• Title/Summary/Keyword: access

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Global Scenario of Open Access Publishing: A Decadal Analysis of Directory of Open Access Journals (DOAJ) 2003-2012

  • Pandita, Ramesh;Ramesha, B.
    • Journal of Information Science Theory and Practice
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    • v.1 no.3
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    • pp.47-59
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    • 2013
  • The present study aims to assess the growth of open access journals at a global level. The concept of Open Access (OA) publishing is being well received among academic circles and as a result we can see more and more scholarly content is being made these days available in open access format. The present study is simply an attempt to assess the trend and growth of open access journals during the last decade, viz. for the period 2003-2012, for which data has been retrieved from the Directory of Open Access Journals (DOAJ), which as of date hosts more than 9700 journals from 120 countries across the world covering major languages of the world. But keeping in view the period of our study the data has been retrieved as per our applicability, which as a result confines our study to 8453 journals only. The directory covers 18 main subject areas having 76 sub-disciplines, each having on average 118.53 journals. During the entire decade the number of countries which entered into OA publishing rose from 49 to 120 with a growth of 144%, and if this growth rate continues to be the same for the next five years, viz. by 2018, the world will turn into 100% open access. At the continental level Europe leads the tally by publishing a maximum of 3140 OA journals contributed by 43 countries across Europe, which again is the highest number from any continent.

eMCCA: An Enhanced Mesh Coordinated Channel Access Mechanism for IEEE 802.11s Wireless Mesh Networks

  • Islam, Md. Shariful;Alam, Muhammad Mahbub;Hong, Choong-Seon;Lee, Sung-Won
    • Journal of Communications and Networks
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    • v.13 no.6
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    • pp.639-654
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    • 2011
  • In this paper, we present a channel access mechanism, referred to as the enhanced mesh coordinated channel access (eMCCA) mechanism, for IEEE 802.11s-based wireless mesh networks. The current draft of IEEE 802.11s includes an optional medium access control (MAC), denoted as MCCA, which is designed to provide collision-free and guaranteed channel access during reserved periods. However, the MCCA mechanism fails to achieve the desired goal in the presence of contending non-MCCA nodes; this is because non-MCCA nodes are not aware of MCCA reservations and have equal access opportunities during reserved periods. We first present a probabilistic analysis that reveals the extent to which the performance of MCCA may be affected by contending non-MCCA nodes. We then propose eMCCA, which allows MCCA-enabled nodes to enjoy collision-free and guaranteed channel access during reserved periods by means of prioritized and preemptive access mechanisms. Finally, we evaluate the performance of eMCCA through extensive simulations under different network scenarios. The simulation results indicate that eMCCA outperforms other mechanisms in terms of success rate, network throughput, end-to-end delay, packet-loss rate, and mesh coordinated channel access opportunity-utilization.

Mobile Access Network Design (이동통신 액세스망 설계)

  • Kim, Hu-Gon;Paik, Chun-Hyun;Kwon, Jun-Hyuk;Chung, Yong-Joo
    • Korean Management Science Review
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    • v.24 no.2
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    • pp.127-142
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    • 2007
  • This study deals with the optimal design of mobile access network connecting base stations(BSs) and mobile switching centers(MSCs). Generally mobile operators constitute their access networks by leasing communication lines. Using the characteristic of leased line rate based on administration region, we build an optimization model for mobile access network design which has much smaller number of variables than the existing researches. And we develop a GUI based optimization tool integrating the well-known softwares such as MS EXCEL. MS VisualBasic, MS PowerPoint and Ip_solve, a freeware optimization software. Employing the current access network configuration of a Korean mobile carrier, this study using the optimization tool obtain an optimal solution for both single MSC access network and nation-wide access network. Each optimal access network achieves 7.45% and 9.49% save of lease rate, respectively. Considering the monthly charge and total amount of lease line rate, our optimization tool provides big amount of save in network operation cost. Besides the graphical representation of access networks makes the operator easily understand and compare current and optimal access networks.

A Role-driven Security and Access Control Model for Secured Business Process Management Systems

  • Won Jae-Kang;Kim Kwang-Hoon
    • The Journal of Information Systems
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    • v.14 no.3
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    • pp.1-8
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    • 2005
  • This paper formally defines a role-driven security and access control model of a business process in order eventually to provide a theoretical basis for realizing the secured business process management systems. That is, we propose a graphical representation and formal description of the mechanism that generates a set of role-driven security and access control models from a business process modeled by the information control net(ICN) modeling methodology that is a typical business process modeling approach for defining and specifying business processes. Based upon the mechanism, we are able to design and accomplish a secured business process management system that provides an unified resource access control mechanism of the business process management engine domain's and the application domain's. Finally, we strongly believe that the secured access control policies from the role-driven security and access control model can be easily transformed into the RBAC(Role-based Access Control) model that is a standardized security technology for computer and communications systems of commercial and civilian government organizations.

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Implementation of bluetooth LAN Access Point for the wireless Local access (근거리 무선 제어를 위한 Bluetooth LAN Access Point 구현)

  • Lee, Byeong-Woong;Oh, Won-Geun;Yoe, Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.5
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    • pp.676-683
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    • 2002
  • In this paper, LAN Access Point is realized by making out bluetooth protocol stack in Linux Kernel, porting Linux in an embeded system employed bluetooth module. Hardware for a general-purpose embeded system is designed and Linux Kernel is ported after deploying Bluetooth Module. Also, Boot loader for system booting and management is composed, and Kernel is modified to meet with the system. Finally, Ethernet devise driver is made out, and bluetooth protocol Stack and Lan Access Point are realized. The possibility of TCP/IP communication through LAN Access Point to PC employed Bluetooth module, which is considered as client, is evaluated. From the evaluation results, we can see that the performance in Telnet FTP, Web browsing through Bluetooth LAN Access Point is satisfactory.

