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        검색결과 2,484

        721.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 물때에 따른 교통특성을 분석하여 선박통항관리 개발에 필요한 자료를 제공하고자 한다. 목포항의 1년간 선박자동식별장치 자료를 사용하였다. 물때에 따른 교통량을 분석하기 위해 목포항의 1년간의 선박자동식별장치의 양력 데이터를 음력으로 변환한 후, 서해안의 구전 물때를 적용하였다. 연구 결과, 출항선박은 2-3물때 교통량이 7물때 보다 약 23-24% 많고, 입항선박은 12-13물때 교통량이 9물때 보다 약 29-33 % 많았다. 특히, 시간의 변화에 따른 물때별 변동지수는 sine 함수의 형태로 변화하였다. 본 연구는 물때에 따른 선박통항관리 개발에 필요한 기초자료로 활용될 수 있을 것으로 판단된다.
        4,000원
        723.
        2015.10 구독 인증기관 무료, 개인회원 유료
        The single vendor single buyer integrated production inventory problem with lead time proportional to lot size and space restriction is studied. Demand is assumed to be stochastic and the continuous review inventory policy is used for the buyer. If the buyer places an order with lots of products, then the vendor will produce lots of products and the products will be transferred to the buyer with equal shipments many times. Mathematical model for this problem is defined and a Lagrangian relaxation approach is developed.
        3,000원
        731.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 신품종 다래‘오텀센스’의 수확적기를 구명하고자 생육시기별 과실품질과 후숙 특성을 조 사하였다. 과실의 후숙은 과실의 비대가 최대가 되고 과실 내 종자가 성숙한 이후에 가능하였으나, 종 자가 성숙 상태만으로는 후숙 가능성을 판단할 수 없었다. 산함량은 1.05%이상이 되어야 정상적인 후 숙이 진행되었으며 후숙이 가능한 시점의 경도는 평균 27.1N이었다. 성숙기에 접근한 과실의 가용성 고 형물 함량은 만개후 71일부터 90일까지 시기별로 유의적인 차이가 없었지만 후숙 후의 가용성 고형물 함량에는 유의적 차이가 있어 가용성 고형물 함량으로 수확적기를 구명하기에는 어려움이 있었다. 다래 의 저장 중 중량감소율은 2℃에 상대습도 90%저장구가 낮았고, 부패율은 20℃, 상대습도 45% 저장구 에서는 저장 8일 후부터 증가하기 시작하였고, 2℃에 상대습도 45%와 상대습도 90% 모두 저장 후 20 일까지 10% 이하로 유지되었다. 따라서 과실의 크기, 경도 및 후숙 전·후의 가용성 고형물 함량 등을 종합하여 고려해 볼 때 신품종 다래‘오텀센스’의 수확적기의 만개 후 생육일수는 85일(9월 2일)이었 고, 2℃에 상대습도 90%인 저온고습환경이 적합하였다.
        4,000원
        732.
        2015.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        MAO ceramic coatings were prepared on AZ61 magnesium alloy for various processing times ranging from 5 to 60 min, in an electrolyte solution based on silicate-fluoride. The mechanical, electrochemical and, microstructural properties and the phase compositions of the coating layers were investigated. In this work, unlike previous studies, coatings with high amounts of the Mag2SiO4 phase were formed which contained small amounts of MgO and MgF2 at a processing condition of 30 min. A microstructural analysis revealed that the porosity of the coatings was reduced considerably with an increase in the processing time, together with a change in the pore geometry from an irregular to a spherical shape. Potentiodynamic polarization and mechanical testing results showed that the coatings acquired after a processing time of 30 min were superior to all of the others.
        4,000원
        733.
