• Journal of Information Processing Systems
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• 제8권1호
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• pp.175-190
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• 2012

Shuffling is an effective method to build a publicly verifiable mix network to implement verifiable anonymous channels that can be used for important cryptographic applications like electronic voting and electronic cash. One shuffling scheme by Groth is claimed to be secure and efficient. However, its soundness has not been formally proven. An attack against the soundness of this shuffling scheme is presented in this paper. Such an attack compromises the soundness of the mix network based on it. Two new shuffling protocols are designed on the basis of Groth's shuffling and batch verification techniques. The first new protocol is not completely sound, but is formally analyzed in regards to soundness, so it can be applied to build a mix network with formally proven soundness. The second new protocol is completely sound, so is more convenient to apply. Formal analysis in this paper guarantees that both new shuffling protocols can be employed to build mix networks with formally provable soundness. Both protocols prevent the attack against soundness in Groth's scheme. Both new shuffling protocols are very efficient as batch-verification-based efficiency-improving mechanisms have been adopted. The second protocol is even simpler and more elegant than the first one as it is based on a novel batch cryptographic technique.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.153-156
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• 2003

Conventional simulations for mobile ad hoc network so far are based on the "random walk" of the mobile nodes, which are not constrained by their surrounding spatial environments. In this paper, we present a geography-based mobility model, which reflects more realistic movements of the real world. This mobility model is used for performance evaluation of MANET routing protocols.protocols.

• Information and Communications Magazine
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• 제28권12호
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• pp.69-82
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• 2011

In recent years, the employment of directional antennas in ad hoc networks has significantly increased. MAC protocols for ad hoc networks with directional antennas have the potentiality of spatial reuse, large coverage range and network capacity, which mitigates the negative effects associated with omnidirectional antenna systems. However, they suffer from some issues such as hidden terminal problems, deafness, neighbor discovery, flaws with directional carrier sensing, etc. In this paper, we have surveyed the MAC protocols for ad hoc networks with directional antennas, which have been published in the literature, and compared them qualitatively in terms of major characteristics and network performances.

• Journal of the Korea Society for Simulation
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• 제14권4호
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• pp.95-106
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• 2005

Recent advances in wireless sensor networks have led to many routing protocols designed for energy-efficiency in wireless sensor networks. Despite that many routing protocols have been proposed in wireless sensor networks, a single routing protocol cannot be energy-efficient if the environment of the sensor network varies. This paper presents a fuzzy logic based Adaptive Routing (FAR) algorithm that provides energy-efficiency by dynamically changing protocols installed at the sensor nodes. The algorithm changes protocols based on the output of the fuzzy logic which is the fitness level of the protocols for the environment. A simulation is performed to show the usefulness of the proposed algorithm.

• Journal of the Korea Society for Simulation
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• 제29권3호
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• pp.73-82
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• 2020

In the fourth industrial revolution, wireless sensor networks (WSNs) are an important element of collecting and analyzing data in a variety of environments without human intervention. This sensor network is greatly affected by topology and routing protocols. Routing protocols, which affect energy consumption, are executed after deploying sensor nodes. Once built, they are difficult to change. Before the WSN is deployed, a routing protocol is carefully selected in view of various environments and the performance of the protocol is evaluated. In this paper, we propose a model to simulate multiple routing protocols using a discrete event system specification (DEVS). The DEVS-based proposed model simulates various situations without changes and structures of the its model as algorithms of the routing protocols are implemented in its coordinators model. To verify normal behaviors of the proposed model, the number of report delivery and the energy consumption of the sensor network were compared using representative protocols LEACH and Dijkstra. As a result, it was confirmed that the proposed model executes normally in both routing protocols.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제11권6호
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• pp.2234-2239
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• 2010

In this paper, the performance of ad-hoc wireless network protocols is analyzed under the vehicular communication environments. We estimate the throughput and delay of the protocols with packet sizes and various data traffics in expressways and metropolis by using QualNet simulator. It turns out that the performance of DSR protocol is better in expressways and the performance of AODV works well in metropolitan areas. Therefore, it is necessary that the proper protocols should be selected to provide the better performance according to the vehicular communication environments.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제8권6호
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• pp.520-527
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• 2015

The key exchange protocols are very crucial tools to provide the secure communication in the broadband satellite access network. They should be required to satisfy various requirements such as security, key confirmation, and key freshness. In this paper, we present the security functions in ETSI(European Telecommunications Standards Institute), and analyze the specification of the security primitives and the key exchange protocols for the authenticated key agreement between RCST(Return Channel Satellite Terminal) and NCC(Network Control Centre). ETSI key exchange protocols consists of Main Key Exchange, Quick Key Exchange, and Explicit Key Exchange. We analyse the pros and cons of key exchange protocols based on performance analysis and performance evaluation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.1909-1928
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• 2011

Node cooperation during packet forwarding operations is critically important for fair resource utilization in Community Wireless Mesh Networks (CoWMNs). In a CoWMN, node cooperation is achieved by using fairness protocols specifically designed to detect and isolate malicious nodes, discourage unfair behavior, and encourage node participation in forwarding packets. In general, these protocols can be split into two groups: Incentive-based ones, which are managed centrally, and use credit allocation schemes. In contrast, reputation-based protocols that are decentralized, and rely on information exchange among neighboring nodes. Centrally managed protocols inevitably suffer from scalability problems. The decentralized, reputation-based protocols lacks in detection capability, suffer from false detections and error propagation compared to the centralized, incentive-based protocols. In this study, we present a new fairness protocol management scheme, called Hybrid FPMS that captures the superior detection capability of incentive-based fairness protocols without the scalability problems inherently expected from a centralized management scheme as a network's size and density grows. Simulation results show that Hybrid FPMS is more efficient than the current centralized approach and significantly reduces the network delays and overhead.

• Nuclear Engineering and Technology
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• 제31권2호
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• pp.226-235
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• 1999

Applying digital network technology for advanced nuclear plant requires deterministic communication for tight safety requirements, timely and reliable data delivery for operation-critical and mission-critical characteristics of nuclear plant. Communication protocols, such as IEEE 802/4 Token Bus, IEEE 802/5 Token Ring, FDDI, and ARCnet, which have deterministic communication capability are partially applied to several nuclear power plants. Although digital communication technologies have many advantages, it is necessary to consider the noise immunity from electromagnetic interference (EMI), electrical interference, impulse noise, and heat noise before selecting specific digital network technology for nuclear plant. In this paper, we consider the token frame loss and data frame loss rate due to the link error event, frame size, and link data rate in different protocols, and evaluate the possibility of failure to meet the hard real-time requirement in nuclear plant.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제7권2호
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• pp.213-218
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• 2006

In this paper, we evaluate and compare performance between position-based and non-position-based routing protocols in a vehicular ad-hoc network. The protocols evaluated in this paper for many performance evaluation aspects are a position-based routing protocol, GPSR (Greedy Perimeter Stateless Routing), and the non-position-based such as AODV (Ad-hoc On-Demand Distance Vector) and DSR (Dynamic Source Routing) protocols. The three protocol characteristics such as Packet Delivery Ratio, Latency of first packet per connection, and Average number of hops depending on distance are compared and evaluated. As the result of simulation, the AODV performed better than the DSR. However, due to the high mobility characteristic of a vehicular ad-hoc network, GPSR, the position-based routing performs better than the non-position-based routing protocols such as AODV and DSR in a vehicular ad-hoc network environment.