• 제목/요약/키워드: Change Over Time

검색결과 2,177건 처리시간 0.03초

기후변화와 관련한 제주지역 농업용수의 효율적 활용 방안(I) (An Appropriate Utilization of Agricultural Water Resources of Jeju Island with Climate Change (I))

  • 송성호;최광준
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제17권2호
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    • pp.62-70
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    • 2012
  • Rainfall, on Jeju Island varies regionally in relation to Mt. Halla with higher rainfall within southern area and lower in western area, and its variability is expected to expand according to the climate change scenario. Non-parametric trend analysis for rainfall, using both historic (1971-2010) and simulated (2011-2100) data assuming the A1B emissions scenario, shows regionally increasing trends with time. In perspective of agricultural land use, area for market garden including various crop types with high water demand is increasing over the Island, especially in the western area with lower rainfall compared to southern area. On the other hand, area for fruit including mandarin and kiwi with low water demand is widely distributed over southern and northern part having higher rainfall. These regional disparity of water demand/supply may be more affected by extreme events such as drought and heavy rainfall that has not yet been considered. Therefore, it is necessary to make policies for water resource management considering both demand and supply in different regions with climate change impacts over Jeju Island.

표면 형상 변화에 따른 난류경계층 유동장 분석 (Transition of Turbulent Boundary Layer with a Step Change from Smooth to Rough Surface)

  • 이재화
    • 한국가시화정보학회지
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    • 제12권3호
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    • pp.15-20
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    • 2014
  • Direct numerical simulation (DNS) dataset of a turbulent boundary layer (TBL) with a step change from smooth to rough surface is analyzed to examine spatially developing flow characteristics. The roughness elements are periodically arranged two-dimensional (2-D) spanwise rods with a streamwise pitch of ${\lambda}=8k$ ($=12{\theta}_{in}$), and the roughness height is $k=15{\theta}_{in}$, where ${\theta}_{in}$ is the inlet momentum thickness. The step change is introduced $80{\theta}_{in}$ downstream from the inlet. For the first time, full images from the DNS data with the step change from the smooth to rough walls is present to get some idea of the geometry of turbulent coherent structures over rough wall, especially focusing on their existence and partial dynamics over the rough wall. The results show predominance of hairpin vortices over the rough wall and their spanwise scale growth mechanism by merging.

Monitoring changes in the genetic structure of Brown Tsaiya duck selected for feeding efficiency by microsatellite markers

  • Yi-Ying Chang;Hsiu-Chou Liu;Chih-Feng Chen
    • Animal Bioscience
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    • 제36권3호
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    • pp.417-428
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    • 2023
  • Objective: Few studies have genetically monitored chickens over time, and no research has been conducted on ducks. To ensure the sustainable management of key duck breeds, we used microsatellite markers to monitor Brown Tsaiya ducks over time genetically. Methods: The second, fourth, sixth to eighth generations of the Brown Tsaiya duck selected for feeding efficiency and control lines were included in this study to investigate the genetic variations, effective population size, population structure and the differentiation between populations over time with 11 microsatellite markers derived from Brown Tsaiya duck. Results: The results showed there were a slight decrease in the genetic variations and an increase in within-population inbreeding coefficient (FIS) in both lines, but no consistent increase in FIS was observed in each line. The effective population size in the second and eighth generations was 27.2 for the selected line and 23.9 for the control line. The change in allele richness showed a downward trend over time, and the selected line was slightly lower than the control line in each generation. The number of private alleles (Np) in the selected line were higher than in the control line. Moderate differentiation was observed between the second and eighth generations in the selected line (FST = 0.0510) and the control line (FST = 0.0606). Overall, differentiation tended to increase with each generation, but genetic variation and structure did not change considerably after six generations in the two lines. Conclusion: This study provides a reference for poultry conservation and helps to implement cross-generation genetic monitoring and breeding plans in other duck breeds or lines to promote sustainable management.

Effects of Spatial Distribution on Change Detection in Animated Choropleth Maps

  • Moon, Seonggook;Kim, Eun-Kyeong;Hwang, Chul-Sue
    • 한국측량학회지
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    • 제32권6호
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    • pp.571-580
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    • 2014
  • To address unsolved issues of change detection in animated choropleth maps, we proposed the concept of 'gross change detection' and performed an experiment that empirically verifies the incidence of change blindness stems from the 'magnitude of change (MOC)', spatial distribution in animated choropleth maps. We generated experimental materials using the change-characterization arrays and the global Moran's I. Participants had 108 cases of changing maps with time duration (1 to 3 sec) and had questions. The results showed that MOC and duration affect gross change detection, but the most interesting result from our experiment was that different spatial distributions between two adjacent choropleth maps may lead the map reader to under- or over-estimate the level of gross change in the map. It implies that we should consider spatial distribution of change when we design animated choropleth maps.

Diversity, Evolution & Marketing Practice

  • Murray, John A.;Torres, Ann M.
    • 마케팅과학연구
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    • 제7권
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    • pp.71-103
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    • 2001
  • Marketing practice varies among firms. However, the prescriptive literature emphasises a universal view of practice, a 'one size fits all' view. This paper addresses the issue of explaining diversity in marketing practice in competitive space and in time. Diversity in competitive space reflects the existence of different routes to high performance. Diversity in time reflects some combination of change in the individual firm and change in a population of firms. In the former case, diversity is shaped by organisational change; in the latter by the disbandment and founding of firms in the population. In so far as diversity is the norm, the manner in which practice will be shaped by evolutionary processes is considered. Fnally, the role of the academy as one of the forces driving the evolutionary process is discussed. Miles and Snow's (1978, 1986) work is taken as a main point of departure in the search for explanation and ecological and evolutionary concepts are drawn on for support and to suggest an explanation for the nature of diversity over time.

