• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.22-33
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• 2009

Mobile Ad Hoc Networks (MANETs) are self-organized networks that do not rely in their operation on wired infrastructure. As in any networking technology, security is an essential element in MANET as well, for proliferation of this type of networks. But supporting secure communication in MANETs proved to be a significant challenge, mainly due to the fact that the set of nodes in the network can change frequently and rapidly and due to the lack of access to the wired infrastructure. In particular, the trust model and the authentication protocols, which were developed for wired and infrastructure-based networks, cannot be used in MANETs. In [1], we addressed the problem of efficient authentication of distributed mobile users in geographically large networks and proposed a new authentication scheme for this case of MANETs. The proposed scheme exploits randomized groups to efficiently share authentication information among nodes that together implement the function of a distributive Certification Authority(CA). In this paper, we analyze numerically the performance of authentication method using randomized groups and compare with the simulation result.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1829-1836
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• 2009

A wireless Ad-hoc network is willing to send and receive data and for other nodes, and it is a temporal network where the nodes with mobility are automatically constituted. This network has been studied to construct networks in the state where there is no infrastructure. The limited nodes and its frequent moving in a wireless Ad-hoc network have resulted in frequent network disconnection. Therefore, the data transmission rate should be secured in a wireless Ad-hoc network. This study proposes the method to improve QoS of data transmission considering the mobility of nodes that respond to path searching by means of AOMDV routing protocol. By applying the suggested method, it is possible to raise the transmission rate by improving the reliability of transmission path.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.343-348
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• 2014

A routing scheme called MCS-NLTC using a self-configuration marine network model and the diversity and heterogeneity of broadband wireless access technologies is newly proposed. The MCS-NLTC algorithm selects optimal nodes and carriers for every hop in optimal routes based on not conventional hop counts but normalized distances to destination ships (location information of destination ships). Normalized transmission characteristics of applications and carriers are considered to get optimal routes as well. The location information enhances convergence speed to get destinations, which makes the route search time faster. Evaluated performances are compared with those of the schemes based on max-win (OMH-MW), and normalized transmission characteristics (MCS-NTC).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.241-244
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• 2012

In mobile ad-hoc networks, it should be the most important issue to reduce the power consumption of communications, because the resource of a node is limited in these networks. In existing cluster-based routing protocols, cluster headers participate in almost all communication processes. Therefore the lifetime of the cluster header is shortened and it does not have the effective route. In the proposed cluster-based routing protocol, the cluster header transmits a control packet which gives the route information to member nodes. This makes that the cluster header decreases the number of participating in communications, and that node members do not have to communicate trough the cluster header. This results in extending the lifetime of the cluster header, and having the effective route, data transmission rate and improved stability of routes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.9
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• pp.3639-3662
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• 2020

The network capability to accomplish its functions in a timely fashion under failures and attacks is known as survivability. Ad hoc routing protocols have been studied and extended to various domains, such as Intelligent Transport Systems (ITSs), Unmanned Aerial Vehicles (UAVs), underwater acoustic networks, and Internet of Things (IoT) focusing on different aspects, such as security, QoS, energy. The existing solutions proposed in this domain incur substantial overhead and eventually become burden on the network, especially when there are fewer attacks or no attack at all. There is a need that the effectiveness of these routing protocols be analyzed in the presence of Denial of Service (DoS) attacks without any intrusion detection or prevention system. This will enable us to establish and identify the inherently stable routing protocols that are capable to survive longer in the presence of these attacks. This work presents a DoS attack case study to perform theoretical analysis of survivability on node and network level in the presence of DoS attacks. We evaluate the performance of reactive and proactive routing protocols and analyse their survivability. For experimentation, we use NS-2 simulator without detection or prevention capabilities. Results show that proactive protocols perform better in terms of throughput, overhead and packet drop.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.49-56
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• 2011

