• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.1
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• pp.154-167
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• 2019

As urban heat environment problems occur due to climate change, urban thermal environmental problems such as heat waves and tropical nights are becoming more serious in cities. In South Korea, forest areas favorable for generating cold air account for about 63 percent of the land area. Furthermore, the Jeongmaek, the axis of the main mountain ranges of Korea, is located close to the cities. Hence, the management of cold air is an effective way to improve the thermal environment of Korean cities. We selected the Nak-nam Jeongmaek located in the southern part of Korean Peninsular as well as two cities (Jinju-si and Sancheong-gun) located at the Jeongmaek to analyze its cold air characteristics and suggest management strategies of cold air. We used KALM (Kaltluftabflussmodell), a cold air simulation model developed in Germany and identified both the cold air flow and the height of cold air layer generated during 6 hours at night. As a result, the cold air flow generated in the Jeongmaek became clear and the height of cold air layer increased with time. Based on the results, we proposed management plans to maintain and expand the cold air flow. For example, forest areas with active cold air generation were designated as 'cold air conservation areas', and areas requiring management for good cold air flow were as 'cold air management areas'. This study is expected to be useful for establishing systematic urban ventilation plan to improve thermal environment in Korea cities.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.11-22
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• 2019

The objective of this study was to improve the cross-sectional area and height estimation method using stream width. Stream water levels should be calculated together to simulate inundation of agricultural land. However, cross-sectional survey data of small rural rivers are insufficient. The previous study has developed regression equations between the width and the cross-sectional area and between the width and the height of stream cross-section, but can not be applied to a wide range of stream widths. In this study, cross-sectional survey data of 6 streams (Doowol, Chungmi, Jiseok, Gam, Wonpyeong, and Bokha stream) were collected and divided into upstream, midstream and downstream considering the locations of cross-sections. The regression equations were estimated using the complete data. $R^2$ between the stream width and cross-sectional area was 0.96, and $R^2$ between width and height was 0.81. The regression equations were also estimated using divided data for upstream, midstream and downstream considering the locations of cross-sections. The range of $R^2$ between the stream width and cross-sectional area was 0.86 - 0.91, and the range of $R^2$ between width and height was 0.79 ? 0.92. As a result of estimating the cross-sections of 6 rivers using the regression equations, the regression equations considering the locations of cross-sections showed better performance both in the cross-sectional area and height estimation than the regression equations estimated using the complete data. Hydrologic Engineering Center - River Analysis System (HEC-RAS) was used to simulate the flood stage analysis of the estimated and the measured cross-sections for 50-year, 100-year, and 200-year frequency floods. As a result of flood stage analysis, the regression equations considering the locations of cross-sections also showed better performance than the regression equations estimated using the complete data. Future research would be needed to consider the factors affecting the cross-sectional shape such as river slope and average flow velocity. This study can be useful for inundation simulation of agricultural land adjacent to an unmeasured stream.

• Animal Bioscience
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• v.35 no.5
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• pp.648-658
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• 2022

Objective: The identification of nonlinear mixed models that describe the growth trajectory of New Zealand rabbits was performed based on weight records and carcass measures obtained using ultrasonography. Methods: Phenotypic records of body weight (BW) and loin eye area (LEA) were collected from 66 animals raised in a didactic-productive module of cuniculture located in the southern Piaui state, Brazil. The following nonlinear models were tested considering fixed parameters: Brody, Gompertz, Logistic, Richards, Meloun 1, modified Michaelis-Menten, Santana, and von Bertalanffy. The coefficient of determination (R²), mean squared error, percentage of convergence of each model (%C), mean absolute deviation of residuals, Akaike information criterion (AIC), and Bayesian information criterion (BIC) were used to determine the best model. The model that best described the growth trajectory for each trait was also used under the context of mixed models, considering two parameters that admit biological interpretation (A and k) with random effects. Results: The von Bertalanffy model was the best fitting model for BW according to the highest value of R² (0.98) and lowest values of AIC (6,675.30) and BIC (6,691.90). For LEA, the Logistic model was the most appropriate due to the results of R² (0.52), AIC (783.90), and BIC (798.40) obtained using this model. The absolute growth rates estimated using the von Bertalanffy and Logistic models for BW and LEA were 21.51g/d and 3.16 cm², respectively. The relative growth rates at the inflection point were 0.028 for BW (von Bertalanffy) and 0.014 for LEA (Logistic). Conclusion: The von Bertalanffy and Logistic models with random effect at the asymptotic weight are recommended for analysis of ponderal and carcass growth trajectories in New Zealand rabbits. The inclusion of random effects in the asymptotic weight and maturity rate improves the quality of fit in comparison to fixed models.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.193-205
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• 2009

