Ad hoc networks are multihop wireless networks without fixed infrastructure, whose topology changes frequently and unpredictably. How to issue routes in such networks with sufficient and constant bandwidth is a key problem for some real-time services like audio and video services. This paper proposes a novel QoS solution using code division multiple access (CDMA) scheme, named CDMA Bus Lane, wh...

Understanding the physical behavior of polymer-based lubricants on the nanoscale is of critical importance to a myriad of engineering applications and devices. We have used molecular dynamics simulations to quantitatively evaluate the physical mechanisms underlying perfluoropolyether lubricant spreading on a solid substrate. We quantify the effect of molecular mass, molecule length, and lubrica...

the developing turbulent flow in an open channel is a complex three-dimensional flow influenced by the secondary currents and free surface effects and is, therefore, not amenable to analytical solution. this paper aims to study the impact of three key hydraulic parameters (relative roughness, the froude number and the reynolds number) on the establishment length using computational fluid dynami...

Abstruct-This paper presents a random spreading code assignment scheme for enhancing channel efficiency in centralized DS-SS packet radio networks which employ a multiple-capture receiver for each code channel. Compared to the common code case, this approach requires modest increase in receiver complexity, but the number of distinct spreading codes being used is considerably less than the numbe...

In this paper, two upper bounds on the achievable code rate of linear block codes for multiple phased-burst correction (MPBC) are presented. One bound is constrained to a maximum correctable cyclic burst length within every subblock, or equivalently a constraint on the minimum error free length or gap within every phased-burst. This bound, when reduced to the special case of a bound for single ...

The Lebesgue spectrum filter (LSF), a finite impulse response (FIR) filter whose coefficients decay exponentially with a negative factor r := √3 − 2, is shown to be effective preprocessing for spreading code in asynchronous code-division multiple-access (CDMA) systems. The LSF has only been studied independently from the well-known minimum mean-square error (MMSE) filter, an optimal FIR filter ...

Deene the Hill operator T = ?d 2 =dx 2 + q(x) in L 2 (R) and suppose q 2 L 2 (0; 1) is a 1-periodic real potential, R 1 0 q(x)dx = 0: We prove the estimate kqk 6 2kk(1 + kk 1=3); where kk 2 = P n>1 j n j 2 and j n j > 0; n > 1; is the gap length of T.

This paper describes a newly discovered aspect of T-codes, a family of variable length codes first described by Titchener in the 1980s. We show that the constant-length subsets of codewords generated during the Tcode construction process constitute sets of necklaces. Moreover, we show that these sets are complete except for a small subset which we characterize. Bounds on the number of constant-...

We investigate the maximum coding rate achievable on a two-user broadcast channel for the case where a common message is transmitted with feedback using either fixed-blocklength codes or variable-length codes. For the fixed-blocklength-code setup, we establish nonasymptotic converse and achievability bounds. An asymptotic analysis of these bounds reveals that feedback improves the second-order ...