• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.418-424
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• 2013

Both simulation and physical implementation are valuable tasks in sensor network routing protocols. In this paper, we propose an efficient underground utilities monitoring method within several constraints using wireless sensor network. First, in order to physically implement protocol of network which is applied, the distributed event-based simulation, which applies an existing nesC codes of sensor network routing protocols, is implemented and analyzed. Also, we have performed the simulation and analyzed the execution results for application model of routing protocols for monitoring underground utilities in the VIPTOS(Visual Ptolemy and TinyOS) environments which combine TOSSIM and Ptolemy II based on distributed event.

• Journal of the Korean Society for information Management
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• v.14 no.1
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• pp.47-76
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• 1997

This study explores the importance of OSI standards in library environment and specifically of Z39.50/SR information retrival protocols and ILL protocol. Libraries and other information systems need to implement these ap lication protocols in order to facilitate the sharing of library information resources through information networks. The foreign systems which have implemented the standard protocols are reviewed in this paper, and it is suggested that search results of OPACs and other bibliographic databases be directly used for electronic document request for fast document delivery, first by implementing Z39.50 OPACs and standard interlibrary loan systems and next by integrating the two systems in Korean electronic libraries.

• Journal of Internet Computing and Services
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• v.5 no.5
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• pp.39-48
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• 2004

For transporting real-time multimedia traffic, RTP is considered as one of the most promising protocols operating at application layer. In order to manage and control the real-time multimedia traffic within networks, network managers need to monitor and analyze the traffic delivering through their networks. However, conventional traffic analyzing tools can not exactly classify and analyze the real-time multimedia traffic using RTP on the basis of real-time as well as non-real-time operations. In this paper, we propose an efficient online classification method of RTP packets, which can be used on high-speed network links. The accuracy and efficiency of the proposed methodhave been tested using captured data from a KIX node with 100 Mbps links, which interconnects between domestic and overseas Internet networks and is operated by NCA.

• Journal of the Korean Society for information Management
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• v.13 no.2
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• pp.223-242
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• 1996

This study proposes an integration model of information retrieval systems using a standard distributed object computing technology in digital library environments. In the proposed integration model called DDIRIORB, the middleware broker based on CORBA is designed for the transparent access to the distributed information repositories and the consistent view of the information retrieval by applying 239.50 protocol. The DDIRIORB is an adaptable open architecture that allows for the following benefits : bibliographic and abstract information retrieval simultaneously, interoperability between application servers and clients, consistent view of search results, complexity reduction of integration interfaces, and easy to use.

• Journal of Korean Library and Information Science Society
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• v.38 no.3
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• pp.297-320
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• 2007

This study examined the main concepts of SOA and Web Services, and conducted technical analysis of major Web Services protocols such as SOAP, REST, SRW/U, and OAI-PMH that realize SOA, and suggested examples of SOAP and REST based Web Services establishments in foreign and domestic libraries respectively. In addition, it introduced application examples of Library 2.0 using Web 2.0 technology in foreign and domestic libraries and suggested how to apply SOA based Web Services protocol in Library 2.0. Finally, it proposed how to put Library 2.0 into practice applying meta-searching system integrating library OPAC, online bookstores, web portal sites and library union catalogs using REST based Open API.

• Journal of Multimedia Information System
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• v.2 no.3
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• pp.287-294
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• 2015

We are living in epoch of information when Internet touches all aspects of our lives. Therefore, it provides a plenty of services each of which benefits people in different ways. Electronic Mail (E-mail), File Transfer Protocol (FTP), Voice/Video Communication, Search Engines are bright examples of Internet services. Between them Social Network Services (SNS) continuously gain its popularity over the past years. Most popular SNSs like Facebook, Weibo and Twitter generate millions of data every minute. Twitter is one of SNS which allows its users post short instant messages. They, 100 million, posted 340 million tweets per day (2012)[1]. Often big amount of data contains lots of noisy data which can be defined as uninteresting and unclassifiable data. However, researchers can take advantage of such huge information in order to analyze and extract meaningful and interesting features. The way to collect SNS data as well as tweets is handled by crawlers. Twitter crawler has recently emerged as a great tool to crawl Twitter data as well as tweets. In this project, we develop Twitter Crawler system which enables us to extract Twitter data. We implemented our system in Java language along with MySQL. We use Twitter4J which is a java library for communicating with Twitter API. The application, first, connects to Twitter API, then retrieves tweets, and stores them into database. We also develop crawling strategies to efficiently extract tweets in terms of time and amount.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.529-532
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• 2011

Recently research efforts for ubiquitous technology that includes RFID(Radio Frequency Deification and sensor networks are conducted very actively The architectural framework of the USN sensor network discovery service. The survey of the USN technology is conducted on four technological visions that contain USN system technology USN networking technology and USN middleware along with the service platform, With respect to each technological division domestic and worldwide leading research projects are primarily explored with their technical features and research projects are primarily explored with their technical features and research outputs. Boasted on the result of the survey we establish a USN software model that includes data sensing, sensor data storage sensor data storage sensor data naming and sensor feed name service. This main objective of this model is to provide a reference model for the facilitation of USN application developments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.641-649
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• 2004

We propose a dynamic traffic management model which uses adaptive priority reassignment algorithm to deliver service differentiation in home networks, and implement adaptive priority reassignment algorithm using FPGA. The proposed architecture is designed to handle home network traffic without the need for signaling protocol. We categorize home network traffic into three kinds of traffic class: control data traffic class, the Internet data and non-real-time data traffic class, and multimedia data traffic class (include non-real-time and real-time multimedia data traffic). To support differential service about these kinds of traffic class, we designed and implemented a traffic management framework that dynamically change each traffic class priority depending on bandwidth utilization of each traffic class.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.1
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• pp.21-28
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• 2009

In this paper, we consider the Femtocell based enterprise wireless network using 2G/3G/4G cellular network technologies. And, we apply the open network service API which enable an easy development of ISP or enterprise services to P2P enterprise services. Based on the proposed scheme, enterprise services can be always connected at anywhere and anytime via heterogeneous devices. By using a qualitative analysis, we evaluate the performance of the proposed scheme and compare with that of the famous P2P service - Skype. Results show that the proposed scheme requests smaller servers and flows with enhanced service quality.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.6
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• pp.345-352
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• 2010

In this study, external condensation heat transfer coefficients(HTCs) of R134a and R1234yf are measured on a plain, low fin, and Turbo-C tubes at the saturated vapor temperature of $39^{\circ}C$ with the wall subcooling of $3{\sim}8^{\circ}C$. R1234yf is a new alternative refrigerant of low greenhouse warming potential for replacing R134a which is one of the greenhouse gases controlled by Kyoto protocol and is used extensively in mobile air-conditioners. Test results show that the external condensation HTCs of R1234yf are very similar to those of R134a for all three surfaces tested. For the application of condensation heat transfer correlations to the design of condensers charged with R1234yf, thorough property measurements are needed for R1234yf in the near future.