WorldWideScience

Sample records for validated rct filter

  1. Validation of the REBUS-3/RCT methodologies for EBR-II core-follow analysis

    International Nuclear Information System (INIS)

    McKnight, R.D.

    1992-01-01

    One of the many tasks to be completed at EBR-2/FCF (Fuel Cycle Facility) regarding fuel cycle closure for the Integral Fast Reactor (IFR) is to develop and install the systems to be used for fissile material accountancy and control. The IFR fuel cycle and pyrometallurgical process scheme determine the degree of actinide of actinide buildup in the reload fuel assemblies. Inventories of curium, americium and neptunium in the fuel will affect the radiation and thermal environmental conditions at the fuel fabrication stations, the chemistry of reprocessing, and the neutronic performance of the core. Thus, it is important that validated calculational tools be put in place for accurately determining isotopic mass and neutronic inputs to FCF for both operational and material control and accountancy purposes. The primary goal of this work is to validate the REBUS-2/RCT codes as tools which can adequately compute the burnup and isotopic distribution in binary- and ternary-fueled Mark-3, Mark-4, and Mark-5 subassemblies. 6 refs

  2. The medline UK filter: development and validation of a geographic search filter to retrieve research about the UK from OVID medline.

    Science.gov (United States)

    Ayiku, Lynda; Levay, Paul; Hudson, Tom; Craven, Jenny; Barrett, Elizabeth; Finnegan, Amy; Adams, Rachel

    2017-07-13

    A validated geographic search filter for the retrieval of research about the United Kingdom (UK) from bibliographic databases had not previously been published. To develop and validate a geographic search filter to retrieve research about the UK from OVID medline with high recall and precision. Three gold standard sets of references were generated using the relative recall method. The sets contained references to studies about the UK which had informed National Institute for Health and Care Excellence (NICE) guidance. The first and second sets were used to develop and refine the medline UK filter. The third set was used to validate the filter. Recall, precision and number-needed-to-read (NNR) were calculated using a case study. The validated medline UK filter demonstrated 87.6% relative recall against the third gold standard set. In the case study, the medline UK filter demonstrated 100% recall, 11.4% precision and a NNR of nine. A validated geographic search filter to retrieve research about the UK with high recall and precision has been developed. The medline UK filter can be applied to systematic literature searches in OVID medline for topics with a UK focus. © 2017 Crown copyright. Health Information and Libraries Journal © 2017 Health Libraries GroupThis article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

  3. Validation of search filters for identifying pediatric studies in PubMed

    NARCIS (Netherlands)

    Leclercq, Edith; Leeflang, Mariska M. G.; van Dalen, Elvira C.; Kremer, Leontien C. M.

    2013-01-01

    To identify and validate PubMed search filters for retrieving studies including children and to develop a new pediatric search filter for PubMed. We developed 2 different datasets of studies to evaluate the performance of the identified pediatric search filters, expressed in terms of sensitivity,

  4. HEPA filter leaching concept validation trials at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Chakravartty, A.C.

    1995-04-01

    The enclosed report documents six New Waste Calcining Facility (NWCF) HEPA filter leaching trials conducted at the Idaho Chemical Processing Plant using a filter leaching system to validate the filter leaching treatment concept. The test results show that a modified filter leaching system will be able to successfully remove both hazardous and radiological constituents to RCRA disposal levels. Based on the success of the filter leach trials, the existing leaching system will be modified to provide a safe, simple, effective, and operationally flexible filter leaching system

  5. Content and Construct Validity, Reliability, and Responsiveness of the Rheumatoid Arthritis Flare Questionnaire

    DEFF Research Database (Denmark)

    Bartlett, Susan J; Barbic, Skye P; Bykerk, Vivian P

    2017-01-01

    -FQ), and the voting results at OMERACT 2016. METHODS: Classic and modern psychometric methods were used to assess reliability, validity, sensitivity, factor structure, scoring, and thresholds. Interviews with patients and clinicians also assessed content validity, utility, and meaningfulness of RA-FQ scores. RESULTS......: People with RA in observational trials in Canada (n = 896) and France (n = 138), and an RCT in the Netherlands (n = 178) completed 5 items (11-point numerical rating scale) representing RA Flare core domains. There was moderate to high evidence of reliability, content and construct validity...... to identify and measure RA flares. Its review through OMERACT Filter 2.0 shows evidence of reliability, content and construct validity, and responsiveness. These properties merit its further validation as an outcome for clinical trials....

  6. Validation of search filters for identifying pediatric studies in PubMed.

    Science.gov (United States)

    Leclercq, Edith; Leeflang, Mariska M G; van Dalen, Elvira C; Kremer, Leontien C M

    2013-03-01

    To identify and validate PubMed search filters for retrieving studies including children and to develop a new pediatric search filter for PubMed. We developed 2 different datasets of studies to evaluate the performance of the identified pediatric search filters, expressed in terms of sensitivity, precision, specificity, accuracy, and number needed to read (NNR). An optimal search filter will have a high sensitivity and high precision with a low NNR. In addition to the PubMed Limits: All Child: 0-18 years filter (in May 2012 renamed to PubMed Filter Child: 0-18 years), 6 search filters for identifying studies including children were identified: 3 developed by Kastner et al, 1 developed by BestBets, one by the Child Health Field, and 1 by the Cochrane Childhood Cancer Group. Three search filters (Cochrane Childhood Cancer Group, Child Health Field, and BestBets) had the highest sensitivity (99.3%, 99.5%, and 99.3%, respectively) but a lower precision (64.5%, 68.4%, and 66.6% respectively) compared with the other search filters. Two Kastner search filters had a high precision (93.0% and 93.7%, respectively) but a low sensitivity (58.5% and 44.8%, respectively). They failed to identify many pediatric studies in our datasets. The search terms responsible for false-positive results in the reference dataset were determined. With these data, we developed a new search filter for identifying studies with children in PubMed with an optimal sensitivity (99.5%) and precision (69.0%). Search filters to identify studies including children either have a low sensitivity or a low precision with a high NNR. A new pediatric search filter with a high sensitivity and a low NNR has been developed. Copyright © 2013 Mosby, Inc. All rights reserved.

  7. Validation of Serious Games

    Directory of Open Access Journals (Sweden)

    Katinka van der Kooij

    2015-09-01

    Full Text Available The application of games for behavioral change has seen a surge in popularity but evidence on the efficacy of these games is contradictory. Anecdotal findings seem to confirm their motivational value whereas most quantitative findings from randomized controlled trials (RCT are negative or difficult to interpret. One cause for the contradictory evidence could be that the standard RCT validation methods are not sensitive to serious games’ effects. To be able to adapt validation methods to the properties of serious games we need a framework that can connect properties of serious game design to the factors that influence the quality of quantitative research outcomes. The Persuasive Game Design model [1] is particularly suitable for this aim as it encompasses the full circle from game design to behavioral change effects on the user. We therefore use this model to connect game design features, such as the gamification method and the intended transfer effect, to factors that determine the conclusion validity of an RCT. In this paper we will apply this model to develop guidelines for setting up validation methods for serious games. This way, we offer game designers and researchers handles on how to develop tailor-made validation methods.

  8. Validation testing of radioactive waste drum filter vents

    Energy Technology Data Exchange (ETDEWEB)

    Weber, L.D. [Pall Corp., Port Washington, NY (United States); Rahimi, R.S. [Pall Corp., Cortland, NY (United States); Edling, D. [Edling & Associates, Inc., Russel Springs, KY (United States)

    1997-08-01

    The minimum requirements for Drum Filter Vents (DFVs) can be met by demonstrating conformance with the Waste Isolation Pilot Plant (WIPP) Trupact II Safety Assessment Report (SAR), and conformance with U.S. Federal shipping regulations 49 CFR 178.350, DOT Spec 7A, for Type A packages. These together address a number of safety related performance parameters such as hydrogen diffusivity, flow related pressure drop, filtration efficiency and, separately, mechanical stability and the ability to prevent liquid water in-leakage. In order to make all metal DFV technology (including metallic filter medium) available to DOE sites, Pall launched a product development program to validate an all metal design to meet these requirements. Numerous problems experienced by DOE sites in the past came to light during this development program. They led us to explore enhancements to DFV design and performance testing addressing these difficulties and concerns. The result is a patented all metal DFV certified to all applicable regulatory requirements, which for the first time solves operational and health safety problems reported by DOE site personnel but not addressed by previous DFV`s. The new technology facilitates operations (such as manual, automated and semi-automated drum handling/redrumming), sampling, on-site storage, and shipping. At the same time, it upgrades filtration efficiency in configurations documented to maintain filter efficiency following mechanical stress. 2 refs., 2 figs., 10 tabs.

  9. RCT: Module 2.07, Respiratory Protection, Course 8773

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-10

    Internal dosimetry controls require the use of engineering controls to prevent the internal deposition of radioactive and nonradiological contaminants. However, when engineering and administrative controls are not available or feasible, respiratory protection may be necessary. The radiation control technician (RCT) should know and apply the considerations used in determining the respiratory protection equipment that is most appropriate for the job. The inappropriate use of or the use of the wrong respiratory protection equipment may result in undesirable health effects. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and will provide in-the-field skills.

  10. Parametric adaptive filtering and data validation in the bar GW detector AURIGA

    CERN Document Server

    Ortolan, A; Cerdonio, M; Prodi, G A; Vedovato, G; Vitale, S

    2002-01-01

    We report on our experience gained in the signal processing of the resonant GW detector AURIGA. Signal amplitude and arrival time are estimated by means of a matched-adaptive Wiener filter. The detector noise, entering in the filter set-up, is modelled as a parametric ARMA process; to account for slow non-stationarity of the noise, the ARMA parameters are estimated on an hourly basis. A requirement of the set-up of an unbiased Wiener filter is the separation of time spans with 'almost Gaussian' noise from non-Gaussian and/or strongly non-stationary time spans. The separation algorithm consists basically of a variance estimate with the Chauvenet convergence method and a threshold on the Curtosis index. The subsequent validation of data is strictly connected with the separation procedure: in fact, by injecting a large number of artificial GW signals into the 'almost Gaussian' part of the AURIGA data stream, we have demonstrated that the effective probability distributions of the signal-to-noise ratio chi sup 2 ...

  11. The 1.3-m Robotically Controlled Telescope (RCT) at Kitt Peak - A Fifty year old dream Realized: Telescope Characteristics, Current Research and Education Progr

    Science.gov (United States)

    Guinan, Edward; Gelderman, Richard; Strolger, Louis-Gregory; Carini, Michael T.; McGruder, Charles, III; Campbell, Rachel; Walter, Donald K.; Davis, Donald R.; Tedesco, Edward F.; Engle, Scott G.

    2011-03-01

    The 1.3 m Robotically Controlled Telescope (RCT) on Kitt Peak has a rich history, including its role as a prototype for remotely controlled telescopes during the 1960s. As such, the RCT could be considered one of the first - Telescopes from Afar. The telescope, originally called the Remotely Controlled Telescope, has been renamed the Robotically Controlled Telescope to reflect the change in operational control and mode of use. The RCT was a conceptual precursor of today's robotic telescopes, but the actual operation of a remotely controlled telescope was technologically premature for its time, and was subsequently manually operated primarily to conduct optical and infrared observations as well being used as a test bed for new spectroscopic and photometric instruments. In 1995 budget constraints forced the closing of the telescope as part of the Kitt Peak National Observatory (KPNO), following nearly 30 years of distinguished service to KPNO. A request for proposals to operate this telescope was issued to the science community. The RCT consortium, lead by Western Kentucky University, was the successful proposer for operation of the telescope. After several difficult years of retrofitting, refurbishing, and automating the telecope and observatory dome, the telescope has returned to routine science operations in November 2009. The RCT has operated smoothly since that time, with no major interruptions. Observations of objects of interest to the consortium partners (including: comets & asteroids, variable & binary stars, exoplanets, supernovae, quasars & blazars) are being routinely obtained and evaluated. One of the distinguishing features of the RCT is that it is an autonomous observatory designed to handle diverse optical imaging and photometry programs. These include being able to automatically deal with a wide range of observing parameters such as -integration time, sky conditions, repetitions, return visits, filters, air mass, non-sidereal objects, transients etc

  12. Status self-validation of a multifunctional sensor using a multivariate relevance vector machine and predictive filters

    International Nuclear Information System (INIS)

    Shen, Zhengguang; Wang, Qi

    2013-01-01

    A novel strategy by using a multivariable relevance vector machine coupled with predictive filters for status self-validation of a multifunctional sensor is proposed. The working principle and online updating algorithm of predictive filters are emphasized for multiple fault detection, isolation and recovery (FDIR), and the incorrect sensor measurements are validated online. The multivariable relevance vector machine is then employed for the signal reconstruction of the multifunctional sensor to generate the final validated measurement values (VMV) of multiple measured components, in which its advantages of sparse models and multivariable simultaneous outputs are fully used. With all likely uncertainty sources of the multifunctional self-validating sensor taken into account, the uncertainty propagation model is deduced in detail to evaluate the online validated uncertainty (VU) under a fault-free situation while a qualitative uncertainty component is appended to indicate the accuracy changes of VMV under different types of fault. A real experimental system of a multifunctional self-validating sensor is designed to verify the performance of the proposed strategy. From the real-time capacity and fault recovery accuracy of FDIR, and runtime of signal reconstruction under small samples, a performance comparison among different methods is made. Results demonstrate that the proposed scheme provides a better solution to the status self-validation of a multifunctional self-validating sensor under both normal and abnormal situations. (paper)

  13. Parametric adaptive filtering and data validation in the bar GW detector AURIGA

    Science.gov (United States)

    Ortolan, A.; Baggio, L.; Cerdonio, M.; Prodi, G. A.; Vedovato, G.; Vitale, S.

    2002-04-01

    We report on our experience gained in the signal processing of the resonant GW detector AURIGA. Signal amplitude and arrival time are estimated by means of a matched-adaptive Wiener filter. The detector noise, entering in the filter set-up, is modelled as a parametric ARMA process; to account for slow non-stationarity of the noise, the ARMA parameters are estimated on an hourly basis. A requirement of the set-up of an unbiased Wiener filter is the separation of time spans with 'almost Gaussian' noise from non-Gaussian and/or strongly non-stationary time spans. The separation algorithm consists basically of a variance estimate with the Chauvenet convergence method and a threshold on the Curtosis index. The subsequent validation of data is strictly connected with the separation procedure: in fact, by injecting a large number of artificial GW signals into the 'almost Gaussian' part of the AURIGA data stream, we have demonstrated that the effective probability distributions of the signal-to-noise ratio χ2 and the time of arrival are those that are expected.

  14. Parametric adaptive filtering and data validation in the bar GW detector AURIGA

    International Nuclear Information System (INIS)

    Ortolan, A; Baggio, L; Cerdonio, M; Prodi, G A; Vedovato, G; Vitale, S

    2002-01-01

    We report on our experience gained in the signal processing of the resonant GW detector AURIGA. Signal amplitude and arrival time are estimated by means of a matched-adaptive Wiener filter. The detector noise, entering in the filter set-up, is modelled as a parametric ARMA process; to account for slow non-stationarity of the noise, the ARMA parameters are estimated on an hourly basis. A requirement of the set-up of an unbiased Wiener filter is the separation of time spans with 'almost Gaussian' noise from non-Gaussian and/or strongly non-stationary time spans. The separation algorithm consists basically of a variance estimate with the Chauvenet convergence method and a threshold on the Curtosis index. The subsequent validation of data is strictly connected with the separation procedure: in fact, by injecting a large number of artificial GW signals into the 'almost Gaussian' part of the AURIGA data stream, we have demonstrated that the effective probability distributions of the signal-to-noise ratio χ 2 and the time of arrival are those that are expected

  15. Parametric adaptive filtering and data validation in the bar GW detector AURIGA

    Energy Technology Data Exchange (ETDEWEB)

    Ortolan, A [INFN - Laboratori Nazionali di Legnaro, Via Romea, 4 I-35020 Legnaro, Padova (Italy); Baggio, L [Department of Physics, University of Trento and INFN Gruppo Collegato di Trento, I-38050 Povo, Trento (Italy); Cerdonio, M [Department of Physics, University of Padova and INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Prodi, G A [Department of Physics, University of Trento and INFN Gruppo Collegato di Trento, I-38050 Povo, Trento (Italy); Vedovato, G [INFN - Laboratori Nazionali di Legnaro, Via Romea, 4 I-35020 Legnaro, Padova (Italy); Vitale, S [Department of Physics, University of Trento and INFN Gruppo Collegato di Trento, I-38050 Povo, Trento (Italy)

    2002-04-07

    We report on our experience gained in the signal processing of the resonant GW detector AURIGA. Signal amplitude and arrival time are estimated by means of a matched-adaptive Wiener filter. The detector noise, entering in the filter set-up, is modelled as a parametric ARMA process; to account for slow non-stationarity of the noise, the ARMA parameters are estimated on an hourly basis. A requirement of the set-up of an unbiased Wiener filter is the separation of time spans with 'almost Gaussian' noise from non-Gaussian and/or strongly non-stationary time spans. The separation algorithm consists basically of a variance estimate with the Chauvenet convergence method and a threshold on the Curtosis index. The subsequent validation of data is strictly connected with the separation procedure: in fact, by injecting a large number of artificial GW signals into the 'almost Gaussian' part of the AURIGA data stream, we have demonstrated that the effective probability distributions of the signal-to-noise ratio {chi}{sup 2} and the time of arrival are those that are expected.

  16. Biotrickling filter modeling for styrene abatement. Part 1: Model development, calibration and validation on an industrial scale.

    Science.gov (United States)

    San-Valero, Pau; Dorado, Antonio D; Martínez-Soria, Vicente; Gabaldón, Carmen

    2018-01-01

    A three-phase dynamic mathematical model based on mass balances describing the main processes in biotrickling filtration: convection, mass transfer, diffusion, and biodegradation was calibrated and validated for the simulation of an industrial styrene-degrading biotrickling filter. The model considered the key features of the industrial operation of biotrickling filters: variable conditions of loading and intermittent irrigation. These features were included in the model switching from the mathematical description of periods with and without irrigation. Model equations were based on the mass balances describing the main processes in biotrickling filtration: convection, mass transfer, diffusion, and biodegradation. The model was calibrated with steady-state data from a laboratory biotrickling filter treating inlet loads at 13-74 g C m -3 h -1 and at empty bed residence time of 30-15 s. The model predicted the dynamic emission in the outlet of the biotrickling filter, simulating the small peaks of concentration occurring during irrigation. The validation of the model was performed using data from a pilot on-site biotrickling filter treating styrene installed in a fiber-reinforced facility. The model predicted the performance of the biotrickling filter working under high-oscillating emissions at an inlet load in a range of 5-23 g C m -3 h -1 and at an empty bed residence time of 31 s for more than 50 days, with a goodness of fit of 0.84. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. RCT: Module 2.04, Dosimetry, Course 8769

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-11

    This course will introduce the types of instruments used to measure external and internal radiation to people. Dosimetry is the quantitative assessment of radiation received by the human body. Several types of dosimeters are used worldwide. This information is valuable to all radiological control personnel because dosimeters are the only direct method to measure and document personnel radiation exposure and ensure regulatory compliance with applicable limits. This course will cover dosimetry terms, Department of Energy (DOE) limits, Los Alamos National Laboratory (LANL) administrative guidelines, thermoluminescent dosimeters (TLDs), LANL dosimetry, and bioassay assessment methods. This course will prepare the student with the skills necessary for radiological control technician (RCT) qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and providing in-thefield skills.

  18. Manufacturing facilities of pharmaceutical products and measures for purification of its environment. Validation for sterilizing grade filter; Iyakuhin no seizo shisetsu to kankyo seijoka taisaku. Mekkin`yo firuta no barideshon

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, M.

    1994-07-31

    Validation is defined as firm establishment of a documentary evidence showing the system concerned is functioning as designed. Validation for sterilizing grade filter is not limited only to validation of the filter itself, but evaluation of its extract as well as adsorption and the sterilizing condition of the filter and system are the items to be examined. It is necessary to make validation of the filtering system as a whole taking into consideration any kind of element of composition in order to reach the target. In this article, in order to avoid description on diversified subjects, only validation for the filter is focused and its technique is introduced. The procedure for executing validation is stated first, and concerning validation for the sterilizing grade filter, a bacterial retention test is explained in detail, then with regard to an integrity test, sterilization of the devise concerned and pharmaceutical suitability/extract tests, the points which call special attention and testing items are introduced. Finally self inspection and evaluation of operating performance qualification are described. 13 refs., 7 figs., 2 tabs.

  19. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Tugwell, Peter; Boers, Maarten; D'Agostino, Maria-Antonietta

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter requires that criteria be met to demonstrate that the outcome instrument meets...... the criteria for content, face, and construct validity. METHODS: Discussion groups critically reviewed a variety of ways in which case studies of current OMERACT Working Groups complied with the Truth component of the Filter and what issues remained to be resolved. RESULTS: The case studies showed...... that there is broad agreement on criteria for meeting the Truth criteria through demonstration of content, face, and construct validity; however, several issues were identified that the Filter Working Group will need to address. CONCLUSION: These issues will require resolution to reach consensus on how Truth...

  20. Benefits and Disadvantages of Neoadjuvant Radiochemotherapy (RCT) in the Multimodal Therapy of Squamous Esophageal Cancer (ESC).

    Science.gov (United States)

    Hanna, Adrian; Birla, Rodica; Iosif, Cristina; Boeriu, Marius; Constantinoiu, Silviu

    2016-01-01

    The purpose of this paper is to present the advantages and disadvantages of neoadjuvant RCT in multimodal therapyof ESC. Between 1998-2014 221 patients were treated with ESC, 85 of whom received neoadjuvant RCT. For these we have made imaging and pathologic assessment of response using RECIST and MANDARD criteria and statistical data were interpreted in terms of the factors that influence the response. Also, they were evaluated statistical correlations between RCT and resectability, postoperative morbidity, mortality and long-term survival. 45 patients were imagistic responders and 34 underwent surgery, 40 non-responders of which 14 underwent surgery. Of the 48 surgical patients with preoperative RCT, histopathological evaluation showed that 32 were pathological responders and 16 non responders. There were performed statistical analyzes of correlations between RCT and resectability, stage, location of ESC, morbidity, mortality and survival. RCT increase resectability, improves survival and maximum duration of survival, more in responders than in nonresponders and does not affect postoperative complications and postoperative mortality, nor among the responders or nonresponders. Imaging evaluation result of the response to RCT overestimate responders. Celsius.

  1. Software Verification and Validation Test Report for the HEPA filter Differential Pressure Fan Interlock System

    International Nuclear Information System (INIS)

    ERMI, A.M.

    2000-01-01

    The HEPA Filter Differential Pressure Fan Interlock System PLC ladder logic software was tested using a Software Verification and Validation (VandV) Test Plan as required by the ''Computer Software Quality Assurance Requirements''. The purpose of his document is to report on the results of the software qualification

  2. RCT: Module 2.11, Radiological Work Coverage, Course 8777

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-20

    Radiological work is usually approved and controlled by radiation protection personnel by using administrative and procedural controls, such as radiological work permits (RWPs). In addition, some jobs will require working in, or will have the potential for creating, very high radiation, contamination, or airborne radioactivity areas. Radiological control technicians (RCTs) providing job coverage have an integral role in controlling radiological hazards. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and will provide in-the-field skills.

  3. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    D'Agostino, Maria-Antonietta; Boers, Maarten; Kirwan, John

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imaging...... using the original OMERACT Filter and the newly proposed structure. Breakout groups critically reviewed the extent to which the candidate biomarkers complied with the proposed stepwise approach, as a way of examining the utility of the proposed 3-dimensional structure. RESULTS: Although...... was obtained for a proposed tri-axis structure to assess validation of imaging and soluble biomarkers; nevertheless, additional work is required to better evaluate its place within the OMERACT Filter 2.0....

  4. Assessing the performance of methodological search filters to improve the efficiency of evidence information retrieval: five literature reviews and a qualitative study.

    Science.gov (United States)

    Lefebvre, Carol; Glanville, Julie; Beale, Sophie; Boachie, Charles; Duffy, Steven; Fraser, Cynthia; Harbour, Jenny; McCool, Rachael; Smith, Lynne

    2017-11-01

    Effective study identification is essential for conducting health research, developing clinical guidance and health policy and supporting health-care decision-making. Methodological search filters (combinations of search terms to capture a specific study design) can assist in searching to achieve this. This project investigated the methods used to assess the performance of methodological search filters, the information that searchers require when choosing search filters and how that information could be better provided. Five literature reviews were undertaken in 2010/11: search filter development and testing; comparison of search filters; decision-making in choosing search filters; diagnostic test accuracy (DTA) study methods; and decision-making in choosing diagnostic tests. We conducted interviews and a questionnaire with experienced searchers to learn what information assists in the choice of search filters and how filters are used. These investigations informed the development of various approaches to gathering and reporting search filter performance data. We acknowledge that there has been a regrettable delay between carrying out the project, including the searches, and the publication of this report, because of serious illness of the principal investigator. The development of filters most frequently involved using a reference standard derived from hand-searching journals. Most filters were validated internally only. Reporting of methods was generally poor. Sensitivity, precision and specificity were the most commonly reported performance measures and were presented in tables. Aspects of DTA study methods are applicable to search filters, particularly in the development of the reference standard. There is limited evidence on how clinicians choose between diagnostic tests. No published literature was found on how searchers select filters. Interviewing and questioning searchers via a questionnaire found that filters were not appropriate for all tasks but were

  5. Method validation using weighted linear regression models for quantification of UV filters in water samples.

    Science.gov (United States)

    da Silva, Claudia Pereira; Emídio, Elissandro Soares; de Marchi, Mary Rosa Rodrigues

    2015-01-01

    This paper describes the validation of a method consisting of solid-phase extraction followed by gas chromatography-tandem mass spectrometry for the analysis of the ultraviolet (UV) filters benzophenone-3, ethylhexyl salicylate, ethylhexyl methoxycinnamate and octocrylene. The method validation criteria included evaluation of selectivity, analytical curve, trueness, precision, limits of detection and limits of quantification. The non-weighted linear regression model has traditionally been used for calibration, but it is not necessarily the optimal model in all cases. Because the assumption of homoscedasticity was not met for the analytical data in this work, a weighted least squares linear regression was used for the calibration method. The evaluated analytical parameters were satisfactory for the analytes and showed recoveries at four fortification levels between 62% and 107%, with relative standard deviations less than 14%. The detection limits ranged from 7.6 to 24.1 ng L(-1). The proposed method was used to determine the amount of UV filters in water samples from water treatment plants in Araraquara and Jau in São Paulo, Brazil. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Identification of the rctA Gene, Which Is Required for Repression of Conjugative Transfer of Rhizobial Symbiotic Megaplasmids†

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Sepúlveda, Edgardo; Pando, Victoria; Muñoz, Socorro; Nogales, Joaquina; Olivares, José; Soto, Maria J.; Herrera-Cervera, José A.; Romero, David; Brom, Susana; Sanjuán, Juan

    2005-01-01

    An analysis of the conjugative transfer of pRetCFN42d, the symbiotic plasmid (pSym) of Rhizobium etli, has revealed a novel gene, rctA, as an essential element of a regulatory system for silencing the conjugative transfer of R. etli pSym by repressing the transcription of conjugal transfer genes in standard laboratory media. The rctA gene product lacks sequence conservation with other proteins of known function but may belong to the winged-helix DNA-binding subfamily of transcriptional regulators. Similar to that of many transcriptional repressors, rctA transcription seems to be positively autoregulated. rctA expression is greatly reduced upon overexpression of another gene, rctB, previously identified as a putative activator of R. etli pSym conjugal transfer. Thus, rctB seems to counteract the repressive action of rctA. rctA homologs are present in at least three other bacterial genomes within the order Rhizobiales, where they are invariably located adjacent to and divergently transcribed from putative virB-like operons. We show that similar to that of R. etli pSym, conjugative transfer of the 1.35-Mb symbiotic megaplasmid A of Sinorhizobium meliloti is also subjected to the inhibitory action of rctA. Our data provide strong evidence that the R. etli and S. meliloti pSym plasmids are indeed self-conjugative plasmids and that this property would only be expressed under optimal, as yet unknown conditions that entail inactivation of the rctA function. The rctA gene seems to represent novel but probably widespread regulatory systems controlling the transfer of conjugative elements within the order Rhizobiales. PMID:16237017

  7. RCT: Module 2.08, Radiological Source Control, Course 8774

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-10

    radioactive source is material used for its emitted radiation. Sources are sealed or unsealed and are classified as accountable or exempt. Radioactive sources are used for response checks, functional checks, and the calibration of instruments and monitors to traceable standards. To ensure the safety and welfare of all personnel, it is important to maintain control of radioactive sources to minimize the potential for the spread of contamination, unnecessary exposure to personnel, loss or theft, and improper disposal. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and will provide in-the-field skills.

  8. RCT: 2.02 Communication Systems, Course #33339

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-01

    This unit will present an overview of communication systems at LANL. Good communication skills are essential to an RCT. RCTs should develop an ability to communicate, using both verbal and nonverbal media. These skills will ensure that important information is transmitted to the proper individuals in a clear and concise manner.

  9. RCT: Module 2.10, Access Control and Work Area Setup, Course 8776

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-11

    This course presents information on radiological work permits (RWPs), various types of postings used in radiological areas, radiological area setups, access controls, and releases of material from radiological areas. All of these are fundamental duties of RCTs. This course will prepare the student with the skills necessary for radiological control technician (RCT) qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and providing in-thefield skills.

  10. RCT: Module 2.06, Air Sampling Program and Methods, Course 8772

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-19

    The inhalation of radioactive particles is the largest cause of an internal radiation dose. Airborne radioactivity measurements are necessary to ensure that the control measures are and continue to be effective. Regulations govern the allowable effective dose equivalent to an individual. The effective dose equivalent is determined by combining the external and internal dose equivalent values. Typically, airborne radioactivity levels are maintained well below allowable levels to keep the total effective dose equivalent small. This course will prepare the student with the skills necessary for RCT qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and will provide in-the-field skills.

  11. Bicycle Trains, Cycling, and Physical Activity: A Pilot Cluster RCT.

    Science.gov (United States)

    Mendoza, Jason A; Haaland, Wren; Jacobs, Maya; Abbey-Lambertz, Mark; Miller, Josh; Salls, Deb; Todd, Winifred; Madding, Rachel; Ellis, Katherine; Kerr, Jacqueline

    2017-10-01

    Increasing children's cycling to school and physical activity are national health goals. The objective was to conduct an RCT of a bicycle train program to assess impact on students' school travel mode and moderate-to-vigorous physical activity (MVPA). Pilot cluster RCT with randomization at the school level and N=54 participants. Fourth-fifth graders from four public schools serving low-income families in Seattle, WA in 2014 with analyses in 2015-2016. All participants were provided and fitted with bicycles, safety equipment (helmets, locks, and lights), and a 2- to 3-hour bicycle safety course. The intervention was a bicycle train offered daily (i.e., students volunteered to cycle with study staff to and from school). Time 1 assessments occurred prior to randomization. Time 2 assessments occurred after 3-5 weeks of the intervention (i.e., during Weeks 4-6 of the intervention period). The primary outcome was the percentage of daily commutes to school by cycling measured by validated survey. MVPA, measured by accelerometry and GPS units and processed by machine learning algorithms, was a secondary outcome. For two separate adjusted repeated measures linear mixed effects models in which students (N=54) were nested within schools (N=4), intervention participants had: (1) an absolute increase in mean percentage of daily commutes by cycling of 44.9%, (95% CI=26.8, 63.0) and (2) an increase in mean MVPA of 21.6 minutes/day, (95% CI=8.7, 34.6) from Time 1 to Time 2 compared with controls. A pilot bicycle train intervention increased cycling to school and daily MVPA in the short term among diverse, inner-city elementary school students. The bicycle train intervention appears promising and warrants further experimental trials among large, diverse samples with longer follow-up. This study is registered at www.clinicaltrials.gov NCT02006186. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  12. RCT: Module 2.03, Counting Errors and Statistics, Course 8768

    Energy Technology Data Exchange (ETDEWEB)

    Hillmer, Kurt T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-04-01

    Radiological sample analysis involves the observation of a random process that may or may not occur and an estimation of the amount of radioactive material present based on that observation. Across the country, radiological control personnel are using the activity measurements to make decisions that may affect the health and safety of workers at those facilities and their surrounding environments. This course will present an overview of measurement processes, a statistical evaluation of both measurements and equipment performance, and some actions to take to minimize the sources of error in count room operations. This course will prepare the student with the skills necessary for radiological control technician (RCT) qualification by passing quizzes, tests, and the RCT Comprehensive Phase 1, Unit 2 Examination (TEST 27566) and by providing in the field skills.

  13. Concrete ensemble Kalman filters with rigorous catastrophic filter divergence.

    Science.gov (United States)

    Kelly, David; Majda, Andrew J; Tong, Xin T

    2015-08-25

    The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature.

  14. The RCT 1.3 m robotic telescope: broadband color transformation and extinction calibration

    Energy Technology Data Exchange (ETDEWEB)

    Strolger, L.-G.; Gott, A. M.; Carini, M.; Gelderman, R.; Laney, C. D.; McGruder, C. [Western Kentucky University, Bowling Green, KY 42101 (United States); Engle, S.; Guinan, E. [Villanova University, Villanova, PA 19085 (United States); Treffers, R. R. [Starman Systems, LLC, Alamo, CA 94507 (United States); Walter, D. K., E-mail: strolger@stsci.edu [South Carolina State University, Orangeburg, SC 29117 (United States)

    2014-03-01

    The Robotically Controlled Telescope (RCT) 1.3 m telescope, formerly known as the Kitt Peak National Observatory (KPNO) 50 inch telescope, has been refurbished as a fully robotic telescope, with an autonomous scheduler to take full advantage of the observing site without the requirement of a human presence. Here we detail the current configuration of the RCT and present, as a demonstration of its high-priority science goals, the broadband UBVRI photometric calibration of the optical facility. In summary, we find the linear color transformation and extinction corrections to be consistent with similar optical KPNO facilities, to within a photometric precision of 10% (at 1σ). While there were identified instrumental errors that likely added to the overall uncertainty, associated with since-resolved issues in engineering and maintenance of the robotic facility, a preliminary verification of this calibration gave a good indication that the solution is robust, perhaps to a higher precision than this initial calibration implies. The RCT has been executing regular science operations since 2009 and is largely meeting the science requirements set during its acquisition and redesign.

  15. DSP Control of Line Hybrid Active Filter

    DEFF Research Database (Denmark)

    Dan, Stan George; Benjamin, Doniga Daniel; Magureanu, R.

    2005-01-01

    Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter...... is studied for current harmonic compensation. The hybrid filter is formed by a single tuned Le filter and a small-rated power active filter, which are directly connected in series without any matching transformer. Thus the required rating of the active filter is much smaller than a conventional standalone...... active filter. Simulation and experimental results obtained in laboratory confirmed the validity and effectiveness of the control....

  16. Optimal search filters for renal information in EMBASE.

    Science.gov (United States)

    Iansavichus, Arthur V; Haynes, R Brian; Shariff, Salimah Z; Weir, Matthew; Wilczynski, Nancy L; McKibbon, Ann; Rehman, Faisal; Garg, Amit X

    2010-07-01

    EMBASE is a popular database used to retrieve biomedical information. Our objective was to develop and test search filters to help clinicians and researchers efficiently retrieve articles with renal information in EMBASE. We used a diagnostic test assessment framework because filters operate similarly to screening tests. We divided a sample of 5,302 articles from 39 journals into development and validation sets of articles. Information retrieval properties were assessed by treating each search filter as a "diagnostic test" or screening procedure for the detection of relevant articles. We tested the performance of 1,936,799 search filters made of unique renal terms and their combinations. REFERENCE STANDARD & OUTCOME: The reference standard was manual review of each article. We calculated the sensitivity and specificity of each filter to identify articles with renal information. The best renal filters consisted of multiple search terms, such as "renal replacement therapy," "renal," "kidney disease," and "proteinuria," and the truncated terms "kidney," "dialy," "neph," "glomerul," and "hemodial." These filters achieved peak sensitivities of 98.7% (95% CI, 97.9-99.6) and specificities of 98.5% (95% CI, 98.0-99.0). The retrieval performance of these filters remained excellent in the validation set of independent articles. The retrieval performance of any search will vary depending on the quality of all search concepts used, not just renal terms. We empirically developed and validated high-performance renal search filters for EMBASE. These filters can be programmed into the search engine or used on their own to improve the efficiency of searching.

  17. Experimental validation of a method characterizing bow tie filters in CT scanners using a real-time dose probe

    International Nuclear Information System (INIS)

    McKenney, Sarah E.; Nosratieh, Anita; Gelskey, Dale; Yang Kai; Huang Shinying; Chen Lin; Boone, John M.

