• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.1
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• pp.15-29
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• 2010

Spalling is a kind of instability phenomenon of surrounding rock around underground openings subjected to high in-situ stress according to the development of extension fractures. Three kinds of spalling criteria have been presented so far; however, all spalling criteria have the range of values so that the fuzziness and vagueness of spalling criterion cannot be avoided. In this study, a new fuzzy probability model is proposed to predict the probability of spalling in a systematic way by using fuzzy probability theory. Many of the underground opening projects worldwide are evaluated with the proposed method. Prediction results expressed as the spalling probability agree well with the in-situ observations. In particular, a new fuzzy probability model considering all three evaluation indices of spalling by adopting weighting factors based on relative reliability among three evaluation indices is able to resolve erroneous prediction of spalling by choosing only one prediction method. Moreover, the more reasonable value of spalling probability could have been obtained by adopting the modified damage index to the newly proposed fuzzy probability model.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.509-517
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• 2023

This study analyzed imaging conditions and exposure index through clinical information collection and dose calculation programs in coronary angiography examinations. Through this, we aim to analyze the effective dose according to examination conditions and provide basic data for dose optimization. In this study, ALARA(As Low As Reasonably Achievable)-F(Fluoroscopy), a program for evaluating the radiation dose of patients and the collected clinical data, was used. First, analysis of imaging conditions and exposure index was performed based on the data of the dose report generated after coronary angiography. Second, after evaluating organ dose according to 9 imaging directions during coronary angiography, with the LAO fixed at 30°, dose evaluation was performed according to tube voltage, tube current, number of frames, focus-skin distance, and field size. Third, the effective dose for each organ was calculated according to the tissue weighting factors presented in ICRP(International Commission on Radiological Protection) recommendations. As a result, the average sum of air kerma during coronary angiography was evaluated as 234.0±112.1 mGy, the dose-area product was 25.9±13.0 Gy·cm², and the total fluoroscopy time was 2.5±2.0 min. Also, the organ dose tended to increase as the tube voltage, milliampere-second, number of frames, and irradiation range increased, whereas the organ dose decreased as the FSD increased. Therefore, medical radiation exposure to patients can be reduced by selecting the optimal tube voltage and field size during coronary angiography, maximizing the focal-skin distance, using the lowest tube current possible, and reducing the number of frames.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4570-4575
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• 2023

Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

• Journal of Soil and Groundwater Environment
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• v.13 no.4
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• pp.40-53
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• 2008

Groundwater pollution prediction methods have been developed to plan the sustainable groundwater usage and protection from potential pollution in many countries. DRASTIC established by US EPA is the most widely used groundwater vulnerability mapping method. However, the DRASTIC showed limitation in predicting the groundwater contamination because the DRASTIC method is designed to embrace only hydrogeologic factors. Therefore, in this study, three different methods were applied to improve a groundwater pollution prediction method: US EPA DRASTIC, Modified-DRASTIC suggested by Panagopoulos et al. (2006), and LSDG (Land use, Soil drainage, Depth to water, Geology) proposed by Rupert (1999). The Modified-DRASTIC is the modified version of the DRASTIC in terms of the rating scales and the weighting coefficients. The rating scales of each factor were calculated by the statistical comparison of nitrate concentrations in each class using the Wilcoxon rank-sum test; while the weighting coefficients were modified by the statistical correlation of each parameter to nitrate concentrations using the Spearman's rho test. The LSDG is a simple rating method using four factors such as Land use, Soil drainage, Depth to water, and Geology. Classes in each factor are compared by the Wilcoxon rank-sum test which gives a different rating to each class if the nitrate concentration in the class is significantly different. A database of nitrate concentrations in groundwaters from 149 wells was built in Keumsan area. Application of three different methods for assessing the groundwater pollution potential resulted that the prediction which was represented by a correlation (r) between each index and nitrate was improved from the EPA DRASTIC (r = 0.058) to the modified rating (r = 0.245), to the modified rating and weights (r = 0.400), and to the LSDG (r = 0.415), respectively. The LSDG seemed appropriate to predict the groundwater pollution in that it contained land use as a factor of the groundwater pollution sources and the rating of each class was defined by a real pollution nitrate concentration.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.123-138
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• 2018