        2015.10 구독 인증기관·개인회원 무료
        Purpose: This study was to assess the influence of silicone hydrogel contact lenses wearing time on corneal higher-order aberrations (HOAs), visual performance, and subjective ocular symptoms. Methods: Thirty subjects took part in this study. Subjects were fitted with silicone hydrogel contact lenses (Biofinity). Best-corrected visual acuity (VA) at two contrast levels (100% and 10%) and best-corrected contrast sensitivity (CS) for four spatial frequencies (3, 6, 12, and 18 cycles per degree) were measured under photopic and mesopic conditions. Corneal HOAs were measured with 4-mm and 6-mm pupils using Wavefront Analyzer. All measurements were performed respectively after 2 hours and 9 hours wear with the silicone hydrogel lenses during a day. Subjects were asked by a study examiner to complete the questionnaire for contact lens-related subjective ocular symptoms. Results: Data for this study were employed for fifty-four eyes (27 subjects; 14 females, 13 males) and the subjects were 24.30 ± 2.96 years. For the subjects, current or previous experience with contact lenses was 23 subjects and non-experience with contact lenses was 4 subjects. Regarding visual quality under photopic and mesopic conditions, there was no statistically significant difference in high contrast and low contrast visual acuity as well as contrast sensitivity between 2 hours and 9 hours wear. For corneal HOAs, we also did not find any significant changes in total HOAs, third-order, fourth-order, coma, and spherical aberration for both 4-mm and 6-mm pupils between the two wearing time. In the relative frequency of contact lens-related subjective ocular symptoms, there were statistically differences in discomfort, dryness, and closing eyes between 2 hours and 9 hours wear within the brand (p=0.031, p=0.001, and p=0.031, respectively) (after 9 hours of the lens wear, discomfort (52%), dryness (74%), and closing eyes (56%)); however, there were no significant differences in changeable vision and removing lenses between the two wearing time. Conclusions: Silicone hydrogel contact lenses used this study do not reduce optical quality of the eye and visual quality after nine hours of the contact lens wear during a day. However, the majority of soft contact lens wearers still encounter clinically significant ocular symptoms including discomfort and dryness with the silicone hydrogel lenses.
        734.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of time-frequency analysis techniques allow astronomers to successfully deal with the non-stationary time series that originate from unstable physical mechanisms. We applied a recently developed time-frequency analysis method, the Hilbert-Huang transform (HHT), to two non-stationary phenomena: the superorbital modulation in the high-mass X-ray binary SMC X-1 and the quasi-periodic oscillation (QPO) of the AGN RE J1034+396. From the analysis of SMC X-1, we obtained a Hilbert spectrum that shows more detailed information in both the time and frequency domains. Then, a phase- resolved analysis of both the spectra and the orbital profiles was presented. From the spectral analysis, we noticed that the iron line production is dominated by different regions of this binary system in different superorbital phases. Furthermore, a pre-eclipse dip lying at orbital phase ~ 0.6 - 0.85 was discovered dur- ing the superorbital transition state. We further applied the HHT to analyze the QPO of RE J1034+396. From the Hilbert spectrum and the O - C analysis results, we suggest that it is better to divide the evolu- tion of the QPO into three epochs according to their different periodicities. The correlations between the QPO periods and corresponding uxes were also different in these three epochs. The change in periodicity and the relationships could be interpreted as the change in oscillation mode based on the diskoseismology model.
        3,000원
        735.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present the results from analysis of the Hilbert-Huang transform (HHT) for the 4 Hz quasi-periodic oscillations (QPO) around the black hole X-ray binary XTE J1550-564. The resultant Hilbert spectra demonstrate that the QPO is composed of a series of intermittent signals appearing occasionally. From the analysis of the HHT, we further found the distribution of the lifetimes for the intermittent oscillations and the distribution for the time intervals with no significant signal (the break time). The mean lifetime is 1.45 s and 90% of the oscillation segments have lifetimes less than 3.1 s whereas the mean break time is 0.42 s and 90% of break times are less than 0.73 s. We conclude that the intermittent feature of the QPO could be explained by the Lense-Thirring precession model and rules out interpretations of continual frequency modulation.
        3,000원
        736.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investigated the long term variability of the intensities of the broad-line region emission lines in the UV spectra of Seyfert I galaxy NGC 5548 from 1973-1996. We have obtained the following results: 1) a high level correlation between the intensities of emission lines as well as between intensities of emission lines and continuum uxes was discovered. With increasing wavelength the correlation in both cases becomes weaker, 2) the relationship between the intensity of emission lines and the ux radiation in the continuum can be expressed by a power law function with coefficients of α ≈ 0:8 - 1:1 for different lines. When the difference between the wavelengths of spectral lines and the continuum is increased, the value of the power function decreases, and 3) it was found that the magnitude of the variability of the line intensities are weaker than the range of variability of the continuum uxes. The magnitude of the variability of the line intensities and the continuum uxes increase at longer wavelengths.
