• Korean Journal of Medicinal Crop Science
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• v.26 no.6
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• pp.477-481
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• 2018

Background: Recently, jujube (Zizyphus jujuba Mill.) has been attracting attention as a fruit, and its cultivation in rain shelter house is increasing to produce the high quality fresh jujube. This study was carried out to investigate the growth and fruit characteristics of jujube according to the types of rain shelter house. Methods and Results: The characteristics of 5-year-old Bokjo cultivar cultivated in 3 types of rain shelter house, multi span rain shelter house with roof vent (Type I), single span house with a column in the center and roof vent (Type II) and single span house with a column in the center and without roof vent (Type III), and open field were examined. The sprouting and blooming period were different among the types of rain shelter house. The diameter of main stem was higher in rain shelter houses than in the open field. There was no a significant difference in fruit number per leaf stem among the types of cultivation. The incidence of fruit cracking in open field cultivation which was 51.2% was much higher than that in Type I 21.6%, Type II 19.3%, and Type III 25.5%. The fruit size and weight in rain shelter houses, especially in Type III rain shelter house were higher than those in the open field and the soluble solids content of fruit in Type I and Type II was higher than in Type III rain shelter house and the open field. Conclusions: The results show that the growth and fruit quality of jujube were improved by cultivation in rain shelter house, and affected by the types of rain shelter house.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.221-227
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• 2005

Aim of this study is to investigate an aerodynamic effect of a drag-reducing device on a heavy-duty truck. The vehicle experiences two different kinds of aerodynamic forces such as drag and uplifting force (or downward force) as it is traveling straight forward at constant speed. The drag force on a vehicle may cause an increase of the rate of fuel consumption and driving instability. The rolling resistance of the vehicle may be increased as result of the negative uplifting or downward force on the vehicle. A device named roof-fairing system has been applied to examine the reduction of aerodynamic drag force on a heavy-duty truck. As for a engineering design information, the drag-reducing system should be studied theoretically and experimentally for the best efficiency of the device. Four different types of roof-fairing model were considered in this study to investigate the aerodynamic effect on a model truck. The drag and downward force generated by vehicle has been obtained from numerical calculation conducted in this study. The forces produced on four fairing models considered in this study has been compared each other to evaluate the best fairing model in terms of aerodynamic performance. The result shows that the roof-fairing mounted truck has bigger negative uplifting or downward force than that of non-mounted truck in all speed ranges, and drag force on roof-fairing mounted truck has smaller than that of non-mounted truck. The drag coefficient $(C_D)$ of the roof-fairing mounted truck (Model-3) is reduced up to $41.3\%$ than that of non-mounted trucks (Model-1). A downward force generated by a roof-fairing mounted on a truck is linearly proportional to the rolling resistance force. Therefore, the negative lifting force on a heavy-duty truck is another important factor in aerodynamic design parameter and should be considered in the design of a drag-reducing device of a tractor-trailer. According to the numerical result obtained from present study, the drag force produced by the model-3 has the smallest of all in all speed ranges and has reasonable downward force. The smaller drag force on model-3 with 2/3h in height may results of smallest thickness of boundary layer generated on the topside of the container and the lowest intensity of turbulent kinetic energy occurs at the rear side of the container.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.455-468
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• 2013

In recent, various types of steel pipe-roof methods, which is reinforced by mortar after propulsion of steel pipe into the ground, have been used for the construction of trenchless underpass. Integrated steel pipe-roof has flexural stiffness and can resist against overburden load and reduce the stress acting on the concrete underpass structures. Due to arching effect, vertical and horizontal stress distribution around the steel pipe-roof is changing. In this study, therefore, the characteristic of stress distribution around the underpass induced by the construction of integrated steel pipe-roof is investigated by using numerical method. To examine the soil-structure interaction, interface element is introduced. Results show that vertical stress acting on the concrete structure placing inside the steel pipe-roof is significantly reduced due to arching effect and flexural stiffness of integrated steel pipe-roof. Design load can be reduced and effective design of underpass will be available if the earth pressure reduction due to arching effect is considered in the design stage.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.1057-1065
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• 2010

Recent urban concerns over environmental problems have furthered interest in green roof system. Plant growth and load bearing capacity of an underlying roof are key factors to determine an optimal system. This study was carried out to develop an optimal extensive green roof system for shrubs assessing the effects of substrate type and soil depth on the growth of $Rhododendron$ $indicum$ Sweet. in the experimental systems with different soil types and depths from 2001 to 2008. Substrate types of perlite alone and blended with sandy loam (v/v, 1:1) were used on the experimental systems with depths of 30 cm, 45 cm, and 60 cm. The survival rate of the plants on the perlite alone + 45 cm soil depth system (RS-A-45) was 100% during the experimental period, while those on the perlite alone + 30 cm soil depth system (RS-A-30) and perlite blended + 60 cm soil depth system (RS-B-60) showed 33% and 67%, respectively, in 2008. The overall plant growth and soil properties of RS-A-45 were superior to the others. At 8 years after installation, the total weight of RS-A-45 including plant fresh weight was about $376.6kg{\cdot}m^{-2}$ in field capacity indicating RS-A-45 can be optimal extensive and light weight green roof system.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.89-97
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• 2012

