A bridge-ship collision avoidance system based on FLIR image sequences

In this paper, a forward-looking infrared (FLIR) video surveillance system is presented for collision avoidance of moving ships to bridge piers. An image preprocessing algorithm is proposed to reduce clutter background by multi-scale fractal analysis, in which the blanket method is used for fractal feature computation. Then, the moving ship detection algorithm is developed from image differentials of the fractal feature in the region of surveillance between regularly interval frames. When the moving ships are detected in region of surveillance, the device for safety alert is triggered. Experimental results have shown that the approach is feasible and effective. It has achieved real-time and reliable alert to avoid collisions of moving ships to bridge piers.

An FLIR video surveillance system to avoid bridge-ship collision

In this paper, a forward-looking infrared (FLIR) video surveillance system is presented for collision avoidance of moving ships to bridge piers. An image pre-processing algorithm is proposed to reduce clutter noises by multi-scale fractal analysis, in which the blanket method is used for fractal feature computation. Then, the moving ship detection algorithm is developed from image differentials of the fractal feature in the region of surveillance between regularly interval frames. Experimental results have shown that the approach is feasible and effective. It has achieved real-time and reliable alert to avoid collisions of moving ships to bridge piers

Autonomous ship collision free trajectory navigation and control algorithms

A new autonomous ship collision free (ASCF) trajectory navigation and control system has been introduced with a new recursive navigation algorithm based on analytic geometry and convex set theory for ship collision free guidance. The underlying assumption is that the geometric information of ship environment is available in the form of a polygon shaped free space, which may be easily generated from a 2D image or plots relating to physical hazards or other constraints such as collision avoidance regulations. The navigation command is given as a heading command sequence based on generating a way point which falls within a small neighborhood of the current position, and the sequence of the way points along the trajectory are guaranteed to lie within a bounded obstacle free region using convex set theory. A neurofuzzy network predictor which in practice uses only observed input/output data generated by on board sensors or external sensors (or a sensor fusion algorithm), based on using rudder deflection angle for the control of ship heading angle, is utilised in the simulation of an ESSO 190000 dwt tanker model to demonstrate the effectiveness of the system.

Survival, Pb-uptake and behaviour of three species of earthworm in Pb treated soils determined using an OECD-style toxicity test and a soil avoidance test

Mature (clitellate) Eisenia andrei Bouche (ultra epigeic), Lumbricus rubellus Hoffmeister (epigeic), and Aporrectodea caliginosa (Savigny) (endogeic) earthworms were placed in soils treated with Pb(NO3)(2) to have concentrations in the range 1000 to 10 000 mg Pb kg(-1). After 28 days LC50(-95%confidence limit) (+95%confidence limit) values were E. andrei 5824(-361)(+898) mg Pb kg(-1), L. rubellus 2867(-193)(+145) mg Pb kg(-1) and A. caliginosa 2747(-304)(+239) mg Pb kg(-1) and EC50s for weight change were E. andrei 2841(-68)(+150) Pb kg(-1), L. rubellus 1303(-201)(+204) mg Pb kg(-1) and A. caliginosa 1208(-206)(+212) Mg Pb kg(-1). At any given soil Pb concentration, Pb tissue concentrations after 28 days were the same for all three earthworm species. In a soil avoidance test there was no difference between the behaviour of the different species. The lower sensitivity to Pb exhibited by E. andrei is most likely due to physiological adaptations associated with the modes of life of the earthworms, and could have serious implications for the use of this earthworm as the species of choice in standard toxicological testing. (c) 2005 Elsevier Ltd. All rights reserved.

Computationally efficient expressions for the collision efficiency between electrically charged aerosol particles and cloud droplets

A multiple factor parametrization is described to permit the efficient calculation of collision efficiency (E) between electrically charged aerosol particles and neutral cloud droplets in numerical models of cloud and climate. The four-parameter representation summarizes the results obtained from a detailed microphysical model of E, which accounts for the different forces acting on the aerosol in the path of falling cloud droplets. The parametrization's range of validity is for aerosol particle radii of 0.4 to 10 mu m, aerosol particle densities of I to 2.0 g cm(-3), aerosol particle charges from neutral to 100 elementary charges and drop radii from 18.55 to 142 mu m. The parametrization yields values of E well within an order of magnitude of the detailed model's values, from a dataset of 3978 E values. Of these values 95% have modelled to parametrized ratios between 0.5 and 1.5 for aerosol particle sizes ranging between 0.4 and 2.0 mu m, and about 96% in the second size range. This parametrization speeds up the calculation of E by a factor of similar to 10(3) compared with the original microphysical model, permitting the inclusion of electric charge effects in numerical cloud and climate models.

