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        검색결과 162

        1.
        2021.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        KAERI has planned to carry out a series of dynamic tests using a shaking table and time-history analyses for a channel-type concrete shear wall to investigate its seismic performance because of the recently frequent occurrence of earthquakes in the south-eastern parts of Korea. The overall size of a test specimen is ×× 2500 mm×3500 mm×4500 mm, and it consists of three stories having slabs and walls with thicknesses of 140 mm and 150 mm, respectively. The system identification, FE model updating, and time-history analysis results for a test shear wall are presented herein. By applying the advanced system identification, so-called pLSCF, the improved modal parameters are extracted in the lower modes. Using three FE in-house packages, such as FEMtools, Ruaumoko, and VecTor4, the eigenanalyses are made for an initial FE model, resulting in consistency in eigenvalues. However, they exhibit relatively stiffer behavior, as much as 30 to 50% compared with those extracted from the test in the 1st and 2nd modes. The FE model updating is carried out to consider the 6-dofs spring stiffnesses at the wall base as major parameters by adopting a Bayesian type automatic updating algorithm to minimize the residuals in modal parameters. The updating results indicate that the highest sensitivity is apparent in the vertical translational springs at few locations ranging from 300 to 500% in variation. However, their changes seem to have no physical meaning because of the numerical values. Finally, using the updated FE model, the time-history responses are predicted by Ruaumoko at each floor where accelerometers are located. The accelerograms between test and analysis show an acceptable match in terms of maximum and minimum values. However, the magnitudes and patterns of floor response spectra seem somewhat different because of the slightly different input accelerograms and damping ratios involved.
        4,000원
        4.
        2017.10 구독 인증기관·개인회원 무료
        최근 건설재료의 자가치유 기술에 대한 많은 관심을 보이고 있으며, 유럽의 배수성 포장에 자가치유 아스팔트 포장 기술과 배수시설에 박테리아를 이용한 자가치유 콘크리트를 개발하고 있다. 본 연구에서는 유도가열 장치를 이용한 자가치유 아스팔트 포장의 자가치유 성능을 평가하고자 하였다. 스틸섬유를 아스팔트 포장에 혼입하여 아스팔트 포장을 만든 후 3점 피로균열 시험으로 균열을 유도하였다. 유도가열 장치를 이용하여 가열한 후 2-3시간의 휴지기간을 두어 3점 피로균열 시험을 다시 수행하여 자가치유 가능성을 평가하였다. 일반 골재뿐만 아니라 스틸글래그로 아스팔트 혼합물의 가열성능과 자가치유 성능도 평가하였다. 스필섬유의 분포상태를 분석하기 위하여 마이크로 CT-Scan장비를 이용하여 촬영하였다. 시험결과 스틸섬유를 이용하여 제작한 아스팔트 혼합물의 자가치유 가능성이 있었으며, 자가치유 성능정도를 분석하여 최적의 스틸섬유함량을 결정하였다. 다양한 조건에서 자가치유 성능을 평가하였으며, 매우 효과적인 것으로 나타났다
        5.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempted to establish the optimal conditions for storage of spring kimchi cabbage to stably control supply and demand. To this end, this study stored kimchi cabbages in various manners for different periods and compared the quality characteristics of kimchi using these cabbages. According to the results, pre-drying with photocatalytic and pre-cooling treatments showed average selectivity loss rates of 18.83 and 21.37%, respectively, which were lower than those of other treatments. Spring kimchi cabbages were stored for 15 weeks under various conditions, and the kimchi was stored for 4 weeks at 4°C. After ripening, each kimchi was analyzed for their soluble solid content, pH, acidity, and salinity. The average pH of kimchi was 4.60 and tended to rise, whereas average acidity was 0.38% and fell by 0.24 to 0.31% as the storage period was extended. Extension of the storage period caused decreases in soluble solid content and salinity, and the number of lactic acid bacteria decreased due to increased pH and reduced acidity (p<0.05). Sensory evaluation showed that all experts and non-professionals preferred kimchi treated by precooling compared to any other treatment.