    2011-01-01

    Purpose: Beam-shaping or ''bow tie'' (BT) filters are used to spatially modulate the x-ray beam in a CT scanner, but the conventional method of step-and-shoot measurement to characterize a beam's profile is tedious and time-consuming. The theory for characterization of bow tie relative attenuation (COBRA) method, which relies on a real-time dosimeter to address the issues of conventional measurement techniques, was previously demonstrated using computer simulations. In this study, the feasibility of the COBRA theory is further validated experimentally through the employment of a prototype real-time radiation meter and a known BT filter. Methods: The COBRA method consisted of four basic steps: (1) The probe was placed at the edge of a scanner's field of view; (2) a real-time signal train was collected as the scanner's gantry rotated with the x-ray beam on; (3) the signal train, without a BT filter, was modeled using peak values measured in the signal train of step 2; and (4) the relative attenuation of the BT filter was estimated from filtered and unfiltered data sets. The prototype probe was first verified to have an isotropic and linear response to incident x-rays. The COBRA method was then tested on a dedicated breast CT scanner with a custom-designed BT filter and compared to the conventional step-and-shoot characterization of the BT filter. Using basis decomposition of dual energy signal data, the thickness of the filter was estimated and compared to the BT filter's manufacturing specifications. The COBRA method was also demonstrated with a clinical whole body CT scanner using the body BT filter. The relative attenuation was calculated at four discrete x-ray tube potentials and used to estimate the thickness of the BT filter. Results: The prototype probe was found to have a linear and isotropic response to x-rays. The relative attenuation produced from the COBRA method fell within the error of the relative attenuation measured with the step-and-shoot method

  18. Some arithmetically symmetrical bandpass filters

    Science.gov (United States)

    Paranasi, P.; Roy, S. C. D.

    1981-01-01

    A combination of the conventional and Matthaei lowpass-bandpass transformations is shown to result in some bandpass filters having very good arithmetic symmetry. The technique presented is applicable to the Butterworth and inverse Chebyshev types of magnitude approximations and the Bessel type of delay approximations. It is not valid, however, for the Chebyshev and elliptic varieties of filters.

  19. Theory and validation of a liquid radiation filter greenhouse simulation for performance prediction

    International Nuclear Information System (INIS)

    Feuermann, D.; Kopel, R.; Zeroni, M.; Levi, S.; Gale, J.

    1997-01-01

    A greenhouse is described which has a selectively absorbing liquid radiation filter (LRF) circulating in double layered cladding. The filter removes much of the near infrared wave band of solar radiation (700 nm) while transmitting most of the photosynthetic radiation (400-700 nm). This greatly reduces the heat input to the greenhouse and, by transferring heat from day to night, facilitates better temperature control. This is particularly important for CO2 fertilization, which requires that the greenhouse should remain closed during daylight hours. A computer simulation model was developed to study the relationship between design parameters of such a LRF greenhouse and its thermal performance under different climatic conditions. The model was based on a small number of governing equations describing the major physical phenomena responsible for the greenhouse climate. Validation of the simulation was performed with data from a 330 m2 LRF greenhouse, operating in the Negev (Israel) desert highlands. The predicted greenhouse temperatures were found to agree with measured values to within one to two degrees Celsius. Performances of a LRF and a conventional greenhouse were compared using the simulation and hourly meteorological data for central Israel. For the summer season of May to October, the number of daylight hours during which the LRF greenhouse could remain closed was larger by about two-thirds than that of the conventional greenhouse

  20. Filtered-X Affine Projection Algorithms for Active Noise Control Using Volterra Filters

    Directory of Open Access Journals (Sweden)

    Sicuranza Giovanni L

    2004-01-01

    Full Text Available We consider the use of adaptive Volterra filters, implemented in the form of multichannel filter banks, as nonlinear active noise controllers. In particular, we discuss the derivation of filtered-X affine projection algorithms for homogeneous quadratic filters. According to the multichannel approach, it is then easy to pass from these algorithms to those of a generic Volterra filter. It is shown in the paper that the AP technique offers better convergence and tracking capabilities than the classical LMS and NLMS algorithms usually applied in nonlinear active noise controllers, with a limited complexity increase. This paper extends in two ways the content of a previous contribution published in Proc. IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03, Grado, Italy, June 2003. First of all, a general adaptation algorithm valid for any order of affine projections is presented. Secondly, a more complete set of experiments is reported. In particular, the effects of using multichannel filter banks with a reduced number of channels are investigated and relevant results are shown.

  1. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Kirwan, John R; Boers, Maarten; Hewlett, Sarah

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes...... for defining core areas of measurement ("Filter 2.0 Core Areas of Measurement") was presented at OMERACT 11 to explore areas of consensus and to consider whether already endorsed core outcome sets fit into this newly proposed framework. METHODS: Discussion groups critically reviewed the extent to which case......, presentation, and clarity of the framework were questioned. The discussion groups and subsequent feedback highlighted 20 such issues. CONCLUSION: These issues will require resolution to reach consensus on accepting the proposed Filter 2.0 framework of Core Areas as the basis for the selection of Core Outcome...

  2. Performance and optimisation of trickling filters on eel farms

    NARCIS (Netherlands)

    Kamstra, A.; Heul, van der J.W.; Nijhof, M.

    1998-01-01

    The design of trickling filters used on commercial eel farms differs considerably with respect to dimensions, hydraulic and substrate loads and filter medium applied. In this paper, a model, developed for ammonium removal in a pilot-scale trickling filter, has been validated for a range of

  3. Signal Enhancement with Variable Span Linear Filters

    DEFF Research Database (Denmark)

    Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

    . Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal...... the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of these filters are analyzed in terms of their noise reduction capabilities and desired signal distortion, and the analyses are validated and further explored in simulations....

  4. Two-stage nonrecursive filter/decimator

    International Nuclear Information System (INIS)

    Yoder, J.R.; Richard, B.D.

    1980-08-01

    A two-stage digital filter/decimator has been designed and implemented to reduce the sampling rate associated with the long-term computer storage of certain digital waveforms. This report describes the design selection and implementation process and serves as documentation for the system actually installed. A filter design with finite-impulse response (nonrecursive) was chosen for implementation via direct convolution. A newly-developed system-test statistic validates the system under different computer-operating environments

  5. Passive target tracking using marginalized particle filter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A marginalized particle filtering(MPF)approach is proposed for target tracking under the background of passive measurement.Essentially,the MPF is a combination of particle filtering technique and Kalman filter.By making full use of marginalization,the distributions of the tractable linear part of the total state variables are updated analytically using Kalman filter,and only the lower-dimensional nonlinear state variable needs to be dealt with using particle filter.Simulation studies are performed on an illustrative example,and the results show that the MPF method leads to a significant reduction of the tracking errors when compared with the direct particle implementation.Real data test results also validate the effectiveness of the presented method.

  6. The three stages of building and testing mid-level theories in a realist RCT: a theoretical and methodological case-example.

    Science.gov (United States)

    Jamal, Farah; Fletcher, Adam; Shackleton, Nichola; Elbourne, Diana; Viner, Russell; Bonell, Chris

    2015-10-15

    Randomised controlled trials (RCTs) of social interventions are often criticised as failing to open the 'black box' whereby they only address questions about 'what works' without explaining the underlying processes of implementation and mechanisms of action, and how these vary by contextual characteristics of person and place. Realist RCTs are proposed as an approach to evaluation science that addresses these gaps while preserving the strengths of RCTs in providing evidence with strong internal validity in estimating effects. In the context of growing interest in designing and conducting realist trials, there is an urgent need to offer a worked example to provide guidance on how such an approach might be practically taken forward. The aim of this paper is to outline a three-staged theoretical and methodological process of undertaking a realist RCT using the example of the evaluation of a whole-school restorative intervention aiming to reduce aggression and bullying in English secondary schools. First, informed by the findings of our initial pilot trial and sociological theory, we elaborate our theory of change and specific a priori hypotheses about how intervention mechanisms interact with context to produce outcomes. Second, we describe how we will use emerging findings from the integral process evaluation within the RCT to refine, and add to, these a priori hypotheses before the collection of quantitative, follow-up data. Third, we will test our hypotheses using a combination of process and outcome data via quantitative analyses of effect mediation (examining mechanisms) and moderation (examining contextual contingencies). The results are then used to refine and further develop the theory of change. The aim of the realist RCT approach is thus not merely to assess whether the intervention is effective or not, but to develop empirically informed mid-range theory through a three-stage process. There are important implications for those involved with reporting and

  7. Mixing Methods in Randomized Controlled Trials (RCTs): Validation, Contextualization, Triangulation, and Control

    Science.gov (United States)

    Spillane, James P.; Pareja, Amber Stitziel; Dorner, Lisa; Barnes, Carol; May, Henry; Huff, Jason; Camburn, Eric

    2010-01-01

    In this paper we described how we mixed research approaches in a Randomized Control Trial (RCT) of a school principal professional development program. Using examples from our study we illustrate how combining qualitative and quantitative data can address some key challenges from validating instruments and measures of mediator variables to…

  8. Kalman Filter for Generalized 2-D Roesser Models

    Institute of Scientific and Technical Information of China (English)

    SHENG Mei; ZOU Yun

    2007-01-01

    The design problem of the state filter for the generalized stochastic 2-D Roesser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The wellknown Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of "scanning line by line", the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.

  9. Alexander fractional differential window filter for ECG denoising.

    Science.gov (United States)

    Verma, Atul Kumar; Saini, Indu; Saini, Barjinder Singh

    2018-06-01

    The electrocardiogram (ECG) non-invasively monitors the electrical activities of the heart. During the process of recording and transmission, ECG signals are often corrupted by various types of noises. Minimizations of these noises facilitate accurate detection of various anomalies. In the present paper, Alexander fractional differential window (AFDW) filter is proposed for ECG signal denoising. The designed filter is based on the concept of generalized Alexander polynomial and the R-L differential equation of fractional calculus. This concept is utilized to formulate a window that acts as a forward filter. Thereafter, the backward filter is constructed by reversing the coefficients of the forward filter. The proposed AFDW filter is then obtained by averaging of the forward and backward filter coefficients. The performance of the designed AFDW filter is validated by adding the various type of noise to the original ECG signal obtained from MIT-BIH arrhythmia database. The two non-diagnostic measure, i.e., SNR, MSE, and one diagnostic measure, i.e., wavelet energy based diagnostic distortion (WEDD) have been employed for the quantitative evaluation of the designed filter. Extensive experimentations on all the 48-records of MIT-BIH arrhythmia database resulted in average SNR of 22.014 ± 3.806365, 14.703 ± 3.790275, 13.3183 ± 3.748230; average MSE of 0.001458 ± 0.00028, 0.0078 ± 0.000319, 0.01061 ± 0.000472; and average WEDD value of 0.020169 ± 0.01306, 0.1207 ± 0.061272, 0.1432 ± 0.073588, for ECG signal contaminated by the power line, random, and the white Gaussian noise respectively. A new metric named as morphological power preservation measure (MPPM) is also proposed that account for the power preservance (as indicated by PSD plots) and the QRS morphology. The proposed AFDW filter retained much of the original (clean) signal power without any significant morphological distortion as validated by MPPM measure that were 0

  10. Validation of HPLC method for the simultaneous and quantitative determination of 12 UV-filters in cosmetics.

    Science.gov (United States)

    Nyeborg, M; Pissavini, M; Lemasson, Y; Doucet, O

    2010-02-01

    The aim of the study was the validation of a high-performance liquid chromatography (HPLC) method for the simultaneous and quantitative determination of twelve commonly used organic UV-filters (phenylbenzimidazole sulfonic acid, benzophenone-3, isoamyl p-methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, octocrylene, ethylhexyl methoxycinnamate, ethylhexyl salicylate, butyl methoxydibenzoylmethane, diethylhexyl butamido triazone, ethylhexyl triazone, methylene bis-benzotriazolyl tetramethylbutylphenol and bis-ethylhexyloxyphenol methoxyphenyl triazine) contained in suncare products. The separation and quantitative determination was performed in <30 min, using a Symmetry Shield(R) C18 (5 microm) column from Waters and a mobile phase (gradient mode) consisting of ethanol and acidified water. UV measurements were carried out at multi-wavelengths, according to the absorption of the analytes.

  11. Proposing Wavelet-Based Low-Pass Filter and Input Filter to Improve Transient Response of Grid-Connected Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Bijan Rahmani

    2016-08-01

    Full Text Available Available photovoltaic (PV systems show a prolonged transient response, when integrated into the power grid via active filters. On one hand, the conventional low-pass filter, employed within the integrated PV system, works with a large delay, particularly in the presence of system’s low-order harmonics. On the other hand, the switching of the DC (direct current–DC converters within PV units also prolongs the transient response of an integrated system, injecting harmonics and distortion through the PV-end current. This paper initially develops a wavelet-based low-pass filter to improve the transient response of the interconnected PV systems to grid lines. Further, a damped input filter is proposed within the PV system to address the raised converter’s switching issue. Finally, Matlab/Simulink simulations validate the effectiveness of the proposed wavelet-based low-pass filter and damped input filter within an integrated PV system.

  12. Switching non-local median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2015-06-01

    This paper describes a novel image filtering method for removal of random-valued impulse noise superimposed on grayscale images. Generally, it is well known that switching-type median filters are effective for impulse noise removal. In this paper, we propose a more sophisticated switching-type impulse noise removal method in terms of detail-preserving performance. Specifically, the noise detector of the proposed method finds out noise-corrupted pixels by focusing attention on the difference between the value of a pixel of interest (POI) and the median of its neighboring pixel values, and on the POI's isolation tendency from the surrounding pixels. Furthermore, the removal of the detected noise is performed by the newly proposed median filter based on non-local processing, which has superior detail-preservation capability compared to the conventional median filter. The effectiveness and the validity of the proposed method are verified by some experiments using natural grayscale images.

  13. Photonic filtering of microwave signals in the frequency range of 0.01-20 GHz using a Fabry-Perot filter

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo-Rodriguez, G; Zaldivar-Huerta, I E [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE). Sta. Maria Tonantzintla, Pue. Mexico (Mexico); GarcIa-Juarez, A [Depto. de Investigacion en Fisica, Universidad de Sonora (UNISON) Hermosillo, Son. Mexico (Mexico); Rodriguez-Asomoza, J [Depto. de Ingenieria Electronica, Universidad de las Americas-Puebla (UDLA). San Andres Cholula, Pue. Mexico (Mexico); Larger, L; Courjal, N [Laboratoire d' Optique P. M. Duffieux, UMR 6603 CNRS, Institut des Microtechiques de Franche-Comte, FRW 0067, UFR Sciences et Techniques, Universite de Franche-Comte (UFC), Besancon cedex (France)

    2011-01-01

    We demonstrate experimentally the efficiency of tuning of a photonic filter in the frequency range of 0.01 to 20 GHz. The presented work combines the use of a multimode optical source associated with a dispersive optical fiber to obtain the filtering effect. Tunability effect is achieved by the use of a Fabry-Perot filter that allows altering the spectral characteristics of the optical source. Experimental results are validated by means of numerical simulations. The scheme here proposed has a potential application in the field of optical telecommunications.

  14. Voltage harmonic elimination with RLC based interface smoothing filter

    International Nuclear Information System (INIS)

    Chandrasekaran, K; Ramachandaramurthy, V K

    2015-01-01

    A method is proposed for designing a Dynamic Voltage Restorer (DVR) with RLC interface smoothing filter. The RLC filter connected between the IGBT based Voltage Source Inverter (VSI) is attempted to eliminate voltage harmonics in the busbar voltage and switching harmonics from VSI by producing a PWM controlled harmonic voltage. In this method, the DVR or series active filter produces PWM voltage that cancels the existing harmonic voltage due to any harmonic voltage source. The proposed method is valid for any distorted busbar voltage. The operating VSI handles no active power but only harmonic power. The DVR is able to suppress the lower order switching harmonics generated by the IGBT based VSI. Good dynamic and transient results obtained. The Total Harmonic Distortion (THD) is minimized to zero at the sensitive load end. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of RLC filter. Simulated results are presented. (paper)

  15. Blind Source Parameters for Performance Evaluation of Despeckling Filters

    Directory of Open Access Journals (Sweden)

    Nagashettappa Biradar

    2016-01-01

    Full Text Available The speckle noise is inherent to transthoracic echocardiographic images. A standard noise-free reference echocardiographic image does not exist. The evaluation of filters based on the traditional parameters such as peak signal-to-noise ratio, mean square error, and structural similarity index may not reflect the true filter performance on echocardiographic images. Therefore, the performance of despeckling can be evaluated using blind assessment metrics like the speckle suppression index, speckle suppression and mean preservation index (SMPI, and beta metric. The need for noise-free reference image is overcome using these three parameters. This paper presents a comprehensive analysis and evaluation of eleven types of despeckling filters for echocardiographic images in terms of blind and traditional performance parameters along with clinical validation. The noise is effectively suppressed using the logarithmic neighborhood shrinkage (NeighShrink embedded with Stein’s unbiased risk estimation (SURE. The SMPI is three times more effective compared to the wavelet based generalized likelihood estimation approach. The quantitative evaluation and clinical validation reveal that the filters such as the nonlocal mean, posterior sampling based Bayesian estimation, hybrid median, and probabilistic patch based filters are acceptable whereas median, anisotropic diffusion, fuzzy, and Ripplet nonlinear approximation filters have limited applications for echocardiographic images.

  16. Blind Source Parameters for Performance Evaluation of Despeckling Filters.

    Science.gov (United States)

    Biradar, Nagashettappa; Dewal, M L; Rohit, ManojKumar; Gowre, Sanjaykumar; Gundge, Yogesh

    2016-01-01

    The speckle noise is inherent to transthoracic echocardiographic images. A standard noise-free reference echocardiographic image does not exist. The evaluation of filters based on the traditional parameters such as peak signal-to-noise ratio, mean square error, and structural similarity index may not reflect the true filter performance on echocardiographic images. Therefore, the performance of despeckling can be evaluated using blind assessment metrics like the speckle suppression index, speckle suppression and mean preservation index (SMPI), and beta metric. The need for noise-free reference image is overcome using these three parameters. This paper presents a comprehensive analysis and evaluation of eleven types of despeckling filters for echocardiographic images in terms of blind and traditional performance parameters along with clinical validation. The noise is effectively suppressed using the logarithmic neighborhood shrinkage (NeighShrink) embedded with Stein's unbiased risk estimation (SURE). The SMPI is three times more effective compared to the wavelet based generalized likelihood estimation approach. The quantitative evaluation and clinical validation reveal that the filters such as the nonlocal mean, posterior sampling based Bayesian estimation, hybrid median, and probabilistic patch based filters are acceptable whereas median, anisotropic diffusion, fuzzy, and Ripplet nonlinear approximation filters have limited applications for echocardiographic images.

  17. Kalman Filtering for Delayed Singular Systems with Multiplicative Noise

    Institute of Scientific and Technical Information of China (English)

    Xiao Lu; Linglong Wang; Haixia Wang; Xianghua Wang

    2016-01-01

    Kalman filtering problem for singular systems is dealt with,where the measurements consist of instantaneous measurements and delayed ones,and the plant includes multiplicative noise.By utilizing standard singular value decomposition,the restricted equivalent delayed system is presented,and the Kalman filters for the restricted equivalent system are given by using the well-known re-organization of innovation analysis lemma.The optimal Kalman filter for the original system is given based on the above Kalman filter by recursive Riccati equations,and a numerical example is presented to show the validity and efficiency of the proposed approach,where the comparison between the filter and predictor is also given.

  18. Kalman Filtering for Delayed Singular Systems with Multiplicative Noise

    Institute of Scientific and Technical Information of China (English)

    Xiao Lu; Linglong Wang; Haixia Wang; Xianghua Wang

    2016-01-01

    Kalman filtering problem for singular systems is dealt with, where the measurements consist of instantaneous measurements and delayed ones, and the plant includes multiplicative noise. By utilizing standard singular value decomposition, the restricted equivalent delayed system is presented, and the Kalman filters for the restricted equivalent system are given by using the well-known re-organization of innovation analysis lemma. The optimal Kalman filter for the original system is given based on the above Kalman filter by recursive Riccati equations, and a numerical example is presented to show the validity and efficiency of the proposed approach, where the comparison between the filter and predictor is also given.

  19. Dialysis search filters for PubMed, Ovid MEDLINE, and Embase databases.

    Science.gov (United States)

    Iansavichus, Arthur V; Haynes, R Brian; Lee, Christopher W C; Wilczynski, Nancy L; McKibbon, Ann; Shariff, Salimah Z; Blake, Peter G; Lindsay, Robert M; Garg, Amit X

    2012-10-01

    Physicians frequently search bibliographic databases, such as MEDLINE via PubMed, for best evidence for patient care. The objective of this study was to develop and test search filters to help physicians efficiently retrieve literature related to dialysis (hemodialysis or peritoneal dialysis) from all other articles indexed in PubMed, Ovid MEDLINE, and Embase. A diagnostic test assessment framework was used to develop and test robust dialysis filters. The reference standard was a manual review of the full texts of 22,992 articles from 39 journals to determine whether each article contained dialysis information. Next, 1,623,728 unique search filters were developed, and their ability to retrieve relevant articles was evaluated. The high-performance dialysis filters consisted of up to 65 search terms in combination. These terms included the words "dialy" (truncated), "uremic," "catheters," and "renal transplant wait list." These filters reached peak sensitivities of 98.6% and specificities of 98.5%. The filters' performance remained robust in an independent validation subset of articles. These empirically derived and validated high-performance search filters should enable physicians to effectively retrieve dialysis information from PubMed, Ovid MEDLINE, and Embase.

  20. Switching non-local vector median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2016-04-01

    This paper describes a novel image filtering method that removes random-valued impulse noise superimposed on a natural color image. In impulse noise removal, it is essential to employ a switching-type filtering method, as used in the well-known switching median filter, to preserve the detail of an original image with good quality. In color image filtering, it is generally preferable to deal with the red (R), green (G), and blue (B) components of each pixel of a color image as elements of a vectorized signal, as in the well-known vector median filter, rather than as component-wise signals to prevent a color shift after filtering. By taking these fundamentals into consideration, we propose a switching-type vector median filter with non-local processing that mainly consists of a noise detector and a noise removal filter. Concretely, we propose a noise detector that proactively detects noise-corrupted pixels by focusing attention on the isolation tendencies of pixels of interest not in an input image but in difference images between RGB components. Furthermore, as the noise removal filter, we propose an extended version of the non-local median filter, we proposed previously for grayscale image processing, named the non-local vector median filter, which is designed for color image processing. The proposed method realizes a superior balance between the preservation of detail and impulse noise removal by proactive noise detection and non-local switching vector median filtering, respectively. The effectiveness and validity of the proposed method are verified in a series of experiments using natural color images.

  1. Validation of the new filters configuration for the RPC gas systems at LHC experiments

    CERN Document Server

    Mandelli, Beatrice; Guida, Roberto; Hahn, Ferdinand; Haider, Stefan

    2012-01-01

    Resistive Plate Chambers (RPCs) are widely employed as muon trigger systems at the Large Hadron Collider (LHC) experiments. Their large detector volume and the use of a relatively expensive gas mixture make a closed-loop gas circulation unavoidable. The return gas of RPCs operated in conditions similar to the experimental background foreseen at LHC contains large amount of impurities potentially dangerous for long-term operation. Several gas-cleaning agents, characterized during the past years, are currently in use. New test allowed understanding of the properties and performance of a large number of purifiers. On that basis, an optimal combination of different filters consisting of Molecular Sieve (MS) 5Å and 4Å, and a Cu catalyst R11 has been chosen and validated irradiating a set of RPCs at the CERN Gamma Irradiation Facility (GIF) for several years. A very important feature of this new configuration is the increase of the cycle duration for each purifier, which results in better system stabilit...

  2. Influence of size, shape, and flexibility on bacterial passage through micropore membrane filters.

    Science.gov (United States)

    Wang, Yingying; Hammes, Frederik; Düggelin, Marcel; Egli, Thomas

    2008-09-01

    Sterilization of fluids by means of microfiltration is commonly applied in research laboratories as well as in pharmaceutical and industrial processes. Sterile micropore filters are subject to microbiological validation, where Brevundimonas diminuta is used as a standard test organism. However, several recent reports on the ubiquitous presence of filterable bacteria in aquatic environments have cast doubt on the accuracy and validity of the standard filter-testing method. Six different bacterial species of various sizes and shapes (Hylemonella gracilis, Escherichia coli, Sphingopyxis alaskensis, Vibrio cholerae, Legionella pneumophila, and B. diminuta) were tested for their filterability through sterile micropore filters. In all cases, the slender spirillum-shaped Hylemonella gracilis cells showed a superior ability to pass through sterile membrane filters. Our results provide solid evidence that the overall shape (including flexibility), instead of biovolume, is the determining factor for the filterability of bacteria, whereas cultivation conditions also play a crucial role. Furthermore, the filtration volume has a more important effect on the passage percentage in comparison with other technical variables tested (including flux and filter material). Based on our findings, we recommend a re-evaluation of the grading system for sterile filters, and suggest that the species Hylemonella should be considered as an alternative filter-testing organism for the quality assessment of micropore filters.

  3. An Unbiased Unscented Transform Based Kalman Filter for 3D Radar

    Institute of Scientific and Technical Information of China (English)

    WANGGuohong; XIUJianjuan; HEYou

    2004-01-01

    As a derivative-free alternative to the Extended Kalman filter (EKF) in the framework of state estimation, the Unscented Kalman filter (UKF) has potential applications in nonlinear filtering. By noting the fact that the unscented transform is generally biased when converting the radar measurements from spherical coordinates into Cartesian coordinates, a new filtering algorithm for 3D radar, called Unbiased unscented Kalman filter (UUKF), is proposed. The new algorithm is validated by Monte Carlo simulation runs. Simulation results show that the UUKF is more effective than the UKF, EKF and the Converted measurement Kalman filter (CMKF).

  4. Effectiveness in practice-based research: Looking for alternatives to the randomized controlled trial (RCT)

    NARCIS (Netherlands)

    Tavecchio, L.

    2015-01-01

    Over the last decade, the status of the randomized controlled trial (RCT), hallmark of evidence-based medicine (research), has been growing strongly in general practice, social work and public health. But this type of research is only practicable under strictly controlled and well-defined settings

  5. Personality Trait and Facial Expression Filter-Based Brain-Computer Interface

    Directory of Open Access Journals (Sweden)

    Seongah Chin

    2013-02-01

    Full Text Available In this paper, we present technical approaches that bridge the gap in the research related to the use of brain-computer interfaces for entertainment and facial expressions. Such facial expressions that reflect an individual's personal traits can be used to better realize artificial facial expressions in a gaming environment based on a brain-computer interface. First, an emotion extraction filter is introduced in order to classify emotions on the basis of the users' brain signals in real time. Next, a personality trait filter is defined to classify extrovert and introvert types, which manifest as five traits: very extrovert, extrovert, medium, introvert and very introvert. In addition, facial expressions derived from expression rates are obtained by an extrovert-introvert fuzzy model through its defuzzification process. Finally, we confirm this validation via an analysis of the variance of the personality trait filter, a k-fold cross validation of the emotion extraction filter, an accuracy analysis, a user study of facial synthesis and a test case game.

  6. Design of an S band narrow-band bandpass BAW filter

    Science.gov (United States)

    Gao, Yang; Zhao, Kun-li; Han, Chao

    2017-11-01

    An S band narrowband bandpass filter BAW with center frequency 2.460 GHz, bandwidth 41MHz, band insertion loss - 1.154 dB, the passband ripple 0.9 dB, the out of band rejection about -42.5dB@2.385 GHz; -45.5dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, the design is as follows: each FBAR's stack was designed in BAW filter by using Mason model. Each FBAR's shape was designed with the method of apodization electrode. The layout of BAW filter was designed. The acoustic-electromagnetic cosimulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and there are two characteristics: 1) an A and EM co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time; 2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and output necessary in-plane geometry information to the A and EM cosimulation model.

  7. Multi-template Scale-Adaptive Kernelized Correlation Filters

    KAUST Repository

    Bibi, Adel Aamer

    2015-12-07

    This paper identifies the major drawbacks of a very computationally efficient and state-of-the-art-tracker known as the Kernelized Correlation Filter (KCF) tracker. These drawbacks include an assumed fixed scale of the target in every frame, as well as, a heuristic update strategy of the filter taps to incorporate historical tracking information (i.e. simple linear combination of taps from the previous frame). In our approach, we update the scale of the tracker by maximizing over the posterior distribution of a grid of scales. As for the filter update, we prove and show that it is possible to use all previous training examples to update the filter taps very efficiently using fixed-point optimization. We validate the efficacy of our approach on two tracking datasets, VOT2014 and VOT2015.

  8. Multi-template Scale-Adaptive Kernelized Correlation Filters

    KAUST Repository

    Bibi, Adel Aamer; Ghanem, Bernard

    2015-01-01

    This paper identifies the major drawbacks of a very computationally efficient and state-of-the-art-tracker known as the Kernelized Correlation Filter (KCF) tracker. These drawbacks include an assumed fixed scale of the target in every frame, as well as, a heuristic update strategy of the filter taps to incorporate historical tracking information (i.e. simple linear combination of taps from the previous frame). In our approach, we update the scale of the tracker by maximizing over the posterior distribution of a grid of scales. As for the filter update, we prove and show that it is possible to use all previous training examples to update the filter taps very efficiently using fixed-point optimization. We validate the efficacy of our approach on two tracking datasets, VOT2014 and VOT2015.

  9. The discrete Kalman filtering approach for seismic signals deconvolution

    International Nuclear Information System (INIS)

    Kurniadi, Rizal; Nurhandoko, Bagus Endar B.

    2012-01-01

    Seismic signals are a convolution of reflectivity and seismic wavelet. One of the most important stages in seismic data processing is deconvolution process; the process of deconvolution is inverse filters based on Wiener filter theory. This theory is limited by certain modelling assumptions, which may not always valid. The discrete form of the Kalman filter is then used to generate an estimate of the reflectivity function. The main advantage of Kalman filtering is capability of technique to handling continually time varying models and has high resolution capabilities. In this work, we use discrete Kalman filter that it was combined with primitive deconvolution. Filtering process works on reflectivity function, hence the work flow of filtering is started with primitive deconvolution using inverse of wavelet. The seismic signals then are obtained by convoluting of filtered reflectivity function with energy waveform which is referred to as the seismic wavelet. The higher frequency of wavelet gives smaller wave length, the graphs of these results are presented.

  10. Design of Microwave Multibandpass Filters with Quasilumped Resonators

    Directory of Open Access Journals (Sweden)

    Dejan Miljanović

    2015-01-01

    Full Text Available Design of RF and microwave filters has always been the challenging engineering field. Modern filter design techniques involve the use of the three-dimensional electromagnetic (3D EM solvers for predicting filter behavior, yielding the most accurate filter characteristics. However, the 3D EM simulations are time consuming. In this paper, we propose electric-circuit models, instead of 3D EM models, suitable for design of RF and microwave filters with quasilumped coupled resonators. Using the diakoptic approach, the 3D filter structure is decomposed into domains that are modeled by electric networks. The coupling between these domains is modeled by capacitors and coupled inductors. Furthermore, we relate the circuit-element values to the physical dimensions of the 3D filter structure. We propose the filter design procedure that is based on the circuit models and fast circuit-level simulations, yielding the element values from which the physical dimensions can be obtained. The obtained dimensions should be slightly refined for achieving the desired filter characteristics. The mathematical problems encountered in the procedure are solved by numerical and symbolic computations. The procedure is exemplified by designing a triple-bandpass filter and validated by measurements on the fabricated filter. The simulation and experimental results are in good agreement.

  11. Removal of xenotropic murine leukemia virus by nanocellulose based filter paper.

    Science.gov (United States)

    Asper, M; Hanrieder, T; Quellmalz, A; Mihranyan, A

    2015-11-01

    The removal of xenotrpic murine leukemia virus (xMuLV) by size-exclusion filter paper composed of 100% naturally derived cellulose was validated. The filter paper was produced using cellulose nanofibers derived from Cladophora sp. algae. The filter paper was characterized using atomic force microscopy, scanning electron microscopy, helium pycnometry, and model tracer (100 nm latex beads and 50 nm gold nanoparticles) retention tests. Following the filtration of xMuLV spiked solutions, LRV ≥5.25 log10 TCID50 was observed, as limited by the virus titre in the feed solution and sensitivity of the tissue infectivity test. The results of the validation study suggest that the nanocellulose filter paper is useful for removal of endogenous rodent retroviruses and retrovirus-like particles during the production of recombinant proteins. Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  12. Exploratory RCT of art therapy as an adjunctive treatment in schizophrenia

    OpenAIRE

    Richardson, Phil; Jones, Kevin; Evans, Chris; Stevens, Peter; Rowe, Anna; HASH(0x7f4d76f6c120)

    2007-01-01

    Background\\ud There is no high quality controlled trial evidence for the effectiveness of art therapy in the adjunctive treatment of schizophrenia.\\ud \\ud Aims\\ud To conduct the first exploratory RCT of group interactive art therapy (AT) as an adjunctive treatment in chronic schizophrenia.\\ud \\ud Method\\ud The outcomes of 43 patients randomised to 12 sessions of AT were compared with those of 47 who received standard psychiatric care. Patients were assessed on a range of measures of symptoms,...

  13. Modeling, simulation, and design of SAW grating filters

    Science.gov (United States)

    Schwelb, Otto; Adler, E. L.; Slaboszewicz, J. K.

    1990-05-01

    A systematic procedure for modeling, simulating, and designing SAW (surface acoustic wave) grating filters, taking losses into account, is described. Grating structures and IDTs (interdigital transducers) coupling to SAWs are defined by cascadable transmission-matrix building blocks. Driving point and transfer characteristics (immittances) of complex architectures consisting of gratings, transducers, and coupling networks are obtained by chain-multiplying building-block matrices. This modular approach to resonator filter analysis and design combines the elements of lossy filter synthesis with the transmission-matrix description of SAW components. A multipole filter design procedure based on a lumped-element-model approximation of one-pole two-port resonator building blocks is given and the range of validity of this model examined. The software for simulating the performance of SAW grating devices based on this matrix approach is described, and its performance, when linked to the design procedure to form a CAD/CAA (computer-aided design and analysis) multiple-filter design package, is illustrated with a resonator filter design example.

  14. Artificial neural network (ANN)-based prediction of depth filter loading capacity for filter sizing.

    Science.gov (United States)

    Agarwal, Harshit; Rathore, Anurag S; Hadpe, Sandeep Ramesh; Alva, Solomon J

    2016-11-01

    This article presents an application of artificial neural network (ANN) modelling towards prediction of depth filter loading capacity for clarification of a monoclonal antibody (mAb) product during commercial manufacturing. The effect of operating parameters on filter loading capacity was evaluated based on the analysis of change in the differential pressure (DP) as a function of time. The proposed ANN model uses inlet stream properties (feed turbidity, feed cell count, feed cell viability), flux, and time to predict the corresponding DP. The ANN contained a single output layer with ten neurons in hidden layer and employed a sigmoidal activation function. This network was trained with 174 training points, 37 validation points, and 37 test points. Further, a pressure cut-off of 1.1 bar was used for sizing the filter area required under each operating condition. The modelling results showed that there was excellent agreement between the predicted and experimental data with a regression coefficient (R 2 ) of 0.98. The developed ANN model was used for performing variable depth filter sizing for different clarification lots. Monte-Carlo simulation was performed to estimate the cost savings by using different filter areas for different clarification lots rather than using the same filter area. A 10% saving in cost of goods was obtained for this operation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1436-1443, 2016. © 2016 American Institute of Chemical Engineers.

  15. Robust non-local median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2017-04-01

    This paper describes a novel image filter with superior performance on detail-preserving removal of random-valued impulse noise superimposed on natural gray-scale images. The non-local means filter is in the limelight as a way of Gaussian noise removal with superior performance on detail preservation. By referring the fundamental concept of the non-local means, we had proposed a non-local median filter as a specialized way for random-valued impulse noise removal so far. In the non-local processing, the output of a filter is calculated from pixels in blocks which are similar to the block centered at a pixel of interest. As a result, aggressive noise removal is conducted without destroying the detailed structures in an original image. However, the performance of non-local processing decreases enormously in the case of high noise occurrence probability. A cause of this problem is that the superimposed noise disturbs accurate calculation of the similarity between the blocks. To cope with this problem, we propose an improved non-local median filter which is robust to the high level of corruption by introducing a new similarity measure considering possibility of being the original signal. The effectiveness and validity of the proposed method are verified in a series of experiments using natural gray-scale images.

