웹 카메라를 이용한 시설 내 국화생산 광 환경 원격 모니터링

정선옥(Sun-Ok Chung),김용주(Yong-Joo Kim),이규호(Kyu-Ho Lee),성남석(Nam-Seok Sung),이철휘(Cheol-Hwi Lee),노현권(Hyun-Kwon Noh) 충남대학교 농업과학연구소 2015 농업과학연구 Vol.42 No.4

Increase of national family income improved demand of high-quality and year-round horticultural products including chrysanthemum. To meet these demand, farmers have introduced protected facilities, such as greenhouses, of which environmental conditions could be monitored and controlled. Environment management up to three weeks after transplanting is critical for chrysanthemum quality. Artificial lighting and light-blocking screen are especially important for long-day (day period > 13 hours) and short-day (night period > 13 hours) treatments. In this study, a web-camera was installed, and the image was obtained and transmitted to mobile phones to monitor the status of 3-wavelength(RGB) lighting environments. RGB pixel values were used to determine malfunctioning of the lighting lamps, and leaking out and incoming illumination status during short-day and long-day treatment periods. Normal lighting lamps provided RGB pixel values of 240~255. During long-day treatment period, G pixel values were useful to detect abnormal lighting conditions (e.g., leaking). During short-day treatment period, R pixel values were useful to determine incoming light (e.g., sun-light). Results of this study would provide useful information for remote monitoring of light conditions for protected chrysanthemum production under artificial lights.

Modeling of CO₂ Emission from Soil in Greenhouse

Dong Hoon Lee,Kyou Seung Lee,Chang Hyun Choi,Yong Jin Cho,Jong-Myoung Choi,Sun-Ok Chung 한국원예학회 2012 원예과학기술지 Vol.30 No.3

Greenhouse industry has been growing in many countries due to both the advantage of stable year-round crop production and increased demand for fresh vegetables. In greenhouse cultivation, CO₂ concentration plays an essential role in the photosynthesis process of crops. Continuous and accurate monitoring of CO₂ level in the greenhouse would improve profitability and reduce environmental impact, through optimum control of greenhouse CO₂ enrichment and efficient crop production, as compared with the conventional management practices without monitoring and control of CO₂ level. In this study, a mathematical model was developed to estimate the CO₂ emission from soil as affected by environmental factors in greenhouses. Among various model types evaluated, a linear regression model provided the best coefficient of determination. Selected predictor variables were solar radiation and relative humidity and exponential transformation of both. As a response variable in the model, the difference between CO₂ concentrations at the soil surface and 5-㎝ depth showed are latively strong relationship with the predictor variables. Segmented regression analysis showed that better models were obtained when the entire daily dataset was divided into segments of shorter time ranges, and best models were obtained for segmented data where more variability in solar radiation and humidity were present (i.e., after sun-rise, before sun-set) than other segments. To consider time delay in the response of CO₂ concentration, concept of time lag was implemented in the regression analysis. As a result, there was an improvement in the performance of the models as the coefficients of determination were 0.93 and 0.87 with segmented time frames for sun-rise and sun-set periods, respectively. Validation tests of the models to predict CO₂ emission from soil showed that the developed empirical model would be applicable to real-time monitoring and diagnosis of significant factors for CO₂ enrichment in a soil-based greenhouse.

Modeling of CO₂ Emission from Soil in Greenhouse

Lee, Dong-Hoon,Lee, Kyou-Seung,Choi, Chang-Hyun,Cho, Yong-Jin,Choi, Jong-Myoung,Chung, Sun-Ok Korean Society of Horticultural Science 2012 원예과학기술지 Vol.30 No.3

