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        검색결과 529

        201.
        2017.04 구독 인증기관·개인회원 무료
        본 연구에서는 연륙연도 사업에 대응하는 경제성 및 안정성을 갖춘 쌍동선형 차도선의 개발을 위해 U형과 V형의 서로 다른 쌍 동선형을 CFD 해석을 수행하여 저항성능을 비교하였다. CFD 해석 결과 U형 쌍동선형의 경우 14kts 이상의 고속에서 선수부 파형에 이상 이 발생하여 정상적인 운행이 불가능하다 판단되었으며, 이에 비해 V형은 동일한 속도에서도 이상이 발생하지 않았으며, 또한 U형 쌍동선 형 대비 V형 쌍동선형의 경우, 저속에서는 U형 대비 높은 침수표면적에도 불구하고 거의 같은 RTS값을 보이지만, 고속으로 넘어가면 U형 에 비해 확연히 낮은 RTS값을 보임을 확인, V형의 쌍동선형이 U형에 비해 저항성능이 개선됨을 확인하였다.
        202.
        2017.04 구독 인증기관 무료, 개인회원 유료
        This paper aims to reveal the effects of the K-ε turbulence model on the performance analysis of battery cooling system for electric vehicle. The maximum temperature, the difference of temperature, and temperature distributions on the battery module were compared with and without K- ε turbulence model under the different flow rate. It was found that there was no need to apply K-ε turbulence model when the flow rate is over 500m3/h because the difference of maximum temperature is under the 6℃.
        3,000원
        203.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to analyze the performance of the beneficiaries of the SMEs(Small and Medium Enterprises) support project that has been handled online on the 'BizOK System', which is the integrated support system for SMEs in Incheon, by comparing before and after receiving support. Various performance indicators can be used, but this study used the rate of increase in sales, exports and employed manpower collected by the 'BizOK System'. Moreover, to analyze the trend of business performance by corporate feature, this study grouped the businesses into 7 categories including sales, business history, number of employees and capital. The results of this study are expected to be used in drawing implications for business support policies by utilizing them as basic data for enhancing efficiency of the support project and establishing corporate policies.
        4,000원
        204.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With increasing number construction of high-rise building which has about 40 to 60 floors there have been many kinds of problem which related with usage from vibration. To predict response acceleration, it is important to assess correct natural frequency. However, due to the noise of MEMS sensor, it is difficult to measure dynamic characteristic such as natural frequency when measuring ambient vibration using MEMS sensor within cell phone. Therefore, a comparative analysis on vibration measuring applications was performed after measuring ambient vibration of 2 skyscrappers which have height between 133.5~244.3m that are located in Seoul and Observation tower using I-jishin APP with noise reduction function of MEMS sensor in order to verify the effectiveness of low noise type vibration measurement APP.
        4,000원
        205.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The result of the previous work leads to the idea that the inner area of the hyperbolic shell generator should be minimized for the cooling tower with higher first natural frequency. In this study the inner area of the hyperbolic shell generator was graphically established under varying height of the throat and angle of the base lintel. From the graph, several shell geometries were selected and analysed in the aspect of the natural frequency. Three representative towers reinforced differently due to different first natural frequencies were analysed non-linearly and evaluated using a damage indicator based on the change of natural frequencies. The results demonstrated that the damage behaviour of the tower reinforced higher due to a lower first natural frequency was not necessarily advantageous than the others
        4,000원
        206.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 로봇을 이용한 과제 기반의 로봇 상지재활 치료가 뇌졸중 환자의 상지 운동기능과 일상생활수행 (Activities of Daily Living; ADL)능력에 어떤 효과가 있는지 체계적 고찰과 메타분석을 실시하여 검 증하고자 하였다. 연구방법 : 1980년부터 2015년 12월까지 발표된 국외 무작위 대조군 실험(Randomized Controlled Trial; RCT)연 구들 중에서 과제와 함께 이루어지는 상지 로봇 재활치료를 대상으로 분석을 실시했다. EMBASE, Ovid-Medline, PubMed, CINAHL, Cochran CENTRAL을 통해 문헌검색과 선별을 실시했고, Scottish Intercollegiate Guidelines Network (SIGN)으로 문헌의 질평가를 The Grading of Recommendations, Assessment, Development and Evaluation (GRADE)로 근거의 수준을 마련했다. Cochrane collaboration’s tool for assessing risk of bias로 편향을 측정하고 RevMan 5.3 소프트웨어로 메타분석을 실시했다. 개별 연구들의 대상자 수, 중재 전-후 평균값, 표준편차 등을 자료합성에 사용하였다. 결과 : 12편의 연구가 최종 선정되었고 실험군의 대상자수는 총 341명(남성 235명, 여성 106명), 연령은 60.50 ± 5.51세의 분포를 보였다. 대조군의 경우 대상자수가 모두 301명(남성 207명, 여성 94명)이었고 58.55 ± 17.1세의 연령대를 보였다. 운동기능 전체의 효과크기는 2.63, Fugl-Meyer Motor Assessment (FMA)가 2.98, Box and Block Test가 2.25로 기능증진에 효과가 있었고, ADL 수행능력에서는 기능적 독립성 측정 (Functional Independence Measure; FIM)의 3.04을 제외하고 효과가 없었다. 결론 : 과제기반의 로봇상지재활치료는 뇌졸중 환자의 상지 운동기능과 ADL 수행능력에 전반적인 효과를 줄 수 있다. 장기적인 관점에서 로봇을 이용한 상지재활치료의 효과여부의 확인을 위해 임상 평가의 점 수나 등급으로 산출되는 결과변수에 대한 세밀한 추가 연구가 필요하다.
