Home About us Contact
|
Home About us Contact | ||
|
|
||
Source Data (source + data)
Selected AbstractsSystematic unbalanced interharmonic interaction analysis with power constraintsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 1 2005Jesús C. Contreras Sampayo Abstract This paper presents a systematic technique to solve for the harmonic and interharmonic interaction between a power system and several harmonic sources. The technique can potentially analyze any power electronic source that can be modeled as a piece-wise linear circuit. Harmonic source data is input to the procedure using a standard lumped parameter description. Two test cases are presented. The first test case shows the interaction between a static var compensator (SVC) and an HVDC in unbalanced operating conditions. The second test case analyzes a complete current source variable speed drive connected to a distribution network. Both test cases include power constraints. Copyright © 2005 John Wiley & Sons, Ltd. [source] Distance separated simultaneous sweeping, for fast, clean, vibroseis acquisitionGEOPHYSICAL PROSPECTING, Issue 1 2010Jack Bouska ABSTRACT Distance separated simultaneous sweeping DS3 is a new vibroseis technique that produces independent records, uncontaminated by simultaneous source interference, for a range of offsets and depths that span all target zones of interest. Use of DS3 on a recent seismic survey in Oman, resulted in a peak acquisition rate of 1024 records per hour. This survey employed 15 vibrators, with a distance separation of 12 km between simultaneous active sources, recorded by 8000 active channels across 22 live lines in an 18.5 km × 11 km receiver patch. Broad distribution of simultaneous sources, across an adequately sized recording patch, effectively partitions the sensors so that each trace records only one of the simultaneous sources. With proper source separation, on a scale similar to twice the maximum usable source receiver offset, wavefield overlap occurs below the zone of interest. This yields records that are indistinguishable from non-simultaneous source data, within temporal and spatial limits. This DS3 technique may be implemented using a wide variety of acquisition geometries, optimally with spatially large recording patches that enable appropriate source separation distances. DS3 improves acquisition efficiency without data quality degradation, eliminating the requirement for special data processing or noise attenuation. [source] Source density-driven independent component analysis approach for fMRI dataHUMAN BRAIN MAPPING, Issue 3 2005Baoming Hong Abstract Independent component analysis (ICA) has become a popular tool for functional magnetic resonance imaging (fMRI) data analysis. Conventional ICA algorithms including Infomax and FAST-ICA algorithms employ the underlying assumption that data can be decomposed into statistically independent sources and implicitly model the probability density functions of the underlying sources as highly kurtotic or symmetric. When source data violate these assumptions (e.g., are asymmetric), however, conventional ICA methods might not work well. As a result, modeling of the underlying sources becomes an important issue for ICA applications. We propose a source density-driven ICA (SD-ICA) method. The SD-ICA algorithm involves a two-step procedure. It uses a conventional ICA algorithm to obtain initial independent source estimates for the first-step and then, using a kernel estimator technique, the source density is calculated. A refitted nonlinear function is used for each source at the second step. We show that the proposed SD-ICA algorithm provides flexible source adaptivity and improves ICA performance. On SD-ICA application to fMRI signals, the physiologic meaningful components (e.g., activated regions) of fMRI signals are governed typically by a small percentage of the whole-brain map on a task-related activation. Extra prior information (using a skewed-weighted distribution transformation) is thus additionally applied to the algorithm for the regions of interest of data (e.g., visual activated regions) to emphasize the importance of the tail part of the distribution. Our experimental results show that the source density-driven ICA method can improve performance further by incorporating some a priori information into ICA analysis of fMRI signals. Hum Brain Mapping, 2005. © 2005 Wiley-Liss, Inc. [source] Meta-analysis of the efficacy of the acetonic kava-kava extract WS®1490 in patients with non-psychotic anxiety disorders,PHYTOTHERAPY RESEARCH, Issue 3 2005Steffen Witte Abstract Introduction: The herbal medicinal product kava-kava, used for treating anxiety disorders, was assessed positively by the Cochrane Review. However, it was withdrawn from the market in Switzerland and Germany due to cases of liver failure and ,unproven' efficacy. Methods: A protocol for the meta-analysis based on patient source data was written, a literature search was done, and six placebo-controlled, randomized trials with the kava extract WS®1490 were identified. The endpoints were the change in HAMA during treatment (continuous and binary). Results: WS®1490 has an effective success rate of OR=3.3 (95% confidence interval of 2.09,5.22) in patients with non-psychotic anxiety disorders. The continuous outcome supports this result: mean improvement with WS®1490 by 5.94 (95% confidence interval ,0.86 to 12.8) points on the HAMA scale better than placebo. Kava seems to be more effective in females and in younger patients. Discussion: This meta-analysis has no publication bias, no remarkable heterogeneity and is based on trials with high methodological standards. It is concluded that WS®1490, and possibly other kava extracts, are effective. Therefore they remain alternatives to benzodiazepines, selective serotonin re-uptake inhibitors (SSRIs) and other antidepressants in the treatment of non-psychotic anxiety disorders. Copyright © 2005 John Wiley & Sons, Ltd. [source] Differences in clinical trial conduct in US and EU investigational sitesQUALITY ASSURANCE JOURNAL, Issue 1 2001Douglas R. Mackintosh Abstract Observations by clinical auditors about good clinical practice (GCP) compliance in US and EU investigational sites are described. Specific differences between the two regions are noted for institutional review boards (IRBs) and ethics committees; subject recruiting and consenting; investigator/study coordinator qualifications and functions; organization and recording of source data; health care delivery; quality of monitoring; and filing of regulatory documents. Neither region of the world demonstrated GCP superiority in the conduct of its clinical trials. Copyright © 2001 John Wiley & Sons, Ltd. [source] Former distribution and decline of the burbot (Lota lota) in the UKAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010T. Worthington Abstract 1.Species reintroductions are an increasingly fashionable tool among conservation practitioners for restoring locally and nationally extinct populations. For a reintroduction programme to be successful, an understanding of the causes of the decline of a species is required. This, however, proves challenging when baseline data on the distribution and abundance of the species are limited. 2.This paper uses evidence from historical literature to map the former distribution of the burbot (Lota lota) within UK rivers before its extinction in the early 1970s. A scoring system was developed to model anecdotal descriptions of burbot abundance from the collected literature. 3.The former distribution was divided into four geographical areas based loosely on catchment boundaries. The literature identifies 42 rivers in eastern England in which the burbot was likely to have existed. The status of the species in the Thames catchment is still unclear as information from written sources is contradicted by evidence from the archaeological record. 4.The findings indicate that the year of source data was a significant predictor of burbot abundance across the former population as a whole and for three of the four geographical areas (the Trent catchment, the Fenland rivers and the Yorkshire rivers). The timing of the burbot's decline showed differences between the geographical regions, with the Trent catchment exhibiting an earlier decline than the Fenland and Yorkshire areas. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||