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        검색결과 193

        84.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As a result of an analysis of a damper system, a solution to a fire damper is developed using the continuity equation of damper control and orthogonal array. The fire damping device is made with a CAE software. Additionally, new H-120 grade fire damper is designed for the optimal offshore structure. This device will soon be tested on an actual offshore structure. An optimized fire temper is finally achieved using an orthogonal array. Using the result of present study will provide an environment friendly fire damper for offshore plants by choosing the optimum fire damper conditions
        4,000원
        85.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This research is to evaluate the mechanical performance of different types of Hot Mix Asphalt (HMA) pavement cells prepared for MN/Road field testing section through an extensive experimental analysis of air voids and simple statistical evaluation tools (i.e. hypothesis test). METHODS: An extensive experimental work was performed to measure air voids in 82 asphalt mixture cores (238 samples in total) obtained from nine different types of road cell located in MN/Road testing field. In order to numerically and quantitatively address the differences in air voids among the different test Cells built in MN/Road, a simple statistical test method (i.e. t-test) with 5% significance was used. RESULTS: Similar trends in air voids content were found among the mixtures including conventional HMA, Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) combined with taconite aggregate this provides support to the use of RAP and WMA technology in the constructions of asphalt pavement. However, in case of acid modified HMA mixtures, significant differences in air void content were observed between on the wheel path and between wheel path location, which implies negative performances in rutting and thermal cracking resistances. Conclusions : It can be concluded that use of RAP and WMA technology in the construction of conventional asphalt pavement and the use of PPA (Poly Phosphoric Acid) in combinations with SBS (Styrene Butadiene Styrene) in asphalt binder production provide satisfactory performance and, therefore, are highly recommended
        4,300원
        86.
        2014.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The present study aims to explore the factors affecting Korean EFL high school students’ choice of picture options with key expressions in a writing test prompt, as well as the effects of option position and contents on their performance. It further aims to examine whether these effects vary with English writing proficiency. The performance of lower- and higher-level students in two prompts was analyzed along with their reasons for their choices. The prompt had three picture options with two key expressions in each option; the students chose one picture option and wrote a 20-word message declining a request using a reason specified in the option. Significant effects were not found for position within the prompts, but for the content of the options. The participants tended to choose a certain picture option over others mainly because of topical knowledge, difficulty level, or picture preference. The findings suggest a significant effect of picture contents, which yields implications for designing prompts with picture options for score validity.
        6,400원
        87.
        2014.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate inter- and intra- rater reliability in an interview and a computerized oral test. It was also examined whether rater characteristics influenced on their reliability and biases, and finally the scores of both tests were compared with those of the Versant test using an automated computer rating system. For the study, the data from 21 Korean university students and 18 Korean or native speakers of English raters with various characteristics were collected. Some of the main findings from the study were as follows. First, rater severity was significantly different in each test, but each rater consistently graded on both tests suggesting lower inter-rater reliability and higher intra-rater reliability. Secondly, rater severity was impacted by the rater characteristics such as mother tongue, gender, age, and major. Lastly, there existed a positive correlation among the scores of the three tests, indicating that the scores of human beings and computers are strongly related.
        6,100원
        89.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine which spatiotemporal gait parameters obtained during hemiplegic walking could be a predictive factor for the Timed Up and Go test (TUG). Two hundreds nine subjects who had suffered a stroke were recruited for this study. They were participated in two assessments; the TUG test and gait analysis. The relationship between the TUG test and spatiotemporal parameters was analyzed using Pearson’s correlation coefficients. In addition, to predict the spatiotemporal gait parameters that correlated most with the TUG scores, we used multiple linear regression analyses (stepwise method). The results show that the normalized velocity was strongly correlated with the TUG performance (r=-.72, p<.001). Additionally, single support percentage (SSP), double support percentage (DSP), step time difference (STD), and step length difference (SLD) significantly were correlated with the TUG test. Normalized velocity, STD, DSP of affected side, and SSP of non-affected side explained 53%, 8%, 3%, 2%, of variance in the TUG test respectively. In conclusion, an increase in gait velocity and a decrease in STD would be effective indicators of improvement on the functional mobility in the stroke rehabilitation.
