• Title/Summary/Keyword: time variability

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Seismic Behavior of Bridges Considering Ground Motion Spatial Variation (공간적으로 변화하는 입력지진으로 인한 교량의 지진거동특성)

  • Bae, Byung Ho;Choi, Kwang Kyu;Kang, Seung Woo;Song, Si Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.4
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    • pp.759-768
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    • 2015
  • The ground motions of large dimensional structures such as long span bridges at different stations during an earthquake, are inevitably different, which is known as the ground motion spatial variation effect. There are many causes that may result in the spatial variability in seismic ground motion, e.g., the wave passage effect due to the different arrival times of waves at different locations; the loss of coherency due to seismic waves scattering in the heterogeneous medium of the ground; the site amplification effect owing to different local soil properties. In previous researches, the site amplification effects have not been considered or considered by a single-layered soil model only. In this study, however, the ground motion amplification and filtering effects are evaluated by multi-layered soil model. Spatially varying ground motion at the sites with different number of layers, depths, and soil characteristics are generated and the variation characteristics of ground motion time histories according to the correlation of coherency loss function and soil conditions are evaluated. For the bridge system composed of two unit bridges, seismic behavior characteristics are analyzed using the generated seismic waves as input ground motion. Especially, relative displacement due to coherency loss and site effect which can cause the unseating and pounding between girders are evaluated. As a result, considering the soil conditions of each site are always important and should not be neglected for an accurate structural response analysis.

Effects of Climatic Condition on Stability and Efficiency of Crop Production (농업 기상특성과 작물생산의 효율 및 안전성)

  • Robert H. Shaw
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.27 no.4
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    • pp.296-313
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    • 1982
  • At a time when world population and food supply are in a delicate balance, it is essential that we look at factors to improve this balance. We can alter the environment to better fit the plant's needs, or we can alter the plant to better fit the environment. Improved technology has allowed us to increase the yield level. For moderately detrimental weather events technology has generally decreased the yield variation, yet for major weather disasters the variation has increased. We have raised the upper level, but zero is still the bottom level. As we concentrate the production of particular crops into limited areas where the environment is closest to optimum, we may be increasing the risk of a major weather related disaster. We need to evaluate the degree of variability of different crops, and how weather and technology can interact to affect it. The natural limits of crop production are imposed by important ecological factors. Production is a function of the climate, the soil, and the crop and all activities related to them. In looking at the environment of a crop we must recognize these are individuals, populations and ecosystems. Under intensive agriculture we try to limit the competition to one desired species. The environment is made up of a complex of factors; radiation, moisture, temperature and wind, among others. Plant response to the environment is due to the interaction of all of these factors, yet in attempting to understand them we often examine each factor individually. Variation in crop yields is primarily a function of limiting environmental parameters. Various weather parameters will be discussed, with emphasis placed on how they impact on crop production. Although solar radiation is a driving force in crop production, it often shows little relationship to yield variation. Water may enter into crop production as both a limiting and excessive factor. The effects of moisture deficiency have received much more attention than moisture excess. In many areas of the world, a very significant portion of yield variation is due to variation in the moisture factor. Temperature imposes limits on where crops can be grown, and the type of crop that can be grown in an area. High temperature effects are often combined with deficient moisture effects. Cool temperatures determine the limits in which crops can be grown. Growing degree units, or heat accumulations, have often been used as a means of explaining many temperature effects. Methods for explaining chilling effects are more limited.

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Non-stationary Frequency Analysis with Climate Variability using Conditional Generalized Extreme Value Distribution (기후변동을 고려한 조건부 GEV 분포를 이용한 비정상성 빈도분석)

  • Kim, Byung-Sik;Lee, Jung-Ki;Kim, Hung-Soo;Lee, Jin-Won
    • Journal of Wetlands Research
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    • v.13 no.3
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    • pp.499-514
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    • 2011
  • An underlying assumption of traditional hydrologic frequency analysis is that climate, and hence the frequency of hydrologic events, is stationary, or unchanging over time. Under stationary conditions, the distribution of the variable of interest is invariant to temporal translation. Water resources infrastructure planning and design, such as dams, levees, canals, bridges, and culverts, relies on an understanding of past conditions and projection of future conditions. But, Water managers have always known our world is inherently non-stationary, and they routinely deal with this in management and planning. The aim of this paper is to give a brief introduction to non-stationary extreme value analysis methods. In this paper, a non-stationary hydrologic frequency analysis approach is introduced in order to determine probability rainfall consider changing climate. The non-stationary statistical approach is based on the conditional Generalized Extreme Value(GEV) distribution and Maximum Likelihood parameter estimation. This method are applied to the annual maximum 24 hours-rainfall. The results show that the non-stationary GEV approach is suitable for determining probability rainfall for changing climate, sucha sa trend, Moreover, Non-stationary frequency analyzed using SOI(Southern Oscillation Index) of ENSO(El Nino Southern Oscillation).

