• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.474-483
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• 2003

The secret sharing is the basic concept of the threshold cryptosystem and has an important position in the modern cryptography. At 1995, Jarecki proposed the proactive secret sharing to be a solution of existing the mobile adversary and also proposed the share renewal scheme for (k, n) threshold scheme. For n participants in the protocol, his method needs O($n^2$) modular exponentiation per one participant. It is very high computational cost and is not fit for the scalable cryptosystem. In this paper, we propose the efficient share renewal scheme that need only O(n) modular exponentiation per participant. And we prove our scheme is secure if less that ${\frac}\frac{1}{2}n-1$ adversaries exist and they static adversary.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.89-97
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• 1999

Through manifestation of the principles of commodity production spatial sharing of labour can be observed in the agriculture as well as in cattle production. Better adjustment of the production structure to the environment factors brings higher yields and more effective production. In being able to maximize the profit the entrepreneurs opt for producing output that closely matches to their featuring conditions. In contrary to the relatively high "mobility" of crop production animal husbandry and within this cattle production - as known - is strictly chained to forage production. On the basis of our economic research and as a result of multivariable analysis(factor analysis) it can be concluded that two variable groups(factors) are highly dominant in organizing profitable cattle production. First of them is the crop site factor (indicated by gold crown value), the second is the forage production feature(forage and grassland area and the yield of them). During recent years the weight of environmental factors suffered from devaluation. As a result of the central economic administration differentiating effects were suppressed and the chances of equalizing concepts strengthened. The outcome can be observed even today. In the regions, for example, being predominantly suitable for grass and forage cropping the milk and slaughter cattle production decreased. The same is ture for com and pig production regions. Unexploitment of local environmental features can be observed mainly in grassland management. Branches being potential user of grasslands hardly take them into consideration. Main method of rational use of grasslands is pasturing. Presence of pastures and the usage of them through cattle production is highly important not only for profitable production but also for maintaining ecological stability.

• Korean Journal of Family Social Work
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• no.55
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• pp.265-297
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• 2017

This study aims to provide basic information about the policy and system improvements relevant to single elderly men, through an investigation concerning the use and needs of activity spaces near their housing environments. Eighteen single elderly men over 60-years-old living in Gunsan city of Jeonbuk province in Korea participated in in-depth interview, and the data were qualitatively analyzed. The results of the study are as follows: The social networks of the participants were focused on friends or colleagues, while mutual exchanges with their children were intermittently undertaken. Natural networks of the elderly were formed mainly in third places, such as parks, restaurants, or community facilities, and about a half of the elderly participants had no spatial needs, and the rest required spaces for meal services, the elderly living community, jobs, leisure/hobby activities, or facility improvements. The elements influencing use of activity spaces were access from the residence, health, social networks, and economic conditions. The results suggest the following: Exercise or leisure facilities supporting elderly mobility should be set up close to their residential environments. Senior facilities centered on systematic supports and shuttle buses circulating around the places that the elderly visit frequently should be considered. On the other hand, regular maintenance and education on residents' proper use of the facilities, and sufficient information and fee discounts for the general programs are needed so that the elderly could interact with the younger generation. From a public perspective, a rational system and policy based on understanding single elderly men's needs should be prepared for provision and management of the activity space.

• 재활복지
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• v.21 no.1
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• pp.71-95
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• 2017

The purpose of this research is to suggest implications for the elderly with disability by taking a look at the influence of disability of elderly on successful aging and a moderating effect of social support network. This study analyzed the $4^{th}$ panel data from KReIS and the subjects for this research are 3,906 of elderly aged over 65 years. For the statistical analysis, the IBM SPSS Statistics v23.0 program was utilized. Technical statistics was verified, multiple regression analysis was used in order to take a look at the effects of moderating variable. The results of this research are as the following: Firstly, the disability of elderly had an negative effect on successful age. Secondly, as a social support network, friend & neighborhood network and family network had an positive effect on successful age. Thirdly, friend & neighborhood network among social support network had a moderating effect on successful aging. In other words, the more disabled the elderly are, the lower the level of successive aging became, it turned out that the bigger the social support of friend & neighborhood network, the less the negative effect of disability on successive aging. On the basis of the result, it was proposed a case management for the elderly with disability, assurance of mobility right, and self-help meeting program for social support network.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.3
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• pp.45-52
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• 2018

