A Computer-Vision Based Precision Seed Drill Guidance Assistance

in Computers and Electronics In Agriculture (2007), 59(1-2),

This paper presents a control mechanism aiming to position seed drills relative to the previous lines, while sowing. The position was measured by a machine vision system and used in a feedback control ... [more ▼]

This paper presents a control mechanism aiming to position seed drills relative to the previous lines, while sowing. The position was measured by a machine vision system and used in a feedback control loop. An articulated mechanism was used to ensure the lateral displacement of the drill relative to the tractor. The behaviour of the whole outfit was studied during several field tests. The standard deviation of the error, measured as the difference between the observed inter-row distance and its set value, was 23 mm and its range was less than 100 mm, which was sufficient to fulfil the requirements of the application. Sources of systematic errors were also identified as linked to the geometric considerations. Their correction requires an accurate mounting of the camera, which may be possible for a serial montage. [less ▲]

Computerization and routine use of dynamic risk index for acute myocardial infarction patients

Conference (1985, August)

A computerized method adapted for pulmonary function testing in unsedated horses

in Deegen, E.; Beadle, R. E. (Eds.) Lung Function and Respiratory Diseases in the Horse (1985)

Computerized tailored testing: Structured and calibred item banks for summative and formative evaluation

in European Journal of Education (1980), 15(3), 251-260

Computerized video multitracking of several small translucent fishes (glass eels) at night with fluorescent elastomer tags

Poster (2010, July)

European eels (Anguilla Anguilla), an endangered species with high economic value, exhibit very unusual features in their multistage catadromous life cycle at different life stages. The reproduction of ... [more ▼]

European eels (Anguilla Anguilla), an endangered species with high economic value, exhibit very unusual features in their multistage catadromous life cycle at different life stages. The reproduction of eel takes place in the Sargasso Sea. Leptocephalus larvae use ocean currents (mainly the Gulf Stream) to migrate to European coastal areas, and then metamorphose into glass eels probably as they reach the continental shelf. Glass eel then, enter estuaries to join the fresh waters network. Knowledge about glass eel biology and migration has mainly increased in the eighties, and it is now well established that the activity during the estuary migration depends mainly on tidal cycle, even if lunar and circadian rhythms and/or direct influence of light and tidal coefficient may interact. Different migratory tactics are suspected on the basis of recent laboratory experiments (Bolliet & Labonne, 2008; Bureau du Colombier et al., 2009), notably the existence of individuals swimming only with the current, others swimming with and against the current, and others presenting a weak degree of activity. The propensity to migrate and glass eels energy content would be linked and may result in different migratory behaviours possibly leading to estuarine settlement (Bureau du Colombier et al., 2007; 2009). Unfortunately, few are known about the glass eel swimming behaviours in estuaries, a crucial point to better understand their estuarine migration: such knowledge would help to characterize the migratory tactics and to better understand the link with energy status. The videotracking system [EthoVision Color-Pro 3.1 (Noldus Information Technology)] which allows to measure automatically the movements of individuals represents an interesting tool to progress in this questioning. Nowadays, video tracking to measure fish behaviours is relatively frequent, but is rather rare in the ecological studies. Moreover, tracking a transparent animal, under water current conditions is a real challenge, particularly at night. To detect the individuals, several eels are marked by a fluorescent VIE tag (Visible Implant Elastomer, Northwest Marine Technology Inc.). VIE do no affect growth, survival and behaviour of tagged glass eels. Initially developed to improve the identification of individual tags in mark-recapture studies of aquatic animals, VIE tags are used here for a new extreme application in ethometry: the study of behaviours of transparent animals in weaker luminosity and in the dark by automatic tracking technology. The individual identification is based on the fluorescent color (red, blue, yellow and green) emitted by the VIE tag injected in the muscle mass on the basis of dorsal fin. The detection of the four marks is excellent. It allows measuring the activity (notably path and speed) of each tagged individuals as a function of tidal and nycthemeral rhythms in the same chronotron (circular aquarium simulating the estuarine conditions) and spatial use at a wide time scale from second to week. Another advantage is the possibility of tracked animals to go out the analysed arena without error of identification when it appears again in the analysed zone. This multitracking method by fluorescent VIE tags could be applied to a large number of species (crustaceans, fish, holothurians, amphibians, …). References: Bolliet & Labonne, 2008 Journal of Experimental Marine Biology and Ecology 362, 125-130; Bureau du Colombier et al., 2007 Physiology & Behavior 92, 684-690 ; Bureau du Colombier et al., 2009 Journal of Fish Biology 74, 2002-2013. Acknowledgements: This work was financially supported by FNRS-FRS (National fund of Research, Belgium) (project n°2.4617.08, n°2.4569.06, n°2.4569.10F), by Hubert Curien Tournesol project and by an EGIDE Grant. We thank J-C. Aymes for its help in testing the video tracking software and system. We are also highly grateful to Jacques Rives for its help in settling and monitoring the experiments. [less ▲]

Computers in Veterinary Medicine - The situation in Belgium

in UEVP's Electronic Data Processing, München, 1983 (1983)

Computing accurately the induced land subsidence affecting the main sinking cities located at major river mouths

in Advances in Hydro-Science and Engineering - Volume 1 -ICHE Washington (1993)

Computing bounds for kernel-based policy evaluation in reinforcement learning

Report (2010)

This technical report proposes an approach for computing bounds on the finite-time return of a policy using kernel-based approximators from a sample of trajectories in a continuous state space and ... [more ▼]

This technical report proposes an approach for computing bounds on the finite-time return of a policy using kernel-based approximators from a sample of trajectories in a continuous state space and deterministic framework. [less ▲]

Computing Convex Hulls by Automata Iteration

in Lecture Notes in Computer Science (2008, July), 5148

This paper considers the problem of computing the real convex hull of a finite set of n-dimensional integer vectors. The starting point is a finite-automaton representation of the initial set of vectors ... [more ▼]

This paper considers the problem of computing the real convex hull of a finite set of n-dimensional integer vectors. The starting point is a finite-automaton representation of the initial set of vectors. The proposed method consists in computing a sequence of automata representing approximations of the convex hull and using extrapolation techniques to compute the limit of this sequence. The convex hull can then be directly computed from this limit in the form of an automatonbased representation of the corresponding set of real vectors. The technique is quite general and has been implemented. Also, our result fits in a wider scheme whose objective is to improve the techniques for converting automata-based representation of constraints to formulas. [less ▲]

COMT Val158Met polymorphism, verbalizing of emotion and activation of affective brain systems

in NeuroImage (2011), 55