Computer Modelling of a Tank Battle with Helicopter Support

The paper attempts to model a tank versus tank battle scenario in which the defender is provided an armed helicopter unit support, against surprise advance of the attacker towards an important place. The stochastic and dynamic nature of the battle system has been handled by means of Monte Carlo simulation. In that activities like move, search, fire, hit and kill are simulated and their effects generated in the model. The game has been repeated for parameters relating to (i) fire power (ii) mobility (iii) intervisibility (iv) blind shooting (v) defender/attacker force ratio and (vi) helicopter unit support with the defender. Then, average numerical effects in each case have been analysed.Although the results are based on tentative data, the. trend seems to suggest that a battalion of Centurion tanks or 2 coys with a helicopter unit support stand fairly good chance to defeat the attack by M-47/48 tanks equivalent to 4 coys. Neyertheless, the methodology provides an effective basis to systematically approach realistic situations and quantitatively assess weapon systems effectiveness under tactical alternatives and battle field environments

Generating Random Sampling Numbers

Simulation experiments with the help of random numbers are increasing in various Defence application areas. Some authors have brought out autocorrelations in the sequences generated by the computer methods. To overcome this defect, a new algorithm based on the concept of random sampling (with replacement) from a finite population has been developed. The constants in the linear congruential relation are chosen so that (a) the proportion of distinct numbers in the generation compares with the theoretical expectation and (b) the period of the generator covers almost the edtire population of 16-bit numbers. The criteria suggest to choose the variable multiplier (ai =2ai-1 +' 1) with initial value a. = 2^9+ 5 or 2^10 + 3. The randomness of the generation has been compared with that of a Bernoullian sequence

Computer Modelling of a Tank vs Tank Battle on a Realistic Terrain

A computer simulation model of a tank vs tank battle scenario was earlier developed and programmed on PRIME-750. The model has been refined and improved further in terms of organisation, terrain and tactics. The present paper describes the following features, which have been incorporated into the model : (a) units in formation (b) physical terrain features in the form of sand dunes (c) tactical manoeuvres and (d) real-time graphic display of the whole combat action. In accordance with the scenario, improved criteria for manoeuvres bypassing obstacles, search and fire have been introduced

Networks in cognitive science

Networks of interconnected nodes have long played a key role in Cognitive Science, from artificial neural networks to spreading activation models of semantic memory. Recently, however, a new Network Science has been developed, providing insights into the emergence of global, system-scale properties in contexts as diverse as the Internet, metabolic reactions, and collaborations among scientists. Today, the inclusion of network theory into Cognitive Sciences, and the expansion of complex-systems science, promises to significantly change the way in which the organization and dynamics of cognitive and behavioral processes are understood. In this paper, we review recent contributions of network theory at different levels and domains within the Cognitive Sciences.Postprint (author's final draft

Neorogioltriol: A brominated diterpene with analgesic activity from Laurencia glandulifera

International audienceThe new tricyclic brominated diterpenoid, neorogioltriol (1), was isolated from the organic extract of the red alga Laurencia glandulifera, collected at Kefalonia Island in Western Greece. Assignment of the (1)H and (13)C NMR resonances were carried out by extensive analysis of its NMR spectra. The new metabolite was evaluated for its analgesic activity using the writhing test in mice and the formalin test in rats. A dose-dependant antiinociceptive response was observed in the writhing test at 0.5 and 1 mg/kg with an IC(50) of 12.5 mu g/kg. Compound 1 also inhibited the second phase of the formalin test. (c) 2008 Phytochemical Society of Europe Published by Elsevier B.V. All rights reserved

In Vivo and in Vitro Anti-Inflammatory Activity of Neorogioltriol, a New Diterpene Extracted from the Red Algae Laurencia glandulifera

Neorogioltriol is a tricyclic brominated diterpenoid isolated from the organic extract of the red algae Laurencia glandulifera. In the present study, the anti-inflammatory effects of neorogioltriol were evaluated both in vivo using carrageenan-induced paw edema and in vitro on lipopolysaccharide (LPS)-treated Raw264.7 macrophages. The in vivo study demonstrated that the administration of 1 mg/kg of neorogioltriol resulted in the significant reduction of carregeenan-induced rat edema. In vitro, our results show that neorogioltriol treatment decreased the luciferase activity in LPS-stimulated Raw264.7 cells, stably transfected with the NF-κB-dependent luciferase reporter. This effect on NF-κB activation is not mediated through MAPK pathways. The inhibition of NF-κB activity correlates with decreased levels of LPS-induced tumor necrosis factor-alpha (TNFα) present in neorogioltriol treated supernatant cell culture. Further analyses indicated that this product also significantly inhibited the release of nitric oxide and the expression of cyclooxygenase-2 (COX-2) in LPS-stimulated Raw264.7 cells. These latter effects could only be observed for neorogioltriol concentrations below 62.5 μM. To our knowledge, this is the first report describing a molecule derived from Laurencia glandulifera with anti-inflammatory activity both in vivo and in vitro. The effect demonstrated in vitro may be explained by the inhibition of the LPS-induced NF-κB activation and TNFα production. NO release and COX-2 expression may reinforce this effect

Spatial and temporal analysis of heavy metals in surface waters, bed sediments and suspended sediments of the River Stour, East Kent, U.K.

A baseline study has been undertaken to assess the environmental impact of heavy metals within the fluvial environment of the River Stour, E. Kent, U.K. The occurrence of metal enrichment in surface waters and bed sediments coincides mainly with areas of urbanisation and high density traffic in addition to point source discharges including STW and industrial effluent outlets. Non-tidal surface water samples exhibiting Pb, Co, Cu, Fe and Zn concentrations intermittently elevated above EQS List I and II values largely correspond with bed sediment samples exhibiting metal concentrations above background values and commonly partitioned to the mobile exchangeable/acid soluble and reducible fractions. In the tidal reaches surface water samples exhibiting As, Cd, Co, Cu, Cr, Ni, Pb, V and Zn concentrations above EQS List I and II values are generally associated with bed sediment samples exhibiting partitioning to the immobile oxidisable fraction, suggesting that estuarine processes effectively promote the liberation of elements from the sediment compartment to surface waters. Total catchment annual suspended sediment yield, (190 t/km2/yr), is consistent with previous research work detailing the annual yield of U.K. rivers which in conjunction with suspended sediment concentration data highlights the importance of the transport and distribution of associated elements throughout the river system. Research highlights a requirement to improve point source management measures and control non-point sources and dredging activities and provides an index in which to assess the future impact of anthropogenic sources of metals to the fluvial environment of the River Stour