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        검색결과 150

        101.
        2017.05 서비스 종료(열람 제한)
        화석연료의 고갈로 인한 고유가 상황과 온실가스에 의한 지구온난화가 가시화 되면서 재생 가능한 에너지개발과 자원의 효과적인 이용을 통한 자원순환사회 구축, 나아가 친환경적인 사회구현이라는 목표를 달성하기 위하여 선진국을 중심으로 환경과 에너지 문제를 해결하기 위한 연구가 진행되어 왔다. 이러한 전망을 토대로 국가적 부담을 최소화하고 실리를 추구할 수 있는 적극적이고 능동적인 대처방안을 강구할 필요성이 절실한 시점이다. 최근 신재생에너지의 확충과 기후변화 협약에 대한 적극적인 대응이 요구됨에 따라 단순 매립되던 폐기물을 에너지로 전환하여 처리하는 방식이 각광받으며 정부 계획 하에 적극적으로 추진되고 있다. 이러한 대응의 일환으로 1990년대 후반에는 유렵을 중심으로 연성에너지 체제에 부합하면서 지방자치단체 지역 공동체, 지역 주민들의 에너지 생산 활동 참여를 중시하는 지역에너지 체제가 대안으로 제시되었다. 에너지자립마을은 화석연료에 대한 의존도가 낮으며 지속가능한 마을과 유사한 것으로, 환경문제와 미래에너지 문제를 함께 고려한 개념으로 마을에서 발생되는 자원을 최대한 이용하고, 그 자원을 순환시키는 마을로 이해될 수 있다. 국내에서는 2009년부터 농림수산식품부, 환경부, 지식경제부 등 정부부처가 합동으로 각종 바이오매스를 이용하여 에너지 자립형 마을 시범사업을 추진하면서 축산 바이오매스를 이용하는 바이오가스화 기술은 농촌 지역에 도입할 수 있는 가장 실행 가능한 기술로 평가받고 있다. 본 연구에서는 농촌형 에너지자립마을에서 발생될 수 있는 다양한 유기성폐기물을 대상으로 혼합 원료의 특성과 병합 혐기성소화의 효율을 평가하기 위하여 biochemical methane potential test(BMP test)를 진행하였다. 또한, 본 연구를 바탕으로 혐기성소화와 C/N비의 관계를 알아보고자 하였다.
        102.
        2017.04 서비스 종료(열람 제한)
        In maintaining infra-structure, the conventional assessment and maintenance system has focused on safety. As the importance of performance-based assessment increases, considering the performance indices has became essential to assess in perspective of comprehensive evaluation of infrastructure. Therefore, in this study, the conventional evaluation system in Korea and suggested future direction of the maintenance system are analyzed.
        103.
        2017.04 서비스 종료(열람 제한)
        With the development of national industry, the number of social infrastructure facilities is gradually increasing. In addition, as time goes by, the aging of facilities is progressing gradually. For this reason, the importance of maintenance to ensure the safety of facilities is continuously increasing. However, there is still a lack of effective ways to invest the maintenance budget of facilities. For this reason, advanced foreign countries are actively studying facilities asset management techniques. In this study, construction cost and depreciation method of existing major facilities(1,2 class) were applied to examine the asset size of existing facilities according to changes in the service life of facilities.
        104.
        2017.04 서비스 종료(열람 제한)
        Domestic infrastructure facilities were built intensively in the 1970s and 1990s, and the resources required for maintenance and repair will increase sharply within the next 20 years. ‘A Comparative Study on the Classification and Financial Size of SOC(2012)’ showed that the size of the domestic infrastructure facility is shrinking. In this study, we investigated the case of asset management research and analyzed the trend of the aging of the domestic infrastructure. And then we present the direction of future research.
        105.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        In maintaining infra-structure, the conventional assessment and maintenance system has focused on safety. As the importance of performance-based assessment increases, considering the performance indices has became essential to assess in perspective of comprehensive evaluation of infrastructure. Therefore, in this study, the conventional evaluation system in Korea and suggested future direction of the maintenance system are analyzed.
        106.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        With the development of national industry, the number of social infrastructure facilities is gradually increasing. In addition, as time goes by, the aging of facilities is progressing gradually. For this reason, the importance of maintenance to ensure the safety of facilities is continuously increasing. However, there is still a lack of effective ways to invest the maintenance budget of facilities. For this reason, advanced foreign countries are actively studying facilities asset management techniques. In this study, construction cost and depreciation method of existing major facilities(1,2 class) were applied to examine the asset size of existing facilities according to changes in the service life of facilities.
