In this paper, we study the fundamental limits of a wireless sensor network’s lifetime under connectivity and k-coverage constraints. We consider a wireless sensor network with n sensors deployed independently and uniformly in a square field of unit area. Each sensor is active with probability p, independently from others, and each active sensor can sense a disc area with radius rs. Moreover, c...

Consider a set of mobile clients represented by n points in the plane moving at constant speed along n different straight lines. We study the problem of covering all mobile clients using a set of k disks centered at k fixed centers. Each disk exists only at one instant and while it does, covers any client within its coverage radius. The task is to select an activation time and a radius for each...

In Niger, independent mobile health units intended to meet the needs of nomadic populations have proved ineffectual and excessively costly. Primary health care services should be based on fixed structures with a reasonably wide radius of coverage and sufficient flexibility and mobile capacity to fulfil their obligations to all sectors of the population.

The addition of dopants with a small ionic radius led to strong binding H atoms, and the balance H+ reactivity (mobility) coverage was fundamentally important for high conductivity catalysis involving surface protonics.

We present an interactive visualization system for exploring the coverage in sensor networks with uncertain sensor locations. We consider a simple case of uncertainty where the location of each sensor is confined to a discrete number of points sampled uniformly at random from a region with a fixed radius. Employing techniques from topological data analysis, we model and visualize network covera...

When designing an aperture-synthesis telescope for use in astronomy it is essential to find a layout of the antennas on the site that provides good coverage of the uv-plane. Large holes in the distribution of baseline points in that plane are particularly undesirable, and so an algorithm was devised for locating all the holes in any given design and assessing whether they are unacceptably large...

The present third generation (3G) wireless technology can provide data oriented applications. However, the bit rate is limited to around 2 Mbps with limited mobility. Today, more applications demand high data rate and reasonable mobility. Therefore, by integrating 3G cellular system and wireless local area network (WLAN), there is a potential to push the data rate higher. This integration means...

The broadcasting of TV programs to the mobile phone can be enabled by the newly developed technology called DVB-H (Digital Video Broadcasting for Handheld). Because of the scarcity and cost of frequency resources, frequency reuse needs to be considered when rolling out DVB-H networks. By simulcasting the same content from several transmitters, a single frequency network (SFN) can provide a good...

Suppose that X has a k -variate spherically symmetric distribution with mean vector θ and identity covariance matrix. We present two spherical confidence sets for θ, both centred at a positive part Stein estimator T C S .X/. In the first, we obtain the radius by approximating the upper α-point of the sampling distribution of kT C S .X/ θk2 by the first two non-zero terms of its Taylor series ab...

We consider the indirect covering subtree problem (Kim et al., 1996). The input is an edge weighted tree graph along with customers located at the nodes. Each customer is associated with a radius and a penalty. The goal is to locate a tree-shaped facility such that the sum of setup and penalty cost is minimized. The setup cost equals the sum of edge lengths taken by the facility and the penalty...