• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.350-356
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• 2008

The recent networks are trending toward wireless networks. So wireless internet used to service of wired networks. But wireless networks can't show same performance of wired networks. Therefore, we are must concerned about Routing Protocol for improvement of a weak point of physical feature. But many researchers are not focusing on developing Routing Protocol. In this paper, we improve on AODV(Ad-hoc On-demand Distance Vector) for Wireless Mesh Networks. And it analyzed the result of simulation.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.3
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• pp.92-101
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• 2010

Energy efficiency and safe mobility are the two key constituents of the future automobile. The technologies that enable these features are now heavily dependent upon information and communication technology rather than traditional auto-mechanical technology. This paper presents an exploratory project 'Smart&Green Vehicle Project' at Western Michigan University which is to improve the geographical location accuracy of vehicles and to study various applications of making such location data available. Global Positioning System (GPS), Inertial Navigation System (INS), Vehicular Ad-hoc Network (VANET) technology, and data fusion among these technologies are investigated. Testing and evaluation is done on systems which will gather vehicular positioning data during GPS signal loss. Vehicles in urban settings do not acquire accurate positioning data from GPS alone; therefore there is a need for exploration into technology that can assist GPS in urban settings. The goal of this project is to improve the accuracy of positioning data during a loss of GPS signal. Controlled experiments are performed to gather data which aided in assessing the feasibility of these technologies for use in vehicular platforms.

• Information and Communications Magazine
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• v.29 no.8
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• pp.72-84
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• 2012

This paper introduces three vehicle trajectory-based data forwarding schemes, tailored for vehicular ad hoc networks. Nowadays GPS-based navigation systems are popularly used for providing efficient driving paths for drivers. With the driving paths called vehicle trajectories, we can make data forwarding schemes more efficient, considering the micro-scoped mobility of individual vehicles in road networks as well as the macro-scoped mobility of vehicular traffic statistics. This paper shows why the vehicle trajectory is a key ingredient in the design of the vehicle-to-infrastructure, infrastructure-to-vehicle, and vehicle-to-vehicle data forwarding schemes over multihop. Through the mathematical formulation, the key design techniques are shown for three forwarding schemes based on vehicle trajectory, compared with a state-of- the- art data forwarding scheme based on only vehicular traffic statistics.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1015-1024
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• 2011

Mobile P2P protocols in ad-hoc networks have gained large attention recently. Although there has been much research on P2P algorithms for wired networks, existing P2P protocols are not suitable for mobile ad-hoc networks because they do not consider mobility of peers. This study proposes a new cluster-based P2P protocol for ad hoc networks which utilizes peer mobility. In typical cluster-based P2P algorithms, each cluster has a super peer and other peers of the cluster register their file list to the super peer. High mobility peers would cause a lot of file list registration traffic because they hand-off between clusters frequently. In the proposed scheme, while peers with low mobility behave in the same way as the peers of the typical cluster-based P2P schemes, peers with high mobility behave differently. They inform their entrance to the cluster region to the super peer but they do not register their file list to the super peer. When a peer wishes to find a file, it first searches the registered file list of the super peer and if fails, query message is broadcasted. We perform mathematical modeling, analysis and optimization of the proposed scheme regarding P2P traffic and associated routing traffic. Numerical results show that the proposed scheme performs much better than or similar to the typical cluster-based P2P scheme and flooding based Gnutella.

• Management Science and Financial Engineering
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• v.3 no.2
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• pp.1-27
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• 1997

Designing effective navigation aids for customer interfaces is critical for the success of cyber shopping malls. Navigation aids can be classified into either basic ones which are based on the structure of the malls or add-ons which are not. Add-on navigation aids provide various short-cuts to promote efficient traversal in the cyber shopping malls, but too many of them would increase the complexity of the customer interface. Metaphors have been used widely for the design of add-on navigation aids, but little research evaluates their impact on the processes and outcomes of customers behavior in cyber shopping malls. This paper presents an empirical study that investigates the navigation process of customers and the subjective evaluation of their shopping experience. This research implemented two versions of a test-bed cyber shopping mall according to different metaphors used; one based on a spatial metaphor, and the other based on a non spatial metaphor. The results of the experiment indicate that navigation aids based on the spatial metaphor were used more frequently, which resulted in better understanding about the entire structure of the cyber shopping malls, which in turn led to an increased ease of finding target items and also a more pleasant shopping experience. The benefits of navigation aids based on the spatial metaphor became more evident when customers were looking for ad-hoc category items rather than common items. This paper presents plausible explanations for the results and implications to the design of navigation aids for cyber shopping malls.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.158-167
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• 2002

In this paper, it is analyzed that WAP packet transmission time to improve performance of WAP using SAR-QT algorithm in Bluetooth channel. The order for SAR-QT algorithm to improve the transfer capability, it is fragmented in WTP total messages that are coming down from upper layer and then the packets are sent one at time in baseband. And it is studied that transmission time for WAP over Bluetooth according to DMI, DM3 or DM5 packet type using SAR-QT algorithm in Bluetooth piconet environment. This SAR-QT algorithm decreases WAP packet transmission time of L2CAP baseband packets by sending packet that are spanning multiple slots. From the results, in WAP over Bluetooth channels, it is found out that WTP packet size ought to be increased to decrease transmission time of WAP packet. In addition, considering BER in wireless channel, optimal WTP packet size is achieved for WAP over Bluetooth in a Rician fading environment.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.204-212
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• 2011

Mobile P2P(Peer-to-Peer) protocols in MANET(mobile ad-hoc networks) have gained much attention recently. Existing P2P protocols can be categorized into structured and unstructured ones. In MANET, structured P2P protocols show large control traffic because they does not consider the locality of P2P data and unstructured P2P protocols have a scalability problem with respect to the number of nodes. Hybrid P2P protocols combine advantages of the structured and unstructured P2P protocols. Cluster-based P2P protocol is one of the hybrid P2P protocols. Our study makes an analysis of the cluster-based P2P protocol and derives the optimal cluster formation in MANET. In the derived optimal cluster formation, the cluster-based P2P protocol shows better performance than Gnutella protocol with respect to control traffic.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.198-200
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• 2022

With the expansion of the global supply chain, the efficiency of maritime logistics is considered a crucial factor for countries' trade and competitiveness. Nevertheless, prior research has not thoroughly evaluated the efficiency of maritime logistics, including countries' ports and shipping capacities. Accordingly, this study examines integrated maritime logistics efficiency at the national level using DEA-CCR, BCC, and super-efficiency DEA. Furthermore, this study identifies a difference between the selected countries' maritime logistics efficiency and LPI (Logistics Performance Index) through Spearman's correlation test as an ad-hoc analysis. From this, Asian countries showed higher efficiency and European countries showed higher LPI scores. These results might be derived from this difference in port-city development patterns. Additionally, the main cause of inefficiency in Europe and Japan might be attributed to high fleet capacity of control. Consequently, this study can provide valuable implications for coastal countries to set more efficient directions for maritime logistics investment and policy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.590-598
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• 2016

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.211-215
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• 2015

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving. The intelligent vehicle network is comprised for the driving information offering changing rapidly of the communication(V2V: Vehicle to Vehicle) between the car and the car, communication(V2I : Vehicle to Infrastructure) between the infrastructure and the car, and V2X (Vehicle to Nomadic).