• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.436-438
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• 2003

Ad hoc Network에서 효율적인 데이터 트래픽의 전송을 위하여 AODV 라우팅 알고리즘을 보안한 DM-AODV(Disjoint Multipath AODV)와 이를 활용하여 Qos율 높인 트래픽 분산 알고리즘인 TPA(Traffic Partitioning Algorithm)을 제안한다. 첫째, dynamic한 Ad hoc network환경에서 사용될 수 있는 DM-AODV을 사용하여 중복 노드가 없는 multipath들과 그 경로 각각의 최소 대역폭(bandwidth)을 구하고 둘째, 소스 노드에 들어오는 트래픽의 요구 대역폭과 TPA을 사용하여, 네트워크가 정상 일 때 전달 될 main path들과 네트워크 장애 시 할당 될 alternative path들에 들어오는 트래픽을 dynamic하게 분산시킴으로써 어플리케이션이 요구하는 높은 대역폭의 트래픽 수용 가능성을 높이고, 들어오는 트래픽의 안정적인 대역폭 보장과 속도의 향상, 폭주(congestion)의 감소 효과를 나타낸다. 또한 Main path에 장애 발생시, 미리 계산된 alternative Path에 트래픽을 전송함으로서 들어오는 패킷의 손실을 최소한으로 한다. 본 논문에서는 Ad hoc network에서의 QoS를 높이는 두 알고리즘을 소개하고, 동작 원리를 알아본다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.159-166
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• 2018

The proliferation of information technologies made it possible to produce information products of different versions at much lower cost comparing to traditional physical products. Thus it is common for information product manufacturers to consider vertically differentiated product line for more profit through improved market coverage. Another salient characteristic of most information product is network externality. Existing researches dealing with vertical differentiation and network externality usually assumed oligopolistic market where vertically differentiated products are provided by competing companies, respectively. Moreover, they analyzed the essentially dynamic characteristic of network externality statically. In this study, different from the previous researches, the vertical differentiation strategy of a monopolistic company under network externality is dynamically analyzed. We used a two-period model to accommodate the dynamic feature of network externality. Based on the two-period model, the profit maximizing solutions are analyzed. The results showed that a monopolistic company has no incentive to differentiate products vertically when the network externality is absent. On the contrary, when the network externality exists, the monopolistic company can derive more profit by vertically differentiating the product line. It is also shown that, for more profit, the monopolistic company should keep the quality difference between the high quality product and the low quality product as greater as possible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1213-1237
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• 2019

Vehicular Ad-hoc Network (VANET) facilities envision future Intelligent Transporting Systems (ITSs) by providing inter-vehicle communication for metrics such as road surveillance, traffic information, and road condition. In recent years, vehicle manufacturers, researchers and academicians have devoted significant attention to vehicular communication technology because of its highly dynamic connectivity and self-organized, decentralized networking characteristics. However, due to VANET's high mobility, dynamic network topology and low communication coverage, dissemination of large data packets (e.g. multimedia content) is challenging. Clustering enhances network performance by maintaining communication link stability, sharing network resources and efficiently using bandwidth among nodes. This paper proposes a mobility-based, multi-hop clustering algorithm, (MBCA) for multimedia content broadcasting over an IEEE 802.11p-LTE-enabled hybrid VANET architecture. The OMNeT++ network simulator and a SUMO traffic generator are used to simulate a network scenario. The simulation results indicate that the proposed clustering algorithm over a hybrid VANET architecture improves the overall network stability and performance, resulting in an overall 20% increased cluster head duration, 20% increased cluster member duration, lower cluster overhead, 15% improved data packet delivery ratio and lower network delay from the referenced schemes [46], [47] and [50] during multimedia content dissemination over VANET.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.11
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• pp.3163-3181
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• 2023

Eavesdropping attacks have seriously threatened network security. Attackers could eavesdrop on target nodes and link to steal confidential data. In the traditional network architecture, the static routing path and the important nodes determined by the nature of network topology provide a great convenience for eavesdropping attacks. To resist monitoring attacks, this paper proposes a random routing mutation defense method based on dynamic path weight (DPW-RRM). It utilizes network centrality indicators to determine important nodes in the network topology and reduces the probability of important nodes in path selection, thereby distributing traffic to multiple communication paths, achieving the purpose of increasing the difficulty and cost of eavesdropping attacks. In addition, it dynamically adjusts the weight of the routing path through network state constraints to avoid link congestion and improve the availability of routing mutation. Experimental data shows that DPW-RRM could not only guarantee the normal algorithmic overhead, communication delay, and CPU load of the network, but also effectively resist eavesdropping attacks.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.364-371
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• 2009

