• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.919-921
• /
• 2002

본 논문에서는 기존의 Table-driven 방식과 On-demand 라우팅 의 장점을 접목시킨 2-tier 계층구조를 사용한 dynamic한 routing기법을 제안하며 , 구조적으로 취약한 보안 위협 요소들에 대한 안정성을 제공하는 인증 알고리즘을 제안하고 네트워크와 클러스터 헤드의 관리를 위한 신뢰할 수 있는 키 분배 메커니즘을 고찰한다. 또한 기존의 3GPP서비스와의 상호 연동 가능성을 고려하여 클러스터 헤더의 재생성과 강력한 신뢰성을 제공할 수 있는 알고리즘을 제안한다.

• Journal of Korean Society of Transportation
• /
• v.29 no.5
• /
• pp.55-65
• /
• 2011

In effort to estimate sustainability of the transportation sector, this study conducts a comparative analysis of methodology suggested for measuring greenhouse gas emission. There are two approaches proposed by the UN IPCC: 1) top-down approach (TDA) based on the amount oil sales, and 2) bottom-up approach (BUA) utilizing the velocity of moving source and traffic volume data. The subject areas for analysis were selected based on research results by the Korea Transportation Institute that evaluate traffic sustainability of each local government. Gwacheon-si being one of the top ranked areas in sustainability, and Anseong-si being ranked at the 7th level were analyzed. By the tier 1 methodology, Gwacheon-si and Anseong-si are estimated to create 74,813ton/yr, and 584,125ton/yr of the greenhouse gas emission, respectively. The tier 3 methodology, however, estimates Gwacheon-si and Anseong-si to create 91,462ton/yr, and 163,801ton/yr of the emission, respectively. Comparison of the two estimated emissions shows considerable differences; i.e., the tier 3 method over estimates Gwacheon-si's emission by 22.3% whereas it underestimates Anseong-si's greenhouse gas emission by the factor of about 3.5 compared to the emissions obtained from the tier 1 method. The result from this study implies that the traffic-sustainability-index based grade of each local government can be evaluated differently by the method adopted for measuring greenhouse gas emission.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.189.1-189.1
• /
• 2011

Global warming effect was intensified due to rapid growth of fossil fuel consumption caused by urbanization and industrialization. Various efforts was being done to solve the problems leading to anomaly climate such as flood, downpour, heavy snow. As a results of international efforts for management of global warming, Kyoto Protocol, which was passed in Kyoto, Japan in 1997, designated $CO_2$, $CH_4$, $N_2O$, HFCs, PFCs, $SF_6$ as a global warming gases. And IPCC(Intergovernmental Panel on Climate Change) suggested IPCC guideline for systematic establishment of national greenhouse gas inventory. Among five categories in IPCC guideline, the representative emission source of waste category is SWDS(solid waste disposal site). The concentrative research should progress for effective management of greenhouse gas related with waste. In this study, Tier1 and Tier2 methods which was suggested by 2006 IPCC(Intergovernmental Panel on Climate Change) guideline, was used to predict methane generation from C sanitary landfill located in Chungju area. To predict methane generation from C sanitary landfill, all factors were defaults values that were provided by 2006 IPCC guideline and Korea emission factors for Tier1 and Tier2 method. And economics of generated methane was estimated. From the predicted result using IPCC guideline, the methane generation was persistingly increased over a 9-year period(2000 ~ 2008). Aggregated amount of methane generation was about 3,017ton and 3,170ton predicted by Tier1 and Tier2, respectively. From the results of estimated economic value gained by generated methane from the C sanitary landfill for ten years from now(2010 ~ 2020), the profit was about 2.39 ~ 2.76 hundred million won.

• Journal of Digital Convergence
• /
• v.12 no.6
• /
• pp.93-103
• /
• 2014

The rapid trends toward outsourcing have created more complex and fragmented multi-tier supply chains for Engineering, Procurement & Construction(EPC) industry. Working with suppliers and sub-suppliers requires continuous integration activities during project execution. The purpose of this study is to identify the factors influencing the performances and relationship satisfaction of second-tier suppliers participating in the project-based supply chain. This study proposes the network embeddedness, collaboration, information-sharing and flexibility as antecedents variables, and collected the survey responses from the second-tier suppliers having experiences with complex projects. The statistical results indicate that the collaboration with supply chain leading firm and first-tier supplier has significant impact on the performances and relationship satisfaction of second-tier suppliers. It was also found that the information-sharing and flexibility influence the network embeddedness as well as collaboration, and that the embeddedness have significant impact on the collaboration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.10a
• /
• pp.970-973
• /
• 2003

Recently, the development paradigm of enterprise information system has been moved from 2-tier environment to 3-tier environment. 3-tier environment makes possible to develop more efficient system in terms of the performance, extension, deployment and maintenance. The ship drawing process management system which manages a long-term drawing process and a great number of designers has to support an accuracy and a real-time of information but it is impossible because it is still served in 2-tier environment and some process of them is not developed yet. In this paper, we implemented the analysis and design of system based on CBD(Component Based Development) for the purpose of hanging the environment from two-dimensional Client/server architecture environment to COM＋ based 3-tier architecture environment. And by completing a development of total system, the productivity and the efficiency of the ship drawing process management system will be improved. And a wide reuse of components makes possible to improve the productivity and efficiency of system.

