• Journal of KIISE:Computing Practices and Letters
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• v.7 no.4
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• pp.336-349
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• 2001

Intelligent Network (IN) is an architectural framework for the rapid and uniform provision of advanced services. Therefore, Next-generation IN platform should support fast service handling, the dynamic adaptation of various services according to various requirements of users. In this paper, we design and implement the Service Control Point (SCP) that is based on the Internet environment. Especially, we consider the service flexibility, the dynamic distribution of service and propose a set of mechanisms to optimize the performance of this platform. This SCP consists of the platform kernel to control intemal operations, tbe service manager to control all of services, SLPI (Service Logic processing Program Instance) manager to manage each service, and SLPI to handle service interaction. In addition, we propose the Service Creation Environment (SCE) to create easily services on the implemented platfonn and show the example of Call Forwarding service operated on this platform.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.403-418
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• 2009

IP version 6 (IPv6) is a new If addressing scheme that has 128-bit address space. IPv6 is proposed to solve the address space problem of IP version 4 (IPv4) which has 32-bit address space. For a given IPv6 routing set, if a forwarding table is built using a trio structure, the trio has a lot more levels than that for IPv4. Hence, for IPv6 address lookup, the binary search on trio levels would be more appropriate and give better search performance than linear search on trio levels. This paper proposes a new IPv6 address lookup algorithm performing binary search on trio levels. The proposed algorithm uses a Bloom filter in pre-filtering levels which do not have matching nodes, and hence it reduces the number of off-chip memory accesses. Simulation has been performed using actual IPv6 routing sets, and the result shows that an IPv6 address lookup can be performed with 1-3 memory accesses in average for a routing data set with 1096 prefixes.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.57-67
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• 2015

A large amount of work has been done in the areas of routing, MAC, QoS, capacity, location service, cooperative communication, fault tolerance, mobility models and various applications of mesh networks thanks to their merits of cost-effective way of deployment and flexibility in extending wireline services. Although multi-path routing protocols have been proposed to be used to provide QoS and fault-tolerance, there has not been any significant results discussed that support both in the literature to our best knowledge as they are often required in military and public safety applications. In this paper, we present a novel routing protocol for a mesh network based on the OFDM-TDMA collision-free MAC that discovers and maintains multiple paths that allows retransmitting and forwarding packets that have been blocked due to a link failure using an alternative next-hop node such that the delay-capacity tradeoff is reduced and the reliability is enhanced. Simulation results show that the proposed protocol performs well in terms of both the QoS and delivery ratio.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.10-16
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• 2016

For higher reliability against a link failure of a control network in railway vehicles, a recovery mechanism is needed. We introduce a problem that, when a link failure occurs in a ring-topology control network, a node may experience a significant increase of transmission delay depending on its relative position within the network. We then propose two mechanisms to solve this problem: (1) differentiating and prioritizing node traffic in forwarding; and (2) switching some nodes to a backup bus-topology network. Our simulation study shows that, while the first mechanism achieves a limited gain by only compensating queuing delay, the second one gets a sufficient gain which is impacted by the number of nodes switched to the bus network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1505-1510
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• 2008

In large-scale wireless sensor networks, the deployed nodes cannot be replaced or recharged after first deployment. Also, dead nodes maγ lead to the partition of whole networks. While performing data dissemination under a battery power constraint, energy efficiency is a key design factor of routing protocol. As a solution for the efficient data dissemination, in this paper, we propose a protocol namely Hierarchical Data Dissemination (HDD) which provides scalable and efficient data delivery to multiple sources and mobile sinks. HDD uses the facts that sink nodes are central gathering Points and source-centric data forwarding paths are constructed and it is maintained with two-tier communications. The performance of HDD is compared with TTDD about the energy consumption, data delivery time and data success ration. The extensive simulation results show that HDD Routing Protocol outperforms TIDD by more than $1.5{\sim}3times$ on energy consumption.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.56-65
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• 2007

