• The Bulletin of The Korean Astronomical Society
• /
• v.45 no.1
• /
• pp.66.2-66.2
• /
• 2020

We propose a deep learning analysis technique with a convolutional neural network (CNN) to predict the evolutionary track of the Epoch of Reionization (EoR) from the 21-cm differential brightness temperature tomography images. We use 21cmFAST, a fast semi-numerical cosmological 21-cm signal simulator, to produce mock 21-cm maps between z = 6 ~ 13. We then apply two observational effects, such as instrumental noise and limit of (spatial and depth) resolution somewhat suitable for realistic choices of the Square Kilometre Array (SKA), into the 21-cm maps. We design our deep learning model with CNN to predict the sliced-averaged neutral hydrogen fraction from the given 21-cm map. The estimated neutral fraction from our CNN model has great agreement with the true value even after coarsely smoothing with broad beam size and frequency bandwidth and heavily covered by noise with narrow beam size and frequency bandwidth. Our results show that the deep learning analyzing method has the potential to reconstruct the EoR history efficiently from the 21-cm tomography surveys in future.

• Electronics and Telecommunications Trends
• /
• v.39 no.1
• /
• pp.48-61
• /
• 2024

The integration of high-capacity terrestrial networks with non-terrestrial communication using satellites has become essential to support seamless low-latency services based on artificial intelligence and big data. Tunable light sources have been instrumental in resolving the complexity of channel management in wavelength division multiplexing (WDM) systems, contributing to increased network flexibility and serving as optical sources for long-distance coherent systems. Recently, these light sources have been applied to beam-steering devices in laser communication and sensing applications across ground, aerial, and satellite transport. We examine the utilization and requirements of tunable lasers in WDM networks and describe the relevant development status. In addition, performance requirements and development directions for tunable lasers used in optical interference systems and beam-steering devices are reviewed.

• Korean Journal of Social Welfare
• /
• v.39
• /
• pp.322-349
• /
• 1999

The purpose of the study is to investigate kinds of social support provided by various types of family members, relationships between types of family support and personal variables of the elderly and structural variables of the family network, and the relationships between family support and depression of the elderly. Here, family included a spouse, sons and daughters and their spouses, grandchildren, siblings and parents of an older person. Social support consisted of emotional, instrumental, financial help and social companionship. Two-hundred-eight older persons of age 60 years and over were interviewed. The main results of the study were as follows: an older person's spouse tended to provide more for emotional support, sons for financial help, daughters-in-law for instrumental support, and daughters for emotional and financial support. Some elderly were also provided for emotional support by parents and siblings. Possibility of daughters-in-laws and grandchildren as support providers was also verified. Various factors among personal and network-structural characteristics were significantly related to many types of social support provided by various types of family members. In general, while younger female elders, elders with good IADL ability or more frequent contacts with family members tended to have social support from more family members, support from daughters-in-law was provided to the elderly with less functional abilities. Various types of social support from a spouse were significantly related to depression level of the elderly. Their depression level was more related to whether or not sons and daughters-in-law exist rather than whether or not they provide social support. Practical methods to increase family support for the elderly were discussed.

• Journal of Korean Public Health Nursing
• /
• v.17 no.1
• /
• pp.35-46
• /
• 2003

The purpose of this study was to examine the self-rated health and to find various factors affecting it for elderly women in a rural community, to provide data necessary to establish health promotion programs for elderly. The subjects of the study included a total of 245 women with above 70 years of age reside in one rural community. VAS (Visual Analogue Scale) for self-rated health, Lawton's physical & instrumental activity of daily living scales, social network were evaluated. The results of the study were as follows: 1. The self-rated health of the elderly women were measured on a 100 point(VAS) scale and the score was 53.6, indicating that women rated their health as moderate. 2. Factors such as income(p=0.008), family size(p=0.031), the level of ADL(p=0.039), urinary symptom(p=0.039), nocturia(p=0.001), visual difficulty(p=0.023), the number of chronic diseases(p=0.015), presence of arthritis or neuralgia(p=0.015), social network(p=0.002), housework assistant(p=0.008), emotional support(p=0.031) were significantly related to self-rated health. 3. Through the stepwise multiple regression, social network, family size, visual difficulty, and housework assistant were identified as significant predictors of self-rated health(p<0.05), explaining $21.0\%$ of the variance of the dependent variable. Better understanding of the determinants of healthy aging hopefully will lead to effective interventions to improve the quality of life of the elderly.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.10
• /
• pp.6095-6101
• /
• 2013

Few studies have examined the relationship between social support and stages of adoption of cancer screening. Here we investigated associations between both structural and functional aspects of social support and stages of adoption of gastric cancer screening in the general population of Korea. The study population was derived from the 2011 Korean National Cancer Screening Survey (KNCSS), an annual cross-sectional survey that uses nationally representative random sampling to investigate cancer screening rates. Data were analyzed from 3,477 randomly selected respondents aged 40-74 years. Respondents were classified according to their stage of adoption of gastric cancer screening: precontemplation (13.2%), contemplation (18.0%), action/maintenance (56.1%), relapse risk (8.5%), and relapse stage (4.1%). Respondents with larger social networks were more likely to be in the contemplation/action/maintenance, or the relapse risk/relapse stages versus the precontemplation stage (OR=1.91, 95%CI: 1.52-2.91; p for tend=0.025). Emotional and instrumental supports were not associated with any stage of adoption of gastric cancer screening. However, respondents who reported receiving sufficient informational support were more likely to be in the relapse risk/relapse stages versus the precontemplation, or the contemplation/action/maintenance stage (p for trend=0.016). Interventions involving interactions between social network members could play an important role in increasing participation in gastric cancer screening.

