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        검색결과 432

        104.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper proposes damage indices efficient on evaluating the seismic safety of cable-stayed bridges, especially dual-plane, cable-stayed bridges with H-type pylons. The research assumes that the location of accelerometers is already defined as given in the 2017 Ministry of the Interior and Safety (MOIS) guideline. In other words, the paper does not attempt to suggest optimal sensor location for the seismic safety evaluation of cable-stayed bridges. The proposed damage indices are based on those for building structures widely applied in the field already. Those include changes in natural frequencies and changes in relative lateral displacements. In addition, the study proposes other efficient damage indices as the rotation changes at the top of pylons and in the midspan of the girder system. Sensitivity analysis for various damage indices is performed through dynamic analysis using selected earthquake ground motions. The paper compares the effectiveness of the damage indices.
        4,000원
        105.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        가상현실 기술이 발전하면서 다양한 영역에서 여러 목적으로 활용되고 있다. 하지만 사용자로부터 메스꺼움, 어지러 움 등과 같은 멀미 증상에 대한 부작용도 함께 보고되고 있다. 이런 멀미 증상을 사이버멀미라고 말하며, 사용자에게 불편을 야기시켜 불쾌감과 스트레스와 같은 부정적 영향을 줄 수 있으며, 현재 사이버멀미의 발생 원인과 해결책에 관한 공식적인 표준이 없다. 본 연구에서는 이런 한계점을 극복하기 위해 정량적, 객관적 사이버멀미 평가법을 제안하였다. 10명의 20대 남성 대상으로 이동과 회전을 하는 가상현실을 경험하게 하면서 128채널의 뇌파를 측정하였다. 11개 영역에서 Delta와 Alpha 상대 파워를 계산하고, ROC curve를 통해 area under the ROC curve (AUC)가 가장 높은 값을 가지는 다중회귀모형을 도출하였다. 이렇게 도출한 다중회귀모형은 11개의 설명변수로 피험자가 응답한 사이버멀 미의 정도와 비교하여 95.1 % (AUC = 0.951)의 정확성으로 사이버멀미를 구분하는 것이 가능함을 알 수 있었다. 이러한 결과를 정리하면 본 연구에서는 128 채널의 뇌파를 통해 멀미에 대한 객관적 반응을 확인하였으며, 뇌의 특정부 위에서 반응이 있는 것으로 나타났다. 본 연구 결과와 분석법을 활용하면 추후 사이버멀미 관련 연구에 도움이 될 수 있을 것으로 기대된다.
        5,200원
        109.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this paper is to develop an evaluation method for aged reclaimed asphalt pavements using RAP mortar specimen and FTIR method. METHODS: To evaluate the low-temperature behavior of aged reclaimed asphalt pavements, an indirect tensile strength test was adopted with an RAP mortar specimen. The RAP mortar specimen without a rejuvenator was fabricated with two fine aggregate types as a function of passing sieve sizes. The fabricated RAP mortar specimen was frozen for 24 h at -20℃. The indirect tensile strength was measured as a function of different absolute viscosities. The indirect tensile strength and displacement were varied as functions of the dosage of the rejuvenator. The spectroscopy analysis of four asphalt binders was performed under attenuated total reflection. The four asphalt binders comprised of a virgin binder, two extracted RAP binders, and a mixed virgin and extracted RAP binder. To evaluate the oxidation of the binder, the carbonyl index was calculated. RESULTS : The four extracted RAP binders were measured with an extremely wide range of absolute viscosity from 30,000 poise to 170,000 poise. The indirect tensile strength of the RAP mortar decreased as the absolute viscosity increased. This means that at lower temperatures, the indirect tensile strength can indicate the oxidation of RAP. Also, the indirect tensile strength and displacement changed sensitively as the dosage of the rejuvenator was changed. Based on the FTIR principle, a good relation was observed between the dosage of the rejuvenator and the FTIR absorbance peak. It can be used to estimate the dosage of the rejuvenator in hot reclaimed asphalt mixture. Also, the carbonyl index of the RAP binder was calculated to evaluate asphalt oxidation using the FTIR principle. CONCLUSIONS : There is a good relation between the indirect tensile strength of RAP mortar and its absolute viscosity. This indicates that RAP mortar can be used to estimate the properties of aged RAP. Also, the usage of rejuvenator can be evaluated with both the indirect tensile strength and FTIR absorbance peak. The carbonyl index can be used to predict asphalt oxidation.
        4,000원
        110.
        2019.04 구독 인증기관·개인회원 무료
        Grapholita molesta (Busck) is a major pest of stone fruits. Immature fruits of apricot and plum are well known food source during early summer for G. molesta, but those immature fruits have rarely been evaluated. Thus, we assessed biological and behavioral attributes of G. molesta when provided with immature fruits of apricot and plum in laboratory. The initial response rate (when larva reached to the center from release point in Y-tube olfactometer) of first instar was not different between apricot (70.0%) and plum (60.0%) of which sugar content was more on plum (5.92 brix in apricot and 7.30 brix in plum). However, pupal weight was less in apricot (7.5 mg) than in plum (11.4 mg), and this might be affected by difference in hardness of the fruits (17.2 N on apricot and 13.3 N on plum). The preoviposition period was also longer in apricot (6.3 d) than plum (3.6 d), and fecundity was lower on apricot (64.5) than on plum (135.0). Therefore immature plum fruit would be better food source for G. molesta than apricot during early summer.