Existing application systems of enterprises can process and collect a lot of information within enterprises, but it could be difficult to share validated information with partners and other system in the process of contacting to other legacy systems required in cooperation environment. For solving these problems, EAI systems are introduced in cooperation environment so that data sharing and integration can be achieved. The integration based on EAI is not limited to particular business system but all systems of an enterprise so that standard of suitable metadata level is needed for forwarding consistently between each business of systems. Therefore this paper maintains consistency of data sharing and integrating among legacy systems in cooperative environment for proposing message exchanging based on bridge XMDR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.993-999
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• 2021

Recently, many studies on VNDN technology have been conducted to graft Named Data Networking (NDN) into VANET as a core network technology. VNDN can use the content name to deliver various infotainment application content data through name-based forwarding. When VNDN is used as a communication technology for infotainment applications in connected vehicles, it is possible to realize data-centric networking technology in which data is the subject of communication. It can overcome the limitations of connected vehicle infotainment application service technology based on the host-centric current Internet, such as security attack/hacking, performance degradation in long-distance data transmission, frequent data cut-off. In this paper, we present the main functions provided by VNDN technology, and systematically analyze and organize the issues necessary to realize infotainment application services for connected vehicles in the VNDN environment. Based on this, it can be utilized as basic information necessary to establish infotainment application requirements in VNDN environment.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.1
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• pp.53-75
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• 2019

This study has examined the policy status of the specialized libraries and analyzed the status of curation services of libraries and similar institutions and portals, and proposed policy directions for the curation services provision of the specialized libraries. As for the results of this study, first, curation information is collected and selected through the participation of various curators, and the curation information is regularly updated on the websites and online gateways toward maximizing the perception of the book collections in place and the use of collections. Second, the scope of the specialized libraries' curation services are diversified, such as research support services, one-on-one customized curation services, and book curation. Third, digital curation services are constructed in connection with specialized themes. Fourth, beacon is installed inside, and based on the information received from the information forwarding media, individualized user services are provided via such data as the scope of movement of the users and the time entailed for dwelling in a space.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.711-732
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• 2019

Many unmanned aerial vehicle (UAV) applications have been employed for performing data collection in facilitating tasks such as surveillance and monitoring objectives in remote and dangerous environments. In light of the fact that most of the existing UAV relaying applications operate in conventional half-duplex (HD) mode, a full-duplex (FD) based UAV relay aided wireless network is investigated, in which the UAV relay helps forwarding information from the source (S) node to the destination (D). Since the activated UAV relays are always floating and flying in the air, its channel state information (CSI) as well as channel capacity is a time-variant parameter. Considering decode-and-forward (DF) relaying protocol in UAV relays, the cooperative relaying channel capacity is constrained by the relatively weaker one (i.e. in terms of signal-to-noise ratio (SNR) or signal-to-interference-plus-noise ratio (SINR)) between S-to-relay and relay-to-D links. The channel capacity can be optimized by adaptively optimizing the transmit power of S and/or UAV relay. Furthermore, a hybrid HD/FD mode is enabled in the proposed UAV relays for adaptively optimizing the channel utilization subject to the instantaneous CSI and/or remaining self-interference (SI) levels. Numerical results show that the channel capacity of the proposed UAV relay aided wireless networks can be maximized by adaptively responding to the influence of various real-time factors.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.83-91
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• 2008

IISO/IEC 9594-8 defines the public key framework and attribute certificate framework. Attribute certificate framework deals with privilege management infrastructure(PMI). In PMI, for privilege management using attribute certificates, role assignment certificates and role specification certificates are used to assign and specify privileges independently. Role specification certificates includes privilege specifications and the details far privilege management of network environments. Privilege management of unreliable network environment tries to enhance the reliability and efficiency of privilege information transmission forwarding over unreliable routes in the presence of potentially faulty nodes and edges. Each node forms a role specification tree based on role specification relationship data collected from the network. In this paper privilege management cost with the role specification certificates tree structure is evaluated trying to reduce the overhead incurred by role creation and modification of privileges. The multicasting of packets are used for scalability. We establish management cost model taking into account the packet loss and node reliability which continuously join and leave for network. We present quantitative results which demonstrate the effectiveness of the proposed privilege management scheme.