• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.712-721
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• 2012

In this paper, we propose an Enhanced cross-layer Geographic Forwarding (EGF) protocol for wireless sensor networks (WSNs). EGF uses an optimal back-off time to make the packet forwarding decisions using only source and destination's location information and energy cost without information about neighbor nodes' location or the number of one hop neighbor nodes. EGF is also a cross-layer protocol by combining efficient asynchronous MAC and geographic routing protocol. The proposed protocol can find optimal next hop location quickly without broadcasting node's location update and with minimizing overhead. In our performance evaluation, EGF has better performance in terms of packet success ratio, energy efficiency and end-to-end delay in wireless sensor networks.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.491-502
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• 1995

In accurate prediction of cross-flow based on detailed knowledge of the velocity field in subchannels of a nuclear fuel assembly is of importance in nuclear fuel performance analysis. In this study, the low-Reynolds number k-$\varepsilon$ turbulence model has been adopted in too adjacent subchannels with cross-flow. The secondary flow is accurately estimated by the anisotropic algebraic Reynolds stress model. This model was numerically calculated by the finite element method and has been verified successfully through comparison with existing experimental data. Finally, with the numerical analysis of the velocity Held in such subchannel domain, an analytical correlation of the lateral loss coefficient is obtained to predict the cross-flow rate in subchannel analysis codes. The correlation is expressed as a function of the ratio of the lateral How velocity to the donor subchannel axial velocity, recipient channel Reynolds number and pitch-to-diameter.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.143-148
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• 2024

Traffic congestion has caused issues in various forms such as the environment and economy. Recently, an intelligent transport system (ITS) using artificial intelligence (AI) has been focused so as to alleviate the traffic congestion problem. In this paper, we propose a reinforcement learning-based traffic signal control algorithm that can smooth the flow of traffic while reducing discomfort levels of drivers and pedestrians. By applying the proposed algorithm, it was confirmed that the discomfort levels of drivers and pedestrians can be significantly reduced compared to the existing fixed signal control system, and that the performance gap increases as the number of roads at the intersection increases.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.67-76
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• 2014

The purpose of this study was to examine the rate of intention and registration of organ donation and to find their associated factors among some medical and nursing students. The study subjects were 629 students who majored in the medicine and nursing in medical school. The data were collected from self-administerd questionnaire composed of intention and registration of organ donation and scales of knowledge and attitude toward organ donation. As a result, the rates of intention and registration of organ donation were 72.1% and 12.5%, respectively. The associated factors with the intention of organ donation were sex, judging the brain death as a death, attitude for organ donation. The associated factors with the registration of organ donation were major, knowledge scores and attitude scores of organ donation.

• Journal of Korean Society of Transportation
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• v.23 no.4 s.82
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• pp.47-55
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• 2005

In recent years, the rapid growth of vehicles have increased traffic crashes. Since they can cause the economic losses and have put the life qualify in danger, there should be numerous efforts to reduce traffic crashes. To reduce traffic crashes, this research seeks to improve the safety of intersections by analysing causations of injury severity with Ordered Probability Model. This research applied the Ordered Probit Model, which assumes that ${\epsilon}_i$(random error) is normally distributed, for model calibration and used $p^2$ (likelihood ratio) and $x^2$ (Chi-square) for model selection. The results show that minor road traffic, heavy vehicle rates, major and minor right-turn rates, presence of lightings, speed limits, instructive line for left-turn traffic are significant factors affecting crash severities at signalized intersections.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.326-336
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• 2014

The purpose of this study was to assess the association between habitual snoring and metabolic syndrome in the Korean population and to evaluate it's possible gender variations. The study subjects were 2,007 volunteers aged 40-69 years who participated in regular health check-ups(male:434, female:1,573) from May 2012 to December 2012. Standard interviews, anthropometrics and biochemical studies were conducted. Habitual snoring was defined as snoring more than 4 days per week. The prevalence of metabolic syndrome in our sampling pool was 17.4% (male: 20.7%, female: 16.5%), and this increased with age. After adjusting for age, smoke and alcohol consumption, sleep duration, regular exercise, the odds ratio of metabolic syndrome and it's components were increased significantly by habitual snoring. HDL-cholesterol, blood sugar, waist size were significantly higher in women, but not significantly higher in men.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.149-157
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• 2018

