Study On The Dead Reckoning Of Land Vehicles In A Distributed Interactive Simulation Environment

Report on study of dead-reckoning of a military tank in a distributed interactive simulation

Interconversions Between Different Coordinate Systems

A detailed study of geocentric, geodetic, and topocentric coordinate systems and coordinate conversion algorithms for them, including problems encountered in the conversions

"An Econometric Analysis of SARS and Avian Flu on International Tourist Arrivals to Asia"

This paper compares the impacts of SARS and human deaths arising from Avian Flu on international tourist arrivals to Asia. The effects of SARS and human deaths from Avian Flu will be compared directly according to human deaths. The nature of the short run and long run relationship is examined empirically by estimating a static line fixed effect model and a difference transformation dynamic model, respectively. Empirical results from the static fixed effect and difference transformation dynamic models are consistent, and indicate that both the short run and long run SARS effect have a more significant impact on international tourist arrivals than does Avian Flu. In addition, the effects of deaths arising from both SARS and Avian Flu suggest that SARS is more important to international tourist arrivals than is Avian Flu. Thus, while Avian Flu is here to stay, its effect is currently not as significant as that of SARS.

Effect of Na+ Flow on Cd2+ Block of Tetrodotoxin-resistant Na+ Channels

Tetrodotoxin-resistant (TTX-R) Na+ channels are 1,000-fold less sensitive to TTX than TTX-sensitive (TTX-S) Na+ channels. On the other hand, TTX-R channels are much more susceptible to external Cd2+ block than TTX-S channels. A cysteine (or serine) residue situated just next to the aspartate residue of the presumable selectivity filter “DEKA” ring of the TTX-R channel has been identified as the key ligand determining the binding affinity of both TTX and Cd2+. In this study we demonstrate that the binding affinity of Cd2+ to the TTX-R channels in neurons from dorsal root ganglia has little intrinsic voltage dependence, but is significantly influenced by the direction of Na+ current flow. In the presence of inward Na+ current, the apparent dissociation constant of Cd2+ (∼200 μM) is ∼9 times smaller than that in the presence of outward Na+ current. The Na+ flow–dependent binding affinity change of Cd2+ block is true no matter whether the direction of Na+ current is secured by asymmetrical chemical gradient (e.g., 150 mM Na+ vs. 150 mM Cs+ on different sides of the membrane, 0 mV) or by asymmetrical electrical gradient (e.g., 150 mM Na+ on both sides of the membrane, −20 mV vs. 20 mV). These findings suggest that Cd2+ is a pore blocker of TTX-R channels with its binding site located in a multiion, single-file region near the external pore mouth. Quantitative analysis of the flow dependence with the flux-coupling equation reveals that at least two Na+ ions coexist with the blocking Cd2+ ion in this pore region in the presence of 150 mM ambient Na+. Thus, the selectivity filter of the TTX-R Na+ channels in dorsal root ganglion neurons might be located in or close to a multiion single-file pore segment connected externally to a wide vestibule, a molecular feature probably shared by other voltage-gated cationic channels, such as some Ca2+ and K+ channels

Confidence-Level-Based New Adaptive Particle Filter for Nonlinear Object Tracking Regular Paper

Nonlinear object tracking from noisy measurements is a basic skill and a challenging task of mobile robotics, especially under dynamic environments. The particle filter is a useful tool for nonlinear object tracking with non-Gaussian noise. Nonlinear object tracking needs the real-time processing capability of the particle filter. While the number in a traditional particle filter is fixed, that can lead to a lot of unnecessary computation. To address this issue, a confidence-level-based new adaptive particle filter (NAPF) algorithm is proposed in this paper. In this algorithm the idea of confidence interval is utilized. The least number of particles for the next time instant is estimated according to the confidence level and the variance of the estimated state. Accordingly, an improved systematic re-sampling algorithm is utilized for the new improved particle filter. NAPF can effectively reduce the computation while ensuring the accuracy of nonlinear object tracking. The simulation results and the ball tracking results of the robot verify the effectiveness of the algorithm

A Cooperative Path Planning Algorithm for a Multiple Mobile Robot System in a Dynamic Environment

A practical path planning method for a multiple mobile robot system (MMRS) requires handling both the collision-free constraint and the kinematic constraint of real robots, the latter of which has to date been neglected by most path planning methods. In this paper, we present a practical cooperative path planning algorithm for MMRS in a dynamic environment. First, each robot uses an analytical method to plan an obstacle-avoidance path. Then, a distributed prioritized scheme is introduced to realize cooperative path planning. In the scheme, each robot calculates a priority value according to its situation at each instant in time, which will determine the robot\u27s priority. Higher-priority robots can ignore lower-priority robots, whereas lower-priority robots should avoid collisions with higher-priority robots. To minimize the path length for MMRS, a least path length constraint is added. The priority value is also calculated by a path cost function that takes the path length into consideration. Unlike other priority methods, the algorithm proposed is not time consuming; therefore, it is suitable for dynamic environments. Simulation results are presented to verify the effectiveness of the proposed algorithm