  16. Comparative analysis on some spatial-domain filters for fringe pattern denoising.

    Science.gov (United States)

    Wang, Haixia; Kemao, Qian

    2011-04-20

    Fringe patterns produced by various optical interferometric techniques encode information such as shape, deformation, and refractive index. Noise affects further processing of the fringe patterns. Denoising is often needed before fringe pattern demodulation. Filtering along the fringe orientation is an effective option. Such filters include coherence enhancing diffusion, spin filtering with curve windows, second-order oriented partial-differential equations, and the regularized quadratic cost function for oriented fringe pattern filtering. These filters are analyzed to establish the relationships among them. Theoretical analysis shows that the four filters are largely equivalent to each other. Quantitative results are given on simulated fringe patterns to validate the theoretical analysis and to compare the performance of these filters. © 2011 Optical Society of America

  17. Eulerian Time-Domain Filtering for Spatial LES

    Science.gov (United States)

    Pruett, C. David

    1997-01-01

    Eulerian time-domain filtering seems to be appropriate for LES (large eddy simulation) of flows whose large coherent structures convect approximately at a common characteristic velocity; e.g., mixing layers, jets, and wakes. For these flows, we develop an approach to LES based on an explicit second-order digital Butterworth filter, which is applied in,the time domain in an Eulerian context. The approach is validated through a priori and a posteriori analyses of the simulated flow of a heated, subsonic, axisymmetric jet.

  18. OvidSP Medline-to-PubMed search filter translation: a methodology for extending search filter range to include PubMed's unique content.

    Science.gov (United States)

    Damarell, Raechel A; Tieman, Jennifer J; Sladek, Ruth M

    2013-07-02

    PubMed translations of OvidSP Medline search filters offer searchers improved ease of access. They may also facilitate access to PubMed's unique content, including citations for the most recently published biomedical evidence. Retrieving this content requires a search strategy comprising natural language terms ('textwords'), rather than Medical Subject Headings (MeSH). We describe a reproducible methodology that uses a validated PubMed search filter translation to create a textword-only strategy to extend retrieval to PubMed's unique heart failure literature. We translated an OvidSP Medline heart failure search filter for PubMed and established version equivalence in terms of indexed literature retrieval. The PubMed version was then run within PubMed to identify citations retrieved by the filter's MeSH terms (Heart failure, Left ventricular dysfunction, and Cardiomyopathy). It was then rerun with the same MeSH terms restricted to searching on title and abstract fields (i.e. as 'textwords'). Citations retrieved by the MeSH search but not the textword search were isolated. Frequency analysis of their titles/abstracts identified natural language alternatives for those MeSH terms that performed less effectively as textwords. These terms were tested in combination to determine the best performing search string for reclaiming this 'lost set'. This string, restricted to searching on PubMed's unique content, was then combined with the validated PubMed translation to extend the filter's performance in this database. The PubMed heart failure filter retrieved 6829 citations. Of these, 834 (12%) failed to be retrieved when MeSH terms were converted to textwords. Frequency analysis of the 834 citations identified five high frequency natural language alternatives that could improve retrieval of this set (cardiac failure, cardiac resynchronization, left ventricular systolic dysfunction, left ventricular diastolic dysfunction, and LV dysfunction). Together these terms reclaimed

  19. Open source deformable image registration system for treatment planning and recurrence CT scans. Validation in the head and neck region

    International Nuclear Information System (INIS)

    Zukauskaite, Ruta; Brink, Carsten; Hansen, Christian Roenn; Bertelsen, Anders; Johansen, Joergen; Eriksen, Jesper Grau; Grau, Cai

    2016-01-01

    Clinical application of deformable registration (DIR) of medical images remains limited due to sparse validation of DIR methods in specific situations, e. g. in case of cancer recurrences. In this study the accuracy of DIR for registration of planning CT (pCT) and recurrence CT (rCT) images of head and neck squamous cell carcinoma (HNSCC) patients was evaluated. Twenty patients treated with definitive IMRT for HNSCC in 2010-2012 were included. For each patient, a pCT and an rCT scan were used. Median interval between the scans was 8.5 months. One observer manually contoured eight anatomical regions-of-interest (ROI) twice on pCT and once on rCT. pCT and rCT images were deformably registered using the open source software elastix. Mean surface distance (MSD) and Dice similarity coefficient (DSC) between contours were used for validation of DIR. A measure for delineation uncertainty was estimated by assessing MSD from the re-delineations of the same ROI on pCT. DIR and manual contouring uncertainties were correlated with tissue volume and rigidity. MSD varied 1-3 mm for different ROIs for DIR and 1-1.5 mm for re-delineated ROIs performed on pCT. DSC for DIR varied between 0.58 and 0.79 for soft tissues and was 0.79 or higher for bony structures, and correlated with the volumes of ROIs (r = 0.5, p < 0.001) and tissue rigidity (r = 0.54, p < 0.001). DIR using elastix in HNSCC on planning and recurrence CT scans is feasible; an uncertainty of the method is close to the voxel size length of the planning CT images. (orig.) [de

  20. Open source deformable image registration system for treatment planning and recurrence CT scans : Validation in the head and neck region.

    Science.gov (United States)

    Zukauskaite, Ruta; Brink, Carsten; Hansen, Christian Rønn; Bertelsen, Anders; Johansen, Jørgen; Grau, Cai; Eriksen, Jesper Grau

    2016-08-01

    Clinical application of deformable registration (DIR) of medical images remains limited due to sparse validation of DIR methods in specific situations, e. g. in case of cancer recurrences. In this study the accuracy of DIR for registration of planning CT (pCT) and recurrence CT (rCT) images of head and neck squamous cell carcinoma (HNSCC) patients was evaluated. Twenty patients treated with definitive IMRT for HNSCC in 2010-2012 were included. For each patient, a pCT and an rCT scan were used. Median interval between the scans was 8.5 months. One observer manually contoured eight anatomical regions-of-interest (ROI) twice on pCT and once on rCT. pCT and rCT images were deformably registered using the open source software elastix. Mean surface distance (MSD) and Dice similarity coefficient (DSC) between contours were used for validation of DIR. A measure for delineation uncertainty was estimated by assessing MSD from the re-delineations of the same ROI on pCT. DIR and manual contouring uncertainties were correlated with tissue volume and rigidity. MSD varied 1-3 mm for different ROIs for DIR and 1-1.5 mm for re-delineated ROIs performed on pCT. DSC for DIR varied between 0.58 and 0.79 for soft tissues and was 0.79 or higher for bony structures, and correlated with the volumes of ROIs (r = 0.5, p elastix in HNSCC on planning and recurrence CT scans is feasible; an uncertainty of the method is close to the voxel size length of the planning CT images.

  1. Motivation Filtering on a Multi-Institution Assessment of General College Outcomes

    Science.gov (United States)

    Steedle, Jeffrey T.

    2014-01-01

    Possible lack of motivation is a perpetual concern when tests have no stakes attached to performance. Specifically, the validity of test score interpretations may be compromised when examinees are unmotivated to exert their best efforts. Motivation filtering, a procedure that filters out apparently unmotivated examinees, was applied to the…

  2. Alles Kidzzz: RCT naar een preventieve geïndiceerde individuele interventie voor agressie op de basisschool

    NARCIS (Netherlands)

    Stoltz, S.E.M.J.; Londen, M. van; Dekovic, M.; Orobio de Castro, B.; Prinzie, P.

    2013-01-01

    For elementary schoolchildren with aggressive behaviour, there is a need for effective preventive interventions to interrupt the development towards more serious behaviour problems. This rct study evaluated the effects of an indicated preventive individualized school-based intervention (Stay Cool

  3. Gating Techniques for Rao-Blackwellized Monte Carlo Data Association Filter

    Directory of Open Access Journals (Sweden)

    Yazhao Wang

    2014-01-01

    Full Text Available This paper studies the Rao-Blackwellized Monte Carlo data association (RBMCDA filter for multiple target tracking. The elliptical gating strategies are redesigned and incorporated into the framework of the RBMCDA filter. The obvious benefit is the reduction of the time cost because the data association procedure can be carried out with less validated measurements. In addition, the overlapped parts of the neighboring validation regions are divided into several separated subregions according to the possible origins of the validated measurements. In these subregions, the measurement uncertainties can be taken into account more reasonably than those of the simple elliptical gate. This would help to achieve higher tracking ability of the RBMCDA algorithm by a better association prior approximation. Simulation results are provided to show the effectiveness of the proposed gating techniques.

  4. Spirometry filters can be used to detect exhaled respiratory viruses.

    Science.gov (United States)

    Mitchell, Alicia B; Mourad, Bassel; Tovey, Euan; Buddle, Lachlan; Peters, Matthew; Morgan, Lucy; Oliver, Brian G

    2016-09-26

    Respiratory viruses are very common in the community and contribute to the burden of illness for patients with chronic respiratory diseases, including acute exacerbations. Traditional sampling methods are invasive and problematic to repeat. Accordingly, we explored whether respiratory viruses could be isolated from disposable spirometry filters and whether detection of viruses in this context represented presence in the upper or lower respiratory tract. Discovery (n  =  53) and validation (n  =  49) cohorts were recruited from a hospital outpatient department during two different time periods. Spirometry mouthpiece filters were collected from all participants. Respiratory secretions were sampled from the upper and lower respiratory tract by nasal washing (NW), sputum, and bronchoalveolar lavage (BAL). All samples were examined using RT-PCR to identify a panel of respiratory viruses (rhinovirus, respiratory syncytial virus, influenza A, influenza B, parainfluenza virus 1, 2 & 3, and human metapneumovirus). Rhinovirus was quantified using qPCR. Paired filter-NW samples (n  =  29), filter-sputum samples (n  =  24), filter-BAL samples (n  =  39) and filter-NW-BAL samples (n  =  10) provided a range of comparisons. At least one virus was detected in any sample in 85% of participants in the discovery cohort versus 45% in the validation cohort. Overall, 72% of viruses identified in the paired comparator method matched those detected in spirometry filters. There was a high correlation between viruses identified in spirometry filters compared with viruses identified in both the upper and lower respiratory tract using traditional sampling methods. Our results suggest that examination of spirometry filters may be a novel and inexpensive sampling method for the presence of respiratory viruses in exhaled breath.

  5. Q-Method Extended Kalman Filter

    Science.gov (United States)

    Zanetti, Renato; Ainscough, Thomas; Christian, John; Spanos, Pol D.

    2012-01-01

    A new algorithm is proposed that smoothly integrates non-linear estimation of the attitude quaternion using Davenport s q-method and estimation of non-attitude states through an extended Kalman filter. The new method is compared to a similar existing algorithm showing its similarities and differences. The validity of the proposed approach is confirmed through numerical simulations.

  6. Fast algorithm for Morphological Filters

    International Nuclear Information System (INIS)

    Lou Shan; Jiang Xiangqian; Scott, Paul J

    2011-01-01

    In surface metrology, morphological filters, which evolved from the envelope filtering system (E-system) work well for functional prediction of surface finish in the analysis of surfaces in contact. The naive algorithms are time consuming, especially for areal data, and not generally adopted in real practice. A fast algorithm is proposed based on the alpha shape. The hull obtained by rolling the alpha ball is equivalent to the morphological opening/closing in theory. The algorithm depends on Delaunay triangulation with time complexity O(nlogn). In comparison to the naive algorithms it generates the opening and closing envelope without combining dilation and erosion. Edge distortion is corrected by reflective padding for open profiles/surfaces. Spikes in the sample data are detected and points interpolated to prevent singularities. The proposed algorithm works well both for morphological profile and area filters. Examples are presented to demonstrate the validity and superiority on efficiency of this algorithm over the naive algorithm.

  7. Ella-V and technology usage technology usage in an english language and literacy acquisition validation randomized controlled trial study

    OpenAIRE

    Roisin P. Corcoran; Steven M. Ross; Beverly J. Irby; Fuhui Tong; Rafael Lara-Alecio; Cindy Guerrero

    2014-01-01

    This paper describes the use of technology to provide virtual professional development (VPD) for teachers and to conduct classroom observations in a study of English Language Learner (ELL) instruction in grades K–3. The technology applications were part of a cluster randomized control trial (RCT) design for a federally funded longitudinal validation study of a particular program, English Language and Literacy Acquisition-Validation, ELLA- V, to determine its degree of impact on English oral l...

  8. The effect of parental involvement in CBT of anxious children: Preliminary results from a RCT study

    DEFF Research Database (Denmark)

    Esbjørn, Barbara Hoff; Breinholst, Sonja; Reinholdt-Dunne, Marie Louise

    2011-01-01

    Esbjørn, B. H., Breinholst, S., Reinholdt-Dunne, M. L., & Leth, I. (2011). The effect of parental involvement in CBT of anxious children: Preliminary results from a RCT study. Poster accepted for the Association for Behavioral and Cognitive Therapies, Toronto, Canada....

  9. Feature-Based Nonlocal Polarimetric SAR Filtering

    Directory of Open Access Journals (Sweden)

    Xiaoli Xing

    2017-10-01

    Full Text Available Polarimetric synthetic aperture radar (PolSAR images are inherently contaminated by multiplicative speckle noise, which complicates the image interpretation and image analyses. To reduce the speckle effect, several adaptive speckle filters have been developed based on the weighted average of the similarity measures commonly depending on the model or probability distribution, which are often affected by the distribution parameters and modeling texture components. In this paper, a novel filtering method introduces the coefficient of variance ( CV and Pauli basis (PB to measure the similarity, and the two features are combined with the framework of the nonlocal mean filtering. The CV is used to describe the complexity of various scenes and distinguish the scene heterogeneity; moreover, the Pauli basis is able to express the polarimetric information in PolSAR image processing. This proposed filtering combines the CV and Pauli basis to improve the estimation accuracy of the similarity weights. Then, the similarity of the features is deduced according to the test statistic. Subsequently, the filtering is proceeded by using the nonlocal weighted estimation. The performance of the proposed filter is tested with the simulated images and real PolSAR images, which are acquired by AIRSAR system and ESAR system. The qualitative and quantitative experiments indicate the validity of the proposed method by comparing with the widely-used despeckling methods.

  10. Michelson interferometer based interleaver design using classic IIR filter decomposition.

    Science.gov (United States)

    Cheng, Chi-Hao; Tang, Shasha

    2013-12-16

    An elegant method to design a Michelson interferometer based interleaver using a classic infinite impulse response (IIR) filter such as Butterworth, Chebyshev, and elliptic filters as a starting point are presented. The proposed design method allows engineers to design a Michelson interferometer based interleaver from specifications seamlessly. Simulation results are presented to demonstrate the validity of the proposed design method.

  11. High-performance information search filters for CKD content in PubMed, Ovid MEDLINE, and EMBASE.

    Science.gov (United States)

    Iansavichus, Arthur V; Hildebrand, Ainslie M; Haynes, R Brian; Wilczynski, Nancy L; Levin, Adeera; Hemmelgarn, Brenda R; Tu, Karen; Nesrallah, Gihad E; Nash, Danielle M; Garg, Amit X

    2015-01-01

    Finding relevant articles in large bibliographic databases such as PubMed, Ovid MEDLINE, and EMBASE to inform care and future research is challenging. Articles relevant to chronic kidney disease (CKD) are particularly difficult to find because they are often published under different terminology and are found across a wide range of journal types. We used computer automation within a diagnostic test assessment framework to develop and validate information search filters to identify CKD articles in large bibliographic databases. 22,992 full-text articles in PubMed, Ovid MEDLINE, or EMBASE. 1,374,148 unique search filters. We established the reference standard of article relevance to CKD by manual review of all full-text articles using prespecified criteria to determine whether each article contained CKD content or not. We then assessed filter performance by calculating sensitivity, specificity, and positive predictive value for the retrieval of CKD articles. Filters with high sensitivity and specificity for the identification of CKD articles in the development phase (two-thirds of the sample) were then retested in the validation phase (remaining one-third of the sample). We developed and validated high-performance CKD search filters for each bibliographic database. Filters optimized for sensitivity reached at least 99% sensitivity, and filters optimized for specificity reached at least 97% specificity. The filters were complex; for example, one PubMed filter included more than 89 terms used in combination, including "chronic kidney disease," "renal insufficiency," and "renal fibrosis." In proof-of-concept searches, physicians found more articles relevant to the topic of CKD with the use of these filters. As knowledge of the pathogenesis of CKD grows and definitions change, these filters will need to be updated to incorporate new terminology used to index relevant articles. PubMed, Ovid MEDLINE, and EMBASE can be filtered reliably for articles relevant to CKD. These

  12. Kalman and particle filtering methods for full vehicle and tyre identification

    Science.gov (United States)

    Bogdanski, Karol; Best, Matthew C.

    2018-05-01

    This paper considers identification of all significant vehicle handling dynamics of a test vehicle, including identification of a combined-slip tyre model, using only those sensors currently available on most vehicle controller area network buses. Using an appropriately simple but efficient model structure, all of the independent parameters are found from test vehicle data, with the resulting model accuracy demonstrated on independent validation data. The paper extends previous work on augmented Kalman Filter state estimators to concentrate wholly on parameter identification. It also serves as a review of three alternative filtering methods; identifying forms of the unscented Kalman filter, extended Kalman filter and particle filter are proposed and compared for effectiveness, complexity and computational efficiency. All three filters are suited to applications of system identification and the Kalman Filters can also operate in real-time in on-line model predictive controllers or estimators.

  13. Active pre-filters for dc/dc Boost regulators

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Ramos-Paja

    2014-05-01

    Full Text Available This paper proposes an active pre-filter to mitigate the current harmonics generated by classical dc/dc Boost regulators, which generate current ripples proportional to the duty cycle. Therefore, high output voltage conditions, i.e., high voltage conversion ratios, produce high current harmonics that must be filtered to avoid damage or source losses. Traditionally, these current components are filtered using electrolytic capacitors, which introduce reliability problems because of their high failure rate. The solution introduced in this paper instead uses a dc/dc converter based on the parallel connection of the Boost canonical cells to filter the current ripples generated by the Boost regulator, improving the system reliability. This solution provides the additional benefits of improving the overall efficiency and the voltage conversion ratio. Finally, the solution is validated with simulations and experimental results.

  14. Hybrid Active Filter with Variable Conductance for Harmonic Resonance Suppression in Industrial Power Systems

    DEFF Research Database (Denmark)

    Lee, Tzung-Lin; Wang, Yen-Ching; Li, Jian-Cheng

    2015-01-01

    Unintentional series and/or parallel resonances, due to the tuned passive filter and the line inductance, may result in severe harmonic distortion in the industrial power system. This paper presents a hybrid active filter to suppress harmonic resonance and reduce harmonic distortion as well...... expensive. A reasonable trade-off between filtering performances and cost is to use the hybrid active filter. Design consideration are presented and experimental results are provided to validate effectiveness of the proposed method. Furthermore, this paper discusses filtering performances on line impedance...

  15. Compact Unequal Power Divider with Filtering Response

    Directory of Open Access Journals (Sweden)

    Wei-Qiang Pan

    2015-01-01

    Full Text Available We present a novel unequal power divider with bandpass responses. The proposed power divider consists of five resonators and a resistor. The power division ratio is controlled by altering the coupling strength among the resonators. The output ports have the characteristic impedance of 50 Ω and impedance transformers in classical Wilkinson power dividers are not required in this design. Use of resonators enables the filtering function of the power divider. Two transmission zeros are generated near the passband edges, resulting in quasielliptic bandpass responses. For validation, a 2 : 1 filtering power divider is implemented. The fabricated circuit size is 0.22 λg × 0.08 λg, featuring compact size for unequal filtering power dividers, which is suitable for the feeding networks of antenna arrays.

  16. A systematic literature review of US definitions, scoring systems and validity according to the OMERACT filter for tendon lesion in RA and other inflammatory joint diseases.

    Science.gov (United States)

    Alcalde, María; D'Agostino, Maria Antonietta; Bruyn, George A W; Möller, Ingrid; Iagnocco, Annamaria; Wakefield, Richard J; Naredo, Esperanza

    2012-07-01

    To present the published data concerning the US assessment of tendon lesions as well as the US metric properties investigated in inflammatory arthritis. A systematic literature search of PubMed, Embase and the Cochrane Library was performed. Selection criteria were original articles in the English language reporting US, Doppler, tenosynovitis and other tendon lesions in patients with RA and other inflammatory arthritis. Data extraction focused on the definition and quantification of US-detected tenosynovitis and other tendon abnormalities and the metric properties of US according to the OMERACT filter for evaluating the above tendon lesions. Thirty-three of 192 identified articles were included in the review. Most articles were case series (42%) or case-control (33%) studies describing hand and/or foot tenosynovitis in RA patients. The majority of older articles used only B-mode, whereas the most recent studies have incorporated Doppler mode. Definition of tenosynovitis or other tendon lesion was provided in 70% of the evaluated studies. Most of the studies (61%) used a binary score for evaluating tendon abnormalities. Concerning the OMERACT filter, 24 (73%) articles dealt with construct validity. The comparator most commonly used was clinical assessment and MRI. There were few studies assessing criterion validity. Some studies evaluated reliability (36%), responsiveness (21%) and feasibility (12%). US seems a promising tool for evaluating inflammatory tendon lesions. However, further validation is necessary for implementation in clinical practice and trials.

  17. Neural Model for Left-Handed CPW Bandpass Filter Loaded Split Ring Resonator

    Science.gov (United States)

    Liu, Haiwen; Wang, Shuxin; Tan, Mingtao; Zhang, Qijun

    2010-02-01

    Compact left-handed coplanar waveguide (CPW) bandpass filter loaded split ring resonator (SRR) is presented in this paper. The proposed filter exhibits a quasi-elliptic function response and its circuit size occupies only 12 × 11.8 mm2 (≈0.21 λg × 0.20 λg). Also, a simple circuit model is given and the parametric study of this filter is discussed. Then, with the aid of NeuroModeler software, a five-layer feed-forward perceptron neural networks model is built up to optimize the proposed filter design fast and accurately. Finally, this newly left-handed CPW bandpass filter was fabricated and measured. A good agreement between simulations and measurement verifies the proposed left-handed filter and the validity of design methodology.

  18. Economic evaluation alongside a single RCT of an integrative psychotherapeutic nursing home programme.

    Science.gov (United States)

    Hakkaart-van Roijen, Leona; Bakker, Ton J E M; Al, Maiwenn; van der Lee, Jacqueline; Duivenvoorden, Hugo J; Ribbe, Miel W; Huijsman, Robbert

    2013-09-30

    There is an 80% prevalence of two or more psychiatric symptoms in psychogeriatric patients. Multiple psychiatric symptoms (MPS) have many negative effects on quality of life of the patient as well as on caregiver burden and competence. Irrespective of the effectiveness of an intervention programme, it is important to take into account its economic aspects. The economic evaluation was performed alongside a single open RCT and conducted between 2001 and 2006. The patients who met the selection criteria were asked to participate in the RCT. After the patient or his caregiver signed a written informed consent form, he was then randomly assigned to either IRR or UC.The costs and effects of IRR were compared to those of UC. We assessed the cost-utility of IRR as well as the cost-effectiveness of both conditions. Primary outcome variable: severity of MPS (NPI) of patients; secondary outcome variables: general caregiver burden (CB) and caregiver competence (CCL), quality of life (EQ5D) of the patient, and total medical costs per patient (TiC-P). Cost-utility was evaluated on the basis of differences in total medical costs). Cost-effectiveness was evaluated by comparing differences of total medical costs and effects on NPI, CB and CCL (Incremental Cost-Effectiveness Ratio: ICER). CEAC-analyses were performed for QALY and NPI-severity. All significant testing was fixed at pprinciple. A complete cases approach (CC) was used. IRR turned out to be non-significantly, 10.5% more expensive than UC (€ 36 per day). The number of QALYs was 0.01 higher (non-significant) in IRR, resulting in € 276,290 per QALY. According to the ICER-method, IRR was significantly more cost-effective on NPI-sum-severity of the patient (up to 34%), CB and CCL (up to 50%), with ICERs varying from € 130 to € 540 per additional point of improvement. No significant differences were found on QALYs. In IRR patients improved significantly more on severity of MPS, and caregivers on general burden and

  19. External Validity of Randomized Controlled Trials on Alzheimer’s Disease: The Biases of Frailty and Biological Aging

    Directory of Open Access Journals (Sweden)

    Marco Canevelli

    2017-11-01

    Full Text Available To date, the external validity of randomized controlled trials (RCTs on Alzheimer’s disease (AD has been assessed only considering monodimensional variables. Nevertheless, looking at isolated and single characteristics cannot guarantee a sufficient level of appreciation of the AD patients’ complexity. The only way to understand whether the two worlds (i.e., research and clinics deal with the same type of patients is to adopt multidimensional approaches more holistically reflecting the biological age of the individual. In the present study, we compared measures of frailty/biological aging [assessed by a Frailty Index (FI] of a sample of patients with AD resulted eligible and subsequently included in phase III RCTs compared to patients referring to the same clinical service, but not considered for inclusion. The “RCT sample” and the “real world sample” were found to be statistically similar for all the considered sociodemographic and clinical variables. Nevertheless, the “real world sample” was found to be significantly frailer compared to the “RCT sample,” as indicated by higher FI scores [0.28 (SD 0.1 vs. 0.17 (SD 0.1; p < 0.001, respectively]. Moreover, when assessing the relationship between FI and age, we found that the correlation was almost null in the “RCT sample” (Spearman’s r = 0.01; p = 0.98, while it was statistically significant in the “real world sample” (r = 0.49; p = 0.02. The application of too rigid designs may result in the poor representativeness of RCT samples. It may even imply the study of a condition biologically different from that observed in the “real world.” The adoption of multidimensional measures capable to capture the individual’s biological age may facilitate evaluating the external validity of clinical studies, implicitly improving the interpretation of the results and their translation in the clinical arena.

  20. Optimal Design of High-Order Passive-Damped Filters for Grid-Connected Applications

    DEFF Research Database (Denmark)

    Beres, Remus Narcis; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    Harmonic stability problems caused by the resonance of high-order filters in power electronic systems are ever increasing. The use of passive damping does provide a robust solution to address these issues, but at the price of reduced efficiency due to the presence of additional passive components....... Hence, a new method is proposed in this paper to optimally design the passive damping circuit for the LCL filters and LCL with multi-tuned LC traps. In short, the optimization problem reduces to the proper choice of the multi-split capacitors or inductors in the high-order filter. Compared to existing...... filter resonance. The passive filters are designed, built and validated both analytically and experimentally for verification....

  1. 640 Gbit/s RZ-to-NRZ format conversion based on optical phase filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Kong, Deming; Galili, Michael

    2014-01-01

    We propose a novel approach for all optical RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal using a simple phase filter implemented by a commercial optical waveshaper....

  2. Effectiveness of interim stage filter in the exhaust system of glove boxes

    International Nuclear Information System (INIS)

    Patre, D.K.; Vangara, H.; Thanamani, S.; Gopalakrishnan, R.K.; Mhatre, Amol M.

    2018-01-01

    All operations in radiochemical laboratories are carried out in containment systems like Glove boxes and Fume hoods. For controlling air contamination two separate air cleaning systems are incorporated. Laboratory has general ventilation system and glove boxes are provided with a negative pressure system (NPS). Glove box exhaust air is passed through three stage filtration systems: in situ, interim and final before discharging to the atmosphere. In addition to the individual HEPA filters of each glove box, there is an interim HEPA filter bank introduced at the laboratory end. This was introduced to reduce a load on main exhaust filter system. Finally the exhaust air is discharged through the final stage HEPA filter located in the filter house through the Stack. The interim HEPA filter bank provides additional protection for the release of particulate activity and reduces load on the final stage filters. In the present work efforts have been put to validate the interim stage filter, which has been introduced, to limit the environmental release

  3. Signal filtering algorithm for depth-selective diffuse optical topography

    International Nuclear Information System (INIS)

    Fujii, M; Nakayama, K

    2009-01-01

    A compact filtered backprojection algorithm that suppresses the undesirable effects of skin circulation for near-infrared diffuse optical topography is proposed. Our approach centers around a depth-selective filtering algorithm that uses an inverse problem technique and extracts target signals from observation data contaminated by noise from a shallow region. The filtering algorithm is reduced to a compact matrix and is therefore easily incorporated into a real-time system. To demonstrate the validity of this method, we developed a demonstration prototype for depth-selective diffuse optical topography and performed both computer simulations and phantom experiments. The results show that the proposed method significantly suppresses the noise from the shallow region with a minimal degradation of the target signal.

  4. Application of wavelet-based multi-model Kalman filters to real-time flood forecasting

    Science.gov (United States)

    Chou, Chien-Ming; Wang, Ru-Yih

    2004-04-01

    This paper presents the application of a multimodel method using a wavelet-based Kalman filter (WKF) bank to simultaneously estimate decomposed state variables and unknown parameters for real-time flood forecasting. Applying the Haar wavelet transform alters the state vector and input vector of the state space. In this way, an overall detail plus approximation describes each new state vector and input vector, which allows the WKF to simultaneously estimate and decompose state variables. The wavelet-based multimodel Kalman filter (WMKF) is a multimodel Kalman filter (MKF), in which the Kalman filter has been substituted for a WKF. The WMKF then obtains M estimated state vectors. Next, the M state-estimates, each of which is weighted by its possibility that is also determined on-line, are combined to form an optimal estimate. Validations conducted for the Wu-Tu watershed, a small watershed in Taiwan, have demonstrated that the method is effective because of the decomposition of wavelet transform, the adaptation of the time-varying Kalman filter and the characteristics of the multimodel method. Validation results also reveal that the resulting method enhances the accuracy of the runoff prediction of the rainfall-runoff process in the Wu-Tu watershed.

  5. Studies on signal validation and sensor surveillance for in-core signals in NPP

    International Nuclear Information System (INIS)

    Ciftcioglu, O.

    1991-12-01

    Signal validation and sensor failure detection are two essential tasks to be carried out continuously in an operating reactor. Towards this aim, an optimal filtering approach for in-core NPP signals is implemented. The method concerns the specific measured input signal information as a parameter state and they are estimated by means of Kalman filtering technique. The signal validation and sensor surveillance system comprise filters as many as the states being considered and each filter receives all the measured signals as inputs in such a way that each filter in hand is desensitized to one of the individual input signals relative to others. In case of no failure of sensors all the filter outputs are identical. Each sensor output is tested by means of corresponding estimate present at the output of that filter which is desensitized to the sensor being tested. The comparison test is carried out continuously in real-time and any significant deviation noted during the test process is identified to be a sensor failure together with the faulty sensor. The method is investigated by means of real plant data of the in-core neutron detectors and core-inlet and outlet thermocouples of the Borssele nuclear power plant. The method has proven to be effective for fast and reliable in-core sensor failure detection as well as for in-core signal validation in normal operation indicating its further effectiveness for model validation applications in nuclear power plants. (author). 17 refs.; 4 figs.; 1 tab

  6. Sensory Pollution from Bag Filters, Carbon Filters and Combinations

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

    2008-01-01

    by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter...... that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC...

  7. Walsh-synthesized noise filters for quantum logic

    International Nuclear Information System (INIS)

    Ball, Harrison; Biercuk, Michael J.

    2015-01-01

    We study a novel class of open-loop control protocols constructed to perform arbitrary nontrivial single-qubit logic operations robust against time-dependent non-Markovian noise. Amplitude and phase modulation protocols are crafted leveraging insights from functional synthesis and the basis set of Walsh functions. We employ the experimentally validated generalized filter-transfer function formalism in order to find optimized control protocols for target operations in SU(2) by defining a cost function for the filter-transfer function to be minimized through the applied modulation. Our work details the various techniques by which we define and then optimize the filter-synthesis process in the Walsh basis, including the definition of specific analytic design rules which serve to efficiently constrain the available synthesis space. This approach yields modulated-gate constructions consisting of chains of discrete pulse-segments of arbitrary form, whose modulation envelopes possess intrinsic compatibility with digital logic and clocking. We derive novel families of Walsh-modulated noise filters designed to suppress dephasing and coherent amplitude-damping noise, and describe how well-known sequences derived in NMR also fall within the Walsh-synthesis framework. Finally, our work considers the effects of realistic experimental constraints such as limited modulation bandwidth on achievable filter performance. (orig.)

  8. Walsh-synthesized noise filters for quantum logic

    Energy Technology Data Exchange (ETDEWEB)

    Ball, Harrison; Biercuk, Michael J. [The University of Sydney, ARC Centre for Engineered Quantum Systems, School of Physics, Sydney, NSW (Australia); National Measurement Institute, Sydney, NSW (Australia)

    2015-05-14

    We study a novel class of open-loop control protocols constructed to perform arbitrary nontrivial single-qubit logic operations robust against time-dependent non-Markovian noise. Amplitude and phase modulation protocols are crafted leveraging insights from functional synthesis and the basis set of Walsh functions. We employ the experimentally validated generalized filter-transfer function formalism in order to find optimized control protocols for target operations in SU(2) by defining a cost function for the filter-transfer function to be minimized through the applied modulation. Our work details the various techniques by which we define and then optimize the filter-synthesis process in the Walsh basis, including the definition of specific analytic design rules which serve to efficiently constrain the available synthesis space. This approach yields modulated-gate constructions consisting of chains of discrete pulse-segments of arbitrary form, whose modulation envelopes possess intrinsic compatibility with digital logic and clocking. We derive novel families of Walsh-modulated noise filters designed to suppress dephasing and coherent amplitude-damping noise, and describe how well-known sequences derived in NMR also fall within the Walsh-synthesis framework. Finally, our work considers the effects of realistic experimental constraints such as limited modulation bandwidth on achievable filter performance. (orig.)

  9. A CLT on the SNR of Diagonally Loaded MVDR Filters

    Science.gov (United States)

    Rubio, Francisco; Mestre, Xavier; Hachem, Walid

    2012-08-01

    This paper studies the fluctuations of the signal-to-noise ratio (SNR) of minimum variance distorsionless response (MVDR) filters implementing diagonal loading in the estimation of the covariance matrix. Previous results in the signal processing literature are generalized and extended by considering both spatially as well as temporarily correlated samples. Specifically, a central limit theorem (CLT) is established for the fluctuations of the SNR of the diagonally loaded MVDR filter, under both supervised and unsupervised training settings in adaptive filtering applications. Our second-order analysis is based on the Nash-Poincar\\'e inequality and the integration by parts formula for Gaussian functionals, as well as classical tools from statistical asymptotic theory. Numerical evaluations validating the accuracy of the CLT confirm the asymptotic Gaussianity of the fluctuations of the SNR of the MVDR filter.

  10. Cancellation of neutral current harmonics by using a four-branch star hybrid filter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Rodriguez, Pedro; Candela, I.

    2008-01-01

    filtering topology to a three-phase four-wire system. An extensive evaluation using simulation and experimental results are conducted in this work to validate the good performance of the proposed solution for canceling current harmonics flowing through the neutral conductor.......This paper presents a new technique for filtering current harmonics in three-phase four-wire networks based on the usage of a four-branch star (FBS) filter topology. Based on single-phase inductors and capacitors, the specific layout of the FBS filter topology allows achieving a power filter...... is improved by integrating a power converter into its structure. This paper analyzes the FBS topology and presents fundamental concepts regarding the control of a generic FBS hybrid power filter. A neutral current hybrid power filter and var compensator is presented as an illustrative example applying the FBS...

  11. A Novel CPW BandPass Filter Integrating Periodic Rectangular Slot Cells

    Directory of Open Access Journals (Sweden)

    Fouad Aytouna

    2015-12-01

    Full Text Available In this paper, we introduce the design and the achievement of a Bandpass filter structure based on the use of rectangular slot cell. The originality of this work is to achieve a coplanar filter easy to integrate with microwave planar circuits and having a wide frequency bandwidth. The proposed bandpass filter is a low cost and compact planar filter structure. The final circuit is simulated by using two electromagnetic solvers, ADS and HFSS. The validation into simulation is based on using optimization methods integrated into the both solvers. Simulations have taken into account a high meshing density to cover the whole circuit. The fabricated bandpass filter has an area of 35X31mm2 and having a good insertion loss around -0.75dB in the bandwidth. The comparison between simulation and measurement results presents a good agreement.

  12. Nondestructive quality assurance of ceramic filters using noncontact dynamic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yue, P.; Chen, S.E.; Nishihama, Y. [University of Alabama, Birmingham, AL (United States). Dept. of Civil & Environmental Engineering

    2005-06-01

    Ceramic candle filters are stiff cylindrical structures arranged in rosettes in a hot gas vessel. Custom-made with strong composite materials, these filters are designed to withstand heating and cooling cycles of very high temperature gradients during coal energy production processes. To ensure consistency in the manufactured filters, noncontact dynamic characterization using laser vibrometry is proposed as a factory quality control technique. To evaluate the proposed technique, a sensitivity study using both contact and noncontact vibration measurements is first conducted. The shift in natural vibration frequencies is used as a quality indicator for likely manufacturing variables. Six candle filters are tested using dynamic impact tests. Contact and noncontact results are compared with theoretical natural frequency values, which show that laser results were 'noisier' due to dropout from speckle noises. The results are used to establish the sensitivity of the technique, which indicates that dynamic characterization is a valid nondestructive testing technique for quality assurance of the ceramic filters, provided that the manufactured filters have a quality variation greater than 3.21%.

  13. [Numerical simulation and operation optimization of biological filter].

