• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.597-602
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• 2016

Recent clinical field utilizes the aluminium filter in order to reduce the low-energy photons. However, the usage of the filter can cause adverse effect on the image quality because of the scattered dose that is generated by X-ray hardening phenomenon. Further, usage of filter with improper thickness can be a reason of dose creep phenomenon where unnecessary exposure is generated towards the patient. In this study, the author evaluated the RMS and the RSD analysis in order to have a quantitative evaluation for the effect of forward scattering dose by the filter on the image. as a result of the study, the FSR and the RSD was increased together with the increasing of thickness of the filter. In this study the RSD means the standard deviation of the mean value is relatively size. It can be understood that the signal-to-noise ratio decreases when the average value is taken as a signal and the standard deviation is judged as a noise. The signal-to-noise ratio can understanding as index of resolution at image. Based on these findings, it was quantitatively verified that there is a correlation of the image quality with the FSR by using an additional filter. The results, a 2.5 mmAl which is as recommended by NCRP in the tube voltage of 70 kVp or more showed the 14.6% on the RSD when the filter was not in used. these results are considered able to be utilized as basic data for the study about the filter to improve the quality of the image.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.67-81
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• 2005

Recently, the interest and research on the development of new application services such as the Location Based Service and Telemetics providing the emergency service, neighbor information search, and route search according to the development of the Geographic Information System have been increasing. User's search in the spatio-temporal database which is used in the field of Location Based Service or Telemetics usually fixes the current time on the time axis and queries the spatial and aspatial attributes. Thus, if the range of query on the time axis is extensive, it is difficult to efficiently deal with the search operation. For solving this problem, the snapshot, a method to summarize the location data of moving objects, was introduced. However, if the range to store data is wide, more space for storing data is required. And, the snapshot is created even for unnecessary space that is not frequently used for search. Thus, non storage space and memory are generally used in the snapshot method. Therefore, in this paper, we suggests the Hash-based Spatio-Temporal Clustering Algorithm(H-STCA) that extends the two-dimensional spatial hash algorithm used for the spatial clustering in the past to the three-dimensional spatial hash algorithm for overcoming the disadvantages of the snapshot method. And, this paper also suggests the knowledge extraction algorithm to extract the knowledge for the path search of moving objects from the past location data based on the suggested H-STCA algorithm. Moreover, as the results of the performance evaluation, the snapshot clustering method using H-STCA, in the search time, storage structure construction time, optimal path search time, related to the huge amount of moving object data demonstrated the higher performance than the spatio-temporal index methods and the original snapshot method. Especially, for the snapshot clustering method using H-STCA, the more the number of moving objects was increased, the more the performance was improved, as compared to the existing spatio-temporal index methods and the original snapshot method.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.29-36
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• 2007

This study was carried out to develop a water quality simulation model for the evaluation of an ungauged watershed. For this purpose, the WASP5 model was selected and modified. The model consists of three sub-models, LOAD-M, DYN-M, and EUT-M. LOAD-M, an empirical model, estimates runoff loadings using point and non-point source data of villages. The Geum River Estuary watershed was selected to calibrate and verify the Modified-WASP5. The LOAD-M model was established using field data of water quality and quantity at the gauging stations of the watershed and was applied to the ungauged watersheds, taking the watershed properties into consideration. The result of water quality simulation using Modified-WASP5 shows that the observed average BOD data from Gongju and Ganggyeong were 2.6 mg/L and 2.8 mg/L, and the simulated data were 2.5 mg/L and 2.4 mg/L, respectively. Generally, simulation results were in good agreement with the observed data. This study focused on formulating an integrated model for evaluating ungauged watersheds. Even though simulation results varied slightly due to limited availability of data, the model developed in this study would be a useful tool for the assessment and management of ungauged watersheds.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.883-893
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• 2019