Environmental factors affecting roost use of shorebirds in the southern Kanghwa Island, Republic of Korea (강화도 남단에 도래하는 도요새들의 해안 내륙 휴식지 이용과 이들의 이용에 영향을 미치는 환경요인들)

  • Kim, Kwan Mok;Moon, Young Min;Yoo, Jeong Chil
    • Journal of Wetlands Research
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    • v.15 no.2
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    • pp.251-264
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    • 2013
  • There are some factors affecting the shorebirds in selecting a coastal inland roost site where they have to stay during the high tide when the entire intertidal zone is covered with water. We investigated eight species (Eastern Curlews Numenius madagascariensis, Green Shanks Tringa nebularia, Bar-tailed Godwits Limosa lapponica, Grey Plovers Pluvialis squatarola, Dunlins Calidris alpine, Whimbrels Numenius phaeopus, Eurasian Curlews Numenius arquata and Terek Sandpipers Xenus cinereus) to identify the spatial and temporal variability in coastal inland roost use in the area and the factors influencing the use. We considered the area and length of the standing water in the roost site, temperature, wind speed, the time of migration and the intensity of disturbance. As a result, number of individuals and type of species using the roost site varied across spatial and temporal scales. And the factors affecting the roost use was species-specific. The roost site of the study area was a closed shrimp farm however, it has been converted to a Salicornia herbacea, a salt marsh plant, farm recently. In a situation where coastal inland roost site is needed, we hereby describe a resolution for the juxtaposition of shorebirds and farming.

NIRS ANALYSIS OF MOLASSES AND EATS USED AT THE ANIMAL FEEDS INDUSTRY

  • Garrido-Varo, Ana;Perez-Marin, Maria Dolores;Gomez-Cabrera, Augusto;Guerrero-Ginel, Jose Emilio;Paz, Felix De;Delgado, Natividad
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1613-1613
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    • 2001
  • Fats and molasses are used, at the present time, in a considerable proportion as ingredients for the animal feed industry. They are mainly used as energy sources, but also they provide other characteristics of technological and nutritional interest (dust reduction, increase in palatability, etc). Both semi-liquid ingredients have numerous aspects in common from the point of view of their use in livestock feeds, as well as of their analytical control. Feed manufacturers use several criteria to evaluate the quality of fat and molasses. Furthermore, the traditional methods currently used, for their evaluation (eg. fatty acids, sugars, etc) are expensive and more sophisticated that the traditionally used for solid ingredients. The objective of the present work is to carry out a viability study to evaluate the ability of NIRS technology for the quality control of fat and molasses. Samples of liquid molasses (n = 42) and liquid fat ( n = 61), provided by a feed manufacturer, were scanned in a FOSS-NIR Systems 6500 monochromator equipped with a spinning module. The samples were analysed by folded transmission, using a sample cup of 0.1mm pathlength and gold surface reflector. For molasses, calibration equations were developed for the prediction of moisture (SECV=1.69%; $r^2$=0, 42), gross protein (SECV=0, 14%; $r^2$=0, 99), ashy (SECV=0, 60%; $r^2$=0, 84), NaCl (SECV=0, 05%; $r^2$=0, 99) and sugars (SECV=1, 04%; $r^2$=0, 86). For animal fats calibrations were obtained for the prediction of moisture (SECV=0, 14%, $r^2$=0, 88), acidity index (SECV=0, 83%, $r^2$=0, 82), MIU (SECV=0, 38%, $r^2$=0, 94) and unsaponifiables (SECV=0, 45%, $r^2$=0, 87). High accuracy calibration equations were also obtained for the prediction of the fatty acid profile. The equations have $r^2$values around 0.9 or highest. The results showed that NIRS technology could provide rapid and accurate results and reduce analytical costs associated to the quality control of two Important feed ingredients of a well known chemical variability.

