• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.407-415
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• 2019

The biological half-life of pesticides applied on crops is the key indicator for ensuring the safety of agricultural products. The biological half-life is affected by the several factors like growing conditions of the crop, climate, application method, and physicochemical properties of pesticides. In this study, the biological half-life was calculated and the degradation rates of six triazole fungicides sprayed on perilla leaves were evaluated. Moreover, the statistical analysis confirmed the correlation between the biological half-life and physicochemical properties of six triazole pesticides. The recoveries of the six pesticides were between 84.8-104.9%, which satisfied the residual pesticide analysis criteria. The biological half-life of six pesticides sprayed on perilla leaves, calculated using the first-order kinetics model, ranged between 6.4-15.1 days. When the biological half-life and the physicochemical properties were correlated using the principal component analysis: pKa and Log P, the biological half-life was found to be affected by PC1. The correlation coefficient between biological half-life and physicochemical properties (pKa), calculated by Spearman rank-order correlation, was R² = -0.928 (p <0.01). Biological half-life has been shown to correlate with pKa. In conclusion, it can be used as a database for the relationship between biological half-life and physicochemical properties and will contribute to ensure safe supply of agricultural products.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.393-404
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• 2007

The purpose of this study is to capture the essentials in survey and evaluation scheme which are able to assess the hazard of a rock slope systematically. Statistical analysis are performed on slope instability parameters related to failure of the rock slope. As the slope instability parameters, twelve survey items are considered such as tension crack, surface deformation, deformation of retaining structures, volume of existing failures, angles between strike of discontinuity and strike of cut slope face, angles between dip of discontinuity and dip of cut slope face, discontinuity condition, cut slope angle, rainfall or ground water level, excavation condition, drainage condition, reinforcement. A total of 233 road cut slopes located in Gyeongnam were considered. The stability of the road cut slopes were evaluated by estimating the slope instability index(SII) and corresponding stability rank. 126 rock slopes were selected to analyze statistical relation between SII and slope instability parameters. The multiple regression analysis was applied to derive statistical models which are able to predict the SII and corresponding slope stability rank. Also, its applicability was explored to predict the slope failures using the variables of slope instability parameters. The results obtained in this study clearly show that the methodology given in this paper have strong capabilities to evaluate the failures of the road cut slope effectively.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.529-538
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• 2018

The port industry is an important national industry which significantly affects Korea's imports and exports which are centered on economic structure. For instance, the Port of Busan, which handles 75% of domestic container freight volume, is expected to become increasingly critical for container liner routes. For this reason, there have been continued efforts to expand freight service to attract international freight volume. This study analyzes the structural characteristics of the port network connected to the Port of Busan by analyzing the pattern of the container liner route from 2012 to 2016 by using social network analysis. According to the Port of Busan's liner route network, the port with the highest degree of centrality, closeness centrality, and betweenness centrality was found to be the Port of Singapore. The comparison of Busan's annual container handling rank by countries and the port center network analysis of Port of Busan rank was found to be different. As a result, it was established that China's East Port, which occupies a high percentage of the volume of cargo handled by Port of Busan, is not a hub port of Busan when viewed on the Busan's container terminal liner network. In addition, even if the number of Port of Busan container liner service increases, it is estimated that the vessels to be added to the fleet will be limited to small to medium sized, or that Busan port has characteristic of a feeder port for the Port of Singapore, according to the network.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.1974-1984
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• 2021

