• Journal of Information Technology Services
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• v.8 no.3
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• pp.171-184
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• 2009

Since the development of the Distributed Hash Tables (DHTs), the distributed lookup services are one of the hot topics in the networking area. The main reason of this popularity is the simplicity of the lookup structure. However, the simple key based search mechanism makes the so called "keyword" based search difficult if not impossible. Thus, the applicability of the DHTs is limited to certain areas. In this paper. we find that DHTs can be used as the ubiquitous sensor network (USN) metadata lookup service across a large number of sensor networks. The popularity of the Ubiquitous Sensor Network has motivated the development of the USN middleware services for the sensor networks. One of the key functionalities of the USN middleware service is the lookup of the USN metadata, by which users get various information about the sensor network such as the type of the sensor networks and/or nodes, the residual of the batteries, the type of the sensor nodes. Traditional distributed hash table based lookup systems are good for one sensor network. However, as the number of sensor network increases, the need to integrate the lookup services of many autonomous sensor networks so that they can provide the users an integrated view of the entire sensor network. In this paper, we provide a hybrid lookup model, in which the autonomous lookup services are combined together and provide seamless services across the boundary of a single lookup services. We show that the hybrid model can provide far better lookup performance than a single lookup system.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.2
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• pp.57-62
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• 2014

In order to provide real-time multimedia streaming service, a lot of system resources and network bandwidth required. Thus each computer is any computer other equivalent has the ability to act as a client and a server Peer-to-Peer(P2P) architecture with much interest. In this paper, techniques of P2P content that requires a user to efficiently retrieve the desired time in the streaming service have placed the focus of the research techniques. In a number present in the P2P contents, the user requests to find out the desired amount of time the content streaming services in order to provide seamless lookup latency contents search algorithm to minimize the study. P2P based smart network system and the structure of the super-node and the peer node is composed of super-gateway. Smart network system architecture proposed by performing a content search algorithm. The user requests a desired content, the service can be retrieved within the provided the flexibility.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.1
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• pp.493-519
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• 2021

The purpose of this study is to propose a plan to implement the comprehensive linking system centered on identifiers in order to provide seamless academic information services to researchers. To achieve this goal, interviews were conducted with 17 researchers from five centers and one secretariat belonging to KISTI. The contents of the interview are about the establishment and management status of the identifier of the academic information service DB. As a result of the interview, it was found that the identification rate for identifiers such as KOI was high in the case of domestic articles DB, but the identification rate for global identifiers such as ORCID was low in the case of foreign articles DB except for DOI. To solve this problem, this study proposes the council for joint use of a comprehensive linking system to build the comprehensive linking system model centered on identifiers. The joint use council will be organized around domestic academic information distribution institutions, and the council is expected to discover and implement new services through ID linkage by collecting foreign identifiers.

• Journal of KIISE:Information Networking
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• v.33 no.3
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• pp.218-230
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• 2006

The enterprise service network is composed of internet, intranet and DMZ. The design rationale of Mobile IP is providing of seamless mobility transparency without regarding to the type of network topology and services. However, Mobile IP specification does not include the mobility support in case of using VPN environment and define the access scenarios to get into the VPN intranet without disturbing existing security policy. In this paper, we propose an authentication method using AAA infrastructure and keying material exchange to enable an user in internet to be able to access the intranet through the VPN gateway. Finally, performance analysis for the proposed scheme is provided.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.883-887
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• 2011

Location-based service (LBS) is becoming an important part of the information technology (IT) business. Localization is a core technology for LBS because LBS is based on the position of each device or user. In case of outdoor, GPS - which is used to determine the position of a moving user - is the dominant technology. As satellite signal cannot reach indoor, GPS cannot be used in indoor environment. Therefore, research and study about indoor localization technology, which has the same accuracy as an outdoor GPS, is needed for "seamless LBS". For indoor localization, we consider the IEEE802.11 WLAN environment. Generally, received signal strength indicator (RSSI) is used to obtain a specific position of the user under the WLAN environment. RSSI has a characteristic that is decreased over distance. To use RSSI at indoor localization, a mathematical model of RSSI, which reflects its characteristic, is used. However, this RSSI of the mathematical model is different from a real RSSI, which, in reality, has a sensitive parameter that is much affected by the propagation environment. This difference causes the occurrence of localization error. Thus, it is necessary to set a proper RSSI model in order to obtain an accurate localization result. We propose a method in which the parameters of the propagation environment are determined using only RSSI measurements obtained during localization.

