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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 31, Issue 12C - Dec 2006
Volume 31, Issue 12B - Dec 2006
Volume 31, Issue 12A - Dec 2006
Volume 31, Issue 11C - Nov 2006
Volume 31, Issue 11B - Nov 2006
Volume 31, Issue 11A - Nov 2006
Volume 31, Issue 10C - Oct 2006
Volume 31, Issue 10B - Oct 2006
Volume 31, Issue 10A - Oct 2006
Volume 31, Issue 9C - Sep 2006
Volume 31, Issue 9B - Sep 2006
Volume 31, Issue 9A - Sep 2006
Volume 31, Issue 8C - Aug 2006
Volume 31, Issue 8B - Aug 2006
Volume 31, Issue 8A - Aug 2006
Volume 31, Issue 7C - Jul 2006
Volume 31, Issue 7B - Jul 2006
Volume 31, Issue 7A - Jul 2006
Volume 31, Issue 6C - Jun 2006
Volume 31, Issue 6B - Jun 2006
Volume 31, Issue 6A - Jun 2006
Volume 31, Issue 5C - May 2006
Volume 31, Issue 5B - May 2006
Volume 31, Issue 5A - May 2006
Volume 31, Issue 4C - Apr 2006
Volume 31, Issue 4B - Apr 2006
Volume 31, Issue 4A - Apr 2006
Volume 31, Issue 3C - Mar 2006
Volume 31, Issue 3B - Mar 2006
Volume 31, Issue 3A - Mar 2006
Volume 31, Issue 2C - Feb 2006
Volume 31, Issue 2B - Feb 2006
Volume 31, Issue 2A - Feb 2006
Volume 31, Issue 1C - Jan 2006
Volume 31, Issue 1B - Jan 2006
Volume 31, Issue 1A - Jan 2006
Selecting the target year
Performance Analysis of Random Early Dropping Effect at an Edge Router for TCP Fairness of DiffServ Assured Service
Hur Kyeong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 255~269
The differentiated services(DiffServ) architecture provides packet level service differentiation through the simple and predefined Per-Hop Behaviors(PHBs). The Assured Forwarding(AF) PHB proposed as the assured services uses the RED-in/out(RIO) approach to ensusre the expected capacity specified by the service profile. However, the AF PHB fails to give good QoS and fairness to the TCP flows. This is because OUT(out- of-profile) packet droppings at the RIO buffer are unfair and sporadic during only network congestion while the TCP's congestion control algorithm works with a different round trip time(RTT). In this paper, we propose an Adaptive Regulating Drop(ARD) marker, as a novel dropping strategy at the ingressive edge router, to improve TCP fairness in assured services without a decrease in the link utilization. To drop packets pertinently, the ARD marker adaptively changes a Temporary Permitted Rate(TPR) for aggregate TCP flows. To reduce the excessive use of greedy TCP flows by notifying droppings of their IN packets constantly to them without a decrease in the link utilization, according to the TPR, the ARD marker performs random early fair remarking and dropping of their excessive IN packets at the aggregate flow level. Thus, the throughput of a TCP flow no more depends on only the sporadic and unfair OUT packet droppings at the RIO buffer in the core router. Then, the ARD marker regulates the packet transmission rate of each TCP flow to the contract rate by increasing TCP fairness, without a decrease in the link utilization.
Markov CAC model in Wireless Mobile Networks Using AMC
Kwon Eun-Hyun ; Park Hyo-Soon ; Lee Jai-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 270~277
In the wireless adaptive modulation and coding(AMC) systems, the modulation type of user's connection can be changed dynamically. and the ongoing connection might fail due to the change of modulation. In this paper, we approach the AMC-induced CAC problem by focusing on the guaranteed connection. Three kinds of calls, new, handoff, and modulation-changed calls, are considered. We propose a modified guard channel CAC scheme that allows the modulation-changed and handoff calls to use the guard channel. Then we analyze a Markov model for the CAC scheme with long-term AMC in mind. According to the simulation results, the proposed approach reduces the call dropping probability for modulation-changed calls, which suggests the threshold of guard channels can be determined based on the proposed approach.