Objective: This study aimed to compare the efficacy between no-touch (NT) radiofrequency ablation (RFA) and conventional RFA using twin internally cooled wet (TICW) electrodes in the bipolar mode for the treatment of small hepatocellular carcinomas (HCC). Materials and Methods: In this single-center, two-arm, parallel-group, prospective randomized controlled study, we performed a 1:1 random allocation of eligible patients with HCCs to receive NT-RFA or conventional RFA between October 2016 and September 2018. The primary endpoint was the cumulative local tumor progression (LTP) rate after RFA. Secondary endpoints included technical conversion rates of NT-RFA, intrahepatic distance recurrence, extrahepatic metastasis, technical parameters, technical efficacy, and rates of complications. Cumulative LTP rates were analyzed using Kaplan-Meier analysis and the Cox proportional hazard regression model. Considering conversion cases from NT-RFA to conventional RFA, intention-to-treat and as-treated analyses were performed. Results: Enrolled patients were randomly assigned to the NT-RFA group (37 patients with 38 HCCs) or the conventional RFA group (36 patients with 38 HCCs). Among the NT-RFA group patients, conversion to conventional RFA occurred in four patients (10.8%, 4/37). According to intention-to-treat analysis, both 1- and 3-year cumulative LTP rates were 5.6%, in the NT-RFA group, and they were 11.8% and 21.3%, respectively, in the conventional RFA group (p = 0.073, log-rank). In the as-treated analysis, LTP rates at 1 year and 3 years were 0% and 0%, respectively, in the NT-RFA group sand 15.6% and 24.5%, respectively, in the conventional RFA group (p = 0.004, log-rank). In as-treated analysis using multivariable Cox regression analysis, RFA type was the only significant predictive factor for LTP (hazard ratio = 0.061 with conventional RFA as the reference, 95% confidence interval = 0.000-0.497; p = 0.004). There were no significant differences in the procedure characteristics between the two groups. No procedure-related deaths or major complications were observed. Conclusion: NT-RFA using TICW electrodes in bipolar mode demonstrated significantly lower cumulative LTP rates than conventional RFA for small HCCs, which warrants a larger study for further confirmation.

• Toxicological Research
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• v.34 no.4
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• pp.303-310
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• 2018

The methods of applied genetic toxicology are changing from qualitative hazard identification to quantitative risk assessment. Recently, quantitative analysis with point of departure (PoD) metrics and benchmark dose (BMD) modeling have been applied to in vitro genotoxicity data. Two software packages are commonly used for BMD analysis. In previous studies, we performed quantitative dose-response analysis by using the PROAST software to quantitatively evaluate the mutagenicity of four piperidine nitroxides with various substituent groups on the 4-position of the piperidine ring and six cigarette whole smoke solutions (WSSs) prepared by bubbling machine-generated whole smoke. In the present study, we reanalyzed the obtained genotoxicity data by using the EPA's BMD software (BMDS) to evaluate the inter-platform quantitative agreement of the estimates of genotoxic potency. We calculated the BMDs for 10%, 50%, and 100% (i.e., a two-fold increase), and 200% increases over the concurrent vehicle controls to achieve better discrimination of the dose-responses, along with their BMDLs (the lower 95% confidence interval of the BMD) and BMDUs (the upper 95% confidence interval of the BMD). The BMD values and rankings estimated in this study by using the EPA's BMDS were reasonably similar to those calculated in our previous studies by using PROAST. These results indicated that both software packages were suitable for dose-response analysis using the mouse lymphoma assay and that the BMD modeling results from these software packages produced comparable rank orders of the mutagenic potency.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.63-73
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• 1993

For a systematic approach to rural settlement planning, socio-economic and land use potentialities were analysed in 10 villages("Ri", the lowest-order administrative unit in Korea)of Izuk-myun, Anseong-gun, Kyeonggi province, the model area in this study. Socio-economic potentialities, sub-grouped into rural and urban related ones, were analysed by the principal component analysis technique, while land use potentialities by the land suitability system of which the physical analysis is based on geographical information system. The principal component of rurality is strongly related with 5 key variables such as annual increasing rate of farm households, ratio of over 1ha-households, ratio of full-time farmers, ratio of animal rearing households and the principal component of urbanity with 6 key ones such as population density, number of schools, number of shops and servicing facilities, number of daily bus routes, number of non-farm households, percentage of area of housing sites. The analysis procedure of land suitability using the geographical information system were generalized and the results of analysis on village sites and paddy and upland fields were presented. The whole land use planning was presented by the criteria of the land suitability rank and the priority order of land use. land use.