• Journal of the Korean Society for information Management
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• v.24 no.1 s.63
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• pp.75-101
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• 2007

The current technological revolution pushes forward the innovation in the library information systems. This study proposes functional requirements and an architectural reference model of Semantic Library, recognized as a prototype of next-generation library information systems, that is a seamless convergence of the library information systems and the Internet technologies. Semantic Library can realize semantic interoperability and integration based on ontology and metadata, and also renovate information services for users with openness, sharing, participation and collaboration. Semantic Library will be effectively implemented by means of service-oriented architecture and the logical structure of FRBR. In this study, a reference model of Semantic Library consisting of 6 horizontal layers and 3 vertical elements is presented as a next-generation model of library information systems.

• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.183-188
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• 2003

The $4^{th}$ generation mobile communications, through several radio access networks such as WLAN, Bluetooth, UMTS, GPRS, CDMA 1X, and IMT-2000 in the same area offering different type of coverage, will support interactive multimedia services in additions to wider bandwidths, higher bit rates, and service portability. Regardless of various radio access networks, they will also support robust security mechanisms, as well as seamless mobility and common authentication. In this paper, we give an overview of WLAN security and examine its security problems. We also explain the enhanced security schemes, such as port-based authentication, EAP, and IEEE 802.1X. For secure wireless communications, several possible security solutions are offered and evaluated in various respects to improve WLAN security. This paper will make a contribution to provide more secure wireless communications to cellular operators embracing WLAN technology as a means to generate new revenues based on data services.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.54-62
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• 2011

This paper proposes both global and local mobility management (MM) scheme improved from Multi Protocol Label Switching (MPLS)-based Mobility Management scheme (MPLS-MOB) for seamless service in Next Generation Network (NGN). The proposed scheme adds local MM on the existing MPLS-MOB which supports global MM by processing handover signaling by 2.5 layer switching via Label Switch Path (LSP) of MPLS. We numerically analyze and verify that the proposed scheme has lower handover latency time than the existing ones, such as micro-MM methods using MPLS as well as MIP and an interworking scenario between PMIP and MIP.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.99-104
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• 2014

In this paper, the authors propose a multi-transmission mechanism of heterogeneous network environment which is applicable to the SMART screen services over wire and wireless convergence network. This paper presents study results including a SMART screen handover algorithm among multiple collaborative devices under wire and wireless convergence and heterogeneous network environment, and a service operation and management system and a NAS system providing SMART services of AV streaming and contents files. These validate implementation feasibility of a call processing engine for seamless SMART screen collaborative services, AV streaming services and SMART screen collaborative services supporting mobility management and multiple users/multiple streams.

• Journal of Communications and Networks
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• v.6 no.3
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• pp.245-257
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• 2004

Driven by the growing number of the mobile subscribers, efficient channel resource management plays a key role for provisioning multimedia service in the next generation personal communication systems. To reuse limited channel resources, diminishing the coverage areas of cells seems to be the ultimate solution. Thus, however, causes more handover events. To provide seamless connection environment for mobile terminals and applications, this article presents a novel handover scheme called the intelligent channel reservation (ICR) scheme, which exploits the location prediction technologies to accurately reserve channel resources for handover connections. Considering the fact that each mobile terminal has its individual mobility characteristic, the ICR scheme utilizes a channel reserving notification procedure (CRNP) to collect adequate parameters for predicting the future location of individual mobile terminals. These parameters will be utilized by the handover prediction function to estimate the expected handover blocking rate and the expected number of idle channels. Based on the handover prediction estimations, a cost function for calculating the damages from blocking the handover connections and idling channel resources, and a corresponding algorithm for minimizing the cost function are proposed. In addition, a guard channel decision maker (GCDM) determines the appropriate number of guard channels. The experimental results show that the ICR scheme does reduce the handover-blocking rate while keeping the number of idle channels small.