Typhoons occurred in the tropical Pacific region, these might be affected the Korea moving toward north. The strong winds and the heavy rains by the typhoons caused a natural disaster in Korea. In the research, the heavy rainfall events based on typhoons were evaluated quantitative through various statistical techniques. First, probability precipitation and typhoon probability precipitation were compared using frequency analysis. Second, EST probability precipitation was calculated by Empirical Simulation Techniques (EST). Third, NL probability precipitation was estimated by coupled Nonparametric monte carlo simulation and Locally weighted polynomial regression. At the analysis results, the typhoons can be effected Gangneung and Mokpo stations more than other stations. Conversely, the typhoons can be effected Seoul and Inchen stations less than other stations. Also, EST and NL probability precipitation were estimated by the long-term simulation using observed data. Consequently, major hydrologic structures and regions where received the big typhoons impact should be review necessary. Also, EST and NL techniques can be used for climate change by the global warming. Because, these techniques used the relationship between the heavy rainfall events and the typhoons characteristics.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.127-140
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• 2011

Research achievement of Korean geographers on karst studies was evaluated based on the number of publications for the past fifty years, which were divided into four main periods, including beginning, youth, growth, and maturity stages. The descriptive statistics of research papers published in major geography journals were computed and these articles were classified according to their main subjects and study areas. The role of moisture is particularly important in Karst geomorphology compared to the other geomorphological fields. The morphology, landscape, and formation processes of tropical and temperate karst are different from each other, and the regional and altitudinal characteristics of karst environments are significantly diverse. Thus, it is likely that the detailed records of climatic changes are preserved in the northeast Asian karst landform. Since karst geomorphology can be a major cause of natural hazards, such as collapsed surfaces or subsidence, which are associated with anthropogenic activities, including underground-water pumping and land use, education and training of physical geographers, specializing on monsoon effects, distributions of limestone, and soil characteristics, are critical issues to foster the capacity of disaster management in the nation. Moreover, knowing that the unique and spectacular landscape of karst geomorphology is a valuable, natural resource of tourism and has aesthetic values on its own, contributions of geographers to the introduction, conservation, research, and development of karst environment should be emphasized.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.79-92
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• 2024

Global warming is a key challenge subjecting animals to heat stress conditions resulting in multiple physiological alterations in tropical climate. Dietary approach seems to be the more friendly approach to curb the adverse effects of heat stress in rabbits. Some herbs have been categorized to have high potential for promotion of immune responses for amelioration of heat stress. Thus, this research aims to evaluate the potential of Mistletoe (Viscum album), Moringa (Moringa oleifera) and Phyllanthus (Phyllanthus amarus) leaf meal as herbal supplements for the alleviation of heat stress in female rabbits by measuring improvement in sex and stress hormonal responses in serum biochemistry. 80 Rabbit does were exposed to 4 dietary groups supplemented with each of Mistletoe, Moringa, Phyllanthus and a control in an 84-day trial at the summit of thermal stress in South west Nigeria. Growth indices were monitored throughout the study, blood samples were compiled at the end of the trial to assess serum biochemistry, stress and sex hormonal responses of the Does using standard protocols. The results revealed that final weight and weight gain of Does fed on Phyllanthus were significantly (p < 0.05) higher (11.46% and 14.25%, respectively) than Does on control. The herbal supplements enhance glucose, protein, albumin and globulin, reduced cholesterol, and creatinine of Does under heat stress conditions. Among the herbal treatment groups, mistletoe, moringa and phyllanthus had 12.42%, 18.39% and 16.90%, respectively, lower corticosterone than control groups which had 39.76ng/ml. Triiodothyronine of Does fed control were significantly (p < 0.05) lower than Does on Moringa oleifera and Phyllanthus amarus supplements. Estradiol and Follicle stimulating hormone of rabbit Does fed on moringa supplement were significantly (p < 0.05) higher than other treatments. In conclusion, the herbal supplements tend to mitigate the detrimental outcome of thermal stress on Does by suppressing stress hormones. Moringa oleifera and Phyllanthus amarus enhanced sex hormones while Phyllanthus amarus confered growth promoting effects on the Does.

