• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.318-325
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• 2019

Recently, research and development on agricultural robots have been on the rise as the interest in smart farming has increased. Robots used in smart greenhouses should be taken into account with the working characteristics and growing environment. This study examined cleaning robots developed through the environmental analysis of smart greenhouses. This study assessed the evaluation method considering the requirements of the pest control robot applicable to the smart greenhouse. The performance and quality assessment criteria were established to conduct tests through the requirements of robots. The required functions and goals of the pest control robot were derived by referring to the robot-related standards. A driving and working ability test was conducted to assess the performance of the robot. The driving test was conducted on the driving performance of the robot and the work capability was tested on the pest control performance. In addition, a durability test was conducted to assess the quality of the robot. The required factors for smart greenhouse robots were derived from the test results. The study results are expected be a standard for an evaluation of a variety of robots for applications to smart greenhouses.

• Ocean policy research
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• v.33 no.2
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• pp.83-119
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• 2018

Under the Korean Marine Environment Management Act (hereunder, the KMEMA), the duty to arrange spill clean-up equipments, including spill clean-up vessels, required by the article 67 of the KMEMA is in essence the provision of public goods since it is a precautionary or preventive measure for the efficient performance of oil spill cleaning up. Also the obligation to control marine pollution and the duty to arrange of anti-pollution measures imposed on polluters is the obligation imposed by the public law in accordance with "the Polluter-Pays Principle". Therefore, the execution of such obligations shall be accompanied by the minimum legal and institutional arrangements. On the other hand, judging whether to form the roles of the public and private sectors in providing public goods is basically a matter of policy decision. However, even if the private sector is allowed to participate in the provision of public goods, it is imperative that a minimum requirement be provided to secure the public interest. Although major countries allows polluters to conclude a preliminary contract with a civil anti-pollution management company, these civilian institutions are in principle constituted by the owners of oil storage facilities. Additionally it is worth noting that it operates as a non-profit organization. In particular, if the practitioner performs pollution control for commercial purposes, their profitability may depend on the size of the pollution, the period spent on pollution control, the size of the equipment and manpower mobilized in the pollution control, and so on. Considering the above problems, caution should be taken to allow marine environmental management companies to be un-limitedly entrusted with the responsibility of arranging measures such as pollution control. In order to allow the marine environmental management contractor to be entrusted for the assignment of duty to protect the marine environment, the marine environment management business should be expanded so that the marine pollutant management capacity satisfies the statutory control capacity. For this purpose, it is necessary to manage and supervise the maintenance and improvement of the control capability of the marine environment management business. It is also necessary to discuss the introduction of the grading system for the control ability of the civil control companies alike in major countries.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.4-25
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• 2010

This study was carried out on scientific conservation treatment based on material characteristics, provenance interpretation, and deterioration diagnosis for seven-storied Jungwon Tappyeongri stone pagoda in Chungju. As a result, main rock of the pagoda is biotite granite with magnetite-series (average $5.86{\times}10^{-3}$ SI unit), containing partly basic xenolith, pegmatite veinlet and feldspar phenocryst. As a result of the provenance presumption of the host rock, a rock around the Songgang stream was identified the same origin. Therefore the rock is appropriate for materials of the pagoda restoration. The deterioration assessment suggested that the pagoda was seriously exfoliated (2.7 to 5.5%), discolored (39.8 to 58.9), and contaminated with repair materials (3.5 to 9.4%), and bioorganisms (19.3 to 24.4%). Accordingly, conservation treatment was carried out based on preliminary investigation for stable conservation of the pagoda. Overall processes were sequentially proceeded by restoration of the replacement stone, cleaning, joining and consolidation. This study sets up an integrated conservation system from preliminary investigation to conservation treatment of the pagoda. Also, the study will contribute for establishing the future-oriented customized conservation treatment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.2
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• pp.71-76
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• 2019

