• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2047-2050
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• 2002

At present, many applications independently provide access control for their own resources, for example Web, Databases and Operating Systems, etc. Such independent access control systems result in multiple access control configurations each of which deals with the access control in its own application context. Since those multiple configurations are operated in isolation, and maintained by possibly different administrators, they are likely to be incoherent. In this paper, we propose a logical specification to reason about multiple access control configurations. Our specification can be used to detect the incoherence in multiple configurations. Furthermore, it of offers many kinds of policies for multiple configurations that can capture several kinds of requirements for multiple access control systems.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.639-641
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• 2002

In this paper, we proposed the multiple access control of RS232C Serial Communications protocol using collision sense method. The communications wires of data transmission and reception are tied together through the buffer each to connect to the multiple communication channels. The hardware interface and control program are designed to build the prototype system and the experimental multiple access communications network is built by multiple PC systems and the transfer completion rate results are shown.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.291-295
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• 2004

As a large quantity of information is presented in XML format on the web, there are increasing demands for XML security. Until now research on XML security has been focused on the security of data network using digital signature and encryption technology. As XML data become extensive and complex however XML security comes to involve not only network security but also managerial security. But XML encryption support simple network security. So it cannot support multiple users and multiple access control policy. In this paper, we propose an integration method of encryption and access control policy for securing XML documents. This methodology can support multiple authorization of multiple users with integrating access control. And this can reduce the cost of the existing complicated access evaluation process of access control by using pre-processing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1394-1401
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• 2007

Secure access control is a hot issue of large-scale organizations or information systems, because they have numerous users and information objects. In many cases, system developers should implement an access control module as a part of application. This way induces difficult modification of the module and repeated implementation for new applications. In this paper we implement a Java API library for access control to support system developers who use Java. They can easily build up access control module using our library. Our library supports typical access control models, and it can offer new types of access control. Furthermore, it is able to run multiple access control models at the same time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.1
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• pp.3-15
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• 2005

As a large quantity of information is presented in XML format on the web, there are increasing demands for XML security. Research area or n security is about Encryption Digital signature, Key management and Access control. until now research on U security has been focused on the security of data network using digital signature and encryption technology. As XML data become extensive and complex XML security comes to involve not only network security but also managerial security. Managerial security is guaranteed through access control. But XML Encryption supports simple network security. So it can't support multiple users and multiple access control policies. In this paper, we propose an integration method of encryption and access control policy for securing XML documents. This methodology can supper multiple authorizations of multiple users with integrating access control. And this can reduce the cost of evaluation process of the existing complicated access authorization with pre-processing.

• Journal of Communications and Networks
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• v.13 no.1
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• pp.43-49
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• 2011

In this paper, a new medium access control (MAC) protocol entitled three-phase multiple access with continual contention resolution (TPMA-CCR) is proposed for wireless multi-hop ad hoc networks. This work is motivated by the previously known three-phase multiple access (TPMA) scheme of Hou and Tsai [2] which is the suitable MAC protocol for clustering multi-hop ad hoc networks owing to its beneficial attributes such as easy collision detectible, anonymous acknowledgment (ACK), and simple signaling format for the broadcast-natured networks. The new TPMA-CCR is designed to let all contending nodes participate in contentions for a medium access more aggressively than the original TPMA and with continual resolving procedures as well. Through the systematical performance analysis of the suggested protocol, it is also shown that the maximum throughput of the new protocol is not only superior to the original TPMA, but also improves on the conventional slotted carrier sense multiple access (CSMA) under certain circumstances. Thus, in terms of performance, TPMA-CCR can provide an attractive alternative to other contention-based MAC protocols for multi-hop ad hoc networks.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.137-142
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• 2006

As a large quantity of information is represented in XML format on the web, there are increasing demands for XML security. Until now research on XML security has been focused on the security of data network using digital signature and encryption technology. As XML data become extensive and complex, however, XML security comes to involve not only network security but also managerial security. But XML encryption support only simple network security. So it cannot support multiple users and multiple access control policy. In this paper, we propose an integration method of encryption and access control policy for securing XML documents. This methodology can support multiple authorization of multiple users with integrating access control.

• Journal of the Korea Society of Computer and Information
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• v.29 no.9
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• pp.115-123
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• 2024

This paper proposes a method to reduce the delay time caused by control message conflicts in VADAMA (Virtual Allocation Demand Assigned Multiple Access) technology, which is a virtual allocation based on-demand multiple access technology in MF-TDMA (Multi-Frequency Time Division Multiple Access) satellite network. Traditionally, satellite networks have had the problem that all network transmissions have long delay times due to control messages. In this study, in order to improve the delay time caused by terminal control message conflicts in VADAMA technology, the concept of virtual allocation is used to reduce the delay time. VADAMA-PTR (VADAMA Periodic Transmission) divides all terminals into subnets and transmits control. The method is proposed, and the performance analysis of the existing DAMA technology, delay time and data processing rate is performed using Matlab. The results show that the performance is improved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.1
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• pp.105-111
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• 1997

This Paper Proposes a new efficient system design strategies for the acoustic-based underwater multiple modem and media access control protocol. The system aims to establish the acoustic-based communication network of an underwater vehicles for deep sea mining, which ensures a certain level of maximum throughput regardless of the propagation delay of acoustic and allows fast data transmission through the acoustic-based multiple channel. A media access control protocol for integrated communication network and it's acoustic-based communication modems that allows 'peer-to-peer' communication between a surface mining plant multiple underwater system is designed, and the proposed media access control protocol is implemented for its verification. Furthermore, a proposed design strategies which make it possible to control the multiple vehicle for an underwater mining is presented in this paper.

• ETRI Journal
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• v.23 no.2
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• pp.52-60
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• 2001

In this paper, a medium access control protocol is proposed for integrated voice and data services in wireless local networks. Uplink channels for the proposed protocol are composed of time slots with multiple spreading codes per slot based on slotted code division multiple access (CDMA) systems. The proposed protocol uses spreading code sensing and reservation schemes. This protocol gives higher access priority to delay-sensitive voice traffic than to data traffic. The voice terminal reserves an available spreading code to transmit multiple voice packets during a talkspurt. On the other hand, the data terminal transmits a packet without making a reservation over one of the available spreading codes that are not used by voice terminals. In this protocol, voice packets do not come into collision with data packets. The numerical results show that this protocol can increase the system capacity for voice service by applying the reservation scheme. The performance for data traffic will decrease in the case of high voice traffic load because of its low access priority. But it shows that the data traffic performance can be increased in proportion to the number of spreading codes.