        111.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농촌진흥청의 해외농업기술개발사업(Korea Programs on International Agriculture, KOPIA)의 성과를 분석하는데 목적이 있다. 이를 위해 2014년과 2015년에 종료된 태국, 볼리비아, 파라과이, 알제리, 에티오피아 KOPIA센터의 총 6개 사업을 대상으로 종료평가를 통해 사업성과를 분석하였다. 사업성과 평가를 위해 센터별 사업실적보고서 등에 대한 2차 자료 분석과 함께 센터별로 수원기관 직원, 농민 등 협력국 이해관계자들을 대상으로 구조화설문을 실시하였고, 현장방문을 통을 통해 성과를 종합적으로 분석하였다. 분석결과 농촌진흥청 KOPIA센터의 해외농업기술개발사업은 수원국 농업연구기관들과의 협력을 통한 과제 선정, 기술개발, 개발기술의 농가 지도·보급 등 공동수행으로 수원국의 정책목표에 부합하는 사업 선정부터 효율적인 사업운영이 이루어지는 것으로 평가되었다. 이를 통해 예산과 투입인력 대비 높은 수준의 사업효과를 달성하고 있으며, 수원국의 농가소득 증대 및 농촌개발 기반 마련 등의 성과를 달성하였다. 나아가 한국의 발전된 농업기술에 대한 신뢰도 제고는 물론 국내 농산업체의 해외진출에도 기여할 것으로 기대되고 있다. 다만 지속가능한 사업 추진을 위해 공동기술개발 외에 농업 생산성 향상을 위한 농자재 보급 등의 지원과 함께 지도·보급 활동을 통한 사후관리 강화가 요구된다.
        4,000원
        112.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Logistics companies are worrying about securing of differential competitiveness so as to be competitive companies in keen logistics market. The ground is how users are satisfied by sell-established service system to respond not only economic feasibility of logistics costs but also diversity and advancement of logistics needs. The competitiveness of logistics companies is also caused by customer satisfaction of service and only companies finding and satisfying customer needs continuously may be more competitive. For the competitiveness, it’s the most important to analyze demands of current and potential customers and their pursuing value properly. Therefore, this researcher grasped PSL for online logistics service users with 5-point Likert-scale and quality-level decision method that consider the weighted value based on Kano model, measured customer’s potential Demand for service through PCDI, and suggested methodology for deciding the priority of the improvement with loss function of Taguchi.
        4,000원
        113.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to develop and evaluate a nutrition education program that was designed to increase the knowledge, attitudes, and skills of Korean adults regarding nutrition labeling. The education program was 45 minutes of short-term training, which was conducted in the form of lectures and exercises. The contents of the program were as follows: in the introduction stage, talking about status and reasons for checking nutrition labels; in the development stage, explanation of nutrition labeling and their content, reading, and identifying sample nutrition labels, as well as comparing nutrition labels and selecting better foods; in the closing stage, summary of nutrition labeling and a pledge to check nutrition labels when purchasing processed food. A total of 53 adults (88.5% female) aged 30 years and over participated in this study. The nutrition labeling awareness of the subjects was increased significantly from 55.8 to 96.2% after the education. After the education, the correct recognition rate of a nutrition label was increased significantly from 26.9 to 78.8% for the amount of food, from 25.0 to 73.1% for the calorie content, from 36.5 to 69.2% for the nutrient contents, and from 30.8 to 82.7% for the percent daily value. The self-efficacy of checking nutrition labels was also increased significantly compared to that before the education. The overall satisfaction score of the nutrition education program was 4.2 out of 5. The outcome showed that the nutrition education program of nutrition labeling improved the participants’ awareness and self-efficacy towards checking nutrition labels.
        4,000원
        114.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Appropriate water level is the primary factor for the optimal yield of crop plants. The required water level varies according to the variety of the crops. In the present study, we investigated the optimum requirement of groundwater level(GWL) to grow sorghum and adzuki bean under paddy field soil. Here, we cultivated sorghum and adzuki bean using lysimeter filled with paddy soil under GWL 0 cm(NT) and GWL(20, 40 cm) where GWL 20 cm is maintained as a waterlogging condition. The plant growth promoting attributes were measured on the first day after treatment(0 DAT), 10 DAT and 20 DAT. The results showed that the growth parameter such as shoot length, leaf length, leaf width, and stem thickness of both sorghum and adzuki bean were constantly increased and were found higher at GWL 40 cm(except stem thickness and leaf width in sorghum at 20 DAT). The physiological parameters such as chlorophyll content and stomatal conductance were also found higher at GWL 40 cm in all DAT. In addition, the elements like P and K contents in adzuki bean, and Ca content in sorghum were constantly increased and was found higher in GWL 40 cm at all DAT. These results suggest that the GWL of 40 cm is appropriate for production of sorghum and adzuki bean especially in case of paddy soil.
