• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.63-70
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• 1993

A simplified safety assessment is carried out on rock-cavern type disposal of LLW using the analytical repository source term (REPS) model. For reliable prediction of the leach rates for various radionuclides, degradation of concrete structures, corrosion rate of waste container, degree of corrosion on the container surface, and the characteristics of radionuclides are considered in the REPS model. The results of preliminary assessment show that Cs-137, Ni-63, and Sr-90 are dominant. For the parametric uncertainty and sensitivity analysis, Latin hypercube sampling technique and rank correlation technique are applied. The results of the potential public health impacts show that radiological dose to intruder in the worst case scenario will be negligible and that more attention should be given to near-field performance.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.274-278
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• 2021

Road structures play an important role in collisions involving vehicles and wildlife. Our study aimed to determine the effect of various types of road structures on the risk associated with roadkill. We surveyed 50 previously identified roadkill hotspots, ranked from one to five according to roadkill density. We collected nine types of road structure data on each hotspot road section. Structures with similar characteristics were grouped together, resulting in five categories, namely, median barrier, high edge barrier, low edge barrier, speed, and visibility. We examined the existence of each road structure category at each hotspot rank. The cumulative link model showed that the absence of bottom blocked median barrier increased the roadkill hotspot rank. Our study concluded that a visual obstacle in the middle of roads by the median barrier decreases wildlife road crossing attempts and roadkill risk. We suggest that future roadkill mitigation plans should be established considering these characteristics.

• Journal of Preventive Medicine and Public Health
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• v.43 no.2
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• pp.174-184
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• 2010

Objectives: This study shows the issues that should be considered when applying standardized rates using Community Health Survey(CHS) data. Methods: We analyzed 2008 CHS data. In order to obtain the reliability of standardized rates, we calculated z-score and rank correlation coefficients between direct standardized rate and indirect standardized rate for 31 major indices. Especially, we assessed the change of correlations according to population composition (age and sex), and characteristics of the index. We used Mantel-Haenszel chi-square to quantify the difference of population composition. Results: Among 31 major indices, 29 indices' z-score and rank correlation coefficients were over 0.9. However, regions with larger differences in population composition showed lower reliability. Low reliability was also observed for the indices specific to subgroups with small denominator such as 'permanent lesion from stroke', and the index with large regional variations in age-related differences such as 'obtaining health examinations'. Conclusions: Standardized rates may have low reliability, if comparison is made between areas with extremely large differences in population composition, or for indicies with large regional variations in age-related differences. Therefore, the special features of standardized rates should be considered when health state are compared among areas.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.443-450
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• 2008

Efficient use of low rank coals (LRC) have been investigated as a method to cope with recent high oil price. Among the coals used in industry, lignite and sub-bituminous coals are belong to the LRC, and have abundant deposit and are distributed worldwide, but high moisture contents and self ignition properties inhibits their utilization. In this paper, chemical coal cleaning to produce ash-free coal from LRC has been investigated. Two technologies, that is, UCC(Ultra Clean Coal) process removing ash from coal and Hyper Coal process extracting combustibles from coal were compared with. UCC process has merits of simple and reliable when it compared with Hyper Coal process, but the remaining ash contents werehigher than Hyper Coal. Hyper Coal has ash contents under the 200ppm when raw coal is treated with appropriate solvent and ion exchange materials to remove alkali materials in extracted solution. The ash-free coal which is similar grade with oil can be used as alternate oil in the industry, and also used as a high grade fuel for IGCC, IGFC and other advanced combustion technology.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.825-828
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• 2013

Objective: The objective of this study was to determine the five-year survival among patients with cervical cancer treated in Hospital Universiti Sains Malaysia. Methods: One hundred and twenty cervical cancer patients diagnosed between $1^{st}$ July 1995 and $30^{th}$ June 2007 were identified. Data were obtained from medical records. The survival probability was determined using the Kaplan-Meier method and the log-rank test was applied to compare the survival distribution between groups. Results: The overall five-year survival was 39.7% [95%CI (Confidence Interval): 30.7, 51.3] with a median survival time of 40.8 (95%CI: 34.0, 62.0) months. The log-rank test showed that there were survival differences between the groups for the following variables: stage at diagnosis (p=0.005); and primary treatment (p=0.0242). Patients who were diagnosed at the latest stage (III-IV) were found to have the lowest survival, 18.4% (95%CI: 6.75, 50.1), compared to stage I and II where the five-year survival was 54.7% (95%CI: 38.7, 77.2) and 40.8% (95%CI: 27.7, 60.3), respectively. The five-year survival was higher in patients who received surgery [52.6% (95%CI: 37.5, 73.6)] as a primary treatment compared to the non-surgical group [33.3% (95%CI: 22.9, 48.4)]. Conclusion: The five-year survival of cervical cancer patients in this study was low. The survival of those diagnosed at an advanced stage was low compared to early stages. In addition, those who underwent surgery had higher survival than those who had no surgery for primary treatment.

