• Journal of Internet Computing and Services
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• v.9 no.3
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• pp.129-139
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• 2008

This paper proposes a Ubiquitous Greenhouse Management System (UGMS) based on USN(Ubiquitous Sensor Network) which can be real-time monitoring and controlling of greenhouse's facilities by collecting environment and soil information with environment and soil sensors, and CCTV camera. The existing systems were controlled simply by temperature. Also, it was possible to monitor only at control room in a greenhouse. For solving problems of the exiting system, our system can remotely monitor and control greenhouse by considering environment information. The detail components are as follows. The system includes the sensor manager and the CCTV manager to gather and manage greenhouse information with soil and the environment sensors, and camera. Also the system has the greenhouse database storing greenhouse information and the greenhouse server transmitting greenhouse information to the GUI and controlling greenhouse. Finally, the GUI showing greenhouse condition to users exists in our system. To verify the executability of the UGMS, after developing the greenhouse model, we confirmed that our system could monitor and control the greenhouse condition at remote GUI by applying the UGMS's components to the model.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.6
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• pp.57-65
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• 2003

This study researches attributes , behaviors , satisfaction factors and degrees of curiosity of visitors to recreational forests in the suburbs of a large city. It aims to present suggestions for urban forest development and management policy by offering basic data which help to plan, design and manage recreational forests to increase the quality of these environments. The results are as follows First, in attribute, the visiting rate of males is higher than that of females, and the main users are in their thirties and forties. Sixty percent of visitors graduated from university and their rate of employment is evenly distributed. 95 percent of visitors are residents of the metropolitan area. In terms of behavior, major visitors are family units visiting during summer seasons and for overnight stays. 75% are re-visitors. 85% of visitors came to escape the city with families and friends, keep in good health and experience nature. Second, to extract the factors affecting visitor satisfaction in recreational forests, the natural environment, facilities, and management/use systems were identified as independent variables, while subordinate satisfactions were dependent variables. so regression analysis was used. Thus, the variables affecting the natural environment are quality of water, stream use, biodiversity, fresh air and landscape factors. The variables affecting facilities are puking, convenience, play facilities, sanitary arrangement and camping. Most important among the variables affecting management/use systems are educational facilities and access condition. On the basis of generalizing the study in the existing individual site, we must verify the visiting characteristics in recreational forests in the suburbs of a large city. Since development of recreational forests is understood as a sequence considering a site and a given condition, and since management and improvement must unfold according to these characteristics, a strategy is needed to reveal visitors' opinions about the site. Depending on the facilities and service, satisfaction of recreational forests is generally influenced by social and economic qualities. Also, this study can look into the effect according to use pattern motive and season. As suburban recreational forests have many overnight-users and younger men, programs suitable for these groups are needed. On the basis of variables affecting satisfaction according to natural environment, facilities, and use system, policies which can manage the natural environment and introduce educational programs are needed.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.785-791
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• 2009

Using artificial rainfall simulator, the soil loss, which is deemed as the most cause of muddy water problem among Non-point source (NPS) pollutant, was studied by the analysis of direct runoff, groundwater discharge, and soil water storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared soil as slope increases from 5% to 20%. The direct runoff volume from straw covered surface were much lower than bared surface. The infiltration capacity of straw covered surface increased, because the surface sealing by fine material of soil surface didn't occur due to the straw covering. Under the same rainfall intensity and slope condition, 2.4~8.2 times of sediment yield were occurred from bared surface more than straw covered surface. The volume of infiltration increased due to straw cover and the direct runoff flow decreased with decrease of tractive force in surface. To understand the relationship of the rate of direct runoff, groundwater discharge, and soil water storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, except between the rate of groundwater storage and rainfall intensity.