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NIR-TECHNOLOGY FOR RATIONALE SOIL ANALYSIS WITH IMPLICATIONS FOR PRECISION AGRICULTURE

  • Stenberg, Bo
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1061-1061
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    • 2001
  • The scope of precision agriculture is to reach the put up cultivation goals by adjusting inputs as precise as possible after what is required by the soil and crop potentials, on a high spatial resolution. Consequently, precision agriculture is also often called site specific agriculture. Regulation of field inputs “on the run” has been made possible by the GPS (Geographical Position System)-technology, which gives the farmer his exact real time positioning in the field. The general goal with precision agriculture is to apply inputs where they best fill their purpose. Thus, resources could be saved, and nutrient losses as well as the impact on the environment could be minimized without lowering total yields or putting product quality at risk. As already indicated the technology exists to regulate the input based on beforehand decisions. However, the real challenge is to provide a reliable basis for decision-making. To support high spatial resolution, extensive sampling and analysis is required for many soil and plant characteristics. The potential of the NIR-technology to provide rapid, low cost analyses with a minimum of sample preparation for a multitude of characteristics therefore constitutes a far to irresistible opportunity to be un-scrutinized. In our work we have concentrated on soil-analysis. The instrument we have used is a Bran Lubbe InfraAlyzer 500 (1300-2500 nm). Clay- and organic matter-contents are soil constituents with major implications for most properties and processes in the soil system. For these constituents we had a 3000-sample material provided. High performance models for the agricultural areas in Sweden have been constructed for clay-content, but a rather large reference material is required, probably due to the large variability of Swedish soils. By subdividing Sweden into six areas the total performance was improved. Unfortunately organic matter was not as easy to get at. Reliable models for larger areas could not be constructed. However, through keeping the mineral fraction of the soil at minimal variation good performance could be achieved locally. The influence of a highly variable mineral fraction is probably one of the reasons for the contradictory results found in the literature regarding organic matter content. Tentative studies have also been performed to elucidate the potential performance in contexts with direct operational implications: lime requirement and prediction of plant uptake of soil nitrogen. In both cases there is no definite reference method, but there are numerous indirect, or indicator, methods suggested. In our study, field experiments where used as references and NIR was compared with methods normally used in Sweden. The NIR-models performed equally or slightly better as the standard methods in both situations. However, whether this is good enough is open for evaluation.

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COMPARISON OF THE TREATMENT EFFECTS BETWEEN MEDICATION ONLY AND MEDICATION-PLUS-PARENT TRAINING IN ADHD CHILDREN (주의력결핍 과잉활동 장애 아동에서 약물 단독 치료와 부모 훈련 병합 치료의 효과 비교)

  • Shin, Min-Sup;Oh, Kyung-Ja;Hong, Kang-E
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.6 no.1
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    • pp.65-73
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    • 1995
  • We conducted the comparative study of the effects of the parent training combined with medication and the medication only on 23 ADHD children with the age from 5 to 11(body 22, girl 1). Mothers of combined treatment group(parent training+medication) attended, the parent training program once a week for 8 consecutive weeks and booster session 1 month later. Children of both groups were assessed twice before and after treatment using the various using scales and TOVA to evaluate the treatment effects. The results of present study showed the greater effectiveness of the medication+parent training over the medication only in reducing the parenting stress of mothers as well as the inattention and behavioral problems of ADHD children. In medication only group while the scores of mother's rating did not change significantly after treatment, those of teacher's rating and TOVA tend to be decreased to normal range. These results suggested that methylphenidate is effective on improving attentional problems of ADHD children, but not on behaviral problems at home. These results mean that parent training is needed for reducing behavioral problems of ADHD children, negative interactions in mother-child relation, and parenting stress as well as maxmizing medication effect.

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COGNITIVE CHARACTERISTICS OF CHILDREN WITH DYSLEXIA AND/OR ATTENTION DEFICIT/HYPERACTIVITY DISORDER (읽기 장애 아동과 주의력 결핍/과잉 활동장애 아동의 인지적 특성)

  • Kim, Seung-Tai;Kim, Ji-Hae
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.7 no.2
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    • pp.224-232
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    • 1996
  • The present study was conducted to investigate cognitive characteristics of children with dyslexia and/or attention deficit/hyperacidity disorder. Cognitive characteristics were evaluated by using KEDI-WISC, the Basic Achievement Test, TOVA, MFFT, and neuropsychological tests. ADHD group showed significantly lower level of performance in response time for correct responses and presented variability for correct responses in TOVA. Dyslexia and mixed group showed lower performance in Reading I and Reading II, Writing subtest in the Basic Achievement Test than those of ADHD group and in Information subtest of KEDI-WfSC. In order rd determine the diagnostic effectiveness of each psychological tests, discriminant analysis was conducted. In this analysis, 11 subtests of KEDI-WISC and 4 variables of TOVA, 4 subtests of the Basic Achievement Test, and MFFT, WCST were included as independent variables and each diagnostic roups were dependent variables. Discriminant analysis indicated that overall percentage of correct classification was 93.88%. The clinical implifications and limitations of the present study were listed and discussed.