Greenhouse industry has been growing in many countries due to both the advantage of stable year-round crop production and increased demand for fresh vegetables. In greenhouse cultivation, $CO_2$ concentration plays an essential role in the photosynthesis process of crops. Continuous and accurate monitoring of $CO_2$ level in the greenhouse would improve profitability and reduce environmental impact, through optimum control of greenhouse $CO_2$ enrichment and efficient crop production, as compared with the conventional management practices without monitoring and control of $CO_2$ level. In this study, a mathematical model was developed to estimate the $CO_2$ emission from soil as affected by environmental factors in greenhouses. Among various model types evaluated, a linear regression model provided the best coefficient of determination. Selected predictor variables were solar radiation and relative humidity and exponential transformation of both. As a response variable in the model, the difference between $CO_2$ concentrations at the soil surface and 5-cm depth showed are latively strong relationship with the predictor variables. Segmented regression analysis showed that better models were obtained when the entire daily dataset was divided into segments of shorter time ranges, and best models were obtained for segmented data where more variability in solar radiation and humidity were present (i.e., after sun-rise, before sun-set) than other segments. To consider time delay in the response of $CO_2$ concentration, concept of time lag was implemented in the regression analysis. As a result, there was an improvement in the performance of the models as the coefficients of determination were 0.93 and 0.87 with segmented time frames for sun-rise and sun-set periods, respectively. Validation tests of the models to predict $CO_2$ emission from soil showed that the developed empirical model would be applicable to real-time monitoring and diagnosis of significant factors for $CO_2$ enrichment in a soil-based greenhouse.

Causes of a Low Measles Seroprevalence among Young Healthcare Workers in Korea

Chung Hyemin,Cho Sung-Kwan,Joo Jiyeon,Kim Sun-Kyung,Kim Eun Ok,Kim Min Jae,Chong Yong Pil,Choi Sang-Ho,Lee Sang-Oh,Kim Yang Soo,Jung Jiwon,Kim Sung-Han 대한감염학회 2023 Infection and Chemotherapy Vol.55 No.3

Background: Sporadic measles outbreaks have continued to occur in Korea, mainly in adults in their 20s and 30s, most notably in 2014 and 2019. We here evaluated the possible causes of a low seroprevalance of measles by testing young healthcare workers (HCWs). Materials and Methods: This study was conducted in a 2,743-bed tertiary-care hospital in Seoul between 2020 and 2021. We performed a measles antibody test (chemiluminescence immunoassay), measured the IgM/IgG index ratio, and conducted an avidity test at 1-month after Measles-Mumps-Rubella (MMR) vaccination in HCWs who had been seronegative for measles. Measles vaccination histories were obtained from the national vaccine registry. Results: Of the 3,173 HCWs newly employed in our hospital during the study period, 54 with a negative measles IgG at commencement were enrolled. Thirty six (67%) of these subjects were female, and the median age was 25 years (interquartile range [IQR]: 24 - 27). Fourty nine (91%) showed seroconversion at 1 month after the first vaccination. Of these individuals, 38 received both measles IgM and IgG test, and all had an IgM/IgG index <1. Of the 49 seroconverters, all HCWs showed a high avidity index. According to the national immunization registry, 45 (83%) received at least 2 doses of an MMR vaccination. Conclusion: Secondary vaccine failure may underlie vaccine failure in young Korean adults. HCWs born after 1985 with a negative measles antibody may need only a single dose booster vaccination rather than a 2-dose vaccination regimen.

Evaluation of the therapeutic effect of temozolomide in orthotopic brain tumor xenograft mice using non-invasive molecular imaging modalities

Ok-Sun Kim,Eun Sang Lee,Jang Woo Park,Hye Kyung Chung 한국실험동물학회 2018 한국실험동물학회 학술발표대회 논문집 Vol.2018 No.1

Spatial Variability of Soil Properties using Nested Variograms at Multiple Scales

Chung, Sun-Ok,Sudduth, Kenneth A.,Drummond, Scott T.,Kitchen, Newell R. Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.4

Purpose: Determining the spatial structure of data is important in understanding within-field variability for site-specific crop management. An understanding of the spatial structures present in the data may help illuminate interrelationships that are important in subsequent explanatory analyses, especially when site variables are correlated or are a combined response to multiple causative factors. Methods: In this study, correlation, principal component analysis, and single and nested variogram models were applied to soil electrical conductivity and chemical property data of two fields in central Missouri, USA. Results: Some variables that were highly correlated, or were strongly expressed in the same principal component, exhibited similar spatial ranges when fitted with a single variogram model. However, single variogram results were dependent on the active lag distance used, with short distances (30 m) required to fit short-range variability. Longer active lag distances only revealed long-range spatial components. Nested models generally yielded a better fit than single models for sensor-based conductivity data, where multiple scales of spatial structure were apparent. Gaussian-spherical nested models fit well to the data at both short (30 m) and long (300 m) active lag distances, generally capturing both short-range and long-range spatial components. As soil conductivity relates strongly to profile texture, we hypothesize that the short-range components may relate to the scale of erosion processes, while the long-range components are indicative of the scale of landscape morphology. Conclusion: In this study, we investigated the effect of changing active lag distance on the calculation of the range parameter. Future work investigating scale effects on other variogram parameters, including nugget and sill variances, may lead to better model selection and interpretation. Once this is achieved, separation of nested spatial components by factorial kriging may help to better define the correlations existing between spatial datasets.