Green roofs are being created in various purposes to use spaces. Most of them have been built with a goal as a resting place. However, the use of the green roofs needs to be raised. Otherwise, maintenance and administration of green roofs can be loosened. In addition, budget or cost involved can be wasteful. Therefore, this study makes a proposition if the satisfaction of green roofs is higher, the use of green roofs could be increased more. We are willing to analyze how beneficial the awareness can affect for the satisfaction with regard to green roofs. The findings can be helpful to provide a foundation data for raising the use of green roofs. We believe that the awareness benefits and satisfaction could be different depending on the facility's status on green roofs. Therefore, we classified green roofs of 11 department stores, in Seoul, into four types. Among them, we paid attention to five department stores that were able to represent each type. We analyzed the awareness benefits and satisfaction depending on the type of green roofs. We analyzed casual relationships between them using Structural Equation Modeling. We expect that the landscape architecture scholars will expand research on the various determinants in using green roof. een Roof; Type of Green Roof; Benefit Awareness; Satisfaction; Structural Equation Modeling;

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.10a
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• pp.197-200
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• 2010

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.161-169
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• 2018

Korea's traditional hanok houses are roughly divided into tiled-roofed, thatched-roofed, shingle-roofed, and oak bark-roofed houses according to their materials. In thatched-roof houses, there are various styles according to regional characteristics regarding building materials, slope, shape, and tying method. Unfortunately, as the number of thatched-roof houses have been rapidly decreasing since industrialization, it is difficult to find these characteristics of traditional houses. The study revealed that there was a roofing material a higher percentage of houses with thatched roofs than houses with tiled roofs. Furthermore, the plane occupies a large number of left and right protruding types and layered types, and there is no partition wall between Jeongji and maru. In addition, the opening in the front has characteristics of the Northern region that is responsible for lighting and ventilation, not for access. In the case of thatched-roof houses in Goseong Wanggok Village, the field survey suggests that a high percentage of buildings can recover their original characteristics.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.49-54
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• 2008

This study is to investigate an optimal size and position of PV system for apartment complex enough the electrical load matching analysis. The 4 types of arrangements of apartment buildings are considered as follows; ㅡtype, alternative ㅡtype, ㄱtype and ㅁtype. We assume that the studied site is composed of 9 buildings. Firstly, solar access evaluation of roof and facade in apartment buildings was performing with the hourly simulations of total received insolation on each surface considering the hading effect of buildings. Electrical load profile of typical Korean apartments was investigated for the lad matching analysis. To calculate an annual total PV output, we used MERIT program which is a sourly based load matching tool developed by ESRU. TRY weather data of Daejeon are applied for this analysis. Result shows that approximately 11% of total electric load of the site can be supplied by the PV system in the case of full installation of PV system at the whole south-face roof area of 9 buildings in this stuided apartment complex. Depending of a various installation option of roof and facade area, the possible ratio of PV supply in total electrical load varies from 9% to 42%. Among the 4 arrangement types, the ㅡ type revealed the best option for the maximum output of PV system.

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.60-66
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• 2008

This study is to investigate an optimal size and position of PV system for apartment complex through the electrical load matching analysis. The 4 types of arrangements of apartment buildings are considered as follows; ㅡtype, alternative ㅡtype, ㄱtype and ㅁtype. We assume that the studied site is composed of 9 buildings. Firstly, solar access evaluation of roof and facade in apartment buildings was performed with the hourly simulations of total received insolation on each surface considering the shading effect of buildings. Electrical load profile of typical Korean apartments were investigated for the load matching analysis. To calculate an annual total PV output, we used MERIT program which is a hourly based load matching tool developed by ESRD. TRY weather data of Daejeon are applied for this analysis. Result shows that approximately 11% of total electric load of the site can be supplied by the PV system in the case of full installation of PV system at the whole south-face roof area of 9 buildings in this stuided apartment complex. Depending on a various installation option of roof and facade area, the possible ratio of PV supply in total electrical load varies from 9% to 42%. Among the 4 arrangement types, the ㅡtype revealed the best option for the maximum output of PV system.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.137-142
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• 2018

The aim of this paper was to analyze the determinants of farm household income in the Gyeongbuk province. Data from 5,254 villages in the Gyeongbuk province were used. The main results are as follows. First, the percentage of self-supporting villages for fishing villages was 10.8%, which was higher than the average of 6.4%; however, the percentage of self-supporting villages for mountain villages was only 2.7 percent. Second, the level of income was estimated to positively correlate with the ratio of the roof improvement rate, a sisterhood relationship, farming households, and the number of people under the age of 14. Finally, the results show that variables such as age, farming percentage, roof improvement ratio, and a sisterhood relationship were significant. When the percentage for the roof improvement ratio was higher, the ratio for a sisterhood relationship with another city was higher, and when the proportion of farmers was higher, the average income of the village was higher. Based on the results from the above analysis, the following policy implications are suggested. First, the income levels of rural villages in the 1970s are related to the Saemaul project in Korea. In other words, the Saemaul project contributed to improving the farming household income by direct and indirect methods. Second, it can be seen that it is important to develop policies that take into account different village types within rural areas.