Wireless Local Area Networks (WLANs) are now commonplace on many academic and corporate campuses. As "Wi-Fi" technology becomes ubiquitous, it is increasingly important to understand trends in the usage of these networks.This paper analyzes an extensive network trace from a mature 802.11 WLAN, including more than 550 access points 7000 users over seventeen weeks. We employ several measurement techniques, syslogs, telephone records, SNMP polling tcpdump packet sniffing. This largest WLAN...

Understanding user mobility is critical for simula- tions of mobile devices in a wireless network, but current models often do not reflect real movements. In this paper, we provide foundation such work by exploring characteristics traces users. We present method to estimate the physical location users from large trace associating with access points network. Using method, extracted tracks always-on Wi-Fi 13-month trace. discovered that speed and pause time each follow log-normal distribution...

All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. We provide a comprehensive review of six assumptions that are still part many ad hoc network studies, despite increasing awareness the need to represent more realistic features, including hills, obstacles, link asymmetries, unpredictable fading. use an extensive set measurements from large outdoor routing experiment demonstrate weakness these assumptions,...

Understanding usage patterns in wireless local-area networks (WLANs) is critical for those who develop, deploy, and manage WLAN technology, as well develop systems application software networks. This paper presents results from the largest most comprehensive trace of network activity a large, production LAN. For eleven weeks we traced nearly two thousand users drawn general campus population, using campus-wide 476 access points spread over 161 buildings. Our study expands on done by Tang...

Personal mobile devices are increasingly equipped with the capability to sense physical world (through cameras, microphones, and accelerometers, for example) the, network (with Wi-Fi Bluetooth interfaces). Such offer many new opportunities cooperative sensing applications. For example, users' phones may contribute data community-oriented information services, from city-wide pollution monitoring enterprise-wide detection of unauthorized access points. This people-centric mobile-sensing model...

Resistance exercise bands are a core component of any physical activity strengthening program. Strength training can mitigate the development sarcopenia, loss muscle mass or strength and function with aging. Yet, adherence such behavioral strategies in home-based setting fraught issues monitoring compliance. Our group developed Bluetooth-enabled resistance band capable transmitting data to an open-source platform. In this work, we application capture information real-time, conducted three...

Mobile health technology has great potential to increase healthcare quality, expand access services, reduce costs, and improve personal wellness public health. However, mHealth also raises significant privacy security challenges.

No abstract available.

MAC addresses can be easily spoofed in 802.11 wireless LANs. An adversary exploit this vulnerability to launch a large number of attacks. For example, an attacker may masquerade as legitimate access point disrupt network services or advertise false services, tricking nearby stations. On the other hand, received signal strength (RSS) is measurement that hard forge arbitrarily and it highly correlated transmitter's location. Assuming victim are separated by reasonable distance, RSS used...

Location is an important feature for many applications, and wireless networks can better serve their clients by anticipating client mobility. As a result, location predictors have been proposed in the literature, though few evaluated with empirical evidence. This paper reports on results of first extensive evaluation predictors, using two-year trace mobility patterns over 6,000 users Dartmouth's campus-wide Wi-Fi network. We implemented compared prediction accuracy several drawn from two...

Wireless network researchers are seriously starved for data about how real users, applications, and devices use networks under conditions. CRAWDAD (Community Resource Archiving Data at Dartmouth) is a new National Science Foundation-funded project to build wireless-network archive the research community. It will host wireless provide tools documents make collecting using easy. This resource should help identify evaluate interesting problems in mobile pervasive computing. To learn more...

Location is an important feature for many applications, and wireless networks may serve their clients better by anticipating client mobility. As a result, location predictors have been proposed in the literature, though few evaluated with empirical evidence. This paper reports on results of first extensive evaluation using two-year trace mobility patterns more than 6,000 users Dartmouth's campus-wide Wi-Fi network. The surprising provide critical evidence anyone designing or predictors. We...

Phenomenal improvements in the computational performance of multiprocessors have not been matched by comparable gains I/O system performance. This imbalance has resulted becoming a significant bottleneck for many scientific applications. One key to overcoming this is improving multiprocessor file systems. The design high-performance requires comprehensive understanding expected workload. Unfortunately, until recently, no general workload studies systems conducted. goal CHARISMA project was...

This study explores how privacy preferences vary with place and social context. These findings are useful for designing policies user interfaces pervasive computing.

We study the security challenges that arise in opportunistic people-centric sensing, a new sensing paradigm leveraging humans as part of infrastructure. Most prior sensor-network research has focused on collecting and processing environmental data using static topology an application-aware infrastructure, whereas involves collecting, storing, fusing large volumes related to everyday human activities. This highly dynamic mobile setting, where are central focus, presents for information...

Body-area networks of pervasive wearable devices are increasingly used for health monitoring, personal assistance, entertainment, and home automation. In an ideal world, a user would simply wear their desired set with no configuration necessary: the discover each other, recognize that they on same person, construct secure communications channel, to which attached. this paper we address portion vision by offering system unobtrusively recognizes person wearing it. Because it can user, our...

Common authentication methods based on passwords, tokens, or fingerprints perform one-time and rely users to log out from the computer terminal when they leave. Users often do not out, however, which is a security risk. The most common solution, inactivity timeouts, inevitably fail (too long timeout) usability short goals. One solution authenticate continuously while are using automatically them Several solutions user proximity, but these sufficient: only confirm whether nearby actually...

In this paper, we propose Auracle, a wearable earpiece that can automatically recognize eating behavior. More specifically, in free-living conditions, when and for how long person is eating. Using an off-the-shelf contact microphone placed behind the ear, Auracle captures sound of chewing as it passes through bone tissue head. This audio data then processed by custom analog/digital circuit board. To ensure reliable (yet comfortable) between skin, all hardware components are incorporated into...

Abstract Background The Assistant to Lift your Level of activitY (Ally) app is a smartphone application that combines financial incentives with chatbot-guided interventions encourage users reach personalized daily step goals. Purpose To evaluate the effects incentives, weekly planning, and self-monitoring prompts were used as intervention components part Ally app. Methods We conducted an 8 week optimization trial n = 274 insurees health insurance company in Switzerland. At baseline,...