• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.41.2-41.2
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• 2018

EL CVn-type eclipsing binaries are composed of a massive A-type main-sequence primary star and a hotter B-type secondary one. These are worthy of particular attention because the secondary stars are rare objects to be extremely low-mass white dwarf precursors (ELM proto-WD) with the mass of ${\leq}0.2M_{\odot}$, evolving to higher effective temperatures and higher surface gravities. A few of them were discovered to show multi-periodic pulsations in one or both components. We monitored one of these rare and interesting objects, J0247-25 (=1SWASP J024743.37-251549.2), at two KMTNet sites of SAAO in South Africa and SSO in Australia. The observations were performed with the KMTNet 1.6m telescopes and pre-science 4K CCD cameras during the system test run from July to November 2014. Using the photometric data obtained for a total of 23 nights, we constructed well-defined eclipsing light curves in B/V-bands and derived absolute parameters (mass and radius, etc.) of each binary component. After subtracting model eclipsing curves from the data, we detected seven frequencies with 33~53 cycles per day (c/d) and identified them to be Delta Sct-type pulsations originated from the A-type primary component. Five frequencies were turned out to be excited by rotational splitting of non-radial pressure modes, enabled us to investigate rotational properties. We could not detect any frequency higher than 100 c/d, implying that pulsation amplitudes of the proto-WD secondary decrease greatly.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.193-198
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• 2016

For environmental monitoring and risk identification of industrial plants, several monitoring systems using Wireless Sensor Networks (WSNs) have been developed. In this paper, we propose a dynamic duty cycle adjustment mechanism for reduced latency in industrial plants. The proposed method adjusts the duty cycle among predefined risk groups depending on the urgency of sensed data values. To demonstrate its efficacy, we analyze the expected transmission latency model and then discuss the characteristics in detail. We show that the proposed dynamic duty cycle mechanism is a more effective than a periodic mechanism by analyzing the expected latency of them in industrial plants where there are various types of sensory data with different levels of reliability.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.197-200
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• 2016

On an international scale, the burden of cancer in absolute numbers continues to increase, mainly due to aging of population in many countries, the overall growth of the world population, changing lifestyle with increasing cancer-causing behavior, like cigarette smoking, changing dietary habits and sedentary life. Cancer is the second-leading cause of death and disability in the world, after only heart disease. Recently, increasing incidence and mortality of cancer have also become evident in the developing world. In Iraq and particularly in Basrah in the southern part of the country, the burden has definitely increased and deserves extensive research. The present paper is part of an extensive household survey carried out in Basrah in 2013. Among the objectives was to validate official cancer registration in the governorate. The cross-sectional survey had a retrospective component to inquire about the incidence of cancer and cancer-related deaths during the three years preceding the date of inquiry (2010-2012). A convenient sample of 6,999 households with 40,688 inhabitants using multistage cluster sampling was surveyed involving all urban and rural areas of Basrah. The official cancer registration activities in Basrah seemed to have attained a high level of registration coverage (70-80%) but the gap, represented by missed cases, is still high enough to criticize the system. Most of the missing cases were either not notified by treating facilities or they were diagnosed and treated outside Basrah. Using a set of parameters, the pattern of cancer was consistent based on data of the household survey and data of the cancer registry but a gap still existed in the coverage of incident cancer and mortality by cancer registration. Integrated serious steps are required to contain the risk of cancer and its burden on the patient through improving the registration process, improving early detection, diagnostic and management capabilities and encouraging scientific research to explore the hidden risk factors and possible causes of low registration coverage. Periodic household surveys seemed feasible and essential to support routine registration.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.214-220
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• 2002

Objectives : To investigate the relationship of serum uric acid to cardiovascular risk factors in Korean male workers. Methods : We screened 522 male workers at an electrical manufacturing company by a periodic health examination and a questionnaire survey in 2000. We collected data relating to age, smoking status, alcohol drinking status, body mass index (BMI), blood pressure, serum lipid, fasting blood glucose and serum uric acid. The data were analyzed using a variety of methods, including ANOVA, Pearson's correlation, and multivariate regression analyses. to examine the association between uric acid and cardiovascular risk factors with a cross-sectional study design. Results : The concentration of serum uric acid showed positive associations with BMI, total cholesterol, triglyceride, and LDL-cholesterol; it was also significantly correlated to systolic and diastolic blood pressures. Life-style characteristics, such as smoking and alcohol drinking showed no significant association. From the multivariate regression analyses, BMI, total cholesterol and fasting blood glucose levels were found to be independent positive predictors of uric acid; while age, blood pressure and smoking status give no independent contribution explaining the variability of serum uric acid levels. Conclusions : This study demonstrates that serum uric acid level have a significant association with cardiovascular risk factors, such as BMI, total cholesterol and blood glucose in some Korean male workers.