A Study on Instructions for Access Points Representing Works and Expressions in RDA (RDA의 저작과 표현형의 접근점 규정에 관한 연구)

  • Doh, Tae-Hyeon
    • Journal of Korean Library and Information Science Society
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    • v.43 no.3
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    • pp.27-48
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    • 2012
  • This study analyzed guidelines and instructions for access points representing works and expressions in RDA. The preferred title for the work is used as the basis for constructing an authorized access point to represent a work or expression. If applicable, the authorized access point is constructed by combining the preferred title for the work to the authorized access point for the identity with principal responsibility for the work. The variant titles for the work are used as the basis for constructing variant access points to represent a work or expression. If the authorized access point is constructed by combining the preferred title for the work to the authorized access point for the identity responsible for the work, the variant access points are constructed by combining the variant titles for the work to the authorized access point, and by using only the preferred title for the work. Besides, RDA provides instructions to construct the controlled access points for special works like musical works, laws, religious works and others, but the general principles for these works are same as the above instructions. The authorized access points for works and expressions in RDA are almost same as the main entry headings in AACR2.

Management of the Access Control for a WebDAV-based Collaborative System (웹데브 기반 협업시스템에서의 접근 제어 관리)

  • Kim, Seong-Hune;Lee, Hong-Chang;Lee, Myung-Joon;Park, Yang-Su
    • Journal of Internet Computing and Services
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    • v.11 no.1
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    • pp.167-181
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    • 2010
  • WebDAV is an IETF standard protocol which supports asynchronous collaborative authoring on the Web. The WebDAV Access Control Protocol provides various methods of controlling the resources on a WebDAV server and their properties, helping high-level group activities to be performed through the WebDAV server. In this paper, to provide high level collaboration, we introduce a technique for managing access control over WebDAV resources through the WebDAV Access Control Protocol and describe the development of an access control manager for the CoSlide Collaborative system based on the technique. To provide users with the access control features in an easily understandable manner, the developed technique presents the privileges for performing WebDAV methods instead of the standard privileges in the WebDAV Access Control Protocol. In addition, we present the facility for detecting conflicts between new access privileges on resources and old access privileges on them. We applied the method-based access control management technique to the CoSlide collaborative system. The developed access control manager enables us to create group workspaces with flexible access control strategies for group members and resources.

Case Study of Usability Evaluation and Improvement Plan for Open Access Academic Publishing Support Interface (오픈액세스 학술출판 지원 인터페이스 사용성 평가 및 개선안 사례 연구)

  • Lee, Jeong-Mee;Hwang, Hyekyong
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.32 no.4
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    • pp.47-66
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    • 2021
  • The goal of this study is to find ways to improve the open access publication support service platform through the usability evaluation of the publishing manager interface among the AccessON journal repository interfaces, which is an open access publication support service platform. Various documents and cases related to open access publishing and usability evaluation in order to answer three research questions: collection of user experience responses of interface, extraction of issues and improvement points, and analysis and derivation of suggestions for other open access publication support service platforms. Responses to the experience of using the publishing manager interface were collected through surveys and focus group interviews. Combining this, it was possible to present the results of the usability evaluation of the AccessON journal repository interface through various numerical information. The results of the usability evaluation made it possible to propose issues and improvements to the AccessON journal repository manager interface, and finally, it was possible to derive suggestions for the open access academic publishing support service platform to be developed later.

A Study on the Performance of the Various Multiple Access for the Mobile Computer Network (이동 컴퓨터 통신망용 다중 엑세스 방식의 성능 연구)

  • 백지현;조동호;이영웅
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.7
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    • pp.641-655
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    • 1992
  • In this paper, the performance of the various multiple accesstechniques for the mobile computer network has been studied in the consideration of the characteristics. Of the mobile communication channel. In the case of the hidden node occurring, it could be seen that the performance of the code division multiple access(CDMA) technique. With simultaneous access function is better than that of the other packet access methods such as carrier sensed multiple access(CAMA). Busy tone mulitiple access(BTMA)and idle signal muitiple access(ISMA) in the view of the throuhtput and mean delay time. Also it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access(CSMA).etc when the fading effect or impulsive noise exists in the mobile channel. Especially in the case of the distributed mobile network. It has been shown that the receiver-transmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

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THE INFLUENCE OF DIFFERENT ACCESS CAVITY DESIGNS ON THE FRACTURE STRENGTH IN ENDODONTICALLY TREATED MANDIBULAR ANTERIOR TEETH (근관와동형태에 따른 근관치료된 하악절치의 파절강도)

  • Lee Young-Gyun;Shin Hye-Jin;Park Se-Hee;Cho Kyung-Mo;Kim Jin-Woo
    • Restorative Dentistry and Endodontics
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    • v.29 no.6
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    • pp.515-519
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    • 2004
  • Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOV A and the Scheffe test at the 95% confidence level. The results of this study were as follows: 1. The mean fracture strength decrease in following sequence Group 1 (4558.90{\;}\pm{\;}77.40{\;}N$), Group 2 ($494.07{\;}\pm{\;}123.98{\;}N) and Group 3 ($267.33{\;}\pm{\;}27.02{\;}N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.