• The Mathematical Education
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• v.49 no.3
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• pp.375-387
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• 2010

The focus of this article is the strategies young children use to solve rectangular covering tasks before they have been taught area measurement. seventy nine children from Grade 1 to 4 were observed while they solved various array-based tasks, and their drawing and explanation were collected and analyzed. Children's solution strategies were classified into incomplete covering, inadequate array, array constructed from moveable unit, measurement of one dimension, measurement of two dimension, and calculation. Implications for the learning of area measurement are addressed.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.116-119
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• 2005

As to the synthetical estimation of land covering parameters or the compounded land covering classification for multi-resolution satellite data, former researches mainly adopted linear or nonlinear regression models to describe the regression relationship of land covering parameters caused by the degradation of spatial resolution, in order to improve the retrieval accuracy of global land covering parameters based on 1;he lower resolution satellite data. However, these methods can't authentically represent the complementary characteristics of spatial resolutions among different satellite data at arithmetic level. To resolve the problem above, a new compounded land covering classification method at arithmetic level for multi-resolution satellite data is proposed in this .paper. Firstly, on the basis of unsupervised clustering analysis of the higher resolution satellite data, the likelihood distribution scatterplot of each cover type is obtained according to multiple-to-single spatial correspondence between the higher and lower resolution satellite data in some local test regions, then Parzen window approach is adopted to derive the real likelihood functions from the scatterplots, and finally the likelihood functions are extended from the local test regions to the full covering area of the lower resolution satellite data and the global covering area of the lower resolution satellite is classified under the maximum likelihood rule. Some experimental results indicate that this proposed compounded method can improve the classification accuracy of large-scale lower resolution satellite data with the support of some local-area higher resolution satellite data.

• Korean Journal of Child Studies
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• v.25 no.1
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• pp.13-29
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• 2004

In this study of strategies used by young children in solving rectangular covering tasks before they have been taught area measurement, 75 5-, 6-, and 7-year-old children were asked to solve 3 rectangular covering tasks with a moveable unit. Three different sized units (4 cm., 2 cm., and 1 cm. cardboard squares) were provided and the children were asked to work out how many would be needed to cover a drawn rectangle. The resulting 5 developmental levels include incomplete covering, incomplete arrangement, complete covering, estimating, and measuring. Children using more advanced strategies were able to find correct number of units. While the tendency among older children was to use more advanced strategies, even 5-year-olds had an intuitive understanding of rectangular area measurement.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.7-16
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• 1991

This research investigated soil, plants, insects and birds in the Mongchon Earth Fort, establishing the 11 plots, according to planting treatment, in order to present management method for ecological stability of species in the ground covering plots. The results of analysizing the investigated data summarize as follows. 1. In the ground covering plots without upper layer, the density and coverage of middle and low layer in the natural plots were higher than those in the artificial plots. 2. In the ground covering plots without upper layer, the density and coverage of low layer were higher than those in the artificial, while the density and coverage of herb layer in the natural plots were lower. 3. Whether there was upper layer or not, the total species diversity and enenness of the ground covering community in the natural plot without artificial treatment and natural treatment plot were higher than those ground covering. 4. In the ground covering plots with upper layer, the species diversity of ground covering in the plots without artificial treatment is high, while the species diversity in the plots with natural treatment caused the secondary succession is higher than that of the natural plot. 5. In the ground covering plots without upper layer, the species diversity in the plots with artificial management was higher than that of natural plots, while the evenness in the plots with artificial management was lower. 6. In the ground covering plots with upper layer the species diversity of insect in the plot of natural state was higher than that of insect in the plots with artifical treatment. 7. Synthetically, in the area with upper layer the species diversity of the ground covering community in the natural plot was high, while in the area without upper layer, the species diversity of it in the plots with artificial treatment was high. The insect turned up frequently in the plots of high species diversity of the ground covering, so the bird did in the plots of high species diversity of the ground covering and insects.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.251-259
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• 2013

Among various Green Infrastructure measures for urban stormwater management, effects of porous pavement were quantitatively examined in terms of hydrological cycle. Different scenarios for porous pavement were introduced on a SWMM model and the effects were compared and analysed using discharge hydrographs. Two types of pavements having different runoff coefficients (0.05 & 0.5) were introduced to cover different ratio of entire road areas (100 %, 77.5 % and 40.4 %) and these made up in total 6 different scenarios. Total runoff volume was reduced and peak flow was significantly decreased by applying the porous pavement. The highest reduction for total runoff was shown from S-6(covering area: 100 %, runoff coefficient: 0.05) as 19 % followed by S-5(covering area: 77.5 %, runoff coefficient: 0.05, 16 %), while that of S-2(covering area: 40.4 %, runoff coefficient: 0.05) and S-1(covering area: 40.4 %, runoff coefficient: 0.5) were the lowest with 8 % and 5 %. This proved that the application of porous pavement would improve urban hydrological cycle.

• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.215-223
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• 2010

In order to develop an precision aerial pesticide application system to be attached to an unmanned helicopter which can be applied to small lots of land, this study analyzed the flowing and spraying characteristics of the spray droplets by the main rotor downwash by setting the application conditions at the flight altitude of 3 m, the diameter of main rotor of 3.1 m, the boom length of around 2.8 m, and the spraying rate of 8 L/ha. The results of this study are summarized below. Through analysis of the covering area ratio of the spray droplets by main rotor downwash by nozzle type, boom with tilt angle and height, it was found that the covering area ratio of the twin flat-fan nozzle of around 25% was more uniform than other types of nozzle, also boom with $10^{\circ}$ tilt angle and spraying height of 3 m was shown to be the appropriate conditions for aerial application of pesticides. It was found that the nozzle position to minimize the scattering loss of spray droplets due to vortex phenomenon at both ends of the main rotor was around 10 cm from the end of the main rotor. An application test for the aerial pesticide application system attached to the HUA-ACEI unmanned helicopter developed by the Rural Development Administration showed that the range of covering area ratio of the spray droplets was 10-25%, and the spraying width was approximately 7 m when over 10% of covering area ratio was considered for valid spraying.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.3
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• pp.452-466
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• 1996

The purpose of this study is to proviede basic data for designing sports-brassiere by a questionnaire survey about sports-brassieres preferences and physiological wearing test. The results of the survey and the physiological wearing tests on sports-brassieres are as follow; 1. According to the survey, dissatisfied factors on the sports-brassiere are "drooping and vibrating of the breasts". Preferable factors are supporting breasts by stretch and seldom changing its position by motion. The bigger cup-size and more hemispherical-type causes more discontent than flat-type. 2. The shape of breasts is oval, on what ground, horizontal line is longer than vertical. For the cross section of bust line, shirts type.brassiere is more gently curved than cup-brassiere. 3. The feeling of wearing comfort is correlated with bust.up, shield, close adhesion. The vibration of breasts is correlated with covering urea and close adhesion, and the changing band's position by movement, close adhesion. Too much covering area or strain are in inverse correlation of the comfort. 4. The rate of prevention of vibration is 75~80% on superior sports-brassieres, which has broad covering area and excellent close adhesion. adhesion.

• Research in Plant Disease
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• v.11 no.2
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• pp.198-200
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• 2005

An epidemic of the white dusty covering of grape clusters and canes by dust-like particles occurred in many vineyards near Gimcheon, Gyeongbuk area since 2000. Although the covering was severe, it seldom resulted in appreciable damage to vine health except drastical reduction of grape quality. It appears that the abnormal growth of a resident yeast Hanseniaspora (Kloeckera) sp. is related to the white dusty covering on the grape surface.

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.88-92
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• 2002

The study was conducted to estimate stimulation of plant growth of blue and red leaf lettuce (Lactuca sativa L.) as affected by covering methods with vinyl materials containing concentrated PO film. Plants were grown in direct, direct and tunnel, and tunnel covering with 'Pasraido materials' from October 13 to 31. With the covering mean air temperature, soil temperature, leaf temperature and relative humidity remarkedly increased. Higher temperature was observed in the order of direct and tunnel, direct, tunnel covering and the control. Photosynthetic photon flux (PPF, $\mu$mol m$^{-2}$ . s$^{-1}$ ) was observed in reverse order of temperature. Concentration of $CO_2$ was higher during night than during day under the light. Accumulation of highest $CO_2$ at night was obtained from direct coverings followed by direct and tunnel, tunnel covering and the control. Plant height, leaf number and leaf area of blue and red lettuces were stimulated by direct covering. However, there was no significant difference.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.137-147
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• 1999

This paper studies on the optimal bus network design in the framework of the set covering theory. The theory enables to cover passenger's loading and alighting areas as the set, and maximize the covering set as much as possible. In other words, it calculates the minimal set of the bus routes for covering whole bus passengers demand. After the optimal set of the bus routes is generated by the set covering theory, multimodal traffic equilibrium assignment is used for evaluating the generated set in terms of passenger's mode and route choice behavior. Whilst most previous works on it have been based on analyzing a specific route in a limited area, this study seeks to optimize the whole bus network.