• The Journal of Engineering Geology
• /
• v.10 no.2
• /
• pp.79-97
• /
• 2000

Trend of earthquake occurrence of Korea represents that the term from 1978 to 1982 may be called as "active period", the term from 1983 to 1991 is rather tranquil, and from 1992, the occurrence number is increasing greatly. Instrumental earthquake observation of Korea started in 1905 by Japan. It continued until 1943 and ceased then through social disorders such as the independence from Japan Empire and the civil war. After that the observation restarted in 1963 by the establishment the World Wide Standard Seismograph Network. And the fundamental earthquake observation period started in 1978 with the Hongsung earthquake event. KMA(Korea Meteorological Administration) has constructed and operated the 24-hour earthquake and tsunami monitoring system and it propels new construction project of the national seismographic network system. In the result of this project, KMA operates 27 seismic networks, 42 accelerator networks, seismic analyzing system, and sea level monitoring system now. It has the plan to enlarge these systems that 31 seismic networks and 75 accelerator networks until 2001.

• Survey Research
• /
• v.10 no.3
• /
• pp.85-106
• /
• 2009

This study is an attempt to provide some answers to question about how characteristics and general recognition regarding internet use in Korea and Japan influence fostering and maintaining on-line social network in each of countries. Survey is used to compare Korean internet users and Japanese internet users in terms of characteristics of on-line social network, individual's propensity for internet use, including their recognition on internet. The study's main findings go as follows. First, Korean internet users tend to be more active in using internet than Japanese internet users do, thus having larger on-line social network and more intensive internet use than Japanese internet users do. However, there is a commonality that majority of internet users in both countries use internet to connect them to person with whom they have private relationship but they cannot meet frequently. Second, for Korean internet users, individual's propensity, characteristics, and recognition regarding internet use is not related to how to contact others. To the contrary, for Japanese internet users, how to contact others in on-line setting seems to vary according to whether or not they have relation-oriented internet use and how they recognize the availability of internet. Third, a commonality regarding the size of on-line social network is found between Korea and Japan that the total numbers of people enrolled as network increases if people use internet in order to get information. This confirms previous finding that relationship based on weak tie is instrumental in fostering on-line social relations and likely produces advantage in getting information. Finally, for Japanese internet users, the degree of risk recognized in on-line setting, that is the degree of interpersonal trust, appears to greatly influence overall relationship -building in on-line.

• Journal of Digital Convergence
• /
• v.19 no.3
• /
• pp.401-414
• /
• 2021

The purpose of this study was to examine the associations of Korean older adults' use of Social Network Service (SNS) and text messages with frequency of contact with 1) non-coresident adult children, 2) siblings and relatives, or 3) friends, neighbors, and acquaintances. Data were drawn from the 2017 Survey of Living Conditions and Welfare Needs of Korean Older Persons 65+ (N=8,392), and older adults were categorized into 4 groups depending on their familiarity with use of SNS and text messages. Ordinary Least Squares regression models were estimated for analyses. Results revealed that older users of both types of communication media reported frequent exchanges of calls, text messages, etc. with both family and friends. However, using SNS and text messages was consistently related to more face-to-face contact with non-family members. To conclude, older adults' familiarity with communication media could be key to exchanges of emotional and instrumental support with informal social network members and quality of life in the community. Overall, our results highlight the importance of information communication education targeting older adults for continued involvement with their informal social network members.

• Culinary science and hospitality research
• /
• v.24 no.2
• /
• pp.34-43
• /
• 2018

The objective of this study was to acquire a general and text-based awareness and recognition of cruise food hygiene through big data analytics. For the purpose, this study collected data with conducting the keyword "food hygiene, cruise" on the web pages and news on Google, during October 1st, 2015 to October 1st, 2017 (two years). The data collection was processed by SCTM which is a data collecting and processing program and eventually, 899 kb, approximately 20,000 words were collected. For the data analysis, UCINET 6.0 packaged with visualization tool-Netdraw was utilized. As a result of the data analysis, the words such as jobs, news, showed the high frequency while the results of centrality (Freeman's degree centrality and Eigenvector centrality) and proximity indicated the distinct rank with the frequency. Meanwhile, as for the result of CONCOR analysis, 4 segmentations were created as "food hygiene group", "person group", "location related group" and "brand group". The diagnosis of this study for the food hygiene in cruise industry through big data is expected to provide instrumental implications both for academia research and empirical application.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.131.2-131.2
• /
• 2011

We present performance of artificial neural network multivariate classifier in identifying non-astrophysical origin noise transients from the gravitational wave channel of Laser Interferometer Gravitational-wave Observatory (LIGO). LIGO has successfully conducted six science runs, achieving the sensitivity as planned and producing many fruitful scientific results. It has been well observed that the detector noise is non-Gaussian and non-stationary, which results in large excess of noise transients called glitches arising from instrumental and environmental artifacts. Great efforts have been committed to reduce the glitches by tuning the detector instruments and by vetoing them but further improvement is still needed. To this end, there have been efforts to incorporate data from hundreds of auxiliary, physical and environmental channels into identifying the glitches in the gravitational wave channel. We introduce a multivariate classification method using Artificial Neural Networks (ANNs) that efficiently handles large number of variables. In this poster, we present preliminary results of the application of our ANN algorithm to data from LIGO's Science Run 4 and compare its performance with conventional vetoing method.