One of the most important VANET applications is providing active safety by broadcasting emergency messages. In order to prevent broadcast storm of flooding-based broadcasting scheme in which any node receiving message will rebroadcast, the existing protocols use the different methods to limit the number of relay nodes. Nevertheless, the existing protocols have low delivery ratio with high traffic density and cause message overhead. Currently, the dramatic increase in the number of vehicles equipped with Global Positioning System (GPS) and onboard radar created new application scenarios that were not feasible before. Consequently, we proposed a broadcasting protocol that selects relay node by using GPS-based position information and detecting neighboring vehicles with the help of onboard radar to. Simulation results show that our proposed protocol has better performance than the existing schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1092-1099
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• 2017

In this paper, we propose a novel geographical on-demand routing protocol for a mobile ad-hoc network (MANET) that resolves the broadcast storm problem of ad-hoc on-demand distance vector (AODV) routing protocol. The candidates relaying route request (RREQ) packet are geographically restricted by the locations of the destination and a (RREQ sender. Then, the duplicate RREQs, which are generally discarded in the protocols that follow the principle of the AODV, are parsed to avoid redundant RREQ rebroadcasts and to perform passive acknowledgement with respect to a RREQ rebroadcast. The proposed routing protocol is implemented by modifying the source code of the AODV in QualNet. It is shown through QualNet simulations that the proposed routing protocol significantly improves the packet delivery ratio and the latency of the AODV in high-density and heavy traffic network scenarios.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.11
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• pp.463-468
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• 2017

To sense a wide area with mobile nodes, the uniformity of node deployment is a very important issue. In this paper, we consider the coverage problem to sense big data in sparse mobile ad hoc networks. In most existing works on the coverage problem, it has been assumed that the number of nodes is large enough to cover the area in the network. However, the coverage problem in sparse mobile ad hoc networks differs in the sense that a long-distance between nodes should be formed to avoid the overlapping coverage areas. We formulate the sensor coverage problem in sparse mobile ad hoc networks and provide the solution to the problem by a self-organized approach without a central authority. The experimental results show that our approach is more efficient than the existing ones, subject to both of coverage areas and energy consumption.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.75-79
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• 2011

Wireless devices can communicate between each other without existing infrastructure in mobile Ad-hod network. Ad hoc networks can be used under difficult conditions, where it is difficult to construct infrastructures, such as shadowing areas, disaster areas, war area, and so on. In order to support to considerable and various wireless services, more spectrum resources are needed. However, efficient utilization of the frequency resource is difficult because of spectrum scarcity and the conventional frequency regulation. Ad-hoc networks employing cognitive radio (CR) system that guarantee high spectrum utilization provide effective way to increase the network capacity. In this paper, we simulate and compare the performance of conventional single and cooperative spectrum sensing with CR system using ad-hoc networks in additive white Gaussian noise (AWGN) and Rayleigh channel model. And we demonstrate performance improvement by analyzing the system performance.

• Journal of Fashion Business
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• v.22 no.4
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• pp.76-92
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• 2018

The purpose of this study is to find the meaning of women's fashion in the city culture of Paris in the nineteenth century by examining paintings by the Impressionists. The research method was based on literature survey and visual examination paintings, 224 paintings(by ${\acute{E}}douard$ Manet, James Tissot, Edgar DeGas, Gustave Cailleboat, Jean $B{\acute{e}}raud$, Pierre-Auguste Renoir) were analyzed in this study. The results are as follows: In the nineteenth century, Paris was a new city with new department stores. Department stores were centers of consumer culture, where the power of capital appeared rather than class. The spatial backgrounds of Impressionist paintings were places where they could see the consumption and leisure culture of urban people, such as outdoor parks, cafes, theaters, ballrooms, bars, streets, and the boats. As for the characteristics of women's fashion in paintings, it was found that various changes of artificial silhouettes were developed. Various frills, ruffles, gatherings, and pleats were thought to have been made by machines. In the urban space, many of the women's costumes stood out because of the black color. Not only the black color came to represent widows and mourning but the black outfits worn by women enhanced their sensual appearances. Women's fashion expressed in Impressionist paintings eventually contained a modern meaning that changed from 'class symbol' to 'expression of taste'. And the symbol of consumer and leisure culture showed, and a Demimonde's fashion became a trendsetter, and painters were used as an important element expressing modernity.