        3,000원
        737.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        절화용 국산 스프레이 장미의 정식 후 1차 절곡시기와 2차 절곡방법이 절화품질 및 생산성에 미치는 영향을 조사하였다. 적심 후 절곡시기까지의 경과일수가 길어질수록 주당 엽수, 줄기수, 줄기 굵기 및 1차 측지수가 증가되었다. 특히 ‘White Zen’, ‘Glory Purple’ 및‘Live Pink’는 적심 25일 이후에 충분한 엽수가 확보되었다. 품종별 개화는 절곡시기가 늦어질수록 빨라졌고, 절화장, 마디수와 7매엽은 시험품종 모두 절곡시기가 늦어질수록 우수해지는 경향이었다. 1차 절곡 후 발생한 줄기수는 절곡시기가 늦어질수록 많았으나, 상품 줄기수와수출 가능한 줄기수는 적뢰 25-35일 후 절곡처리에서 대체로 높았다. 2차 절곡방법에 따른 절화장, 소화수 및 줄기 굵기 등의 절화품질은 1차 절곡 후 발생한 줄기 중상품성 있는 줄기 1본을 수확하고 나머지를 절곡한 처리(T2)가 모두 절곡한 처리(T3, T4)보다 우수하거나 유사하였고, 상품성 있는 줄기를 모두 수확하고 비상품 줄기만 절곡한 처리(T1)에서 저조하였다. 상품성 줄기와 수출 가능한 줄기수는 T1 처리가 낮았고 나머지 처리는 유사하였으며, 1차 절곡 후 발생한 상품성 있는 줄기 1본을수확하는 T2 처리가 적절한 2차 절곡방법이라고 생각된다.
        4,000원
        738.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The incidents related to transporting hazardous materials may cause serious impacts on neighborhood and surrounding areas. It is essential to have a real-time safe management system for incidents prevention of transporting hazardous materials. Currently, the system is not integrated into one channel, which makes it difficult to control an incidents response. Another problem is that event status is not appropriately shared among authorities having responsibilities taking down the incidents. This paper investigates previous studies covering the real-time safety management system for hazard material transports and suggests an integrated management system that helps communicate effectively and promptly.
        4,000원
        739.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Objective : This study examined the impact of a sixteen-week time-use intervention perio on the depression and rehabilitation motivation of stroke patients with psychological difficulties.Methods : Ten stroke patients who were divided into an experimental group and a control group participated in this study from May 2014 to August 2014. Depression changes were measured using a Beck Depression Inventory (BDI), and their rehabilitation motivation was evaluated using the Rehabilitation Motivation Scale.Results : The results of the present study showed that the experimental group and control group presented significant differences before and after intervention in terms of their depression and rehabilitation motivation. However, after intervention, the depression and rehabilitation motivation did not differ between the two groups.Conclusion : The results of this study indicate that time-use intervention was effective in improving the depression and rehabilitation motivation of stroke patients, and therefore time-use intervention with occupational therapy will be useful as a clinical method for improving their level of depression and rehabilitation motivation.
        4,500원
        740.
        2015.09 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 대두(soybean)의 외관 검사를 위해 명암도, 지역분산 및 지역 명암도 차이에 기초한 대두 선 별 알고리즘과 이를 적용한 대두 선별 장치의 구현 방법을 제안한다. 제안한 선별 장치는 4개의 채널로 구분된 벨트 컨베이어를 이용하여 대두 시료를 정렬된 형태로 이송하고, 종단에서 낙하하는 대두들에 대해 배후조명(back-light)과 흑백의 라인스캔(line-scan) 카메라를 이용하여 영상을 획득한 후 실시간으로 대두의 외관을 양품과 불량으로 선별하 였다. 실시간 선별을 위해서 각 채널별로 전용의 DSP를 사용하였으며, 각각의 DSP에서는 채널별로 얻은 대두 영상 으로부터 명암도, 명암도의 지역분산, 지역명암도 차이에 기초하여 양품으로부터 얻은 10개의 판별 문턱치와 대두 클 래스별 3개의 특징벡터를 찾아 4개의 클래스로 구분된 대두 영상에 대한 양품과 불량 선별을 실시하였다. 선별 결과 처리량은 약 520kg/hour였고, 양품 선별 정확도 즉, 양품에 대한 양품 인식률은 97%이며 불량 선별 오류, 즉 불량을 양품으로 인식하는 비율은 4.3%를 나타냈다.
        4,300원