        4,500원
        115.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study was conducted to develop a traffic accident prediction model using traffic accident data and management and service evaluation data on bus companies in Busan, and to determine the possibility of establishing customized traffic accident prevention measures for each company. METHODS: First, we collected basic data on the characteristics of urban bus traffic accidents and conducted basic statistical analysis. Then, we developed traffic accident prediction models using Poisson regression and negative binomial regression to examine the characteristics of major items of management and service evaluation affecting traffic accidents. RESULTS : The Poisson regression model showed overdispersion; hence, the negative binomial regression model was selected. The results of the traffic accident prediction model developed using negative binomial regression are acceptable at 95% confidence level (a = 0.05). CONCLUSIONS : The traffic accident prediction model indicates that the management of the traffic record system and internal and external management items in service evaluation have a significant effect on the reduction of traffic accidents. In particular, because human factors are the main cause of traffic accidents, bus traffic accidents are expected to greatly decrease if drivers' dangerous driving behaviors are effectively controlled by bus companies.
        4,000원
        118.
        2018.10 구독 인증기관·개인회원 무료
        The organism evaluation equipment (OEE) was developed to determine the insecticidal effect of atmospheric-pressure plasma jets (APPJ). The equipment consisted of a plasma-generating acrylic chamber (PGAC) equipped with a plasma generator, a plasma-maintaining acrylic chamber (PMAC), and plasma efficacy evaluation container (PEEC). The amount of reactive oxygen species (ROS) directly exposed to PEEC in the PMAC was measured using an ozone calculator. The ROS concentration in the PGAC and PEEC increased over time, and the optimum position for the PEEC was selected showing the lowest variance of ROS concentration. Based on the established equipment, five major insect pests (Aphis gossypii, Bemisia tabaci, Helicoverpa armigera, Tetranychus kanzawai, and Thrips palmi) were tested, and their knockdown time, recovery time, and median lethal time (LT50) were determined. As a result, B. tabaci showed the fastest knockdown in respond to the plasma, but the remaining insect pests were knock downed within 2-3 min. Recovery was the fastest in T. palmi and T. kanzawai and slowest in B. tabaci. The LT50 were determined as 13 and 16 min in B. tabaci and T. palmi, respectively. However, the LT50 of other insect pests showed over 21 min. In conclusion, the OEE system can be used to measure the optimum exposure time of plasma against various insect pests, and the plasma might be used as an alternative tools for pest control in the future.
        119.
        2018.10 구독 인증기관·개인회원 무료
        진딧물류의 기생성 천적인 쌍꼬리진디벌(Binozys communis)의 진딧물 밀도억제을 조사하기 위해 천적:진딧물을 1:15, 1:10, 1:5의 비율로 접종한 결과, 1:10으로 접종 시 5일차에 첫 머미가 발생하고, 진딧물의 총 개체수도 감소하기 시작하여 8일차부터 진딧물보다 머미의 수가 많아졌다. 쌍꼬리진디벌의 온도별 발육기간은 온도가 높아짐에 따라 알에서 머미까지의 발육기간은 짧아지며 20℃에서는 15.7, 25℃에서는 11.1일, 30℃에서는 10.0일이었고, 암컷 성충의 생육기간은 20℃에서는 3.1일, 25℃에서는 2.5일, 30℃에서는 1.5일이었다.
        120.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 한국어 쓰기 교육을 위한 교육용 게임으로서 text-to-scene 모델을 제안한다. 사용자 입력 문장에 대해 즉각적인 피드백을 제공하기 위해서, 제안하는 text-to-scene 모델은 사용자 입력 문장의 의미구조를 분석하여 장면을 자동으로 생성한다. 사용자가 문장을 교정하면서 자연스럽게 한국어 쓰기 능력이 향상될 수 있도록, 제안하는 text-to-scene 모델은 정답 장면과 사용자 입력 문장에 대한 장면을 함께 제공하므로, 사용자는 입력 문장의 어느 부분이 잘못되었는지 쉽게 파악하고 문장을 수정할 수 있다. 기존의 text-to-scene 연구에서 정교하게 장면을 생성하기 위해서는 필요한 자원 구축이 어렵고 처리 과정이 매우 복잡하다는 점을 고려하여, 제안하는 text-to-scene 모델은 외국인이 쉽게 이해할 수 있는 수준으로 장면을 단순하게 표현한다. 실험결과 격조사나 문장 요소 생략 등을 고려하여 15개의 단어를 임의로 조합하여 5개 어절 이내의 문장 1,048,576개 문장을 만들어 실험한 결과 제안하는 모델은 한 문장당 평균 14.94ms가 소요하면서 안정적으로 장면을 생성하였다. 외국인을 대상으로 한 작문 시험 결과, 종이를 이용한 작문 결과에서는 10개 문항 중 오답 문장이 평균 4.7개 나왔는데, 제안하는 text-to-scene 모델을 이용한 작문 결과에서는 한 문장 당 평균 1.56회의 미리보기를 하고 문장을 수정하여 0.87개가 나왔다.
        4,000원