• Korean journal of applied entomology
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• v.57 no.4
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• pp.261-269
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• 2018

The cowpea aphid Aphis craccivora Koch (Hemiptera: Aphididae) is a polyphagous species with a worldwide distribution. We investigated the temperature effects on development periods of nymphs, and the longevity and fecundity of apterous female of A. craccivora. The study was conducted at six constant temperatures of 10.0, 15.0, 20.0, 25, 30.0, and $32.5^{\circ}C$. A. craccivora developed successfully from nymph to adult stage at all temperatures subjected. The developmental rate of A. craccivora increased as temperature increased. The lower developmental threshold (LT) and thermal constant (K) of A. craccivora nymph stage were estimated by linear regression as $5.3^{\circ}C$ and 128.4 degree-days (DD), respectively. Lower and higher threshold temperatures (TL, TH and TH-TL, respectively) were calculated by the Sharpe_Schoolfield_Ikemoto (SSI) model as $17.0^{\circ}C$, $34.6^{\circ}C$ and $17.5^{\circ}C$. Developmental completion of nymph stages was described using a three-parameter Weibull function. Life table parameters were estimated. The intrinsic rate of increase was highest at $25^{\circ}C$, while the net reproductive rate was highest at $20^{\circ}C$. Biological characteristics of A. craccivora populations from different geographic areas were discussed.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.151-157
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• 2019

It was available to store both nymphs and adults of Geocoris pallidipennis at $5^{\circ}C$ for 3 weeks without negative effects on their survival, fecundity, and Bemisia tabaci predation. Fecundities of G. pallidipennis showed the tendency to be decreased with increasing cold storage duration, but up to 4 weeks, storage at $5^{\circ}C$ didn't affect their fecundity. When Micromus angulatus adults were stored at $5^{\circ}C$ with honey solution as preys, it was possible to store up to 140 days showing approximately 50% of cumulative survival, but over 2 week cold storage was not suitable for their fecundity. With the increase of cold storage duration, the aphid predation by M. angulatus decreased, but it could be possible to cold store until 5 weeks without any significant effect on their aphid predation. Thus, short term cold storage of G. pallidipennis and M. angulatus could be useful for inundative biological strategies.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.586-593
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• 2020

This study was conducted to investigate the biological characteristics of Phanuromyia ricaniae (Hemiptera: Platygastroidea), an egg parasitoid of Ricania sp. (Hemiptera: Ricaniidae) as a biological control agent to control Ricania sublimata. The developmental period of P. ricaniae was 3.8 days for eggs, 11.1 days for larvae, and 16.3 days for pupae at 25℃, and 3.4 days for eggs, 7.8 days for larvae, and 15.3 days for pupae at 30℃. Except for the larval stage, the developmental periods were not significantly different, but the egg-to-pupa period at 30℃ was significantly shorter than that at 25℃. P. ricaniae emerged at the photophase in 24 hours, but not at the scotophase. A higher emergence rate (34.5%) was seen from 10:00 to 12:00 after the lights were turned. The female-to-male ratio of P. ricaniae was 3:1. The longevity of P. ricaniae adults was 49.0 days for females and 44.0 days for males at 20℃, 27.6 days for females and 28.4 days for males at 25℃, and 18 days for females and 14.0 days for males at 30℃. Its longevity at a low temperature (20℃) was longer than that at higher temperatures (25 and 30℃). Adult females laid eggs during all days except from 00:00-02:00 (scotophase time). The ovipositional distribution rate was 26.1% from 20:00 to 22:00, which was the peak, and the next peak was 15.7% at 10:00 to 12:00. P. ricaniae showed arrhenotokous parthenogenesis in which unfertilized eggs develop into males. Therefore, the results suggest that P. ricaniae may be a biological control agent for R. sublimata.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.268-278
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• 2020

Flowering time has been put forward due to the recent abnormally warm winter, which often caused damages of flower buds by late frosts persistently. In the present study, cumulative chill unit and cumulative heat unit of Niitaka pear, which are required for releasing the endogenous dormancy and for flowering after breaking dormancy, respectively, were compared between flowering time prediction models used in South K orea. Observation weather data were collected at eight locations for the recent three years from 2018-2020. The dates of full bloom were also collected to determine the confidence level of models including DVR, mDVR and CD models. It was found that mDVR model tended to have smaller values (8.4%) of the coefficient of variation (cv) of chill units than any other models. The CD model tended to have a low value of cv (17.5%) for calculation of heat unit required to reach flowering after breaking dormancy. The mDVR model had the most accurate prediction of full bloom during the study period compared with the other models. The DVR model usually had poor skills in prediction of full bloom dates. In particular, the error of the DVR model was large especially in southern coastal areas (e.g., Ulju and Sacheon) where the temperature was warm. Our results indicated that the mDVR model had relatively consistent accuracy in prediction of full bloom dates over region and years of interest. When observation data for full bloom date are compiled for an extended period, the full bloom date can be predicted with greater accuracy improving the mDVR model further.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.312-326
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• 2020