In this study, crop coefficients were calculated in two different methods and the results were evaluated. In the first method, appropriateness of GLDAS-based evapotranspiration was evaluated by comparing it with observed data of Cheongmi-cheon (CMC) Flux tower. Then, crop coefficient was calculated by dividing actual evapotranspiration with potential evapotranspiration that derived from GLDAS. In the second method, crop coefficient was determined by using MLR (Multiple Linear Regression) analysis with vegetation index (NDVI, EVI, LAI and SAVI) derived from MODIS and in-situ soil moisture data observed in CMC, In comparison of two crop coefficients over the entire period, for each crop coefficient GLDAS K_c and SM&VI K_c, shows the mean value of 0.412 and 0.378, the bias of 0.031 and -0.004, the RMSE of 0.092 and 0.069, and the Index of Agree (IOA) of 0.944 and 0.958. Overall, both methods showed similar patterns with observed evapotranspiration, but the SM&VI-based method showed better results. One step further, the statistical evaluation of GLDAS K_c and SM&VI K_c in specific period was performed according to the growth phase of the crop. The result shows that GLDAS K_c was better in the early and mid-phase of the crop growth, and SM&VI K_c was better in the latter phase. This result seems to be because of reduced accuracy of MODIS sensors due to yellow dust in spring and rain clouds in summer. If the observational accuracy of the MODIS sensor is improved in subsequent study, the accuracy of the SM&VI-based method will also be improved and this method will be applicable in determining the crop coefficient of unmeasured basin or predicting the crop coefficient of a certain area.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.62-69
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• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.94-97
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• 2014

Purpose: Standardized uptake value (SUV) is a simple semi-quantitative method that can measure the ratio of the tissue radioactivity between the tumor and normal. SUV is commonly used in PET/CT, however, SUV is affected by various factor. The purpose of this study was to evaluate the impact of the residual activity on SUV depending on the location of catheter insertion device post injection. Materials and Methods: NEMA IEC Body Phantom was imaged using a Discovery 600 PET scanner. In 22 mm diameter sphere, the different activity of $^{18}F-FDG$ (7.4, 14.8, 22.2, 29.6, 37, 55.5 MBq) was filled and background was filled with $^{18}F-FDG$ (5.7 kBq/mL). We scaned the phantom on the assumption that the radioactivity in sphere was residual activity in insertion device. Simulation of PET was divided into three groups based on the location of sphere in Scan FOV (SFOV); inclusion, 1/2 inclusion and exclusion group. Results: Among three groups, the group of excluded sphere showed the highest SUV regardless of the amount of $^{18}F-FDG$ activity. In case of 7.4 MBq, average SUV of inclusion group, 1/2 inclusion and exclusion group was 0.780, 0.840 and 0.896 respectively. However, average SUV of 55.5 MBq showed 0.372, 0.460 and 0.508 with same order. Depend on residual radioactivity in the sphere and position of sphere, the SUV was different minimum of 10.4%, maximum of 62.8%. Conclusion: This study showed that SUV is underestimated as the residual radio-activity is increased. In addition, SUV was a changed according to the position of residual radio-activity. And among the position, exclusion group showed the difference of SUV was lowest. If we measure the residual radio-activity of inserting devices and radio-activity from extra-vasation in the patients, it seems to be more useful in clinical field.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.2
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• pp.107-117
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• 2004

If doubtlessly contributes much to agriculture and rural development. The roles can be summarized as; 1. to activate rural areas and to provide more comfortable and safe rural life with equivalent services to those in urban areas, facilitating distance education, tole-medicine, remote public services, remote entertainment etc. 2. To initiate new agricultural and rural business such as e-commerce, real estate business for satellite officies, rural tourism and virtual corporation of small-scale farms. 3. To support policy-making and evaluation on optimal farm production, disaster management, effective agro-environmental resource management etc., providing tools such as GIS. 4. To improve farm management and farming technologies by efficient farm management, risk management, effective information or knowledge transfer etc., realizing competitive and sustainable farming with safe products. 5. To provide systems and tools to secure food traceability and reliability that has been an emerging issue concerning farm products since serious contamination such as BSE and chicken flu was detected. 6. To take an important and key role for industrialization of farming or lam business enterprise, combining the above roles.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.2
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• pp.161-167
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• 2017