To sustainably monitor air pollution in Seoul, the number of Air Pollution Monitoring Station has been gradually increased by Korea's Ministry of Environment. Although particulate matters(PM), one of the pollutants measured at the stations, have an significant influence on human body, the concentration of PM in Korea came in second among 35 OECD member countries. In this study, using the data of PM concentration from the stations, distribution maps of PM10 and PM2.5 concentrations over Seoul were generated, and spatial factors potentially related to PM distribution were investigated. Based on a circumscribed hexagon about a circle in radius of 500 meters created as a basic unit, Seoul was sectionalized and PM concentration map was generated using the interpolation technique of 'inverse distance weighting'. The distributions of PM concentrations were investigated with commuting time by administrative district and the outcome was related with land-use type and volume of traffic. Results from this analysis indicated distribution pattern of PM10 concentration was different from that of PM2.5 by administrative district and time. The distribution of PM concentration was strongly related to not only the size of business and trafficked areas among the land-use type, but also the existence of urban green. Further analysis of the relationship between the PM concentration and detailed land-use and urban green maps can be helpful to identify spatial factors which have an impact on the PM concentration on the regional scale.

• Korea Journal of Hospital Management
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• v.5 no.1
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• pp.176-199
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• 2000

This study is to identify factors affecting public relations(PR) activities through newspapers among hospitals. 53 acute hospitals with more than fill beds were surveyed by telephone interview, and hospital-related articles on 4 major daily newspapers were searched in KINDS(Korea Intergrated Newspapers Database System). Hospitals' PR scores were evaluated by weighting the directoin and the number of hospitals mentioned in an articles. The scores were analysed as the outcome of PR activities by some general characteristics. The mean of PR score was 4.64, most hospitals(22, 41.5%) fell on the group scored more than 0 and less than 5. Hospitals with score under zero were 7(13.2%) and the hospitals scored over 20 point were 3(5.8%). The number of beds and area, two general characteristics of hospitals, had decisive effect on PR activities. Analysis showed hospitals over 1000 beds scored 17.06 point and this group accounted for the highest. Hospitals from 600 to 799 beds scored 2.86, with 800 to 999beds scored 1.93 and with 500 to 599 beds scored 0.59. Along with area, hospitals in Seoul scored 11.50 point, in Kyong-Ki and Incheon scored 1.50 and in the other areas scored -0.23 point. Department for PR and the number of workers in PR activities made hospitals active in PR. Hospitals with PR department scored 7.05 point, without PR department scored 0.98. Hospitals with workers who is whole responsibility over 5 scored 13.67, from 3 to 4 scored 6.54, from 1 to 2 scored 1.02, and the hospitals without workers who is whole responsibility scored 0.53. Among the characteristics related with PR activities, the assignment of a report in individual hospital had significant effect on the outcome of PR. Hospitals with assigned reporters scored 8.31 point, without them scored 1.89. Finally, the factors affecting PR score were identified by multiple regression analysis. The number of beds and the area(Seoul) were significantly associated with the score in positive direction.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6935-6940
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• 2013

Background: This study aimed to develop a prognostic model in patients with early-stage cervical squamous cell carcinoma based on clinicopathological features, including invasive margin characteristics. Materials and Methods: Clinicopathological features and outcomes of 190 patients with FIGO stage IB-IIA cervical squamous cell carcinoma treated by surgery were collected and analyzed for factors associated with tumor recurrence. In addition to well-recognized pathological risk factors, the pathological characteristics of invasive margin (type of invasive pattern and degree of stromal desmoplasia and peritumoral inflammatory reaction) were also included in the analysis. Multiple scoring models were made by matching different clinicopathological variables and/or different weighting of the score for each variable. The model with the best performance in the prediction of recurrence and decreased survival was selected. Results: The model with the best performance was composed of a combined score of invasive pattern, lymphovascular space invasion (LVSI), and degree of inflammatory reaction and stromal desmoplasia (total score =10). Compared to those with score ${\leq}8$, the patients with score 9-10 had a significantly higher recurrence rate in the overall group (p<0.001) and the subgroup without adjuvant therapy (p<0.001), while the significance was marginal in the subgroup with adjuvant therapy (p=0.069). In addition, the patients with score 9-10 had a higher rate of tumor recurrence at distant sites (p=0.007). The disease-free survival was significantly lower in the patients with score 9-10 than those with score ${\leq}8$ among the overall patients (p<0.001), in the subgroup without adjuvant therapy (p<0.001), and the subgroup with adjuvant therapy (p=0.047). Conclusions: In this study, a prognostic model based on a combination of pathological characteristics of invasive margin and LVSI proved to be predictive of tumor recurrence and decreased disease-free survival in patients with early-stage cervical squamous cell carcinoma.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.1-9
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• 2010