• Research in Plant Disease
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• v.24 no.1
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• pp.52-58
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• 2018

Pear scab and rust are the major diseases causing severe epidemics in organic cultivation of pear trees. Incidences of pear scab and rust were compared in organically managed plots and conventionally managed plots to obtain optimum application schedule of environment-friendly control agents in organically managed plots. Organically cultural practice with 10 time-applications of lime sulfur and Bordeaux mixture showed higher than 40% of control efficacies of pear scab and rust compared to conventionally cultural practice. Organically cultural practice with 8 time-applications of lime sulfur considering weather condition showed higher than 30% of control efficacies of pear scab compared to conventionally cultural practice. The results suggest that proper application of environment-friendly control agents such as lime sulfur considering weather condition will enable effective control of the major diseases for organic cultivation of pear.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.124-131
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• 2000

In this study, the NEURAL NETWORK (hereinafter referred to as NN) was applied to control of the nonlinear factors for turning movement of the crawler vehicle and experiment was carried out using a small model of crawler vehicle in order to inspect an application of NN. Furthermore, CHAOS NEURAL NETWORK (hereinafter referred to as CNN) was also applied to this control so as to compare with conventional NN. CNN is especially effective for plane in many variables with local minimum which conventional NN is apt to fall into, and it is relatively useful to nonlinear factors. Experiment of turning on the slope of crawler vehicle was performed in order to estimate an adaptability of nonlinear problems by NN and CNN. The inclination angles of the road surface which the vehicles travel on, were respectively 4deg, 8deg, 12deg. These field conditions were selected by the object for changing nonlinear magnitude in turning phenomenon of vehicle. Learning of NN and CNN was carried out by referring to positioning data obtained from measurement at every 15deg in turning. After learning, the sampling data at every 15deg were interpolated based on the constructed learning system of NN and CNN. Learning and simulation programs of NN and CNN were made by C language ("Association of research for algorithm of calculating machine (1992)"). As a result, conventional NN and CNN were available for interpolation of sampling data. Moreover, when nonlinear intensity is not so large under the field condition of small slope, interpolation performance of CNN was a little not so better than NN. However, when nonlinear intensity is large under the field condition of large slope, interpolation performance of CNN was relatively better than NN.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.261-270
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• 2002

The artificial aeration in the middle and the small scale reservoirs is widely used to destroy the stratified layer and algal boom. This study has been conducted at the Youncho reservoir located in Keoje island since Jan. 2000 to suggest the most suitable control strategy of the artificial aeration and reduce the side effect. The main results obtained from this research are as follows. The starting time of aeration for destratification was adjusted from the end of March to the beginning of April when the natural stratification is started. In order to prevent an anoxic condition the artificial mixing should be started by the middle of April when the DO in hypolimnion is dropped to less than $5mg/{\ell}$. The decrease DO, caused by the increase in water temperature, spreads rapidly from hypolimnion to themocline. Thermal stratification disappeared after the onset of artificial aeration within 7 days in the Yuncho reservoir. The air diffusers decrease water temperature in the layer of epilimnion and thermocline, but rise it in hypolimnion. The continuous operation of air diffuser prevent the stratification and anoxic condition in hypolimnion despite of the rising of water temperature and algal abundance. The algal abundance is not observed in effective zone by aeration. The turbidity rising problem induced from the aeration is avoided by keeping an air diffuser about 1.5m high from the bottom of lake. During the summer season, ceasing the aeration should be decided carefully. And also, it is necessary to operate the system it considering weather and temperature, and depending on the number and the position of aerators.

• Physical Therapy Korea
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• v.14 no.2
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• pp.21-28
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• 2007

The purpose of this study was to compare the onset times of muscle activities and the order of muscle firing in erector spinae, multifidus, rectus abdominis and biceps brachii during perturbation between subjects with and without work-related chronic low back pain (LBP). Twenty-nine subjects, 14 with and 15 without LBP, participated in this study. The muscle responses were measured by surface EMG (electromyography) during perturbation in eye opened and eye closed conditions. The EMG onset times of the erector spinae, multifidus, rectus abdominis and biceps brachii were similar between groups in eye closed condition. But the onset times of the erector spinae, multifidus, rectus abdominis were significantly delayed in subjects with LBP in eye opened condition. The results provide an evidence for impaired feed-forward control of the trunk muscles in subjects with LBP. Further studies are needed to identify whether the impaired feed-forward control of the trunk muscles is the contributing factor to LBP.

