In the recent years a number of novel, automatic map-inference techniques have been proposed, which derive road-network from a cohort of GPS traces collected by a fleet of vehicles. In spite of considerable attention, these maps are imperfect in many ways: they create an abundance of spurious connections, have poor coverage, and are visually confusing. Hence, commercial and crowd-sourced mappin...

Imperfect coverage (IPC) occurs when a malicious component failure causes extensive damage due to inadequate fault detection, fault location or fault recovery. Common-cause failures (CCF) are multiple dependent component failures within a system due to a shared root cause. Both imperfect coverage and common-cause failures can exist in distributed computer systems and can contribute significantl...

Due to imperfect fault coverage, the reliability of redundant systems cannot be enhanced unlimitedly with the increase of redundancy. Thus it is essential to study the optimal structure of redundant systems. This paper considers a multi-state series-parallel system with two types of parallelization: redundancy and work sharing. Different from existing works which consider single-fault coverage,...

Several empirical studies have shown that sensing and communication ranges of sensors are not regular disks. Rather, they follow probabilistic models. Yet, many current coverage and connectivity protocols continue to assume the disk model for ease of analysis, which may lead to incorrect operation of these protocols in real environments. We propose a distributed coverage and connectivity mainte...

As polio eradication inches closer, the absence of poliovirus circulation in most of the world and imperfect vaccination coverage are resulting in immunity gaps and polio outbreaks affecting adults. Furthermore, imperfect, waning intestinal immunity among older children and adults permits reinfection and poliovirus shedding, prompting calls to extend the age range of vaccination campaigns even ...

Coordinated Multi-Point (CoMP) systems promise very high performance in terms of spectral efficiency and coverage benefits when perfect Channel State Information (CSI) is available at the transmitter. However, perfect CSI is difficult to obtain in CoMP systems due to an increased number of channel parameters to estimate at the receiver and to be fed back to the transmitter. So, the performance ...

In this paper outage performance of a secondary user (SU) is evaluated under an amplify and forward (AF) relay selection scheme with an imperfect channel state information (CSI) while the SU shares spectrum in an underlay cognitive radio network (CRN). In underlay, the SU coexists with primary user (PU) in the same band provided the interference produced by SU at the PU receiver is below an int...

An aim of some vaccination programmes is to reduce the prevalence of an infectious disease and ultimately to eradicate it. We show that eradication success depends on the type of vaccine as well as on the vaccination coverage. Vaccines that reduce the parasite within-host growth rate select for higher parasite virulence and this evolution may both increase the prevalence of the disease and prev...

This paper presents a two stage SIS epidemic model in animal population with bovine tuberculosis (BTB) in African buffalo as a guiding example. The proposed model is rigorously analyzed. The analysis reveals that the model exhibits the phenomenon of backward bifurcation, where a stable disease-free equilibrium (DFE) coexists with a stable endemic equilibrium (EE) when the associated reproductio...