        4,000원
        6.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To stabilize the supply of kimchi by extending the storage period of spring kimchi cabbage, this study manufactured kimchi from spring kimchi cabbage under varying storage conditions and periods, and analyzed their quality and sensory characteristics following the maturing period. Trimming loss was lowest in the group of plasma+reverse direction+predrying+ HDPE film processing. The salting yield of spring kimchi cabbage stored for 12 weeks was lower than that of spring kimchi cabbage stored for 6 weeks, and the kimchi yield was low in the pre-treatment group of spring kimchi cabbage stored for 12 weeks. The firmness was slightly different according to the storage period from one month of maturation. From the perspective of pH and acidity, the maturation in the reverse direction+pre-drying+HDPE film processing group was slower than that in the normal group (<0.05). In the sensory evaluation, the preference was increased in the low temperature storage processing group as the maturation period was increased (<0.05).
        4,000원
        7.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focuses on developing a theoretical framework for evaluating Operational Performance of the Marine Forest Creation project on a balanced and comprehensive perspective by using BSC, AHP, and IPA. Also, the purpose of this study is empirically to analyze operational performance of the project and to suggest the future improvement plan. For this purpose, We will first determine the critical success factors(CSF) and key performance indicators(KPI) required for evaluating the performance of the Marine Forest Creation project from the four perspectives of BSC. And, After determining the weight for each of CSF, KPI, and four perspectives of BSC by using AHP, we will measure the project performance. We will also conduct IPA analysis to propose the direction of improvement of the Marine Forest Creation project. The results of this study are as follows. First, this study has drawn 8 critical success factors and 16 key performance indicators for four BSC perspectives based on the theoretical considerations and expert interview survey. Second, as a result of deriving relative importance of BSC perspectives using AHP, customer perspective was the highest, followed by financial perspective, learning and growth perspective, and internal process perspective. Third, as the results of analyzing the importance and performance of BSC perspectives using IPA, customer perspective was the maintenance reinforcement category, financial perspective was the key improvement category, internal process perspective and learning and growth perspective were gradual improvement category. This study has a great academic significance in terms of BSC first tried to evaluate the performance of the Marine Forest Creation project. The results of this study are expected to lead to various discussions for a balanced and comprehensive verification of Marine Forest Creation project performance.
        5,400원
        8.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES :Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests.METHODS:This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672.RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete.CONCLUSIONS:This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.
        4,000원
        9.
        2016.06 구독 인증기관·개인회원 무료
        도로포장은 구조 및 재료 조건과 더불어 환경 및 교통하중 조건에 영향을 받아 러팅(Rutting), 피로균 열, 반사균열, 온도균열 등의 파손을 일으켜 설계수명에 도달하기 이전에 유지보수를 실시해야 하는 경우 가 자주 발생한다. 이러한 유지보수를 실시하는데 있어 기존의 파손된 도로 포장위에 아스팔트 덧씌우기 를 하는 방법이 있으며, 지난 2006년에는 탄소섬유와 유리섬유를 격자망으로 직조한 섬유보강재를 이용 한 아스팔트 덧씌우기 공법이 개발되어 2014년 기준 시공연장이 250km에 달한다. 최근 국・내외에서는 섬유보강재를 이용한 유지보수 방법의 효과를 확인하기 위한 연구가 활발히 진행되었다. 권세용 외(2005) 는 섬유보강 아스팔트 혼합물의 균열저항성 연구를 통해 덧씌우기 층의 층간 섬유 부착력은 아스팔트의 휨 강성 및 균열 저항성에 큰 영향을 끼친다는 연구결과를 보였다. 박상구 외(2010)는 이러한 섬유보강 아스팔트 포장의 부착 전단강도를 증가시키고 장기 공용성을 향상시키기 위해서는 시공시 표층 아스팔트 의 다짐 온도가 저하되지 않도록 노면절삭에서 표층 아스팔트 타설과 다짐까지의 작업을 연속적으로 수행 해야 한다는 연구결과를 보였다. 국내에서는 비교적 최근 섬유그리드 보강 아스팔트포장의 시공이 이루어졌기 때문에 초기의 거동 및 성능에 대한 검증은 이루어졌지만 일반 아스팔트포장의 거동 및 성능과의 장기적인 비교 분석이 아직까지 제대로 이루어지지 않은 실정이다. 본 연구의 목적은 장기공용성 조사를 위해 시공완료 후 5~8년이 경과된 구간의 아스팔트 덧씌우기 포장 의 거동과 공용성에 미치는 섬유그리드의 효과를 확인하는데 있다. 노후된 일반국도 아스팔트포장의 섬유그 리드 보강 아스팔트로 덧씌운 구간과 일반 아스팔트로 덧씌운 구간의 현황조사를 실시하였으며, 이들 구간 의 PMS자료와 노면촬영사진을 분석하여 파손현황을 비교하고, 현장에서 채취한 코어에 대해 실내실험을 실시하여 파괴에너지, 부착전단강도 등의 데이터를 획득하였다. 실험 분석 결과를 구조해석의 입력값으로 활용하여 섬유그리드 포장과 일반 아스팔트포장의 러팅, 피로균열 해석을 통해 거동을 비교하였다.
