• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.251-251
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• 2011

해양 투기가 금지되면서 혐기소화를 통해 최종적으로 발생되는 폐기물 양을 줄이고 메탄 등의 바이오 가스를 얻어 이를 에너지로 얻기 위한 많은 공정들이 현장에 적용되고 있다. 하지만 혐기 소화 과정을 마친 후 유출되는 유출액은 고농도의 유기물질 및 암모니아성 질소, 인산염 등을 다량으로 함유하고 있어 적은 양이라도 하천이나 호수 등에 유입되면 수질 악화와 부영양화를 초래할 위험성이 크다. 이번 연구에서는 음식물류 폐기물로부터 바이오가스를 생산하기 위한 혐기소화 공정에서 발생하는 유출액의 방류수 수질기준 확보와 경제성을 만족시킬 수 있는 처리공정의 상용화 기술을 개발하기 위해 생물학적 처리， 물리 화학적 처리를 통합한 공정을 적용하였다. P건설사 혐기소화 유출액 pilot plant(1 ton/day) 운전 결과 50~70% 로 $NO_2$-N 이 약 1,000 mg/$\ell$정도로 축적되는 현상을 보였으며 상대적으로 $COD_{Cr}$의 농도는 400~600 mg/$\ell$로 C/N 비가 낮아 탈질이 어려울 것으로 판단하였다. 이에 실험실 규모에서의 실험을 진행하였다. $NO_2$-N와 $NO_3$-N을 기준으로 McCarty 양론비 기준 80% 에서 300%까지 메탄올을 주입해 제조 폐수와 실제폐수로 실험을 진행하였고 제조폐수로 실행된 실험에서 아질산 탈질의 효율을 확인하였다. 미생물이 메탄올에 순응 후 완전 탈질에 걸리는 시간은 약 2.5 일로 확인 되었으며 메탄올이 추가로 주입되지 않은 반응조의 $NO_2$-N의 탈질량은 메탄올이 이론값 100% 주입 된 반응조에 비해 30% 이하의 처리 효율을 나타냈다. 이론값을 기준으로 메탄올이 100% 주입된 반응조는 약 96.1%의 탈질 효율을 보였으며 메탄올 순응 후에 약 1.5 일의 HRT가 단축되었기 때문에 메탄올에 장시간 순응 시 탈질 효율이 더 좋아질 것으로 보인다. 아질산탈질에 대한 실험실 규모 연구결과를 토대로 pilot plant에서 재현성 검토를 목적으로 운전을 수행하였다. 무산소조의 HRT는 2.7 일 이었으며 호기조의 HRT는 4.1 일 이었다. 유입수의 평균 $COD_{Cr}$ 농도는 2,878 mg/L, T - N 농도는 2,723 mg/L로 나타났으며 $NO_2$-N 기준 C/N비 1.2-1.8의 메탄올을 주입하였을 때 96% 이상의 탈질율을 보였다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.491-498
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• 2005

J sewage treatment plant (WWTP) in Busan has used methanol as an external carbon source for the biological denitrification process. Methanol is widely used. but rather expensive and very dangerous in handling. Therefore, it has been required that the economic alternative carbon source must be developed. By-product from a fine chemical industry can be Purified by removing high molecular weight substances using the ultrafilter membrane separation process and RBDCOD fraction becomes $98{\sim}99%$ of COD substances in the purified by-product. The purified by-product containing three types of alcohols, methanol, prophylenglycol and methoxypropanol; showed similar chemical characteristics to the methanol, a main external carbon source, in biodegradation pathway. Shown above, the compatibility between main and alternative carbon sources has been achieved. Also very short or no adaptation period is necessary in the case of exchanging these carbon sources. The compatibility between external carbon sources is an essential element for stabilizing WWTP operations. During the full-scale application test of the by-product, the alternative carbon source line got on par with the treatment efficiency of the methanol line. With the test result, J-WWTP changed methanol to a fine chemical by-product, in two out of three J-WWTP lines. Moreover, it is expected that 55.4% of the external carbon source cost reduction can be achieved in the alternative carbon source applied lines.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.224-239
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• 2023

