We show that if T is a bounded linear operator on a complex Hilbert space, then 1 2 ‖T‖ ≤ √ w2(T ) 2 + w(T ) 2 √ w2(T )− c2(T ) ≤ w(T ), where w(·) and c(·) are the numerical radius and the Crawford number, respectively. We then apply it to prove that for each t ∈ [0, 12 ) and natural number k, (1 + 2t) 1 2k 2 1 k m(T ) ≤ w(T ), where m(T ) denotes the minimum modulus of T . Some other related ...

In this paper, we consider blind estimation of linear chip-spaced receivers for the demodulation of a particular short-code DS-CDMA mobile user under multipath propagation and in the absence of timing information. We propose a family of schemes for blind acquisition and equalization based on Donoho's Minimum Entropy principle and propose a speciic algorithm that uses the second-and fourth-order...

The paper presents a modified least squares despread respread multitarget constant modulus algorithm (LS-DRMTCMA). The cost function of the original algorithm was modified by the minimum bit error rate (MBER) criterion. The novel algorithm tries to optimize weight vectors by directly minimizing bit error rate (BER) of code division multiple access (CDMA) mobile communication system. In order to...

In this paper, we consider blind estimation of linear chip-spaced receivers for the demodulation of a particular short-code DS-CDMA mobile user under multipath propagation and in the absence of timing information. We propose a family of schemes for blind acquisition and equalization based on Donoho's Minimum Entropy principle and propose a speciic algorithm that uses the second-and fourth-order...

This paper reviews the Super-exponential algorithm proposed by Shalvi and Weinstein for blind channel equalization. We show that the algorithm coincides with a gradient search of a maximum of a cost function, which belongs to a family of functions very relevant in blind channel equalization. This family traces back to Donoho’s work on minimum entropy deconvolution, and also underlies the Godard...

A Newman polynomial is a polynomial in one variable whose coefficients are 0 or 1, and the length of a Newman polynomial is the number of coefficients that are 1. Several authors have asked about the highest minimum modulus of a length n Newman polynomial on the unit circle, but there remains a large gap between what has been conjectured and what has been proved. In this paper, we prove that fo...

A novel initialization scheme for a constant modulus algorithm RAKE (CMA-RAKE) receiver for frequency-selective fading asynchronous code-division multiple access (CDMA) channels is proposed. The solutions from the minimization of the constrained minimum output energy (CMOE) criterion are adopted as the initialization of the subsequent CMA receivers. The proposed receiver is proven to be near-fa...

We construct a Banach space operator T which is not E(T)subscalar but ‖(T − z)−1‖ ≤ (|z| − 1)−1 for |z| > 1 and m(T − z) ≥ const · (1 − |z|)3 for |z| < 1 (here m denotes the minimum modulus). This gives a negative answer to a variant of a problem of Laursen and Neumann. We also give a sufficient condition (in terms of growth of resolvent and of an analytic left inverse of T − z) implying that T...

We present a new way to construct de Sitter vacua in type IIB flux compactifications, in which moduli stabilization and D-term uplifting can be combined in a manner consistent with the supergravity constraints. Here, the closed string fluxes fix the dilaton and the complex structure moduli while perturbative quantum corrections to the Kähler potential stabilize the volume Kähler modulus in an A...

Reclaimed asphalt pavement (RAP) is one of the waste materials that highway agencies promote to use in new construction or rehabilitation of highways pavement. Since the use of RAP can affect the resilient modulus and other structural properties of flexible pavement layers, this paper aims to employ two different artificial neural network (ANN) models for modeling and evaluating the effects of ...