1,035 research outputs found
Non-uniform wordlength delay lines for FIR filters
When FIR filters are designed floating point arithmetic is generally used. However when implemented on hardware such as ASICs, fixed point arithmetic must be used to minimise cost and power requirements. Research to minimise hardware costs has mainly focused on the quantization effects of fixed point wordlengths for the coefficients, multipliers and adders of FIR filters, but with the actual data delays assigned a uniform wordlength and essentially not optimised. This paper proposes that the wordlengths of the delay line can be non-uniform with a minimal increase in quantization noise for parallel implementation of FIR filters where there are differences in the magnitudes of the coefficients. A non-uniform delay line allows hardware savings in terms of delay register wordlengths, delay signal wordlengths and multiplier wordlengths. Results for an FIR design are presented which demonstrate the hardware savingswhen using a non-uniform wordlength delay lin
Adaptive digital signal processing Java teaching tool
This publication presents a JAVA program for teaching the rudiments of adaptive digital signal processing (DSP) algorithms and techniques. Adaptive DSP is on of the most important areas of signal processsing, and provides the core algorithmic means to implement applications ranging from mobile telephone speech coding, to noise cancellation, to communication channel equalization. Over the last 30 years adaptive digital signal processing has progressed from being a strictly graduate level advanced class in signal processing theory to a topic that is part of the core curriculum for many undergraduate signal processing classes. The JAVA applet presented in this publication has been devised for students to use in combination with lecture notes and/or one of the recognised textbooks such that they can quickly and conveniently simulate algorithms such as the LMS (least mean squares), RLS (recursive least squares) and so on in a variety of applications without requiring to write programs or scripts or using any special purpose software. By the very nature of the JAVA code therefore, the applet can be run from any browser, even over a low bandwidth modem connection
Coverage and density of a low power, low data rate, spread spectrum wireless sensor network for agricultural monitoring
A physical layer specification for a low power, low complexity, low data rate sensor network suitable for agricultural monitoring is investigated. Code division multiple access (CDMA) with high processing gain is used to facilitate transmission powers which comply with the Ultra Wide Band (UWB) spectral mask, and this permits physically small nodes with limited energy storage capacity. The interference arising from each node is calculated, and it is shown that for the investigated scenario and specification, an aggregate data rate of 2 bytes per minute and a node population of approximately 1000 can be supported at distances up to a few kilometres from the central node, with less than 0.2% chance of failure due to multiple access interference
Hypertension in mice lacking 11beta-hydroxysteroid dehydrogenase type 2
Deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) in humans leads to the syndrome of apparent mineralocorticoid excess (SAME), in which cortisol illicitly occupies mineralocorticoid receptors, causing sodium retention, hypokalemia, and hypertension. However, the disorder is usually incompletely corrected by suppression of cortisol, suggesting additional and irreversible changes, perhaps in the kidney. To examine this further, we produced mice with targeted disruption of the 11β-HSD2 gene. Homozygous mutant mice (11β-HSD2(–/–)) appear normal at birth, but ∼50% show motor weakness and die within 48 hours. Both male and female survivors are fertile but exhibit hypokalemia, hypotonic polyuria, and apparent mineralocorticoid activity of corticosterone. Young adult 11β-HSD2(–/–) mice are markedly hypertensive, with a mean arterial blood pressure of 146 ± 2 mmHg, compared with 121 ± 2 mmHg in wild-type controls and 114 ± 4 mmHg in heterozygotes. The epithelium of the distal tubule of the nephron shows striking hypertrophy and hyperplasia. These histological changes do not readily reverse with mineralocorticoid receptor antagonism in adulthood. Thus, 11β-HSD2(–/–) mice demonstrate the major features of SAME, providing a unique rodent model to study the molecular mechanisms of kidney resetting leading to hypertension. J. Clin. Invest. 103:683–689 (1999
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Quality assurance plan for the Objective Supply Capability Adaptive Redesign (OSCAR) project
