We develop distributed algorithms for self-organizing sensor networks that respond to directing a target through a region. The sensor network models the danger levels sensed across its area and has the ability to adapt to changes. It represents the dangerous areas as obstacles. A protocol that combines the artificial potential field of the sensors with the goal location for the moving object guides the object incrementally across the network to the goal, while maintaining the safest distance to the danger areas. We give the analysis to the protocol and report on hardware experiments using a physical sensor network consisting of Mote sensors.

Highly correlated ab initio molecular orbital methodologies have been used in the study of substituent effects on the singlet−triplet gaps of a series of nitrenium ions and their corresponding isoelectronic carbenes. Calculations in solution were carried out with the isodensity polarizable continuum models, IPCM. The results show a net stabilization of the singlet species as a result of electronic density donation of the substituents to a vacant p orbital located in the central atom. It is shown that this “π-donor−π-acceptor” dependence of the singlet−triplet gap is more significant in the case of the nitrenium ions, due to the presence of a positive charge. In addition, it was found that the singlet−triplet gaps decrease with the polarity of the solvent, most likely due to stabilizing electrostatic interactions between the solvent and the charge distribution of the singlet.