    Science.gov (United States)

    Zou, Zong-Sen; Shi, Han-Chang; Chen, Xiang-Qiang; Xie, Xiao-Qing

    2014-12-01

    BioWin software and two sensitivity analysis methods were used to simulate the Denitrification Biological Filter (DNBF) + Biological Aerated Filter (BAF) process in Yuandang Wastewater Treatment Plant. Based on the BioWin model of DNBF + BAF process, the operation data of September 2013 were used for sensitivity analysis and model calibration, and the operation data of October 2013 were used for model validation. The results indicated that the calibrated model could accurately simulate practical DNBF + BAF processes, and the most sensitive parameters were the parameters related to biofilm, OHOs and aeration. After the validation and calibration of model, it was used for process optimization with simulating operation results under different conditions. The results showed that, the best operation condition for discharge standard B was: reflux ratio = 50%, ceasing methanol addition, influent C/N = 4.43; while the best operation condition for discharge standard A was: reflux ratio = 50%, influent COD = 155 mg x L(-1) after methanol addition, influent C/N = 5.10.

  14. Grid Filter Design for a Multi-Megawatt Medium-Voltage Voltage Source Inverter

    DEFF Research Database (Denmark)

    Rockhill, A.A.; Liserre, Marco; Teodorescu, Remus

    2011-01-01

    This paper describes the design procedure and performance of an LCL grid filter for a medium-voltage neutral point clamped (NPC) converter to be adopted for a multimegawatt wind turbine. The unique filter design challenges in this application are driven by a combination of the medium voltage...... converter, a limited allowable switching frequency, component physical size and weight concerns, and the stringent limits for allowable injected current harmonics. Traditional design procedures of grid filters for lower power and higher switching frequency converters are not valid for a multi......-megawatt filter connecting a medium-voltage converter switching at low frequency to the electric grid. This paper demonstrates a frequency domain model based approach to determine the optimum filter parameters that provide the necessary performance under all operating conditions given the necessary design...

  15. Bit-rate-transparent optical RZ-to-NRZ format conversion based on linear spectral phase filtering

    DEFF Research Database (Denmark)

    Maram, Reza; Da Ros, Francesco; Guan, Pengyu

    2017-01-01

    We propose a novel and strikingly simple design for all-optical bit-rate-transparent RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal.......We propose a novel and strikingly simple design for all-optical bit-rate-transparent RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal....

  16. Filter arrays

    Science.gov (United States)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  17. Sampling strong tracking nonlinear unscented Kalman filter and its application in eye tracking

    International Nuclear Information System (INIS)

    Zu-Tao, Zhang; Jia-Shu, Zhang

    2010-01-01

    The unscented Kalman filter is a developed well-known method for nonlinear motion estimation and tracking. However, the standard unscented Kalman filter has the inherent drawbacks, such as numerical instability and much more time spent on calculation in practical applications. In this paper, we present a novel sampling strong tracking nonlinear unscented Kalman filter, aiming to overcome the difficulty in nonlinear eye tracking. In the above proposed filter, the simplified unscented transform sampling strategy with n + 2 sigma points leads to the computational efficiency, and suboptimal fading factor of strong tracking filtering is introduced to improve robustness and accuracy of eye tracking. Compared with the related unscented Kalman filter for eye tracking, the proposed filter has potential advantages in robustness, convergence speed, and tracking accuracy. The final experimental results show the validity of our method for eye tracking under realistic conditions. (classical areas of phenomenology)

  18. Digital timing: sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution

    International Nuclear Information System (INIS)

    Cho, Sanghee; Grazioso, Ron; Zhang Nan; Aykac, Mehmet; Schmand, Matthias

    2011-01-01

    The main focus of our study is to investigate how the performance of digital timing methods is affected by sampling rate, anti-aliasing and signal interpolation filters. We used the Nyquist sampling theorem to address some basic questions such as what will be the minimum sampling frequencies? How accurate will the signal interpolation be? How do we validate the timing measurements? The preferred sampling rate would be as low as possible, considering the high cost and power consumption of high-speed analog-to-digital converters. However, when the sampling rate is too low, due to the aliasing effect, some artifacts are produced in the timing resolution estimations; the shape of the timing profile is distorted and the FWHM values of the profile fluctuate as the source location changes. Anti-aliasing filters are required in this case to avoid the artifacts, but the timing is degraded as a result. When the sampling rate is marginally over the Nyquist rate, a proper signal interpolation is important. A sharp roll-off (higher order) filter is required to separate the baseband signal from its replicates to avoid the aliasing, but in return the computation will be higher. We demonstrated the analysis through a digital timing study using fast LSO scintillation crystals as used in time-of-flight PET scanners. From the study, we observed that there is no significant timing resolution degradation down to 1.3 Ghz sampling frequency, and the computation requirement for the signal interpolation is reasonably low. A so-called sliding test is proposed as a validation tool checking constant timing resolution behavior of a given timing pick-off method regardless of the source location change. Lastly, the performance comparison for several digital timing methods is also shown.

  19. Digital Simulation of a Hybrid Active Filter - An Active Filter in Series with a Shunt Passive Filter

    OpenAIRE

    Sitaram, Mahesh I; Padiyar, KR; Ramanarayanan, V

    1998-01-01

    Active filters have long been in use for the filtering of power system load harmonics. In this paper, the digital simulation results of a hybrid active power filter system for a rectifier load are presented. The active filter is used for filtering higher order harmonics as the dominant harmonics are filtered by the passive filter. This reduces the rating of the active filter significantly. The DC capacitor voltage of the active filter is controlled using a PI controller.

  20. An approach for fixed coefficient RNS-based FIR filter

    Science.gov (United States)

    Srinivasa Reddy, Kotha; Sahoo, Subhendu Kumar

    2017-08-01

    In this work, an efficient new modular multiplication method for {2k-1, 2k, 2k+1-1} moduli set is proposed to implement a residue number system (RNS)-based fixed coefficient finite impulse response filter. The new multiplication approach reduces the number of partial products by using pre-loaded product block. The reduction in partial products with the proposed modular multiplication improves the clock frequency and reduces the area and power as compared with the conventional modular multiplication. Further, the present approach eliminates a binary number to residue number converter circuit, which is usually needed at the front end of RNS-based system. In this work, two fixed coefficient filter architectures with the new modular multiplication approach are proposed. The filters are implemented using Verilog hardware description language. The United Microelectronics Corporation 90 nm technology library has been used for synthesis and the results area, power and delay are obtained with the help of Cadence register transfer level compiler. The power delay product (PDP) is also considered for performance comparison among the proposed filters. One of the proposed architecture is found to improve PDP gain by 60.83% as compared with the filter implemented with conventional modular multiplier. The filters functionality is validated with the help of Altera DSP Builder.

  1. Explosive Destruction System’s Drum Filter. Part 1. Experimental Validation

    Science.gov (United States)

    2011-06-01

    test to quantify filtration performance for MEA. Being a relatively low vapor pressure chemical, MEA is strongly adsorbed by microporous adsorbents...DMMP and the nerve/HD agents I I that it simulates are strongly adsorbed by microporous adsorbents, loading on the adsorbent is relatively...is started, the challenge chemical is fed to the top of the test filter located in an insulated enclosure (9), which can be seen immediately to the

  2. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    Science.gov (United States)

    Azim M., Osama A.

    2007-02-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a `real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A.

  3. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    International Nuclear Information System (INIS)

    Azim M, Osama A.

    2007-01-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a 'real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A

  4. Validation of a Modified Life-Space Assessment in Multimorbid Older Persons With Cognitive Impairment.

    Science.gov (United States)

    Ullrich, Phoebe; Werner, Christian; Bongartz, Martin; Kiss, Rainer; Bauer, Jürgen; Hauer, Klaus

    2018-01-31

    To investigate the validity, reliability, sensitivity to change, and feasibility of a modified University of Alabama at Birmingham Study of Aging Life-Space Assessment (UAB-LSA) in older persons with cognitive impairment (CI). The UAB-LSA was modified for use in persons with CI Life-Space Assessment for Persons with Cognitive Impairment (LSA-CI). Measurement properties of the LSA-CI were investigated using data of 118 multimorbid older participants with CI [mean age (SD): 82.3 (6.0) years, mean Mini-Mental State Examination score: 23.3 (2.4) points] from a randomized controlled trial (RCT) to improve motor performance and physical activity. Construct validity was asessed by Spearman's rank (rs) and point-biseral correlations (rpb) with age, gender, motor, and cognitive status, psychosocial factors, and sensor-derived (outdoor) physical activity variables. Test-retest reliability was analyzed using intra-class correlation coefficients (ICCs). Sensitivity to change was determined by standardized response means (SRMs) calculated for the RCT intervention group. The LSA-CI demonstrated moderate to high construct validity, with significant correlations of the LSA-CI scores with (outdoor) physical activity (rs = .23-.63), motor status (rs = .27-.56), fear of falling-related psychosocial variables (rs = |.24-.44|), and demographic characteristics (rpb = |.27-.32|). Test-retest reliability was good to excellent (ICC = .65-.91). Sensitivity to change was excellent for the LSA-CI composite score (SRM = .80) and small to moderate for the LSA-CI subscores (SRM = .35-.60). A completion rate of 100% and a mean completion time of 4.1 min) documented good feasibility. The LSA-CI represents a valid, reliable, sensitive, and feasible interview-based life-space assessment tool in multimorbid older persons with CI. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Design and full scale test of a sand bed filter

    International Nuclear Information System (INIS)

    Kaercher, M.

    1991-01-01

    All French pressurized water reactor plants are equipped with a containment venting system. this system is designed and implemented by Electricite de France with the technical support of safety authorities (Institute of Protection and Nuclear Safety of Atomic Energy Commission). This paper covers the following items: main assumptions, sizing and design requirements; basic design of the filter resulting from PITEAS R and D program carried out between 1983 and 1989 at Cadarache nuclear center; full scale tests performed in 1990 on FUCHIA loop at Cadarache including description of the loop using plasma torches to generate CsOH aerosols in a steam - air flow, and preliminary results concerning thermohydraulic and thermic behavior under residual power simulated filtration efficiency with CsOH aerosols and iodine; complementary design, including hydrogen risk during condensation period, radiological shieldings of the filter, and heat removal after the filter closure; and conclusion on the validation of the filter

  6. High-performance information search filters for acute kidney injury content in PubMed, Ovid Medline and Embase.

    Science.gov (United States)

    Hildebrand, Ainslie M; Iansavichus, Arthur V; Haynes, R Brian; Wilczynski, Nancy L; Mehta, Ravindra L; Parikh, Chirag R; Garg, Amit X

    2014-04-01

    We frequently fail to identify articles relevant to the subject of acute kidney injury (AKI) when searching the large bibliographic databases such as PubMed, Ovid Medline or Embase. To address this issue, we used computer automation to create information search filters to better identify articles relevant to AKI in these databases. We first manually reviewed a sample of 22 992 full-text articles and used prespecified criteria to determine whether each article contained AKI content or not. In the development phase (two-thirds of the sample), we developed and tested the performance of >1.3-million unique filters. Filters with high sensitivity and high specificity for the identification of AKI articles were then retested in the validation phase (remaining third of the sample). We succeeded in developing and validating high-performance AKI search filters for each bibliographic database with sensitivities and specificities in excess of 90%. Filters optimized for sensitivity reached at least 97.2% sensitivity, and filters optimized for specificity reached at least 99.5% specificity. The filters were complex; for example one PubMed filter included >140 terms used in combination, including 'acute kidney injury', 'tubular necrosis', 'azotemia' and 'ischemic injury'. In proof-of-concept searches, physicians found more articles relevant to topics in AKI with the use of the filters. PubMed, Ovid Medline and Embase can be filtered for articles relevant to AKI in a reliable manner. These high-performance information filters are now available online and can be used to better identify AKI content in large bibliographic databases.

  7. Filter assembly for metallic and intermetallic tube filters

    Science.gov (United States)

    Alvin, Mary Anne; Lippert, Thomas E.; Bruck, Gerald J.; Smeltzer, Eugene E.

    2001-01-01

    A filter assembly (60) for holding a filter element (28) within a hot gas cleanup system pressure vessel is provided, containing: a filter housing (62), said filter housing having a certain axial length and having a peripheral sidewall, said sidewall defining an interior chamber (66); a one piece, all metal, fail-safe/regenerator device (68) within the interior chamber (66) of the filter housing (62) and/or extending beyond the axial length of the filter housing, said device containing an outward extending radial flange (71) within the filter housing for seating an essential seal (70), the device also having heat transfer media (72) disposed inside and screens (80) for particulate removal; one compliant gasket (70) positioned next to and above the outward extending radial flange of the fail-safe/regenerator device; and a porous metallic corrosion resistant superalloy type filter element body welded at the bottom of the metal fail-safe/regenerator device.

  8. Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

    Directory of Open Access Journals (Sweden)

    Juan G. Gonzalez

    2002-01-01

    Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the α-stable and generalized-t. We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the “normal” equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

  9. Filter material charging apparatus for filter assembly for radioactive contaminants

    International Nuclear Information System (INIS)

    Goldsmith, J.M.; O'Nan, A. Jr.

    1977-01-01

    A filter charging apparatus for a filter assembly is described. The filter assembly includes a housing with at least one filter bed therein and the filter charging apparatus for adding filter material to the filter assembly includes a tank with an opening therein, the tank opening being disposed in flow communication with opposed first and second conduit means, the first conduit means being in flow communication with the filter assembly housing and the second conduit means being in flow communication with a blower means. Upon activation of the blower means, the blower means pneumatically conveys the filter material from the tank to the filter housing

  10. Independent control of replication initiation of the two Vibrio cholerae chromosomes by DnaA and RctB

    DEFF Research Database (Denmark)

    Duigou, Stephane; Knudsen, Kristine Groth; Skovgaard, Ole

    2006-01-01

    Although the two Vibrio cholerae chromosomes initiate replication in a coordinated fashion, we show here that each chromosome appears to have a specific replication initiator. DnaA overproduction promoted overinitiation of chromosome I and not chromosome II. In contrast, overproduction of RctB, a...

  11. Mechanisms of Günther Tulip filter tilting during transfemoral placement.

    Science.gov (United States)

    Matsui, Y; Horikawa, M; Ohta, K; Jahangiri Noudeh, Y; Kaufman, J A; Farsad, K

    The purpose of this study was to characterize the mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement in an experimental model with further validation in a clinical series. In an experimental study, 120 GTF placements in an inferior vena cava (IVC) model were performed using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to IVC wall prior to deployment were evaluated. The association of those pre-deployment factors with post-deployment filter tilting was analyzed. The association noted in the experimental study was then evaluated in a retrospective clinical series of 21 patients. In the experimental study, there was a significant association between the pre-deployment angle and post-deployment filter tilting (P<0.0001). With a low pre-deployment angle (≤5°), a significant association was noted between filter tilting and the proximity of the constrained filter legs to the far IVC wall (P=0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment filter tilting was also noted with a linear regression model (P=0.026). Significant association of the pre-deployment angle with post-deployment GTF tilting was shown in both the experimental and clinical studies. The experimental study also showed that proximity of filter legs is relevant when pre-deployment angle is small. Addressing these factors may result in a lower incidence of filter tilting. Copyright © 2017 Editions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  12. High Selectivity Dual-Band Bandpass Filter with Tunable Lower Passband

    Directory of Open Access Journals (Sweden)

    Wei-Qiang Pan

    2015-01-01

    Full Text Available This paper presents a novel method to design dual-band bandpass filters with tunable lower passband and fixed upper passband. It utilizes a trimode resonator with three controllable resonant modes. Discriminating coupling is used to suppress the unwanted mode to avoid the interference. Varactors are utilized to realize tunable responses. The bandwidth of the two bands can be controlled individually. Transmission zeros are generated near the passband edges, resulting in high selectivity. For demonstration, a tunable bandpass filter is implemented. Good agreement between the prediction and measurement validates the proposed method.

  13. A Divergence Median-based Geometric Detector with A Weighted Averaging Filter

    Science.gov (United States)

    Hua, Xiaoqiang; Cheng, Yongqiang; Li, Yubo; Wang, Hongqiang; Qin, Yuliang

    2018-01-01

    To overcome the performance degradation of the classical fast Fourier transform (FFT)-based constant false alarm rate detector with the limited sample data, a divergence median-based geometric detector on the Riemannian manifold of Heimitian positive definite matrices is proposed in this paper. In particular, an autocorrelation matrix is used to model the correlation of sample data. This method of the modeling can avoid the poor Doppler resolution as well as the energy spread of the Doppler filter banks result from the FFT. Moreover, a weighted averaging filter, conceived from the philosophy of the bilateral filtering in image denoising, is proposed and combined within the geometric detection framework. As the weighted averaging filter acts as the clutter suppression, the performance of the geometric detector is improved. Numerical experiments are given to validate the effectiveness of our proposed method.

  14. Robust extended Kalman filter of discrete-time Markovian jump nonlinear system under uncertain noise

    International Nuclear Information System (INIS)

    Zhu, Jin; Park, Jun Hong; Lee, Kwan Soo; Spiryagin, Maksym

    2008-01-01

    This paper examines the problem of robust extended Kalman filter design for discrete -time Markovian jump nonlinear systems with noise uncertainty. Because of the existence of stochastic Markovian switching, the state and measurement equations of underlying system are subject to uncertain noise whose covariance matrices are time-varying or un-measurable instead of stationary. First, based on the expression of filtering performance deviation, admissible uncertainty of noise covariance matrix is given. Secondly, two forms of noise uncertainty are taken into account: Non- Structural and Structural. It is proved by applying game theory that this filter design is a robust mini-max filter. A numerical example shows the validity of the method

  15. Stability analysis and active damping for LLCL-filter based grid-connected inverters

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A higher order passive power filter (LLCL-filter) for the grid-tied inverter is becoming attractive for the industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. To avoid the well-known stability problems of the LLCL-filter it is requested to use...... either passive or active damping methods. This paper analyzes the stability when damping is required and when damping is not necessary considering sampling and transport delay. Basic LLCL resonance damping properties of different feedback states are also studied. Then an active damping method which...... is using the capacitor current feedback for LLCL-filter is introduced. Based on this method, a design procedure for the control method is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  16. Stability Analysis and Active Damping for LLCL-filter-Based Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    to use either passive or active damping methods. This paper analyzes the stability of the LLCL-filter based grid-connected inverter and identifies a critical resonant frequency for the LLCL-filter when sampling and transport delays are considered. In a high resonant frequency region the active damping...... is not required but in a low resonant frequency region the active damping is necessary. The basic LLCL resonance damping properties of different feedback states based on a notch filter concept are also studied. Then an active damping method which is using the capacitor current feedback for LLCL......-filter is introduced. Based on this active damping method, a design procedure for the controller is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  17. Review of in-place HEPA filter testing at several DOE facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mokler, B.V.; Scripsick, R.C. [Los Alamos National Laboratory, NM (United States)

    1995-02-01

    The Office of Nuclear Energy Self-Assessment recently sponsored reviews of HEPA filter systems at several DOE facilities. One aspect emphasized in these reviews was in-place filter testing practices. Although in-place testing was generally performed as required in facility specifications, we noted several areas in which improvements were possible. Examples of some common problems and approaches to their solution will be presented. Areas of suggested improvement include: (1) ensuring the validity of test results; (2) recognizing and quantifying the uncertainty in penetration measurements; (3) expanding the analysis and reporting of test results to provide more than pass/fail information; (4) addressing the special problems of multiple stage systems; and (5) increasing the technical support and training provided in-place testing personnel. Ensuring the validity of test results, for example, requires more careful attention to the operation of test equipment, checking test measurements and system operating parameters for internal consistency, and more attention to documentation of system geometry and operation. Some issues will require additional study before the results can be incorporated into decision making on filter bank testing requirements and performance specifications.

  18. Review of in-place HEPA filter testing at several DOE facilities

    International Nuclear Information System (INIS)

    Mokler, B.V.; Scripsick, R.C.

    1995-01-01

    The Office of Nuclear Energy Self-Assessment recently sponsored reviews of HEPA filter systems at several DOE facilities. One aspect emphasized in these reviews was in-place filter testing practices. Although in-place testing was generally performed as required in facility specifications, we noted several areas in which improvements were possible. Examples of some common problems and approaches to their solution will be presented. Areas of suggested improvement include: (1) ensuring the validity of test results; (2) recognizing and quantifying the uncertainty in penetration measurements; (3) expanding the analysis and reporting of test results to provide more than pass/fail information; (4) addressing the special problems of multiple stage systems; and (5) increasing the technical support and training provided in-place testing personnel. Ensuring the validity of test results, for example, requires more careful attention to the operation of test equipment, checking test measurements and system operating parameters for internal consistency, and more attention to documentation of system geometry and operation. Some issues will require additional study before the results can be incorporated into decision making on filter bank testing requirements and performance specifications

  19. A New LCL -Filter With In-Series Parallel Resonant Circuit for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Sun, Yunjie; Lin, Zhe

    2014-01-01

    are investigated for the conventional LCL-filter-based system. Based on this, a modified LCL-filter topology using an extra parallel LrCr resonant circuit is proposed to reduce the total inductance value, without increasing the capacitive reactive power. The validity is verified through the experiments on a 500-W...

  20. Economical Implementation of a Filter Engine in an FPGA

    Science.gov (United States)

    Kowalski, James E.

    2009-01-01

    A logic design has been conceived for a field-programmable gate array (FPGA) that would implement a complex system of multiple digital state-space filters. The main innovative aspect of this design lies in providing for reuse of parts of the FPGA hardware to perform different parts of the filter computations at different times, in such a manner as to enable the timely performance of all required computations in the face of limitations on available FPGA hardware resources. The implementation of the digital state-space filter involves matrix vector multiplications, which, in the absence of the present innovation, would ordinarily necessitate some multiplexing of vector elements and/or routing of data flows along multiple paths. The design concept calls for implementing vector registers as shift registers to simplify operand access to multipliers and accumulators, obviating both multiplexing and routing of data along multiple paths. Each vector register would be reused for different parts of a calculation. Outputs would always be drawn from the same register, and inputs would always be loaded into the same register. A simple state machine would control each filter. The output of a given filter would be passed to the next filter, accompanied by a "valid" signal, which would start the state machine of the next filter. Multiple filter modules would share a multiplication/accumulation arithmetic unit. The filter computations would be timed by use of a clock having a frequency high enough, relative to the input and output data rate, to provide enough cycles for matrix and vector arithmetic operations. This design concept could prove beneficial in numerous applications in which digital filters are used and/or vectors are multiplied by coefficient matrices. Examples of such applications include general signal processing, filtering of signals in control systems, processing of geophysical measurements, and medical imaging. For these and other applications, it could be

  1. Bayesian learning for spatial filtering in an EEG-based brain-computer interface.

    Science.gov (United States)

    Zhang, Haihong; Yang, Huijuan; Guan, Cuntai

    2013-07-01

    Spatial filtering for EEG feature extraction and classification is an important tool in brain-computer interface. However, there is generally no established theory that links spatial filtering directly to Bayes classification error. To address this issue, this paper proposes and studies a Bayesian analysis theory for spatial filtering in relation to Bayes error. Following the maximum entropy principle, we introduce a gamma probability model for describing single-trial EEG power features. We then formulate and analyze the theoretical relationship between Bayes classification error and the so-called Rayleigh quotient, which is a function of spatial filters and basically measures the ratio in power features between two classes. This paper also reports our extensive study that examines the theory and its use in classification, using three publicly available EEG data sets and state-of-the-art spatial filtering techniques and various classifiers. Specifically, we validate the positive relationship between Bayes error and Rayleigh quotient in real EEG power features. Finally, we demonstrate that the Bayes error can be practically reduced by applying a new spatial filter with lower Rayleigh quotient.

  2. A filter-mediated communication model for design collaboration in building construction.

    Science.gov (United States)

    Lee, Jaewook; Jeong, Yongwook; Oh, Minho; Hong, Seung Wan

    2014-01-01

    Multidisciplinary collaboration is an important aspect of modern engineering activities, arising from the growing complexity of artifacts whose design and construction require knowledge and skills that exceed the capacities of any one professional. However, current collaboration in the architecture, engineering, and construction industries often fails due to lack of shared understanding between different participants and limitations of their supporting tools. To achieve a high level of shared understanding, this study proposes a filter-mediated communication model. In the proposed model, participants retain their own data in the form most appropriate for their needs with domain-specific filters that transform the neutral representations into semantically rich ones, as needed by the participants. Conversely, the filters can translate semantically rich, domain-specific data into a neutral representation that can be accessed by other domain-specific filters. To validate the feasibility of the proposed model, we computationally implement the filter mechanism and apply it to a hypothetical test case. The result acknowledges that the filter mechanism can let the participants know ahead of time what will be the implications of their proposed actions, as seen from other participants' points of view.

  3. Experimental study of filter cake formation on different filter media

    International Nuclear Information System (INIS)

    Saleem, M.

    2009-01-01

    Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

  4. Particle filtering with path sampling and an application to a bimodal ocean current model

    International Nuclear Information System (INIS)

    Weare, Jonathan

    2009-01-01

    This paper introduces a recursive particle filtering algorithm designed to filter high dimensional systems with complicated non-linear and non-Gaussian effects. The method incorporates a parallel marginalization (PMMC) step in conjunction with the hybrid Monte Carlo (HMC) scheme to improve samples generated by standard particle filters. Parallel marginalization is an efficient Markov chain Monte Carlo (MCMC) strategy that uses lower dimensional approximate marginal distributions of the target distribution to accelerate equilibration. As a validation the algorithm is tested on a 2516 dimensional, bimodal, stochastic model motivated by the Kuroshio current that runs along the Japanese coast. The results of this test indicate that the method is an attractive alternative for problems that require the generality of a particle filter but have been inaccessible due to the limitations of standard particle filtering strategies.

  5. MST Filterability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-12

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO2, and NaNO3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

  6. Super-resolution pupil filtering for visual performance enhancement using adaptive optics

    Science.gov (United States)

    Zhao, Lina; Dai, Yun; Zhao, Junlei; Zhou, Xiaojun

    2018-05-01

    Ocular aberration correction can significantly improve visual function of the human eye. However, even under ideal aberration correction conditions, pupil diffraction restricts the resolution of retinal images. Pupil filtering is a simple super-resolution (SR) method that can overcome this diffraction barrier. In this study, a 145-element piezoelectric deformable mirror was used as a pupil phase filter because of its programmability and high fitting accuracy. Continuous phase-only filters were designed based on Zernike polynomial series and fitted through closed-loop adaptive optics. SR results were validated using double-pass point spread function images. Contrast sensitivity was further assessed to verify the SR effect on visual function. An F-test was conducted for nested models to statistically compare different CSFs. These results indicated CSFs for the proposed SR filter were significantly higher than the diffraction correction (p vision optical correction of the human eye.

  7. Numerical and experimental study of pulse-jet cleaning in fabric filters

    DEFF Research Database (Denmark)

    O. Andersen, B.; Nielsen, N. F.; Walther, J. H.

    2016-01-01

    Pulse-jet cleaning and understanding of the complex physics are essential when designing fabric filters used for air pollution control. Today, low-pressure cleaning is of particular interest due to demand for reduced compressed air consumption. Pulse-jet cleaned fabric filters have been studied......-pressure fabric filters (2 bar) is studied using a full three-dimensional (3D) CFD model. Experimental results obtained in a pilot-scale test filter with 28 bags, in length of 10 m and in general full-scale dimensions of the cleaning system are used to verify the reliability of the present CFD model....... The validated CFD model reveals the strong compressible effects, a highly transient behaviour, the formation of compressible vortex rings and the shock cell phenomenon within the overexpanded supersonic jet. The cleaning nozzles and venturi design aid or oppose the pulse-pressure within the bags, and this plays...

  8. Maximum Correntropy Criterion Kalman Filter for α-Jerk Tracking Model with Non-Gaussian Noise

    Directory of Open Access Journals (Sweden)

    Bowen Hou

    2017-11-01

    Full Text Available As one of the most critical issues for target track, α -jerk model is an effective maneuver target track model. Non-Gaussian noises always exist in the track process, which usually lead to inconsistency and divergence of the track filter. A novel Kalman filter is derived and applied on α -jerk tracking model to handle non-Gaussian noise. The weighted least square solution is presented and the standard Kalman filter is deduced firstly. A novel Kalman filter with the weighted least square based on the maximum correntropy criterion is deduced. The robustness of the maximum correntropy criterion is also analyzed with the influence function and compared with the Huber-based filter, and, moreover, the kernel size of Gaussian kernel plays an important role in the filter algorithm. A new adaptive kernel method is proposed in this paper to adjust the parameter in real time. Finally, simulation results indicate the validity and the efficiency of the proposed filter. The comparison study shows that the proposed filter can significantly reduce the noise influence for α -jerk model.

  9. Scattering profiles of sparks and combustibility of filter against hot sparks

    International Nuclear Information System (INIS)

    Tobita, Noriyuki; Okada, Takashi; Kashiro, Kashio

    2004-12-01

    An event that a pre-filter burned on fire took place in the glove box dismantlement facility of Plutonium Production Facility, on April 21, 2003. The direct cause of this event was considered to be sparks generated by an abrasive wheel cutter, some of which reached the pre-filter and eventually burned the pre-filter. Further investigation revealed that there exist other deficiencies those of which formed indirect causes of the event, i.e., the wheel cutter was used without protective cover and adequate shield against sparks was not installed during the operation. To prevent similar event in the future, following corrective actions were introduced. Wheel cutter will not be used without protective cover; Incombustible pre-filter will be used; Shield will be place at the front of the pre-filter. We have conducted series of experimental tests in order to evaluate and confirm the validity of these corrective actions as well as determine the cause of the fire. This report present the results of these tests. (author)

  10. A vector Wiener filter for dual-radionuclide imaging

    International Nuclear Information System (INIS)

    Links, J.M.; Prince, J.L.; Gupta, S.N.

    1996-01-01

    The routine use of a single radionuclide for patient imaging in nuclear medicine can be complemented by studies employing two tracers to examine two different processes in a single organ, most frequently by simultaneous imaging of both radionuclides in two different energy windows. In addition, simultaneous transmission/emission imaging with dual-radionuclides has been described, with one radionuclide used for the transmission study and a second for the emission study. There is thus currently considerable interest in dual-radionuclide imaging. A major problem with all dual-radionuclide imaging is the crosstalk between the two radionuclides. Such crosstalk frequently occurs, because scattered radiation from the higher energy radionuclide is detected in the lower energy window, and because the lower energy radionuclide may have higher energy emissions which are detected in the higher energy window. The authors have previously described the use of Fourier-based restoration filtering in single photon emission computed tomography (SPECT) and positron emission tomography (PET) to improve quantitative accuracy by designing a Wiener or other Fourier filter to partially restore the loss of contrast due to scatter and finite spatial resolution effects. The authors describe here the derivation and initial validation of an extension of such filtering for dual-radionuclide imaging that simultaneously (1) improves contrast in each radionuclide's direct image, (2) reduces image noise, and (3) reduces the crosstalk contribution from the other radionuclide. This filter is based on a vector version of the Wiener filter, which is shown to be superior [in the minimum mean square error (MMSE) sense] to the sequential application of separate crosstalk and restoration filters

  11. Numerical study of canister filters with alternatives filter cap configurations

    Science.gov (United States)

    Mohammed, A. N.; Daud, A. R.; Abdullah, K.; Seri, S. M.; Razali, M. A.; Hushim, M. F.; Khalid, A.

    2017-09-01

    Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

  12. The development of search filters for adverse effects of surgical interventions in medline and Embase.

    Science.gov (United States)

    Golder, Su; Wright, Kath; Loke, Yoon Kong

    2018-03-31

    Search filter development for adverse effects has tended to focus on retrieving studies of drug interventions. However, a different approach is required for surgical interventions. To develop and validate search filters for medline and Embase for the adverse effects of surgical interventions. Systematic reviews of surgical interventions where the primary focus was to evaluate adverse effect(s) were sought. The included studies within these reviews were divided randomly into a development set, evaluation set and validation set. Using word frequency analysis we constructed a sensitivity maximising search strategy and this was tested in the evaluation and validation set. Three hundred and fifty eight papers were included from 19 surgical intervention reviews. Three hundred and fifty two papers were available on medline and 348 were available on Embase. Generic adverse effects search strategies in medline and Embase could achieve approximately 90% relative recall. Recall could be further improved with the addition of specific adverse effects terms to the search strategies. We have derived and validated a novel search filter that has reasonable performance for identifying adverse effects of surgical interventions in medline and Embase. However, we appreciate the limitations of our methods, and recommend further research on larger sample sizes and prospective systematic reviews. © 2018 The Authors Health Information and Libraries Journal published by John Wiley & Sons Ltd on behalf of Health Libraries Group.

  13. Kalman filtering techniques for reducing variance of digital speckle displacement measurement noise

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ Target dynamics are assumed to be known in measuring digital speckle displacement. Use is made of a simple measurement equation, where measurement noise represents the effect of disturbances introduced in measurement process. From these assumptions, Kalman filter can be designed to reduce variance of measurement noise. An optical and analysis system was set up, by which object motion with constant displacement and constant velocity is experimented with to verify validity of Kalman filtering techniques for reduction of measurement noise variance.

  14. Atmospheric Transmission Measurements Using IR Lasers, Fourier Transform Spectroscopy, and Gas-Filter Correlation Techniques

    National Research Council Canada - National Science Library

    Dowling, J

    1977-01-01

    ... and a gas filter correlation spectrometer. Results obtained from three concurrent experiments used to generate a data base appropriate to high resolution transmission model validation are displayed...

  15. IAE-adaptive Kalman filter for INS/GPS integrated navigation system

    Institute of Scientific and Technical Information of China (English)

    Bian Hongwei; Jin Zhihua; Tian Weifeng

    2006-01-01

    A marine INS/GPS adaptive navigation system is presented in this paper. GPS with two antenna providing vessel's altitude is selected as the auxiliary system fusing with INS to improve the performance of the hybrid system. The Kalman filter is the most frequently used algorithm in the integrated navigation system, which is capable of estimating INS errors online based on the measured errors between INS and GPS. The standard Kalman filter (SKF) assumes that the statistics of the noise on each sensor are given. As long as the noise distributions do not change, the Kalman filter will give the optimal estimation. However GPS receiver will be disturbed easily and thus temporally changing measurement noise will join into the outputs of GPS, which will lead to performance degradation of the Kalman filter. Many researchers introduce fuzzy logic control method into innovation-based adaptive estimation adaptive Kalman filtering (IAE-AKF) algorithm, and accordingly propose various adaptive Kalman filters. However how to design the fuzzy logic controller is a very complicated problem still without a convincing solution. A novel IAE-AKF is proposed herein, which is based on the maximum likelihood criterion for the proper computation of the filter innovation covariance and hence of the filter gain. The approach is direct and simple without having to establish fuzzy inference rules. After having deduced the proposed IAE-AKF algorithm theoretically in detail, the approach is tested by the simulation based on the system error model of the developed INS/GPS integrated marine navigation system. Simulation results show that the adaptive Kalman filter outperforms the SKF with higher accuracy, robustness and less computation. It is demonstrated that this proposed approach is a valid solution for the unknown changing measurement noise exited in the Kalman filter.