The politics of CAP reform: Trade negotiations, institutional settings and blame avoidance

In this article we argue that the conclusion of the GATT Uruguay Round Agreement on Agriculture and the subsequent role of the WTO has changed the international context of CAP policy-making. However, comparing the three latest CAP reforms, we demonstrate that pressures on the CAP arising from international trade negotiations cannot alone account for the way in which the EU responds in terms of CAP reform. The institutional setting within which the reform package was determined also played a crucial role. Contrary to conventional wisdom, the CoAM seems to be a more conducive setting than the European Council for undertaking substantial reform of the CAP. We suggest that the choice of institutional setting is influenced by the desire of farm ministers and of heads of state or government to avoid blame for unpopular decisions. When CAP reform is an integral part of a broader package, farm ministers pass the final decision to the European Council and when CAP reform is defined as a separate issue the European Council avoids involvement.

Avoidance responses of an aphidophagous ladybird, Adalia bipunctata, to aphid-tending ants

1. Insect predators often aggregrate to patches of high prey density and use prey chemicals as cues for oviposition. If prey have mutualistic guardians such as ants, however, then these patches may be less suitable for predators. 2. Ants often tend aphids and defend them against predators such as ladybirds. Here, we show that ants can reduce ladybird performance by destroying eggs and physically attacking larvae and adults. 3. Unless ladybirds are able to defend against ant attacks they are likely to have adaptations to avoid ants. We show that Adalia bipunctata ladybirds not only move away from patches with Lasius niger ants, but also avoid laying eggs in these patches. Furthermore, ladybirds not only respond to ant presence, but also detect ant semiochemicals and alter oviposition strategy accordingly. 4. Ant semiochemicals may signal the extent of ant territories allowing aphid predators to effectively navigate a mosaic landscape of sub-optimal patches in search of less well-defended prey. Such avoidance probably benefits both ants and ladybirds, and the semiochemicals could be regarded as a means of cooperative communication between enemies. 5. Overall, ladybirds respond to a wide range of positive and negative oviposition cues that may trade-off with each other and internal motivation to determine the overall oviposition strategy.

Perceiving time to collision activates the sensorimotor cortex

The survival of many animals hinges upon their ability to avoid collisions with other animals or objects or to precisely control the timing of collisions. Optical expansion provides a compelling impression of object approach and in principle can provide the basis for judgments of time to collision (TTC) [1]. It has been demonstrated that pigeons [2] and houseflies [3] have neural systems that can initiate rapid coordinated actions on the basis of optical expansion. In the case of humans, the linkage between judgments of TTC and coordinated action has not been established at a cortical level. Using functional magnetic resonance imaging (fMRI), we identified superior-parietal and motor-cortex areas that are selectively active during perceptual TTC judgments, some of which are normally involved in producing reach-to-grasp responses. These activations could not be attributed to actual movement of participants. We demonstrate that networks involved in the computational problem of extracting TTC from expansion information have close correspondence with the sensorimotor systems that would be involved in preparing a timed motor response, such as catching a ball or avoiding collision.

Neural processing of imminent collision in humans

Detecting a looming object and its imminent collision is imperative to survival. For most humans, it is a fundamental aspect of daily activities such as driving, road crossing and participating in sport, yet little is known about how the brain both detects and responds to such stimuli. Here we use functional magnetic resonance imaging to assess neural response to looming stimuli in comparison with receding stimuli and motion-controlled static stimuli. We demonstrate for the first time that, in the human, the superior colliculus and the pulvinar nucleus of the thalamus respond to looming in addition to cortical regions associated with motor preparation. We also implicate the anterior insula in making timing computations for collision events.