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Evaluation of Peri-procedural Anticoagulation Drug Therapy undergoing Radiofrequency Ablation in Patients with Atrial Fibrillation (심방세동 환자의 고주파 도자절제술 전.후의 항응고약물요법 사용실태 분석)

  • Kim, Su-Hyun;An, Sung-Shim;Kim, Soon-Joo;Bang, Joon-Seok;La, Hyen-Oh
    • Korean Journal of Clinical Pharmacy
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    • v.20 no.2
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    • pp.159-164
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    • 2010
  • Radiofrequency ablation (RA) is being used to manage atrial fibrillation (AF) with patients failed at the $1^{st}$-line anti-arrhythmic medications. Patients undergoing this procedure are at increased risk of thromboembolism after ablation, and anticoagulation management surrounding the ablation remains controversial. Although no conclusive recommendations can be made, published guidelines and data support therapeutic anticoagulation with warfarin. The purpose of this study was to analyze effectiveness of current therapy and to find factors fluctuate International Normalized Ratio (INR) values in patients undergone RA followed by anticoagulation service (ACS). Retrospective review was conducted utilizing database in a hospital. Among 110 patients under warfarin around ablation between January 2006 to September 2007, 54 patients were selected and allocated into 2 groups: Group A included 47 who discontinued warfarin after ablation, while 7 in B continued the medication. Information on demographics, amount and length of warfarin dosing, INR values and measuring frequencies, and the causing factors on INR fluctuation were abstracted. Differences were analyzed using chi-squared test, Fisher's Exact test, and unpaired Student t-test. Mean amount of warfarin before and after surgery was 4.0 mg, 4.1 mg in Group A and was 5.1 mg, 4.6 mg in Group B, respectively. Average duration of warfarin doing before ablation was 73.7 days in Group A, 129.9 days in B with no significant difference (p = 0.312). The duration time of warfarin on groups after ablation lasted several months. The number of checking INRs was 4.1 and 7.6, respectively. Inter-individual variability of INR fluctuations were $2.1{\pm}0.6$ in Group A and $2.2{\pm}0.7$ in B which were not significantly different (p = 0.062). 164 cases of decreased INR were: 'omission in taking medication, stressfulness and headache, 'increased intake of high vitamin K foods', 'lifestyle change of increased physical activities', and 'increase of food-intakes'. To the contrary, 36 cases of increased INR were: 'reduce of food-intake', 'use of non-prescription drugs', 'reduction in physical activities', and 'excessive restriction on food-intake', consecutively. In conclusion, the study validated therapeutic outcomes of RA patients who we treated with standard guideline and demonstrated 9 factors of INR fluctuations in the patient. A well-trained, pharmacist-monitored anticoagulation service could reduce the risk of adverse effects and prevent complications in patients with AF around RA operation.

An Approach to Managing Requirements as a Core Asset in Software Product-Line (소프트웨어 프로덕트 라인에서 핵심 자산으로서 요구사항을 관리하는 방법)

  • 문미경;염근혁
    • Journal of KIISE:Software and Applications
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    • v.31 no.8
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    • pp.1010-1026
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    • 2004
  • The goal of product line engineering is to support the systematic development of a set of similar software systems by understanding and controlling their common and distinguishing characteristics. The product line engineering is a process that develops reusable core assets and develops a set of software-intensive systems from a common set of core assets in a prescribed way. Currently, many software development technologies are accomplished in context of product line. However, much of the product line engineering research have focused on the reuse of work products relating to the software's architecture, detail design, and code. The product lines fulfill the promise of tailor-made systems built specifically for the needs of particular customers or customer groups. In particular, commonality and variability play central roles in the all product line development processes. These must be treated already during the requirement analysis phase. Requirements in product line engineering are basis of software development just like as traditional system development engineering, and basis of deciding other core assets' property - commonalities and variabilities. However, it is difficult to elicit, analyze and manage correct requirements. Therefore, it is necessary to develop systematic methods which can develop and manage requirement as core asset, which can be stable in anticipative change and can be well adapted to unpredictable change. In this paper, we suggest a method of managing requirements as core asset in product line. Through this method, the reuse of domain requirements can be enhanced. As a result, the cost and time of software development can be reduced and the productivity can be increased.