• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.54-60
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• 2009

The purpose of this study is to analyze the impacts of three-dimensional land cover on changing urban air temperatures and to explore some strategies of urban landscaping towards mitigation of heat build-up. This study located study spaces within a diameter of 300m around 24 Automatic Weather Stations(AWS) in Seoul, and collected data of diverse variables which could affect summer energy budgets and air temperatures. The study also selected reflecting study objectives 6 smaller-scale spaces with a diameter of 30m in Chuncheon, and measured summer air temperatures and three-dimensional land cover to compare their relationships with results from Seoul's AWS. Linear regression models derived from data of Seoul's AWS revealed that vegetation volume, greenspace area, building volume, building area, population density, and pavement area contributed to a statistically significant change in summer air temperatures. Of these variables, vegetation and building volume indicated the highest accountability for total variability of changes in the air temperatures. Multiple regression models derived from combinations of the significant variables also showed that both vegetation and building volume generated a model with the best fitness. Based on this multiple regression model, a 10% increase of vegetation volume decreased the air temperatures by approximately 0.14%, while a 10% increase of building volume raised them by 0.26%. Relationships between Chuncheon's summer air temperatures and land cover distribution for the smaller-scale spaces also disclosed that the air temperatures were negatively correlated to vegetation volume and greenspace area, while they were positively correlated to hardscape area. Similarly to the case of Seoul's AWS, the air temperatures for the smaller-scale spaces decreased by 0.32% ($0.08^{\circ}C$) as vegetation volume increased by 10%, based on the most appropriate linear model. Thus, urban landscaping for the reduction of summer air temperatures requires strategies to improve vegetation volume and simultaneously to decrease building volume. For Seoul's AWS, the impact of building volume on changing the air temperatures was about 2 times greater than that of vegetation volume. Wall and rooftop greening for shading and evapotranspiration is suggested to control atmospheric heating by three-dimensional building surfaces, enlarging vegetation volume through multilayered plantings on soil surfaces.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1102-1139
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• 2002

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2000 and 2001 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD technologies were widely applied for developing facilities and their systems. (2) Most of papers related with heat transfer analysis and heat exchanger shows dealt with convection, evaporation, and channel flow for the design application of heat exchanger. The numerical heat transfer simulation studies have been peformed and reported to show heat transfer characteristics. Experimental as well as numerical studies on heat exchanger were reported, while not many papers are available for the system analysis including heat exchanger. (3) A review of the recent studies on heat pump system shows that performance analysis and control of heat pump have been peformed by various simulations and experiments. The research papers on multi-type heat pump system increased significantly. The studies on heat pipe have been examined experimently for change of working characteristics and strut lure. Research on the phase change has been carried out steadily and operation strategies of encapsulated ice storage tank are reported experimentally in several papers. (4) A review of recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. Evaporation and condensation heat transfer characteristics are investigated for tube shapes and new alternative refrigerants. Studies on components of refrigeration/air conditioning system are carried to examine efficiency for various compressors and performance of new expansion devices. In addition to thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out, however research works on two-phase flow seemed to be insufficient. (5) A review of the recent studies on absorption cooling system indicates that heat and mass transfer phenomena have been investigated to improve absorber performance. Various experimental data have been presented and several simulation models have been proposed. A review of the recent studies on duct and ventilation shows that ventilation indices have been proposed to quantify the ventilation performance in buildings and tunnels. Main efforts have been focused on the applications of ventilation effectiveness in practice, either numerically using computational fluid dynamics or experimentally using tracer gas techniques. (6) Based on a review of recent studies on indoor thermal environment and building service systems, research issues have mainly focused on many innovative ideas such as underfloor air-conditioning system, personal environmental modules, radiant floor cooling and etc. Also, the new approaches for minimizing energy consumption as well as improving indoor environmental conditions through predictive control of HVAC systems, various activities of building energy management and cost-benefit analysis for economic evaluation were highlighted.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.48-56
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• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.73-85
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• 2009

An investigation was conducted to get the basic data for establishing structural safety and environmental management of tomato greenhouses in Chungnam region. The contents of the investigation consisted of actual state of greenhouse structures and environmental control facilities. Most of greenhouses were arch type single-span plastic houses and they had too low height for growing tomatoes. Frameworks of multi-span greenhouses were suitable, but those of single-span were mostly insufficient. Every greenhouse had thermal curtain movable or covering fixed inside the greenhouse for energy saving, and heating facilities were mostly warm air heater. Irrigation facilities were mostly drip tube and controlled by manual operation or timer. Almost all of the greenhouses didn't install high level of environmental control facilities such as ventilator, air circulation fan, $CO_2$ fertilizer, insect screen, supplemental light, and cooling device.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.79-96
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• 2021