Analysis of Spatial Variability in a Korean Paddy Field Using Median Polish Detrending

Chung, Sun-Ok,Jung, In-Kyu,Sung, Je-Hoon,Sudduth, Kenneth A.,Drummond, Scott T. Korean Society for Agricultural Machinery 2008 바이오시스템공학 Vol.33 No.5

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

Evaluation of a Community-Based Program for Breast Self-Examination Offered by the Community Health Nurse Practitioners in Korea

Chung Yul Lee,Hee Soon Kim,Il Sun Ko,Ok Kyung Ham 한국간호과학회 2003 Journal of Korean Academy of Nursing Vol.33 No.8

Sensing Technologies for Grain Crop Yield Monitoring Systems: A Review

Chung, Sun-Ok,Choi, Moon-Chan,Lee, Kyu-Ho,Kim, Yong-Joo,Hong, Soon-Jung,Li, Minzan Korean Society for Agricultural Machinery 2016 바이오시스템공학 Vol.41 No.4

Purpose: Yield monitoring systems are an essential component of precision agriculture. They indicate the spatial variability of crop yield in fields, and have become an important factor in modern harvesters. The objective of this paper was to review research trends related to yield monitoring sensors for grain crops. Methods: The literature was reviewed for research on the major sensing components of grain yield monitoring systems. These major components included grain flow sensors, moisture content sensors, and cutting width sensors. Sensors were classified by sensing principle and type, and their performance was also reviewed. Results: The main targeted harvesting grain crops were rice, wheat, corn, barley, and grain sorghum. Grain flow sensors were classified into mass flow and volume flow methods. Mass flow sensors were mounted primarily at the clean grain elevator head or under the grain tank, and volume flow sensors were mounted at the head or in the middle of the elevator. Mass flow methods used weighing, force impact, and radiometric approaches, some of which resulted in measurement error levels lower than 5% ($R^2=0.99$). Volume flow methods included paddle wheel type and optical type, and in the best cases produced error levels lower than 3%. Grain moisture content sensing was in many cases achieved using capacitive modules. In some cases, errors were lower than 1%. Cutting width was measured by ultrasonic distance sensors mounted at both sides of the header dividers, and the errors were in some cases lower than 5%. Conclusions: The design and fabrication of an integrated yield monitoring system for a target crop would be affected by the selection of a sensing approach, as well as the layout and mounting of the sensors. For accurate estimation of yield, signal processing and correction measures should be also implemented.

Influence of environmental factors such as temperature, humidity, and light on pollen longevity of GM- and non-GM zoysiagrass plants (Zoysia japonica Steud)

Ok-Chul Chung,Hong-Gyu Kang,Tae-Woong Bae,Hyeon-Jin Sun,Jeong-Keun Choi,Pyung Ok Lim,Hyo-Yeon Lee 한국육종학회 2012 한국육종학회 심포지엄 Vol.2012 No.07

Daily shedding pattern and longevity of pollen are important consideration for the evaluation of gene flow of transgenic plants. During the day, the pollen shedding pattern of zoysiagrass was determined in the lawn by using a device to collect airborne pollen on a glass slide, resulting that the pollen grains were released predominantly between 7:00 and 9:00. The result was also supported by in vitro pollen germination test, which was performed with pollens collected from 1:00 through 24:00 at 1h interval. Influence of temperature and humidity on pollen longevity was determined by germinating pollen at 25°C after incubating them for 10, 30, 60, and 180 min under different temperatures and humidity with pollen of zoysiagrass that opened freshly at about 9:00. The result showed that pollen longevity of zoysiagrass was sensitive to change of temperature and humidity and longest under the temperture and humidity of 15-20°C and 80-99%, respectively. Under natural conditions with the same method as upper controlled conditions, was determined pollen longevity. Under sunny atmospheric conditions, pollen longevity decreased to 20% in 60 min, with a complete extinction in 120 min. Under cloudy atmospheric conditions, pollen remained viable up to 450 min, with about 20% longevity after 360 min. No significant difference was found between GM and non-GM plants in their pollen longevity.