. Methanotrophic bacteria, utilizing methane as a sole carbon and energy source, are responsible for the aerobic degradation (oxidation) of methane in the biological systems. Many bench-scale studies have demonstrated a high oxidation capacity in diverse filter bed materials such as soil, compost, earthworm cast and etc. Compost had been most often employed in the biological systems, and the methane oxidation rates in compost biocovers/boifilters ranged from 50 to $700\;g-CH_4\;m^{-2}\;d^{-1}$. Some preliminary field trials have showed the suitability of biocovers/biofilters for practical application and their satisfactory performance in mitigation methane emissions. Since the reduction of landfill methane emissions has been linked to carbon credits and trading schemes, the verified quantification of mitigated emissions through biocovers/biofilters is very important. Therefore, the assessment of in situ biocovers/biofilters performance should be standardized, and the reliable quantification methods of methane reduction is necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.1005-1012
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• 2011

This research carried out a 3-dimensional simulation using computerized fluid dynamics (CFD) for the flow characteristics, temperature distribution, velocity distribution and residence time, etc. in a reactor in order to derive the optimal combustion conditions of an innovative combustion system. The area-weighted average temperature of the outlet of a furnace during combustion at a condition of fuel input rate 1.5 ton/hr, residence time 1.25 sec and air/fuel ratio 2.1 was $1,077^{\circ}C$, which is a suitable temperature for energy recovery and treatment of air pollutants. Exhaust gas is discharged through a duct at a 40~50 m/s maximum speed along strong vortexes at the center of a combustion chamber, so strong turbulence is created at the center of a combustion chamber to enhance the combustion speed and combustion efficiency. In this system, the optimum operation conditions to prevent incomplete combustion and suppress the formation of thermal NOx were air/fuel ratio 1.9~2.1 and fuel input rate 1.25~1.5 ton/hr.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.11
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• pp.589-595
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• 2016

This study evaluated the environmental impacts for landfill treatment of the wastewater treatment sludge (WTS) from petrochemical firms by life cycle assessment (LCA) and reviewed the impact reduction by landfill gas (LFG) utilization. The functional unit was 'landfill of 1 ton of WTS', and the system boundary included the process of input and treatment for WTS in landfill site. The impacts were high at landfill process (LP) and leachate treatment process (LTP). Global warming (GWP) and photochemical oxidants creation (POCP) were high at LP, while abiotic depletion (ADP), acidification (AP), eutrophication (EP), ozone depletion (ODP) were high at LTP. The major substances of various impact categories were crude oil (ADP), $NO_X$ (AP, EP), $CH_4$ (GWP, POCP), $Cl_2$ (ODP), respectively. The major factor of ADP, AP, EP was attributed from the generation of electricity used in LTP, and the methane within uncollected LFG was main factor of GWP and POCP. Therefore, electricity consumption reduction is identified to be an impact improvement option, and the flaring system installation or enhanced LFG recovery could be an alternative to reduce impacts. Among the various categories, GWP accounted the highest impact (${\geq}90%$) followed by ADP, POCP. In the avoidance impact resulted from the utilization of LFG, to substitute B-C oil or LNG showed the impact reduction of 32.7% and 12.0%, respectively.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.34-46
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• 2005

For treating a huge amount of plastic waste with the environment problem, pyrolysis of plastic waste into alternative fuel oil is one of important issue in recycling methods. This study was introduced over the trend of generation of plastic waste, pyrolysis technology in domestic and foreign countries, basic technology in pyrolysis process and new technology of pyrolysis developed in KIER (Korea Institute of Energy Research). The characteristics of process developed in KIER are the continuous loading treatment of mixed plastic waste with an automatic control system, the minimization of wax production by circulation pyrolysis system in non-catalytic reactor, the reuse of gas produced and the oil recovery from sludge generated in pyrolysis plant, which have greatly the advantage economically and environmetally. The experiment result data in 300 ton/yr pilot plant showed about 81 wt% liquid yield for 3 days continuous reaction time, and also the boiling point distribution of light oil (LO) and heavy oil (HO) produced in distillation tower was a little higher than that of commercial gasoline and diesel, respectively.

• Applied Biological Chemistry
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• v.27 no.3
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• pp.180-186
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• 1984

For the study of glucose oxidase(GOD) and catalase(CAT) coimmobilization system, the enzymes were obtained from Penicillium spp., PS-8, and the strain itself was used as an immobilizing matrix. To separate glucose oxidase and catalase after the ammonium sulfate fractionation of the culture broth, DEAF-cellulose column was used and its activity yield was 54 and 34%, respectively. Both enzymes were immobilized on the cell matrix, followed crosslinking with 2.5% glutaraldehyde for 12hr. In the determination of efficiencies of GOD and CAT of dual, mixed and soluble enzyme systems, the dual immobilized one w-as superior to those of the soluble or mixed ones. In the comparison of pH profiles, the dual and mixed types showed broader maximum pH ranges than the soluble type. Varying CAT/GOD ratio of the dual system, the higher the ratio showed the broader activity profile. In the comparison of apparent $K_m$ of GOD only and CAT/GOD=10, they were $7.1{\times}10^{-2}$ and $5.1{\times}10^{-2}M$. Their activation energies showed 3.98kcal/mole/deg for GOD only and 2.98kcal/mole/deg for CAT/GOD=10.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.250-255
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• 2011