A Study on Autonomous Driving Mobile Robot by Using Fuzzy Algorith
Seo Hyun-Jae ; Lim Young-Do ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 278~284
In thispaper, we designed a intelligent autonomous driving robot by using Fuzzy algorithm. The object of designed robot is recognition of obstacle, avoidance of obstacle and safe arrival. We append a suspension system to auxiliary wheel for improvement in stability and movement. The designed robot can arrive at destination where is wanted to go by the old and the weak and the handicapped at indoor hospital and building.
Implementation of Non-SQL Data Server Framework Applying Web Tier Object Modeling
Kwon Ki-Hyeon ; Cheon Sang-Ho ; Choi Hyung-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 285~290
Various aspects should be taken into account while developing a distributed architecture based on a multi-tier model or an enterprise architecture. Among those, the separation of role between page designer and page developer, defining entity which is used for database connection and transaction processing are very much important. In this paper, we presented DONSL(Data Server of Non SQL query) architecture to solve these problems applying web tier object modelling. This architecture solves the above problems by simplifying tiers coupling and removing DAO(Data Access Object) and entity from programming logic. We concentrate upon these three parts. One is about how to develop the DAO not concerning the entity modification, another is automatic transaction processing technique including SQL generation and the other is how to use the AET/MET(Automated/Manual Execute d Transaction) effectively.
HIMIPv6: An Efficient IP Mobility Management Protocol for Broadband Wireless Networks
Jeong Hyeon-Gu ; Kim Young-Tak ; Maeng Seung-Ryoul ; Chae Young-Su ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 291~302
With the increasing deployment of mobile devices and the advent of broadband wireless access systems such as WiBro, WiMAX, and HSDPA, an efficient IP mobility management protocol becomes one of the most important technical issues for the successful deployment of the broadband wireless data networking service. IETF has proposed the Mobile IPv6(MIPv6) as the basic mobilitymanagement protocol for IPv6 networks. To enhance the performance of the basic MIPv6, researchers have been actively working on HMIPv6 and FMIPv6 protocols. In this paper, we propose a new mobility management protocol, HIMIPv6 (Highly Integrated MIPv6), which tightly integrates the hierarchical mobility management mechanism of the HMIPv6 and the proactive handover support of the FMIPv6 to enhance the handover performance especially for the cellular networking environment with high frequent handover activities. We have performed extensive simulation study using ns-2 and the results show that the proposed HIMIPv6 outperforms MIPv6, FMIPv6 and HMIPv6 in terms of signaling overhead, service interruption and packet lost during handovers.
Reliable Data Aggregation Protocol for Wireless Sensor Networks
Shin Sang-Ryul ; Lee Jong-Il ; Baek Jang-Woon ; Seo Dae-Wha ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 303~310
In sensor network environments, a sensor node has a limited power because of their resource constraints. Therefore it is important to efficiently use its power in sensor networks. Power consumption of sensor node is closely related to its amount of transmission data. So, we need to reduce the transmission data in order to minimize the power consumption. And sensor networks are inherently unreliable because radio transmission can fail, node can move, and so on. In this paper, we propose the reliable data aggregation protocol in order to these problems. This protocol performs the routing and the query inserting process at the same time to minimize the packet loss caused by network changes. And, this protocol removes the unnecessary routing caused by the periodic routing without query. Additionally, we suggest the countermeasure algorithm against the frequent errors in sensor networks.
Update Propagation of Replicated Data in a Peer-to-Peer Environment
Choi Min-Young ; Cho Haeng-Rae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 311~322
Peer-to-peer (P2P) systems have become a popular medium through which to share huge amounts of data. On the basis of network topology, P2P systems are divided into three types: centralized, structured distribution, unstructured distribution. Unstructured P2P systems such as Gnutella are novel in the sense that they are extensible and reliable. However, as the number of nodes increases, unstructured P2P systems would suffer from the high complexity of search operations that have to scan the network to find the required data items. Efficient replication of data items can reduce the complexity, but it introduces another problem of maintaining consistency among replicated data items when each data item could be updated. In this paper, we propose a new update propagation algorithm that propagates an updated data item to all of its replica. The proposed algorithm can reduce the message transfer overhead by adopting the notion of timestamp and hybrid push/pull messaging.