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Shear Layer and Wave Structure Over Partially Spanning Cavities

  • Das, Rajarshi;Kim, Heuy Dong;Kurian, Job
    • 한국가시화정보학회지
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    • 제11권2호
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    • pp.46-54
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    • 2013
  • Study of the wave structure and shear layer in the vicinity of a wall mounted cavity is done by time averaged colour schlieren and time resolved instantaneous shadowgraph technique in an M=1.7 flowfield. Effect of change of cavity width on flow structure is investigated by using constant length to depth (L/D) ratio cavity models with varying length to width (L/W) ratio of 0.83 to 4. The time averaged shock wave structure was observed to change with change in cavity width. Dependence of the shock angle at the leading edge on the shear layer width is also evident from the images obtained. Unsteadiness in the flow field in terms of shear layer dynamics and quasi steady nature of shock waves was evident from the images obtained during instantaneous shadowgraph experiments. Apart from the leading and trailing edge shocks, several other waves and flow features were observed. These flow features and the associated physical phenomena are discussed in details and presented in the paper.

60세이상 노인의 신체 부위별 전기자극시간에 따른 역치 변화에 대한 연구 (A Study on the Influence of Change of Electrical Stimulation Time on Body Regions Affects on Threshold of People Over Age 60)

  • 이재갑;최정현
    • 대한물리치료과학회지
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    • 제16권4호
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    • pp.29-37
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    • 2009
  • Background: The purpose of this study was influence of change of electrical stimulation time on body regions affects on electrical current threshold. Methods: The present study is to examine the effect of silver spike point (SSP) electrical stimulation (1Hz), transcutaneous electrical nerve stimulation (TENS, 100Hz), and interferential current therapy (ICT, 50Hz) from the low back and scapulodorsal and knee joint regions on stimulation-induced current thresholds from the elderly (over sixty) people (male:72, female:91) in senior welfare center. Result: The low back region, but not scapulodorsal and knee joint region, significantly increased the TENS and ICT, but not SSP, electrical stimulation, significantly increased the time-dependent current thresholds in elderly patients. Conclusion: Therefore, these results, in part, suggest that the TENS and ICT were shown to be a more adaptable method of stimulation, and that needed of the development of senile specialized physical therapy and the utilization of senior leisure facilities such as senior welfare center the others.

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NAS 전지 모듈의 온도 분포 특성에 관한 연구 (A Study on the Temperature Distribution Characteristics of NAS Battery Module)

  • 허두상;이중섭;정효민;정한식
    • 한국기계가공학회지
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    • 제11권4호
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    • pp.1-6
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    • 2012
  • This paper addresses the issue of Renewable Energy for Electricity Storage device is one of the NAS (Sodium-Sulfur) battery will be about the module. For safety reasons, not the actual battery cells using a dummy cell in the module's operating temperature setting to examine the characteristics of the insulation vacuum of the wall temperature and external temperature changes measured over time. Upper and lower boundaries of the wall vacuum insulation characteristics cotton C intervals over time, average $5^{\circ}C$, but the temperature is rising, 4C section with little temperature change did not occur. On the other hand, about $3^{\circ}C$ in section 4D, and it was confirmed that the temperature rises. Wall vacuum insulation characteristics over time to look at the experiments and measurements are described.

현상액의 사용 시일 경과에 따른 필름 특성의 변화 (THE CHANGE OF FILM CHARACTERISTICS ACCORDING TO THE PROCESS OF USING TIME OF PROCESSING SOLUTION)

  • 정문성;정현대
    • 치과방사선
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    • 제22권1호
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    • pp.128-136
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    • 1992
  • This study was undertakened to investigate the change of image characteristics on dental films according to the process of using time of processing solution in automatic processor. Base + fog density, film density and subject contrast were measured with the digital densitometer, the pH of developing and fixing solution were measured with Digital pH / ION Meter. The following results were obtained: 1. Base + fog density was increased with the process of using time of the processing solution and was over the maximum permissible base + fog density 0.25 from the 3rd day. 2. Film density was increased with the process of using time of the processing solution. 3. Subject contrast was decreased with the process of using time of the processing solution. 4. The pH of the developing solution was decreased with the process of using time, the pH of the fixing solution was increased.

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Analytic consideration on real-time assembly line control for multi-PCB models

  • Um, Doo-Gan;Park, Jong-Oh;Cho, Sung-Jong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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    • pp.318-323
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    • 1992
  • The improvement of the production capability of multi PCB assembly line can not be simply done by improving the capacities of each assembly robot cells but must be done by controlling the production line effectively with the line host computer which controls over the whole assembly line. A real time production control, a real time model change and a real time trouble shooting compose the specific concepts of this technique. In this paper, we present and analyze the definition and application method of real time assembly concept. The meaning of real time model change, troubles and error sooting and its algorithm will be introduced. Also, the function of the host computer which is in charge of all of many different tasks mentioned above and the method are presented. The improvement of the productivity is mainly focused on the efficiency of multi-PCB production control. The importance of this aspect is gradually increasing, which we have presented the analysis and the solution.

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