In this paper we present Walsh-quadrature phase-shift keying (Walsh-QPSK) pseudonoise (PN) modulation schemes for both coherent and noncoherent direct-sequence code-division multiple-access (DS-CDMA) systems, wherein the PN spreading sequences for in-phase and quadrature data in a conventional QPSK PN modulation scheme are coded by Walsh sequences indexed by a special rule to reduce the envelop...

ntestinal failure (IF) is considered the end result of gastrointestinal disorders in which functional intestinal mass is inadequate to promote adequate growth, hydration, and electrolyte balance. Today, a substantial number of infants and children with IF, caused by short bowel syndrome, necrotizing enterocolitis, gastroschisis, intestinal atresias, motility disorders, and genetic enterocyte tr...

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-cod...

In this paper, we consider the noncoherent code acquisition problem using sequential schemes. Since code acquisition schemes using the maximum likelihood estimate usually require a high level of computational complexity, simplified schemes are proposed and analyzed based on approximations. The performance of the simplified and original code acquisition schemes are compared in additive white Gau...

We present a new model to explain the excess in mid and near infrared emission of the central, hydrogen poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurement because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations affecting infrared emission using a new radiative t...

Self-encoded spread spectrum eliminates the need for traditional pseudo noise (PN) code generators. In a self-encoded multiple access (SEMA) system, the number of users is not limited by the number of available sequences, unlike code division multiple access (CDMA) systems that employ PN codes such as m-, Gold or Kassami sequences. SEMA provides a convenient way of supporting multi-rate, multi-...

This paper compares the mean acquisition time performance of two serial search acquisition schemes over frequency-selective multipath Rayleigh fading channels. Both the conventional cell-by-cell detection and the novel joint twin-cell detection are characterised. In contrast to the majority of published results considering only one correct timing state (H1 cell) in the uncertainty region of the...

BACKGROUND Parenteral nutrition (PN) is a costly therapy that can also be associated with serious complications. Therefore, efforts are focusing on reducing rate of complications, and costs related to PN. OBJECTIVE The aim was to analyze the effect of the implementation of PN standardization on costs and quality criteria. Secondary aim was to assess the use of individualized PN based on patie...