Recently, the demand of labels for product management is increasing, as the automation system becomes more common. the development of functional labels which can be used in various environments has been rapidly proceeded. In the case of a printed circuit board, barcode labels with thermal and chemical stability are generally used due to a high temperature process around $300^{\circ}C$ and chemical cleaning in the manufacturing process. However, the yellowing phenomenon of labels that can lower the resolution of printed barcode image still needs to be prevented. In this study, we prepared a composite coating layer using a silica inorganic binder and a titanium dioxide white pigment, and developed a functional labels with thermal and chemical stability. The silica inorganic binder prepared by sol-gel process was confirmed to show excellent adhesion and abrasion resistance with the polyimide film. The white coating layer could be formed on the polyimide film with mixing the silica inorganic binder and titanium dioxide white pigment. The prepared coating layer showed excellent whiteness and glossiness above $400^{\circ}C$. The excellent chemical stability of the coating layer was also confirmed by the chemical treatment with acidic (pH 1.6) and basic (pH 13.6) cleaners.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.393-402
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• 2020

In the membrane process, it is important to improve water treatment efficiency to ensure water quality and minimize membrane fouling. In this study, a pilot study of membrane process using reservoir water was conducted for a long time to secure high flux operation technology capable of responding to influent turbidity changes. The raw water and DAF(Dissolved Air Flotation) treated water were used for influent water of membrane to analyze the effect of water quality on the TMP (Trans Membrane Pressure) and to optimize the membrane operation. When the membrane flux were operated at 70 LMH and 80 LMH under stable water quality conditions with an inlet turbidity of 10 NTU or less, the TMP increase rates were 0.28 and 0.24 kPa/d, respectively, with minor difference. When the membrane with high flux of 80 LMH was operated for a long time under inlet turbidity of 10 NTU or more, the TMP increase rate showed the maximum of 43.5 kPa/d. However, when the CEB(Chemically Enhanced Backwash) cycle was changed from 7 to 1 day, it was confirmed that the TMP increase rate was stable to 0.23 kPa/d. As a result of applying pre-treatment process(DAF) on unstability water quality conditions, it was confirmed that the TMP rise rates differed by 0.17 and 0.64 kPa/d according to the optimization of the coagulant injection. When combined with coagulation pretreatment, it was thought that the balance with the membrane process was more important than the emphasis on efficiency of the pretreatment process. It was considered that stable TMP can be maintained by optimizing the cleaning conditions when the stable or unstable water quality even in the high flux operation on membrane process.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.380-389
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• 2020

Research on diagnosing and predicting the response of ecosystems caused by environmental changes such as artificial disturbance and climate change is emerging as the most important issue of biodiversity and ecosystem researches. This study aims to clean, standardize, and provide the results of National Ecosystem Survey which should be considered fundamentally in diagnosing and predicting ecosystem changes in the form of dataset. To refine and clean the dataset we developed a simple verification program based on the fifth National Ecosystem Survey Guideline and applied that program to the data from the second (1997~2005), third (2006~2013) and fourth (2014~2018) National Ecosystem Survey. Data quality control processes were implemented including (1) standardization of terminology, (2) similar data table integration, (3) unnecessary attribute and error elimination, (4) unification of different input items, (5) data arrangement in codes, and (6) code mapping for input items. These approaches and methods are the first attempt propose an option for ecological data standardization in Korea. The standardized dataset of National Ecosystem Survey in Korea will be easily accessible, reusable for both researchers and public. In addition, we expect it will contribute to the establishment of diverse environmental policies concerning environmental assessments, habitat conservation, prediction of endangered species distribution and ecological risks due to climate change. The dataset through this study is open freely online via EcoBank (nie-ecobank.kr) which is the first ecological information portal system in Korea developed by National Institute of Ecology.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.16-24
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• 2024