Technology-Based Effluent Limitations (TBELs) is a permit limits for a pollutant that is based on the capability of a treatment technology to reduce the pollutant to a certain concentration. Widely practiced for regulations of industrial wastewater in US, TBELs has been accepted as an effective means that can achieve balanced goals between complete elimination of pollutants discharge and economic feasibility for industries. The review of TBELs application in US and the applicability of TBELs to the domestic industry categories was given in three papers. In the first paper, the development and practices of TBELs in US were reviewed including case studies. The developments of TBELs in US in the four major categories, the metal products & machinery, the petroleum refining, the porcelain enameling and the meat & poultry products were reviewed. The applicability of TBELs to the domestic industrial categories was also assessed. In the second paper, the pollution loads analysis for domestic industrial wastewater was conducted based on risk assessment indicator using Toxic Weighting Factors (TWFs). This is an essential part to determine the priority of TBELs application for the domestic industrial categories. In the last paper, the application of TBELs to the domestic industries was demonstrated through a case-study for the pulp/paper/paperboard category. Direct application of TBELs of US into the Korean regulation system may not be desirable because the specific goals and the environment for the regulations for the two countries may not be identical. For example, unlike US, Korea does not adopt the individual permit system for pollution sources. However, among the unproductive and exhaustive controversies over the uniform regulations regardless of the industrial categories in Korea, the introduction of the principles of TBELs are inevitable and more extensive study for applications of TBELs optimized for Korean regulation system will be necessary.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.287-297
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• 2016

This study aims to identify the relationship between climatic factors and stand mean Diameter at Breast Height (DBH) for two major tree species; Pinus densiflora and Quercus mongolica in Andong-dam basin. Forest variables such as age, diameter distribution and number of trees per hectare from the $5^{th}$ and $6^{th}$ National Forest Inventory data were used to develop a DBH estimation model. Climate data were collected from six meteorological observatory station and twelve Automatic Weather System provided by Korea Meteorological Administration to produce interpolated daily average temperature map with Inverse Distance Weighting (IDW) method. Andong-dam basin reflects rugged mountainous terrain, so temperature were adjusted by lapse rate based correction. As a result, predictions of model were consistent with the previous studies; that the rising temperature is negatively related to the growth of Pinus densiflora whereas opposing trend is observed for Quercus mongolica.

• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.119-142
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• 2014

This study aims to evaluate the factors which affect the competitiveness of Gwangyang port, and to suggest strategies for the enhancement of its competitiveness by priority. This study inquires both 5 key rating factors: port location, port operations management, port costs, port facilities, and hinterland conditions and the priority of 14 detailed assessments through AHP method. First, the importances of main evaluation items for port competitiveness are analysed in the following orders: port location, port facilities, port costs, port operations, hinterland conditions. Second, the comprehensive importances based on the detailed evaluation properties complex weighting are identified in the following orders: connectivity with hinterland, accessibility of international harbor, incentives, the area of terminal, expertise and skills of port operations personnel, container throughput, and scale berths. Third, the strategies referring to the port location like centrality, transit, and merit on use should be actively conducted for the promotions of Gwangyang port's competitiveness, according to its international port competitiveness analysis. This study will provide both academic and policy implications with its related scholars, government, and research institutions. In addition, this will be contributed to formulating a basic theory for port competitiveness evaluation and providing a basic framework of evaluation analysis.