An algorithm for routing messages between processing elements in a multiprocessor system which tolerates a maximal number of faulty links

An algorithm for routing messages between processing elements in a multiprocessor system is proposed. The algorithm can always be performed when the system is a connected graph. Comparisons are made with some known algorithms. The algorithm has been illustrated on an n-dimensional hypercube but can be applied on an arbitrary connected multiprocessor system.     

Computational complexity in additive hedonic games

We investigate the computational complexity of several decision problems in hedonic coalition formation games and demonstrate that attaining stability in such games remains NP-hard even when they are additive. Precisely, we prove that when either core stability or strict core stability is under consideration, the existence problem of a stable coalition structure is NP-hard in the strong sense. Furthermore, the corresponding decision problems with respect to the existence of a Nash stable coalition structure and of an individually stable coalition structure turn out to be NP-complete in the strong sense.     

Development of a heavy demining machine

Heavy demining machines are intended for humanitarian demining of larger mine-suspected areas. Two combinations of tools were considered herein: a working tool with two-flails, and a design with one flail and one tiller, and analyze the function of these variants. Some time ago, it was unimaginable to combine a flail and tiller, mostly because power demands were too high. Nonetheless, by suitably allocating the power to the working tools a realistic option was designed, which should be feasible even for smaller sized machines. In order to destroy AP and AT mines, the primary role is given to a flail of high diameter, and a backup function to the tiller whose diameter is two times lower. The depth and rpm of the tiller may be controlled independently of the flail, which ensures that digging depth is good enough. With two independent and different tools the density of hammer strikes is immediately adaptable to the conditions of mine density at different depths. The required force of the hammer impulse is determined in order to be able to overcome the resistance from digging the soil resistance. Furthermore, the independence of tool adaptation together with remote control improves the speed of mine clearing. A high reliability of mine destruction is thereby ensured. The results of machine testing show high graded performance regarding mine-clearance quality.     

Composites of multiwall carbon nanotubes and conducting polyaniline: Bulk samples and films produced from a solution in chloroform

Multiwall carbon nanotubes and conducting polyaniline, doped with dodecylbenzenesulfonic acid, are blended by employing the solubility of both materials in chloroform. Pellets are made by pressing the dried powder of the obtained composite, and films by sedimentary deposition onto a plastic substrate. In these composites, the advantageous properties of carbon nanotubes can be utilized in fully conducting bulk and planar structures while the strong decrease of the conductivity of doped polyaniline at low temperatures is simultaneously suppressed. The nanotube content in pellets can be as high as 40% by weight, and this wide range leads to a control over the shape and magnitude of the conductivity versus temperature curves. As the nanotube content grows, the temperature dependence of the conductivity becomes less steep, which is similar to the effect of annealing temperature on the conductivity of certain polycrystalline graphene films. In our case, this change is most likely caused by the increase of the density of highly conducting channels and not by homogeneous delocalization effects.