In this study, by using the polymeric membrane separation process, the $CO_{2}/CH_{4}$ separation and $H_{2}S$ removal from biogas were performed in order to $CH_{4}$ purification and enrichment for the fuel cell energy source application. Fibers were spun by dry/wet phase inversion method. The module was manufactured by fabricating fibers after surface coating with silicone elastomer. The scanning electron microscopy(SEM) studies showed that the produced fibers typically had an asymmetric structure; a dense top layer supported by a porous, sponge substructure. The permeance of $CO_{2}$ and $CO_{2}/CH_{4}$ selectivity increased with pressure and temperature. Mixture gas with increasing pressure and temperature, removal efficiency of the $CO_{2}$ and $H_{2}S$ were decreased while concentration of $CH_{4}$ was increased up to 100%. When retentate flow rate was increased with the decreasing of pressure and temperature the $CH_{4}$ recovery ratio in retentate side was increased while the $CH_{4}$ purity in retentate side was decreased.

• The Journal of Bigdata
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• v.4 no.1
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• pp.63-72
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• 2019

For power energy, optimal generation and distribution plans based on accurate demand forecasts are necessary because it is not recoverable after they have been delivered to users through power generation and transmission processes. Failure to predict power demand can cause various social and economic problems, such as a massive power outage in September 2011. In previous studies on forecasting power demand, ARIMA, neural network models, and other methods were developed. However, limitations such as the use of the national average ambient air temperature and the application of uniform criteria to distinguish seasonality are causing distortion of data or performance degradation of the predictive model. In order to improve the performance of the power demand prediction model, we divided Korea into five major regions, and the power demand prediction model of the linear regression model and the neural network model were developed, reflecting seasonal characteristics through regional characteristics and migration period learning techniques. With the proposed approach, it seems possible to forecast the future demand in short term as well as in long term. Also, it is possible to consider various events and exceptional cases during a certain period.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.608-611
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• 2003

선진국입을 목전에 둔 한국경제의 발전을 위해서 지식과 기술을 기반으로 한 벤처기업의 생성과 발전은 매우 중요한 요소라 할 수 있다. 민과 관의 적절한 벤처 투자는 미래의 기업가들에게 신지식 창조의 동기를 부여하고 성장, 발전단계에 있는 기업들에게 자본을 공급함으로써 미래의 산업을 창조하는 매우 중요한 활동이다. 국내외적으로 벤처 투자자본에 대한 연구가 활발히 진행되어 왔으나 재무론을 바탕으로 한 벤처투자에 관한 연구와 다양한 벤처투자자본들의 유형과 투자행태 등을 설문지를 통해 밝혀내는 탐색적 연구들에 국한되어 연구, 발표되고 있는 실정이다. 본 연구에서는 벤처자본시장의 대표적 투자자본인 사적 창업투자회사와 정부 벤처정책투자 간의 전략적 상호작용을 가격모델을 통해 고찰하였다. Bertrand paradox의 가정에서 기술한 바와 같이 정부 벤처정책투자간 민간 창업투자회사들과 같은 투자전략을 구사하면 민간 창업투자회사들은 시장에서 살아남기 어렵고 결과적으로 정부는 벤처기업의 생성 및 발전지원이라는 목적에 부합되지 않은 투자를 한 것이 된다. Hotelling(1929)의 위치차별모델이 역설하는 바와 같이 정부 벤처정책투자는 사적 창업투자회사가 지향하는 투자와는 다른 투자정책을 구사할 때만 벤처기업 육성이라는 목표를 효율적으로 수행할 수가 있을 것이다. 이 연구 논문에서는 다양한 투자변수에 대한 Nash Equibrium이 존재함을 증명함으로써 사적 창업투자회사와 정부의 벤처정책투자가 벤처기업의 육성이라는 목적에 맞는 효율적 투자를 하기 위해 취해야 할 투자 전략들을 밝혀내었다.가 있는 것 같다. 따라서 본 연구에서는 웹기반 쇼핑시스템의 확산에 관련된 균형된 분석을 수행하기 위하여 경영(management)과 기술 (technology)을 조화롭게 고려한 관점에서 연구를 수행하고자 한다. 즉, 본 논문에서는 기술적 측면(technical aspect)과 경영적 측면(management aspect)을 동시에 고려하여 웹기반 쇼핑시스템의 주요만 특성을 살펴보고, 향후 정보통신 기술(ICT)의 확산에 관한 연구에서 두 가지 관점의 통합적 중요성에 대하여 강조하고자 한다. 그에 덧붙여 웹기반 쇼핑시스템과 다른 정보시스템을 비교하여 전자상거래 환경에서 웹기반 쇼핑시스템의 주요만 특성들이 두가지 연구관점에서 어떻게 개념화 될 수 있는지를 고찰하고자 한다. 이러만 분석에 기반하여 본 연구에서는 기술적 측면과 경영적인 측면을 동시에 고려한 웹기반 쇼핑시스템의 특성을 제시하고자 한다. 결론적으로 본 연구의 목적은 본 논문에서 적용한 기술(technical)과 경영(management)의 조화로운 연구관점이 향후 정보통신 기술이나 시스템, 그리고 전자상거래에 관련된 일련의 연구에 적응되어 보다 균형잡힌 논의와 분석이 이루어 질 수 있는 시발점이 되길 기대한다.생된 $CH_{4}$를 회수하여 이용하면 대체에너지원으로 활용 가치가 높은 것으로 판단된다./207), $99.2\%$(238/240), $98.5\%$(133/135) 및 $100\%$ (313)였다. 각각 두 개의 요골동맥과 우내흉동맥에서 부