This document establishes the Quality Assurance Plan (QAP) for the National Guard Bureau Objective Supply Capability Adaptive Redesign (OSCAR) project activities under the Oak Ridge National Laboratory (ORNL) management. It defines the requirements and assigns responsibilities for ensuring, with a high degree of confidence, that project objectives will be achieved as planned. The QAP outlined herein is responsive to and meets the Quality Assurance Program standards for the U.S. Department of Energy (DOE), Lockheed Martin Energy Research Corporation and ORNL and the ORNL Computing, Robotics, and Education Directorate (CRE). This document is intended to be in compliance with DOE Order 5700.6C, Quality Assurance Program, and the ORNL Standard Practice Procedure, SPP X-QA-8, Quality Assurance for ORNL Computing Software. This standard allows individual organizations to apply the stated requirements in a flexible manner suitable to the type of activity involved. Section I of this document provides an introduction to the OSCAR project QAP; Sections 2 and 3 describe the specific aspects of quality assurance as applicable to the OSCAR project. Section 4 describes the project approach to risk management. The Risk Management Matrix given in Appendix A is a tool to assess, prioritize, and prevent problems before they occur. Therefore, the matrix will be reviewed and revised on a periodic basis
Multiband superconductivity in NbSe_2 from heat transport
The thermal conductivity of the layered s-wave superconductor NbSe_2 was
measured down to T_c/100 throughout the vortex state. With increasing field, we
identify two regimes: one with localized states at fields very near H_c1 and
one with highly delocalized quasiparticle excitations at higher fields. The two
associated length scales are most naturally explained as multi-band
superconductivity, with distinct small and large superconducting gaps on
different sheets of the Fermi surface.Comment: 2 pages, 2 figures, submitted to M2S-Rio 2003 Proceeding
Losing sight of Luck: Automatic approach tendencies toward gambling cues in Canadian moderate- to high-risk gamblers – A replication study
Evidence for approach bias tendencies to underly automatic behavioural impulses towards seeking out gambling activities in the presence of appetitive salient cues was first shown by Boffo et al. (2018) in a Dutch sample. Relative to non-problem gamblers, moderate-to-high-risk gamblers demonstrated stronger approach tendencies towards gambling-related stimuli compared with neutral ones. Moreover, gambling approach bias was associated with past-month gambling behaviour and predictive of gambling activity persistence over time. The current study aimed to replicate these findings within a Canadian sample evaluating the concurrent and longitudinal correlates of gambling approach bias. The study was conducted online, available throughout Canada. Twenty-seven non-treatment-seeking moderate-to-high-risk gamblers and 26 non-problem gamblers community-recruited via multiple channels (i.e., internet and newspaper advertisements, land-based flyers, and university recruitment portals). Participants completed two online assessment sessions 6-months apart. Each session included (1) self-report measures of gambling behaviour (frequency, duration, and expenditure), (2) self-report assessment of problem gambling severity (PGSI), and (3) a gambling approach-avoidance task, utilising culturally relevant stimuli tailored to individual gambling habits. However, our study failed to replicate Boffo et al. (2018) findings in a Canadian sample. Relative to non-problem gamblers, moderate-to-high-risk gamblers did not exhibit greater approach bias tendencies towards gambling-related stimuli compared to neutral stimuli. Moreover, gambling approach bias was not predictive of prospective gambling behaviour (frequency, duration, or expenditure) or severity of gambling problems. Reported results do not provide evidence for approach tendencies contributing to problematic gambling behaviour in a Canadian sample of moderate-to-high-risk gamblers compared to non-problematic gambler controls. Further replications on the topic are needed. Future research should evaluate approach tendencies within the gambling context, considering the potential impact of task reliability to assess approach bias in light of individual gambling modality preferences.</p
Smart wireless railway monitoring system
With the increased demand for railway services, train speed and density are consistently increasing in the last two decades. As a result, more strict safety requirements for railway signaling, control and infrastructure are needed. Accompanying that trend, in recent years, wireless communication techniques have also advanced rapidly. Especially with smart low cost wireless communication techniques like WIFI, Bluetooth, and ZigBee going into maturity, thus making it possible to develop a wireless system to monitor a railway's signaling or control or infrastructure condition. An effective low cost monitor system will help the normal function of railway systems. This paper gives a description of the development of one such monitoring system. The whole system consists of a remote controller and many monitor units. The remote controller gets data from the monitor units and sends control commands and monitoring control information to the monitor units. The paper will show how such a basic set up could be deployed for railway monitoring using wireless technology
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