The ship as symbol in the prehistory of Scandinavia and south-east Asia

The ship is the dominant element in the visual culture of the South Scandinavian Bronze Age, appearing in several different media, including rock carvings, decorated metalwork and above-ground monuments. Discussion has divided between those scholars who interpret this imagery in terms of long-distance exchange networks and those who emphasize its more local significance, including its deployment in mortuary ritual. A strikingly similar system is identified in Southeast Asia and part of Melanesia and can be interpreted through archaeological and ethnographic sources, but in this case there is no need to distinguish between 'practical' and 'symbolic' interpretations of the depictions of ships. This paper summarizes the evidence from this region and suggests that it can offer a fruitful source of comparison for archaeologists working in northern Europe.

Movements, activity patterns and home range of a female brown bear (Ursus arctos, L.) in the Rodopi Mountain Range, Greece

Movements and activity patterns of an adult radio-tagged female brown bear accompanied by her cubs were documented for the first time in Rodopi area (NE Greece) from August 2000 to July 2002. Average daily movements were 2.45 +/- 2.26 SD km, (range 0.15-8.5 km). The longest daily range could be related to human disturbance (hunting activity). The longest seasonal distance (211 km), during Summer 2001 coincided with the dissolution of the family. With cubs, the female was more active during daytime (73 % of all radio-readings) than when solitary (28 %). The female switched to a more crepuscular behaviour, after separation from the yearling (July 2001). According to pooled data from 924 activity - recording sessions, during the whole monitoring period, the female was almost twice as active during day time while rearing cubs (51 % active) than when solitary (23 %). The autumn and early winter home range size of the family was larger (280 km(2)) than after the separation from the cubs (59 km(2)). During the family group phase, home range size varied from 258 km(2) in autumn to 40 km(2) in winter (average denning period lasted 107 days : December 2000-March 2001). The bear hibernated in the Bulgarian part of the Rodopi Range during winters of 2001 and 2002.

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

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.

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.