        10.
        2016.06 구독 인증기관·개인회원 무료
        아스팔트 덧씌우기는 어느 정도 파손이 진행된 아스팔트 포장이나 시멘트 콘크리트 포장 위에 아스팔 트 혼합물을 포설하는 포장 보수 공법으로 지난 2006년에는 탄소섬유와 유리섬유를 느슨한 격자막 형태 로 직조한 토목섬유 보강재를 노면에 부착하여 아스팔트 포장체의 균열저항성을 증진시킬 수 있는 섬유그 리드 보강 덧씌우기 공법이 개발되어 현재까지 136km의 달하는 구간에 시공되었다. 그에 따라 최근 국내 에서는 섬유그리드 보강 덧씌우기 포장의 효과를 확인하기 위한 연구가 활발히 진행되고 있다. 김광우 외 (1999)는 아스팔트 콘크리트 덧씌우기에서 야기되는 반사균열에 대한 저항성 향상을 위한 연구를 통해 유 리섬유 그리드로 보강된 아스팔트 혼합물이 반사균열 저지에 효과적이라는 연구결과를 보였다. 도영수 외 (2005)도 아스팔트 덧씌우기 포장에 나타나는 반사균열 제어를 목적으로 시멘트 콘크리트 포장과 아스팔 트 덧씌우기 포장 경계면에 보강재의 부착 방법을 달리하여 실내실험을 진행하였으며, 불포화 폴리에스터 수지 부착이 가장 효과인 것을 확인했다. 또한 박상구 외(2010)는 이러한 섬유보강 아스팔트 포장 부착의 전단강도를 개선하여 섬유보강 아스팔트 포장의 성능을 극대화하기 위한 연구를 진행하여 현장에서 지켜 야 할 만한 규정을 제안하였다. 국내에서의 섬유그리드 보강 덧씌우기 포장공법은 비교적 최신의 기술이기 때문에 일반 아스팔트 덧씌 우기 포장공법과의 장기적인 공용성 비교가 제대로 이루어지지 않은 실정이다. 따라서 본 연구에서는 섬 유그리드 보강 덧씌우기 포장 공법의 장기공용성 조사를 위해 재령 8년이 된 국내 고속도로 콘크리트 포 장의 PMS 데이터를 확보하여 추적조사와 구조해석을 실시하였다. 결과 분석을 통해 기존 콘크리트 포장을 섬유그리드로 보강하고 덧씌웠을 때가 그렇지 않은 경우보다 수명이 증진되는 것으로 나타났으며, 섬유그리드가 반사균열에 저항하는 것을 확인하였다.
        11.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 월동배추를 주로 이용하는 한국인의 전통적인 김장방법으로 인한 김장철 배추가격 급등락의 문제해결에 기 여하고자 상대적으로 사용도가 낮은 봄배추를 이용한 김치 의 저장기간 연장과 품질유지를 목적으로 수행되었다. 실험 결과, 경도는 수확시기가 가장 늦은 7월초 김치가 6월 중순 김치보다 유의적으로 높았으나(p<0.01) 숙성이 진행됨에 따 라 저장 8주차에는 수확시기에 따른 유의적인 차이를 보이 지 않았다. 김치 숙성과 상관성이 높은 pH와 산도 측정결과 전반적으로 저장 초기에 비해 pH는 감소하였고, 산도는 증 가하는 경향을 나타내었다. 관능평가 결과, 외관은 김치의 제 조시기와 숙성기를 종합하여 6월말 제조 김치의 외관이 가 장 우수하였고(p<0.05), 저장 4주차와 8주차에는 7월초 김치 가 가장 우수한 것으로 평가되었으나 유의적인 차이는 없었 다. 조직감 및 전반적인 기호도 항목에 있어서도 처리구별 유의적인 차이는 보이지 않았다. 따라서 수확시기에 차이를 둔 봄배추로 김치 제조 시 생배추 상태 또는 제조직후의 차이에 비해 절임과 숙성과정, 양념의 첨가 등을 통해 그 유의 적 차이가 감소됨에 따라 수확시기가 봄배추로 제조된 김치 품질에 미치는 영향은 크지 않음을 확인할 수 있었다. 다만, 수확시기가 가장 늦은 배추로 제조된 김치의 경우 생배추 상 태에서 경도가 유의적으로 높았으며 숙성기간 및 저장기간 이 연장되었으므로 이를 수확시기나 작황사정과 연결하여 차 후 심화된 연구가 필요할 것으로 사료된다.
