A new coercivity estimate on the spectral gap of the linearized Boltzmann collision operator for multiple species is proved. The assumptions on the collision kernels include hard and Maxwellian potentials under Grad’s angular cut-off condition. Two proofs are given: a non-constructive one, based on the decomposition of the collision operator into a compact and a coercive part, and a constructiv...

We measure the perpendicular-to-parallel collision rate nu perpendicular parallel in laser-cooled magnetized ion plasmas, spanning the uncorrelated to correlated regimes. In correlated regimes, we measure collision rates consistent with the "Salpeter correlation enhancement" of roughly exp(Gamma), for correlation parameters Gamma less, similar 4. This enhancement also applies to fusion in dense...

Collision prediction is a fundamental operation for planning motion in dynamic environment. Existing methods usually exploit complex behavior models or use dynamic constraints in collision prediction. However, these methods all assume simple geometry, such as disc, which significantly limit their applicability. This paper proposes a new approach that advances collision prediction beyond disc ro...

Collision detection is a fundamental geometric tool for sampling-based motion planners. On the contrary, collision prediction for the scenarios that obstacle’s motion is unknown is still in its infancy. This paper proposes a new approach to predict collision by assuming that obstacles are adversarial. Our new tool advances collision prediction beyond the translational and disc robots; arbitrary...

We study collisional loss rates due to spin-exchange collisions in very-low-intensity Rb magneto-optical traps. The loss rate exhibits an unpredicted intensity dependence for low intensities, accounting for a large disparity between loss rates observed in light-force traps and magnetically confined Bose condensates. Possible collision mechanisms considered include light-altered collision phase ...

This paper presents an algorithm of hybrid collision detection. Firstly, the algorithm establishes sphere and OBB level bounding box for every model in virtual scene and then uses intersect test of sphere bounding box to exclude not intersect model. Between two model of maybe the intersection, it uses not intersect part of intersect test excluding model of OBB bounding box, reducing PSO searchi...

Rate adaptation is a link layer mechanism critical to the system performance by exploiting the multiple transmission rates provided by current IEEE 802.11 WLANs. The key challenge for designing such an algorithm is how to select the most appropriate transmission rate under different environments. The first generation rate adaptation schemes perform poorly in a collision dominant environment bec...

BACKGROUND There is no universally accepted definition of "contact" or "collision" sports in the literature. The few available studies evaluating contact and collision sports consider them to be synonymous. However, athletes in collision sports purposely hit or collide with each other or with inanimate objects with greater force and frequency than in contact sports, which could jeopardize funct...

A highly collision-resistive RFID system multiplexes communications between thousands of tags and a single reader in combination with time-domain multiplexing code division multiple access (TDCDMA), CRC error detection, and re-transmission for error recovery. The collision probability due to a random selection of CDMA codes and TDMA channels bounds the number of IDs successfully transmitted to ...

Unlike FEM (Finite Element Method), which provides an accurate deformation of soft objects, FFD (Free Form Deformation) based methods have been widely used for a quick and responsive representation of deformable objects in real-time applications such as computer games, animations, or simulations. The FFD-AABB (Free Form Deformation Axis Aligned Bounding Box) algorithm was also suggested to addr...