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Full-Text Articles in Physical Sciences and Mathematics
An Assessment Of Threats Of The Physical And Mac Address Layers In Wimax/802.16, Krishnun Sansurooah
An Assessment Of Threats Of The Physical And Mac Address Layers In Wimax/802.16, Krishnun Sansurooah
Australian Information Security Management Conference
This paper investigates the risks and vulnerabilities associated to the security of the WiMAX/802.16 broadband wireless technology. One of the other aspects of this document will be to review all the associated weaknesses to the Medium Access Control (MAC) layer and at the physical (PHY) layer. The risks and impacts are assessed according to a systematic approach. The approach or methodology is used is according to the European Telecommunication Standards Institute (ETSI). These threats are enumerated and classified accordingly to their risk levels.
Evaluating Next Cell Predictors With Extensive Wi-Fi Mobility Data, Libo Song, David Kotz, Ravi Jain, Xiaoning He
Evaluating Next Cell Predictors With Extensive Wi-Fi Mobility Data, Libo Song, David Kotz, Ravi Jain, Xiaoning He
Dartmouth Scholarship
Location is an important feature for many applications, and wireless networks can better serve their clients by anticipating client mobility. As a result, many location predictors have been proposed in the literature, though few have been evaluated with empirical evidence. This paper reports on the results of the first extensive empirical evaluation of location predictors, using a two-year trace of the mobility patterns of over 6,000 users on Dartmouth's campus-wide Wi-Fi wireless network. The surprising results provide critical evidence for anyone designing or using mobility predictors. \par We implemented and compared the prediction accuracy of several location predictors drawn from …
Mobicom Poster Abstract: Bandwidth Reservation Using Wlan Handoff Prediction, Libo Song, Udayan Deshpande, Ulaş C. Kozat, David Kotz, Ravi Jain
Mobicom Poster Abstract: Bandwidth Reservation Using Wlan Handoff Prediction, Libo Song, Udayan Deshpande, Ulaş C. Kozat, David Kotz, Ravi Jain
Dartmouth Scholarship
Many network services may be improved or enabled by successful predictions of users' future mobility. The success of predictions depend on how much accuracy can be achieved on real data and on the sensitivity of particular applications to this achievable accuracy. We investigate these issues for the case of advanced bandwidth reservation using real WLAN traces collected on the Dartmouth College campus.
Risks Of Using Ap Locations Discovered Through War Driving, Minkyong Kim, Jeffrey J. Fielding, David Kotz
Risks Of Using Ap Locations Discovered Through War Driving, Minkyong Kim, Jeffrey J. Fielding, David Kotz
Dartmouth Scholarship
Many pervasive-computing applications depend on knowledge of user location. Because most current location-sensing techniques work only either indoors or outdoors, researchers have started using 802.11 beacon frames from access points (APs) to provide broader coverage. To use 802.11 beacons, they need to know AP locations. Because the actual locations are often unavailable, they use estimated locations from \em war driving. But these estimated locations may be different from actual locations. In this paper, we analyzed the errors in these estimates and the effect of these errors on other applications that depend on them. We found that the estimated AP locations …
Axiomatic Multi-Transport Bargaining: A Quantitative Method For Dynamic Transport Selection In Heterogeneous Multi-Transport Wireless Environments, Qiuyi Duan, Michael A. Goodrich, Charles D. Knutson, Lei Wang
Axiomatic Multi-Transport Bargaining: A Quantitative Method For Dynamic Transport Selection In Heterogeneous Multi-Transport Wireless Environments, Qiuyi Duan, Michael A. Goodrich, Charles D. Knutson, Lei Wang
Faculty Publications
Transport selection mechanisms are designed to facilitate seamless connectivity in heterogeneous multi-transport environments, allowing access to the “best” available transport according to user requirements. Evaluating transport configurations dynamically according to the user’s preferences and Quality of Service (QoS) requirements is a challenging task. This paper describes a quantitative approach that applies the Utility Theorem and Nash’s Bargaining solution to heterogeneous wireless environments. The mathematical model presented generates and adjusts the transport preference list dynamically depending on the degree to which a transport satisfies user preferences and the application’s QoS requirements. We incorporate a negotiation engine using the Axiomatic Multi-Transport Bargaining …
