3,898 research outputs found
Simplified Frame and Symbol Synchronization for 4–CPFSK with h=0.25
This paper examines the problem of rapid frame and symbol synchronization techniques intended particularly for constant envelope modulation formats M–CPFSK with modulation index h=1/M which are used in strictly bandwidth limited narrowband industrial applications. The data aided and non data aided versions of the algorithm based on digital frequency discrimination are discussed and compared against the synchronization techniques found in literature. Sample wise pattern correlation technique for joint frame and symbol synchronization is also studied. With the focus on a practical digital implementation the advantages and disadvantages of the described approaches are discussed
Implementation of Industrial Narrow Band Communication System into SDR Concept
The rapid expansion of the digital signal processing has penetrated recently into a sphere of high performance industrial narrow band communication systems which had been for long years dominated by the traditional analog circuit design. Although it brings new potential to even increase the efficiency of the radio channel usage it also forces new challenges and compromises radio designers have to face. In this article we describe the design of the IF sampling industrial narrowband radio receiver, optimize a digital receiver structure implemented in a single FPGA circuit and study the performance of such radio receiver architecture. As an evaluation criterion the communication efficiency in form of maximum usable receiver sensitivity, co-channel rejection, adjacent channel selectivity and radio blocking measurement have been selected
Validation of the German Revised Addenbrooke's Cognitive Examination for Detecting Mild Cognitive Impairment, Mild Dementia in Alzheimer's Disease and Frontotemporal Lobar Degeneration
Background/Aims: The diagnostic accuracy of the German version of the revised Addenbrooke's Cognitive Examination (ACE-R) in identifying mild cognitive impairment (MCI), mild dementia in Alzheimer's disease (AD) and mild dementia in frontotemporal lobar degeneration (FTLD) in comparison with the conventional Mini Mental State Examination (MMSE) was assessed. Methods: The study encompasses 76 cognitively healthy elderly individuals, 75 patients with MCI, 56 with AD and 22 with FTLD. ACE-R and MMSE were validated against an expert diagnosis based on a comprehensive diagnostic procedure. Statistical analysis was performed using the receiver operating characteristic method and regression analyses. Results: The optimal cut-off score for the ACE-R for detecting MCI, AD, and FTLD was 86/87, 82/83 and 83/84, respectively. ACE-R was superior to MMSE only in the detection of patients with FTLD {[}area under the curve (AUC): 0.97 vs. 0.92], whilst the accuracy of the two instruments did not differ in identifying MCI and AD. The ratio of the scores of the memory ACE-R subtest to verbal fluency subtest contributed significantly to the discrimination between AD and FTLD (optimal cut-off score: 2.30/2.31, AUC: 0.77), whereas the MMSE and ACE-R total scores did not. Conclusion: The German ACE-R is superior to the most commonly employed MMSE in detecting mild dementia in FTLD and in the differential diagnosis between AD and FTLD. Thus it might serve as a valuable instrument as part of a comprehensive diagnostic workup in specialist centres/clinics contributing to the diagnosis and differential diagnosis of the cause of dementia. Copyright (C) 2010 S. Karger AG, Base
Anodic dissolution of metals in oxide-free cryolite melts
The anodic behavior of metals in molten cryolite-alumina melts has been investigated mostly for use as inert anodes for the Hall-Héroult process. In the present work, gold, platinum, palladium, copper, tungsten, nickel, cobalt and iron metal electrodes were anodically polarized in an oxide-free cryolite melt (11%wt. excess AlF3 ; 5%wt. CaF2) at 1273 K. The aim of the experiments was to characterize the oxidation reactions of the metals occurring without the effect of oxygen-containing dissolved species. The anodic dissolution of each metal was demonstrated, and electrochemical reactions were assigned using reversible potential calculation. The relative stability of metals as well as the possibility of generating pure fluorine is discussed
Clinical and genetic analysis of 29 Brazilian patients with Huntington’s disease-like phenotype
Huntington’s disease (HD) is a neurodegenerative disorder characterized by chorea,
behavioral disturbances and dementia, caused by a pathological expansion of the CAG
trinucleotide in the HTT gene. Several patients have been recognized with the typical HD
phenotype without the expected mutation. The objective of this study was to assess the
occurrence of diseases such as Huntington’s disease-like 2 (HDL2), spinocerebellar ataxia
(SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and choreaacanthocytosis
(ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group
analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not
reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in
the group analyzed, and is attributable to the African ancestry of this population. However,
the etiology of the disease remains undetermined in the majority of the HD negative
patients with HD-like phenotype.
Key words: Huntington’s disease, Huntington’s disease-like, chorea-acanthocytosis,
Huntington’s disease-like 2
Simulation of Heavily Irradiated Silicon Pixel Sensors and Comparison with Test Beam Measurements
Charge collection measurements performed on heavily irradiated p-spray DOFZ
pixel sensors with a grazing angle hadron beam provide a sensitive
determination of the electric field within the detectors. The data are compared
with a complete charge transport simulation of the sensor which includes signal
trapping and charge induction effects. A linearly varying electric field based
upon the standard picture of a constant type-inverted effective doping density
is inconsistent with the data. A two-trap double junction model implemented in
the ISE TCAD software can be tuned to produce a doubly-peaked electric field
which describes the data reasonably well. The modeled field differs somewhat
from previous determinations based upon the transient current technique. The
model can also account for the level of charge trapping observed in the data.Comment: 8 pages, 11 figures. Talk presented at the 2004 IEEE Nuclear Science
Symposium, October 18-21, Rome, Italy. Submitted to IEEE Transactions on
Nuclear Scienc
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