  16. WE-F-16A-02: Design, Fabrication, and Validation of a 3D-Printed Proton Filter for Range Spreading

    International Nuclear Information System (INIS)

    Remmes, N; Courneyea, L; Corner, S; Beltran, C; Kemp, B; Kruse, J; Herman, M; Stoker, J

    2014-01-01

    Purpose: To design, fabricate and test a 3D-printed filter for proton range spreading in scanned proton beams. The narrow Bragg peak in lower-energy synchrotron-based scanned proton beams can result in longer treatment times for shallow targets due to energy switching time and plan quality degradation due to minimum monitor unit limitations. A filter with variable thicknesses patterned on the same scale as the beam's lateral spot size will widen the Bragg peak. Methods: The filter consists of pyramids dimensioned to have a Gaussian distribution in thickness. The pyramids are 2.5mm wide at the base, 0.6 mm wide at the peak, 5mm tall, and are repeated in a 2.5mm pseudo-hexagonal lattice. Monte Carlo simulations of the filter in a proton beam were run using TOPAS to assess the change in depth profiles and lateral beam profiles. The prototypes were constrained to a 2.5cm diameter disk to allow for micro-CT imaging of promising prototypes. Three different 3D printers were tested. Depth-doses with and without the prototype filter were then measured in a ~70MeV proton beam using a multilayer ion chamber. Results: The simulation results were consistent with design expectations. Prototypes printed on one printer were clearly unacceptable on visual inspection. Prototypes on a second printer looked acceptable, but the micro-CT image showed unacceptable voids within the pyramids. Prototypes from the third printer appeared acceptable visually and on micro-CT imaging. Depth dose scans using the prototype from the third printer were consistent with simulation results. Bragg peak width increased by about 3x. Conclusions: A prototype 3D printer pyramid filter for range spreading was successfully designed, fabricated and tested. The filter has greater design flexibility and lower prototyping and production costs compared to traditional ridge filters. Printer and material selection played a large role in the successful development of the filter

  17. WE-F-16A-02: Design, Fabrication, and Validation of a 3D-Printed Proton Filter for Range Spreading

    Energy Technology Data Exchange (ETDEWEB)

    Remmes, N; Courneyea, L; Corner, S; Beltran, C; Kemp, B; Kruse, J; Herman, M [Mayo Clinic, Rochester, MN (United States); Stoker, J [MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To design, fabricate and test a 3D-printed filter for proton range spreading in scanned proton beams. The narrow Bragg peak in lower-energy synchrotron-based scanned proton beams can result in longer treatment times for shallow targets due to energy switching time and plan quality degradation due to minimum monitor unit limitations. A filter with variable thicknesses patterned on the same scale as the beam's lateral spot size will widen the Bragg peak. Methods: The filter consists of pyramids dimensioned to have a Gaussian distribution in thickness. The pyramids are 2.5mm wide at the base, 0.6 mm wide at the peak, 5mm tall, and are repeated in a 2.5mm pseudo-hexagonal lattice. Monte Carlo simulations of the filter in a proton beam were run using TOPAS to assess the change in depth profiles and lateral beam profiles. The prototypes were constrained to a 2.5cm diameter disk to allow for micro-CT imaging of promising prototypes. Three different 3D printers were tested. Depth-doses with and without the prototype filter were then measured in a ~70MeV proton beam using a multilayer ion chamber. Results: The simulation results were consistent with design expectations. Prototypes printed on one printer were clearly unacceptable on visual inspection. Prototypes on a second printer looked acceptable, but the micro-CT image showed unacceptable voids within the pyramids. Prototypes from the third printer appeared acceptable visually and on micro-CT imaging. Depth dose scans using the prototype from the third printer were consistent with simulation results. Bragg peak width increased by about 3x. Conclusions: A prototype 3D printer pyramid filter for range spreading was successfully designed, fabricated and tested. The filter has greater design flexibility and lower prototyping and production costs compared to traditional ridge filters. Printer and material selection played a large role in the successful development of the filter.

  18. Input-Admittance Passivity Compliance for Grid-Connected Converters with LCL Filter

    DEFF Research Database (Denmark)

    Diaz, Enrique Rodriguez; Freijedo, Francisco D.; Guerrero, Josep M.

    2018-01-01

    This work presents a design methodology and its experimental validation for the input-admittance passivity compliance of LCL grid-connected converters. The designs of the LCL filter parameters and discrete controller are addressed systematically, and suitable design guidelines are provided......-admittance passivity compliance....

  19. A novel strong tracking finite-difference extended Kalman filter for nonlinear eye tracking

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZuTao; ZHANG JiaShu

    2009-01-01

    Non-Intrusive methods for eye tracking are Important for many applications of vision-based human computer interaction. However, due to the high nonlinearity of eye motion, how to ensure the robust-ness of external interference and accuracy of eye tracking poses the primary obstacle to the integration of eye movements into today's interfaces. In this paper, we present a strong tracking finite-difference extended Kalman filter algorithm, aiming to overcome the difficulty In modeling nonlinear eye tracking. In filtering calculation, strong tracking factor is introduced to modify a priori covariance matrix and im-prove the accuracy of the filter. The filter uses finite-difference method to calculate partial derivatives of nonlinear functions for eye tracking. The latest experimental results show the validity of our method for eye tracking under realistic conditions.

  20. Design of a Narrow Bandwidth Bandpass Filter Using Compact Spiral Resonator with Chirality

    Directory of Open Access Journals (Sweden)

    Weiping Li

    2016-01-01

    Full Text Available In this article, a compact narrow-bandpass filter with high selectivity and improved rejection level is presented. For miniaturization, a pair of double negative (DNG cells consisting of quasi-planar chiral resonators are cascaded and electrically loaded to a microstrip transmission line; short ended stubs are introduced to expand upper rejection band. The structure is analyzed using equivalent circuit models and simulated based on EM simulation software. For validation, the proposed filter is fabricated and measured. The measured results are in good agreement with the simulated ones. By comparing to other filters in the references, it is shown that the proposed filter has the advantage of skirt selectivity and compact size, so it can be integrated more conveniently in modern wireless communication systems and microwave planar circuits.

  1. Controlling flow conditions of test filters in iodine filters

    International Nuclear Information System (INIS)

    Holmberg, R.; Laine, J.

    1979-03-01

    Several different iodine filter and test filter designs and experience gained from their operation are presented. For the flow experiments, an iodine filter system equipped with flow regulating and measuring devices was built. In the experiments the influence of the packing method of the iodine sorption material and the influence of the flow regulating and measuring divices upon the flow conditions in the test filters was studied. On the basis of the experiments it has been shown that the flows through the test filters always can be adjusted to a correct value if there only is a high enough pressure difference available across the test filter ducting. As a result of the research, several different methods are presented with which the flows through the test filters in both operating and future iodine sorption system can easily be measured and adjusted to their correct values. (author)

  2. The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

    Directory of Open Access Journals (Sweden)

    Karlsson Rickard

    2010-01-01

    Full Text Available For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF. This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

  3. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  4. CONSORT to community: translation of an RCT to a large-scale community intervention and learnings from evaluation of the upscaled program.

    Science.gov (United States)

    Moores, Carly Jane; Miller, Jacqueline; Perry, Rebecca Anne; Chan, Lily Lai Hang; Daniels, Lynne Allison; Vidgen, Helen Anna; Magarey, Anthea Margaret

    2017-11-29

    Translation encompasses the continuum from clinical efficacy to widespread adoption within the healthcare service and ultimately routine clinical practice. The Parenting, Eating and Activity for Child Health (PEACH™) program has previously demonstrated clinical effectiveness in the management of child obesity, and has been recently implemented as a large-scale community intervention in Queensland, Australia. This paper aims to describe the translation of the evaluation framework from a randomised controlled trial (RCT) to large-scale community intervention (PEACH™ QLD). Tensions between RCT paradigm and implementation research will be discussed along with lived evaluation challenges, responses to overcome these, and key learnings for future evaluation conducted at scale. The translation of evaluation from PEACH™ RCT to the large-scale community intervention PEACH™ QLD is described. While the CONSORT Statement was used to report findings from two previous RCTs, the REAIM framework was more suitable for the evaluation of upscaled delivery of the PEACH™ program. Evaluation of PEACH™ QLD was undertaken during the project delivery period from 2013 to 2016. Experiential learnings from conducting the evaluation of PEACH™ QLD to the described evaluation framework are presented for the purposes of informing the future evaluation of upscaled programs. Evaluation changes in response to real-time changes in the delivery of the PEACH™ QLD Project were necessary at stages during the project term. Key evaluation challenges encountered included the collection of complete evaluation data from a diverse and geographically dispersed workforce and the systematic collection of process evaluation data in real time to support program changes during the project. Evaluation of large-scale community interventions in the real world is challenging and divergent from RCTs which are rigourously evaluated within a more tightly-controlled clinical research setting. Constructs

  5. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  6. Performance Analysis of Local Ensemble Kalman Filter

    Science.gov (United States)

    Tong, Xin T.

    2018-03-01

    Ensemble Kalman filter (EnKF) is an important data assimilation method for high-dimensional geophysical systems. Efficient implementation of EnKF in practice often involves the localization technique, which updates each component using only information within a local radius. This paper rigorously analyzes the local EnKF (LEnKF) for linear systems and shows that the filter error can be dominated by the ensemble covariance, as long as (1) the sample size exceeds the logarithmic of state dimension and a constant that depends only on the local radius; (2) the forecast covariance matrix admits a stable localized structure. In particular, this indicates that with small system and observation noises, the filter error will be accurate in long time even if the initialization is not. The analysis also reveals an intrinsic inconsistency caused by the localization technique, and a stable localized structure is necessary to control this inconsistency. While this structure is usually taken for granted for the operation of LEnKF, it can also be rigorously proved for linear systems with sparse local observations and weak local interactions. These theoretical results are also validated by numerical implementation of LEnKF on a simple stochastic turbulence in two dynamical regimes.

  7. Gravity Matching Aided Inertial Navigation Technique Based on Marginal Robust Unscented Kalman Filter

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2015-01-01

    Full Text Available This paper is concerned with the topic of gravity matching aided inertial navigation technology using Kalman filter. The dynamic state space model for Kalman filter is constructed as follows: the error equation of the inertial navigation system is employed as the process equation while the local gravity model based on 9-point surface interpolation is employed as the observation equation. The unscented Kalman filter is employed to address the nonlinearity of the observation equation. The filter is refined in two ways as follows. The marginalization technique is employed to explore the conditionally linear substructure to reduce the computational load; specifically, the number of the needed sigma points is reduced from 15 to 5 after this technique is used. A robust technique based on Chi-square test is employed to make the filter insensitive to the uncertainties in the above constructed observation model. Numerical simulation is carried out, and the efficacy of the proposed method is validated by the simulation results.

  8. Compact and Wide Stopband Lowpass Filter Using Open Complementary Split Ring Resonator and Defected Ground Structure

    Directory of Open Access Journals (Sweden)

    S. S. Karthikeyan

    2015-09-01

    Full Text Available A compact (0.16 λg x 0.08 λg and wide stop¬band lowpass filter design using open complementary split ring resonator (OCSRR and defected ground structure (DGS is presented in this paper. Low pass filter is con-structed using two cascaded stages of OCSRR. Since the rejection bandwidth of the OCSRR is narrow, tapered dumbbell shaped DGS section is placed under the OCSRR to enhance the bandwidth. The cutoff frequency (fc of the proposed lowpass filter is 1.09 GHz. The rejection band¬width of the filter covers the entire ultra wideband spec¬trum. Hence the spurious passband suppression is achieved up to 10 fc. The designed filter has been fabri¬cated and validated by experimental results

  9. PIV Data Validation Software Package

    Science.gov (United States)

    Blackshire, James L.

    1997-01-01

    A PIV data validation and post-processing software package was developed to provide semi-automated data validation and data reduction capabilities for Particle Image Velocimetry data sets. The software provides three primary capabilities including (1) removal of spurious vector data, (2) filtering, smoothing, and interpolating of PIV data, and (3) calculations of out-of-plane vorticity, ensemble statistics, and turbulence statistics information. The software runs on an IBM PC/AT host computer working either under Microsoft Windows 3.1 or Windows 95 operating systems.

  10. A Study of Parallel Operation of an active Filter and passive Filters

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

    2002-01-01

    This paper reports investigations of the parallel operations of a current controlled active filter and passive filters in a system with current harmonic sources. The task of reactive power and harmonic compensation is shared by the active filter and passive filters. The passive filters are used...... arrangements of the active and passive filters can operate relatively independently, also the compensation flexibility of the active filter can be fully exploited, such as one active filter for several harmonic sources.The simulation studies on various systems have been performed to evaluate the effectiveness...... of the systems. The results show that the power factor is corrected by the passive filters, harmonics are minimized by both active and passive filters and overloading of the filter system can be avoided....

  11. Current Harmonics Cancellation in Three-Phase Four-Wire Systems by Using a Four-Branch Star Filtering Topology

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Candela, J. I.; Luna, A.

    2009-01-01

    This paper presents a new solution for filtering current harmonics in three-phase four-wire networks. The original four-branch star (FBS) filter topology presented in this paper is characterized by a particular layout of single-phase inductances and capacitors, without using any transformer......, a specific implementation of a three-phase four-wire hybrid power filter is presented as an illustrative application of the filtering topology. An extensive evaluation using simulation and experimental results from a DSP-based laboratory prototype is conducted in order to verify and validate the good...... only passive components are employed, or as a hybrid filter, when its behavior is improved by integrating a power converter into the filter structure. The paper analyzes the proposed topology, and derives fundamental concepts about the control of the resulting hybrid power filter. From this analysis...

  12. Successful Reach and Adoption of a workplace health promotion RCT targeting a group of high-risk workers

    Directory of Open Access Journals (Sweden)

    Ekner Dorte

    2010-06-01

    Full Text Available Abstract Background Cleaners are rarely introduced to workplace health promotion programs. The study's objective was to evaluate the reach and adoption of a workplace randomized controlled trial (RCT among cleaners in Denmark. Methods Cleaning businesses with at least 30 employees, that could offer a weekly 1-hour intervention during working hours, were invited to participate. Employees working at least 20 hours/week were invited to answer a screening questionnaire and consent to participate. Analyses determined the differences in health variables between responders and non-responders, consenters and non-consenters, participants and non-participants and between participants of the RCT's three groups: physical coordination training, cognitive-behavioural theory-based training and reference group. Results From 16 eligible workplaces, a representative sample of 50% adopted the trial. Of 758 eligible employees, 78% responded to the screening questionnaire and 49% consented to participate. Consenters and participants differed from non-consenters and non-participants by having higher BMI, more chronic diseases and poorer musculoskeletal health. Conclusions This study indicates that workplace health promotion programs directed at health risk factors among cleaners enable significant adoption and reach to a high-risk subgroup of the Danish workforce. Trial registration Trial registration ISRCTN96241850

  13. Passive Power Filters

    CERN Document Server

    Künzi, R.

    2015-06-15

    Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

  14. Group hypnotherapy versus group relaxation for smoking cessation: an RCT study protocol.

    Science.gov (United States)

    Dickson-Spillmann, Maria; Kraemer, Thomas; Rust, Kristina; Schaub, Michael

    2012-04-04

    A significant number of smokers would like to stop smoking. Despite the demonstrated efficacy of pharmacological smoking cessation treatments, many smokers are unwilling to use them; however, they are inclined to try alternative methods. Hypnosis has a long-standing reputation in smoking cessation therapy, but its efficacy has not been scientifically proven. We designed this randomised controlled trial to evaluate the effects of group hypnosis as a method for smoking cessation, and we will compare the results of group hypnosis with group relaxation. This is a randomised controlled trial (RCT) to compare the efficacy of a single session of hypnosis with that of relaxation performed in groups of 8-15 smokers. We intend to include at least 220 participants in our trial. The inclusion criteria include smoking at least 5 cigarettes per day, not using other cessation methods and being willing to quit smoking. The intervention is performed by a trained hypnotist/relaxation therapist. Both groups first receive 40 min of mental preparation that is based on motivational interviewing. Then, a state of deep relaxation is induced in the hypnosis condition, and superficial relaxation is induced in the control condition. Suggestions are made in the hypnosis condition that aim to switch the mental self-image of the participants from that of smokers to that of non-smokers. Each intervention lasts for 40 min. The participants also complete questionnaires that assess their smoking status and symptoms of depression and anxiety at baseline, 2 weeks and 6 months post-intervention. In addition, saliva samples are collected to assess cotinine levels at baseline and at 6 months post-intervention. We also assess nicotine withdrawal symptoms at 2 weeks post-intervention. To the best of our knowledge, this RCT is the first to test the efficacy of group hypnosis versus group relaxation. Issues requiring discussion in the outcome paper include the lack of standardisation of hypnotic

  15. Research on Kalman Filtering Algorithm for Deformation Information Series of Similar Single-Difference Model

    Institute of Scientific and Technical Information of China (English)

    L(U) Wei-cai; XU Shao-quan

    2004-01-01

    Using similar single-difference methodology(SSDM) to solve the deformation values of the monitoring points, there is unstability of the deformation information series, at sometimes.In order to overcome this shortcoming, Kalman filtering algorithm for this series is established,and its correctness and validity are verified with the test data obtained on the movable platform in plane. The results show that Kalman filtering can improve the correctness, reliability and stability of the deformation information series.

  16. RB Particle Filter Time Synchronization Algorithm Based on the DPM Model.

    Science.gov (United States)

    Guo, Chunsheng; Shen, Jia; Sun, Yao; Ying, Na

    2015-09-03

    Time synchronization is essential for node localization, target tracking, data fusion, and various other Wireless Sensor Network (WSN) applications. To improve the estimation accuracy of continuous clock offset and skew of mobile nodes in WSNs, we propose a novel time synchronization algorithm, the Rao-Blackwellised (RB) particle filter time synchronization algorithm based on the Dirichlet process mixture (DPM) model. In a state-space equation with a linear substructure, state variables are divided into linear and non-linear variables by the RB particle filter algorithm. These two variables can be estimated using Kalman filter and particle filter, respectively, which improves the computational efficiency more so than if only the particle filter was used. In addition, the DPM model is used to describe the distribution of non-deterministic delays and to automatically adjust the number of Gaussian mixture model components based on the observational data. This improves the estimation accuracy of clock offset and skew, which allows achieving the time synchronization. The time synchronization performance of this algorithm is also validated by computer simulations and experimental measurements. The results show that the proposed algorithm has a higher time synchronization precision than traditional time synchronization algorithms.

  17. Particle Kalman Filtering: A Nonlinear Bayesian Framework for Ensemble Kalman Filters*

    KAUST Repository

    Hoteit, Ibrahim

    2012-02-01

    This paper investigates an approximation scheme of the optimal nonlinear Bayesian filter based on the Gaussian mixture representation of the state probability distribution function. The resulting filter is similar to the particle filter, but is different from it in that the standard weight-type correction in the particle filter is complemented by the Kalman-type correction with the associated covariance matrices in the Gaussian mixture. The authors show that this filter is an algorithm in between the Kalman filter and the particle filter, and therefore is referred to as the particle Kalman filter (PKF). In the PKF, the solution of a nonlinear filtering problem is expressed as the weighted average of an “ensemble of Kalman filters” operating in parallel. Running an ensemble of Kalman filters is, however, computationally prohibitive for realistic atmospheric and oceanic data assimilation problems. For this reason, the authors consider the construction of the PKF through an “ensemble” of ensemble Kalman filters (EnKFs) instead, and call the implementation the particle EnKF (PEnKF). It is shown that different types of the EnKFs can be considered as special cases of the PEnKF. Similar to the situation in the particle filter, the authors also introduce a resampling step to the PEnKF in order to reduce the risk of weights collapse and improve the performance of the filter. Numerical experiments with the strongly nonlinear Lorenz-96 model are presented and discussed.

  18. Rectifier Filters

    Directory of Open Access Journals (Sweden)

    Y. A. Bladyko

    2010-01-01

    Full Text Available The paper contains definition of a smoothing factor which is suitable for any rectifier filter. The formulae of complex smoothing factors have been developed for simple and complex passive filters. The paper shows conditions for application of calculation formulae and filters

  19. Retina-Inspired Filter.

    Science.gov (United States)

    Doutsi, Effrosyni; Fillatre, Lionel; Antonini, Marc; Gaulmin, Julien

    2018-07-01

    This paper introduces a novel filter, which is inspired by the human retina. The human retina consists of three different layers: the Outer Plexiform Layer (OPL), the inner plexiform layer, and the ganglionic layer. Our inspiration is the linear transform which takes place in the OPL and has been mathematically described by the neuroscientific model "virtual retina." This model is the cornerstone to derive the non-separable spatio-temporal OPL retina-inspired filter, briefly renamed retina-inspired filter, studied in this paper. This filter is connected to the dynamic behavior of the retina, which enables the retina to increase the sharpness of the visual stimulus during filtering before its transmission to the brain. We establish that this retina-inspired transform forms a group of spatio-temporal Weighted Difference of Gaussian (WDoG) filters when it is applied to a still image visible for a given time. We analyze the spatial frequency bandwidth of the retina-inspired filter with respect to time. It is shown that the WDoG spectrum varies from a lowpass filter to a bandpass filter. Therefore, while time increases, the retina-inspired filter enables to extract different kinds of information from the input image. Finally, we discuss the benefits of using the retina-inspired filter in image processing applications such as edge detection and compression.

  20. Spectral shaping of an all-fiber torsional acousto-optic tunable filter.

    Science.gov (United States)

    Ko, Jeakwon; Lee, Kwang Jo; Kim, Byoung Yoon

    2014-12-20

    Spectral shaping of an all-fiber torsional acousto-optic (AO) tunable filter is studied. The technique is based on the axial modulation of AO coupling strength along a highly birefringent optical fiber, which is achieved by tailoring the outer diameter of the fiber along its propagation axis. Two kinds of filter spectral shaping schemes-Gaussian apodization and matched filtering with triple resonance peaks-are proposed and numerically investigated under realistic experimental conditions: at the 50-cm-long AO interaction length of the fiber and at half of the original fiber diameter as the minimum thickness of the tailored fiber section. The results show that the highest peak of sidelobe spectra in filter transmission is suppressed from 11.64% to 0.54% via Gaussian modulation of the AO coupling coefficient (κ). Matched filtering with triple resonance peaks operating with a single radio frequency signal is also achieved by cosine modulation of κ, of which the modulation period determines the spectral distance between two satellite peaks located in both wings of the main resonance peak. The splitting of two satellite peaks in the filter spectra reaches 48.2 nm while the modulation period varies from 7.7 to 50 cm. The overall peak power of two satellite resonances is calculated to be 22% of the main resonance power. The results confirm the validity and practicality of our approach, and we predict robust and stable operation of the designed all-fiber torsional AO filters.

  1. Kalman Filter for Estimation of Sensor Acceleration Using Six - axis Inertial Sensor

    International Nuclear Information System (INIS)

    Lee, Jung Keun

    2015-01-01

    Although an accelerometer is a sensor that measures acceleration, it cannot be used by itself to measure the acceleration when the orientation of the sensor changes. This paper introduces a Kalman filter for the estimation of a sensor acceleration based on a six-axis inertial sensor (i.e., a three-axis accelerometer and three-axis gyroscope). The novelty of the proposed Kalman filter lies in the fact that its state vector includes not only the tilt angle variable but also the sensor acceleration. Thus, the filter can explicitly estimate the latter with a high accuracy. The accuracy of acceleration estimates were validated experimentally under three different dynamic conditions, using an optical motion capture system. It could be concluded that the performance of the proposed Kalman filter was comparable to that of the state-of-the-art estimation algorithm employed by the Xsens MTw. The proposed algorithm may be more suitable than inertial/magnetic sensor-based algorithms for various applications adopting six-axis inertial sensors

  2. Braile vena cava filter and greenfield filter in terms of centralization.

    Science.gov (United States)

    de Godoy, José Maria Pereira; Menezes da Silva, Adinaldo A; Reis, Luis Fernando; Miquelin, Daniel; Torati, José Luis Simon

    2013-01-01

    The aim of this study was to evaluate complications experienced during implantation of the Braile Vena Cava filter (VCF) and the efficacy of the centralization mechanism of the filter. This retrospective cohort study evaluated all Braile Biomédica VCFs implanted from 2004 to 2009 in Hospital de Base Medicine School in São José do Rio Preto, Brazil. Of particular concern was the filter's symmetry during implantation and complications experienced during the procedure. All the angiographic examinations performed during the implantation of the filters were analyzed in respect to the following parameters: migration of the filter, non-opening or difficulties in the implantation and centralization of the filter. A total of 112 Braile CVFs were implanted and there were no reports of filter opening difficulties or in respect to migration. Asymmetry was observed in 1/112 (0.9%) cases. A statistically significant difference was seen on comparing historical data on decentralization of the Greenfield filter with the data of this study. The Braile Biomédico filter is an evolution of the Greenfield filter providing improved embolus capture and better implantation symmetry.

  3. Comparison of filtering methods for the modeling and retrospective forecasting of influenza epidemics.

    Directory of Open Access Journals (Sweden)

    Wan Yang

    2014-04-01

    Full Text Available A variety of filtering methods enable the recursive estimation of system state variables and inference of model parameters. These methods have found application in a range of disciplines and settings, including engineering design and forecasting, and, over the last two decades, have been applied to infectious disease epidemiology. For any system of interest, the ideal filter depends on the nonlinearity and complexity of the model to which it is applied, the quality and abundance of observations being entrained, and the ultimate application (e.g. forecast, parameter estimation, etc.. Here, we compare the performance of six state-of-the-art filter methods when used to model and forecast influenza activity. Three particle filters--a basic particle filter (PF with resampling and regularization, maximum likelihood estimation via iterated filtering (MIF, and particle Markov chain Monte Carlo (pMCMC--and three ensemble filters--the ensemble Kalman filter (EnKF, the ensemble adjustment Kalman filter (EAKF, and the rank histogram filter (RHF--were used in conjunction with a humidity-forced susceptible-infectious-recovered-susceptible (SIRS model and weekly estimates of influenza incidence. The modeling frameworks, first validated with synthetic influenza epidemic data, were then applied to fit and retrospectively forecast the historical incidence time series of seven influenza epidemics during 2003-2012, for 115 cities in the United States. Results suggest that when using the SIRS model the ensemble filters and the basic PF are more capable of faithfully recreating historical influenza incidence time series, while the MIF and pMCMC do not perform as well for multimodal outbreaks. For forecast of the week with the highest influenza activity, the accuracies of the six model-filter frameworks are comparable; the three particle filters perform slightly better predicting peaks 1-5 weeks in the future; the ensemble filters are more accurate predicting peaks in

  4. Filtering data from the collaborative initial glaucoma treatment study for improved identification of glaucoma progression.

    Science.gov (United States)

    Schell, Greggory J; Lavieri, Mariel S; Stein, Joshua D; Musch, David C

    2013-12-21

    Open-angle glaucoma (OAG) is a prevalent, degenerate ocular disease which can lead to blindness without proper clinical management. The tests used to assess disease progression are susceptible to process and measurement noise. The aim of this study was to develop a methodology which accounts for the inherent noise in the data and improve significant disease progression identification. Longitudinal observations from the Collaborative Initial Glaucoma Treatment Study (CIGTS) were used to parameterize and validate a Kalman filter model and logistic regression function. The Kalman filter estimates the true value of biomarkers associated with OAG and forecasts future values of these variables. We develop two logistic regression models via generalized estimating equations (GEE) for calculating the probability of experiencing significant OAG progression: one model based on the raw measurements from CIGTS and another model based on the Kalman filter estimates of the CIGTS data. Receiver operating characteristic (ROC) curves and associated area under the ROC curve (AUC) estimates are calculated using cross-fold validation. The logistic regression model developed using Kalman filter estimates as data input achieves higher sensitivity and specificity than the model developed using raw measurements. The mean AUC for the Kalman filter-based model is 0.961 while the mean AUC for the raw measurements model is 0.889. Hence, using the probability function generated via Kalman filter estimates and GEE for logistic regression, we are able to more accurately classify patients and instances as experiencing significant OAG progression. A Kalman filter approach for estimating the true value of OAG biomarkers resulted in data input which improved the accuracy of a logistic regression classification model compared to a model using raw measurements as input. This methodology accounts for process and measurement noise to enable improved discrimination between progression and nonprogression

  5. Modelling and validation of a simple and compact wide upper stop band ultra-wideband bandpass filter

    Directory of Open Access Journals (Sweden)

    Somdotta Roy Choudhury

    2014-09-01

    Full Text Available A compact ultra-wideband (UWB bandpass filter (BPF is proposed based on end coupled microstrip transmission line, defected ground structure and defected microstrip structure. The experimental filter shows a fractional bandwidth of 110% at a centre frequency, with two observable transmission zeros (attenuation poles at 2.1 and 11.7 GHz. Measured results exhibit an UWB passband from 3.02 to 10.6 GHz with mid-band insertion loss of 1.8 dB and group delay variation <0.45 ns. The BPF achieves a wide stopband with < −18 dB attenuation up to 20 GHz.

  6. The social play, social skills and parent-child relationships of children with ADHD 12 months following a RCT of a play-based intervention.

    Science.gov (United States)

    Barnes, Gabrielle; Wilkes-Gillan, Sarah; Bundy, Anita; Cordier, Reinie

    2017-12-01

    There is an urgent need to investigate the long-term impact of social skill interventions for children with attention deficit hyperactivity disorder (ADHD). Interventions targeting the social skills of children with ADHD have limited short-term effectiveness and rarely investigate the long-term impact. Furthermore, these interventions are most frequently conducted in the clinic setting, without including the child's natural settings and interactants, such as their regular playmates and parents. The present study investigated the social play, social skills and parent-child relationships of children with ADHD and their playmates (n = 13/group) aged 5-13 years. A two-group before and after design with a longitudinal component was applied. Participant data compared over two time points, immediately following a randomised, controlled trial (RCT) of a play-based intervention and 12 months post-RCT. From immediately following the RCT to the 12-month follow-up, children with ADHD maintained social play skill gains in the home environment. Playmates maintained social play skill gains across the home and clinic environments. Children scored within a developmentally appropriate range, falling within 1 standard deviation of the mean for social skills and most parent-child relationship scales using norm-based assessments. Results support the long-term effectiveness of the intervention. © 2017 Occupational Therapy Australia.

  7. Outcomes and lessons from a pilot RCT of a community-based HIV prevention multi-session group intervention for gay men.

    Science.gov (United States)

    Harding, R; Bensley, J; Corrigan, N; Franks, L; Stratman, J; Waller, Z; Warner, J

    2004-07-01

    This paper presents the first outcome evaluation of multi-session groupwork for HIV prevention among gay men in the UK. This community-based RCT recruited 50 men, of whom 42% were HIV-positive or untested, and 32% reported status unknown or serodiscordant UAI in the previous 12 months. No knowledge, skills, attitudinal or behavioural differences were detected between intervention and control at baseline. At eight weeks, those attending the group reported significant gains over their control in making sexual choices, physical safety, HIV and STI transmission knowledge, and sexual negotiation skills. At 20 weeks, significant differences remained for HIV and STI transmission knowledge and comfort with sexual choices. Although no behavioural differences were detected, the aims of the National Prevention Strategy were met. This pilot RCT is appraised in the light of modest sample size and attrition, and recommendations for establishing behavioural outcomes are presented. This study has demonstrated that high-risk community samples can be recruited to multi-session interventions, and has provided feasibility data for future rigorous evaluation designs.

  8. Balanced microwave filters

    CERN Document Server

    Hong, Jiasheng; Medina, Francisco; Martiacuten, Ferran

    2018-01-01

    This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 exa...

  9. Backflushable filter insert

    International Nuclear Information System (INIS)

    Keith, R.C.; Vandenberg, T.; Randolph, M.C.; Lewis, T.B.; Gillis, P.J. Jr.

    1988-01-01

    Filter elements are mounted on a tube plate beneath an accumulator chamber whose wall is extended by skirt and flange to form a closure for the top of pressure vessel. The accumulator chamber is annular around a central pipe which serves as the outlet for filtered water passing from the filter elements. The chamber contains filtered compressed air from supply. Periodically the filtration of water is stopped and vessel is drained. Then a valve is opened, allowing the accumulated air to flow from chamber up a pipe and down pipe, pushing the filtered water from pipe back through the filter elements to clean them. The accumulator chamber is so proportioned, relative to the volume of the system communicating therewith during backflushing, that the equilibrium pressure during backflushing cannot exceed the pressure rating of the vessel. However a line monitors the pressure at the top of the vessel, and if it rises too far a bleed valve is automatically opened to depressurise the system. The chamber is intended to replace the lid of an existing vessel to convert a filter using filter aid to one using permanent filter elements. (author)

  10. Filter replacement lifetime prediction

    Science.gov (United States)

    Hamann, Hendrik F.; Klein, Levente I.; Manzer, Dennis G.; Marianno, Fernando J.

    2017-10-25

    Methods and systems for predicting a filter lifetime include building a filter effectiveness history based on contaminant sensor information associated with a filter; determining a rate of filter consumption with a processor based on the filter effectiveness history; and determining a remaining filter lifetime based on the determined rate of filter consumption. Methods and systems for increasing filter economy include measuring contaminants in an internal and an external environment; determining a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling; determining a cost of increased air pressure to filter external air; and if the cost of filtering external air exceeds the cost of the corrosion rate increase, increasing an intake of unfiltered external air.

  11. Anti-clogging filter system

    Science.gov (United States)

    Brown, Erik P.

    2015-05-19

    An anti-clogging filter system for filtering a fluid containing large particles and small particles includes an enclosure with at least one individual elongated tubular filter element in the enclosure. The individual elongated tubular filter element has an internal passage, a closed end, an open end, and a filtering material in or on the individual elongated tubular filter element. The fluid travels through the open end of the elongated tubular element and through the internal passage and through the filtering material. An anti-clogging element is positioned on or adjacent the individual elongated tubular filter element and provides a fluid curtain that preferentially directs the larger particulates to one area of the filter material allowing the remainder of the filter material to remain more efficient.

  12. Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Montejo-Garai, Jose R., E-mail: jr@etc.upm.es [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Leal-Sevillano, Carlos A. [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Ruiz-Cruz, Jorge A. [Escuela Politecnica Superior, Universidad Autonoma de Madrid, C/Fco. Tomas y Valiente 11, Madrid 28409 (Spain); Rebollar, Jesus M. [Departamento de Electromagnetismo y Teoria de Circuitos, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, Madrid 20840 (Spain); Estrada, Teresa [T. Laboratorio Nacional de Fusion, Asociacion Euratom-CIEMAT, Madrid 28040 (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer A rigorous systematic design process based on circuit synthesis is proposed for band-stop filters. Black-Right-Pointing-Pointer The new compact E-plane waveguide structure reduces drastically the unwanted resonances in a very large pass band. Black-Right-Pointing-Pointer The manufacturing process together with the computation effort is significantly reduced. Black-Right-Pointing-Pointer Experimental results validate the state-of-art electrical responses. - Abstract: Band-stop or notch filters play a crucial role in plasma diagnosis systems to protect receivers from the stray radiation. In this work, a rigorous design process based on circuit synthesis in addition to an extremely compact E-plane waveguide structure is proposed for this kind of filters. On the one hand, the transfer function verifying the rejection specification is analytically obtained, fixing the minimum number of required cavities. On the other hand, a coupling structure that reduces drastically the unwanted resonances in filters with a very large pass band requirement, is presented. This coupling between the rejection cavities and the main rectangular waveguide has additional advantages; (a) unlike typical inductive irises, large coupling coefficients can be implemented (b) a pure E-plane configuration is achieved, which simplifies the manufacturing and also reduces significantly the computational effort. Experimental validation is demonstrated by two pseudo-elliptic fifth-order band-stop filters fabricated and measured in Ka and V bands. In both cases, the filters are free of spurious resonances in their total operation bands.

  13. Synthesis and design of waveguide band-stop filters without out-of-band spurious responses for plasma diagnosis

    International Nuclear Information System (INIS)

    Montejo-Garai, José R.; Leal-Sevillano, Carlos A.; Ruiz-Cruz, Jorge A.; Rebollar, Jesús M.; Estrada, Teresa

    2012-01-01

    Highlights: ► A rigorous systematic design process based on circuit synthesis is proposed for band-stop filters. ► The new compact E-plane waveguide structure reduces drastically the unwanted resonances in a very large pass band. ► The manufacturing process together with the computation effort is significantly reduced. ► Experimental results validate the state-of-art electrical responses. - Abstract: Band-stop or notch filters play a crucial role in plasma diagnosis systems to protect receivers from the stray radiation. In this work, a rigorous design process based on circuit synthesis in addition to an extremely compact E-plane waveguide structure is proposed for this kind of filters. On the one hand, the transfer function verifying the rejection specification is analytically obtained, fixing the minimum number of required cavities. On the other hand, a coupling structure that reduces drastically the unwanted resonances in filters with a very large pass band requirement, is presented. This coupling between the rejection cavities and the main rectangular waveguide has additional advantages; (a) unlike typical inductive irises, large coupling coefficients can be implemented (b) a pure E-plane configuration is achieved, which simplifies the manufacturing and also reduces significantly the computational effort. Experimental validation is demonstrated by two pseudo-elliptic fifth-order band-stop filters fabricated and measured in Ka and V bands. In both cases, the filters are free of spurious resonances in their total operation bands.

  14. Selection vector filter framework

    Science.gov (United States)

    Lukac, Rastislav; Plataniotis, Konstantinos N.; Smolka, Bogdan; Venetsanopoulos, Anastasios N.

    2003-10-01

    We provide a unified framework of nonlinear vector techniques outputting the lowest ranked vector. The proposed framework constitutes a generalized filter class for multichannel signal processing. A new class of nonlinear selection filters are based on the robust order-statistic theory and the minimization of the weighted distance function to other input samples. The proposed method can be designed to perform a variety of filtering operations including previously developed filtering techniques such as vector median, basic vector directional filter, directional distance filter, weighted vector median filters and weighted directional filters. A wide range of filtering operations is guaranteed by the filter structure with two independent weight vectors for angular and distance domains of the vector space. In order to adapt the filter parameters to varying signal and noise statistics, we provide also the generalized optimization algorithms taking the advantage of the weighted median filters and the relationship between standard median filter and vector median filter. Thus, we can deal with both statistical and deterministic aspects of the filter design process. It will be shown that the proposed method holds the required properties such as the capability of modelling the underlying system in the application at hand, the robustness with respect to errors in the model of underlying system, the availability of the training procedure and finally, the simplicity of filter representation, analysis, design and implementation. Simulation studies also indicate that the new filters are computationally attractive and have excellent performance in environments corrupted by bit errors and impulsive noise.

  15. Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

    Directory of Open Access Journals (Sweden)

    Jianke Li

    2014-01-01

    Full Text Available Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.

