IEEE802.15.4 is a standard designed for low rate wireless personal area network. For its MAC protocol adopts the competition method to share wireless channel, collisions between ending devices are unavoidable and lead to retransmissions, consuming more energy. As traffic load becomes heavier, collisions and retransmissions are more serious. The focus of this paper is to achieve dynamic-paramete...

This article reports the development of an unmanned aerial vehicle capable of attitude estimation and stabilization through the implementation of a nonlinear complementary filter and proportional-integral rate controllers. Four infra-red sensors and an ultrasonic sensor are integrated with the main platform for the collision avoidance schemes and for altitude control, respectively. Critical mis...

We investigate the electromagnetic signals accompanied with planetary collisions and their event rate, and explore the possibility of directly detecting such events. A typical Earth– Jupiter collision would give rise to a prompt EUV-soft-X-ray flash lasting for hours and a bright IR afterglow lasting for thousands of years. With the current and forthcoming observational technology and facilitie...

The implementation of surface-induced dissociation (SID) to study the fast dissociation kinetics (sub-microsecond dissociation) of peptides in a MALDI TOF instrument has been reported previously. Silicon nanoparticle assisted laser desorption/ionization (SPALDI) now allows the study of small molecule dissociation kinetics for ions formed with low initial source internal energy and without MALDI...

Collisional energy transfer of NH2 in its electronically excited state à A1 is investigated with time-resolved Fourier transform emission spectroscopy. NH2 is produced by photodissociation of NH3 and relaxed to low rotational levels before excitation into the electronically excited state. Originating from collisions with NH3 , rate constants for total collisional removal and state-to-state rate...

We study inelastic gases in two dimensions using event-driven molecular dynamics simulations. Our focus is the nature of the stationary state attained by rare injection of large amounts of energy to balance the dissipation due to collisions. We find that under such extreme driving, with the injection rate much smaller than the collision rate, the velocity distribution has a power-law high energ...

BACKGROUND Worldwide, injuries from road traffic collisions are a rapidly growing problem in terms of morbidity and mortality. The UK has amongst the worst records in Europe with regard to child pedestrian safety. A traditional view holds that resources should be directed towards training child pedestrians. In order to reduce socio-economic differentials in child pedestrian casualty rates it is...

A theoretical model for describing the initial stages of the aggregation of partially covered colloidal particles is presented. It is based on the assumption of short-range interactions that may be modeled by a sticking probability on contact. Three types of sticking probabilities are distinguished depending on the collision type, i.e., for bare-bare, bare-covered, and covered-covered collision...

In the present paper, we provide an analytical expression for the first- and second-order velocity slip coefficients by means of a variational technique that applies to the integrodifferential form of the Boltzmann equation based on the true linearized collision operator and the Cercignani-Lampis scattering kernel of the gas-surface interaction. The polynomial form of the Knudsen number obtaine...

BACKGROUND Collision geocoding is the process of assigning geographic descriptors, usually latitude and longitude coordinates, to a traffic collision record. On California police reports, relative collision location is recorded using a highway postmile marker or a street intersection. The objective of this study was to create a geocoded database of all police-reported, fatal and severe injury c...