Channel Sampling Strategies For Monitoring Wireless Networks, Udayan Deshpande, Tristan Henderson, David Kotz
Channel Sampling Strategies For Monitoring Wireless Networks, Udayan Deshpande, Tristan Henderson, David Kotz
Dartmouth Scholarship
Monitoring the activity on an IEEE 802.11 network is useful for many applications, such as network management, optimizing deployment, or detecting network attacks. Deploying wireless sniffers to monitor every access point in an enterprise network, however, may be expensive or impractical. Moreover, some applications may require the deployment of multiple sniffers to monitor the numerous channels in an 802.11 network. In this paper, we explore sampling strategies for monitoring multiple channels in 802.11b/g networks. We describe a simple sampling strategy, where each channel is observed for an equal, predetermined length of time, and consider applications where such a strategy might …
Extracting A Mobility Model From Real User Traces, Minkyong Kim, David Kotz, Songkuk Kim
Extracting A Mobility Model From Real User Traces, Minkyong Kim, David Kotz, Songkuk Kim
Dartmouth Scholarship
Understanding user mobility is critical for simulations of mobile devices in a wireless network, but current mobility models often do not reflect real user movements. In this paper, we provide a foundation for such work by exploring mobility characteristics in traces of mobile users. We present a method to estimate the physical location of users from a large trace of mobile devices associating with access points in a wireless network. Using this method, we extracted tracks of always-on Wi-Fi devices from a 13-month trace. We discovered that the speed and pause time each follow a log-normal distribution and that the …
Predictability Of Wlan Mobility And Its Effects On Bandwidth Provisioning, Libo Song, Udayan Deshpande, Ulaş C. Kozat, David Kotz, Ravi Jain
Predictability Of Wlan Mobility And Its Effects On Bandwidth Provisioning, Libo Song, Udayan Deshpande, Ulaş C. Kozat, David Kotz, Ravi Jain
Dartmouth Scholarship
Wireless local area networks (WLANs) are emerging as a popular technology for access to the Internet and enterprise networks. In the long term, the success of WLANs depends on services that support mobile network clients. \par Although other researchers have explored mobility prediction in hypothetical scenarios, evaluating their predictors analytically or with synthetic data, few studies have been able to evaluate their predictors with real user mobility data. As a first step towards filling this fundamental gap, we work with a large data set collected from the Dartmouth College campus-wide wireless network that hosts more than 500 access points and …
Crawdad: A Community Resource For Archiving Wireless Data At Dartmouth, Jihwang Yeo, David Kotz, Tristan Henderson
Crawdad: A Community Resource For Archiving Wireless Data At Dartmouth, Jihwang Yeo, David Kotz, Tristan Henderson
Dartmouth Scholarship
Wireless network researchers are seriously starved for data about how real users, applications, and devices use real networks under real network conditions. CRAWDAD, a Community Resource for Archiving Wireless Data at Dartmouth, is a new NSF-funded project to build a wireless network data archive for the research community. We host wireless data, and provide tools and documents to make it easy to collect and use wireless network data. We hope that this resource will help researchers identify and evaluate real and interesting problems in mobile and pervasive computing. This report outlines the CRAWDAD project, the kick-off workshop that was held …
On Improving Wireless Broadcast Reliability Of Sensor Networks Using Erasure Codes, Rajnish Kumar, Arnab Paul, Umakishore Ramachandran, David Kotz
On Improving Wireless Broadcast Reliability Of Sensor Networks Using Erasure Codes, Rajnish Kumar, Arnab Paul, Umakishore Ramachandran, David Kotz
Dartmouth Scholarship
Efficient and reliable dissemination of information over a large area is a critical ability of a sensor network for various reasons such as software updates and transferring large data objects (e.g., surveillance images). Thus efficiency of wireless broadcast is an important aspect of sensor network deployment. In this paper, we study FBcast, a new broadcast protocol based on the principles of modern erasure codes. We show that our approach provides high reliability, often considered critical for disseminating codes. In addition FBcast offers limited data confidentiality. For a large network, where every node may not be reachable by the source, we …