AuthorHicks, William T.
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RightsCopyright © International Foundation for Telemetering
Collection InformationProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.
AbstractThe traditional use of active RC-type filters as anti-aliasing filters in Pulse Code Modulation (PCM) systems is being replaced by the use of Digital Signal Processing (DSP) filters, especially when performance requirements are tight and when operation over a wide environmental temperature range is required. In order to keep systems more flexible, it is often desired to let the DSP filters run asynchronous to the PCM sample clock. This results in the PCM output signal being a sampling of the output of the DSP, which is itself a sampling of the input signal. In the analysis of the PCM data, the signal will have a periodic repeat of a previous sample, or a missing sample, depending on the relative sampling rates of the DSP and the PCM. This paper analyzes what effects can be expected in the analysis of the PCM data when these anomalies are present. Results are presented which allow the telemetry engineer to make an effective value judgment based on the type of filtering technology to be employed and on the desired system performance.
SponsorsInternational Foundation for Telemetering
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What’s in your sample closet? A cross-sectional study to quantify the number of expired samples and to evaluate novelty and usefulness of sample closet medicationsEvans, Kari; The University of Arizona College of Medicine - Phoenix; Brown, Steven, MD (The University of Arizona., 2013-03)Background Many physicians dispense drug samples in their offices. In general, evidence suggests that drug samples provide minimal benefit to patients. Objective and Hypothesis To quantify the number of expired sample closet medications and to analyze the medications most commonly found for their novelty and usefulness. We hypothesized that the medications found in local sample closets will often be expired and will not be novel or useful. Methods We inventoried ten sample closets in primary care clinics. We quantified the number of expired medications and analyzed the 23 medications found in seven or more closets. To assess novelty, we determined if the sample medication: had a new mechanism of action, had a generic on market with same mechanism of action, and had a generic medication on market for the same indication. To assess usefulness, we determined if the sample medication had improved patient oriented outcomes, safety, and tolerability. We noted the cost of a one-month supply for the typical starting dose of each sample medication. Results Of the 12,581 drug packages and boxes we inventoried, 14% of were expired. Ninety-six percent (n=22) of sample closet medications had a generic medication on the market for the same indication and 74% (n=17) had a generic medication on the market with the same mechanism. Only 3 medications (13%) had evidence of superior patient oriented outcomes when compared to other medications for the same indication. Six medications (26%) demonstrated superior safety and tolerability. Only one medication (4%) was recommended as first line therapy in an evidence-based guideline. The mean cost for a one month supply of a typical starting dose was 178 dollars. Significance and Conclusions. Sample closet medications are often expired, have limited novelty and usefulness, and are expensive. The widespread use of sample medications should be re-examined.
Mechanics of sampling disturbances in clay soils.Wu, Chang-Shiou. (The University of Arizona., 1991)This research provides an insight into the quality of a soil sample during the penetration of a soil sampler. The investigation of the mechanical disturbances in a clay soil is conducted by using an updated Lagrangian finite element formulation with the 2nd Piola-Kirchhoff stress rate (the Truesdell stress increment) to account for the large deformation behavior near the sampling tube. The penetration of the sampler is simulated by spliting a group of nodes ahead of the penetration route up to a sufficient depth and applying incremental deformation to match the geometric configuration of the sampling tube. Consolidation effect is included to account for the rate of penetration. Thin-layer elements are added into the inside wall of the sampling tube to model the soil-sampler interface. The modified Cam-clay model is used to simulate the behavior of the soils. An experimental study was conducted to study the variations of stresses and pore water pressures at the soil-sampler interface. The numerical results show that (1) soil samples are subjected to three distinct stages of vertical strain history, compression-extension-recompression. The first stage of compression, in particular, causes irrecoverable changes in the virgin soil properties of the soil; (2) the undrained shear strength of a disturbed sample reconsolidated to the in situ stress condition is larger than the virgin soil for normally consolidated soils but it is smaller for over consolidated soils; (3) the sampling disturbances due to friction at the soil-sampler interface increase as the sampler penetrates the soil. As a result, long samples will be seriously degraded; (4) the increase of the rate of penetration can reduce the degree of disturbances; (5) the piston sampler induces much larger disturbances than the open-drive sampler.