C-ITS (Cooperative-Intelligent Transportation System) refers to user safety-oriented technology and systems that provide forward traffic situation information based on a two-way wireless communication technology between vehicles or between vehicles and infrastructure. Since the Daejeon-Sejong pilot project in 2016, the C-ITS infrastructure has been installed at various locations to provide C-ITS safety services through highway and local government demonstration projects. In this study, a methodology was developed to verify the effectiveness of the warning information using individual vehicle data collected through the Gwangju Metropolitan City C-ITS demonstration project. The analysis of the effectiveness was largely divided into driving behavior impact analysis and environmental analysis. Compliance analysis and driving safety evaluation were performed for the driving impact analysis. In addition, to supplement the inadequate collection of Probe Vehicle Data (PVD) collected during the C-ITS demonstration project, Digital Tacho Graph ( DTG ) data was additionally collected and used for effect analysis. The results of the compliance analysis showed that drivers displayed reduced driving behavior in response to warning information based on a sufficient number of valid samples. Also, the results of calculating and analyzing driving safety indicators, such as jerk and acceleration noise, revealed that driving safety was improved due to the provision of warning information.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.2
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• pp.93-103
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• 1997

This study presents a way of improving the stability of fixed scroll in scroll compressors. For the scroll compressor whose fixed scroll is designed to move in the axial direction for the axial compliance, the fixed scroll is under the influence of the overturning moment produced by internal gas forces. Unless the overturning moment is properly compensated by the moments of reaction forces at the suspension of the fixed scroll to the compressor frame, the fixed scroll would exhibit wobbling motion, increasing gas leakage through the gap induced by the wobbling of the fixed scroll between the two scroll members. The conditions on which the wobbling motion can be suppressed have been found analytically; The axial position of the fixed scroll suspension should be made within a certain range. The upper limit of this range is the axial location for the o-rings which are inserted between the fixed scroll and the back pressure chamber to promote sealing for the gas in the back pressure chamber. And the lower limit is mainly determined by the magnitude of the axial sealing force. As long as the axial sealing force is not negative over all crank angles, the lower limit is not above the mid-height of the scroll wrap. Larger axial sealing force lower the lower limit.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.79-88
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• 2009

This paper presents the analytical stiffness analysis method for a low-DOF planar parallel manipulator. An n-DOF (n<3) planar parallel manipulator to which 1- or 2-DOF serial mechanism is connected in series may be used as a positioning device in planar tasks requring high payload and high speed. Differently from a 3-DOF planar parallel manipulator, an n-DOF planar parallel counterpart may be subject to constraint forces as well as actuation forces. Using the theory of reciprocal screws, the planar stiffness is modeled such that the moving platform is supported by three springs related to the reciprocal screws of actuations (n) and constraints (3-n). Then, the spring constants can be precisely determined by modeling the compliances of joints and links in serial chains. Finally, the stiffness of two kinds of 2-DOF planar parallel manipulators with simple and complex springs is analyzed. In order to show the effectiveness of the suggested method, the results of analytical stiffness analysis are compared to those of numerical stiffness analysis by using ADAMS.

• KDI Journal of Economic Policy
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• v.28 no.2
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• pp.97-129
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• 2006

This study investigates whether dynamic loan loss provisioning is necessary in Korean banking environments. Under the dynamic provisioning rule banks are required to accumulate additional reserves to general and specific provisionings in preparation for expected loan losses until maturity. This provisioning is most effective in the case that banks tend to recognize less loan losses in the business upturns and/or in the periods of increasing profits. The empirical study, however, shows that banks support procyclicality of loan loss privisioning and earning smoothing behavior over profit fluctuations. These findings suggest that Korea would not seriously need the introduction of dynamic loan loss provisioning. But this policy implication does not seem robust in view that the recent experience shows the countercyclicality of loan loss provisioning practices and negative correlation between earnings and provisioning after financial restructuring was completed. This result is partly attributable to vigorous shareholder activism because of high foreign ownership of most commercial banks. Once it is true that bank management is more interested in short-term performances, current loan loss provisioning would have attributes of impairing capital adequacy, hence strengthening loan loss provisiong requirements.

