• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.25-27
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• 2004

시스템이 대형화가 되어가고 네트워크 환경이 발전함에 따라 분산 환경이 점점 더 증대되어 가고 있다. 이러한 분산 환경에서 사용되는 리더 선출 알고리즘(Leader Election Algorithm)은 다양하게 제시되었고 본 논문에서는 Garcia-Molina가 제시한 Bully 알고리즘을 프로세스 알제브라 언어인 CSP로 명세하고 FDR 모델체킹 도구를 이용해 해당 요구사항을 만족하는지 검증하였다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2855-2861
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• 1998

Election is a fundamental problem in the distributed computing. We consider n nodes in the network with f maximum number of faulty links incident on each node, where $f{\le}{\llcorner}(n-1/2){\lrcorner}$. In general, electing a leader, finding the maximum identifier and constructing a spanning tree belong to the same class in the distributed computing because of the same order of the message complexity. Using a spanning tree, we prove that the lower bound of message complexity for a leader election algorithm in an asynchronous complete network with intermittent link faults is $O(n^3)$.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1542-1551
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• 2006

In the Grid Database, some replicas will have more requests from the clients than others. A fast consistency algorithm has been presented to satisfy the high demand nodes in a shorter period of time. But it has poor performance in multiple regions of high demand for forming the island of locally consistent replicas. Then, a leader election method is proposed, whereas it needs much additional cost for periodic leader election, information storage, and message passing, Also, false leader can be created. In this paper, we propose a tree-based algorithm for replica update propagation. Leader replicas with high demand are considered as the roots of trees which are interconnected. All the other replicas are sorted and considered as nodes of the trees. Once an update occurs at any replica, it need be transmitted to the leader replicas first. Every node that receives the update propagates it to its children in the tree. The update propagation is optimized by cost reduction for fixed propagation schedule. And it is also flexible for the dynamic model in which the demand conditions change with time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4543-4552
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• 2010

A leader is a special process who roles as the coordinator within multiple processes of a group. In a distributed system, leader election is the procedure of electing a coordinator. This is a very important issue for building fault-tolerant distributed systems. When two normal mobile ad hoc networks are merged, there are two leaders. This violates the safety property, so a mechanism to detect and handle are required. In mobile ad hoc distributed computing system, we propose a leader competition protocol and to prove the temporal logic to it. This solution is based on the group membership detection algorithm.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.829-834
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• 2004

Nodes communicate through wireless channels under peer-to-peer level in ad-hoc mobile networks. The nodes are free to move around in a geographical area and are loose]y bounded by the transmission range of the wireless channels. Also, a node is completely free to move around, there is no fixed final topology. Hence, to manage the inter-node communication and data exchange among them a leader node is required. In this paper we introduce an efficient leader election algorithm for mobile ad hoc networks where inter-node communication is allowed only among the neighboring nodes. Furthermore we present the result of performance evaluation through simulation. The algorithm is efficient and practical since it uses least amount of wireless resources and does not affect the movement of the nodes.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.53-62
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• 2008

The Election paradigm can be used as a building block in many practical problems such as group communication, atomic commit and replicated data management where a protocol coordinator might be useful. The problem has been widely studied in the research community since one reason for this wide interest is that many distributed protocols need an election protocol. However, despite its usefulness, to our knowledge there is no work that has been devoted to this problem in a mobile ad hoc computing environment. Mobile ad hoc systems are more prone to failures than conventional distributed systems. Solving election in such an environment requires from a set of mobile nodes to choose a unique node as a leader based on its priority despite failures or disconnections of mobile nodes. In this paper, we describe a solution to the election problem from mobile ad hoc computing systems. This solution is based on the Group Membership Detection algorithm.

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.453-461
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• 2010

Specifying and designing the election algorithm in mobile ad hoc distributed systems is very difficult task. It is because mobile ad hoc systems are more prone to failures than conventional distributed systems. The aim of this paper is to propose a specification and design of the election algorithm in a specific ad hoc mobile computing environment. For this aim, we specify and design an election algorithm in this paper. In addition, we formally verify it and show that it is correct. This solution is based on the nodes detection algorithm that is a classical one for synchronous distributed systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1027-1037
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• 1994

While the value of unidirectional delay was used as the preference of a node in the previous research on the performance of the leader, this paper proposes the value of bidirectional delay as a preference of a node and analyzies election strategies in the case of the various number of candidates through simulation. We made a comparative study to evaluate the quality of leaders chosen by the bidirectional preference and unidirectional preference in terms of relative error and from the standpoint of the probability of choosing the optimal leader.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.169-175
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• 2002

This paper is about the hardness of the Election problem in asynchronous distributed systems in which processes can crash but links are reliable. The hardness of the problem is defined with respect to the difficulty to solve it despite failures. It is shown that problems encountered in the system are classified as three classes of problems: F (fault-tolerant), NF (Not fault-tolerant) and NFC(NF-completeness). Among those, the class NFC is the hardest problems to solve. In this paper, we prove that the Election problem is the most difficult problem which belongs to the class NFC.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.166-183
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• 2013

It requires a lot of costs and manpower to manage an election. The electronic voting scheme can make the election system economic and trustful. The widespread use of smart phones causes mobile voting to be a major issue. The smart phone can be used as a mobile voting platform since it can carry out many services in addition to basic telephone service. To make mobile voting practical and trustful, we analyzed two subjects of study. Firstly, the way to make a biometric based mobile ID, which has legal binding forces. In mobile voting, user identification is accomplished on line since the voter should be able to vote wherever they go. The digital ID conducts a similar role to the need for a resident card. The user's identity is bound to the resident card legally. To bind the user's identity to the smart phone, we use USIM. Biometric recognition is also needed to authenticate the user, since the user cannot prove him or her on line face-to-face. The proposed mobile ID can be reissued by means of introducing a random secret value. Secondly, the mobile voting scheme is proposed where candidates can accept election results without doubt. The goal of an election is to select a leader among two or more candidates. Existing electronic voting schemes mainly focus on the study of ballot verification accomplished by voters. These approaches are not safe against collusion attacks where candidates and the election administration center are able to collude to fabricate election results. Therefore, a new type of voting and counting method is needed where candidates can directly take part in voting and counting stages. The biometric based multi-signature scheme is used to make the undeniable multi-signed ballot. The ballot cannot be verified without the help of all candidates. If candidates accept election results without a doubt, the fairness of the election is satisfied.