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A Dynamic Frequency Allocation for Provisioning QoS in Cognitive Radio System (무선 인지 기반 시스템에서 QoS 보장 동적 주파수 할당)

  • Lee, Mun-Ho;Lee, Jong-Chan
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2008.10b
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    • pp.634-642
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    • 2008
  • Radio wave is the valuable resources in $21^{st}$ century. It will be widely used in various applications such as DMB, USN, telematics, and home network as well as mobile and wireless communications. Cognitive Radio technology is devised to maximize the utilization of radio resources by sensing near-by spectrum and dynamic and allocating free resources dynamically and adaptively. Wireless links for the secondary user need to be frequently switched to idle frequencies during the transmission of multimedia data in the cognitive radio based system. This may cause delay and information loss, and QoS degradations occur inevitably. The efficient frequency allocation scheme is necessary to support the seamless multimedia service to the secondary user while maintaining QoS of the primary user. This paper suggests a frequency selection scheme which considers other parameters such as cell load, data rate, and available bandwidth than just received signal strength during the frequency selection process. The performance of our proposed scheme is analyzed by simulation.

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Theory and Practice of Automatic Indexing (자동색인의 이론과 실제)

    • Journal of Korean Library and Information Science Society
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    • v.30 no.3
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    • pp.27-51
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    • 1999
  • This paper deals with the methods as well as the problems associated with automatic extraction indexing and assignment indexing, expert systems for indexing, and major approaches currently used to index the Internet resources. It also briefly reviews basic methods for establishing hypertext/hypermedia links automatically. The methods used in much of text processing today are not particularly new. Most of the them were used, perhaps in a more rudimentary form, 30 or more years ago by Luhn and many other investigators. Better results can be achieved today because much greater bodies of electronic text are now avaliable and the power of present-day computers allows the processing of such text with reasonable efficiency.

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Study on the correlation links between parameters of weather conditions and indicators of seed productivity of plants of spring wheat (Tr. aestivum L.) in Irkutsk region

  • Takalandze, Gennady Ordenovich
    • Journal of Species Research
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    • v.1 no.2
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    • pp.257-261
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    • 2012
  • In Irkutsk region the plants of spring wheat (Tr. aestivum) grow in three agro-ecological zones: steppe, forest-steppe and subtaiga. Due to this reason, the paper determines the coefficients of correlation between the indicators field germination of seeds, plant safety, productivity, temperature and moisture content of the plant habitat for each zone. The zonal moisture saving features of soil treatment for growing wheat plants (Tr. aestivum) are discussed on the basis of these data.

WebChemDB: An Integrated Chemical Database Retrieval System

  • Hou, Bo-Kyeng;Moon, Eun-Joung;Moon, Sung-Chul;Kim, Hae-Jin
    • Genomics & Informatics
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    • v.7 no.4
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    • pp.212-216
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    • 2009
  • WebChemDB is an integrated chemical database retrieval system that provides access to over 8 million publicly available chemical structures, including related information on their biological activities and direct links to other public chemical resources, such as PubChem, ChEBI, and DrugBank. The data are publicly available over the web, using two-dimensional (2D) and three-dimensional (3D) structure retrieval systems with various filters and molecular descriptors. The web services API also provides researchers with functionalities to programmatically manipulate, search, and analyze the data.

XLink Semantics in Object Repository for Guaranteeing Referential Integrity (객체지향 정보 저장소에서 참조 무결성 보장을 위한 XLink 시맨틱스)

  • 박희경;박상원;김형주
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.6
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    • pp.589-601
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    • 2003
  • XLink is XML Linking Language that defines links between XML documents or XML elements. It uses XML syntax to create structures that can describe links similar to the simple unidirectional hyperlinks of HTML, as well as more sophisticated links. There exist several relationships between resources that linked by XLink. Without supports from XML Repository for these relationship management, there is a huge overhead related to the management of relationships during both application development and maintenance, since the relationships need to be hard-coded directly into the application program itself. In this paper, we propose an XLink supporting system in object repository. We describe the design and implementation of this system on top of XDOM(persistent DOMlink XML repository). To support XLink, our system offers referential relationship semantics, extended link and the expansion of DOM tree for XLink.