Generation of weather forecasts at 100 m resolution through a statistical downscaling process was implemented by Korea Meteorological Administration Post- Processing (KMAPP) system. The KMAPP data started to be used in various industries such as hydrologic, agricultural, and renewable energy, sports, etc. Cheorwon area and Jeonbuk area have horizontal planes in a relatively wide range in Korea, where there are many complex mountainous areas. Cheorwon, which has a large number of in-situ and remotely sensed phenological data over large-scale rice paddy cultivation areas, is considered as an appropriate area for verifying KMAPP prediction performance in agricultural areas. In this study, the performance of predicting KMAPP temperature changes according to ecological changes in agricultural areas in Cheorwon was compared and verified using KMA and National Center for AgroMeteorology (NCAM) observations. Also, during the heat wave in Jeonbuk Province, solar radiation forecast was verified using Automated Synoptic Observing System (ASOS) data to review the usefulness of KMAPP forecast data as input data for application models such as livestock heat stress models. Although there is a limit to the need for more cases to be collected and selected, the improvement in post-harvest temperature forecasting performance in agricultural areas over ordinary residential areas has led to indirect guesses of the biophysical and phenological effects on forecasting accuracy. In the case of solar radiation prediction, it is expected that KMAPP data will be used in the application model as detailed regional forecast data, as it tends to be consistent with observed values, although errors are inevitable due to human activity in agricultural land and data unit conversion.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.13-23
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• 2021

In this study, we performed a Random Walker analysis to predict the Major Movement Paths of otters. The scope of the research was a simulation analysis with a radius of 7.5 km set as the final range centered on the Ansim-wetland in Daegu City, and a field survey was used to verify the model. The number of virtual otters was set to 1,000, the number of moving steps was set to 1,000 steps per grid, and simulations were performed on a total of 841 grids. As a result of the analysis, an average of 147.6 objects arrived at the boundary point under the condition of an interval of 50 m. As a result of the simulation verification, 8 points (13.1%) were found in the area where the movement probability was very high, and 9 points (14.8%) were found in the area where the movement probability was high. On the other hand, in areas with low movement paths probabilities, there were 8 points (13.1%) in low areas and 4 points (6.6%) in very low areas. Simulation verification results In areas with high otter values, the actual otter format probability was particularly high. In addition, as a result of investigating the correlation with the otter appearance point according to the unit area of the evaluation star of the movement probability, it seems that 6.8 traces were found per unit area in the area where the movement probability is the highest. In areas where the probability of movement is low, analysis was performed at 0.1 points. On the side where otters use the major movement paths of the river area, the normal level was exceeded, and as a result, in the area, 23 (63.9%), many form traces were found, along the major movement paths of the simulation. It turned out that the actual otter inhabits. The EN-Simulator analysis can predict how spatial properties affect the likelihood of major movement paths selection, and the analytical values are used to utilize additional habitats within the major movement paths. It is judged that it can be used as basic data such as to grasp the danger area of road kill in advance and prevent it.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.383-391
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• 2020

The vertical distribution and dispersion of the two-spotted spider mite, Tetranychus urticae and its predator, Phytoseiulus persimilis, were investigated within and between green pepper plants. We also tested the effect of an artificial bridge with threads on dispersal of P. persimilis between the plants. The extent of spread of T. urticae depended on its infested density and location. When 10 adults of T. urticae were inoculated on upper leaf, they stayed on the upper leaf until 5 days after inoculation. However, when 100 adults were inoculated on an upper leaf, they dispersed to the lower leaf within a day. In condition that 10 adults of T. urticae were inoculated on the lower leaf, they started to move toward upward within a day. In the absence of T. urticae, P. persimilis tended to move to the leaves where T. urticae was present when both T. urticae and P. persimilis were inoculated together within a plant. An artificial bridge with threads between two plants was helpful to disperse P. persimilis to neighboring plants. Therefore, it would be expected that the dispersal of P. persimilis can be promoted by supplying the artificial bridges among plants and by narrowing the distances between plants.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.374-390
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• 2021