        4,000원
        12.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: Reflection cracking has been one of the major causes of distress when asphalt pavement is laid on top of concrete pavement. This study evaluated the reflection cracking resistance of asphalt mixtures reinforced with asphalt embedded glass fiber and carbon fiber using a Texas Transportation Institute (TTI) overlay tester. METHODS : Different asphalt mixtures such as polymer-modified mastic asphalt (PSMA) and a dense graded asphalt mixture were reinforced with asphalt-embedded carbon fiber and glass fiber. For comparison purposes, two PSMA asphalt mixtures and one dense graded asphalt mixture were evaluated without fiber reinforcement. Two different overlay test modes, the repeated overlay test (R-OT) and monotonic overlay test (M-OT), were used to evaluate the reflection cracking resistance of asphalt mixtures at 0 ℃. In the R-OT test, the number of repeated load when the specimen failed was obtained. In the M-OT test, the tensile strength at the peak load and tensile strain were obtained. RESULTS : As expected, the fiber-reinforced asphalt mixture showed a higher reflection cracking resistance than the conventional nonreinforced asphalt mixtures based on the R-OT test and M-OT test. The dense graded asphalt mixture showed the least reflection cracking resistance and less resistance than the PSMA. CONCLUSIONS: The TTI overlay tester could be used to differentiate the reflection cracking resistance values of asphalt mixtures. Based on the R-OT and M-OT results, the carbon-fiber-reinforced asphalt mixture showed the highest reflection cracking resistance among the nonreinforced asphalt mixtures and glass-fiber-reinforced asphalt mixture.
        4,000원
        13.
        2016.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is important to select an accurate set of ground motions when conducting linear and nonlinear response history analyses of structures. This study proposes a method for selecting ground motions from a ground motion library with response spectra that match the target response spectrum mean, variance and correlation structures. This study also has addressed the determination of an appropriate value for the weight factor of a correlation structure. The proposed method is conceptually simple and straightforward, and does not involve a simulation algorithm. In this method, a desired number of ground motions are sequentially selected from first to last. The proposed method can be also used for selecting ground motions with response spectra that match the conditional spectrum. The accuracy and efficiency of the proposed procedure are verified with numerical examples.
        4,000원
        14.
        2015.10 구독 인증기관·개인회원 무료
        콘크리트 포장위에 아스팔트 포장 덧씌우기를 수행할 경우 반사균열이 만연하여 유지보수에 많은 예산 이 투입되고도 효과적인 유지보수 방법이 되지 못하여 많은 문제점으로 대두되고 있다. 본 연구에서는 반사균열을 모사할 수 있는 텍사스교통연구원의 덧씌우기 시험기(Texas Transportation Institute Overlay Tester: OT)를 이용하여 다양한 경우에 대하여 반사균열 저항성을 평가하였다. OT 시 험은 콘크리트 포장위의 아스팔트 덧씌우기 포장의 반사균열을 가장 잘 모사할 수 있는 기계로 알려져 있 다. 시험온도는 반사균열이 추운온도에서 섭시 0도로 하였으며, 수평으로 반복하중을 재하하였다. 시료는 PSMA, 밀입도, 그리드+PSMA, 그리드+밀입도 아스팔트 포장에 대하여 시험을 수행하였다. 시험결과 탄소섬유그리드+PSMA의 반사균열 저항성이 가장 컸으며, 밀입도의 반사균열 저항성이 가장 작았다. 시험결과를 이용하여 향후 콘크리트 포장위의 반사균열 저항성을 증진시키기 위한 시공법 개발의 기초자료로 사용할 수 있을 것이라 판단된다.
        15.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focuses on the case of FIRA(Korea Fisheries Resources Agency) and analysis the introduction effect of BSC(Balanced Score card) implementation. So it will set forth the improvement method and the implications for Quasi-governmental organizations which are trying to introduce or are operating the BSC system. This study suggests how to improve the problems of BSC as below : ① Building of reasonable and balanced evaluation index system ② Acquiring of comparability and equality through adjustments of group evaluated ③ Enhancing of competence and professionalism of evaluating group ④ Alleviating of difference gap of performance incentives and promoting of non-money incentives ⑤ Enhancing of positive acceptance and recognition for BSC.
        6,000원
        18.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: Surface treatment is a favorable method in the pavement preventive maintenance. This study (Part Ⅰ) aimed to develop the low viscosity filling material for waterproof characteristics and high penetrable and weather resistance, and a series of companion study (Part Ⅱ) presents the coating characteristics and performance analysis using field and lab tests. METHODS : Hydrophobic characteristics of the advanced surface treatment material are observed and measured the filling depth and the permeability for sand and asphalt pavement specimen using the water absorption test and permeability test, X-RAY CT test. Color difference for the weather resistance using ultraviolet ray accelerated weathering test is compared with asphalt pavement specimens. RESULTS : The developed material shows the decreased water absorption and increased impermeable effect because of the hydrophobic characteristics. It is found that the filling depth is about 6mm and weather resistance is better than asphalt pavement specimen. CONCLUSIONS: The advanced hydrophobic - low viscosity filling treatment material is developed in this study (Part Ⅰ) to improve the waterproof characteristics and high filling capacity and weather resistance for the pavement preventive maintenance.
        4,000원
        19.
        2013.12 구독 인증기관 무료, 개인회원 유료
        Korea' sport pedagogics has been developed mostly focusing on the area of physical education in schools. In the research area, the social capability education in the sport activity has been conceptualized as a educational term. The traditionally conceptualized affective domain education, the correct social attitude education and the recently appeared character education can be mentioned as examples. While such concepts, that are, the affective and social attitudes and character are effect to showing the direction of education in the ideology or goal level due to the inclusiveness of the concepts, the concepts are limited for securing the reality of education along with the content and the method of education. In other words, in the level of such concept, it is hard to define the reality of social capability education through the sports as required in our society. From such aspect, an alternative concept to guide to the reality of education is required in the sport pedagogics of Korea in the future. Therefore, in this study, the introspection is performed on what are the current meaning and limits following the trend of social capability education through sport activities of the sport pedagogics area in Korea while the future direction is suggested.
        4,300원
        20.
        2013.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is providing the educational plan for educational understanding and improvement to the students experienced and stopped elite sports until senior year of high school. For this purpose, the understanding of days of introductory courses and athletic experience, exercise in the circumstances to stop the process of setting up the course and after the break to hold on to experienced career barriers is needed. The purposeful sampling, one of the non-probability sampling of nomadic sampling method was performed to achieve the research purpose. The data were collected by way of in-depth interviews from two table tennis experienced student-athletes. Data analysis process to enhance the authenticity of the data from members of the review, expert consultation, the triangular method validation was performed. The first study, participants in two student-athletes were too early draft as athletes. Also, the selection process is the lack of systemicity and dosen’t consider personal speciality and aptitude of the students. Although there are difficulties in athletic life, the experience of accomplishment by win a prize during elementary school helps entrance into a middle school as a sports talent. Study participants were constantly perpetrated violence and hostel life because of the stigma caused by the interruption of the situation of potential movement was to continue his career. Process of social adaptation was categorized as confusion, goal setting, adaptive period and the embodiment process of established target. They feel confused by lack of information for entrance into a higher grade school. But they set a possible target and selected new course in the process of goal setting. Adaptaion process was classified as adaptation for learning, new interpersonal adaptation, and adaptation challenges for the unknown situation. The adaptation to school, there was a difficulty of continuing their studies basic academic skills are in short supply, but the effort went adaptation of schoolwork. There is no experience of student athletes, there is a positive effect, adaptation of new interpersonal relationships, helped in the formation of interpersonal relationships. Process of adaptation and challenge to the status of the unknown, but lack of experience, but it had a willingness to challenge you feel a lot of interest and curiosity to new experiences. Finally, at the stage of implementation of the targets set, attitude through the adaptation process to the society, and embodies the goal, and try to do the best with what we have seen. Third, were classified barriers difficulty of goal setting due to more absence factors of course barriers to movement stop student athletes recognized, wall of learning member, barriers experience the various components. This due to a shortage of information, did not experience most of the learning for the life of the movement part course search that takes into account the special ability or aptitude of the person has been impossible act difficult in the course of academic adaptation of exercise after discontinuation were. Can not be the general experience that not only learning experience, will require experience of school days, and had done gained a new experience to exercise after interruption. It presented a discussion for since the movement stop of study participants, the movement stops through the social adjustment process, to understand the course barriers to student players, it is a scheme seek understanding and education.
        6,600원
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