Simultaneous localization and map-building using active vision

An active approach to sensing can provide the focused measurement capability over a wide field of view which allows correctly formulated Simultaneous Localization and Map-Building (SLAM) to be implemented with vision, permitting repeatable long-term localization using only naturally occurring, automatically-detected features. In this paper, we present the first example of a general system for autonomous localization using active vision, enabled here by a high-performance stereo head, addressing such issues as uncertainty-based measurement selection, automatic map-maintenance, and goal-directed steering. We present varied real-time experiments in a complex environment.Published versio

Cold water aquifer storage

A working prototype system is described in which water is pumped from an aquifer at 70 F in the winter time, chilled to a temperature of less than 50 F, injected into a ground-water aquifer, stored for a period of several months, pumped back to the surface in the summer time. A total of 8.1 million gallons of chilled water at an average temperature of 48 F were injected. This was followed by a storage period of 100 days. The recovery cycle was completed a year later with a total of 8.1 million gallons recovered. Approximately 20 percent of the chill energy was recovered

Female teat size is a reliable indicator of annual breeding success in European badgers: Genetic validation

Assessing which females have bred successfully is a central requirement in many ecological field studies, providing an estimate of the effective female population size. Researchers have applied teat measurements previously to assess whether females, in a variety of mammalian species, have bred; however, this technique has not been validated genetically. Furthermore, several analytical techniques are available to classify individuals, but their misclassification rates have not been compared. We used 22 microsatellite loci to assign maternity, with 95% confidence, within a high-density population of European badgers Meles meles, as plural and subterranean breeding means that maternity cannot be inferred from behavioural observations. The teat lengths and diameters of 136 females, measured May–July 1994–2005, from social groups in which all offspring were assigned a mother, were reliable indicators of recent breeding success. A Generalised Linear Mixed Model (GLMM) classified both breeding and non-breeding females with lower error rates than discriminant analyses and crude teat-size criteria. The GLMM model logit probability = −20 + 1.8 month + 1.6 mean teat length + 1.0 mean teat diameter can be applied quickly in the field to assess the probability with which a female badger should be assigned maternity. This is a low-cost measure which, after validation, could be used in other badger or mammalian populations to assess the breeding success of females. This may be a particularly useful welfare tool for veterinary practitioners, especially during badger culls

Glassy behaviour in a simple topological model

In this article we study a simple, purely topological, cellular model which is allowed to evolve through a Glauber-Kawasaki process. We find a non-thermodynamic transition to a glassy phase in which the energy (defined as the square of the local cell topological charge) fails to reach the equilibrium value below a characteristic temperature which is dependent on the cooling rate. We investigate a correlation function which exhibits aging behaviour, and follows a master curve in the stationary regime when time is rescaled by a factor of the relaxation time t_r. This master curve can be fitted by a von Schweidler law in the late beta-relaxation regime. The relaxation times can be well-fitted at all temperatures by an offset Arrhenius law. A power law can be fitted to an intermediate temperature regime; the exponent of the power law and the von Schweidler law roughly agree with the relationship predicted by Mode-coupling Theory. By defining a suitable response function, we find that the fluctuation-dissipation ratio is held until sometime later than the appearance of the plateaux; non-monotonicity of the response is observed after this ratio is broken, a feature which has been observed in other models with dynamics involving activated processes.Comment: 11 pages LaTeX; minor textual corrcetions, minor corrections to figs 4 & 7

Decay of Correlations in a Topological Glass

In this paper we continue the study of a topological glassy system. The state space of the model is given by all triangulations of a sphere with $N$ nodes, half of which are red and half are blue. Red nodes want to have 5 neighbors while blue ones want 7. Energies of nodes with other numbers of neighbors are supposed to be positive. The dynamics is that of flipping the diagonal between two adjacent triangles, with a temperature dependent probability. We consider the system at very low temperatures. We concentrate on several new aspects of this model: Starting from a detailed description of the stationary state, we conclude that pairs of defects (nodes with the "wrong" degree) move with very high mobility along 1-dimensional paths. As they wander around, they encounter single defects, which they then move "sideways" with a geometrically defined probability. This induces a diffusive motion of the single defects. If they meet, they annihilate, lowering the energy of the system. We both estimate the decay of energy to equilibrium, as well as the correlations. In particular, we find a decay like $t^{-0.4}$