• Journal of Korea Port Economic Association
• /
• v.30 no.1
• /
• pp.23-55
• /
• 2014

The purpose of this paper is to show the clustering trend and to choose the clustering ports for 3 Korean ports(Busan, Incheon and Gwangyang Ports) by using the self organizing maps based on neural network(SOM) and Tier models for 38 Asian ports during 11 years(2001-2011) with 4 input variables(birth length, depth, total area, and number of crane) and 1 output variable(container TEU). The main empirical results of this paper are as follows. First, clustering results by using SOM show that 3 Korean ports[Busan(26.5%), Incheon(13.05%), and Gwangyang(22.95%) each]can increase the efficiency. Second, according to Tier model, Busan(Hongkong, Sanghai, Manila, and Singapore), Incheon(Aden, Ningbo, Dabao, and Bangkog), and Gwangyang(Aden, Ningbo, Bangkog, Hipa, Dubai, and Guangzhou) should be clustered with those ports in parentheses. Third, when both SOM and Tier models are mixed, (1) efficiency improvement of Busan Port is greater than those of Incheon and Gwangyang ports. (2) Incheon port has shown the slow improvement during 2001-2007, but after 2008, improvement speed was high. (3) improvement level of Gwangyang port was high during 2001-2003, but after 2004, improvement level was constantly decreased. The policy implication of this paper is that Korean port policy planner should introduce the SOM, and Tier models with the mixed two models when clustering among the Asian ports for enhancing the efficiency of inputs and outputs.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10a
• /
• pp.178-180
• /
• 2000

오늘날 온라인 게임은 TCP망을 이용하여 동시에 수백에서 수천명이 접속하여 게임을 증길 수 있는 클라이언트/서버 모델의 표준이지만 서버에 접속하는 클라이언트의 수가 증가함에 따라 나타나는 많은 문제점을 가지고 있다. 본 논문에서는 기존 네트웍 게임 엔진 구조적 단점을 보완한 3-tier 방식을 적용한 분산 네트웍 게입 서버를 위한 부하 분산기의 연구 및 개발에 대하여 서술한다. 이 시스템은 클라이언트/서버 모델의 2-tier 방식에서 오는 클라이언트 수 증가에 따른 네트웍 부하 가중에 대한 처리 문제와, 분산된 2-tier 방식을 적용한 서버에서 각 서버간의 통신, 데이터 공유에 대한 문제 등을 다루고 이에 대한 해결책으로 3-tier 방식을 적용하여 클라이언트/서버 사이에 각 서버의 사용자나 이동되는 데이터를 분산하고 모니터링하는 부하 분산기 시스템을 적용하여 위와 같은 문제점을 해결하였다.

• Journal of Information Technology Applications and Management
• /
• v.25 no.2
• /
• pp.147-159
• /
• 2018

The changes of internet environment have made services through web application server (WAS) popular. Accordingly, technical difficulties in identifying users who access databases through WAS were incurred. In order to solve these problems, many companies adopt an agent-based approach for identifying users by installing additional software on WAS. However, this approach must submit to some disadvantages in terms of cost, maintenance, and development process. In this paper, we devise an non-agent based approach for identifying database users in 3-tier environments.

• Journal of Digital Convergence
• /
• v.14 no.8
• /
• pp.211-221
• /
• 2016

The rapid trends toward outsourcing and collaboration have created complex multi-tier supply chains for construction and engineering industries. Working with suppliers and sub-suppliers requires continuous integration activities in order to maximize the performances of the entire supply chain. The purpose of this study is to identify the factors influencing the performances and long-term business relationship of second-tier suppliers in directed sourcing environment. This study proposes the asset specificity, trust, information-sharing and collaboration, as antecedents variables, and collected the survey responses from the second-tier suppliers in rebar manufacturing works. The statistical results indicate that the asset specificity, trust, information-sharing and collaboration have significant influences on the long-term business relationship of rebar manufacturing second-tier suppliers, but trust has no impact on the performances of second-tier suppliers at 5% significance level. Practical implications are also discussed.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.7
• /
• pp.421-428
• /
• 2006

In this paper, the way of remote installation and back-up of 3-tier structure is introduced for efficient utilizing the cluster system resources distributed at several places. Recently, cluster system is constructed as the system of over hundreds nodes under complex network system mixed with public networks and private networks. Therefore, the as installation method suitable for the large scale cluster system and the remote recovery of failure nodes are important. However the previous researches which are based on 2-tier architecture may not provide the efficient cluster installation and image back-up method when the network of cluster system is composed of several private networks and public networks. In this paper, RISE (Remote Installation Service and Environment) based on the 3-tier architecture is proposed to solve this problem. In our approach, the managing node's role is divided into the global master node (GRISE) and the local master node (LRISE) to provide the efficient initial system deployment and remote failure recovery of distributed cluster system under the various network systems. Also, LRISE's availability is ensured under the complex network environments by adopting the auto-synchronization mechanism between GRISE and LRISE. In this work, a 64-node cluster system with gigabit network system is utilized for the experiment. From the experimental result, the system image with 1.86GB data can be obtained in 5 minutes and 53 seconds and the image-based installation of 64-node system can be carried out in 17 minutes and 53 seconds.