• Journal of Digital Policy
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• v.1 no.2
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• pp.47-52
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• 2022

The absolute dependence on GPS signals for positioning, unstable flight, and short flight time due to battery limitations are the major problems to extend the practical use of drones in the industry. In particular, the short flight time of about 20 minutes is a big issue to the use of drones, and to overcome this, the liquid hydrogen powered drone is being actively developed. However, the revision of the current regulation and certification system for liquid hydrogen powered drone has not been completed yet, making it difficult to test, certify, and commercialize the hydrogen powered drone, which eventually becomes a problem in pre-occupying the increasing drone market. In this paper, we analyze the development trends of hydrogen powered drone and provide the current issues on regulations and certification systems for hydrogen powered drone.

• Journal of Korean Society of Rural Planning
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• v.21 no.3
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• pp.145-154
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• 2015

With the rapid change of rural communities and increasing desire for social welfare, the demand for the quality of public spaces and facilities is increasing. However, inefficient location of rural public space and facility has caused problems such as economic inefficiency, inconvenient accessibility, environmental pollution, unsustainable energy use, and disturbance of visual landscape. This study aims to evaluate suitability of public spaces and facilities in three types of rural village: rural downtown village, rural clustered village, and individual village. As a way to measure the suitability of public spaces and facilities, we assessed indicators of suitability in terms of accessibility, usability, biophysical environment, and sustainable management. To evaluate the accessibility, we applied indicators such as distance from residential areas, public transit, market and public facilities. For the evaluation of biophysical environment, we applied indicators such as slope, elevation, aspect, and occurrence of natural disasters. We analyzed digital maps representing the indicators listed above using GIS. We also conducted a survey and face-to-face interviews to evaluate usability and sustainability of management which are not possible to understand through maps. As a result, we identified that suitability of public spaces and facilities in downtown villages is higher than clustered and individual villages. In particular, suitability of infrastructure facilities, social welfare facilities, and income generation facilities in downtown village are higher than those in clustered and individual villages. The suitability of tourism facilities is generally lower than other types of public facility across the three types of villages. Tourism facilities in clustered village have been identified especially unsuitable compared to other types of villages. We expect the outcome of the research is helpful to improve allocation of public spaces and facilities in rural villages.

• Journal of Korea Foresty Energy
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• v.18 no.1
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• pp.37-45
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• 1999

The greenhouse effect becomes the most serious environmental problem due to excessive emission of carbon dioxide. This effect is aggravated with the deforestation, particularly cleaning of tropical forest for agricultural use. As trees sequester carbon dioxide from atmosphere, forest and forest products play an important role in the use and reduction of carbon dioxide. Wood and wood products require far less energy than the alternatives such as steel, aluminium and concrete for production. Considering high probability of increasing costs in the use of fossil fuel, the relatively low energy requirement for wood processing to very important. Also wood and wood products perform as a long-term storage of carbon. Wood is therefore an environmentally desirable resource. Recently, many alternatives have been introduced for industrial use. In selecting resources, many aspects should be taken into consideration. Wood and wood products have less harmful effects on the environment than the alternatives. We should utilize wood and wood products more efficiently, which should be provided based on the sustainable forest management.

• KIEAE Journal
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• v.11 no.2
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• pp.113-122
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• 2011

About 30% of the total annual energy consumption on the earth is used in the architectural activities, including construction, maintenance management, and demonstration of a building. Also, 40% of the natural resource consumption, 50% of $CO_2$ emissions, and 20%~50% of industrial waste emissions are produced from a building. Unfortunately, the percentage of its energy consumption is staidly increasing year by year, about 8% every year, and it recently causes a sustainable architectural concept to come to the fore globally. Indeed, the importance of the sustainable architecture is increasingly becoming a worldwide trend. BIM(Building Information Modeling) is considered a new paradigm and a powerful method in building design, construction and maintenance. BIM has characteristics similar to a building's systems. All of the components in a model have a parametric relationship to each other. Understanding and capitalizing on these interrelationships typically takes numerous iterations that span multiple projects. Optimizing the integrated strategies and technologies for a high-performance, sustainable design requires a continual look at understanding how they work together to deliver the best potential. Throughout all of these concepts, we are going to be using a variety of tools that revolve around a BIM model. Some of the tools will require a heavier use of BIM than others, but all of them will utilize the model geometry you've created as part of your design. This study presents importance and validity of energy performance analyzation in the pre-design phase for the sustainable architecture with the support of Building Information Modeling (BIM) technology.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.885-891
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• 2017

The energy storage system(ESS) is a core component for exchanging the power system structure of the unidirectional power flow into a bidirectional structure. Its important role has been increasing because it has multiple functions such as output stabilization of new renewable energy, demand management, frequency regulation, etc. However, the performance evaluation technology of ESS in korea is lower than one of advanced countries and the recognition of standardization is also lack compared to advanced countries. Furthermore, in order to more accurately and reliably validate the performance of the ESS in advanced countries, it has been required to perform not only performance testing by H/W devices but also performance verification by S/W tool. Therefore, in order to verify the performance testing of ESS by S/W tool, this paper proposes the modeling method of performance testing devices for MW scaled ESS by using the PSCAD/EMTDC S/W, based on real testing devices in domestic institute. From the simulation results of proposed modeling method, it is confirmed that the proposed modeling method is a useful tool for performance validation of ESS.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.1
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• pp.14-22
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• 2021