  16. Collaborative Filtering Recommendation on Users' Interest Sequences.

    Directory of Open Access Journals (Sweden)

    Weijie Cheng

    Full Text Available As an important factor for improving recommendations, time information has been introduced to model users' dynamic preferences in many papers. However, the sequence of users' behaviour is rarely studied in recommender systems. Due to the users' unique behavior evolution patterns and personalized interest transitions among items, users' similarity in sequential dimension should be introduced to further distinguish users' preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users' interest sequences (IS that rank users' ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users' longest common sub-IS (LCSIS and the count of users' total common sub-IS (ACSIS. Then, these semantics are utilized to obtain users' IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users' preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction.

  17. Collaborative Filtering Recommendation on Users' Interest Sequences.

    Science.gov (United States)

    Cheng, Weijie; Yin, Guisheng; Dong, Yuxin; Dong, Hongbin; Zhang, Wansong

    2016-01-01

    As an important factor for improving recommendations, time information has been introduced to model users' dynamic preferences in many papers. However, the sequence of users' behaviour is rarely studied in recommender systems. Due to the users' unique behavior evolution patterns and personalized interest transitions among items, users' similarity in sequential dimension should be introduced to further distinguish users' preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users' interest sequences (IS) that rank users' ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users' longest common sub-IS (LCSIS) and the count of users' total common sub-IS (ACSIS). Then, these semantics are utilized to obtain users' IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users' preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction.

  18. Collaborative Filtering Recommendation on Users’ Interest Sequences

    Science.gov (United States)

    Cheng, Weijie; Yin, Guisheng; Dong, Yuxin; Dong, Hongbin; Zhang, Wansong

    2016-01-01

    As an important factor for improving recommendations, time information has been introduced to model users’ dynamic preferences in many papers. However, the sequence of users’ behaviour is rarely studied in recommender systems. Due to the users’ unique behavior evolution patterns and personalized interest transitions among items, users’ similarity in sequential dimension should be introduced to further distinguish users’ preferences and interests. In this paper, we propose a new collaborative filtering recommendation method based on users’ interest sequences (IS) that rank users’ ratings or other online behaviors according to the timestamps when they occurred. This method extracts the semantics hidden in the interest sequences by the length of users’ longest common sub-IS (LCSIS) and the count of users’ total common sub-IS (ACSIS). Then, these semantics are utilized to obtain users’ IS-based similarities and, further, to refine the similarities acquired from traditional collaborative filtering approaches. With these updated similarities, transition characteristics and dynamic evolution patterns of users’ preferences are considered. Our new proposed method was compared with state-of-the-art time-aware collaborative filtering algorithms on datasets MovieLens, Flixster and Ciao. The experimental results validate that the proposed recommendation method is effective and outperforms several existing algorithms in the accuracy of rating prediction. PMID:27195787

  19. A THEORETICAL STUDY ON SIMPLIFIED KALMAN FILTER IN DATA ASSIMILATION

    Institute of Scientific and Technical Information of China (English)

    Ma Zhai-pu; Huang Da-ji; Zhang Ben-zhao

    2003-01-01

    In this paper, we put forward a new method to reduce the calculation amount of the gain matrix of Kalman filter in data assimilation. We rewrite the vector describing the total state variables with two vectors whose dimensions are small and thus obtain the main parts and the trivial parts of the state variables. On the basis of the rewrittten formula, we not only develop a reduced Kalman filter scheme, but also obtain the transition equations about truncation errors, with which the validity of the main parts acting for the total state variables can be evaluated quantitatively. The error transition equations thus offer an indirect testimony to the rationality of the main parts.

  20. Changing ventilation filters

    International Nuclear Information System (INIS)

    Hackney, S.

    1980-01-01

    A filter changing unit has a door which interlocks with the door of a filter chamber so as to prevent contamination of the outer surfaces of the doors by radioactive material collected on the filter element and a movable support which enables a filter chamber thereonto to be stored within the unit in such a way that the doors of the unit and the filter chamber can be replaced. The door pivots and interlocks with another door by means of a bolt, a seal around the periphery lip of the first door engages the periphery of the second door to seal the gap. A support pivots into a lower filter element storage position. Inspection windows and glove ports are provided. The unit is releasably connected to the filter chamber by bolts engaging in a flange provided around an opening. (author)

  1. Extended Stable Boundary of LCL-Filtered Grid-Connected Inverter Based on An Improved Grid-Voltage Feedforward Control

    DEFF Research Database (Denmark)

    Lu, Minghui; Xin, Zhen; Wang, Xiongfei

    2016-01-01

    should be designed under one-sixth of sampling frequency. However, the low resonance frequency leads to a comparatively large filter inductance or/and capacitance. To extend the stable boundary to the region above fs/6, this paper proposes a novel voltage feedforward scheme for the LCL-filtered inverter....... Theoretical analysis is then provided to validate its feasibility and stability. Compared to other widely used active damping strategies, no extra sensors are needed because the filter capacitor voltage, which is used for voltage feedforward control, is also sampled for phase-locked loop in this paper...

  2. Device for automatic filter changing. Einrichtung zum selbsttaetigen Wechseln eines Filters

    Energy Technology Data Exchange (ETDEWEB)

    Matschoss, V; Naschwitz, A; Wild, H

    1984-01-05

    A filter is moved from a store to an aerosol pipe by a lifting device and is clamped there. At the end of the operating period, the lifting device moves a new filter to a parking place. Control is from limit switches of the lifting, clamping and thrust devices and the position control of the store is by the limit switches. The filter changing device is enclosed in a gastight case, prevents blockage of a filter and makes it possible to set a certain operating period, to change the filter without interrupting the aerosol flow and to measure each filter in the sequence of operation outside the aerosol flow.

  3. Quantum neural network-based EEG filtering for a brain-computer interface.

    Science.gov (United States)

    Gandhi, Vaibhav; Prasad, Girijesh; Coyle, Damien; Behera, Laxmidhar; McGinnity, Thomas Martin

    2014-02-01

    A novel neural information processing architecture inspired by quantum mechanics and incorporating the well-known Schrodinger wave equation is proposed in this paper. The proposed architecture referred to as recurrent quantum neural network (RQNN) can characterize a nonstationary stochastic signal as time-varying wave packets. A robust unsupervised learning algorithm enables the RQNN to effectively capture the statistical behavior of the input signal and facilitates the estimation of signal embedded in noise with unknown characteristics. The results from a number of benchmark tests show that simple signals such as dc, staircase dc, and sinusoidal signals embedded within high noise can be accurately filtered and particle swarm optimization can be employed to select model parameters. The RQNN filtering procedure is applied in a two-class motor imagery-based brain-computer interface where the objective was to filter electroencephalogram (EEG) signals before feature extraction and classification to increase signal separability. A two-step inner-outer fivefold cross-validation approach is utilized to select the algorithm parameters subject-specifically for nine subjects. It is shown that the subject-specific RQNN EEG filtering significantly improves brain-computer interface performance compared to using only the raw EEG or Savitzky-Golay filtered EEG across multiple sessions.

  4. Gaussian mixture probability hypothesis density filter for multipath multitarget tracking in over-the-horizon radar

    Science.gov (United States)

    Qin, Yong; Ma, Hong; Chen, Jinfeng; Cheng, Li

    2015-12-01

    Conventional multitarget tracking systems presume that each target can produce at most one measurement per scan. Due to the multiple ionospheric propagation paths in over-the-horizon radar (OTHR), this assumption is not valid. To solve this problem, this paper proposes a novel tracking algorithm based on the theory of finite set statistics (FISST) called the multipath probability hypothesis density (MP-PHD) filter in cluttered environments. First, the FISST is used to derive the update equation, and then Gaussian mixture (GM) is introduced to derive the closed-form solution of the MP-PHD filter. Moreover, the extended Kalman filter (EKF) is presented to deal with the nonlinear problem of the measurement model in OTHR. Eventually, the simulation results are provided to demonstrate the effectiveness of the proposed filter.

  5. Sensory pollution from bag-type fiberglass ventilation filters: Conventional filter compared with filters containing various amounts of activated carbon

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Fadeyi, M.O.; Clausen, Geo

    2009-01-01

    filter and three modifications of a bag-type fiberglass combination filter: the "Heavy" corresponded to a commercially available filter containing 400 g of carbon per square meter of filter area, the "Medium" contained half as much carbon (200 g/m(2)), and the "Light" contained a quarter as much carbon...

  6. Three-Input Single-Output Voltage-Mode Multifunction Filter with Electronic Controllability Based on Single Commercially Available IC

    Directory of Open Access Journals (Sweden)

    Supachai Klungtong

    2017-01-01

    Full Text Available This paper presents a second-order voltage-mode filter with three inputs and single-output voltage using single commercially available IC, one resistor, and two capacitors. The used commercially available IC, called LT1228, is manufactured by Linear Technology Corporation. The proposed filter is based on parallel RLC circuit. The filter provides five output filter responses, namely, band-pass (BP, band-reject (BR, low-pass (LP, high-pass (HP, and all-pass (AP functions. The selection of each filter response can be done without the requirement of active and passive component matching condition. Furthermore, the natural frequency and quality factor are electronically controlled. Besides, the nonideal case is also investigated. The output voltage node exhibits low impedance. The experimental results can validate the theoretical analyses.

  7. A Differential Geometric Approach to Nonlinear Filtering: The Projection Filter

    NARCIS (Netherlands)

    Brigo, D.; Hanzon, B.; LeGland, F.

    1998-01-01

    This paper presents a new and systematic method of approximating exact nonlinear filters with finite dimensional filters, using the differential geometric approach to statistics. The projection filter is defined rigorously in the case of exponential families. A convenient exponential family is

  8. Filter and Filter Bank Design for Image Texture Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Randen, Trygve

    1997-12-31

    The relevance of this thesis to energy and environment lies in its application to remote sensing such as for instance sea floor mapping and seismic pattern recognition. The focus is on the design of two-dimensional filters for feature extraction, segmentation, and classification of digital images with textural content. The features are extracted by filtering with a linear filter and estimating the local energy in the filter response. The thesis gives a review covering broadly most previous approaches to texture feature extraction and continues with proposals of some new techniques. 143 refs., 59 figs., 7 tabs.

  9. HEPA Filter Vulnerability Assessment

    International Nuclear Information System (INIS)

    GUSTAVSON, R.D.

    2000-01-01

    This assessment of High Efficiency Particulate Air (HEPA) filter vulnerability was requested by the USDOE Office of River Protection (ORP) to satisfy a DOE-HQ directive to evaluate the effect of filter degradation on the facility authorization basis assumptions. Within the scope of this assessment are ventilation system HEPA filters that are classified as Safety-Class (SC) or Safety-Significant (SS) components that perform an accident mitigation function. The objective of the assessment is to verify whether HEPA filters that perform a safety function during an accident are likely to perform as intended to limit release of hazardous or radioactive materials, considering factors that could degrade the filters. Filter degradation factors considered include aging, wetting of filters, exposure to high temperature, exposure to corrosive or reactive chemicals, and exposure to radiation. Screening and evaluation criteria were developed by a site-wide group of HVAC engineers and HEPA filter experts from published empirical data. For River Protection Project (RPP) filters, the only degradation factor that exceeded the screening threshold was for filter aging. Subsequent evaluation of the effect of filter aging on the filter strength was conducted, and the results were compared with required performance to meet the conditions assumed in the RPP Authorization Basis (AB). It was found that the reduction in filter strength due to aging does not affect the filter performance requirements as specified in the AB. A portion of the HEPA filter vulnerability assessment is being conducted by the ORP and is not part of the scope of this study. The ORP is conducting an assessment of the existing policies and programs relating to maintenance, testing, and change-out of HEPA filters used for SC/SS service. This document presents the results of a HEPA filter vulnerability assessment conducted for the River protection project as requested by the DOE Office of River Protection

  10. Ensemble Kalman filter regularization using leave-one-out data cross-validation

    KAUST Repository

    Rayo Schiappacasse, Lautaro Jerónimo

    2012-09-19

    In this work, the classical leave-one-out cross-validation method for selecting a regularization parameter for the Tikhonov problem is implemented within the EnKF framework. Following the original concept, the regularization parameter is selected such that it minimizes the predictive error. Some ideas about the implementation, suitability and conceptual interest of the method are discussed. Finally, what will be called the data cross-validation regularized EnKF (dCVr-EnKF) is implemented in a 2D 2-phase synthetic oil reservoir experiment and the results analyzed.

  11. Filtering of Discrete-Time Switched Neural Networks Ensuring Exponential Dissipative and $l_{2}$ - $l_{\\infty }$ Performances.

    Science.gov (United States)

    Choi, Hyun Duck; Ahn, Choon Ki; Karimi, Hamid Reza; Lim, Myo Taeg

    2017-10-01

    This paper studies delay-dependent exponential dissipative and l 2 - l ∞ filtering problems for discrete-time switched neural networks (DSNNs) including time-delayed states. By introducing a novel discrete-time inequality, which is a discrete-time version of the continuous-time Wirtinger-type inequality, we establish new sets of linear matrix inequality (LMI) criteria such that discrete-time filtering error systems are exponentially stable with guaranteed performances in the exponential dissipative and l 2 - l ∞ senses. The design of the desired exponential dissipative and l 2 - l ∞ filters for DSNNs can be achieved by solving the proposed sets of LMI conditions. Via numerical simulation results, we show the validity of the desired discrete-time filter design approach.

  12. Potential for HEPA filter damage from water spray systems in filter plenums

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W. [Lawrence Livermore National Lab., CA (United States); Fretthold, J.K. [Rocky Flats Safe Sites of Colorado, Golden, CO (United States); Slawski, J.W. [Department of Energy, Germantown, MD (United States)

    1997-08-01

    The water spray systems in high efficiency particulate air (HEPA) filter plenums that are used in nearly all Department of Energy (DOE) facilities for protection against fire was designed under the assumption that the HEPA filters would not be damaged by the water sprays. The most likely scenario for filter damage involves filter plugging by the water spray, followed by the fan blowing out the filter medium. A number of controlled laboratory tests that were previously conducted in the late 1980s are reviewed in this paper to provide a technical basis for the potential HEPA filter damage by the water spray system in HEPA filter plenums. In addition to the laboratory tests, the scenario for BEPA filter damage during fires has also occurred in the field. A fire in a four-stage, BEPA filter plenum at Rocky Flats in 1980 caused the first three stages of BEPA filters to blow out of their housing and the fourth stage to severely bow. Details of this recently declassified fire are presented in this paper. Although these previous findings suggest serious potential problems exist with the current water spray system in filter plenums, additional studies are required to confirm unequivocally that DOE`s critical facilities are at risk. 22 refs., 15 figs.

  13. Single DV-DXCCII Based Voltage Controlled First Order All-pass Filter with Inverting and Non-inverting responses

    Directory of Open Access Journals (Sweden)

    B Chaturvedi

    2015-12-01

    Full Text Available In this paper, a new voltage controlled first order all-pass filter is presented. The proposed circuit employs a single differential voltage dual-X second generation current conveyor (DV-DXCCII and a grounded capacitor only. The proposed all-pass filter provides both inverting and non inverting voltage-mode outputs from the same configuration simultaneously without any matching condition. Non-ideal analysis along with sensitivity analysis is also investigated. The proposed circuit has low active and passive sensitivities. As an application the proposed all-pass filter is connected in cascade to get higher order filter. The theoretical results are validated thorough PSPICE simulations using TSMC 0.18µm CMOS process parameters.

  14. Deep learning architecture for iris recognition based on optimal Gabor filters and deep belief network

    Science.gov (United States)

    He, Fei; Han, Ye; Wang, Han; Ji, Jinchao; Liu, Yuanning; Ma, Zhiqiang

    2017-03-01

    Gabor filters are widely utilized to detect iris texture information in several state-of-the-art iris recognition systems. However, the proper Gabor kernels and the generative pattern of iris Gabor features need to be predetermined in application. The traditional empirical Gabor filters and shallow iris encoding ways are incapable of dealing with such complex variations in iris imaging including illumination, aging, deformation, and device variations. Thereby, an adaptive Gabor filter selection strategy and deep learning architecture are presented. We first employ particle swarm optimization approach and its binary version to define a set of data-driven Gabor kernels for fitting the most informative filtering bands, and then capture complex pattern from the optimal Gabor filtered coefficients by a trained deep belief network. A succession of comparative experiments validate that our optimal Gabor filters may produce more distinctive Gabor coefficients and our iris deep representations be more robust and stable than traditional iris Gabor codes. Furthermore, the depth and scales of the deep learning architecture are also discussed.

  15. Design-Oriented Analysis of Resonance Damping and Harmonic Compensation for LCL-Filtered Voltage Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    This paper addresses the interaction between harmonic resonant controllers and active damping of LCL resonance in voltage source converters. A virtual series R-C damper in parallel with the filter capacitor is proposed with the capacitor current feedback loop. The phase lag resulting from...... crossover frequency defined by the proportional gain of current controller. This is of particular interest for high-performance active harmonic filtering applications and low-pulse-ratio converters. Case studies in experiments validate the theoretical analysis....

  16. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    activated carbon and are often used following ozonation to remove additional biodegradable organics created during ozonation. In Europe, biological filters are also used to remove ammonium and reduced forms of iron and manganese. These compounds can cause biological instability in the distribution system...... tracer, are performed during an operational cycle of a filter to examine how the filter flow changes with time. The data is used to validate a mathematical model that can both predict process performance and to gain an understanding of how dynamic conditions can influence filter performance....... The mathematical model developed is intended to assist in the design of new filters, set up of pilot plant studies, and as a tool to troubleshoot existing problems in full scale filters. Unlike previous models, the model developed accounts for the effects of particle/precipitate accumulation and its effects...

  17. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  18. Group hypnotherapy versus group relaxation for smoking cessation: an RCT study protocol

    Directory of Open Access Journals (Sweden)

    Dickson-Spillmann Maria

    2012-04-01

    Full Text Available Abstract Background A significant number of smokers would like to stop smoking. Despite the demonstrated efficacy of pharmacological smoking cessation treatments, many smokers are unwilling to use them; however, they are inclined to try alternative methods. Hypnosis has a long-standing reputation in smoking cessation therapy, but its efficacy has not been scientifically proven. We designed this randomised controlled trial to evaluate the effects of group hypnosis as a method for smoking cessation, and we will compare the results of group hypnosis with group relaxation. Methods/Design This is a randomised controlled trial (RCT to compare the efficacy of a single session of hypnosis with that of relaxation performed in groups of 8-15 smokers. We intend to include at least 220 participants in our trial. The inclusion criteria include smoking at least 5 cigarettes per day, not using other cessation methods and being willing to quit smoking. The intervention is performed by a trained hypnotist/relaxation therapist. Both groups first receive 40 min of mental preparation that is based on motivational interviewing. Then, a state of deep relaxation is induced in the hypnosis condition, and superficial relaxation is induced in the control condition. Suggestions are made in the hypnosis condition that aim to switch the mental self-image of the participants from that of smokers to that of non-smokers. Each intervention lasts for 40 min. The participants also complete questionnaires that assess their smoking status and symptoms of depression and anxiety at baseline, 2 weeks and 6 months post-intervention. In addition, saliva samples are collected to assess cotinine levels at baseline and at 6 months post-intervention. We also assess nicotine withdrawal symptoms at 2 weeks post-intervention. Discussion To the best of our knowledge, this RCT is the first to test the efficacy of group hypnosis versus group relaxation. Issues requiring discussion in the outcome

  19. Miniaturized dielectric waveguide filters

    OpenAIRE

    Sandhu, MY; Hunter, IC

    2016-01-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  20. Hybrid Filter Membrane

    Science.gov (United States)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  1. HIGH-PRECISION ATTITUDE ESTIMATION METHOD OF STAR SENSORS AND GYRO BASED ON COMPLEMENTARY FILTER AND UNSCENTED KALMAN FILTER

    Directory of Open Access Journals (Sweden)

    C. Guo

    2017-07-01

    Full Text Available Determining the attitude of satellite at the time of imaging then establishing the mathematical relationship between image points and ground points is essential in high-resolution remote sensing image mapping. Star tracker is insensitive to the high frequency attitude variation due to the measure noise and satellite jitter, but the low frequency attitude motion can be determined with high accuracy. Gyro, as a short-term reference to the satellite’s attitude, is sensitive to high frequency attitude change, but due to the existence of gyro drift and integral error, the attitude determination error increases with time. Based on the opposite noise frequency characteristics of two kinds of attitude sensors, this paper proposes an on-orbit attitude estimation method of star sensors and gyro based on Complementary Filter (CF and Unscented Kalman Filter (UKF. In this study, the principle and implementation of the proposed method are described. First, gyro attitude quaternions are acquired based on the attitude kinematics equation. An attitude information fusion method is then introduced, which applies high-pass filtering and low-pass filtering to the gyro and star tracker, respectively. Second, the attitude fusion data based on CF are introduced as the observed values of UKF system in the process of measurement updating. The accuracy and effectiveness of the method are validated based on the simulated sensors attitude data. The obtained results indicate that the proposed method can suppress the gyro drift and measure noise of attitude sensors, improving the accuracy of the attitude determination significantly, comparing with the simulated on-orbit attitude and the attitude estimation results of the UKF defined by the same simulation parameters.

  2. Compact triple band-stop filter using novel epsilon-shaped metamaterial with lumped capacitor

    Science.gov (United States)

    Ali, W. A. E.; Hamdalla, M. Z. M.

    2018-04-01

    This paper presents the design of a novel epsilon-shaped metamaterial unit cell structure that is applicable for single-band and multi-band applications. A closed-form formulas to control the resonance frequencies of the proposed design are included. The proposed unit cell, which exhibits negative permeability at its frequency bands, is etched from the ground plane to form a band-stop filter. The filter design is constructed to validate the band-notched characteristics of the proposed unit cell. A lumped capacitor is inserted for size reduction purpose in addition to multi-resonance generation. The fundamental resonance frequency is translated from 3.62 GHz to 2.45 GHz, which means that the filter size will be more compact (more than 32% size reduction). The overall size of the proposed filter is 13 × 6 × 1.524 mm3, where the electrical size is 0.221λg × 0.102λg × 0.026λg at the lower frequency band (2.45 GHz). Two other resonance frequencies are generated at 5.3 GHz and 9.2 GHz, which confirm the multi-band behavior of the proposed filter. Good agreement between simulated and measured characteristics of the fabricated filter prototype is achieved.

  3. Enhancing search efficiency by means of a search filter for finding all studies on animal experimentation in PubMed.

    Science.gov (United States)

    Hooijmans, Carlijn R; Tillema, Alice; Leenaars, Marlies; Ritskes-Hoitinga, Merel

    2010-07-01

    Collecting and analysing all available literature before starting an animal experiment is important and it is indispensable when writing a systematic review (SR) of animal research. Writing such review prevents unnecessary duplication of animal studies and thus unnecessary animal use (Reduction). One of the factors currently impeding the production of 'high-quality' SRs in laboratory animal science is the fact that searching for all available literature concerning animal experimentation is rather difficult. In order to diminish these difficulties, we developed a search filter for PubMed to detect all publications concerning animal studies. This filter was compared with the method most frequently used, the PubMed Limit: Animals, and validated further by performing two PubMed topic searches. Our filter performs much better than the PubMed limit: it retrieves, on average, 7% more records. Other important advantages of our filter are that it also finds the most recent records and that it is easy to use. All in all, by using our search filter in PubMed, all available literature concerning animal studies on a specific topic can easily be found and assessed, which will help in increasing the scientific quality and thereby the ethical validity of animal experiments.

  4. Effects of preventive family service coordination for parents with mental illnesses and their children, a RCT.

    Science.gov (United States)

    Wansink, Henny J; Janssens, Jan M A M; Hoencamp, Erik; Middelkoop, Barend J C; Hosman, Clemens M H

    2015-06-01

    Children of parents with a mental illness (COPMI) are at increased risk for developing psychiatric disorders, especially when parenting is compromised by multiple risk factors. Due to fragmented services, these families often do not get the support they need. Can coordination between services, as developed in the Preventive Basic Care Management (PBCM) program, improve parenting and prevent child behavioral problems? This randomized controlled clinical trial (RCT) compared the effectiveness of PBCM with a control condition. Ninety-nine outpatients of a community mental health center were randomized to intervention or control. Primary outcomes included parenting quality (assessed by the HOME instrument), parenting skills (parenting skills subscale of FFQ), and parenting stress (PDH). Secondary outcomes are child behavioral problems (SDQ). Outcomes were assessed at baseline and after 9 and 18 months. Effects were analyzed by Repeated Measures Analysis of Variance. Most families were single-parent families belonging to ethnic minorities. The results of the first RCT on effects of PBCM suggest that this intervention is feasible and has a positive effect on parenting skills. There was no evidence for effects on the quality of parenting and parenting stress, nor preventive effects on child behavioral problems. Replication studies in other sites, with more power, including monitoring of the implementation quality and studying a broader palette of child outcomes are needed to confirm the positive effects of PBCM. Long-term prospective studies are needed to investigate if improved parenting skills lead to positive effects in the children in the long run. (c) 2015 APA, all rights reserved).

  5. Sampled data CT system including analog filter and compensating digital filter

    International Nuclear Information System (INIS)

    Glover, G. H.; DallaPiazza, D. G.; Pelc, N. J.

    1985-01-01

    A CT scanner in which the amount of x-ray information acquired per unit time is substantially increased by using a continuous-on x-ray source and a sampled data system with the detector. An analog filter is used in the sampling system for band limiting the detector signal below the highest frequency of interest, but is a practically realizable filter and is therefore non-ideal. A digital filter is applied to the detector data after digitization to compensate for the characteristics of the analog filter, and to provide an overall filter characteristic more nearly like the ideal

  6. Quick-change filter cartridge

    Science.gov (United States)

    Rodgers, John C.; McFarland, Andrew R.; Ortiz, Carlos A.

    1995-01-01

    A quick-change filter cartridge. In sampling systems for measurement of airborne materials, a filter element is introduced into the sampled airstream such that the aerosol constituents are removed and deposited on the filter. Fragile sampling media often require support in order to prevent rupture during sampling, and careful mounting and sealing to prevent misalignment, tearing, or creasing which would allow the sampled air to bypass the filter. Additionally, handling of filter elements may introduce cross-contamination or exposure of operators to toxic materials. Moreover, it is desirable to enable the preloading of filter media into quick-change cartridges in clean laboratory environments, thereby simplifying and expediting the filter-changing process in the field. The quick-change filter cartridge of the present invention permits the application of a variety of filter media in many types of instruments and may also be used in automated systems. The cartridge includes a base through which a vacuum can be applied to draw air through the filter medium which is located on a porous filter support and held there by means of a cap which forms an airtight seal with the base. The base is also adapted for receiving absorbing media so that both particulates and gas-phase samples may be trapped for investigation, the latter downstream of the aerosol filter.

  7. Evaluation of beam delivery and ripple filter design for non-isocentric proton and carbon ion therapy.

    Science.gov (United States)

    Grevillot, L; Stock, M; Vatnitsky, S

    2015-10-21

    This study aims at selecting and evaluating a ripple filter design compatible with non-isocentric proton and carbon ion scanning beam treatment delivery for a compact nozzle. The use of non-isocentric treatments when the patient is shifted as close as possible towards the nozzle exit allows for a reduction in the air gap and thus an improvement in the quality of scanning proton beam treatment delivery. Reducing the air gap is less important for scanning carbon ions, but ripple filters are still necessary for scanning carbon ion beams to reduce the number of energy steps required to deliver homogeneous SOBP. The proper selection of ripple filters also allows a reduction in the possible transverse and depth-dose inhomogeneities that could appear in non-isocentric conditions in particular. A thorough review of existing ripple filter designs over the past 16 years is performed and a design for non-isocentric treatment delivery is presented. A unique ripple filter quality index (QIRiFi) independent of the particle type and energy and representative of the ratio between energy modulation and induced scattering is proposed. The Bragg peak width evaluated at the 80% dose level (BPW80) is proposed to relate the energy modulation of the delivered Bragg peaks and the energy layer step size allowing the production of homogeneous SOBP. Gate/Geant4 Monte Carlo simulations have been validated for carbon ion and ripple filter simulations based on measurements performed at CNAO and subsequently used for a detailed analysis of the proposed ripple filter design. A combination of two ripple filters in a series has been validated for non-isocentric delivery and did not show significant transverse and depth-dose inhomogeneities. Non-isocentric conditions allow a significant reduction in the spot size at the patient entrance (up to 350% and 200% for protons and carbon ions with range shifter, respectively), and therefore in the lateral penumbra in the patients.

  8. Improved Kalman Filter-Based Speech Enhancement with Perceptual Post-Filtering

    Institute of Scientific and Technical Information of China (English)

    WEIJianqiang; DULimin; YANZhaoli; ZENGHui

    2004-01-01

    In this paper, a Kalman filter-based speech enhancement algorithm with some improvements of previous work is presented. A new technique based on spectral subtraction is used for separation speech and noise characteristics from noisy speech and for the computation of speech and noise Autoregressive (AR) parameters. In order to obtain a Kalman filter output with high audible quality, a perceptual post-filter is placed at the output of the Kalman filter to smooth the enhanced speech spectra.Extensive experiments indicate that this newly proposed method works well.

  9. Performance-Based Technology Selection Filter description report

    International Nuclear Information System (INIS)

    O'Brien, M.C.; Morrison, J.L.; Morneau, R.A.; Rudin, M.J.; Richardson, J.G.

    1992-05-01

    A formal methodology has been developed for identifying technology gaps and assessing innovative or postulated technologies for inclusion in proposed Buried Waste Integrated Demonstration (BWID) remediation systems. Called the Performance-Based Technology Selection Filter, the methodology provides a formalized selection process where technologies and systems are rated and assessments made based on performance measures, and regulatory and technical requirements. The results are auditable, and can be validated with field data. This analysis methodology will be applied to the remedial action of transuranic contaminated waste pits and trenches buried at the Idaho National Engineering Laboratory (INEL)

  10. Performance-Based Technology Selection Filter description report

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, M.C.; Morrison, J.L.; Morneau, R.A.; Rudin, M.J.; Richardson, J.G.

    1992-05-01

    A formal methodology has been developed for identifying technology gaps and assessing innovative or postulated technologies for inclusion in proposed Buried Waste Integrated Demonstration (BWID) remediation systems. Called the Performance-Based Technology Selection Filter, the methodology provides a formalized selection process where technologies and systems are rated and assessments made based on performance measures, and regulatory and technical requirements. The results are auditable, and can be validated with field data. This analysis methodology will be applied to the remedial action of transuranic contaminated waste pits and trenches buried at the Idaho National Engineering Laboratory (INEL).

  11. Method for cleaning the filter pockets of dust gas filter systems

    Energy Technology Data Exchange (ETDEWEB)

    Margraf, A

    1975-05-07

    The invention deals with a method to clean filter pockets filled with dust gas. By a periodic to and fro air jet attached to a scavenging blower, a pulsed fluttering movement of the filter surface is obtained which releases the outer layers of dust. The charging of the filter pockets with scavenging air to clean the filter material can be carried out immediately on the pulsed admission with suitable time control.

  12. BWR level estimation using Kalman Filtering approach

    International Nuclear Information System (INIS)

    Garner, G.; Divakaruni, S.M.; Meyer, J.E.

    1986-01-01

    Work is in progress on development of a system for Boiling Water Reactor (BWR) vessel level validation and failure detection. The levels validated include the liquid level both inside and outside the core shroud. This work is a major part of a larger effort to develop a complete system for BWR signal validation. The demonstration plant is the Oyster Creek BWR. Liquid level inside the core shroud is not directly measured during full power operation. This level must be validated using measurements of other quantities and analytic models. Given the available sensors, analytic models for level that are based on mass and energy balances can contain open integrators. When such a model is driven by noisy measurements, the model predicted level will deviate from the true level over time. To validate the level properly and to avoid false alarms, the open integrator must be stabilized. In addition, plant parameters will change slowly with time. The respective model must either account for these plant changes or be insensitive to them to avoid false alarms and maintain sensitivity to true failures of level instrumentation. Problems are addressed here by combining the extended Kalman Filter and Parity Space Decision/Estimator. The open integrator is stabilized by integrating from the validated estimate at the beginning of each sampling interval, rather than from the model predicted value. The model is adapted to slow plant/sensor changes by updating model parameters on-line

  13. A Digital Image Denoising Algorithm Based on Gaussian Filtering and Bilateral Filtering

    Directory of Open Access Journals (Sweden)

    Piao Weiying

    2018-01-01

    Full Text Available Bilateral filtering has been applied in the area of digital image processing widely, but in the high gradient region of the image, bilateral filtering may generate staircase effect. Bilateral filtering can be regarded as one particular form of local mode filtering, according to above analysis, an mixed image de-noising algorithm is proposed based on Gaussian filter and bilateral filtering. First of all, it uses Gaussian filter to filtrate the noise image and get the reference image, then to take both the reference image and noise image as the input for range kernel function of bilateral filter. The reference image can provide the image’s low frequency information, and noise image can provide image’s high frequency information. Through the competitive experiment on both the method in this paper and traditional bilateral filtering, the experimental result showed that the mixed de-noising algorithm can effectively overcome staircase effect, and the filtrated image was more smooth, its textural features was also more close to the original image, and it can achieve higher PSNR value, but the amount of calculation of above two algorithms are basically the same.

  14. Filtering Photogrammetric Point Clouds Using Standard LIDAR Filters Towards DTM Generation

    Science.gov (United States)

    Zhang, Z.; Gerke, M.; Vosselman, G.; Yang, M. Y.

    2018-05-01

    Digital Terrain Models (DTMs) can be generated from point clouds acquired by laser scanning or photogrammetric dense matching. During the last two decades, much effort has been paid to developing robust filtering algorithms for the airborne laser scanning (ALS) data. With the point cloud quality from dense image matching (DIM) getting better and better, the research question that arises is whether those standard Lidar filters can be used to filter photogrammetric point clouds as well. Experiments are implemented to filter two dense matching point clouds with different noise levels. Results show that the standard Lidar filter is robust to random noise. However, artefacts and blunders in the DIM points often appear due to low contrast or poor texture in the images. Filtering will be erroneous in these locations. Filtering the DIM points pre-processed by a ranking filter will bring higher Type II error (i.e. non-ground points actually labelled as ground points) but much lower Type I error (i.e. bare ground points labelled as non-ground points). Finally, the potential DTM accuracy that can be achieved by DIM points is evaluated. Two DIM point clouds derived by Pix4Dmapper and SURE are compared. On grassland dense matching generates points higher than the true terrain surface, which will result in incorrectly elevated DTMs. The application of the ranking filter leads to a reduced bias in the DTM height, but a slightly increased noise level.

  15. SU-E-J-145: Validation of An Analytical Model for in Vivo Range Verification Using GATE Monte Carlo Simulation in Proton Therapy

    International Nuclear Information System (INIS)

    Lee, C; Lin, H; Chao, T; Hsiao, I; Chuang, K

    2015-01-01

    Purpose: Predicted PET images on the basis of analytical filtering approach for proton range verification has been successful developed and validated using FLUKA Monte Carlo (MC) codes and phantom measurements. The purpose of the study is to validate the effectiveness of analytical filtering model for proton range verification on GATE/GEANT4 Monte Carlo simulation codes. Methods: In this study, we performed two experiments for validation of predicted β+-isotope by the analytical model with GATE/GEANT4 simulations. The first experiments to evaluate the accuracy of predicting β+-yields as a function of irradiated proton energies. In second experiment, we simulate homogeneous phantoms of different materials irradiated by a mono-energetic pencil-like proton beam. The results of filtered β+-yields distributions by the analytical model is compared with those of MC simulated β+-yields in proximal and distal fall-off ranges. Results: The results investigate the distribution between filtered β+-yields and MC simulated β+-yields distribution in different conditions. First, we found that the analytical filtering can be applied over the whole range of the therapeutic energies. Second, the range difference between filtered β+-yields and MC simulated β+-yields at the distal fall-off region are within 1.5mm for all materials used. The findings validated the usefulness of analytical filtering model on range verification of proton therapy on GATE Monte Carlo simulations. In addition, there is a larger discrepancy between filtered prediction and MC simulated β+-yields using GATE code, especially in proximal region. This discrepancy might Result from the absence of wellestablished theoretical models for predicting the nuclear interactions. Conclusion: Despite the fact that large discrepancies of the distributions between MC-simulated and predicted β+-yields were observed, the study prove the effectiveness of analytical filtering model for proton range verification using

  16. Bias aware Kalman filters

    DEFF Research Database (Denmark)

    Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

    2006-01-01

    This paper reviews two different approaches that have been proposed to tackle the problems of model bias with the Kalman filter: the use of a colored noise model and the implementation of a separate bias filter. Both filters are implemented with and without feedback of the bias into the model state....... The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved....