• Economic and Environmental Geology
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• v.50 no.4
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• pp.267-276
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• 2017

Seawater intrusion into coastal fractured rock aquifer, resulting in groundwater contamination, is of serious concern in coastal areas of Jeolla Namdo, Korea, which heavily depends on groundwater resources. Time series analysis and forecasting were carried out to analyze and predict EC which is a major indicator of seawater intrusion. Two time series models of autoregressive integrated moving average (ARIMA) and seasonal autoregressive integrated moving average (SARIMA) were tested for suggesting appropriate time series model. Time series data of EC measured over one year showed a increasing trend with short periodic fluctuations, due to tidal effect and pumping, which indicated that EC time series data tended to be non-stationary. SARIMA model was found better fitted to observed EC than any other time series model. Time series analysis and modeling was found to be a useful tool to analyze EC at coastal fractured rock aquifer subject to seawater intrusion.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.1-13
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• 2017

The purpose of this study is to analyze a term of decade of water quality data of the Mulgum intake station on the Nakdong river(dam) to find the cause of algal blooms and to set an alternative to prevent artificial lake water pollution. Our study shows that water quality changes have regular periodic regularity and there was a certain correlation between specific analytical items. According to the analysis results of each factor, the decline in precipitation was not the main reason for algal blooms. TP concentration had a slight effect on Chl-a concentration but was not a limiting nutrient of a bloom. TN concentration had a strong correlation with Chl-a and strongly negative correlation with temperature, but was not a bloom's limiting nutrient, and was only a dependent variable. As the temperature was negatively correlated with the Chl-a concentration, it is found that the aspect of the ecological influence of the temperature was the most important factor of the phytoplankton concentration change. The N/P ratio lies under a power function with a high degree of reliability by the TP concentration, and the phenomenon appeared to be the same as the results of two other comparative areas. This result confirms that TN is dependent on TP and the biota in the lake that TN is a dependent variable whose concentration is determined by TP it. In conclusion, the increase in lake bloom is the result of a food chain change, and it is necessary to control the ecosystem by the food chain in the lake in order to reduce the lake's bloom. In particular, it is important to keep the benthic ecosystem as wide as possible in the aerobic state.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.157-174
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• 2006

Ajax interaction model changes the posture of web application to become a stateful over HTTP. Ajax applications are long-lived inthe browser. XMLHTTPRequest (XHR) is used to facilitate the data exchange. Using HTTPS over this interaction is not viable because of the frequency of data exchange. Moreover, switching of protocols form HTTP to HTTPS for sensitive information is prohibited because of server-of-origin policy. The longevity, constraint, and asynchronous features of Ajax application need to hove a different authentication and session fondling mechanism that invoke re-authentication. This paper presents an authentication and session management scheme using Ajax. The scheme is design lo invoke periodic and event based re-authentication in the background using digest authentication with auto-generated password similar to OTP (One Time Password). The authentication and session management are wrapped into a framework called AWASec (Ajax Web Application Security) for coupling to avoid broken authentication and session management.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.127-136
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• 2008

This paper proposes the efficient system for automatic design of FSS(Frequency Selective Surface) with periodic pattern and frequency characteristics specified by operator. The proposed system derives optimal design parameters through tool for analysis of FSS with arbitrary pattern, DB(Data Base) implemented from limited simulation and measurement data of FSS, and GA(Genetic Algorithm) for optimizing design parameters. FSS analysis tool consists of two analysis tools. One is the simulator for analysis of monolayer FSS that using moment method, another is the tool with approximated analysis method of FSS with dielectric layer. Given pattern configuration and characteristics specified by operators, the DB system searches the best matching FSS, and provides initial genes to GA from the searched parameters, which drastically reduces running time of GA for finding the FSS design parameters. In this paper, the proposed design system is verified through simulation and measurement about FSS with various patterns.

• The Journal of the Korean dental association
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• v.57 no.11
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• pp.644-653
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• 2019

Since 2013, adults aged over 20 can receive national health insurance scaling once a year in South Korea. In this study, we analyzed the usage status of national health insurance care service for periodontal disease in 2010-2018 by using Healthcare big data of the Health Insurance Review and Assessment Service. The increase rate of the dental care users was very high at 7.8 and 11.2% in 2013 and 2014, respectively. These are higher than the increase rate of all medical institution users, which is between -1.7 and 3.7%. In 2017, the rate of dental use was 44.4%, which has increased more than 10% compared to 2012. Percent receiver of national health insurance scaling was 19.5% in 2017. The 20s had the highest rate of 23.2%. The rate decreased with age. Based on these results, it can be evaluated that the expansion of national health insurance coverage for scaling improves accessibility to dental care. A more long-term assessment of the effect of periodic dental examination and scaling on reducing the prevalence of periodontal disease is needed. National health insurance coverage should be extended to oral hygiene education and supportive periodontal therapy in order to prevent periodontal disease.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.2
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• pp.32-41
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• 2001

The purpose of this study is to assess naturalness of each and use type for Daegu and provide the basic data for urban green space planning. The results are as follows: 1) As a result of periodic analysis, It is known that in the 1400´s that the rate of a-/oligo-/meso-hemeroby was over 90% of that area, in which naturalness was very high. By the 2020´s, the population will increase to about 3,500,000 and the occupation rae of meat-and poly-hemeroby, where naturalness is very low, is expected to increase rapidly. 2) The recent land uses of Daegu are divided ito 17 types. In the survey of a occupation rate of each land use type, a forest are occupies 48.8% of the entire area. The military installation zone is lowest with 0.07%. 3) Investigation of a dominant hemeroby grade in each land use type showed that the urban complex area in characterized by meta-hemeroby : and the space for pavement and building construction where naturalness is lowest. On the other hand, oligo-hemeroby that is worth being preserved was surveyed to be dominant in woodlands and natural forests. 4) In the analysis of hemeroby mapping in the process of a green space planning, it is clear that hemeroby will be used a s a tool that assesses the suitability for recreation activity of each sample case. For example, it enables a poly-hemeroby region to be utilized as a near-natural recreation area including $\beta$-and $\alpha$-euhemeroby region in Daegu. Besides, hemeroby can provide basic data to make a value judgement of each sample case with a view to preservation of nature.