This experiment was conducted to comparison study on the productivity for certified varieties of import adaptability of silage corn in Pyeongchang area. Total eight varieties (Gangpyeongok, 31N27, 32P75, 32W86, P3156, P3394, DK 689 및 DK 729) were evaluated. The experimental design was 8 treatment of randomized block with three replications. Corn varieties were cultivated in experimental field of Pyeongchang campus, SNU from 1 May to 2 September, 2015 and plot size was $15m^2$. Plant height of 32W86 and ear height of Gwanpyeongok was the highest (p<0.05). Tasseling and silking date was 27 July-3 August and silking occurred after 1-3 day of tasseling. Average day to silking was 92 days and that of 31N27 variety was short (p<0.05). The varieties of DeKalbo Company (DK 689 and DK 729) required more times to silking. Average GDD (growth degree day) of eight varieties was $1,023^{\circ}C$ and P3352 was the lowest GDD. In the trials of resistance evaluation, P3394 was strong in disease, P3156 was the highest in insect. All varieties did not show the lodging and variety of DK 729 showed the highest stay green score (p<0.05). Average dry matter content was 30.77%, it showed higher trend in DM. 32W86 was the highest DM content among the varieties, but there was no significant difference among varieties (p>0.05). The weight per ear was the highest in 32W86 and the lowest in Gwanpyeongok. The ration of ear to whole plant was higher in 32W86 and P3394, but it was not found the significant difference (p>0.05). Average yield of fresh and DM was 59,017 and 13,476 kg/ha, respectively. DK 689 showed higher DM and TDN yield than others, but there was not significant difference (p>0.05). According to results, the difference of productivity was not found among certified variety of import adaptability of silage corn. The varieties Gwanpyeongok, 32W86 and 32P75 would be recommendable in Pyeongchang area for stable cultivation.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.247-254
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• 2011

The agronomic characteristics, nutritional contents, and insect response of the potato clones transformed with a glufosinate ammonium resistance gene were evaluated. Among the 4 transgenic potato clones, the Bar 3 clone was selected as a promising one for commercialization. The Bar 3 clone showed similar tuber yield capacity but higher herbicide resistance as compared with the non-transgenic potato cv. Dejima. The herbicide resistance of the Bar 3 clone was more than 5 times higher when tested with the herbicide concentration recommended by the producer. The major agronomic characteristics of the Bar 3 clone were not different from those of the non-transgenic Dejima. The annual variation in yields and agronomic characteristics showed similar tendency for 2 years from the third to fourth generation after transformation. The tubers of the Bar 3 clone also showed low occurrence in common scab and physiological disorders such as cracking and secondary growth. But the reasons for such results are yet to be studied. Also, it was considered that the Bar 3 clone have a potential of reducing not only common scab occurrence but also soil erosion during potato cultivation in field. The nutritional contents (mineral compound, vitamin C and amino acid) and response to Spodoptera exigua of the transgenic potato clones were not significantly different.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.118-124
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• 2003

For the rapid detection of various pathogenic microorganisms from food sample, various kinds of kits have been developed and commercially available in the markets. With the advantages of speed, accuracy and easiness, the market of these kits has gradually increased for the QC and QA field of food company as well as testing facilities or laboratories. In this study, the characteristics such as the detection limit and the sensitivity of immunochromatographic type of rapid detection kit (Donga Co, Korea, D-kit) for E. coli 0157:H7 developed by monoclonal antibody were examined and also the possibility of application of the kit to food samples was evaluated. The reference kits used for comparison study were Reveal E. coli 0157:H7 (Neogen Co., USA, R-kit) and VIP EHEC kit (Biocontrol Inc., USA, V-kit) occupying major market share. In the detection limit test with the E. coli 0157:H7 reference, both R-kit and D-kit showed a distinct positive reaction in $10^4$/ml and weak positive reaction in $10^3$/ml, whereas V-kit showed a same reaction in 105/ml. Also, it was identified that the culture treated with heat showed more sensitivity than no heat treated culture. The sensitivity test was conducted against 22 isolates of E. coli 0157:H7, 7 strains of non-O157:H7 verotoxin-producing E. coli, 40 strains of E. coli with different O and H antigen type, and 38 strains of non-E. coli Enterobacteriaceae, and all of the test strains except three were showed exactly three were showed exactly the same reaction against three kinds of the tested kits. All the three kinds of kits showed a positive reaction against E. coli O157:H19, E. coli O148:H18 and Salmonella galinarium. We suppose that there might be a similarity in serological property between these three strains and O157:H7. From the test results, it can be concluded that there is (was) no difference between the D-kit developed in this study and R-kit or V-kit based on the detection limit and sensitivity.