Green infrastructure planning represents landscape planning measures to reduce particulate matter. This study aimed to derive factors that may be used in planning green infrastructure for particulate matter reduction using text mining techniques. A range of analyses were carried out by focusing on keywords such as 'particulate matter reduction plan' and 'green infrastructure planning elements'. The analyses included Term Frequency-Inverse Document Frequency (TF-IDF) analysis, centrality analysis, related word analysis, and topic modeling analysis. These analyses were carried out via text mining by collecting information on previous related research, policy reports, and laws. Initially, TF-IDF analysis results were used to classify major keywords relating to particulate matter and green infrastructure into three groups: (1) environmental issues (e.g., particulate matter, environment, carbon, and atmosphere), target spaces (e.g., urban, park, and local green space), and application methods (e.g., analysis, planning, evaluation, development, ecological aspect, policy management, technology, and resilience). Second, the centrality analysis results were found to be similar to those of TF-IDF; it was confirmed that the central connectors to the major keywords were 'Green New Deal' and 'Vacant land'. The results from the analysis of related words verified that planning green infrastructure for particulate matter reduction required planning forests and ventilation corridors. Additionally, moisture must be considered for microclimate control. It was also confirmed that utilizing vacant space, establishing mixed forests, introducing particulate matter reduction technology, and understanding the system may be important for the effective planning of green infrastructure. Topic analysis was used to classify the planning elements of green infrastructure based on ecological, technological, and social functions. The planning elements of ecological function were classified into morphological (e.g., urban forest, green space, wall greening) and functional aspects (e.g., climate control, carbon storage and absorption, provision of habitats, and biodiversity for wildlife). The planning elements of technical function were classified into various themes, including the disaster prevention functions of green infrastructure, buffer effects, stormwater management, water purification, and energy reduction. The planning elements of the social function were classified into themes such as community function, improving the health of users, and scenery improvement. These results suggest that green infrastructure planning for particulate matter reduction requires approaches related to key concepts, such as resilience and sustainability. In particular, there is a need to apply green infrastructure planning elements in order to reduce exposure to particulate matter.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.2
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• pp.352-362
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• 2015

The purpose of this study was to examine portion sizes and nutritional quality of foods served to children at Community Child Centers (CCCs), July 2014, in Korea. A survey was administered to foodservice employees working at CCCs. Thirty-nine participants completed the self-administered questionnaire regarding CCCs foodservice practices. In the weight test, fifteen volunteers of demonstrated typical portion sizes for $5^{th}$ grade elementary school students. Nutrition knowledge scores were significantly different between foodservice employees with experience taking a foodservice class for one year (6.04 out of 10.0 points) and those without experience (4.58 points). Foodservice employees with experience taking a foodservice class scored significantly higher in performing meal serving practices, e.g., wearing a sanitary cap and apron when serving food, than those without experience. The amount of foods served for children did not meet standard serving sizes; portion sizes of rice, soup, main dish, side dish and kimchi served by foodservice employees were 87.3%, 63.2%, 56.5%, 37.1% and 81.3% of standard serving sizes, respectively. When energy and nutrient intakes from portion sizes were calculated, energy, vitamin A, thiamin, riboflavin and calcium intakes did not meet standards for nutrition control of school meals. However, protein, vitamin C and iron intakes met more than 100.0% of standards. These findings suggest that foodservice employees with experience taking a foodservice class apply their knowledge to foodservice practices. Although portion sizes can influence energy and nutrient intakes in children, the actual portion sizes served by CCCs foodservice employees were inadequate and did not meet standards for serving size and nutrition. Thus, all CCCs foodservice employees need to receive foodservice education and be provided guidelines regarding portion sizes for children.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1547-1551
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• 2011

Bakery waste (BW) is much cheaper than barley (20 to 40% the price of barley). Bakery waste and barley grain have similar chemical composition; they contain 99 and 97% organic matter (OM), 1.1 and 1.8% fat, 18 and 15% neutral detergent fibre (NDF) and 14.0 and 14.5% crude protein (CP), respectively (DM basis). The objectives of this study were to determine the effect of substituting BW for barley grain in high concentrate fattening diets for lambs on nutrient intake, growth and carcass characteristics. Forty Awassi lambs (21.75${\pm}$1 kg) weaned at the age of 65 days were assigned randomly to four experimental fattening diets differing in BW ratio in a completely randomized design. The control diet (CON) contained 20, 60, 11, 7, and 2% (DM basis) wheat straw, barley grain, soybean meal, corn grain, and minerals and vitamin mix, respectively. Bakery waste substituted barley grain by 10, 20 and 30% of the diet DM in the LBW, MBW and HBW diets, respectively. The experiment lasted for 56 days. Dry matter intake (DMI) decreased (p<0.05) in LBW diet compared to the CON diet by approximately 10%. No further reduction in DMI was observed with the higher substitution levels. Metabolizable energy intake for the CON diet (3.6 Mcal/d) was also reduced (p<0.05) compared with LBW, MBW and HBW diets (3.4, 3.4 and 3.3 Mcal/d, respectively). Final body weight for lambs fed the CON diet (34.8 kg) was higher (p<0.05) compared with lambs fed the LBW, MBW and HBW diets (30.6, 32.0 and 31.1 kg, respectively). Growth rate for lambs fed the CON diet (232 g/d) was also higher (p<0.05) compared to lambs fed the LBW, MBW and HBW diets (170, 189, and 167 g/d, respectively). Feed to gain ratio was higher (p<0.05) for lambs fed the LBW, MBW and HBW diets (7.2, 6.6 and 7.3, respectively) compared with lambs that consumed the CON diet (5.7). Body weight gain cost was reduced by approximately 8% by the MBW and HBW diets as compared with the CON diet. Dressing percentage, full gut weight, empty gut weight and liver weights were all unaffected by the BW addition to the diets and averaged 48.9%, 6.8 kg, 2.8 kg and 0.444 kg, respectively. However, fat tail weight was increased (p<0.05) with the higher levels of the BW inclusion. In conclusion, substituting BW for barley grain reduced DMI and growth performance. However, when BW substituted barley grain at the 20 and 30% of the diet DM, body weight gain cost was reduced by approximately 8%.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.76-89
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• 2018