        4,000원
        91.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 2000~2010년까지 11년간 경남 소재 K 종돈장 Yorkshire 종빈돈 9,086두에 대한 자료를 근거로 하여 돼지의 주요 경제 형질인 등지방 두께, 등심단면적, 정육율, 일당증체량, 및 90 kg 도달일령에 영향을 미치는 환경효과를 추정하기 위하여 Harvey et al. (1979)의 최소제곱 평균법으로 SAS @9.2 Package/PC를 이용하여 분석하였으며(SAS Institute, 2006), 상이한 검정개시 체중과 검정 종료 체중을 보정하는 방법으로 검정종료 일령을 공변이로 포함하여 분석하였다. 본 연구의 결과를 요약하면 다음과 같다. 조사된 돼지의 주요 경제형질의 평균치와 표준 편차는 90kg 도달일령의 경우 147.537 ± 12.401 일, 일당증체량의 경우 614.614 ± 56.900 g, 보정 등지방 두께가 15.771 ± 3.071 mm, 등심단면적의 경우 28.644 ± 3.634 cm2, 정육율의 경우 55.363 ± 3.901%로 나타났다. 각 요인에 대한 유의성 검정 결과를 보면 조사된 모든 형질에 대해 출생 계절과 검정 계절의 효과에서 고도의 유의성(p<0.01)을 나타내었다. 표현형 상관에서 90 kg 도달일령과 일당증체량은 강한 부의 상관을 나타내었다. 90kg 도달일령과 등지방 두께는 정의 상관을, 일당증체량과 등지방 두께는 부의 상관을 나타내었다. 등지방두께와 등심단 면적은 -0.294의 부의 상관을 등지방두께와 정육율은 -0.723의 부의 상관을 나타내었다. 등심단면적과 정육율은 0.586의 정의 상관을 나타내었다. 본 연구에서 공변이 분석으로 포함한 종료체중의 효과에 대해 추정된 회귀계수는 검정종료일령에 대해 검정 종료 일령이 1일씩 증가함에 따라 등지방두께, 등심단면적, 정육율, 일당증체량, 90 kg 도달일령은 각각 -0.04 mm, -0.02 ㎠, 0.03%, -1.26 g, 0.61 일씩 변화하였으며, 특히 일당증체량과 90 kg 도달일령에 많은 영향을 미치는 것으로 사료된다. 이상의 연구결과를 통해 농장 검정돈의 표현형적 특성을 파악할 수 있었고, Yorkshire 종빈돈의 능력을 평가할 때 유전적 능력과 환경요인에 의한 부분을 고려하여야 할 것으로 사료된다. 또한 능력검정을 통한 우수한 종빈돈의 선발과 개량이 곧 현 국내의 축산업의 발전을 위한 노력의 기반이 될 것이다.
        4,000원
        92.
        2013.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        As indoor air cleaners have large sizes and high air flow rates, the test methods for particle cleaning capacity need to be reconsidered because the prescribed test chamber size becomes relatively smaller. In this study, air flow rate of air cleaners compared to test chamber size (Q/V) has been investigated by comparing the short-circuit factor which indicates the air mixed condition in the test chamber. The test method of Korea Air Cleaning Association (KACA) has been analysed and compared to that of Association of Home Appliance Manufacturers (AHAM) for clean air delivery rate (CADR) of two household air conditioners equipped with air cleaners having a maximum air flow rate of 15 m3/min in terms of initial particle concentrations, neutralized/non-charged particles, delay time before acquiring initial particle concentration, sampling positions. Constant short-circuit factor of about 0.9 was obtained in the range of Q/V less than 0.73 min-1. CADR based on KACA test method was somewhat dependent on initial particle concentrations, delay time before acquiring initial concentration, sampling positions. However, CADR based on AHAM test method was less dependent. Two or three minutes of delay time before acquiring initial concentration was necessary to reduce the variation of CADR according to initial particle concentration and sampling position.
        4,800원
        93.
        2012.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        According to a recent government study, development and distribution of functional building materials are increasing in Korea.
        In this study, we evaluated reduction performance of formaldehyde and toluene by sorptive building materials using small-scale chamber(20L) test method for 7 days.
        According to the results of this study, 18 building materials showed that the effects of formaldehyde reduction among the 23 building materials. And the number of the building materials with respect to its ability to reduce the concentration of toluene was relatively small.
        The mean sorption rate and total amount of sorption for formaldehyde were 36.8% and 1,525.4㎍/㎡, respectively. The sorption rate and total amount of sorption for formaldehyde were in the range 1.5∼78.4% and 87.5∼3,086.0㎍/㎡, respectively.
        And the mean sorption rate and total amount of sorption for toluene were 11.6% and 1,054.4㎍/㎡, respectively. The sorption rate and total amount of sorption of toluene were in the range 0.1∼62.4% and 29.6∼6,764.0㎍/㎡, respectively.
        In most cases, the performance of the building materials with respect to its ability to reduce the concentration of pollutants has steadily decreased within 7 days.
        4,200원
        96.
        2011.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study aims to provide preliminary review for standardization of methods for evaluating reduction performance of pollution-reducing building materials and to select commercially available pollution-reducing building materials for assessing their current status. The ISO 16000-23 and -24 standards were used as references for standardizing the test methods. The sub test categories—stability of the supply air concentration, type of the supply air, and supply air concentration—which were not included in the standards were selected and conducted for the purpose of this study. Five (5) wall materials and 2 ceiling materials were tested for formaldehyde reduction performance and 3 wall materials were tested for toluene reduction performance. The study included experimental review of the essential test criteria such as stability of the supply air, internal stability of the chamber, and recovery rate. The samples tested exhibited some reduction performance for formaldehyde but little reduction performance for toluene.