Background: Indoor PM_2.5 concentrations in residential houses can be affected by various factors depending on the season. This is because not only do the climate characteristics depend on the season, but the activity patterns of occupants are also different. Objectives: The purpose of this study is to compare factors affecting indoor PM_2.5 concentrations in apartments and detached houses in Daegu according to seasonal changes. Methods: This study included 20 households in Daegu, South Korea. The study was conducted during the summer (from July 10 to August 10, 2023) and the autumn (from September 11 to October 9, 2023). A sensor-based instrument for PM_2.5 levels was installed in the living room of each residence, and measurements were taken continuously for 24 hours at intervals of one minute during the measurement period. Based on the air quality monitoring system data in Daegu, outdoor PM_2.5 concentrations were estimated using ordinary kriging (OK) in Python. In addition, the indoor activities of the occupants were investigated using a time-activity pattern diary. The affecting factors of indoor PM_2.5 concentration were analyzed using multiple regression analysis. Results: Indoor and outdoor PM_2.5 concentrations of the residences during summer were 15.27±11.09 ㎍/m³ and 11.52±7.56 ㎍/m³, respectively. Indoor and outdoor PM_2.5 concentrations during autumn were 13.82±9.61 ㎍/m³ and 9.57±5.50 ㎍/m³, respectively. The PM_2.5 concentrations were higher in summer compared to autumn both indoors and outdoors. The primary factor affecting indoor PM_2.5 concentration in summer was occupant activity. On the other hand, during the autumn season, the primary affecting factor was outdoor PM_2.5 concentration. Conclusions: Indoor PM_2.5 concentration in residential houses is affected by occupant activity such as the inflow of outdoor PM_2.5 concentration, cooking, and cleaning, as found in previous studies. However, it was revealed that there were differences depending on the season.

• Journal of Agricultural Extension & Community Development
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• v.21 no.1
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• pp.35-82
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• 2014

It was main objectives to find the learners characteristics and educational effects of cyber agricultural technology courses in RDA. For the research, it was followed by literature reviews and internet based survey methods. In internet based survey, two staged stratified sampling method was adopted from cyber training members database in RDA along with some key word as open course or certificate course, and enrollment years. Instrument was composed through literature reviews about cyber education effects and educational effect factors. And learner characteristics items were added in survey documents. It was sent to sampled persons by e-mail and 316 data was returned via google survey systems. Through the data cleaning, 303 data were analysed by chi-square, t-test and F-test. It's significance level was .05. The results of the research were as followed; First, the respondent was composed of mainly man(77.9%), and monthly income group was mainly 2,000,000 or 3,000,000 won(24%), bachelor degree(48%), fifty or forty age group was shared to 75%, and their job was changed after learning(12.2%). So major respondents' job was not changed. Their major was not mainly agriculture. Learners' learning style were composed of two or more types as concrete-sequential, mixing, abstract-random, so e-learning course should be developed for the students' type. Second, it was attended at 3.2 days a week, 53.53 minutes a class, totally 172.63 minutes a week. They were very eager or generally eager to study, and attended two or more subjects. The cyber education motives was for farming knowledge, personal competency development, job performance enlarging. They selected subjects along with their interest. A subject person couldn't choose more subjects for little time, others, non interesting subject, but more subject persons were for job performance benefits and previous subjects effectiveness. Most learner was finished their subject, but a fourth was not finished for busy (26.7%). And their entrying behavior was not enough to learn e-course and computer or internet using ability was middle level as software using. And they thought RDA cyber course was comfort in non time or space limit, knowledge acquisition, and personal competency development. Cyber learning group was composed of open course only (12.5%), certificate only(25.7%), both(36.3%). Third, satisfaction and academic achievement of e-learning learners were good, and educational service offering for doing job in learning application category was good, but effect of cyber education was not good, especially, agricultural income increasing was not good because major learner group was not farmer, so they couldn't apply their knowledge to farming. And content structure and design, content comprehension, content amount were good. The more learning subject group responded to good in effects, and both open course and certificate course group satisfied more than open course only group. Based on the results, recommendation was offered as cyber course specialization before main course in RDA training system, support staff and faculty enlargement, building blended learning system with local RDA office, introducing cyber tutor system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.427-446
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• 2008

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.