We analyzed romance of the three kingdoms written by Luo Guanzhong by using complex network to compare its properties with those of social network. The three kingdom network has a scale free and hierarchical network properties. Human-human interaction networks are dramatically changing in response to time and space. Due to lack of the dynamic interacting data, the researches only focus to analysis for properties of the statical networks. The romance of the three kingdoms is a Chinese historical novel based upon events from the end of the Han Dynasty, the Three Kingdoms era of China, and the reunification of the land. There are over a thousand characters, over a three thousand human-human interactions, and the dynamic changed in human-human interactions in the historical novel. Here, we introduce that a possible method for analyzing about dynamic changing of the complex network.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.76-85
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• 1999

The intuitive understanding of the dynamic pattern generation in asymmetric networks may be useful for developing models of dynamic information processing. In this paper, dynamic behavior of the cyclic connection neural network, in which each neuron is connected only to its nearest neurons with binary synaptic weights of $\pm$ 1, has been investigated. Simulation results show that dynamic behavior of the network can be classified into only three categories: fixed points, limit cycles with basin and limit cycles with no basin. Furthermore, the number and the type of limit cycles generated by the networks have been derived through analytical method. The sufficient conditions for a state vector of $n$-neuron network to produce a limit cycle of $n$- or 2$n$-period are also given. The results show that the estimated number of limit cycles is an exponential function of $n$. On the basis of this study, cyclic connection neural network may be capable of storing a large number of dynamic information.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.41-49
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• 2007

Ethernet passive optical network(EPON) is the next-generation technology for supporting services of high-quality at low-cost. In the EPON, all optical network units(ONUs) have to share a limited uplink channel for upstream data. In order to satisfy bandwidth demands of users on high-capacity local access networks(LANs), the optical line terminal(OLT) efficiently divides and allocates time slots of uplink channel to all ONUs. We discuss previous schemes for dynamic bandwidth allocation(DBA), such as interleaved polling with adaptive cycle time(IPACT) and sliding cycle time(SLICT). In this paper, dynamic right sizing of maximum-windows(DRSM), as a novel bandwidth allocation service, is proposed for more effective and efficient time slot allocation of the uplink channel. DRSM which is based on past information of bandwidth allocated by OLT calculates maximum available bandwidth and dynamically alters the maximum window size for the next ONU. This scheme does not only exert every effort to meet bandwidth demands of ONUs with the possible scope, it also seeks fairness of bandwidth allocation among ONUs.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.1
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• pp.68-76
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• 1999

The intuitive understanding of the dynamic pattern generation in asymmetric networks may be useful for developing models of dynamic information processing. In this paper, dynamic behavior of the ring connection neural network in which each neuron is only to its nearest neurons with binary synaptic weights of ±1, has been inconnected vestigated Simulation results show that dynamic behavior of the network can be classified into only three categories: fixed points, limit cycles with basin and limit cycles with no basin. Furthermore, the number and the type of limit cycles generated by the networks have been derived through analytical method. The sufficient conditions for a state vector of n-neuron network to produce a limit cycle of n- or 2n-period are also given The results show that the estimated number of limit cycle is an exponential function of n. On the basis of this study, cyclic connection neural network may be capable of storing a large number of dynamic information.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.529-535
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• 2015

Biological networks have been handled with the static concept. However, life phenomena in cells occur depending on the cellular state and the external environment, and only a few proteins and their interactions are selectively activated. Therefore, we should adopt the dynamic network concept that the structure of a biological network varies along the flow of time. This concept is effective to analyze the progressive transition of the disease. In this paper, we applied the proposed method to Alzheimer's disease to analyze the structural and functional characteristics of the disease network. Using gene expression data and protein-protein interaction data, we constructed the sub-networks in accordance with the progress of disease (normal, early, middle and late). Based on this, we analyzed structural properties of the network. Furthermore, we found module structures in the network to analyze the functional properties of the sub-networks using the gene ontology analysis (GO). As a result, it was shown that the functional characteristics of the dynamics network is well compatible with the stage of the disease which shows that it can be used to describe important biological events of the disease. Via the proposed approach, it is possible to observe the molecular network change involved in the disease progression which is not generally investigated, and to understand the pathogenesis and progression mechanism of the disease at a molecular level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2861-2880
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• 2018

Mobile Ad hoc Networks (MANETs) have become a viable platform owing to their potential of providing communication without any pre-existing infrastructure and central administrating authority. Mutual support and co-operation among nodes are prerequisites for performing functions in such networks. The scarcity of resources makes it economical for nodes to conserve their resources and misbehave by avoiding participation in the network. Therefore, a mechanism is required to detect and handle such misbehaving nodes and promote co-operation in the network. Existing techniques for handling misbehaving nodes focus only on their current behaviour without considering the antecedent behaviour of nodes. In real world, a node may dynamically change its behaviour in accordance to its requirements. Hence, an efficient mechanism is required for providing security against such misbehaviour. This paper proposes an Adaptive Security Model which contemplates the present as well as anterior behaviour of nodes for providing security against dynamic node behaviour. The adaptivity of the model is nested in its ability to requite well-behaving nodes and penalize misbehaving ones in conformity with their overall behaviour. Simulation results indicate the efficiency of proposed scheme in securing the network from the menace of dynamic behaviour of nodes.