  17. Visible light communication using DC-biased optical filter bank multi-carrier modulation

    KAUST Repository

    Chen, Rui

    2018-03-19

    Filter bank multicarrier (FBMC) has become a promising candidate to replace conventional orthogonal frequency-division multiplexing (OFDM) scheme in 5G technology due to its better spectral confinement which results in a reduced inter-channel interference (ICI). However, the viability of using FBMC in visible light communication has not been verified. In this work we present the first experimental validation of the DC-biased optical filter bank multicarrier (DCO-FBMC) modulation scheme over a free-space optical channel. Under different receiving powers, up to three times bit error rate performance improvement has been achieved using DCO-FBMC with different overlapping factors compared to that of conventional DCO-OFDM.

  18. Visible light communication using DC-biased optical filter bank multi-carrier modulation

    KAUST Repository

    Chen, Rui; Park, Kihong; Shen, Chao; Ng, Tien Khee; Ooi, Boon S.; Alouini, Mohamed-Slim

    2018-01-01

    Filter bank multicarrier (FBMC) has become a promising candidate to replace conventional orthogonal frequency-division multiplexing (OFDM) scheme in 5G technology due to its better spectral confinement which results in a reduced inter-channel interference (ICI). However, the viability of using FBMC in visible light communication has not been verified. In this work we present the first experimental validation of the DC-biased optical filter bank multicarrier (DCO-FBMC) modulation scheme over a free-space optical channel. Under different receiving powers, up to three times bit error rate performance improvement has been achieved using DCO-FBMC with different overlapping factors compared to that of conventional DCO-OFDM.

  19. Study of different filters

    International Nuclear Information System (INIS)

    Cochinal, R.; Rouby, R.

    1959-01-01

    This note first contains a terminology related to filters and to their operation, and then proposes an overview of general characteristics of filters such as load loss with respect to gas rate, efficiency, and clogging with respect to filter pollution. It also indicates standard aerosols which are generally used, how they are dosed, and how efficiency is determined with a standard aerosol. Then, after a presentation of the filtration principle, this note reports the study of several filters: glass wool, filter papers provided by different companies, Teflon foam, English filters, Teflon wool, sintered Teflonite, quartz wool, polyvinyl chloride foam, synthetic filter, sintered bronze. The third part reports the study of some aerosol and dust separators

  20. Numerical Study on Self-Cleaning Canister Filter With Add-On Filter Cap

    Directory of Open Access Journals (Sweden)

    Mohammed Akmal Nizam

    2017-01-01

    Full Text Available Filtration in a turbo machinery system such as a gas turbine will ensure that the air entering the inlet is free from contaminants that could bring damage to the main system. Self-cleaning filter systems for gas turbines are designed for continuously efficient flow filtration. A good filter would be able to maintain its effectiveness over a longer time period, prolonging the duration between filter replacements and providing lower pressure drop over its operating lifetime. With this goal in mind, the current study is focused on the difference in pressure loss of the benchmark Salutary Avenue Self-cleaning filter in comparison to a new design with an add-on filter cap. Geometry for the add-on filter cap will be based from Salutary Avenue Manufacturing Sdn.Bhd. SOLIDWORKS software was used to model the geometry of the filter, while simulation analysis on the flow through the filter was done using Computational Fluid Dynamic (CFD software. The simulations are based on a low velocity condition, in which the parameter for the inlet velocity are set at 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s respectively. From the simulation data obtained for the inlet velocities considered, the pressure drop reduction of the modified filter compared to the benchmark was found to be between 7.59% and 30.18%. All in all, the modification of the filter cap produced a lower pressure drop in comparison with the benchmark filter; an improvement of 27.02% for the total pressure drop was obtained.

  1. Laboratory for filter testing

    Energy Technology Data Exchange (ETDEWEB)

    Paluch, W.

    1987-07-01

    Filters used for mine draining in brown coal surface mines are tested by the Mine Draining Department of Poltegor. Laboratory tests of new types of filters developed by Poltegor are analyzed. Two types of tests are used: tests of scale filter models and tests of experimental units of new filters. Design and operation of the test stands used for testing mechanical properties and hydraulic properties of filters for coal mines are described: dimensions, pressure fluctuations, hydraulic equipment. Examples of testing large-diameter filters for brown coal mines are discussed.

  2. Chlamyweb Study II: a randomised controlled trial (RCT) of an online offer of home-based Chlamydia trachomatis sampling in France.

    Science.gov (United States)

    Kersaudy-Rahib, Delphine; Lydié, Nathalie; Leroy, Chloé; March, Laura; Bébéar, Cécile; Arwidson, Pierre; de Barbeyrac, Bertille

    2017-05-01

    The number of cases of Chlamydia trachomatis (Ct) diagnosed has increased in the past 15 years in France as well as in other European countries. This paper reports a randomised controlled trial (RCT) to evaluate whether the offer of home-based testing over the internet increased the number of young people tested for chlamydia compared with the current testing strategy and to estimate the number and risks factors of the infected population. This RCT took place as an element of the Chlamyweb Study-a study aiming to evaluate an intervention (the Chlamyweb Intervention) involving the offer of a free self-sampling kit online to sexually active men and women aged 18-24 years in France. Participants in the Chlamyweb RCT (n=11 075) received either an offer of a free self-sampling kit (intervention group) or were invited to be screened in primary care settings (control group). Risks ratios were used to compare screening rates between the intervention and control groups. Risk factors were analysed for infected people in the intervention group. The screening frequency was about three times higher among young people who received a self-sampling kit than those who only received a tailored recommendation to be screened (29.2% vs 8.7%). Although rates of screening among men were lower than among women (23.9% vs 33.9%), the intervention effect was greater among men (adjusted risk ratios (aRR)=4.55 vs aRR=2.94). Ct positivity (6.8%) was similar to that observed in STI clinics. It was higher in women (8.3%) than in men (4.4%). These results invite us to consider the establishment of a large home-based screening programme, although additional studies including economic assessments are needed to evaluate the most appropriate combination of strategies in the French context. AFFSAPS n° IDRCB 0211-A01000-41; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  3. Simulasi Filter Pasif Dan Perbandingan Unjuk Kerjanya Dengan Filter Aktif Dan Filter Aktif Hibrid Dalam Meredam Harmonisa Pada Induction Furnace

    OpenAIRE

    Tanoto, Yusak; Limantara, Limboto; Khandy Lestanto, Khristian

    2005-01-01

    This paper describe about simulation of Passive Filter in analysis to reduce harmonics that happened in a load such as vacuum casting induction furnace 9 kW, 13.8 kVA, 200V, 3 Ph, 50/60 Hz, also gives comparison with Hybrid Active Filter and Active Filter which made satisfaction result on the previous research. The best result achieved on the use of Hybrid Active Filter on %ITHD for 4.27 % and %VTHD for 3.83%, while Active Filter gave on %ITHD for 5.14 % and %VTHD for 3.82%. There ...

  4. Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

    International Nuclear Information System (INIS)

    Houry, M.P.; Bourles, H.

    1996-01-01

    The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this speed is a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band, i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit or rather an islanding. It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms. We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth to the speed measure. If one uses conventional methods to obtain a band stop filter, it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman'a theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a while noise. The resulting Kalman filter is an effective band stop filter, whose phase nicely remains near zero in the whole pass-band. The digital simulations we made and the tests we carried out with the Electricite de France Micro Network laboratory show the advantages of the rotation speed filter we designed using Kalman's theory. With the proposed filter, the speed measure filtering is better in terms of reduction and phase shift. the result is that there are less untimely solicitations of the fast valving system. Consequently, this device improves the power systems stability by minimizing the risks of deep perturbations due to a temporary lack of generation and the risks of under-speed loss

  5. The dry filter method for passive filtered venting of the containment

    International Nuclear Information System (INIS)

    Freis, Daniel; Tietsch, Wolfgang; Obenland, Ralf; Kroes, Bert; Martinsteg, Hans

    2013-01-01

    Filtered Venting is a mitigative emergency measure to protect the containment from pressure failure in case of a severe accident. Filtered vent systems which are based on the Dry Filter Method (DFM) are proven technology, work completely passive, meet all functional requirements and show excellent performance with respect to filter efficiency. With such a system the release of radioactive fission products to the environment can be effectively minimized. Short and long term land contaminations can be avoided. (orig.)

  6. Generalized Selection Weighted Vector Filters

    Directory of Open Access Journals (Sweden)

    Rastislav Lukac

    2004-09-01

    Full Text Available This paper introduces a class of nonlinear multichannel filters capable of removing impulsive noise in color images. The here-proposed generalized selection weighted vector filter class constitutes a powerful filtering framework for multichannel signal processing. Previously defined multichannel filters such as vector median filter, basic vector directional filter, directional-distance filter, weighted vector median filters, and weighted vector directional filters are treated from a global viewpoint using the proposed framework. Robust order-statistic concepts and increased degree of freedom in filter design make the proposed method attractive for a variety of applications. Introduced multichannel sigmoidal adaptation of the filter parameters and its modifications allow to accommodate the filter parameters to varying signal and noise statistics. Simulation studies reported in this paper indicate that the proposed filter class is computationally attractive, yields excellent performance, and is able to preserve fine details and color information while efficiently suppressing impulsive noise. This paper is an extended version of the paper by Lukac et al. presented at the 2003 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03 in Grado, Italy.

  7. Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

    International Nuclear Information System (INIS)

    Houry, M.P.; Bourles, H.

    1995-11-01

    The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this sped a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band. i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit (to contribute to the stability) or after an islanding (to quickly reach a balance with the house load). It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms; We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth of the speed measure. If one uses conventional methods to obtain a band-stop filter (for instance a Butterworth, a Chebyshev or an elliptic band-stop filter),it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman's theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a white noise. The resulting Kalman filter is an effective band-stop filter, whose phase nicely remains near zero in the whole pass-band. (authors). 13 refs., 12 figs

  8. Optimization of filter loading

    International Nuclear Information System (INIS)

    Turney, J.H.; Gardiner, D.E.; Sacramento Municipal Utility District, Herald, CA)

    1985-01-01

    The introduction of 10 CFR Part 61 has created potential difficulties in the disposal of spent cartridge filters. When this report was prepared, Rancho Seco had no method of packaging and disposing of class B or C filters. This work examined methods to minimize the total operating cost of cartridge filters while maintaining them below the class A limit. It was found that by encapsulating filters in cement the filter operating costs could be minimized

  9. Passivity-based design of robust passive damping for LCL-filtered voltage source converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    Passive damping is proven as a robust stabilizing technique for LCL-filtered voltage source converters. However, conventional design methods of passive dampers are based on the passive components only, while the inherent damping effect of time delay in the digital control system is overlooked....... In this paper, a frequency-domain passivity-based design approach is proposed, where the passive dampers are designed to eliminate the negative real part of the converter output admittance with closed-loop current control, rather than shaping the LCL-filter itself. Thus, the influence of time delay...... in the current control is included, which allows a relaxed design of the passive damper with the reduced power loss and improved stability robustness against grid parameters variations. Design procedures of two commonly used passive dampers with LCL-filtered VSCs are illustrated. Experimental results validate...

  10. Retrievable Vena Cava Filters in Major Trauma Patients: Prevalence of Thrombus Within the Filter

    International Nuclear Information System (INIS)

    Mahrer, Arie; Zippel, Douglas; Garniek, Alexander; Golan, Gil; Bensaid, Paul; Simon, Daniel; Rimon, Uri

    2008-01-01

    The purpose of this study was to report the prevalence of thrombus within a retrievable vena cava filter inserted prophylactically in major trauma patients referred for filter extraction. Between November 2002 and August 2005, 80 retrievable inferior vena cava filters (68 Optease and 12 Gunther-Tulip) were inserted into critically injured trauma patients (mean injury severity score 33.5). The filters were inserted within 1 to 6 (mean 2) days of injury. Thirty-seven patients were referred for filter removal (32 with Optease and 5 with Gunther-Tulip). The indwelling time was 7 to 22 (mean 13) days. All patients underwent inferior vena cavography prior to filter removal. There were no insertion-related complications and all filters were successfully deployed. Forty-three (54%) of the 80 patients were not referred for filter removal, as these patients continued to have contraindications to anticoagulation. Thirty-seven patients (46%) were referred for filter removal. In eight of them (22%) a large thrombus was seen within the filters and they were left in place, all with the Optease device. The other 29 filters (36%) were removed uneventfully.We conclude that the relatively high prevalence of intrafilter thrombi with the Optease filter may be explained by either spontaneous thrombus formation or captured emboli.

  11. Physical characteristics of the paper filter and low cafestol content filter coffee brews.

    Science.gov (United States)

    Rendón, Mery Yovana; Dos Santos Scholz, Maria Brígida; Bragagnolo, Neura

    2018-06-01

    The results found in the literature concerning the effect of consuming filter coffee brews on increasing the blood cholesterol levels due to the presence of diterpenes, are divergent. Thus the present research evaluated the diterpene (cafestol and kahweol) concentrations in filter coffee brews prepared with paper filters of different sizes, colors and origins (Brazil, Japan, The United States of America, Germany, France and the Netherlands), with and without micro perforations. This is the first study that reports the physical characteristics of paper filter and its importance to obtain filter coffee brew with low cafestol content. Thus, a sample of Catuai cultivar coffee with high cafestol content was roasted to a medium-light degree and used to prepare the brews in a 1:10 ratio (coffee powder to water). The diterpenes were extracted by direct saponification and quantified and identified by HPLC-DAD-MS/MS. The paper filters were physically characterized by measuring their grammage, and the fat permeation rate calculated in order to better understand the differences between the filters which allow one to obtain higher or lower diterpene contents. The cafestol and kahweol concentrations in the brews varied from 1.62 to 2.98 mg/L and from 0.73 to 1.96 mg/L, respectively. The highest cafestol and kahweol concentrations were obtained using paper filters with micro perforations, considering similar sized paper filters. The paper filters showed high fat permeability and grammages between 50.46 and 67.48 g/m 2 . The diterpene retention capacities of the filters produced in the different countries were similar. The results showed that the porosity of the paper filter and the particle size of the ground roasted coffee were determinant factors in obtaining filter coffee brews with lower cafestol contents. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Robust Huber-based iterated divided difference filtering with application to cooperative localization of autonomous underwater vehicles.

    Science.gov (United States)

    Gao, Wei; Liu, Yalong; Xu, Bo

    2014-12-19

    A new algorithm called Huber-based iterated divided difference filtering (HIDDF) is derived and applied to cooperative localization of autonomous underwater vehicles (AUVs) supported by a single surface leader. The position states are estimated using acoustic range measurements relative to the leader, in which some disadvantages such as weak observability, large initial error and contaminated measurements with outliers are inherent. By integrating both merits of iterated divided difference filtering (IDDF) and Huber's M-estimation methodology, the new filtering method could not only achieve more accurate estimation and faster convergence contrast to standard divided difference filtering (DDF) in conditions of weak observability and large initial error, but also exhibit robustness with respect to outlier measurements, for which the standard IDDF would exhibit severe degradation in estimation accuracy. The correctness as well as validity of the algorithm is demonstrated through experiment results.

  13. Two-shot fringe pattern phase-amplitude demodulation using Gram-Schmidt orthonormalization with Hilbert-Huang pre-filtering.

    Science.gov (United States)

    Trusiak, Maciej; Patorski, Krzysztof

    2015-02-23

    Gram-Schmidt orthonormalization is a very fast and efficient method for the fringe pattern phase demodulation. It requires only two arbitrarily phase-shifted frames. Images are treated as vectors and upon orthogonal projection of one fringe vector onto another the quadrature fringe pattern pair is obtained. Orthonormalization process is very susceptible, however, to noise, uneven background and amplitude modulation fluctuations. The Hilbert-Huang transform based preprocessing is proposed to enhance fringe pattern phase demodulation by filtering out the spurious noise and background illumination and performing fringe normalization. The Gram-Schmidt orthonormalization process error analysis is provided and its filtering-expanded capabilities are corroborated analyzing DSPI fringes and performing amplitude demodulation of Bessel fringes. Synthetic and experimental fringe pattern analyses presented to validate the proposed technique show that it compares favorably with other pre-filtering schemes, i.e., Gaussian filtering and continuous wavelet transform.

  14. Design, control, and implementation of LCL-filter-based shunt active power filters

    DEFF Research Database (Denmark)

    Tang, Yi; Loh, Poh Chiang; Wang, Peng

    2011-01-01

    This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offer......-loop control system, and active damping implemented with fewer current sensors are all addressed here. An analytical design example is finally presented, being supported with experimental results, to verify its effectiveness and practicality.......This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offers...

  15. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  16. Particle Kalman Filtering: A Nonlinear Framework for Ensemble Kalman Filters

    KAUST Repository

    Hoteit, Ibrahim

    2010-09-19

    Optimal nonlinear filtering consists of sequentially determining the conditional probability distribution functions (pdf) of the system state, given the information of the dynamical and measurement processes and the previous measurements. Once the pdfs are obtained, one can determine different estimates, for instance, the minimum variance estimate, or the maximum a posteriori estimate, of the system state. It can be shown that, many filters, including the Kalman filter (KF) and the particle filter (PF), can be derived based on this sequential Bayesian estimation framework. In this contribution, we present a Gaussian mixture‐based framework, called the particle Kalman filter (PKF), and discuss how the different EnKF methods can be derived as simplified variants of the PKF. We also discuss approaches to reducing the computational burden of the PKF in order to make it suitable for complex geosciences applications. We use the strongly nonlinear Lorenz‐96 model to illustrate the performance of the PKF.

  17. Non-Euclidean phasor analysis for quantification of oxidative stress in ex vivo human skin exposed to sun filters using fluorescence lifetime imaging microscopy

    Science.gov (United States)

    Osseiran, Sam; Roider, Elisabeth M.; Wang, Hequn; Suita, Yusuke; Murphy, Michael; Fisher, David E.; Evans, Conor L.

    2017-12-01

    Chemical sun filters are commonly used as active ingredients in sunscreens due to their efficient absorption of ultraviolet (UV) radiation. Yet, it is known that these compounds can photochemically react with UV light and generate reactive oxygen species and oxidative stress in vitro, though this has yet to be validated in vivo. One label-free approach to probe oxidative stress is to measure and compare the relative endogenous fluorescence generated by cellular coenzymes nicotinamide adenine dinucleotides and flavin adenine dinucleotides. However, chemical sun filters are fluorescent, with emissive properties that contaminate endogenous fluorescent signals. To accurately distinguish the source of fluorescence in ex vivo skin samples treated with chemical sun filters, fluorescence lifetime imaging microscopy data were processed on a pixel-by-pixel basis using a non-Euclidean separation algorithm based on Mahalanobis distance and validated on simulated data. Applying this method, ex vivo samples exhibited a small oxidative shift when exposed to sun filters alone, though this shift was much smaller than that imparted by UV irradiation. Given the need for investigative tools to further study the clinical impact of chemical sun filters in patients, the reported methodology may be applied to visualize chemical sun filters and measure oxidative stress in patients' skin.

  18. Deposition Uniformity of Coal Dust on Filters and Its Effect on the Accuracy of FTIR Analyses for Silica.

    Science.gov (United States)

    Miller, Arthur L; Drake, Pamela L; Murphy, Nathaniel C; Cauda, Emanuele G; LeBouf, Ryan F; Markevicius, Gediminas

    Miners are exposed to silica-bearing dust which can lead to silicosis, a potentially fatal lung disease. Currently, airborne silica is measured by collecting filter samples and sending them to a laboratory for analysis. Since this may take weeks, a field method is needed to inform decisions aimed at reducing exposures. This study investigates a field-portable Fourier transform infrared (FTIR) method for end-of-shift (EOS) measurement of silica on filter samples. Since the method entails localized analyses, spatial uniformity of dust deposition can affect accuracy and repeatability. The study, therefore, assesses the influence of radial deposition uniformity on the accuracy of the method. Using laboratory-generated Minusil and coal dusts and three different types of sampling systems, multiple sets of filter samples were prepared. All samples were collected in pairs to create parallel sets for training and validation. Silica was measured by FTIR at nine locations across the face of each filter and the data analyzed using a multiple regression analysis technique that compared various models for predicting silica mass on the filters using different numbers of "analysis shots." It was shown that deposition uniformity is independent of particle type (kaolin vs. silica), which suggests the role of aerodynamic separation is negligible. Results also reflected the correlation between the location and number of shots versus the predictive accuracy of the models. The coefficient of variation (CV) for the models when predicting mass of validation samples was 4%-51% depending on the number of points analyzed and the type of sampler used, which affected the uniformity of radial deposition on the filters. It was shown that using a single shot at the center of the filter yielded predictivity adequate for a field method, (93% return, CV approximately 15%) for samples collected with 3-piece cassettes.

  19. Evidence-Based Evaluation of Inferior Vena Cava Filter Complications Based on Filter Type

    Science.gov (United States)

    Deso, Steven E.; Idakoji, Ibrahim A.; Kuo, William T.

    2016-01-01

    Many inferior vena cava (IVC) filter types, along with their specific risks and complications, are not recognized. The purpose of this study was to evaluate the various FDA-approved IVC filter types to determine device-specific risks, as a way to help identify patients who may benefit from ongoing follow-up versus prompt filter retrieval. An evidence-based electronic search (FDA Premarket Notification, MEDLINE, FDA MAUDE) was performed to identify all IVC filter types and device-specific complications from 1980 to 2014. Twenty-three IVC filter types (14 retrievable, 9 permanent) were identified. The devices were categorized as follows: conical (n = 14), conical with umbrella (n = 1), conical with cylindrical element (n = 2), biconical with cylindrical element (n = 2), helical (n = 1), spiral (n = 1), and complex (n = 1). Purely conical filters were associated with the highest reported risks of penetration (90–100%). Filters with cylindrical or umbrella elements were associated with the highest reported risk of IVC thrombosis (30–50%). Conical Bard filters were associated with the highest reported risks of fracture (40%). The various FDA-approved IVC filter types were evaluated for device-specific complications based on best current evidence. This information can be used to guide and optimize clinical management in patients with indwelling IVC filters. PMID:27247477

  20. Model-Based Collaborative Filtering Analysis of Student Response Data: Machine-Learning Item Response Theory

    Science.gov (United States)

    Bergner, Yoav; Droschler, Stefan; Kortemeyer, Gerd; Rayyan, Saif; Seaton, Daniel; Pritchard, David E.

    2012-01-01

    We apply collaborative filtering (CF) to dichotomously scored student response data (right, wrong, or no interaction), finding optimal parameters for each student and item based on cross-validated prediction accuracy. The approach is naturally suited to comparing different models, both unidimensional and multidimensional in ability, including a…

  1. Higher safety and saving of filter material with multi-way sorption filters

    International Nuclear Information System (INIS)

    Ohlmeyer, M.; Benzel, M.

    1978-01-01

    The multi-way filter 'Nuclear Karlsruhe' satisfies the requirements of operational safety, high utilisation of the filter material and low pressure drop. An important factor contributing to increased operational safety is due to the fact that the nearly total utilisation of the filter material eliminates the need for optimisation weighing costs against safety. The reduction in filter material consumption reduces not only the direct procurement costs but also the costs of nuclear plants, is radioactive. This contributes in several respects towards a better protection of the environment. The MWS filter can also be used, and presents the same advantages, in non-nuclear plants. (orig.) [de

  2. Wavelet Filtering to Reduce Conservatism in Aeroservoelastic Robust Stability Margins

    Science.gov (United States)

    Brenner, Marty; Lind, Rick

    1998-01-01

    Wavelet analysis for filtering and system identification was used to improve the estimation of aeroservoelastic stability margins. The conservatism of the robust stability margins was reduced with parametric and nonparametric time-frequency analysis of flight data in the model validation process. Nonparametric wavelet processing of data was used to reduce the effects of external desirableness and unmodeled dynamics. Parametric estimates of modal stability were also extracted using the wavelet transform. Computation of robust stability margins for stability boundary prediction depends on uncertainty descriptions derived from the data for model validation. F-18 high Alpha Research Vehicle aeroservoelastic flight test data demonstrated improved robust stability prediction by extension of the stability boundary beyond the flight regime.

  3. Combination of Wiener filtering and singular value decomposition filtering for volume imaging PET

    International Nuclear Information System (INIS)

    Shao, L.; Lewitt, R.M.; Karp, J.S.

    1995-01-01

    Although the three-dimensional (3D) multi-slice rebinning (MSRB) algorithm in PET is fast and practical, and provides an accurate reconstruction, the MSRB image, in general, suffers from the noise amplified by its singular value decomposition (SVD) filtering operation in the axial direction. Their aim in this study is to combine the use of the Wiener filter (WF) with the SVD to decrease the noise and improve the image quality. The SVD filtering ''deconvolves'' the spatially variant axial response function while the WF suppresses the noise and reduces the blurring not modeled by the axial SVD filter but included in the system modulation transfer function. Therefore, the synthesis of these two techniques combines the advantages of both filters. The authors applied this approach to the volume imaging HEAD PENN-PET brain scanner with an axial extent of 256 mm. This combined filter was evaluated in terms of spatial resolution, image contrast, and signal-to-noise ratio with several phantoms, such as a cold sphere phantom and 3D brain phantom. Specifically, the authors studied both the SVD filter with an axial Wiener filter and the SVD filter with a 3D Wiener filter, and compared the filtered images to those from the 3D reprojection (3DRP) reconstruction algorithm. Their results indicate that the Wiener filter increases the signal-to-noise ratio and also improves the contrast. For the MSRB images of the 3D brain phantom, after 3D WF, both the Gray/White and Gray/Ventricle ratios were improved from 1.8 to 2.8 and 2.1 to 4.1, respectively. In addition, the image quality with the MSRB algorithm is close to that of the 3DRP algorithm with 3D WF applied to both image reconstructions

  4. A novel approach to achieving modular retrovirus clearance for a parvovirus filter.

    Science.gov (United States)

    Stuckey, Juliana; Strauss, Daniel; Venkiteshwaran, Adith; Gao, Jinxin; Luo, Wen; Quertinmont, Michelle; O'Donnell, Sean; Chen, Dayue

    2014-01-01

    Viral filtration is routinely incorporated into the downstream purification processes for the production of biologics produced in mammalian cell cultures (MCC) to remove potential viral contaminants. In recent years, the use of retentive filters designed for retaining parvovirus (~20 nm) has become an industry standard in a conscious effort to further improve product safety. Since retentive filters remove viruses primarily by the size exclusion mechanism, it is expected that filters designed for parvovirus removal can effectively clear larger viruses such as retroviruses (~100 nm). In an attempt to reduce the number of viral clearance studies, we have taken a novel approach to demonstrate the feasibility of claiming modular retrovirus clearance for Asahi Planova 20N filters. Porcine parvovirus (PPV) and xenotropic murine leukemia virus (XMuLV) were co-spiked into six different feedstreams and then subjected to laboratory scale Planova 20N filtration. Our results indicate that Planova 20N filters consistently retain retroviruses and no retrovirus has ever been detected in the filtrates even when significant PPV breakthrough is observed. Based on the data from multiple in-house viral validation studies and the results from the co-spiking experiments, we have successfully claimed a modular retrovirus clearance of greater than 6 log10 reduction factors (LRF) to support clinical trial applications in both USA and Europe. © 2013 American Institute of Chemical Engineers.

  5. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  6. Ensemble Kalman filter regularization using leave-one-out data cross-validation

    KAUST Repository

    Rayo Schiappacasse, Lautaro Jeró nimo; Hoteit, Ibrahim

    2012-01-01

    In this work, the classical leave-one-out cross-validation method for selecting a regularization parameter for the Tikhonov problem is implemented within the EnKF framework. Following the original concept, the regularization parameter is selected

  7. Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter

    KAUST Repository

    Luo, Xiaodong

    2011-12-01

    A robust ensemble filtering scheme based on the H∞ filtering theory is proposed. The optimal H∞ filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used in the Kalman filter. By design, the H∞ filter is more robust than the Kalman filter, in the sense that the estimation error in the H∞ filter in general has a finite growth rate with respect to the uncertainties in assimilation, except for a special case that corresponds to the Kalman filter. The original form of the H∞ filter contains global constraints in time, which may be inconvenient for sequential data assimilation problems. Therefore a variant is introduced that solves some time-local constraints instead, and hence it is called the time-local H∞ filter (TLHF). By analogy to the ensemble Kalman filter (EnKF), the concept of ensemble time-local H∞ filter (EnTLHF) is also proposed. The general form of the EnTLHF is outlined, and some of its special cases are discussed. In particular, it is shown that an EnKF with certain covariance inflation is essentially an EnTLHF. In this sense, the EnTLHF provides a general framework for conducting covariance inflation in the EnKF-based methods. Some numerical examples are used to assess the relative robustness of the TLHF–EnTLHF in comparison with the corresponding KF–EnKF method.

  8. OPTIMIZATION OF ADVANCED FILTER SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Newby; G.J. Bruck; M.A. Alvin; T.E. Lippert

    1998-04-30

    Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench

  9. Experimental and numerical study of the degradation of radioactive measurements in the filters of airborne radioactive surveillance systems

    International Nuclear Information System (INIS)

    Geryes, Tony

    2009-01-01

    The measurement of radioactivity in the filters of airborne radioactive surveillance systems is a major metrology difficulty due to the fact that the absorption of a radiation in the filter media and the mass of aerosols accumulated distort the nuclear counting response. This thesis focuses on the determination of correction factors for the radioactivity loss in the survey filters. In a first step, radioactive filters representing the atmospheric samples have been prepared using the nuclear test bench ICARE. The experimental study on reference filters provided a database to determine correction factors for various filtration conditions. The second part proposes a new numerical method developed to determine the correction factors. It consists of coupling GeoDict for particles filtration simulations and MCNPX simulations for a transport in matter. The good agreement obtained by comparing the numerical and experimental correction factors has permitted to validate the numerical model

  10. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  11. Lattice Boltzmann simulations for wall-flow dynamics in porous ceramic diesel particulate filters

    Science.gov (United States)

    Lee, Da Young; Lee, Gi Wook; Yoon, Kyu; Chun, Byoungjin; Jung, Hyun Wook

    2018-01-01

    Flows through porous filter walls of wall-flow diesel particulate filter are investigated using the lattice Boltzmann method (LBM). The microscopic model of the realistic filter wall is represented by randomly overlapped arrays of solid spheres. The LB simulation results are first validated by comparison to those from previous hydrodynamic theories and constitutive models for flows in porous media with simple regular and random solid-wall configurations. We demonstrate that the newly designed randomly overlapped array structures of porous walls allow reliable and accurate simulations for the porous wall-flow dynamics in a wide range of solid volume fractions from 0.01 to about 0.8, which is beyond the maximum random packing limit of 0.625. The permeable performance of porous media is scrutinized by changing the solid volume fraction and particle Reynolds number using Darcy's law and Forchheimer's extension in the laminar flow region.

  12. Sub-micron filter

    Science.gov (United States)

    Tepper, Frederick [Sanford, FL; Kaledin, Leonid [Port Orange, FL

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  13. Technical Note: Kinect V2 surface filtering during gantry motion for radiotherapy applications.

    Science.gov (United States)

    Nazir, Souha; Rihana, Sandy; Visvikis, Dimitris; Fayad, Hadi

    2018-04-01

    In radiotherapy, the Kinect V2 camera, has recently received a lot of attention concerning many clinical applications including patient positioning, respiratory motion tracking, and collision detection during the radiotherapy delivery phase. However, issues associated with such applications are related to some materials and surfaces reflections generating an offset in depth measurements especially during gantry motion. This phenomenon appears in particular when the collimator surface is observed by the camera; resulting in erroneous depth measurements, not only in Kinect surfaces itself, but also as a large peak when extracting a 1D respiratory signal from these data. In this paper, we proposed filtering techniques to reduce the noise effect in the Kinect-based 1D respiratory signal, using a trend removal filter, and in associated 2D surfaces, using a temporal median filter. Filtering process was validated using a phantom, in order to simulate a patient undergoing radiotherapy treatment while having the ground truth. Our results indicate a better correlation between the reference respiratory signal and its corresponding filtered signal (Correlation coefficient of 0.76) than that of the nonfiltered signal (Correlation coefficient of 0.13). Furthermore, surface filtering results show a decrease in the mean square distance error (85%) between the reference and the measured point clouds. This work shows a significant noise compensation and surface restitution after surface filtering and therefore a potential use of the Kinect V2 camera for different radiotherapy-based applications, such as respiratory tracking and collision detection. © 2018 American Association of Physicists in Medicine.

  14. Collaborative Filtering Recommendation Based on Trust Model with Fused Similar Factor

    Directory of Open Access Journals (Sweden)

    Ye Li

    2017-01-01

    Full Text Available Recommended system is beneficial to e-commerce sites, which provides customers with product information and recommendations; the recommendation system is currently widely used in many fields. In an era of information explosion, the key challenges of the recommender system is to obtain valid information from the tremendous amount of information and produce high quality recommendations. However, when facing the large mount of information, the traditional collaborative filtering algorithm usually obtains a high degree of sparseness, which ultimately lead to low accuracy recommendations. To tackle this issue, we propose a novel algorithm named Collaborative Filtering Recommendation Based on Trust Model with Fused Similar Factor, which is based on the trust model and is combined with the user similarity. The novel algorithm takes into account the degree of interest overlap between the two users and results in a superior performance to the recommendation based on Trust Model in criteria of Precision, Recall, Diversity and Coverage. Additionally, the proposed model can effectively improve the efficiency of collaborative filtering algorithm and achieve high performance.

  15. Superconducting Magnetometry for Cardiovascular Studies and AN Application of Adaptive Filtering.

    Science.gov (United States)

    Leifer, Mark Curtis

    Sensitive magnetic detectors utilizing Superconducting Quantum Interference Devices (SQUID's) have been developed and used for studying the cardiovascular system. The theory of magnetic detection of cardiac currents is discussed, and new experimental data supporting the validity of the theory is presented. Measurements on both humans and dogs, in both healthy and diseased states, are presented using the new technique, which is termed vector magnetocardiography. In the next section, a new type of superconducting magnetometer with a room temperature pickup is analyzed, and techniques for optimizing its sensitivity to low-frequency sub-microamp currents are presented. Performance of the actual device displays significantly improved sensitivity in this frequency range, and the ability to measure currents in intact, in vivo biological fibers. The final section reviews the theoretical operation of a digital self-optimizing filter, and presents a four-channel software implementation of the system. The application of the adaptive filter to enhancement of geomagnetic signals for earthquake forecasting is discussed, and the adaptive filter is shown to outperform existing techniques in suppressing noise from geomagnetic records.

  16. Improvement of the fringe analysis algorithm for wavelength scanning interferometry based on filter parameter optimization.

    Science.gov (United States)

    Zhang, Tao; Gao, Feng; Muhamedsalih, Hussam; Lou, Shan; Martin, Haydn; Jiang, Xiangqian

    2018-03-20

    The phase slope method which estimates height through fringe pattern frequency and the algorithm which estimates height through the fringe phase are the fringe analysis algorithms widely used in interferometry. Generally they both extract the phase information by filtering the signal in frequency domain after Fourier transform. Among the numerous papers in the literature about these algorithms, it is found that the design of the filter, which plays an important role, has never been discussed in detail. This paper focuses on the filter design in these algorithms for wavelength scanning interferometry (WSI), trying to optimize the parameters to acquire the optimal results. The spectral characteristics of the interference signal are analyzed first. The effective signal is found to be narrow-band (near single frequency), and the central frequency is calculated theoretically. Therefore, the position of the filter pass-band is determined. The width of the filter window is optimized with the simulation to balance the elimination of the noise and the ringing of the filter. Experimental validation of the approach is provided, and the results agree very well with the simulation. The experiment shows that accuracy can be improved by optimizing the filter design, especially when the signal quality, i.e., the signal noise ratio (SNR), is low. The proposed method also shows the potential of improving the immunity to the environmental noise by adapting the signal to acquire the optimal results through designing an adaptive filter once the signal SNR can be estimated accurately.

  17. Recirculating electric air filter

    Science.gov (United States)

    Bergman, W.

    1985-01-09

    An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  18. Pleasant/Unpleasant Filtering for Affective Image Retrieval Based on Cross-Correlation of EEG Features

    Directory of Open Access Journals (Sweden)

    Keranmu Xielifuguli

    2014-01-01

    Full Text Available People often make decisions based on sensitivity rather than rationality. In the field of biological information processing, methods are available for analyzing biological information directly based on electroencephalogram: EEG to determine the pleasant/unpleasant reactions of users. In this study, we propose a sensitivity filtering technique for discriminating preferences (pleasant/unpleasant for images using a sensitivity image filtering system based on EEG. Using a set of images retrieved by similarity retrieval, we perform the sensitivity-based pleasant/unpleasant classification of images based on the affective features extracted from images with the maximum entropy method: MEM. In the present study, the affective features comprised cross-correlation features obtained from EEGs produced when an individual observed an image. However, it is difficult to measure the EEG when a subject visualizes an unknown image. Thus, we propose a solution where a linear regression method based on canonical correlation is used to estimate the cross-correlation features from image features. Experiments were conducted to evaluate the validity of sensitivity filtering compared with image similarity retrieval methods based on image features. We found that sensitivity filtering using color correlograms was suitable for the classification of preferred images, while sensitivity filtering using local binary patterns was suitable for the classification of unpleasant images. Moreover, sensitivity filtering using local binary patterns for unpleasant images had a 90% success rate. Thus, we conclude that the proposed method is efficient for filtering unpleasant images.