The distribution of the combined heat and power system is active as a solution to the instability of energy supply and environmental pollution caused by continuous industrial development. In Korea, the safety standards for combined heat and power system using a gas engine are insufficient therefore the study on this is needed. In this study, the safety performance and structural/material assessment items of domestic and international standards applied to the combined heat and power system were analyzed to carry out a standardization study on safety performance applicable to 20 kW gas engine combined heat and power system. In addition, the safety performance assessment (plan) of the gas engine combined heat and power system was derived by performing risk analysis and risk assessment using HAZOP. Assessment items include engine ignition systems related to safety performance, piping tight performance, watering and temperature rise performance, combustion performance, electrical efficiency, thermal efficiency, overall efficiency and humidity performance. Gas and water pipes, gas control and shut-off valves, durability, heat resistance, and cold resistance of metal or non-metallic materials related to the structure and materials of the gas engine combined heat and power systems.

• Journal of Nutrition and Health
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• v.55 no.5
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• pp.558-571
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• 2022

Purpose: The purpose of this study was to analyze the dietary intake of Korean adults with atopic dermatitis (AD) to determine whether the risk of developing AD was related to their diet. Methods: Among the participants in the 7th National Health and Nutrition Survey (2016 to 2018), 10,571 adults aged 19-64 were divided into AD (AD group, n = 366) and control groups (non-AD group, n = 10,205) to compare and analyze their nutrient intake status and Korean Healthy Eating Index (KHEI) score. Depending on the prevalence of AD, the nutrient intake, nutrient intake per 1,000 kcal, acceptable macronutrient distribution range, and KHEI score were tested for significance by correcting for age, sex, body mass index, education, marriage, occupation, residence area, physical activity, and energy intake variables that were derived for confounding factors. Results: The acceptable macronutrient distribution range for protein was lower in the AD group than in the non-AD group. Comparing the nutrient intake per 1,000 kcal, the intakes of protein, phosphorus, iron, and potassium of the AD group were significantly lower than those of the non-AD group. In the KHEI, the scores of total vegetables, vegetables excluding kimchi and pickles, meat, fish, eggs, and legumes of the AD group were significantly lower than those of the non-AD group. In addition, as these food intake scores increased, the risk of AD significantly decreased. Conclusion: In conclusion, adult AD patients had low intakes of vegetables, meat, fish, eggs, and legumes, and it was confirmed that high intakes of these foods may be associated with low AD risk. Therefore, we suggest that an adequate intake of vegetables and foods containing protein would be necessary for the management and treatment of AD in adults.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.2
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• pp.19-29
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• 2012

Numerous studies suggested that fish assemblage structure reflects the status of stream ecosystems. The status of streams integrity, including various trophic levels, water quality and habitat degradation, can be assessed by fish assemblages. In this study, we investigated the relationships between fish assemblages and streamline geometry of streams. Previous studies suggested that geomorphologic parameter can be a critical factor of permeability between adjacent two systems. From a landscape ecological perspective, edges may partially control the flow rate of energy between two adjacent systems. Thus, the Streamline geometry can be a geomorphologic parameter that exhibits the integrity of stream. We selected the Nakdong river for study areas, which is one of major rivers and the longest (525 km) River in South Korea. We used the revised IBI representing overall ecological characteristics of Korean fish assemblages and eight sub-assessment criteria of IBI, collected from 82 sampling sites in the Nakdong River. For calculating the Streamline geometry, we measured fractal dimension index that generally used in biology, ecology and landscape ecology. We used the digital land-use/land-cover map and generated a 1-km buffer for each sampling site and refined the shape of the Streamlines. Pearson correlation analyses were performed between Streamline geometry and IBI and sub-assessment criteria of IBI. The results show that IBI and eight sub-assessments of fish are significantly correlated with geometry of Streamline. The fractal dimension of Streamline geometry were related with IBI (r = 0.48) and six sub-assessments of IBI, including total number of native fish and native species, the number of riffle benthic species, sensitive species, tolerant species and native insectivore. Especially, the number of tolerant species(r = -0.52) and native insectivore(r = 0.52) show strong correlation with geometry of Streamline. These results indicate that lower Streamline geometry can result in poor fish assemblages, while higher geometry of Streamline can enhance fish assemblages by potentially supplying insects and better habitat conditions. We expect the results of our study to be useful for stream restoration and management. However, we see the necessity of study investigating the mechanisms how Streamline geometry affect fish assemblages.