Partons and Jets at the LHC

I review some issues related to short distance QCD and its relation to the experimental program of the Large Hadron Collider (LHC) now under construction in Geneva.Comment: Talk at the conference QCD2002 at IIT Kanpur, India, November 2002. Ten pages with 12 figure

Photoemission spectra of many-polaron systems

The cross over from low to high carrier densities in a many-polaron system is studied in the framework of the one-dimensional spinless Holstein model, using unbiased numerical methods. Combining a novel quantum Monte Carlo approach and exact diagonalization, accurate results for the single-particle spectrum and the electronic kinetic energy on fairly large systems are obtained. A detailed investigation of the quality of the Monte Carlo data is presented. In the physically most important adiabatic intermediate electron-phonon coupling regime, for which no analytical results are available, we observe a dissociation of polarons with increasing band filling, leading to normal metallic behavior, while for parameters favoring small polarons, no such density-driven changes occur. The present work points towards the inadequacy of single-polaron theories for a number of polaronic materials such as the manganites.Comment: 15 pages, 13 figures; final version, accepted for publication in Phys. Rev.

Reproductive Failure in UK Harbour Porpoises Phocoena phocoena : Legacy of Pollutant Exposure?

This research was supported by a Marie Curie International Outgoing Fellowship within the Seventh European Community Framework Programme (Project Cetacean-stressors, PIOF-GA-2010-276145 to PDJ and SM). Additional funding was provided through the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS) (Grants SSFA/2008 and SSFA / ASCOBANS / 2010 / 5 to SM). Analysis of Scottish reproductive and teeth samples was funded by the EC-funded BIOCET project (BIOaccumulation of persistent organic pollutants in small CETaceans in European waters: transport pathways and impact on reproduction, grant EVK3-2000-00027 to GJP), and Marine Scotland (GJP). Samples examined in this research were collected under the collaborative Cetacean Strandings Investigation Programme (http://ukstrandings.org/), which is funded by the Department for Environment, Food and Rural Affairs (Defra) and the UK’s Devolved Administrations in Scotland and Wales (http://sciencesearch.defra.gov.uk/Defaul​t.aspx?Menu=Menu&Module=More&Location=No​ne&Completed=0&ProjectID=15331) (grants to PDJ, RD). UK Defra also funded the chemical analysis under a service-level agreement with the Centre for Environment, Fisheries and Aquaculture Science (grants to RJL, JB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Prevention is better than cure, but...: Preventive medication as a risk to ordinariness?

Preventive health remains at the forefront of public health concerns; recent initiatives, such as the NHS health check, may lead to recommendations for medication in response to the identification of 'at risk' individuals. Little is known about lay views of preventive medication. This paper uses the case of aspirin as a prophylactic against heart disease to explore views among people invited to screening for a trial investigating the efficacy of such an approach. Qualitative interviews (N=46) and focus groups (N=5, participants 31) revealed dilemmas about preventive medication in the form of clashes between norms: first, in general terms, assumptions about the benefit of prevention were complicated by dislike of medication; second, the individual duty to engage in prevention was complicated by the need not to be over involved with one's own health; third, the potential appeal of this alternative approach to health promotion was complicated by unease about the implications of encouraging irresponsible behaviour among others. Though respondents made different decisions about using the drug, they reported very similar ways of trying to resolve these conflicts, drawing upon concepts of necessity and legitimisation and the special ordinariness of the particular dru

Diffractive jet production in a simple model with applications to HERA

In diffractive jet production, two high energy hadrons A and B collide and produce high transverse momentum jets, while hadron A is diffractively scattered. Ingelman and Schlein predicted this phenomenon. In their model, part of the longitudinal momentum transferred from hadron A is delivered to the jet system, part is lost. Lossless diffractive jet production, in which all of this longitudinal momentum is delivered to the jet system, has been discussed by Collins, Frankfurt, and Strikman. We study the structure of lossless diffractive jet production in a simple model. The model suggests that the phenomenon can be probed experimentally at HERA, with A being a proton and B being a bremsstrahlung photon with virtuality $Q^2$. Lossless events should be present for small $Q^2$, but not for $Q^2$ larger than $1/R_{\rm P}^2$, where $R_{\rm P}$ is a characteristic size of the pomeron.Comment: 23 pages, REVTeX 3.0 with 8 postscript figures compressed with uufiles, OITS 536 and AZPH-TH/94-0