Growth and yield of field vegetable crops would be affected by climate conditions, which cause a relatively large fluctuation in crop production and consumer price over years. The yield prediction system for these crops would support decision-making on policies to manage supply and demands. The objectives of this study were to compile literatures related to onion and garlic and to perform data-mining analysis, which would shed lights on the development of crop models for these major field vegetable crops in Korea. The literatures on crop growth and yield were collected from the databases operated by Research Information Sharing Service, National Science & Technology Information Service and SCOPUS. The keywords were chosen to retrieve research outcomes related to crop growth and yield of onion and garlic. These literatures were analyzed using text mining approaches including word cloud and semantic networks. It was found that the number of publications was considerably less for the field vegetable crops compared with rice. Still, specific patterns between previous research outcomes were identified using the text mining methods. For example, climate change and remote sensing were major topics of interest for growth and yield of onion and garlic. The impact of temperature and irrigation on crop growth was also assessed in the previous studies. It was also found that yield of onion and garlic would be affected by both environment and crop management conditions including sowing time, variety, seed treatment method, irrigation interval, fertilization amount and fertilizer composition. For meteorological conditions, temperature, precipitation, solar radiation and humidity were found to be the major factors in the literatures. These indicate that crop models need to take into account both environmental and crop management practices for reliable prediction of crop yield.

• Ecology and Resilient Infrastructure
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• v.9 no.1
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• pp.77-82
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• 2022

This study aims to understand how mobile and stationary air pollution sources affect the air quality and soil properties in urban parks. We selected three sites of urban parks in Seoul as follows: Ha-neul Park in Mapo-gu (Site_M), Ill-won Eco-Park in Gangnam-gu (Site_G), and Yangjae Citizen's Forest in Seocho-gu (Site_Y), and compared the results of each site's traffic volume, air quality concentration, and soil analysis. Traffic volume was high in Site_M, followed by Site_G and Y; Site_M and G were closer to the resource recovery facility than Site_Y. Hence, we hypothesized that PM and NO₂ concentrations in the atmosphere were higher in Site_M than Site_G and Y, causing different soil nitrogen content among sites due to different atmospheric deposition. Consistent with our hypothesis, the concentrations of PM2.5 and NO₂ were higher in Site_M and G than Site_Y, while Site_Y had higher PM10 than other sites. The soil NO₃^- contents showed no significant difference among three sites, whereas the soil NH₄+ content was extremely high in Site_Y. This high content of soil NH₄⁺ is thought to be due to acidification from excessive fertilization. Lower soil pH of Site_Y further supported the evidence of heavy fertilization in this site. Overall nitrogen dynamics implies that soil nitrogen status is more influenced by park management such as fertilization rather than atmospheric deposition. Despite of lower soil NH₄⁺ content of Site_M and G than Y, vegetation vitality looked similar among three sites. This indirectly indicates that excessive fertilizer input in urban park management needs to be reconsidered. This study showed that even if the air quality was different due to mobile and stationary sources, it did not directly affect the soil nitrogen nutrient status of the adjacent urban park.

• Communications of Mathematical Education
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• v.36 no.3
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• pp.313-334
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• 2022

The purpose of this study is to analyze the changes in mathematical learning through applying STEAM education according to social needs for out-of-school youth. For this purpose, we developed a teaching and learning model and program for mathematics and music STEAM education, and we implemented and analyzed the changes of affective area and problem-solving strategies. The analysis results of characteristic in affective area are as follows: first, the activity-oriented class of mathematics and music STEAM education aroused interest in mathematics. Second, providing opportunities for mathematics and music STEAM education instilled a positive perception of the value of mathematics and STEAM education. Third, the autonomous communication-oriented learning environment of mathematics and music STEAM education improved confidence and motivation to learn in mathematics. The analysis results of the characteristic in problem-solving strategy are as follows: first, through the STEAM education with mathematics and music, a conceptual understanding of internally and externally dividing points was formed, and a given problem was expressed and solved in a formula. Second, the functional correspondence relationship was understood, and the given problem was described and solved with symbols associated with the function. The suggestions of the study are as follows: first, based on the teaching and learning model and results of this study, various STEAM education programs for out-of-school youth should be developed and expanded to foster future competencies and provide new changes for out-of-school youth. Second, it can be used for research on the development of teaching and learning materials for convergence elective subjects in the high school credit system by referring to the mathematics and music convergence STEAM program of this study. As the subjects and fields of STEAM education are diversified and organized, students in need of receiving educational opportunities will be reduced, and there will be a world where the name of out-of-school youth and alternative education will not be necessary. Therefore, it is expected that development of teaching and learning programs created by interest in education of out-of-school youth will be used as an innovative idea in school education to achieve a virtuous cycle.