• Journal of Internet Computing and Services
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• v.11 no.4
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• pp.11-22
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• 2010

In case that group communication protocols assume every process is interested in all events occurring in a large scale group, the events multicasting to a subset of a large process group, such as a sensor network, potentially varying for every event based on their interests might lead to very high communication overhead on each individual process. Moreover, despite the importance of both guaranteeing message delivery order and supporting overlapped group using gossip based group communication for multicasting in sensor or P2P networks, there exist little research works on development of gossip-based protocols to satisfy all these requirements. In this paper, we present a new gossip-based causal message order guaranteeing multicast protocol based on local views and delegates representing subgroups and fully utilizing multi-group features to improve scalability. In the proposed protocol, the message delivery order in overlapped groups has been guaranteed consistently by all corresponding members of the groups including delegates. Therefore, these features of the proposed protocol might be significantly scalable rather than those of the protocols guaranteeing atomic order dependencies between multicast messages by hierarchical membership list of dedicated groups like traditional committee protocols and much stronger rather than fully decentralized protocols guaranteeing dependencies between multicast messages based on only local views. And the proposed protocol is a hybrid approach improving the inherent scalability of multicast nature by gossip-based technique in all communications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.90-95
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• 2000

In the Ordered Core Based Tree(OCBT) protocol, a core location is the most important feature to affect the performance. In this paper, the location placement of multiple level cores is studied. The proposed algorithm isthat each node in the network evaluates a sum of shortest path costs from all the other nodes and the entirenetwork is divided into a hierarchy region to have 3-logical level(Small, Medium, Large). The node to have thelowest cost in each S-Region is decided to be a core node. Then, the core nodes in the each S-Region evaluatea sum of shortest path costs from all the other core nodes in the same M-Region. The core node to have thelowest cost is decided to be the upper level core node. Similarly the highest level core node is decided in theL-Region. The proposed algoritthm is compared with conventional two methods to put the core nodes in thenetwork One is the random method to put the core nodes randomly. The other is the center method to locatethe core node at the nearest node from the center of each S-Region and then to locate the highest level corenode at the nearest core node from the center of the entire network. Extensive simulations are performed in theview of mean tree cost and join latency. Simulation results show that the proposed algorithm has betterperformance than random method or center method.

• The Journal of the Korea Contents Association
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• v.18 no.6
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• pp.467-480
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• 2018

The purpose of this study was to investigate gender difference of community-residing elderly's life satisfaction and influential factors. Data were collected from 461 elders aged 60+ with the cooperation of several social service center for the aged, senior centers, and senior citizen associations in Daejeon Metropolitan City and Chungcheongnam-do(Cheonan-si and Okcheon-gun). SPSS 22.0 software was used for t-test and cross tabulation analysis, correlation analysis, and hierarchical regression analysis. The results showed there was statistically significant difference of elderly's life satisfaction by gender in multivariate analysis including sociodemographic factors, social network and relationship with children variables, but no difference in bivariate analysis. There was also significant difference in the factors affecting community-residing elderly's life satisfaction by gender. A few factors like friend support, number of regular social gatherings, and subjective health status were statistically significant in predicting male elderly's life satisfaction. Predictors of female elderly's life satisfaction which were perceived elderly parent-children conflict, friend support, monthly income, subjective health status, support to children, support from children were more diverse, compared to the predictors for male elderly's life satisfaction. Based on the findings, suggestions for social welfare policy and practice to improve community-residing elderly's life satisfaction considering the gender difference were discussed.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.247-260
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• 2003

To share and standardize information, especially in the database environments, MDR (Metadata Registry) can be used to integrate various heterogeneous databases within a particular domain. But due to the discrepancies of data element representation between organizations, global information integration is not so easy. And users who are searching integrated information on the Web have limitation to obtain schema information for the underlying source databases. To solve those problems, in this paper, we present a 3-layered Information Integration System (LI2S) based on MDRs and Ontology. The purpose of proposed architecture is to define information integration model, which combine both of the nature of MDRs standard specification and functionality of ontology for the concept and relation. Adopting agent technology to the proposed model plays a key role to support the hierarchical and independent information integration architecture. Ontology is used as for a role of semantic network from which it extracts concept from the user query and the establishment of relationship between MDRs for the data element. (MDR and Knowledge Base are used as for the solution of discrepancies of data element representation between MDRs. Based on this architectural concept, LI2S was designed and implemented.

• Journal of Internet Computing and Services
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• v.22 no.1
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• pp.23-30
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• 2021

This paper proposes a noise-tolerant image classification system using multiple autoencoders. The development of deep learning technology has dramatically improved the performance of image classifiers. However, if the images are contaminated by noise, the performance degrades rapidly. Noise added to the image is inevitably generated in the process of obtaining and transmitting the image. Therefore, in order to use the classifier in a real environment, we have to deal with the noise. On the other hand, the autoencoder is an artificial neural network model that is trained to have similar input and output values. If the input data is similar to the training data, the error between the input data and output data of the autoencoder will be small. However, if the input data is not similar to the training data, the error will be large. The proposed system uses the relationship between the input data and the output data of the autoencoder, and it has two phases to classify the images. In the first phase, the classes with the highest likelihood of classification are selected and subject to the procedure again in the second phase. For the performance analysis of the proposed system, classification accuracy was tested on a Gaussian noise-contaminated MNIST dataset. As a result of the experiment, it was confirmed that the proposed system in the noisy environment has higher accuracy than the CNN-based classification technique.