• KIEAE Journal
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• v.14 no.4
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• pp.103-109
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• 2014

The purpose of this study was to evaluate the usability and satisfaction of space to which positive elements in Leed-Certified Office Building are applied. The study was conducted using the three-step approach. The first step was to understand the building and identify the issues which included the analysis of floor plans, documentations, and the interview with designers and facility managers. The second step was FGI(Focus Group Interviews), which were conducted with mixed employees of rank and location of workplace. Finally, a web-based questionnaire survey was conducted on the 319 executives and employees. Methods of analysis used were quantitative analysis of questionnaire, qualitative analysis of open ended free-answer, and FGI in the second step. Satisfaction, preference, and comfort level were studied using cross tab, co-relation, ANOVA for quantitative analysis. The results of this study are as follows: First, lobby and atrium are representative elements that are functioning positively and it is recognized as sustainable spaces being utilized by users. Second, there are several dead spaces like green shaft, roof garden and sunken space although they can contribute to Leed-certification. Third, there are some problematic spaces such as the O.A. room and the urinals even though they contribute to the Leed-certification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.304-309
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• 2015

Applicable range of Photoplethysmography (PPG) becomes wider as a non-invasive physiological measurement technique. However, PPG waveform is easy to be distorted by ambient light or vascular variation from temperature changes. Especially, irregular variation of PPG waveform caused by ambient temperature not only severely distorts the PPG, but also leads miss interpretation in clinical applications. Therefore, the investigation of between temperature and PPG waveform is quite important in using PPG. The purpose of this research is to quantify the PPG waveform characteristic and to investigate the waveform variation following the temperature change on measuring site. To quantify the fluctuation of PPG waveform, we use two techniques; detrended fluctuation analysis (DFA) and AC/DC analysis of PPG. We record PPG under temperature stress, which applied by medical use heat pack ($40^{\circ}C$) and ice pack ($0^{\circ}C$). Ten participants were applied to the experiment, and the result was evaluated to approve the temperature effect with statistical method, Wilcoxon signed rank test. The result shows that the AC component (p<0.05) and perfusion index DFS scale exponent (p<0.01) of PPG have the significance to temperature stress except for a DC component of PPG.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.2
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• pp.129-137
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• 2016

A colonoscopy is important because it detects the presence of polyps in the colon that can lead to colon cancer. How often one needs to repeat a colonoscopy may depend on various factors. The main purpose of this study is to determine personalized surveillance interval of colonoscopy based on characteristics of patients including their clinical information. The clustering analysis using a partitioning around medoids algorithm was conducted on 625 patients who had a medical examination at Korea University Anam Hospital and found several subgroups of patients. For each cluster, we then performed survival analysis that provides the probability of having polyps according to the number of days until next visit. The results of survival analysis indicated that different survival distributions exist among different patients' groups. We believe that the procedure proposed in this study can provide the patients with personalized medical information about how often they need to repeat a colonoscopy.

• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.690-703
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• 2010

Sampling based uncertainty analysis was carried out to quantify uncertainty in predictions of best estimate code RELAP5/MOD3.2 for a thermal hydraulic test (10% hot leg break LOCA) performed in the Large Scale Test Facility (LSTF) as a part of an IAEA coordinated research project. The nodalisation of the test facility was qualified for both steady state and transient level by systematically applying the procedures led by uncertainty methodology based on accuracy extrapolation (UMAE); uncertainty analysis was carried out using the Latin hypercube sampling (LHS) method to evaluate uncertainty for ten input parameters. Sixteen output parameters were selected for uncertainty evaluation and uncertainty band between $5^{th}$ and $95^{th}$ percentile of the output parameters were evaluated. It was observed that the uncertainty band for the primary pressure during two phase blowdown is larger than that of the remaining period. Similarly, a larger uncertainty band is observed relating to accumulator injection flow during reflood phase. Importance analysis was also carried out and standard rank regression coefficients were computed to quantify the effect of each individual input parameter on output parameters. It was observed that the break discharge coefficient is the most important uncertain parameter relating to the prediction of all the primary side parameters and that the steam generator (SG) relief pressure setting is the most important parameter in predicting the SG secondary pressure.