Analysis of Global Food Market and Food-Energy Price Links: Based on System Dynamics Approach

  • Kim, Gyu-Rim
    • Korean System Dynamics Review
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    • v.10 no.3
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    • pp.105-124
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    • 2009
  • The situation of the global food markets has been being rapidly restructured and entering on a new phase by new dynamic and driving forces. The factors such as economic growth and income increase, high energy price, globalization, urbanization, and global climate change are transforming patterns of food consumption, production, and markets. The prices and markets of world food and energy are getting increasingly linked each other. Food and fuel are the global dilemma issues associated with the risk of diverting farmland or of consuming cereals for biofuel production in detriment of the cereals supply to the global food markets. An estimated 100 million tons of grain per year are being redirected from food to fuel. Therefore, the objectives of this study are as follows: Firstly, the study examines situations of the world food and energy resources, analyzes the trends of prices of the crude oil and biofuel, and formulates the food-energy links mechanism. Secondly, the study builds a simulation model, based on system dynamics approach, for not only analyzing the global cereals market and energy market but also forecasting the global production, consumption, and stock of those markets by 2030 in the future. The model of this study consists of four sectors, i.e., world population dynamics sector, global food market dynamics sector, global energy market dynamics sector, scenario sector of world economic growth and oil price.

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English-Korean Cross-lingual Link Discovery Using Link Probability and Named Entity Recognition (링크확률과 개체명 인식을 이용한 영-한 교차언어 링크 탐색)

  • Kang, Shin-Jae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.3
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    • pp.191-195
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    • 2013
  • This paper proposes an automatic method for discovering cross-lingual links from English Wikipedia documents to Korean ones in order to increase connectivity among vast web resources. Compared to the existing methods roughly estimating link probability of phrases, candidate anchors are selected from English documents by using various information such as title lists and linking probability extracted from Wikipedia dumps and the results of named-entity recognition, and the anchors are translated into Korean words, and then the most suitable Korean documents with the words are selected as cross-lingual links. The experimental results showed 0.375 of MAP.

A Study on Designing with RDF for manage of Web Service Metadata (웹 서비스 메타데이타 관리를 위한 RDF 설계에 관한 연구)

  • 최호찬;유동석;이명구;김차종
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.623-625
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    • 2003
  • The Semantic Web stands out in the next generation web, recently. In the Semantic Web, any information resources is defined by semantics and semantic links is given among these. It is different from existing web service environment. RDF (Resource Description Framework) is the data model to describe metadata of web resource and is to support for semantic links. And it is much the same as WSDL (Web Serice Description Language). In theis paper, we propose the RDF design method to improve the search performance by integrating RDF data unit with WSDL. We confirm the performance and efficiency of search will be improved by using the proposed method.

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A Novel Opportunistic Greedy Forwarding Scheme in Wireless Sensor Networks

  • Bae, Dong-Ju;Choi, Wook;Kwon, Jang-Woo;Choo, Hyun-Seung
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.4 no.5
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    • pp.753-775
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    • 2010
  • Greedy forwarding is a key mechanism of geographic routing using distance as a metric. As greedy forwarding only uses 1-hop neighbor node information, it minimizes routing overhead and is highly scalable. In existing greedy forwarding schemes, a node selects a next forwarding node based only on the distance. However, the signal strength in a realistic environment reduces exponentially depending on the distance, so that by considering only the distance, it may cause a large number of data packet retransmissions. To solve this problem, many greedy forwarding schemes have been proposed. However, they do not consider the unreliable and asymmetric characteristics of wireless links and thus cause the waste of limited battery resources due to the data packet retransmissions. In this paper, we propose a reliable and energy-efficient opportunistic greedy forwarding scheme for unreliable and asymmetric links (GF-UAL). In order to further improve the energy efficiency, GF-UAL opportunistically uses the path that is expected to have the minimum energy consumption among the 1-hop and 2-hop forwarding paths within the radio range. Comprehensive simulation results show that the packet delivery rate and energy efficiency increase up to about 17% and 18%, respectively, compared with the ones in PRR${\times}$Distance greedy forwarding.

Development of Project Success Model in Enterprise Using FCM (FCM을 이용한 기업프로젝트의 성공 모델 개발)

  • Park, Young-Man;Hwang, Seung-Gook;Park, Kwang-Bak;Lee, Young-Joo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.1
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    • pp.123-128
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    • 2010
  • To increase the chance of the success of project, it is necessary to identify the important factors influencing the performance of project. Cognitive map has been used for analysing by investigating causal links among relevant factors. A fuzzy cognitive map (FCM) is an extension of a cognitive map with the additional capability of representing feedback through weighted causal links. Project performance is influenced by several factors such as input resources, possibility of achievement, concern of others and so on. The object of this paper is to develop the project success model of enterprise using a fuzzy cognitive map approach to investigate the degree of causal relationship between project performance and these factors.