Currently, apartments have become an important research subject for the overall area of politics, economics, and culture as well as urban architectural study. However, there are few analyses of the research trends related to the current interest in the apartment research and prediction of the future changes of an apartment in politics and industry. In this study, the research information related to the apartment has classified, and the changes in the research trends have analyzed. Based on the classified data, the first thesis and dissertation related to the apartment and changes of academic notation have discovered. In addition, future interests and future research directions through Frequency of Appearance, Degree Centrality Analysis, and Betweenness Centrality Analysis of author keywords were predicted. As a result of the analysis, 'Space,' 'Residential Mobility' and 'Apartment Complex' studies were found to be important research topics throughout the entire period. 'Han Gang Apartment,' 'Small Size Apartment,' 'Civic Apartments,' 'Jamsil,' and 'Child' were newly interested topics until 70's era. '(Super) High-rise Apartment,' 'Perception,' 'Jugong Apartment,' 'Housing Environment,' 'Housewife,' 'Apartment Layout,' and 'Busan' were newly interested topics during the 80's and 90's era. 'Apartment Price,' 'Energy,' 'Remodeling,' 'Noise,' 'Resident Satisfaction,' 'Community,' and 'Apartment Lotting-out' were newly interested topics after the year 2000. New concerns for last decade are found to be 'Super High-rise Apartment', 'Remodeling', 'Indoor'(2007), 'Apartment Reconstruction Project', 'Brand', 'AHP', 'Housing Environment'(2008), 'Ventilation'(2009), 'Apartment Lotting-out'(2010), 'Economic Assessment'(2011), 'Cost'(2012), 'Green Building', 'Apartment Sales', 'Law', 'Society'(2013), 'Floor Impact Noise', 'Seoul'(2014), 'Noise'(2015), 'Hedonic Model'(2016). In addition, following research topics are expected to be active in the future: In maturity stage of the research development is going to be 'Apartment Price', 'Space', 'Management of Apartment Housing'; the hedonic model, which is research growth and development stage, is going to be '(Floor Impact) Noise', 'Community', 'Energy.

• Atmosphere
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• v.31 no.2
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• pp.241-249
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• 2021

A smart city utilizes data collected from various sensors through the internet of things (IoT) and improves city operations across the urban area. Recently substantial research is underway to examine all aspects of data that requires for the smart city operation. Atmospheric data are an essential component for successful smart city implementation, including Urban Air Mobility (UAM), infrastructure planning, safety and convenience, and traffic management. Unfortunately, the current level of conventional atmospheric data does not meet the needs of the new city concept. New and innovative approaches to developing high spatiotemporal resolution of observational and modeling data, resolving the complex urban structure, are expected to support the future needs. The geographic information system (GIS) integrates the atmospheric data with the urban structure and offers information system enhancement. In this study we proposed the necessity and applicability of the high resolution urban meteorological dataset based on heavy fog cases in the smart city region (e.g., Sejong and Pusan) in Korea.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.13-29
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• 2003

Web-mail system is worthy of note as a next generation e-mail system for its mobility and easiness. But many web-mail system does not have any kind of security mechanism. Even if web-mail system provides security services, its degree of strength is too low. Using these web-mail systems, the e-mail is tabbed, modified or forged by attacker easily. To solve these problems, we design and implement secure web-mail system based on the international e-mail security standard S/MIME in this thesis. This secure web-mail system is composed of server system and client system The server system performs basic mail functions - sending/receiving the mails, storing the mails, and management of user information, etc. And the client system performs cryptographic functions - encryption/decryption of the mails, digital signing and validation, etc. Because client system performs cryptographic functions this secure web-mail system gives its reliability and safety, and provides end-to-end security between mail users. Also, this secure web-mail system increase system efficiency by minimize server load.

• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.29-38
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• 2004

In this study, we investigated the thermal properties of corn-starch filled polybutylene succinate-adipate (PBS-AD) bio-composites. Thermal analysis (TA) is used to describe the analytical method for measuring the chemical property and weight loss of composite materials as a function of temperature. The thermal stability of corn-starch was lower than that of pure PBS-AD. As corn-starch loading increased, the thermal stability and degradation temperature of the bio-composites decreased and the ash content increased. It can be seen that the degree of compatibility and interfacial adhesion of the bio-composites decreased because of the increasing mixing ratio of the corn-starch. As the content of corn-starch increased, there was no significant change in the glass transition temperature (T_g) and the melting temperature (T_m) for the bio-composites. The storage modulus (E') and loss modulus (E") of the corn-starch flour filled PBS-AD bio-composites were higher than those of PBS-AD, because of the incorporation of corn-starch increased the stiffness of the bio-composites. At higher temperatures, the decreased storage modulus (E') of bio-composites was due to the increased polymer chain mobility of the matrix polymer. From these results, we can expect that corn-starch has potential as a reinforcing filler for bio-composites. Furthermore, we recommend using a coupling agent to improve the interfacial adhesion between corn-starch and biodegradable polymer.

• Smart Media Journal
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• v.11 no.11
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• pp.49-62
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• 2022

Recently, with the development of Smart City Solutions such as Big data, AI, IoT, Autonomous driving, and Digital twins around the world, the proliferation of various smart devices and social media, and the record of the deeds that people have left everywhere, the construction of Smart Cities using the "Big Data" environment in which so much information and data is produced that it is impossible to gauge the scale is actively underway. The Purpose of this study is to construct an objective and systematic analysis Model based on Big Data to improve the transportation convenience of citizens and formulate efficient policies in Urban Information and Public Transportation accessibility in sustainable Smart Cities following the 4th Industrial Revolution. It is also to derive the methodology of developing a Big Data-Based public transport accessibility and policy management Platform using a sustainable Urban Public DB and a Private DB. To this end, Detailed Living Areas made a division and the accessibility of basic living amenities of Gwangju Metropolitan City, and the Public Transportation system based on Big Data were analyzed. As a result, it was Proposed to construct a Big Data-based Urban Information and Public Transportation accessibility Platform, such as 1) Using Big Data for public transportation network evaluation, 2) Supporting Transportation means/service decision-making based on Big Data, 3) Providing urban traffic network monitoring services, and 4) Analyzing parking demand sources and providing improvement measures.

• Journal of Preventive Medicine and Public Health
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• v.56 no.5
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• pp.467-474
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• 2023

Objectives: Diabetes mellitus (DM) is a serious public health issue that places a heavy financial, social, and health-related burden on individuals, families, and healthcare systems. Self-reported health-related quality of life (HRQoL) is extensively used for monitoring the general population's health conditions and measuring the effectiveness of interventions. Therefore, this study investigated HRQoL and associated factors among patients with type 2 DM at a primary healthcare center in Indonesia. Methods: A cross-sectional study was conducted in Klaten District, Central Java, Indonesia, from May 2019 to July 2019. In total, 260 patients with DM registered with National Health Insurance were interviewed. HRQoL was measured with the EuroQol Group's validated Bahasa Indonesia version of the EuroQoL 5-Dimension 5-Level (EQ-5D-5L) with the Indonesian value set. Multivariate regression models were used to identify factors influencing HRQoL. Results: Data from 24 patients were excluded due to incomplete information. Most participants were men (60.6%), were aged above 50 years (91.5%), had less than a senior high school education (75.0%), and were unemployed (85.6%). The most frequent health problems were reported for the pain/discomfort dimension (64.0%) followed by anxiety (28.4%), mobility (17.8%), usual activities (10.6%), and self-care (6.8%). The average EuroQoL 5-Dimension (EQ-5D) index score was 0.86 (95% confidence interval [CI], 0.83 to 0.88). In the multivariate ordinal regression model, a higher education level (coefficient, 0.08; 95% CI, 0.02 to 0.14) was a significant predictor of the EQ-5D-5L utility score. Conclusions: Patients with diabetes had poorer EQ-5D-5L utility values than the general population. DM patients experienced pain/discomfort and anxiety. There was a substantial positive relationship between education level and HRQoL.