        4,300원
        97.
        2011.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This paper presented experimental results for circulation type UV-TiO2 photocatalytic oxidation process. We have developed UV-TiO2 photocatalytic oxidation process with activated carbon to control odor and VOCs in indoor and industrial applications. In this study, common indoor air pollutants, namely ammonia, formaldehyde, hydrogen disulfide, toluene were selected to investigate their efficiencies for UV-TiO2 photocatalytic oxidation. In high concentration test, the decomposition efficiency was high in order as ammonia, toluene, formaldehyde, hydrogen disulfide. Three type of individual processes are tested for ability to increase decomposition efficiency. UV-TiO2 photocatalytic oxidation combined process with activated carbon was excellent among the three type processes without reference to gas species. It was considered that this circulation type process will overcome short retention time for treatment for UV-TiO2 photocatalytic oxidation. It will promise that this circulation type UV-TiO2 photocatalytic oxidation combined process can apply indoor and industrial applications to remove odor and VOCs quickly.
        4,000원
        98.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 방제 작업을 하는데 있어서 과수농가 및 가로수의 병해충을 방제하기 위해 살포거리가 60m까지 살포할 수 있는 살포기를 개발하고 영상처리를 이용하여 성능실험 및 분석을 하는 것이다. 중소형 살포기의 성능을 알아보기 위해 살포기의 이동거리는 5m 간격으로 0~20m까지 5개의 실험구를 두었고 살포거리는 10~60m까지 6개의 실험구 총 30개의 실험구에 대한 영상 처리한 결과 다음과 같은 결과를 얻었다. 중소형 살포기가 이동하면서 흡수지에 살포한 데이터를 이치화 시킨 후 평균한 경우 전 구간에서 살포가 잘 된 것을 볼 수 있었고 살포기가 정지하면서 살포량이 낮게 나타났다. 중소형 살포기가 0.3m/s로 이동하면서 살포 한 경우 15m 이동한 경우 살포기에서 30m 떨어진 용지에 이치화 값이 121로 가장 살포가 높게 나타났다. 이동거리별 이치화 비율은 중소형 살포기가 출발하면서 살포한 경우가 살포율이 높게 나타났다. 이치화 결과에 의해 전구간에서 일정한 분포율을 나타냈다. 높게 나온 구간은 방제기가 출발한 점에서는 20m에서 50.23%, 방제기가 5m이동한 20m구간에서 50.21%, 10m 이동한 경우는 30m 구간에서 51.17, 15m 이동한 경우는 30m 구간에서 52.64%, 방제기가 정지하면서 살포한 경우는 20m의 구간에서 51.84%로 높게 나타났다. 이동거리별 검정색 비율은 방제기로부터 40m까지의 거리까지 살포가 원활하게 이루어지는 것으로 나타났다. 방제기가 15m 이동한 경우 60m의 구간에서 6.79%로 가장 낮게 나타났다.
        4,000원
        99.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Domestic SUV were evaluated for rating the ability of seat and head restraints to prevent neck injury in low speed rear-end crashes. The dynamic test criteria are divided into two groups-seat design parameters(Initial evaluation) and test dummy response parameters(Dynamic evaluation). Head restraint designs with initial geometric ratings of “acceptable" or “good" will be tested in a simulated 16 km/h rear impact to assess whether they provide effective dynamic support for the torso, neck and head. In the measurement and rating of static head restraint geometry, the initial static geometric rating of the domestic SUV cars were “good" except the A-car. In the final rating of the seat and head restraints, W-Car was “good", the other cars were “poor". The performance of dynamic test for the most part of the domestic SUV cars were “poor" and it is necessary to improve.
        4,000원
        100.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        컴퓨터와 비디오 게임은 현대 사회에서 주요한 놀이 문화 중에 하나이다. 이러한 놀이 문화의 특성을 가지고 있고 교육적인 내용을 포함한 기능성 게임은 향후 게임과 교육에서 핵심적인 역할을 해나갈 것이다. 본 연구에서는 기능성 게임을 사용하여 주관적인 관점이 기능성 게임의 수행에 어떤 영향을 주는지 알아보았다. 연구 결과, 기능성 게임을 게임이라고 여길 경우 높은 난이도의 과제 수행에서 검사라고 판단한 집단보다 낮은 오류율을 보였다. 이러한 결과는 주관적 관점이 과제 수행에서 보다 더 나은 수행을 야기하거나 과제 수행 전략의 변화를 가져온 결과로 인한 것이라 생각된다.
        4,000원
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