Drilling equipment is an essential part used in various fields such as construction, mining, etc., and it has drawn increasing attention in recent years. The drilling method is generally divided into three types. There are a top hammer method that strikes on the ground, a DTH (Down-The-Hole) method that directly strikes a bit in an underground area, and a rotary method that drills by using rotational force. Among them, the DTH method is most commonly used because it enables efficient drilling compared to other drilling methods. In the conventional DTH hammer, the valve between the piston and the bit is opened and closed using a face to face method. In order to improve the power of the DTH hammer, a DTH hammer with foot valve which is capable of instantaneous opening and closing is used in the drilling field. In this study, we designed a lab-scale DTH hammer with the foot valve, and manufactured an evaluation device for the experiment of the DTH hammer. In addition, we analyzed the performance of the DTH hammer adopted with foot valve according to the pressure range of 3-10 bar. As a result, the internal pressure distribution in the DTH hammer was experimentally analyzed, and then, the movement of the piston according to the pressure was predicted. We believe that this study provides the useful results to explain the performance characteristics of the DTH hammer with the foot valve.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.458-468
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• 2021

In this study, we investigated the variations of dissolved organic matter (DOM) in an agricultural reservoir during the monsoon period (June to October, 2020) with respect to the organic carbon concentration (DOC), molecular weight distribution, and optical properties. The monsoon period was divided into three phases - beginning storm (BS), during storm (DS), and after storm (AS). Our results showed significant differences in the concentrations and characteristics of DOM during the summer monsoon. The DOC concentrations were decreased after the monsoon, probably due to a dilution effect. In contrast, increasing trends were observed in the specific UV absorbance (SUVA), and relative abundances of humic-like fluorescence and larger-sized compounds. These observations implied that the large-sized and humic-like organic components with terrestrial origins strongly affected the reservoir DOM after the summer monsoon. Meanwhile, biopolymer size fraction, which is associated with algal activity, became more abundant after the monsoon. These results suggest that DOM with autochthonous sources became dominant as a result of the inflow of nutrients into the reservoir after the storm. Spatial changes in DOM within the reservoir were not pronounced as much as the temporal variations. All taken, it can be concluded that the summer monsoon simply led to the decrease of DOM concentrations while the sources and the quality of DOM underwent substantial changes, which may enrich refractory organic matter in the reservoir. This study reveals the importance of in-depth DOM quality monitoring before and after summer monsoon for effective water quality management in agricultural reservoirs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.29-35
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• 2018

Safety accidents are frequently occurring in day care centers in recent years. The number of types of safety accidents is bumping into, falling, burning, school bus accident, insertion... etc., and the number of children who have died due to such accidents is increasing steadily every year. Therefore, it is urgent to prevent accidents at day care centers. IoT (Internet of Things) is managed by connecting various sensors and related products from the living space to the Internet in order to prevent them from being dangerous. In particular, IoT products can be automatically controlled by smart phones and sensors anytime and anywhere, thus saving energy, time, convenience and prompt accuracy. This paper proposes a research model to prevent and respond to disasters by using SK LoRa communication network and Arduino, which are Internet access networks for building disaster management in schools, kindergartens and day care centers. And various sensors needed for building disaster management express various safety states in the building and suggests a system that can control the residential environment by transmitting and receiving data to smart phone.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.sup1
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• pp.93-101
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• 2008

Management of obesity needs good rapport among pediatrician, parents and children. Through motivational interview, pediatrician should explore practical ways to modify the eating behaviors conducive to obesity. Imbalance between energy intake and consumption contributes to weight gain. Therefore decrease of sedentary behavior (screen time <2 hrs) and increase of physical activity (>60 minutes) is also important in management of obesity. The goal of management is the long-term healthy life though healthy behaviors. Creating a home environment that supports healthy habits and behaviors is an important key to modifying lifestyle behaviors. For example, increasing intake of vegetables and fruits, restriction of sweetened beverage, education of healthy selection of foods, and frequent family dinner may be advisable. Family members should change their own behaviors in order to help their children. Parents should be positive role model and monitor their children authoritatively but not restrictively.

• Korean Journal of Culture and Social Issue
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• v.17 no.4
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• pp.381-393
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• 2011

Eco driving is a strategy to reduce energy consumption and greenhouse gas emissions from motor vehicle. However, it has not received much attention until recently. Psychological studies on this issue have been limited and the majority of existing studies have primarily been based on engineering and educational approaches. This study examined the effects of a self-management technique on two driving behaviors: speeding and putting the gears in neutral while waiting at the signal. The self-management technique consisted of three behavior interventions: goal-setting, self-monitoring, and reward. Three drivers participated in this study. An AB multiple baseline design across participants was adopted. Results showed that the self-management technique was effective in increasing both driving behaviors. Implications of the present findings and suggestions for future research were discussed.