• 한국노년학
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• v.36 no.3
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• pp.611-632
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• 2016

Solutions for elderly health issues need to be found that take into account not only a medical perspective, but also interactions with social conditions such as socioeconomic status. With this in mind, this study aims to understand how socioeconomic status leads to health inequalities for the elderly. Specifically, this study investigates the mediating effects of socioeconomic status(income and education levels), health activities as an intermediary of the three dimensions of physical health(medical health, functional health, subjective health), accessibility of medical facilities, social participation, and social network. To test the research model, a secondary data analysis was conducted on the 2014 National Survey of Senior Citizens. The participants of the study were 10,451 elderly men and women aged 65 and above. To test the mediated model, hierarchical multiple regression analysis was conducted following the procedures suggested by Baron and Kenny(1986). In addition, a Sobel test was conducted to test the mediated model's significance. According to the analysis, the effects of income and educational levels on the health of the elderly were not the same. Additionally, different results were found depending on health dimensions. However, the overall direction of the results showed that the socioeconomic status of the elderly creates health disparities, and health behaviors, accessibility of medical facilities, social participation, and social network had significant mediation effects between socioeconomic status and physical health. Study findings especially worth noting are as follows: education was shown to have a stronger effect on health than income; effects of social integration factors such as social participation were highlighted; and significant mediating effects on the accessibility of medical facilities remained even after taking residential area into account. Results of this study shed light on health inequality mechanisms due to socioeconomic conditions and the need to find alternatives to alleviate these problems.

• Journal of Convergence for Information Technology
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• v.11 no.8
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• pp.42-52
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• 2021

This study was conducted to identify the influence of the discrimination experienced in daily life and social isolation on depression among older adults living in the community. This study was a secondary analysis of the data of 2017 Living Profiles of Older Adults Survey. The participants was a representative sample among the older adults 65 years and older. Data from 10,041 older adults were analyzed for this study. Hierarchical logistic regression analyses were used. When the discrimination experiences was added in model 1, the likelihood of being depressed was 1.95(1.60-2.36) times higher for those who experienced discrimination comparing with those who didn't experienced discrimination. When the social isolation was added in model 2, the likelihood of being depressed was 1.89(1.55-2.30) times higher in those who experienced discrimination. In addition, as the number of close friends, neighbors, and acquaintances decreased by one, the likelihood of being depressed increased by 1.14 times. Those who were isolated from family, friends, neighbors and acquaintances were 3.90 times more likely to be depressed. Therefore, social efforts are needed to reduce the experience of discrimination. Maintaining a social network or creating a new network will contribute to lowering the level of depression in older adults who have experienced discrimination.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.361-368
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• 2010

It is general that mostly congested sections of national backbone networks have been improved based on the national network expansion plan. However, in case of intermodal terminals which are origins of logistics, it is still so congested that travel time between origin and destination is long. Therefore, intermodal transportation systems plan of major intermodal terminals for the intermodal connector networks between intermodal terminal and national backbone network or intermodal terminal was established. With the limitation of priority methodology applying to intermodal connector facility under existing methodology, this study suggests an improved priority methodology. This study includes characteristics of terminal on the hierarchical structure and assessment list, but it does not concentrate on the specific terminal type through survey. To avoid a certain concentration, budget constraint for each terminal type was considered ahead of priority. Finally priority methodology was developed with two-step assessment under consideration that specific terminal is not involved in intermodal connector facility project. As a result of calculating weights by survey, effects such as d/c and accessibility fluctuations index through project implementation gain high weight, and degree of region underdevelopment gets next. Although the methodology in this study could not yields the priority by assessment list, it will be useful for setting the direction on policy related to intermodal connector facility projects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.980-990
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• 2004

In this paper, we propose the dynamic bandwidth allocation algorithm for the IEEE802.3ah Ethernet Passive Optical Network(EPON) system to provide the fairness among terminals, and evaluate the delay-throughput performance by simulation. For the conventional EPON systems, an Optical Line Termination (OLT) schedules the upstream bandwidth for each Optical Network Unit (ONU), based on its buffer state. This scheme can provide a fair bandwidth allocation for each ONU. However, it has a critical problem that it does not guarantee the fair bandwidth among terminals which are connected to ONUs. For an example, we assume that the traffic from a greedy terminal increases at a time. Then, the buffer state of its ONU is instantly reported to the OLT, and finally the OW can get more bandwidth. As a result, the less bandwidth is allocated to the other ONUs, and thus the transfer delay of terminals connected to the ONUs gets inevitably increased. Noting that this unfairness problem exists in the conventional EPON systems, we propose a fair bandwidth allocation scheme by OLT with considering the buffer state of ONU as welt as the number of terminals connected it. For the performance evaluation, we develop the EPON simulation model with SIMULA simulation language. From the result of the throughput-delay performance and the dynamics of buffer state along time for each terminal and ONU, respectively, one can see that the proposed scheme can provide the fairness among not ONUs but terminals. Finally, it is worthwhile to note that the proposed scheme for the public EPON systems might be an attractive solution for providing the fairness among subscriber terminals.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.281-286
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• 2003

A large number of features are collected for problem solving in real life, but to utilize ail the features collected would be difficult. It is not so easy to collect of correct data about all features. In case it takes advantage of all collected data to learn, complicated learning model is created and good performance result can't get. Also exist interrelationships or hierarchical relations among the features. We can reduce feature's number analyzing relation among the features using heuristic knowledge or statistical method. Heuristic technique refers to learning through repetitive trial and errors and experience. Experts can approach to relevant problem domain through opinion collection process by experience. These properties can be utilized to reduce the number of feature used in learning. Experts generate a new feature (highly abstract) using raw data. This paper describes machine learning model that reduce the number of features used in learning using heuristic function and use abstracted feature by neural network's input value. We have applied this model to the win/lose prediction in pro-baseball games. The result shows the model mixing two techniques not only reduces the complexity of the neural network model but also significantly improves the classification accuracy than when neural network and heuristic model are used separately.