| This paper investigates coding aspects in an OFDM-CDMA environment. The inherent bandwidth expansion in CDMA systems offers many possibilities for the application of powerful codes with low code rates. Three different coding strategies are under consideration: the combination of convolutional and repetition codes (conventional DS-CDMA system), a code-spread system consisting of one very low r...

Direct-sequence code-division multiple-access (DS-CDMA) signals are often regarded as a result of the multiplication of the data bits by a spreading sequence, which is clocked at a higher rate than the data sequence (where the ratio of the rates is the spreading factor), cf. figure 1 a. A conceptually different, but equivalent, description is that the symbol rate is raised by up-sampling (repet...

Designing structures that have minimal or zero coefficients of thermal expansion (CTE) are useful in many engineering applications. Zero thermal expansion is achievable with the design of porous materials. The behavior is primarily stretch-dominated, resulting in favorable stiffness. Two and three-dimensional lattices are designed using ribs consisting of straight tubes containing two nested sh...

Robots promise to enhance minimally-invasive surgery, but flexion of the thin instrument shaft introduces error into models of the robot kinematics. Visual or electromagnetic tracking of the instrument tip provides correct forward kinematics, but uncertainty in shaft bending and port location leaves residual errors in inverse kinematics. These errors can cause incorrect motions that preclude th...

We calculate the leading order anomalous dimension of the transversity structure function directly using three different methods, the local light–cone expansion in the forward case, the non–forward case, and the short–distance expansion of the forward Compton amplitude. Our results agree with the original calculation by Artru and Mekhfi [Z. Phys. 45 (1990) 669], which has been doubted recently....

We calculate the leading order anomalous dimension of the transversity structure function directly using three different methods, the local light–cone expansion in the forward case, the non–forward case, and the short–distance expansion of the forward Compton amplitude. Our results agree with the original calculation by Artru and Mekhfi [Z. Phys. 45 (1990) 669], which has been doubted recently....

The objective of this study was to explore the joint kinetics of upper extremities during wheelchair maneuvers. A high incidence of musculoskeletal injuries has been reported due to the overuse and high repetitive motion of wrist, elbow and shoulder during wheelchair propulsion. Studies have been conducted with the use of a dynamometer or treadmill to simulate propulsion on level or inclined su...

resonator model For modeling purposes, the MR is decomposed into two bent-straight waveguide couplers, represented by the blocks (I) and (II), which are connected to each other by two segments of the cavity. The external connections are provided by straight waveguides. Here we consider only forward propagating modes of uniform polarization. We assume that all elements are linear and that the ba...

A novel discrete singular convolution (DSC)  formulation  is  presented for the seepage analysis in irregular geometric porous media. The DSC is a new promising numerical approach which has been recently applied to solve several engineering problems. For a medium with regular geometry, realizing of the DSC for the seepage analysis is straight forward. But DSC implementation for a medium with ir...