Performance Evaluation of the Probability based MAC Protocol for Fair Transmission in WDM Metro Ring
So Won-Ho ; Kim Young-Chon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 323~332
In this paper, we consider a WDM based metro ring connecting broadband access networks by using FT-TR (Fixed Transmitter-Tunable Receiver) type access nodes and a new MAC protocol for fair transmission is proposed. The basic channel access scheme is CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) and the transferred optical slot is changed to be empty slot by SS(Source-Stripping) which drops a packet from ring-rotated slot. This empty slot can be either used to send head-of-line packet in buffer or transmitted to next access node. In former cases, there is the improvement of network throughput, but latter case leads unfairness problem of transmission. Thus the proposed MAC protocol exploits the advantages form tow cases. It gives downstream access nodes chance to use empty slots and limits the unconditional usage of empty slots at upstream access nodes with probability as called p-Persistent MAC protocol. We use a numerical analysis to evaluate bandwidth efficiency and maximum node throughput and compares simulation results in terms of node throughput, fairness factor, transfer delay depending on probability. Under two different FT-TR type architectures for metro ring network the proposed MAC protocol is evaluated and compared.
BU-Chord Mechanism for Reliable P2P File Sharing over MANET
Jeong Hong-Jong ; Song Jeom-Ki ; Kim Dong-Kyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 333~343
MANET and P2P applications have a common nature that they don't have any fixed infrastructures that might maintain network topologies. With such common characteristics, a P2P application can be a killer application over MANET. Due to absence of reliable node which serves indexing services in MANET, fully distributed P2P applications are more suitable for MANET. By using DHT like Chord, we can save network bandwidth and avoid a point of failure of a directory server. However, since MANET allows nodes to depart from network freely, P2P file sharing applications using Chord lookup protocol should address how to recover the keys stored at the departed node. In this paper, we propose BU-Chord in order to detect and recover the departure of nodes by creating and storing backup file information in distributed manner. Our BU-Chord shows off better performance than existing Chord especially in case of high departure rate of nodes.
Policy-based Resource Management for QoS Support in Cellular Networks
Choi Sung-Gu ; Jun Kyung-Koo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 344~348
This paper proposes a QoS policy for cellular networks which support the policy based network management scheme. The policy exploits the existing underlying DiffServ mechanism and the priority-based packet scheduler in order to provide the packets with different handling priority depending on their belonging traffic classes. The simulation results reveals the effectiveness of the proposed policy under the network congestion; it shows that the goodput of the real-time traffic is not affected at all in spite of the surge of the non real-time traffic.
Policy-based End-to-End QoS Provision for 3G Networks Using DiffServ-aware MPLS
Choi Sung-Gu ; Jun Kyung-Koo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 349~354
In 3G networks interworking with external IP-based networks, provision of end-to-end QoS to packet-based services is a critical issue. In this paper, we propose DiffServ-aware Multiple Protocol Label Switching(MPLS) as a new policy enforcement means. With the adoption of the proposed DiffServ-aware MPLS, it is feasible to provide differentiated QoS provision with the help of DiffServ as well as to improve network utilization by using multiple paths based on MPLS. We verify the effectiveness of our proposed policy enforcement means through a simulation in which realtime traffic and non-realtime traffic are served together.
An Analysis of the Required Factors for Universal Service of Mobile Telecommunication Service in Korea - focusing on institutional aspects-
Ahn Ji-Young ; Choi Sung-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 4B, 2006, Pages 355~363
A rapidly increasing demand of voice and data through mobile telecommunication service and the development of technologies related with the service are sufficiently said to make the service become an indispensible communicating means, not just selective one. However, in the other side of the generalizing of mobile telecommunication service, there is said to be a worsening situation of unbalanced benefits due to the problem of information difference between the non. The more advanced mobile telecommunication service proceeds, the more deepens the problem, and it is generally known that the problem cannot be solved by the ability of free market itself as seen in the wired telecommunication market. Therefore, we need to set up a systematic policy of mobile telecommunication service for solving this problem, and also think over whether to include the service within the range of universal service. In this study, we examine the required factors for including the service within the range of universal service, and analyze the validity of the including in the view point of institutional aspects.