• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.25-34
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• 2006

Previous binding update protocols for Mobile IPv6 repeats the same protocol each time a mobile node moves to a foreign link Moreover, mobile nodes repeats the same protocol whenever the lifetime of the current binding update expires. To improve the efficiency of binding updates, we Propose a ticket-based binding update protocol for MIPv6. Our protocol minimizes the binding update cost using a ticket issued by the corresponding node. We have analyzed our protocol security against the security requirements of MIPv6 and existing attacks. Furthermore, we have also compared our protocol against previous binding update protocols.

• Journal of Internet Computing and Services
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• v.2 no.5
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• pp.71-79
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• 2001

Replication in distributed databases is to improve efficiency, availability, and autonomy, But applying the strict consistency in real systems is very difficult. In this paper, I introduce a hybrid protocol permitting group update through eager update propagation and weakening consistency through lazy update, This protocol manages replica version number for the group update consistency and generates partially ordered replica spanning tree for the serializability of lazy update transactions. It preserves weak consistency by combining synchronous and asynchronous update mechanism. Study of performance analysis for the efficiency of the protocol be included in next paper.

• Journal of Korean Library and Information Science Society
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• v.40 no.3
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• pp.317-336
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• 2009

Several protocols have been developed to efficiently utilize a great number of distributed resources. This paper investigated the background, operations and elements of SRU and SRU Record Update protocol, compared them with other protocols, and reviewed their implementation cases. The purpose of this pager is to broaden the understanding of the two new standards and to provide a practical guide to ensure their interoperability for libraries and information service centers which want to expose their own contents and to access to external resources.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2245-2252
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• 1999

Since DSM provides a user a simple shared memory abstraction, the user does not have to be concerned with data movement between hosts. Each node in DSM systems has processor, memory, and connection to a network. Memory is divided into pages, and a page can have multiple copies in different nodes. To maintain data consistency between nodes, two conventional protocols are used : write-update protocol and invalidate protocol. The performance of these protocols depends on the system parameters and the memory access patterns. for adapting to memory access patterns, competitive update protocol updates those copies of a page that are expected to be used in the near future, while selectively invalidating other copies. We present weighted competitive update protocols that consider different communication bandwidth for each connection a of two nodes. Test result by simulation show that the weighted competitive update protocol improves performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.115-124
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• 2005

We propose a new binding update(BU) protocol between mobile node(CN) and correspondent node(CN) for the purpose of preventing redirect attacks and DoS attacks observed from the existing BU protocols and enhancing the efficiency of the BU protocol. Home agent plays a role of both authentication server validating BU message and session key distribution center for MN and CN. Also propose the stateless Diffie-Hellman key agreement based on cryptographically generated address (CGA). Suity of our proposed Protocol is analyzed and compared with other protocols. The proposed protocol is more efficient than previous schemes in terms of the number of message flows and computation overhead and is secure against both redirect and DoS attacks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4977-4996
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• 2016

The existence of excessively large and too filled network buffers, known as bufferbloat, has recently gained attention as a major performance problem for delay-sensitive applications. Researchers have made three types of suggestions to solve the bufferbloat problem. One is End to End (E2E) congestion control, second is deployment of Active Queue Management (AQM) techniques and third is the combination of above two. However, these solutions either seem impractical or could not obtain good bandwidth utilization. In this paper, we propose a Transmission Control Protocol（TCP）delayed window update mechanism which uses a congestion detection approach to predict the congestion level of networks. When detecting the network congestion is coming, a delayed window update control strategy is adopted to maintain good protocol performance. If the network is non-congested, the mechanism stops work and congestion window is updated based on the original protocol. The simulation experiments are conducted on both high bandwidth and long delay scenario and low bandwidth and short delay scenario. Experiment results show that TCP delayed window update mechanism can effectively improve the performance of the original protocol, decreasing packet losses and queuing delay while guaranteeing transmission efficiency of the whole network. In addition, it can perform good fairness and TCP friendliness.

• The KIPS Transactions:PartD
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• v.9D no.1
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• pp.11-20
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• 2002

We propose a new concurrency control algorithm for enhancing the degree of parallelism of the transactions in fully replicated databases designed to improve the availability and the reliability. The update transactions can be logically decomposed of a read-only transaction and a write-only transaction. In our algorithm, a set of read operations of an update transaction is treated as a read-only transaction and the read-only transaction reads data items in the site to which it is submitted. And a set of write operations of the update transaction is treated as a write-only transaction and it is submitted to all corresponding sites after the update transaction has been completed. By using the proposed update protocol, all write-only transactions can execute at all sites atomically. The proposed algorithm can have transactions execute concurrently at the site to which they are submitted and, after the completion of each transaction, the update protocol is performed for updating their data items and checking their serializability. Therefore, the degree of parallelism of the transactions can be improved. Especially, if the probability of conflict among transactions is low, we can expect the higher degree of their parallelism.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.148-155
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• 2007

The routing optimization mode, which Mobile IPv6 provides for the direct communication between a mobile node and its correspond node, introduces various security threats, thus causing several protocols to be proposed for the secure binding update procedure. In particular, the Kang-Park protocol, which Kang and Park presented in 2005, achieves the optimized cryptographic operations and the strong security, while based on its unique security proxy structure. In spite of such advantages, it has some drawbacks in terms of security and efficiency. This paper improves the Kang-Park protocol through the strong CoA validation and early binding update methods. Also, we show that the improved protocol is better than others.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.267-274
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• 2006

The process of binding update for the routing optimization in MIPv6 can make the involved MN (Mobile Node) and CN(Correspondent Node) vulnerable to various attacks. Therefore, securing binding update process becomes an important research issue in the MIPv6, and several secure binding update protocols have been proposed. In this paper, we compare several existing binding update protocols, and analyze the vulnerability of MNs and CNs to the possible attacks and the management overhead of the SUCV(Statistic Uniqueness and Cryptographic Verifiability) which is considered to be superior to other protocols. Then, we propose an advanced protocol to resolve above drawbacks. Through the detailed analysis, we show that our protocol can reduce the computational overhead of MN, enable better management, and achieve a higher level of security against the redirect attacks, DoS(Denial of Service) attacks and brute force attacks, compared to SUCV.

• The Journal of Korean Association of Computer Education
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• v.10 no.5
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• pp.81-88
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• 2007

To support the movement of a mobile network consisting of several mobile nodes, the IETF NEMO working group proposed NEMO basic support protocol using bi-directional tunneling between the home agent and the mobile router. Since NEMO basic support protocol is based on bi-directional tunneling, all communications to and from mobile nodes are suffer from inefficient routing all the cases. To solve the routing inefficiency problem, several proposals are proposed. However, those proposals results in new problems, such as binding update storm and changes in existing protocol. Especially, binding update storm problem may cause the delay in binding update, this subsequently causes the difficulty for a real time service and the handoff delay on the movement of mobile network. In this paper, we propose a new binding update scheme which reduces binding update latency and the handoff delay through the distribution of the transmission time of binding update messages. The performance of the proposed scheme is also evaluated to demonstrate its efficiency. Simulation results show that the proposed scheme can efficiently reduce the binding update latency.