We consider the problem of searching a polygonal room with two guards starting at a specified door point. While maintaining mutual visibility and without crossing the door, the guards must move along the boundary of the room and eventually meet again. We give polynomial time algorithms for finding a search schedule that minimizes the total distance travelled by the guards and for minimizing the...

This paper discusses the experimental evaluation of locationbased services, such as mobile guides, in the field. It identifies advantages and disadvantages of using such field experiments over and against other evaluation methods. We then describe a specific method of running field experiments that we have found to be useful. The use of various evaluation measures, tools and scales is then disc...

In this paper we present a solution for the routing problem related to university course timetabling. We propose a heuristic algorithm that reduces the total distance travelled by each group of student between the different buildings occupying classrooms. This heuristic was tested using real data from the faculty of economic and management sciences of Sfax in Tunisia. The obtained results have ...

Recently, data collection from seabed by means of underwater wireless sensor networks (UWSN) has attracted considerable attention. Autonomous underwater vehicles (AUVs) are increasingly used as UWSNs in underwater missions. Events and environmental parameters in underwater regions have a stochastic nature. The target area must be covered by sensors to observe and report events. A ‘topology cont...

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a primary pest of citrus due to its status as a vector of the citrus disease, huanglongbing. We evaluated the effects of light of specific wavelength and polarization on phototactic behavior of D. citri using a horizontal bioassay arena. Wavelength-associated positive phototaxis was associated with short wavelength UV...

There are many logistics nuances specific to bakery factories, making the design of their distribution network especially complex. In particular, products typically have a shelf life under week. To ensure that delivered end-customers with freshness, speed, quality, health, and safety prioritized, network, facility location, ordering system must be optimally designed. This study presents multi-s...

Consider the following classical search problem: given a target point p ∈ <, starting at the origin, find p with minimum cost, where cost is defined as the distance travelled. Let D = |p| be the distance of the point p from the origin. When no lower bound on D is given, no competitive search strategy exists. Demaine, Fekete and Gal (Online searching with turn cost, Theor. Comput. Sci., 361(2-3)...

BACKGROUND International travel is associated with an increased risk of enteric, vector-borne, sexually transmitted and blood-borne infections. These risks are even higher among immunocompromised people, such as those with HIV infection. We conducted a study to determine HIV-positive people's travel patterns and risk behaviours while abroad. METHODS We conducted an anonymous survey of HIV-pos...

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe-Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here,...