This study was conducted using the National Health and Nutrition Survey data for 2010-2014 to investigate the relationship between pregnancy-related health factors and periodontitis in adult women. Dependent variable was periodontitis, and independent variables, pregnancy-related health factors(duration of lactation and number of pregnancies) were analyzed. Socioeconomic variables and health-related behaviors were corrected by confounding variables. The number of pregnancies and periodontitis were highly correlated after adjusting for various confounding factors [odds ratio for women with 2-3 pregnancies: 2.66 (95% confidence interval(CI): 1.56-4.54); The odds ratio for women with four or more pregnancies 3.02 (95% CI: 1.70-5.36). In conclusion, periodontitis is closely related to the number of pregnancies and this will be used as basic data for development of oral health education programs for women and pregnant women.

• Journal of Preventive Medicine and Public Health
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• v.22 no.1 s.25
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• pp.65-70
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• 1989

To examine the association between serum HBeAg status and tuberculosis infection, we reviewed medical records of 579 inpatients who had serum HBeAg test with RIA method at the Department of Nuclear Medicine of Kyungpook University Hospital from January 1, 1985 to December 31, 1987. HBeAg positive patients had lower tuberculosis infection rate(5.0%) than that of HBeAg negative patients(9.8%) and the odds ratio of HBeAg associated with tuberculosis was 0.48(95% C.I.:0.22-1.08). Similar relationship was found in the patients of hepatobiliary diseases; tuberculosis infection rate was 4.4% in HBeAg positive patients, 8.1% in HBeAg negative patients, and the odds ratio was 0.52(95% C.I.:0.17-1.35). Although the association did not reach the statistical significance level of 0.05, the negative association was consistent with other study done on Southeast Asian population of Philadelphia. A cohort study in general population is warranted to confirm above findings because of the limitations on hopital-based data.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.9
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• pp.777-781
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• 2001

This paper presents an image contrast enhancement technique for improving the low contrast images using the improved IAFC(Integrated Adaptive Fuzzy Clustering) model. The low pictorial information of a low contrast image is due to the vagueness or fuzziness of the multivalued levels of brightness rather than randomness. Fuzzy image processing has three main stages, namely, image fuzzification, modification of membership values, and image defuzzification. Using a new model of automatic crossover point selection, optimal crossover point is selected automatically. The problem of crossover point selection can be considered as the two-category classification problem. The improved IAFC model is used to classify the image into two classes. The proposed method is applied to several experimental images with 256 gray levels and the results are compared with those of the histogram equalization technique. We utilized the index of fuzziness as a measure of image quality. The results show that the proposed method is better than the histogram equalization technique.

• Journal of the Korea Convergence Society
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• v.10 no.1
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• pp.239-244
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• 2019

The aim of this study was to evaluate the association between Lipid profiles and periodontal diseases in Korea adults. The date from the 2013, 2014 Korean National Health and Nutrition Survey were used, and 8,854 subjects over 30 years were included in the analysis. periodontal disease was assessed using the Community periodontal Index. Study participants with HDL between ${\leq}40mg/dL$(high) were 1.39 times(95% CI=1.16 to 1.66) as likely to have periodontal disease as those with normal levels and those with Triglyceride ${\geq}200mg/dL$(high) were 1.14 times(95% CI=1.02 to 1.27) as likely to have periodontal disease as those with normal levels. positive significant association was observed between serum lipid profiles and periodontal disease; however, further studies need to be conducted to understand the actual relationship between STC levels and periodontitis and to establish causality and directional association.