• Journal of the Korean Solar Energy Society
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• v.40 no.2
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• pp.25-36
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• 2020

The Korean government has a plan to mandate zero-energy buildings in 2020 for public and 2025 for private buildings. In order to design a zero-energy building, insulation and airtightness, which are the most basic elements of passive house technology, are required, and the government has been accomplished this through step-by-step strengthening of related standards. In passive house with high thermal insulation and airtightness performance, the heat introduced into the building through solar radiation can be stored for a long time to keep the inside warm during winter. On the other hand, during summer, heat introduced into the building cannot be easily released to outside, so it is necessary to actively block solar radiation and high temperature outdoor air to prevent an increase of indoor temperature. Therefore, this study aims to derive an appropriate operation condition of passive house to maintain the indoor temperature at an suitable level according to the ventilation methods and solar shading conditions. As a result, under the conditions that the outdoor temperature was 28℃ or less, the ventilation using a heat recovery ventilation system at daytime and natural ventilation at nighttime were selected for the most appropriate operation method. In addition, in the case of solar shading, it was found that blocking solar radiation at daytime using the blind and open the blind at nighttime to ensure natural ventilation were selected for the most appropriate solar shading condition.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.654-658
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• 2012

In this work, the properties of an organic-inorganic hybrid insulating material using an inorganic filler and polyurethane foam with different foaming conditions were investigated. At weight ratios of polyol and isocyanate of 1 to 1.2 good foaming properties were noted. In addition, an addition of 0.4 g of water, 0.1 g of surfactant, and 0.1 g of catalyst with respect to the composites of polyol at 5 g and isocyanate at 6 g showed the lowest apparent density and thermal conductivity. The pore size was smaller in the organic-inorganic hybrid foaming body with an increase in the $CaCO_3$ addition amount. Moreover, the apparent density and thermal conductivity were increased when the added amount of $CaCO_3$ increased. Increasing the amount of $CaCO_3$ powder is expected to improve the flame retardant capabilities; however, doing this tends to increase the apparent density and thermal conductivity.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.101-111
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• 2008

As the quality of life improves, people want to live in more pleasant environment with beautiful trees, clean air and water. They are keenly interested in environmental issues as well as living environment of apartment which is a trademark of modern life. With this situation, the function and roles of landscaping trees have been recognized as a critical factor to improve living environment. As people have asked for more demands on those trees, it has raised more issues on the defect of trees and is required the solution to those issues. So, the purpose of this study was to survey the reasons of defects and find out those solutions. The data on defects in 1990s was referenced to the reports issued by SH Corporation in 1994 and 1997. The data on defects in 2000s are collected from March, 2006 to May 2006 based on the survey for apartments already constructed by Korea Housing Corporation. The results of the survey were shown that, in the year of 1994, landscaping trees causing high rate of defects were Acer buergerianum (92%), Pinus densiflora(85.7%), Celtis sinensis(80%), Cydonia sinensis(75%) and Diospyros kaki(66.6%), and in the year of 1997, landscaping trees causing high rate of defect were Ziziphus jujuba(100%), Cornus alba(65.2%), Diospyros kaki(60%), Thuja occidentalis(60%), and Metasequoia glyptostroboides(42%). And, in the year of 2006, landscaping trees causing high rate of defect were Sophora japonica(100%), Taxus cuspidata(80%), Magnoila quinquepeta (75%), Acer palmatum(62.5%) and Ginkgo biloba(50%). Because the reasons of defects were various according to the conditions including the climate, location, time and landscaping trees carried into the work area, we present the problems and solutions to those defects. Since the landscaping trees are living creatures, the factors of defects were various and complicated according to the site condition. So, in the period of warranty, contractor should designate the tree manger who can recognize the situation and take suitable action within timely manner.