We propose an extensive-form game as a model for pricing roaming charges in 802.11 wireless data networks. We specify utility functions for the three agents involved in the game: the wireless user and the visited and home operators. With realistic assumptions, we use the model to find optimal roaming prices for delay insensitive users.

Wireless local area networks (WLANs) are becoming increasingly popular in offices, homes, and public places. In public “hotspots” such as airports and hotels, these networks can be used to provide broadband wireless connectivity for people on the move. In Finland, hotspot networks are operated by TeliaSonera and DNA Finland. Because of interference issues, only one WLAN network can usually be b...

The day-to-day experiences of aging citizens differ significantly from young, technologically savvy engineers. Yet, well-meaning engineers continue to design technologies for aging citizens, informed by skewed stereotypes of aging without deep engagements from these users. This paper describes a co-design project based on the principles of Participatory Design that sought to provide aging peopl...

Quantitatively distinguishing grassland degradation due to climatic variations from that due to human activities is of great significance to effectively governing degraded grassland and realizing sustainable utilization. The objective of this study was to differentiate these two types of drivers in the Liao River Basin during 1999-2009 using the residual trend (RESTREND) method and to evaluate ...

Although global change is known to influence plant invasion, little is known about interactions between altered precipitation and invasion. In the North American mixedgrass prairie, invasive species are often abundant in wet and nitrogen (N)-rich areas, suggesting that predicted changes in precipitation and N deposition could exacerbate invasion. Here, this possibility was tested by seeding six...

In 2008, a Trichinella spp. outbreak occurred on a small family-owned pig farm in Mecklenburg-Western Pomerania in northeastern Germany. To obtain epidemiologic information on this outbreak, we determined that after 2005 the prevalence of Trichinella spp. in wild boars has increased in this region of Germany. We discuss the potential role of the raccoon dog in the increase in Trichinella spp. p...

Rabies transmitted by domestic dogs is a serious yet neglected public health threat in many underserved communities in Africa and Asia. Achieving 70% vaccination coverage in dog populations through annual mass vaccination campaigns is an effective means of controlling the disease in these communities. Evaluating the extent to which this target coverage is achieved requires either accurate pre-c...

Free-roaming cats may experience numerous hazardous encounters in the outdoor environment, including: vehicular accidents, aggression from other animals and exposure to infectious disease. This research quantitatively examined the outdoor activities of 55 owned cats by monitoring pets outfitted with 'KittyCam' video cameras. KittyCams are a type of Crittercam, designed by National Geographic to...

In a secure roaming scenario, a user U travels to a foreign network and communicates with a foreign server V securely so that no one other than U and V can obtain the messages exchanged between them. U may also want to travel anonymously so that no one including V can find out its identity or trace its whereabouts except its home server H . There have been many key establishment protocols propo...

Wireless LAN technologies have picked up momentum in the recent years due to their ease of deployment, cost and availability. The era of wireless LAN has also given rise to unique applications like VOIP, IPTV and unified messaging. However, these real-time applications are very sensitive to network and handoff latencies. To successfully support these applications, seamless roaming during the mo...