In this paper, a new technique for characterization of digital-to-analog converters (DAC) used in wideband applications is described. Unlike the standard narrowband approach, this technique employs Least Square Estimation to characterize the DAC from dc to any target frequency. Characterization is performed using a random sequence with certain temporal and probabilistic characteristics suitable for intended operating conditions. The technique provides a linear estimation of the system and decomposes nonlinearity into higher-order harmonics and deterministic periodic noise. The technique can also be used to derive the impulse response of the converter, predict its operating bandwidth, and provide far more insight into its sources of distortion.
Abstract Objective Primary Sjögren's syndrome (SS) may lead to lymphoproliferative disease (LPD) and death in certain patients. We sought to determine the incidence and predictors of adverse long‐term outcomes to achieve a rational predictive classification of the syndrome. Methods Predictive modeling was performed in a cohort of 723 consecutive patients with primary SS (587 newly diagnosed [incident] cases and 136 prevalent cases). Results During 4,384 person‐years of followup, we recorded 39 deaths (7 due to lymphoma) and 38 diagnoses of LPD. The standardized mortality ratio was 1.15 (95% confidence interval [95% CI] 0.86–1.73) compared with the general population of Greece. In incident cases, the probability of LPD was 2.6% at 5 years and 3.9% at 10 years. Mortality rates were significantly higher in patients with low C4 levels at the first study visit (hazard ratio [HR] 4.39, 95% CI 2.18–8.83). LPD was independently predicted by the presence of parotid enlargement (HR 5.21, 95% CI 1.76–15.4), palpable purpura (HR 4.16, 95% CI 1.65–10.5), and low C4 levels (HR 2.40, 95% CI 0.99–5.83) at the first study visit. All patients who eventually developed lymphoma resulting in death during the followup period had either low C4 levels or palpable purpura at the first study visit. Training‐validation split‐cohort modeling confirmed the predictive importance of low C4 levels and palpable purpura, both of which were present in 20.9% of patients at their first visit. Conclusions In patients with primary SS, 1 in 5 deaths is attributable to lymphoma. The presence of palpable purpura and low C4 levels at the first visit adequately distinguishes high‐risk patients (type I primary SS) from patients with an uncomplicated disease course (type II [low‐risk] primary SS).
Time division multiplexing (TDM) must be employed in multi-Gb/s transceivers in order to overcome onchip clock frequency limitations. This paper describes a transmit pre-emphasis filter for a multi-level transceiver making use of TDM. The possible applications of such a transceiver include serial links and chip-to-chip communication. The requirement of very low probability of error in the absence of coding, and the need for an adaptive solution impose a peak transmit power constraint. The TDM system is mapped to a multiple-input-multiple-output (MIMO) system, and the noise sources are analyzed. The design of the pre-emphasis filter is shown to be a non-convex optimization problem, whose optimal solution is very difficult to obtain. Still, sub-optimal solutions are derived in closed form and adaptive implementations are described. Simulation results using parameters obtained from an experimental testbed indicate that these sub-optimal solutions actually achieve very good performance.
The design of a RISC processor requires a careful analysis of the tradeoffs that can be made between hardware complexity and software. As new generations of processors are built to take advantage of more advanced technologies, new and different tradeoffs must be considered. We examine the design of a second generation VLSI RISC processor, MIPS-X.
FPGA performance is limited mainly by the delay of the programmable interconnection network. This delay increases quadratically with the number of series switches, and is a problem especially when the programmable switches are implemented using MOS transistors, since these have an appreciable resistance and capacitance. The delay can be reduced, at the cost of routability, by limiting the number of series switches per interconnection, or at the cost of area by inserting repeaters. Conventional bidirectional repeaters consist of sets of unidirectional tristate buffers and memory cells. Their benefit is limited due to high area and delay penalty. Area and delay penalty can be alleviated by using a regenerative feedback that senses the beginning of a transition and subsequently enforces it. This requires one buffer and no memory cells. This article shows a network with such repeaters for direction-independent buffering.
Journal Article Reproducibility: Has Cancer Biology Failed beyond Repair? Get access John P A Ioannidis John P A Ioannidis Departments of Medicine, Epidemiology and Population Health, Biomedical Data Science, Statistics, and Meta-Research Innovation Center at Stanford (METRICS), Stanford University, Stanford, CA, USA Address correspondence to this author at: SPRC, 1265 Welch Rd, Medical School Office Building Room X306, Stanford, CA 94305, USA. E-mail: jioannid@stanford.edu. Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 68, Issue 8, August 2022, Pages 1005–1007, https://doi.org/10.1093/clinchem/hvac030 Published: 09 March 2022 Article history Received: 02 February 2022 Accepted: 08 February 2022 Published: 09 March 2022
Many biases affect scientific research, causing a waste of resources, posing a threat to human health, and hampering scientific progress. These problems are hypothesized to be worsened by lack of consensus on theories and methods, by selective publication processes, and by career systems too heavily oriented toward productivity, such as those adopted in the United States (US). Here, we extracted 1,174 primary outcomes appearing in 82 meta-analyses published in health-related biological and behavioral research sampled from the Web of Science categories Genetics & Heredity and Psychiatry and measured how individual results deviated from the overall summary effect size within their respective meta-analysis. We found that primary studies whose outcome included behavioral parameters were generally more likely to report extreme effects, and those with a corresponding author based in the US were more likely to deviate in the direction predicted by their experimental hypotheses, particularly when their outcome did not include additional biological parameters. Nonbehavioral studies showed no such “US effect” and were subject mainly to sampling variance and small-study effects, which were stronger for non-US countries. Although this latter finding could be interpreted as a publication bias against non-US authors, the US effect observed in behavioral research is unlikely to be generated by editorial biases. Behavioral studies have lower methodological consensus and higher noise, making US researchers potentially more likely to express an underlying propensity to report strong and significant findings.
Article Free Access Share on Using partitioning to help convergence in the standard-cell design automation methodology Authors: Hema Kapadia Computer Systems Lab, Stanford University, Stanford, CA Computer Systems Lab, Stanford University, Stanford, CAView Profile , Mark Horowitz Computer Systems Lab, Stanford University, Stanford, CA Computer Systems Lab, Stanford University, Stanford, CAView Profile Authors Info & Claims DAC '99: Proceedings of the 36th annual ACM/IEEE Design Automation ConferenceJune 1999 Pages 592–597https://doi.org/10.1145/309847.310005Online:01 June 1999Publication History 7citation215DownloadsMetricsTotal Citations7Total Downloads215Last 12 Months4Last 6 weeks2 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF
