• Title/Summary/Keyword: peer-to-peer networks

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Implementation of UDP-Tunneling Based Multicast Connectivity Solution for Multi-Party Collaborative Environments (다자간 협업 환경을 위한 UDP 터널링 기반의 멀티캐스트 연결성 솔루션의 구현)

  • Kim, Nam-Gon;Kim, Jong-Won
    • Journal of KIISE:Computing Practices and Letters
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    • v.13 no.3
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    • pp.153-164
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    • 2007
  • The Access Grid (AG) provides collaboration environments over the IP multicast networks by enabling efficient exchange of multimedia contents among remote users; however, since lots of current networks are still multicast-disabled, it is not easy to deploy this multicast-based multi-party AG. For this problem, the AG provides multicast bridges as a solution by putting a relay server into the multicast networks. Multicast-disabled clients make UDP connections with this relay server and receive forwarded multicast traffics in unicast UDP packets. This solution is facing several limitations since it requires duplicate forwarding of the same packet for each unicast peer. Thus, in this paper, we propose an alternate solution for the multicast connectivity problem of the AG based on the UMTP (UDP multicast tunneling protocol). By taking advantage of flexibilities of UMTP, the proposed solution is designed to improve the efficiency of network and system utilization, to allow reuse of multicast-based AG applications without modification, and to partially address the NAT/firewall traversal issues. To verify the feasibility of proposed solution, we have implemented a prototype AG connectivity tool based on the UMTP, named as the AG Connector.

Meaning Structure of Green Infrastructure - A Literature Review about Definitions - (그린인프라스트럭처의 의미구조 - 기존문헌의 정의문 분석을 중심으로 -)

  • Lee, Eun-Sek;Noh, Cho-Won;Sung, Jong-Sang
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.2
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    • pp.65-76
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    • 2014
  • Green Infrastructure(GI) is suggested to recover urban water circulation system as a newly conceptual alternative methodology by Korean landscape field in recent years. In this context, the study considers the essential meaning of GI. The methodology of this study is literature review with 47 published papers which were peer-reviewed in international journals in the recent 5 years. These papers were collected from online database and academic archives. The main analysis targets are definition sentences about GI. The each sentences were interpreted by semantic structure between verbs and objects in the definition sentences. As the results, it figured out 5 aims('Provide', 'Improve', 'Produce', 'Conserve', 'Reduce'), 4 objects('Humanistic', 'Environmental', 'Ecological', 'Hydrological') and 3 spaces('Object space', 'Technically available spaces', 'Object or technically available spaces'). The '5 aims' connected with the elements of '4 objects' based on the '3 spaces'. The elements was connected to the '5 aims' via single form or 2~3 forms of the essential meaning networks of GI. The study provides 83 meaning networks to use landscape architecture planning and urban planning.

Systematic Review of Smoking Initiation among Asian Adolescents, 2005-2015: Utilizing the Frameworks of Triadic Influence and Planned Behavior

  • Talip, Tajidah;Murang, Zaidah;Kifli, Nurolaini;Naing, Lin
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.7
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    • pp.3341-3355
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    • 2016
  • Background: A recent WHO data report on mortality attributable to tobacco use including cigarette smoking indicated a very high burden of deaths in Asia and that people often initiate smoking as early as young adolescents. The objectives of this study were to systematically review peer-reviewed articles on cigarette smoking initiation among Asian adolescents and to develop a conceptual model of factors influencing smoking initiation by integrating all relevant factors based on existing data. Materials and Methods: Following a PRISMA guideline, a systematic review of articles published between 2005 and June 2015 was conducted using 5 databases on cigarette smoking initiation among adolescents (aged 10-19 years) living in Asia. We summarized the main findings of each study according to our research questions and data that emerged during the data extraction process. Analysis and categorization were based on the TTI and TPB models and classification of factors extracted from the study, were as follows: personal factors, social factors, broader environmental factors, mediators, and intention to initiate smoking and smoking behavior. Results: Of 1,227 identified studies, only 20 were included in this review. Our findings found that the mean age of cigarette smoking initiation ranged from 10 to 14 years and those who are more likely to initiate smoking are male, older adolescents, adolescents with low parental SES, individuals with low parental monitoring, low parental education level and having no discussion on smoking at home, those living in public housing and those exhibiting health-risk behavior. Our study also revealed that the risk of smoking initiation increased when they are exposed to smokers, influenced by peers, exposed to tobacco advertisements, receive pocket money, have lack of knowledge about smoking, have poor school performance, have a family conflict and have psychological problems. The conceptual model developed demonstrated complex networks of factors influencing initiation. Conclusions: This systematic review presents various factors influencing smoking initiation of the Asian adolescents and provides a conceptual framework to further analyze factors. Future studies should have a standard measure of smoking initiation, should analyze interactions and the intensity of relationships between different factors or variables in the conceptual model. This will in turn consolidate the understanding of the different factors affecting smoking initiation and will help to improve interventions in this area.