• Nutrition Research and Practice
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• v.6 no.4
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• pp.349-356
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• 2012

Several studies have been conducted on dietary patterns based on carbohydrate nutrition in Asian populations. We examined the cross-sectional associations in dietary patterns based on carbohydrate nutrition, including the glycemic index (GI) with dyslipidemia and diabetes among the Korean adult population. We analyzed 9,725 subjects (3,795 men and 5,930 women, ${\geq}$ 20 years) from the Fourth Korea National Health and Nutrition Examination Survey. Dietary information was collected using single 24-hour recall. Reduced rank regression was used to derive dietary patterns from 22 food groups as predictor variables and four dietary factors related to the quantity and quality of carbohydrates as response variables. Two dietary patterns were identified: 1) the balanced pattern was characterized by high intake of various kinds of foods including white rice, and 2) the rice-oriented pattern was characterized by a high intake of white rice but low intake of vegetables, fruits, meat, and dairy products. Both patterns had considerable amounts of total carbohydrate, but GI values differed. The rice-oriented pattern was positively associated with hypertriglyceridemia in men and low high density lipoprotein-cholesterol in both men and women. The balanced pattern had no overall significant association with the prevalence of dyslipidemia or diabetes, however, men with energy intake above the median showed a reduced prevalence of diabetes across quintiles of balanced pattern scores. The results show that dietary patterns based on carbohydrate nutrition are associated with prevalence of dyslipidemia and diabetes in the Korean adult population.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.219-225
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• 2010

Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.604-611
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• 2017

In wireless sensor networks, an energy efficient operation is important since the energy of the sensors is limited. This paper proposes an energy efficient method that reduces a packet generation with Matrix Completion method where sensor value matrix has low-rank and decreases a collision rate and an overhead by transmitting only sensor ID to a time slot corresponding to the sensor value. Computer simulations demonstrates that the proposed method shows 17% of transmission failure and 73% of the packet generation compared to a conventional CSMA/CS. Delay time of transmitting information of the proposed method exhibits 22% of the CSMA/CA and the MSE error after reconstructing sensor values by Singular Value Thresholding(SVT) in Fusion Center is 87% of the CSMA/CA.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.145-155
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• 2015

Noise reduction has been actively studied in the digital image processing and recently, block-based denoising algorithms are widely used. In particular, a low rank approximation employing WNNM(Weighted Nuclear Norm Minimization) and block-based approaches demonstrated the potential for effective noise reduction. However, the algorithm based on low rank a approximation generates the artifacts in the image restoration step. In this paper, we analyzes the image content using the STFT(Short Time Fourier Transform) and proposes an effective method of minimizing the artifacts generated from the conventional algorithm. To evaluate the performance of the proposed scheme, we use the test images containing a wide range of noise levels and compare the results with the state-of-art algorithms.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.44-50
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• 2024

This study analyzed the effect of flight stress on job satisfaction and safety culture on 193 domestic civil airline pilots. As a result of the analysis, flight stress had a negative effect on job satisfaction, and pilots with low job satisfaction had a low awareness of safety culture. In particular, there was a difference in the effect of flight stress on job satisfaction and safety culture according to the airlines and rank of pilots. This suggests the necessity of developing customized stress management programs for each airline and pilot position. The study emphasizes the importance of managing pilots' stress and improving job satisfaction to reinforce the safety culture of the aviation industry. In addition, airlines should develop strategies to strengthen safety culture by reducing pilot stress and increasing job satisfaction. The result of this study is to be used as useful basic data for finding ways to manage pilots' stress and strengthen safety culture in the aviation industry.