        5,200원
        207.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The fisheries industry has led the Korean economy, and has been achieving high-level position in the world. However, this industry meets aging, low growth and profit. In order to overcome this critical situation, it is needed to understand the overall status of industry. In industry level, most of previous researches focused on ocean industry rather than fisheries. In addition, scholars have been getting a lot of attention about fisheries cooperatives, fishing-ports, methods of fishery, and manufacturing process in fisheries sector. The aim of this research is analysis of domestic fisheries industry’s managerial performance using data envelopment analysis(DEA) considering operating and scale view. Furthermore, the comparative analysis is performed by firm size, and industry type. In results, fisheries industry’s managerial performance is not high, overall. In more detail, most of big size firms are under decreasing returns to scale(DRS) status. Fishery processing industry’s performance is low, and fishery distribution industry has the best performance. This paper suggests that transferring operating capability from big firms to small firms, and policy supports and firm’s activities should be accompanied for high-value added in fisher, and fishery processing industries.
        4,900원
        208.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical models of composite floor systems with various thickness of phase change material and sizes of circular spacers were developed based on finite element analysis. In order to perform a heat transfer analysis, thermal properties of steels were determined and those of phase change material were estimated from experiment results. In addition, the thermal insulation performance of composite floor systems with respect to different thickness of phase change material and sizes of circular spacers was predicted. To verify the validity of analysis, analysis results were compared with vertical furnace fire test results of equivalent conditions. As a result, available thicknesses of phase change material and sizes of circular spacers were proposed to satisfy the thermal insulation criteria of Korean Standards.
        4,000원
        209.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For economic evaluation of integrated operation to sewage facilities, benefit-cost analysis was performed to watershed sewage works project in 7 watershed areas, 156 facilities. In this study, the cost before and after integrated operation was compared and benefits are calculated from the reduction of operators, increasement treated pollution loads, reduction cost through operation convenience, reduction water consumption through effluent reuse, and improvement of life benefit. The result showed that cost was 8,500million won and benefit was 16,747million won, so benefit was 49% higher than cost. B/C analysis result showed that B/C ratio was 1.97 and it is similar to other researches. The benefits of integrated operation included convenience of data management, increase of emergency response, decrease of complains with sewage which was not reflected numerically, so the benefits of integrated operation were expected much greater than this result.
        4,000원
        210.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of 27.12 MHz radio frequency (RF) heating on heat transfer phenomena during the thawing process of frozen food. To determine the velocity of the RF thawing machine, samples were frozen at -80oC and subjected to different power treatments. The phase change times (-5 to 0oC) of frozen radish were 30, 26, 13, and 8 min; those of pork sirloin were 38, 25, 11, and 5 min; those of rump were 23, 17, 11, and 6 min; those of chicken breast were 42, 29, 13, and 9 min; and those of tuna were 25, 23, 10, and 5 min at 50, 100, 200, and 400 W, respectively. The heating limit temperatures of the radish, pork sirloin, rump, chicken breast, and tuna samples were 19.5, 9.2, 21.8, 8.8, and 16.8oC at 50 W; 23.5, 15.5, 27.3, 12.3, and 19oC at 100 W; 42, 26.9, 45.7, 22.1, and 39.4oC at 200 W; and 48.5, 54.7, 63.6, 57.3, and 44.9oC at 400 W. These results suggest that high-power RF improves thawing velocity and heating limit temperatures, and that an improvement on the operation of the RF thawing machine, according to food temperatures, is needed.
        4,000원
        211.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study mechanically analyzed the performance of road substructures with focus on infiltration trenches of pavement substructures. METHODS: Water contents and response times for precipitation of pavement substructures were investigated via sensors buried near the infiltration trench to measure water contents. RESULTS : The results of the water contents of pavement systems constructed with an infiltration trench yield levels that were slightly increased by approximately 2% compared to those measured from general pavement systems. This water content difference of 2% resulted in a decrease in service life of less than two years. CONCLUSIONS: Service life reduction due to an infiltration trench is minimal, particularly when the trench is installed with proper caution.
        4,000원
        212.
        2017.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the seismic performance of solid reinforced concrete columns with triangular reinforcement details using nonlinear seismic analysis. The developed reinforcement details are economically feasible and rational, and facilitate shorter construction periods. By using a sophisticated nonlinear finite element analysis program, the accuracy and objectivity of the assessment process can be enhanced. Solution of the equations of motion is obtained by numerical integration using Hilber-Hughes-Taylor (HHT) algorithm. The proposed numerical method gives a realistic prediction of seismic performance throughout the input ground motions for several column specimens. As a result, developed triangular reinforcement details were designed to be superior to the existing reinforcement details in terms of required performance.