Types and Characteristics of Primary Teachers' Instructional Expertise Development Activities for Software Education (초등 교사의 SW교육 수업 전문성 개발 활동 형태 및 특성)

  • Ock, Jihyun;Ahn, Seongjin
    • Journal of The Korean Association of Information Education
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    • v.22 no.5
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    • pp.519-533
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    • 2018
  • This study aims to classify the types of instructional expertise development activities of teachers who teach subjects related to software education in primary schools. To this end, the study analyzes their participation in expertise development activities over the recent three years, outcomes from these activities, and forms and characteristics of expertise development activities. In the questionnaire survey conducted for this study, 276 primary school teachers participated. According to the survey, the same largest proportion of them participated in collective job training (96%) and distant job training (96%), followed by consulting, instruction supervision, mentoring, and peer observation (82%), lectures, workshops, and seminars held by related government ministries and the provincial and municipal offices of education (69%), and teachers' study communities (66%). Among informal activities, reading accounted for the highest portion of the activities (88%), followed by the use of information on Websites including YouTude and GitHub (80%), and teachers' expertise development networks (76%). The reasons for their participation in the activities were mostly to improve their instructional expertise (80%). Their participation in the activities had an impact on usefulness to enhance instructional expertise, improvement of job competencies, application to current jobs, sense of instructional efficacy, and positive effect. These results of the study are expected to provide a foundation for preparing continued expertise development plans that can promote the educational value of primary school teachers' instructional expertise development activities for teaching subjects related to software education.

Analysis of promising countries for export using parametric and non-parametric methods based on ERGM: Focusing on the case of information communication and home appliance industries (ERGM 기반의 모수적 및 비모수적 방법을 활용한 수출 유망국가 분석: 정보통신 및 가전 산업 사례를 중심으로)

  • Jun, Seung-pyo;Seo, Jinny;Yoo, Jae-Young
    • Journal of Intelligence and Information Systems
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    • v.28 no.1
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    • pp.175-196
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    • 2022
  • Information and communication and home appliance industries, which were one of South Korea's main industries, are gradually losing their export share as their export competitiveness is weakening. This study objectively analyzed export competitiveness and suggested export-promising countries in order to help South Korea's information communication and home appliance industries improve exports. In this study, network properties, centrality, and structural hole analysis were performed during network analysis to evaluate export competitiveness. In order to select promising export countries, we proposed a new variable that can take into account the characteristics of an already established International Trade Network (ITN), that is, the Global Value Chain (GVC), in addition to the existing economic factors. The conditional log-odds for individual links derived from the Exponential Random Graph Model (ERGM) in the analysis of the cross-border trade network were assumed as a proxy variable that can indicate the export potential. In consideration of the possibility of ERGM linkage, a parametric approach and a non-parametric approach were used to recommend export-promising countries, respectively. In the parametric method, a regression analysis model was developed to predict the export value of the information and communication and home appliance industries in South Korea by additionally considering the link-specific characteristics of the network derived from the ERGM to the existing economic factors. Also, in the non-parametric approach, an abnormality detection algorithm based on the clustering method was used, and a promising export country was proposed as a method of finding outliers that deviate from two peers. According to the research results, the structural characteristic of the export network of the industry was a network with high transferability. Also, according to the centrality analysis result, South Korea's influence on exports was weak compared to its size, and the structural hole analysis result showed that export efficiency was weak. According to the model for recommending promising exporting countries proposed by this study, in parametric analysis, Iran, Ireland, North Macedonia, Angola, and Pakistan were promising exporting countries, and in nonparametric analysis, Qatar, Luxembourg, Ireland, North Macedonia and Pakistan were analyzed as promising exporting countries. There were differences in some countries in the two models. The results of this study revealed that the export competitiveness of South Korea's information and communication and home appliance industries in GVC was not high compared to the size of exports, and thus showed that exports could be further reduced. In addition, this study is meaningful in that it proposed a method to find promising export countries by considering GVC networks with other countries as a way to increase export competitiveness. This study showed that, from a policy point of view, the international trade network of the information communication and home appliance industries has an important mutual relationship, and although transferability is high, it may not be easily expanded to a three-party relationship. In addition, it was confirmed that South Korea's export competitiveness or status was lower than the export size ranking. This paper suggested that in order to improve the low out-degree centrality, it is necessary to increase exports to Italy or Poland, which had significantly higher in-degrees. In addition, we argued that in order to improve the centrality of out-closeness, it is necessary to increase exports to countries with particularly high in-closeness. In particular, it was analyzed that Morocco, UAE, Argentina, Russia, and Canada should pay attention as export countries. This study also provided practical implications for companies expecting to expand exports. The results of this study argue that companies expecting export expansion need to pay attention to countries with a relatively high potential for export expansion compared to the existing export volume by country. In particular, for companies that export daily necessities, countries that should pay attention to the population are presented, and for companies that export high-end or durable products, countries with high GDP, or purchasing power, relatively low exports are presented. Since the process and results of this study can be easily extended and applied to other industries, it is also expected to develop services that utilize the results of this study in the public sector.