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        검색결과 424

        22.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The initial smoothness of concrete pavement surfaces must be secured to ensure better driving performance and user comfort. The roughness was measured after hardening the concrete pavement in Korea. When the initial roughness is poor, relatively large-scale repair works, such as milling or reconstruction must be performed. Hence, a method to measure the roughness of the concrete pavements in realtime during construction and immediately correct the abnormal roughness was developed in this study. METHODS : The profile of a concrete pavement section was measured at a construction site using sensors that were attached to the tinning equipment of the paver. The measured data included outliers and noise caused by the sensor and vibration of the paving equipment, respectively, which were further calibrated. Consequently, the calibrated data were input into the ProVAL program to calculate the roughness based on the international roughness index (IRI). Additionally, the profile of the section was re-measured using another method to verify the reliability of the calculated IRI. RESULTS : The profile data measured at the concrete pavement construction site were calibrated using methods, such as overlapped boxplot outlier removal and low-pass filtering. The outlier data from the global positioning system (GPS), which was installed to identify the construction distance, was also calibrated. The IRI was calculated using the ProVAL program by matching the measured profile and GPS data, and applying the moving average method. The calculated IRI was compared to that measured using another method, and the difference was within the tolerance. CONCLUSIONS : A method to measure the roughness of the concrete pavements in real time during construction was developed in this study. Hence, the performance of concrete pavements can be improved by enhancing the roughness of the pavement considerably using the aforementioned method.
        4,600원
        23.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, halogen lamps for vehicle exterior lamp systems are being replaced by LEDs (Light Emitting Diode) in consideration of miniaturization, power consumption, life, luminance, and eco-friendliness. Due to regulations on the amount of light required, luminance, light uniformity, and glare prevention, it is required to develop a light guide for controlling a light source of an LED lamp for a vehicle. For the development of the light guides, the development of machining technology that can cut micro patterns of hundreds of micrometers scale into surface roughness of tens of nanometers scale must be preceded. In this study, the effect of variations in cutting conditions on surface roughness was analyzed through experiments. The micro patterns was manufactured by cutting into STAVAX material, and the surface of the micro patterns was super-finished using a ball-shaped PCD (polycrystalline diamond) tool without flutes. In experiments, the cutting conditions of the super-finishing process were varied, and the varied cutting conditions were feed rate, radial depth of cut, and spindle speed
        4,000원
        24.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the effects of ImmunoSEB as an immune-booster additive on the performance of broiler chicks. A total of 1150 broiler chickens were randomly allotted to three treatments on the basis of body weight (10 pens per treatment with 40 broilers in each pen): the control (CON), CON + ImmunoSEB 0.025% in feed (SEB25), and CON + ImmunoSEB 0.050% in feed (SEB50). The experiment was conducted for d 42 in three phases (phase 1, d 0–14; phase 2, d 15–28; and phase 3, d 29–42). There were significant differences in the average daily gain (ADG) and feed intake. The ADG at d 14 in the SEB50 treatment was greater than that in the CON treatment. The overall ADG in the SEB50 treatment was greater than that in the CON treatment. During d 0–14, the feed intake of chickens in the SEB50 treatment increased compared to that in the CON treatment. The crude protein and lysine digestibility improved in the SEB25 and SEB50 treatments compared to those in the CON treatment at d 28. Superoxide dismutase concentration significantly increased in the SEB50 treatment compared to that in the CON treatment. The interleukin-1β and tumor necrosis factor-α concentrations were higher in the cecum of chickens in the CON treatment than in the SEB25 and SEB50 treatments. A lower population of E. coli was detected in the ileum and cecum of broilers fed the SEB50 diet compared to those of broilers fed the CON diet. The overall result showed the beneficial effects of using ImmunoSEB at a dose of 0.050% in broiler chickens.
        4,200원
        28.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, the dynamics equations for a demolition fire vehicle were formulated. This was done by developing an interface that allows co-simulation using ADAMS and MATHEMATICA. In this study, MATHEMATICA alone was used to calculate the constrained dynamics equations, to demonstrate the impact force and the constraint Jacobian of the end-effector as any desired location through the x, y and z axes. Then we mathematically derived a model for a unilaterally constrained multi-link. Assumptions about the fire demolition vehicle of the constraint coordinate and the impact issues of the model are discussed in the next sections. The estimation procedure for the dynamics equation showed good approximation results in terms of solving a reaching task problem.
        4,000원
        29.
        2022.06 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 2021년 전남, 전북을 대상으로 23개소에서 어류 4종(향어, 비단잉어, 참붕어, 금붕어) 총 1,115마리에 대하여 병원체 감염 여부를 조사하였다. 법정전염병 3종(SVC, Spring viraemia of carp, EUS, Epizootic ulcerative syndrome, and KHVD, Koi herpesvirus disease)을 분 석한 결과, 조사한 모든 시료에서 법정전염병이 검출되지 않아 전라권에서 조사한 잉어과어 류는 청정국 또는 청정지역 선언에 중요한 정보를 제공할 것이다.
        4,000원
        31.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper aims to propose a new systematic approach to analyze the factor productivity and to investigate those characteristics of factor productivity in operational and managerial perspectives. The Cobb-Douglas production function is adopted to estimate the labor and capital productivity. In estimating those productivities the data of The Research on the Actual Condition of Coastal Fisheries (RACF), especially those of Jeon-Nam Province are used. The statistical analysis of RACF data shows that the characteristics are a little bit different between labor and capital of the operational equipment in the coastal fisheries. The Cobb-Douglas type production function is useful in estimating the factor productivity, especially in case of ‘coastal Stow-net fishery’ even though the limited data is used. However, in case of ‘trap fishery,’ the Cobb-Douglas production function appears to have some limitations in estimation. This implies that estimating the factor productivities in fisheries employing broad perspectives and various methods are needed.
        4,900원
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