        4,000원
        213.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Distributed genetic algorithm (DGA), also known as island model or coarse-grained model, is a kind of parallel genetic algorithm, in which a population is partitioned into several sub-populations and each of them evolves with its own genetic operators to maintain diversity of individuals. It is known that DGA is superior to conventional genetic algorithm with a single population in terms of solution quality and computation time. Several researches have been conducted to evaluate effects of parameters on GAs, but there is no research work yet that deals with structure of DGA. In this study, we tried to evaluate performance of various genetic algorithms (GAs) for the famous symmetric traveling salesman problems. The considered GAs include a conventional serial GA (SGA) with IGX (Improved Greedy Crossover) and several DGAs with various combinations of crossover operators such as OX (Order Crossover), DPX (Distance Preserving Crossover), GX (Greedy Crossover), and IGX. Two distinct immigration policies, conventional noncompetitive policy and newly proposed competitive policy are also considered. To compare performance of GAs clearly, a series of analysis of variance (ANOVA) is conducted for several scenarios. The experimental results and ANOVAs show that DGAs outperform SGA in terms of computation time, while the solution quality is statistically the same. The most effective crossover operators are revealed as IGX and DPX, especially IGX is outstanding to improve solution quality regardless of type of GAs. In the perspective of immigration policy, the proposed competitive policy is slightly superior to the conventional policy when the problem size is large.
        4,000원
        214.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES : Visibility at night can be improved by using retroreflection for short distances and phosphorescent line markings for long distances. In this study, we analyzed the characteristics of the phosphorescent line marking through a laboratory luminance test. Field performance analysis was performed through tests conducted on the road. We also examined the luminance measurement methods using the digital image obtained during the phosphorescent visibility evaluation. METHODS : In this study, the laboratory luminance test of the phosphorescent line marking was conducted using seven specimens to characterize the luminance changes according to the type of the glass beads, the thickness of the phosphorescent line marking, and the brightness and irradiation time of the light source. Phosphorescent and general line markings were made at 150 m to investigate the field luminance performance. A preliminary review of the luminance measurement methods was made using a digital image from a digital singlelens reflex (DSLR) camera. The measured luminance ratio of the general and the phosphorescent line markings was compared with the calculated luminance ratio using luminance analysis. RESULTS: Through the laboratory luminance test, it was seen that the change in luminance, which corresponds to the brightness of the light source, appears large but the influence of the thickness and irradiation time is low. The field performance test of the phosphorescent line marking conducted on the road involved measuring the luminance on the day the marking was made and 7 days after the marking was made. The luminance was found to be 190 mcd/m2 at 30 min after sunset and approximately 10-12 mcd/m2 4h after sunset. The results of the luminance test were captured using a digital image for each time group. The luminance ratio of the phosphorescent line marking, when compared to that of the general line marking, showed a similar trend within a 13% maximum error. Additionally, when this luminance ratio is compared to the direct field measurement, it could be confirmed that the luminance ratio, as captured in the digital image, showed a similar tendency. CONCLUSIONS : 1) The change in luminance corresponding to the brightness of the light source is significant in comparison with that corresponding to the thickness and the irradiation time. In addition, the results of the field test for the phosphorescent line marking satisfied the phosphorescent fire protection standard. 2) We examined the validity of the luminance measurement method using a digital image and we concluded that the change in the luminance ratio shows a similar tendency in both the cases. The results can form the basis for luminance measurement methodology for the construction and maintenance of phosphorescent line markings.
        4,000원
        215.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        SLIM AU(A plus U-shaped) composite beam had been developed for not only reducing the story height in residential and commercial building, but also saving the cost of floor construction. The structural performance and economic feasibility was sufficiently approved by means of structural experiments and analytical studies. Even though fire resistance of the SLIM AU composite beam was evaluated throughout furnace fire test, the fire performance of the composite beam using finite element analysis is not analysed yet. Therefore the predictions of fire resistance simulations with loading as well as temperature distribution of the composite beam are summarized in this paper.
        4,000원
        216.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently damage of structures and loss of life by terrorism are internationally increasing. Among these terror that have a possibility to can happen in korea and that can caused lot of human life loss is the vehicle terror. To prevent the vehicle terror, the anti-ram barriers are needed. But domestic standard about anti-ram barriers are not clear. So, in this study, we will utilize and analyze the vehicle impact to evaluate the efficiency of the domestic bollard and suggest the installation standard of those. In Korea, granite, elastic, steel and stainless bollard are used. The performance of those bollard is not available. Elastic bollard couldn’t stop the vehicle, and the others just could stop the vehicle only at the speed under 10kph. Therefore, set the variable to reinforce, and evaluate the defence efficiency of bollard. As a result, granite and elastic bollard was not suitable for the anti-ram barriers. Performance of steel bollard increased as thickness grew. So steel bollard should must be thicker than 10T. And the concrete compressive strength effected insignificantly on the defence efficiency, so more than 24MPa compressive concrete be used. Performance of stainless bollard increased as thickness grew. So stainless bollard should must be thicker than 13T.
        4,000원