• Atmosphere
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• v.17 no.4
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• pp.471-481
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• 2007

Temperature and precipitation, particularly August and summer, in the Korean peninsular are analyzed. The analyzed period is 1973-2007 for the Korean peninsular (that is, 60 meteorological station average). In addition, 100 year record (1908-2007) of temperature and precipitation in Seoul are also analyzed. Results indicate that the temperatures (mean, maximun, and minimum) of August and summer of 2007, both in Korean peninsular and Seoul, are higher than normal. The increasing rate of minimum temperature for the August and summer during the period from 1973 to 2007 shows greater than the mean and maximum temperature both in Korean peninsular and Seoul due to the global warming and urbanization. Number of tropical night days, defined by the days with above $25^{\circ}C$ in minimum temperature, shows increasing trend both in August and summer from 1973 to 2007 due to the combination effect of the global warming and urbanization. The amount of precipitation, both in August and summer, for Korean peninsular and Seoul shows increasing trend from 1973 to 2007, and 1908 to 2007, respectively. Amount of precipitation and rainy days, both August and summer, during 2000s show greater than those of the 1970s both in Korean peninsular and Seoul. Extreme rainy days (greater than 120mm/day, greater than 80mm/day, greater than 30mm in any 1-hour period and greater than 10mm in any 10-minute period) show increasing trend from 1973 to 2007 for both in August and in summer.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.226-235
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• 2017

Roselle (Hibiscus sabdariffa L.) is a shrub which grows well in a tropical climate. There are large amounts of anthocyanins, organic acids and other compounds in roselle. Mostly, roselle is cultivated to use its red calyx. Its calyx is used as a natural food colorant and commonly consumed as a tea. This quality study was conducted to investigate the characteristics and antioxidant activities of Sulgidduck with roselle calyx powder. Four samples and a control were made with different ratios of added roselle calyx powder (0.5%, 1%, 1.5%, 2%). The moisture content of the 0.5%-sample was the highest as 40.60%, and that of the 2%-sample was the lowest as 37.37%. The pH of samples significantly decreased from 6.26 to 3.65 as the amount of roselle calyx powder increased (p<0.05). The L-value of samples also significantly decreased (p<0.05). In contrast, a-value and ${\Delta}E$ of samples significantly increased with elevated amounts of roselle calyx powder (p<0.05). The b-value of roselle calyx added Sulgidduck samples significantly increased compared to the control (p<0.05). Hardness and chewiness of Sulgidduck samples with added roselle calyx also significantly increased compared to the control (p<0.05). Cohesiveness of Sulgidduck samples with roselle calyx significantly decreased compared to control (p<0.05), with the exception of the 1% sample. There were no significant differences in springiness among samples. Total phenolic contents significantly increased when roselle calyx powder was added above a level of 1.5% (p<0.05). The flavonoid content of the control was the lowest as 0.73. ABTS radical scavenging activity significantly increased with increasing amounts roselle calyx powder (p<0.05). The 2%-sample got the lowest sensory preference scores in sweetness and overall acceptability. In contrast, the control and 1%-sample got the highest sensory preference scores. Based on these study findings, addition of 1% roselle calyx powder optimized the preparation of Sulgidduck and roselle calyx is therefore a useful natural colorant and antioxidant.

• Korean journal of applied entomology
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• v.55 no.1
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• pp.17-26
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• 2016

Climate change has been regarded as one of main factors to change Korean insect pest fauna. Especially, a global warming model predicts to expand habitat for insect pests originated from tropical or subtropical regions. Two insect pests, the beet armyworm (Spodoptera exigua) and the diamondback moth (Plutella xylostella), are known to overwinter in some greenhouse conditions without diapause induction in Korea. There was a clear difference between these two insects in seasonal occurrence. P. xylostella occurred only at early spring and fall seasons, but did not occur during summer. In contrast, S. exigua maintained their occurrence from late spring to fall seasons. This study set up a hypothesis that the difference in the seasonal occurrence may be resulted from variation in susceptibility to high temperature. To test the hypothesis, heat tolerance was compared between these two insects. Exposure to $42^{\circ}C$ for 40 min killed 100% individuals of P. xylostella larvae. However, most larvae of S. exigua survived in response to $42^{\circ}C$ even for 80 min. Heat tolerance varied among developmental stages in both insects. Highest tolerant stages were $4^{th}$ instar larvae and adults for P. xylostella, but $1^{st}$ instar larvae for S. exigua. Pre-exposure to $37^{\circ}C$ for 30 min significantly increased heat tolerance in both insects. Induction of heat tolerance accompanied with significant increase of glycerol contents in the hemolymph in both insects and up-regulation of three heat shock protein expressions in S. exigua. These results suggest that the differential susceptibility to high temperature explains the disappearance of P. xylostella during summer, at which S. exigua maintains its occurrence.