        107.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        Domestic infrastructure facilities were built intensively in the 1970s and 1990s, and the resources required for maintenance and repair will increase sharply within the next 20 years. ‘A Comparative Study on the Classification and Financial Size of SOC(2012)’ showed that the size of the domestic infrastructure facility is shrinking. In this study, we investigated the case of asset management research and analyzed the trend of the aging of the domestic infrastructure. And then we present the direction of future research.
        108.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        A new prediction scheme has been proposed for the robust teleoperation in a non-visible environment. The positioning error caused by the time delay in the non-visible environment has been compensated for by the Smith predictor and the sensory data have been estimated by the Grey model. The Smith predictor is effective for the compensation of the positioning error caused by the time delay with a precise system model. Therefore the dynamic model of a mobile robot has been used in this research. To minimize the unstable and erroneous states caused by the time delay, the estimated sensor data have been sent to the operator. Through simulations, the possibility of compensating the errors caused by the time delay has been verified using the Smith predictor. Also the estimation reliability of the measurement data has been demonstrated. Robust teleoperations in a non-visible environment have been performed with a mobile robot to avoid the obstacles effective to go to the target position by the proposed prediction scheme which combines the Smith predictor and the Grey model. Even though the human operator is involved in the teleoperation loop, the compensation effects have been clearly demonstrated.
        109.
        2016.10 서비스 종료(열람 제한)
        Background : Constipation is can refer to bowel movements that are rare or hard for pass. Constipation is common symptom in current people and the treatment of constipation focused on the use of medicines or physical intervention. The aim of this study are investigates the effects of modified-extracts of Salicornia herbacea (S. herbacea) L. on constipation model. Methods and Results : To investigate the effect of these extracts on constipation model with Sprague-Dawley rats by loperamide administration, we orally administered various dosage of modified-extracts of S. herbacea. L. Then, we checked constipation-related parameters such as fecal number, colon weight, colonic transmit length, colon length as compared to the controls and ameliorated in a dose dependent manner. The results indicated that modified-extracts of S. herbacea. L. was ameliorated constipation in SD rat model. Conclusion : Based on the results, modified-extracts of S. herbacea L. and its many ingredients were considered to have effects on constipation.
        110.
        2016.10 서비스 종료(열람 제한)
        Maintenance of facilities is also growing in importance with the increased quantity. In developed countries, it is trying to introduce the asset management of the facility. In addition, the Korea Accounting guidelines presents a valuation method for the facility. In this study, we investigated the methods presented in infrastructure assets for accounting guidelines.
        111.
        2016.10 서비스 종료(열람 제한)
        By amending of the special law on the safety management of the facility, underground structure have been incorporated into kinds of facilities. In this paper, an inspection manual for the underground structure will be introduced.
        112.
        2016.09 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the characteristic and efficiency of anaerobic digestion (AD) of various organic wastes, and to find a way to enhance the efficiency of AD. Ten types of organic wastes including slaughterhouse waste (SHW), agricultural by-products (AB), animal manure (AM), sewage sludge, and food waste (FW) were selected. Elementary analysis was carried out to confirm the effect of C/N ratio on AD. Elementary analysis of the AB of maize showed the highest C/N ratio of 42.55. The lowest C/N ratio of 3.41 and 3.46, respectively, appeared from the SHW of the blood from cattle and swine. The cattle rumen content of SHW had a C/N ratio of 19.2, which was included at range of optimum C/N ratio, and AM showed a low C/N ratio because of the lack of a carbon source. The AB of beets had the highest biogas yield of 0.81 m3/kgVS, which was measured by the BMP test. Biodegradability was also calculated based on the BMP test result. FW was found to have the highest biodegradability of 92.14%. However, cattle rumen contents had low biodegradability (34.02%) because their substrate material consists of fibroid, while AM had the lowest biodegradability (15.34%) because of its low C/N ratio.
        113.
        2016.04 서비스 종료(열람 제한)
        In this study, we use the general national road's bridge format information to carry out the efficient maintenance services. Especially maintenance method of the operating new-type girder bridges is treated by collecting the information of them
        114.
        2016.04 서비스 종료(열람 제한)
        The results of considerations on the current state of PSC Box girder safety maintenance with external tendons, it appears the extra suggestion of safety maintenance and popularization of technique is needed.