• Journal of agricultural medicine and community health
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• v.24 no.1
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• pp.35-47
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• 1999

Medication non-compliance among the elderly results in medical problems and substantial cost to the health care system. This study investigate predicted variable related to the medication task ability among elderly. This study was done in the selected 4 villages in Kimchun County of Kyungbuk Province from July to August, 1996. The subject was the resident that 202 adults above 60 years of age. The questionnaire of interview included medication task ability, socio-demographic data, COOP/WONCA chart, family ABGAR score. BDI(Beck depression inventory), ADL(activities of daily living), IADL(instrumental activities of daily living), and MMSE-K(minimental state examination-Korean version). The results were as followed : 1. Approximately 49% of study population was taking drug medication currently. We found that 93% of study population was successful at the medication task all alone, 6% was failure at the medication task all alone, so need help partly or completely. 2. Significant variables between group of medication task ability were age, educational attainment, IADL, and MMSE-K in univariate analysis. And significant correlated variables with medication task ability were ADL, IADL, MMSE-K, and BDI in correlation analysis. 3. Major predictors to medication task ability on multiple logistic regression were IADL and sex finally. Findings suggest that IADL is related to medication task ability than other test battery of health status, so IADL could be used to necessary for medication management and add information to conventional methods of assessing mental status.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.532-536
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• 2016

In this study, single-stage continuous anaerobic reactors to treat sewage sludge were operated under different temperature (55 and $35^{\circ}C$; $R_{TAD}$ and $R_{MAD}$) to evaluate the reactor stability and performance of the thermophilic and mesophilic anaerobic digestion. During the overall digestion, both anaerobic reactors maintained quite stable and constant pH and total alkalinity (TA) values in the range of 6.5-8.0 and 3-4 g $CaCO_3/L$, respectively. After the start-up period, $R_{TAD}$ showed 10% higher VS removal efficiency than that of $R_{MAD}$ ($R_{TAD}$; 43.3%; $R_{MAD}$ : 33.6%). Although organic acids such as acetic and propionic acid were detected in both anaerobic reactors at the start-up period, all organic acids in $R_{TAD}$ and $R_{MAD}$ were consumed at the steady state condition. Also $R_{TAD}$ showed 31.4 % higher methane production rate (MPR) than that of $R_{MAD}$ at the steady state condition ($R_{TAD}$; 243 mL $CH_4/L/d$; $R_{MAD}$ : 185 mL $CH_4/L/d$). Meanwhile, the experimental results indicated similar methane yield between $R_{TAD}$ and $R_{MAD}$.

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.775-812
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• 2008

This paper provides a theoretical approach to the New Zealand's Catch-Balancing Regime (CBR) with a reporting requirement under the Individual Transferable Quota (ITQ) system. The enforcement strategy depicted draws on recent literature regarding practical applications of the Revelation Principle. New Zealand's use of CBR-specific instruments such as deemed values, remains to be improved. However, some of its features can constitute a valuable example for regulators seeking to improve their methods of dealing with issues as bycatch or overfishing in order to maintain Total Allowable Catch (TAC) levels under emerging ITQ systems. The enforcement strategy analyzed has the potential to provide a more sustainable and efficient management of the fish stock, reduce discarding and stabilize monitoring costs, while improving the level of reporting compliance.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.335-342
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• 2003

In order to analyze the deformational behavior accurately, the in-situ testing technique which provides the reliable deformational characteristics at whole strain ranges, needs to be developed. The pressuremeter is a unique method for assessing directly the in-situ shear modulus of soils with strain amplitude. This paper introduces a new alternative, the cavity strain measuring system in pressuremeter designed for whole strain ranges of $10^{-5}$%∼20%. Not only in the synthetic calibration chamber but also in the field, the pressuremeter tests were performed to determine the compliance of the new developed pressuremeter system. The variation in shear modulus with strain amplitude above $5\times 10^{-2}$% was reliably determined by the developed pressuremeter. It is concluded that the major cause of error in small cavity strain measuring is not from the cavity strain measuring system but from the friction between measuring arm and membrane during unloading-reloading loops.