        115.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        In this study the optimum conditions for recovery of valuable metal in Electric Arc Furnace Dusts were investigated. 2M of H2SO4, 1~5 of solid/liquid ratio, 0~180 min of leaching time has been established for leaching condition, and for electrowinning, each of Pt, C, Zn, Pb anode and Zn, Cu cathode was compared respectively at pH 2, 4 and 6. The result of elemental analysis of Zn crystal, a lagre quantity of Fe and H has been observed with Zn and other heavy metal, therefore, impurities removing process would be requir for enhancing purity of Zn. As the result, about 60% of Zn has been recovered under condition of 2 M of H2SO4, 1:2 of S/L ratio at 120 min, and Pt or Pb for anode, Zn for cathode has been shown the highest efficiency of electrowinning at pH 6.
        116.
        2015.10 서비스 종료(열람 제한)
        Recently, Korea Bridge Design Code(limit state design method) was introduced in 2012.However, Korea Infrastructure’s Safety Inspection Guideline are still following the bridge safety assessment. The assessment methods are classified according to material and bridge superstructure. Steel box girder bridge safety assessment was carried out by the A.S.D. In this study, introduce of steel box girder bridge safety assessment in accordance with the standards change.
        117.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        최근 국내외적으로 수중 유도무기체계 개발로 다양한 형태의 수중운동체 기술이 발전되고 있다. 특히 수중운동체 중 하나인 잠수함 은 한국의 특수한 상황에서 최적의 선형설계를 위한 신뢰도 높은 조종성 평가 기술이 요구되며, 이를 위한 정확한 동유체력 계수의 추정 또한 중요한 연구 분야라 할 수 있다. 따라서 본 논문에서는 잠수함 모형을 대상으로 구속모형시험인 VPMM (Vertical Planar Motion Mechanism) 시험을 실시하여 정밀도 높은 동유체력 계수를 추정하였다. 그리고 추정된 연직면 운동에 대한 선형 (Linear) 동유체력 계수 (Hydrodynamic derivatives)들을 이용하여 동안정성 (Dynamic Stability)을 판별하였다. 그 결과, 이론추정치와의 비교를 통해 동유체력 계수의 타당성이 검증 되었으며, 잠수함의 연직면 동안정성도 양호한 것으로 평가되었다. 즉, 무한수심으로 정의되는 심도 6.0의 깊은 수심으로 갈수록 주기에 따른 변화가 작아지며, 이론추정치에 근사함을 확인할 수 있었다. 한편 연직면 동안정성 판별에 있어서는, 0보다 큰 양(+)의 값을 가짐으로서 연직면 운동에 대한 동안정성을 만족하는 것으로 나타났다.
        118.
        2015.05 서비스 종료(열람 제한)
        본 연구에서는 바이오메탄을 생산하는 혐기성 소화에 대한 연구를 다루었다. 특히 여러 원료의 병합소화가 단일소화에 비해 높은 효율을 보였으며, 이를 기반으로 병합소화의 효율을 개선하기 위한 연구를 수행하였다. 병합소화의 원료로는 도축폐기물, 도축하수슬러지 및 탈수케이크, 가축분뇨, 그리고 농업 부산물을 사용하였으며, 각 원료의 기초성상분석과 성분분석을 통하여 최적의 혼합비율을 찾아내는 것이 목적이다. 혼합비율 최적화는 C/N비를 기반으로 하여 진행하였으며, 각 원료의 단일 혐기성소화 효율 및 혼합비율별 병합 혐기성소화 효율을 BMP test를 통하여 확인하였다. 질소의 함량이 높은 도축 및 분뇨 폐기물과 탄소원이 많은 농업 부산물의 병합 혐기성소화는 적절한 C/N비를 도출하는 데에 있어서 가장 적합하다고 판단되며, 이를 이용하여 다양한 유기성 폐기물의 혼합처리 기술의 개발이 가능할 것으로 예상된다.
        119.
        2015.04 서비스 종료(열람 제한)
        Recently, Korea Bridge Design Code(KBDC) adapts to the Limit State Design method(L.S.D) in 2012 according to the liberalization of construction market and the flow of international standardization of the design criteria. However, Korea Infrastructure’s Safety Inspection Guideline(KISIG) are still following the bridge safety evaluation applying the A.S.D and U.S.D methods. In this study, introduction of PSC bridge safety evaluation with L.S.D considered the traditional safety evaluation compared to the ASD and USD methods.
        120.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        본 논문은 혁신선호 경향이 강한(조기수용자) 학생들의 G러닝 활용 동기와 G러닝을 통한 학 습 효과성을 분석하였다. 이 분석을 통해 혁신선호 경향이 강한 학생들의 G러닝 활용 동기는 사회적 관계와 유행, 과시라는 것을 밝혔다. 또 이 학생들은 G러닝 학습 과정에서 높은 몰입도 와 흥미도를 나타내며, 결과적으로 학습성취도도 높다는 사실을 확인하였다.
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