  19. LCL filter design for three-phase two-level power factor correction using line impedance stabilization network

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Nymand, Morten

    2016-01-01

    This paper presents LCL filter design method for three-phase two-level power factor correction (PFC) using line impedance stabilization network (LISN). A straightforward LCL filter design along with variation in grid impedance is not simply achievable and inevitably lead to an iterative solution...... for filter. By introducing of fast power switches for PFC applications such as silicon-carbide, major current harmonics around the switching frequency drops in the region that LISN can actively provide well-defined impedance for measuring the harmonics (i.e. 9 kHz- 30MHz). Therefore, LISN can be replaced...... is derived using the current ripple behavior of converter-side inductor. The grid-side inductor is achieved as a function of LISN impedance to fulfill the grid regulation. To verify the analyses, an LCL filter is designed for a 5 kW SiC-based PFC. The simulation and experimental results support the validity...

  20. Kaon Filtering For CLAS Data

    International Nuclear Information System (INIS)

    McNabb, J.

    2001-01-01

    The analysis of data from CLAS is a multi-step process. After the detectors for a given running period have been calibrated, the data is processed in the so called pass-1 cooking. During the pass-1 cooking each event is reconstructed by the program a1c which finds particle tracks and computes momenta from the raw data. The results are then passed on to several data monitoring and filtering utilities. In CLAS software, a filter is a parameterless function which returns an integer indicating whether an event should be kept by that filter or not. There is a main filter program called g1-filter which controls several specific filters and outputs several files, one for each filter. These files may then be analyzed separately, allowing individuals interested in one reaction channel to work from smaller files than using the whole data set would require. There are several constraints on what the filter functions should do. Obviously, the filtered files should be as small as possible, however the filter should also not reject any events that might be used in the later analysis for which the filter was intended

  1. Improvement of active filter for HIMAC power sources

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Kubo, Hiroshi; Furuzeki, Shoichiro; Kanazawa, Toru

    1996-03-01

    For the power sources of the synchrotron electromagnets for the heavy particle beam cancer therapy apparatus HIMAC in National Institute of Radiological Science, in order to stabilize the taken-out beam, the ripple property as low as below 1 x 10{sup -6} is required. As for this electromagnet power sources, various devices were applied to lower ripples, and the required specifications have been satisfied. Also the beam spill is stable, but slight variation has been observed, therefore, by improving the performance of the active filter, the ripples were improved. The specifications of the electromagnet power sources and the whole constitution of the power source system are shown. In the HIMAC power sources, the means for having realized the low ripple performance so far are explained. Those are the absorption of the ineffective power generated from the power sources, the control of the ripples of common made due to the transducer thyristor, and the sure compensation of ripples by the control circuit for the power sources. By adding the band pass filters to the active filter, its characteristics were improved. As the result, 1200 Hz ripple component was reduced by 41 db, thus the sufficient effect was obtained. Hereafter, by the high sensitivity measurement of the current of electromagnets and the evaluation of magnetic fields, the validity will be evaluated. (K.I.)

  2. Design and Simulation of a T-Type Lymphocyte Cells Filter on a Microfluidic System

    Directory of Open Access Journals (Sweden)

    Daniel A. Quiroga T.

    2016-01-01

    Full Text Available This work consisted in designing and validating, by experimental computational simulation, a T-Lymphocites filtering system based on microfluidics for hiv virus detection. Material and methods: It was used AutoDesk® Inventor simulation tool was used with which the microflui­dic system design was performed. The filter system was tested by a computer simulation in the AutoDesk® Simulation cfd (computational fluid dynamics software, simulation tool in which different particles with different diameters (5 μm, 10 μm, 15 μm flow through the system to test. Results and conclusions: Results showed that this system allowed to pass the expected particles, however, it also was observed that it allows bigger particles than desired, for this reason it is neces­sary to keep on working on system perfectioning. Filtering system efficiency was of a 33.33 %.

  3. From Microwave Filter to Digital Filter and Back Again

    DEFF Research Database (Denmark)

    Dalby, Arne Brejning

    1989-01-01

    A new very simple state variable flow graph representation for interdigital transmission line bandpass filters is presented, which has led to two important results: 1) A new type of digital filter with properties, that surpass the properties of most other (all pole) digital filtertypes. 2) The st...

  4. Optimization of nonlinear, non-Gaussian Bayesian filtering for diagnosis and prognosis of monotonic degradation processes

    Science.gov (United States)

    Corbetta, Matteo; Sbarufatti, Claudio; Giglio, Marco; Todd, Michael D.

    2018-05-01

    The present work critically analyzes the probabilistic definition of dynamic state-space models subject to Bayesian filters used for monitoring and predicting monotonic degradation processes. The study focuses on the selection of the random process, often called process noise, which is a key perturbation source in the evolution equation of particle filtering. Despite the large number of applications of particle filtering predicting structural degradation, the adequacy of the picked process noise has not been investigated. This paper reviews existing process noise models that are typically embedded in particle filters dedicated to monitoring and predicting structural damage caused by fatigue, which is monotonic in nature. The analysis emphasizes that existing formulations of the process noise can jeopardize the performance of the filter in terms of state estimation and remaining life prediction (i.e., damage prognosis). This paper subsequently proposes an optimal and unbiased process noise model and a list of requirements that the stochastic model must satisfy to guarantee high prognostic performance. These requirements are useful for future and further implementations of particle filtering for monotonic system dynamics. The validity of the new process noise formulation is assessed against experimental fatigue crack growth data from a full-scale aeronautical structure using dedicated performance metrics.

  5. Filter apparatus

    International Nuclear Information System (INIS)

    Butterworth, D.J.

    1980-01-01

    This invention relates to liquid filters, precoated by replaceable powders, which are used in the production of ultra pure water required for steam generation of electricity. The filter elements are capable of being installed and removed by remote control so that they can be used in nuclear power reactors. (UK)

  6. Filtering and prediction

    CERN Document Server

    Fristedt, B; Krylov, N

    2007-01-01

    Filtering and prediction is about observing moving objects when the observations are corrupted by random errors. The main focus is then on filtering out the errors and extracting from the observations the most precise information about the object, which itself may or may not be moving in a somewhat random fashion. Next comes the prediction step where, using information about the past behavior of the object, one tries to predict its future path. The first three chapters of the book deal with discrete probability spaces, random variables, conditioning, Markov chains, and filtering of discrete Markov chains. The next three chapters deal with the more sophisticated notions of conditioning in nondiscrete situations, filtering of continuous-space Markov chains, and of Wiener process. Filtering and prediction of stationary sequences is discussed in the last two chapters. The authors believe that they have succeeded in presenting necessary ideas in an elementary manner without sacrificing the rigor too much. Such rig...

  7. The intractable cigarette 'filter problem'.

    Science.gov (United States)

    Harris, Bradford

    2011-05-01

    When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the 'filter problem'. These extensive filter research and development efforts suggest a phase of genuine optimism among cigarette designers that cigarette filters could be engineered to mitigate the health hazards of smoking. This paper explores the early history of cigarette filter research and development in order to elucidate why and when seemingly sincere filter engineering efforts devolved into manipulations in cigarette design to sustain cigarette marketing and mitigate consumers' concerns about the health consequences of smoking. Relevant word and phrase searches were conducted in the Legacy Tobacco Documents Library online database, Google Patents, and media and medical databases including ProQuest, JSTOR, Medline and PubMed. 13 tobacco industry documents were identified that track prominent developments involved in what the industry referred to as the 'filter problem'. These reveal a period of intense focus on the 'filter problem' that persisted from the mid-1950s to the mid-1960s, featuring collaborations between cigarette producers and large American chemical and textile companies to develop effective filters. In addition, the documents reveal how cigarette filter researchers' growing scientific knowledge of smoke chemistry led to increasing recognition that filters were unlikely to offer significant health protection. One of the primary concerns of cigarette producers was to design cigarette filters that could be economically incorporated into the massive scale of cigarette production. The synthetic plastic cellulose acetate

  8. Bowtie filters for dedicated breast CT: Analysis of bowtie filter material selection

    Energy Technology Data Exchange (ETDEWEB)

    Kontson, Kimberly, E-mail: Kimberly.Kontson@fda.hhs.gov; Jennings, Robert J. [Department of Bioengineering, University of Maryland, College Park, Maryland 20742 and Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)

    2015-09-15

    Purpose: For a given bowtie filter design, both the selection of material and the physical design control the energy fluence, and consequently the dose distribution, in the object. Using three previously described bowtie filter designs, the goal of this work is to demonstrate the effect that different materials have on the bowtie filter performance measures. Methods: Three bowtie filter designs that compensate for one or more aspects of the beam-modifying effects due to the differences in path length in a projection have been designed. The nature of the designs allows for their realization using a variety of materials. The designs were based on a phantom, 14 cm in diameter, composed of 40% fibroglandular and 60% adipose tissue. Bowtie design #1 is based on single material spectral matching and produces nearly uniform spectral shape for radiation incident upon the detector. Bowtie design #2 uses the idea of basis-material decomposition to produce the same spectral shape and intensity at the detector, using two different materials. With bowtie design #3, it is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Seven different materials were chosen to represent a range of chemical compositions and densities. After calculation of construction parameters for each bowtie filter design, a bowtie filter was created using each of these materials (assuming reasonable construction parameters were obtained), resulting in a total of 26 bowtie filters modeled analytically and in the PENELOPE Monte Carlo simulation environment. Using the analytical model of each bowtie filter, design profiles were obtained and energy fluence as a function of fan-angle was calculated. Projection images with and without each bowtie filter design were also generated using PENELOPE and reconstructed using FBP. Parameters such as dose distribution, noise uniformity

  9. Bowtie filters for dedicated breast CT: Analysis of bowtie filter material selection

    International Nuclear Information System (INIS)

    Kontson, Kimberly; Jennings, Robert J.

    2015-01-01

    Purpose: For a given bowtie filter design, both the selection of material and the physical design control the energy fluence, and consequently the dose distribution, in the object. Using three previously described bowtie filter designs, the goal of this work is to demonstrate the effect that different materials have on the bowtie filter performance measures. Methods: Three bowtie filter designs that compensate for one or more aspects of the beam-modifying effects due to the differences in path length in a projection have been designed. The nature of the designs allows for their realization using a variety of materials. The designs were based on a phantom, 14 cm in diameter, composed of 40% fibroglandular and 60% adipose tissue. Bowtie design #1 is based on single material spectral matching and produces nearly uniform spectral shape for radiation incident upon the detector. Bowtie design #2 uses the idea of basis-material decomposition to produce the same spectral shape and intensity at the detector, using two different materials. With bowtie design #3, it is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Seven different materials were chosen to represent a range of chemical compositions and densities. After calculation of construction parameters for each bowtie filter design, a bowtie filter was created using each of these materials (assuming reasonable construction parameters were obtained), resulting in a total of 26 bowtie filters modeled analytically and in the PENELOPE Monte Carlo simulation environment. Using the analytical model of each bowtie filter, design profiles were obtained and energy fluence as a function of fan-angle was calculated. Projection images with and without each bowtie filter design were also generated using PENELOPE and reconstructed using FBP. Parameters such as dose distribution, noise uniformity

  10. Instantaneous Attitude Determination Based on Original Multi-antenna Observations Using Adaptively Robust Kalman Filtering

    Directory of Open Access Journals (Sweden)

    GAN Yu

    2015-09-01

    Full Text Available Attitude determination directly by carrier phase observation makes optimal use of observation and attitude constraints. The phase models based on misalignment angle and multiplicative quaternion error are derived. The state models for attitude estimation with and without external angular rate sensors are both erected. The attitude errors are estimated by adaptively robust filtering, in which the adaptive factors of ambiguity and attitude error are decided respectively following the idea of multi adaptive factor filtering. The factor of attitude is determined by a three-section function containing Ratio. Adaptively robust filtering makes the best use of constraint and historical information, fusing them in the calculation of float solution. As the accuracy of float solution and the structure of covariance matrix are improved greatly, the fix solution can be searched efficiently using LAMBDA (least-squares ambiguity decorrelation adjustment method merely, perfectly fulfilling the real-time requirement. Field test of a ship-based three-antenna attitude system is used to validate the proposed method. It is showed that direct attitude determination based on adaptively robust filtering has obvious advantages in efficiency and reliability.

  11. Multidimensional student skills with collaborative filtering

    Science.gov (United States)

    Bergner, Yoav; Rayyan, Saif; Seaton, Daniel; Pritchard, David E.

    2013-01-01

    Despite the fact that a physics course typically culminates in one final grade for the student, many instructors and researchers believe that there are multiple skills that students acquire to achieve mastery. Assessment validation and data analysis in general may thus benefit from extension to multidimensional ability. This paper introduces an approach for model determination and dimensionality analysis using collaborative filtering (CF), which is related to factor analysis and item response theory (IRT). Model selection is guided by machine learning perspectives, seeking to maximize the accuracy in predicting which students will answer which items correctly. We apply the CF to response data for the Mechanics Baseline Test and combine the results with prior analysis using unidimensional IRT.

  12. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  13. Rotationally invariant correlation filtering

    International Nuclear Information System (INIS)

    Schils, G.F.; Sweeney, D.W.

    1985-01-01

    A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

  14. Monolithic Integrated Ceramic Waveguide Filters

    OpenAIRE

    Hunter, IC; Sandhu, MY

    2014-01-01

    Design techniques for a new class of integrated monolithic high permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled TEM filters with the same unloaded Q-Factor. Designs for both chebyshev and asymmetric generalized chebyshev filter are presented, with experimental results for an 1800 MHz chebyshev filter showing excellent agreement with theory.

  15. Shifted-modified Chebyshev filters

    OpenAIRE

    ŞENGÜL, Metin

    2013-01-01

    This paper introduces a new type of filter approximation method that utilizes shifted-modified Chebyshev filters. Construction of the new filters involves the use of shifted-modified Chebyshev polynomials that are formed using the roots of conventional Chebyshev polynomials. The study also includes 2 tables containing the shifted-modified Chebyshev polynomials and the normalized element values for the low-pass prototype filters up to degree 6. The transducer power gain, group dela...

  16. Examination of cryogenic filters for multistage RF filtering in ultralow temperature experiments

    Science.gov (United States)

    Zavyalov, V. V.; Chernyaev, S. A.; Shein, K. V.; Shukaleva, A. G.; Arutyunov, K. Yu

    2018-03-01

    Cryo-filters are essential while studying electronic properties of nanoscale structures at very low temperatures. In this report we present the simple measuring methodology and experimental impedance characteristics of customized lumped filters cooled down to 4.2K in the 10 Hz-500 MHz frequency range. In particular, we tested the home-made permalloy-core RL filters, the MurataTMChip Ferrite Bead filter, and the ToshibaTMAmobeadsTMcores. We use the high-frequency generalization of four-terminal sensing method to account for the wiring retardation effects, which are important when working with ultralow temperature systems.

  17. Robust Object Tracking Using Valid Fragments Selection.

    Science.gov (United States)

    Zheng, Jin; Li, Bo; Tian, Peng; Luo, Gang

    Local features are widely used in visual tracking to improve robustness in cases of partial occlusion, deformation and rotation. This paper proposes a local fragment-based object tracking algorithm. Unlike many existing fragment-based algorithms that allocate the weights to each fragment, this method firstly defines discrimination and uniqueness for local fragment, and builds an automatic pre-selection of useful fragments for tracking. Then, a Harris-SIFT filter is used to choose the current valid fragments, excluding occluded or highly deformed fragments. Based on those valid fragments, fragment-based color histogram provides a structured and effective description for the object. Finally, the object is tracked using a valid fragment template combining the displacement constraint and similarity of each valid fragment. The object template is updated by fusing feature similarity and valid fragments, which is scale-adaptive and robust to partial occlusion. The experimental results show that the proposed algorithm is accurate and robust in challenging scenarios.

  18. Flexible time-varying filter banks

    Science.gov (United States)

    Tuncer, Temel E.; Nguyen, Truong Q.

    1993-09-01

    Linear phase maximally flat FIR Butterworth filter approximations are discussed and a new filter design method is introduced. This variable cutoff filter design method uses the cosine modulated versions of a prototype filter. The design procedure is simple and different variants of this procedure can be used to obtain close to optimum linear phase filters. Using this method, flexible time-varying filter banks with good reconstruction error are introduced. These types of oversampled filter banks have small magnitude error which can be easily controlled by the appropriate choice of modulation frequency. This error can be further decreased by magnitude equalization without increasing the computational complexity considerably. Two dimensional design examples are also given.

  19. Design and implementation of predictive filtering system for current reference generation of active power filter

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Tomislav; Milun, Stanko; Petrovic, Goran [FESB University of Split, Faculty of Electrical Engineering, Machine Engineering and Naval Architecture, R. Boskovica bb, 21000, Split (Croatia)

    2007-02-15

    The shunt active power filters are used to attenuate the harmonic currents in power systems by injecting equal but opposite compensating currents. Successful control of the active filters requires an accurate current reference. In this paper the current reference determination based on predictive filtering structure is presented. Current reference was obtained by taking the difference of load current and its fundamental harmonic. For fundamental harmonic determination with no time delay a combination of digital predictive filter and low pass filter is used. The proposed method was implemented on a laboratory prototype of a three-phase active power filter. The algorithm for current reference determination was adapted and implemented on DSP controller. Simulation and experimental results show that the active power filter with implemented predictive filtering structure gives satisfactory performance in power system harmonic attenuation. (author)

  20. Grid impedance detection via excitation of LCL-filter resonance

    DEFF Research Database (Denmark)

    Liserre, Marco; Blaabjerg, Frede; Teodorescu, Remus

    2005-01-01

    Inverters adopted in distributed power generation, active filter and UPS are often connected to the grid through an LCL-fiIter. The impedance of the LCL-fiIter has a typical frequency spectrum with a resonance peak. Hence the LCL-fiIter has to be damped in order to avoid instability. However...... the resonance of the LCL-fiIter can be also excited in a controlled way in order to individuate the resonance frequency in the spectrum (using for example the FFn. This paper proposes to use a controlled excitation to measure the grid impedance, since this one influences also the resonance frequency. This paper...... will address some possible limits, some solutions and some implementation issues (e.g. how to obtain a controlled resonance in the filter without damaging the system) in order to use the resonant peak for grid impedance detection. The analysis is validated both by simulations and experimental results....

  1. Design and control of LCL-filter with active damping for Active Power Filter

    DEFF Research Database (Denmark)

    Zeng, Guohong; Rasmussen, Tonny Wederberg; Ma, L

    2010-01-01

    of LCL-filter for APF is introduced, which is aimed for simplified the implementation. To suppress the resonance that may be excited in the system, which brings in stability problems, an active damping control strategy using the current feed-back of the filter capacitor is adopted. By selecting two equal......In the application of shunt Active Power Filter (APF) to compensate nonlinear load's harmonic, reactive and negative sequence current, it is more effective to use a LCL-filter than an L-filter as an interface between the Voltage Source Converter (VSC) and grid. In this paper, a designing procedure...... or similar inductances, the filter designing become more simple and effective, meanwhile the capacitance requirement is minimized. A pole-zero automatic cancellation phenomenon is discussed in this paper, which can be applied to simplify the current regulator designing. The tuning method is presented, based...

  2. Digital Filters for Low Frequency Equalization

    DEFF Research Database (Denmark)

    Tyril, Marni; Abildgaard, J.; Rubak, Per

    2001-01-01

    Digital filters with high resolution in the low-frequency range are studied. Specifically, for a given computational power, traditional IIR filters are compared with warped FIR filters, warped IIR filters, and modified warped FIR filters termed warped individual z FIR filters (WizFIR). The results...

  3. Vectorization of linear discrete filtering algorithms

    Science.gov (United States)

    Schiess, J. R.

    1977-01-01

    Linear filters, including the conventional Kalman filter and versions of square root filters devised by Potter and Carlson, are studied for potential application on streaming computers. The square root filters are known to maintain a positive definite covariance matrix in cases in which the Kalman filter diverges due to ill-conditioning of the matrix. Vectorization of the filters is discussed, and comparisons are made of the number of operations and storage locations required by each filter. The Carlson filter is shown to be the most efficient of the filters on the Control Data STAR-100 computer.

  4. Hydrodynamic calculation of a filter sand bed type used in the containment venting systems

    International Nuclear Information System (INIS)

    Cuevas V, D.; Sainz M, E.; Ortiz V, J.

    2015-09-01

    The filtered venting of the containment has been adopted in European countries to mitigate the consequences of excess pressure containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter on the same path is placed, so that various types of filters are used to trap the fission products. The venting filters of the containment currently installed use different filtration technologies that involve more than one medium. Those using water as the first stage of filtration are called wet systems and are equipped with additional steps to remove water drops and fine aerosols emissions. And even they may also be equipped with an element containing certain absorption means for the filtration of gaseous iodine species. Other designs based on filtration of deep bed as the primary retention step; called dry filters, use filtration media of metal fiber, ceramic or sand to trap aerosols. This paper evaluates the hydraulic characteristics of the filter sand bed type designed by EDF as a candidate to be installed in the containment of BWR Mark II (type of primary containment of the nuclear power plant of Laguna Verde). The evaluation of filter sand bed type was performed using the software package of open source OpenFOAM. Models of each zone of the filtered device were generated and through a series of parametric calculations of computational fluid mechanics relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow rate and pressure fields and speed at different operating conditions. On the other hand, the model validation of the sand bed filter when comparing the results of experimental tests on a sand column of PITEAS program (1985-1986) against OpenFOAM simulation was realized. The results are very close to those obtained experimentally. (Author)

  5. Device for filtering gaseous media

    International Nuclear Information System (INIS)

    Benzel, M.

    1978-01-01

    The air filter system for gaseous radioactive substances consists of a vertical chamber with filter material (charcoal, e.g. impregnated). On one side of the chamber there is an inlet compartment and an outlet compartment. On the other side a guiding compartment turns the gas flow coming from the natural-air side through the lower part of filter chamber to the upper part of the filter. The gas flow leaves the upper part through the outlet conpartment as cleaned-air flow. The filter material may be filled into the chamber from above and drawn off below. For better utilization of the filter material the filter chamber is separated by means of a wall between the inlet and outlet compartment. This partition wall consist of two sheets arranged one above the other provided with slots which may be superposed in alignment. In this case filter material is tickling from the upper part of the chamber into the lower part avoiding to form a crater in the filter bed. (DG) [de

  6. Operating regimes of signaling cycles: statics, dynamics, and noise filtering.

    Directory of Open Access Journals (Sweden)

    Carlos Gomez-Uribe

    2007-12-01

    Full Text Available A ubiquitous building block of signaling pathways is a cycle of covalent modification (e.g., phosphorylation and dephosphorylation in MAPK cascades. Our paper explores the kind of information processing and filtering that can be accomplished by this simple biochemical circuit. Signaling cycles are particularly known for exhibiting a highly sigmoidal (ultrasensitive input-output characteristic in a certain steady-state regime. Here, we systematically study the cycle's steady-state behavior and its response to time-varying stimuli. We demonstrate that the cycle can actually operate in four different regimes, each with its specific input-output characteristics. These results are obtained using the total quasi-steady-state approximation, which is more generally valid than the typically used Michaelis-Menten approximation for enzymatic reactions. We invoke experimental data that suggest the possibility of signaling cycles operating in one of the new regimes. We then consider the cycle's dynamic behavior, which has so far been relatively neglected. We demonstrate that the intrinsic architecture of the cycles makes them act--in all four regimes--as tunable low-pass filters, filtering out high-frequency fluctuations or noise in signals and environmental cues. Moreover, the cutoff frequency can be adjusted by the cell. Numerical simulations show that our analytical results hold well even for noise of large amplitude. We suggest that noise filtering and tunability make signaling cycles versatile components of more elaborate cell-signaling pathways.

  7. DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC.

    Science.gov (United States)

    The Filter Flow Technology, Inc. (FFT) Colloid Polishing Filter Method (CPFM) was tested as a transportable, trailer mounted, system that uses sorption and chemical complexing phenomena to remove heavy metals and nontritium radionuclides from water. Contaminated waters can be pro...

  8. Hysteresis Control for Shunt Active Power Filter under Unbalanced Three-Phase Load Conditions

    Directory of Open Access Journals (Sweden)

    Z. Chelli

    2015-01-01

    Full Text Available This paper focuses on a four-wire shunt active power filter (APF control scheme proposed to improve the performance of the APF. This filter is used to compensate harmonic distortion in three-phase four-wire systems. Several harmonic suppression techniques have been widely proposed and applied to minimize harmonic effects. The proposed control scheme can compensate harmonics and reactive power of the nonlinear loads simultaneously. This approach is compared to the conventional shunt APF reference compensation strategy. The developed algorithm is validated by simulation tests using MATLAB Simulink. The obtained results have demonstrated the effectiveness of the proposed scheme and confirmed the theoretical developments for balanced and unbalanced nonlinear loads.

  9. Hydrodynamics of microbial filter feeding.

    Science.gov (United States)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia; Walther, Jens H; Kiørboe, Thomas; Andersen, Anders

    2017-08-29

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet), something notoriously difficult to visualize but sporadically observed in the related choanocytes (sponges). A CFD model with a flagellar vane correctly predicts the filtration rate of D. grandis , and using a simple model we can account for the filtration rates of other microbial filter feeders. We finally predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling.

  10. Ceramic fiber reinforced filter

    Science.gov (United States)

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  11. Robust Event-Triggered Energy-to-Peak Filtering for Polytopic Uncertain Systems over Lossy Network with Quantized Measurements

    Directory of Open Access Journals (Sweden)

    Jidong Wang

    2016-01-01

    Full Text Available The event-triggered energy-to-peak filtering for polytopic discrete-time linear systems is studied with the consideration of lossy network and quantization error. Because of the communication imperfections from the packet dropout of lossy link, the event-triggered condition used to determine the data release instant at the event generator (EG can not be directly applied to update the filter input at the zero order holder (ZOH when performing filter performance analysis and synthesis. In order to balance such nonuniform time series between the triggered instant of EG and the updated instant of ZOH, two event-triggered conditions are defined, respectively, whereafter a worst-case bound on the number of consecutive packet losses of the transmitted data from EG is given, which marginally guarantees the effectiveness of the filter that will be designed based on the event-triggered updating condition of ZOH. Then, the filter performance analysis conditions are obtained under the assumption that the maximum number of packet losses is allowable for the worst-case bound. In what follows, a two-stage LMI-based alternative optimization approach is proposed to separately design the filter, which reduces the conservatism of the traditional linearization method of filter analysis conditions. Subsequently a codesign algorithm is developed to determine the communication and filter parameters simultaneously. Finally, an illustrative example is provided to verify the validity of the obtained results.

  12. A Pilot RCT of an Internet Intervention to Reduce the Risk of Alcohol-Exposed Pregnancy.

    Science.gov (United States)

    Ingersoll, Karen; Frederick, Christina; MacDonnell, Kirsten; Ritterband, Lee; Lord, Holly; Jones, Brogan; Truwit, Lauren

    2018-06-01

    Preventing alcohol-exposed pregnancies (AEPs) could reduce the incidence of fetal alcohol spectrum disorders. Previous face-to-face interventions significantly reduced risk for AEP, but a scalable intervention is needed to reach more women at risk. This study compared a 6 Core automated, interactive, and tailored Internet intervention, the Contraception and Alcohol Risk Reduction Internet Intervention (CARRII), to a static patient education (PE) website for its effect on AEP risk. Participants were recruited online to a pilot randomized clinical trial (RCT) with baseline, 9 weeks posttreatment, and 6-month (6-M) follow-up assessments. Seventy-one women completed online questionnaires and telephone interviews and were randomized to CARRII (n = 36) or PE (n = 35). Primary outcomes were rates of risky drinking, unprotected sex episodes, and AEP risk, collected from online prospective diaries. CARRII participants showed significant reductions in rate of unprotected sex from pretreatment (88.9%) to posttreatment (70.6%) (p < 0.04) and to 6-M follow-up (51.5%) (p = 0.001); rate of risky drinking from pretreatment (75.0%) to posttreatment (50.0%) (p < 0.02), but insignificant change from pretreatment to 6-M follow-up (57.6%) (p < 0.09); and rate of AEP risk from pretreatment (66.7%) to posttreatment (32.4%) (p = 0.001) and to 6-M follow-up (30.3%) (p = 0.005). PE participants demonstrated no significant changes on all 3 variables across all time points. Intent-to-treat group-by-time tests were not significant, but power was limited by missing diaries. Over 72% of CARRII participants completed all 6 Cores. Exploratory analyses suggest that higher program utilization is related to change. These data show that CARRII was acceptable, feasible, promising to reduce AEP risk, and merits further testing in a fully powered RCT. Copyright © 2018 by the Research Society on Alcoholism.

  13. An Improved Strong Tracking Cubature Kalman Filter for GPS/INS Integrated Navigation Systems.

    Science.gov (United States)

    Feng, Kaiqiang; Li, Jie; Zhang, Xi; Zhang, Xiaoming; Shen, Chong; Cao, Huiliang; Yang, Yanyu; Liu, Jun

    2018-06-12

    The cubature Kalman filter (CKF) is widely used in the application of GPS/INS integrated navigation systems. However, its performance may decline in accuracy and even diverge in the presence of process uncertainties. To solve the problem, a new algorithm named improved strong tracking seventh-degree spherical simplex-radial cubature Kalman filter (IST-7thSSRCKF) is proposed in this paper. In the proposed algorithm, the effect of process uncertainty is mitigated by using the improved strong tracking Kalman filter technique, in which the hypothesis testing method is adopted to identify the process uncertainty and the prior state estimate covariance in the CKF is further modified online according to the change in vehicle dynamics. In addition, a new seventh-degree spherical simplex-radial rule is employed to further improve the estimation accuracy of the strong tracking cubature Kalman filter. In this way, the proposed comprehensive algorithm integrates the advantage of 7thSSRCKF’s high accuracy and strong tracking filter’s strong robustness against process uncertainties. The GPS/INS integrated navigation problem with significant dynamic model errors is utilized to validate the performance of proposed IST-7thSSRCKF. Results demonstrate that the improved strong tracking cubature Kalman filter can achieve higher accuracy than the existing CKF and ST-CKF, and is more robust for the GPS/INS integrated navigation system.

  14. Multiple Bloch surface waves in visible region of light at the interfaces between rugate filter/rugate filter and rugate filter/dielectric slab/rugate filter

    Science.gov (United States)

    Ullah Manzoor, Habib; Manzoor, Tareq; Hussain, Masroor; Manzoor, Sanaullah; Nazar, Kashif

    2018-04-01

    Surface electromagnetic waves are the solution of Maxwell’s frequency domain equations at the interface of two dissimilar materials. In this article, two canonical boundary-value problems have been formulated to analyze the multiplicity of electromagnetic surface waves at the interface between two dissimilar materials in the visible region of light. In the first problem, the interface between two semi-infinite rugate filters having symmetric refractive index profiles is considered and in the second problem, to enhance the multiplicity of surface electromagnetic waves, a homogeneous dielectric slab of 400 nm is included between two semi-infinite symmetric rugate filters. Numerical results show that multiple Bloch surface waves of different phase speeds, different polarization states, different degrees of localization and different field profiles are propagated at the interface between two semi-infinite rugate filters. Having two interfaces when a homogeneous dielectric layer is placed between two semi-infinite rugate filters has increased the multiplicity of electromagnetic surface waves.

  15. SOGI-based capacitor voltage feedback active damping in LCL-filtered grid converters

    DEFF Research Database (Denmark)

    Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    The capacitor voltage feedback active damping control is an attractive way to suppress LCL-filter resonance especially for the systems where the capacitor voltage is used for grid synchronization, since no extra sensors are added. The derivative is the core of the capacitor voltage feedback active...... derivative is more suited for capacitor voltage feedback active damping control. Experimental results validate the effectiveness of the proposed method....

  16. Active RC filter based implementation analysis part of two channel hybrid filter bank

    Directory of Open Access Journals (Sweden)

    Stojanović Vidosav

    2014-01-01

    Full Text Available In the present paper, a new design method for continuous-time powersymmetric active RC filters for Hybrid Filter Bank (HFB is proposed. Some theoretical properties of continious-time power-symmetric filters bank in a more general perspective are studied. This includes the derivation of a new general analytical form, and a study of poles and zeros locations in s-plane. In the proposed design method the analytic solution of filter coefficients is solved in sdomain using only one nonlinear equation Finally, the proposed approximation is compared to standard approximations. It was shown that attenuation and group delay characteristic of the proposed filter lie between Butterworth and elliptic characteristics. [Projekat Ministarstva nauke Republike Srbije, br. 32009TR

  17. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  18. Ventilation filters as sources of air pollution – Processes occurring on surfaces of used filters

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Halás, Oto; Clausen, Geo

    2004-01-01

    Ozone concentrations were monitored upstream and downstream of used filter samples following 24hours of ventilation with ozone- filtered air. The ozone concentration in the air upstream of the filters was maintained at ~75 ppb while the concentration downstream of the filters was initially betwee...

  19. No influence of positive emotion on orbitofrontal reality filtering: relevance for confabulation

    Directory of Open Access Journals (Sweden)

    Maria Chiara eLiverani

    2016-05-01

    Full Text Available Orbitofrontal reality filtering is a mechanism that allows us to keep thought and behavior in phase with reality. Its failure induces reality confusion with confabulation and disorientation. Confabulations have been claimed to have a positive emotional bias, suggesting that they emanate from a tendency to embellish the situation of a handicap. Here we tested the influence of positive emotion on orbitofrontal reality filtering in healthy subjects using a paradigm validated in reality confusing patients and with a known electrophysiological signature, a frontal positivity at 200-400 ms after memory evocation. Subjects made two continuous recognition tasks (two runs, composed of the same set of neutral and positive pictures, but arranged in different order. In both runs, participants had to indicate pictures repetitions within, and only within, the ongoing run. The first run measures learning and recognition. The second run, where all items are familiar, requires orbitofrontal reality filtering to avoid false positive responses. High-density evoked potentials were recorded from nineteen healthy subjects during completion of the task. Performance was more accurate and faster on neutral than positive pictures in both runs and all conditions. Evoked potential correlates of emotion and reality filtering occurred at 260-350 ms but dissociated in terms of amplitudes and topography. In both runs, positive stimuli evoked a more negative frontal potential than neutral ones. In the second run, the frontal positivity characteristic of reality filtering was separately, and to the same degree, expressed for positive and neutral stimuli. We conclude that orbitofrontal reality filtering, the ability to place oneself correctly in time and space, is not influenced by emotional positivity of the processed material.

  20. Speckle Filtering of GF-3 Polarimetric SAR Data with Joint Restriction Principle.

    Science.gov (United States)

    Xie, Jinwei; Li, Zhenfang; Zhou, Chaowei; Fang, Yuyuan; Zhang, Qingjun

    2018-05-12

    Polarimetric SAR (PolSAR) scattering characteristics of imagery are always obtained from the second order moments estimation of multi-polarization data, that is, the estimation of covariance or coherency matrices. Due to the extra-paths that signal reflected from separate scatterers within the resolution cell has to travel, speckle noise always exists in SAR images and has a severe impact on the scattering performance, especially on single look complex images. In order to achieve high accuracy in estimating covariance or coherency matrices, three aspects are taken into consideration: (1) the edges and texture of the scene are distinct after speckle filtering; (2) the statistical characteristic should be similar to the object pixel; and (3) the polarimetric scattering signature should be preserved, in addition to speckle reduction. In this paper, a joint restriction principle is proposed to meet the requirement. Three different restriction principles are introduced to the processing of speckle filtering. First, a new template, which is more suitable for the point or line targets, is designed to ensure the morphological consistency. Then, the extent sigma filter is used to restrict the pixels in the template aforementioned to have an identical statistic characteristic. At last, a polarimetric similarity factor is applied to the same pixels above, to guarantee the similar polarimetric features amongst the optional pixels. This processing procedure is named as speckle filtering with joint restriction principle and the approach is applied to GF-3 polarimetric SAR data acquired in San Francisco, CA, USA. Its effectiveness of keeping the image sharpness and preserving the scattering mechanism as well as speckle reduction is validated by the comparison with boxcar filters and refined Lee filter.

  1. Spatial filtering with photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maigyte, Lina [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Staliunas, Kestutis [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona 08010 (Spain)

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  2. Design of an international multicentre RCT on group schema therapy for borderline personality disorder.

    Science.gov (United States)

    Wetzelaer, Pim; Farrell, Joan; Evers, Silvia M A A; Jacob, Gitta A; Lee, Christopher W; Brand, Odette; van Breukelen, Gerard; Fassbinder, Eva; Fretwell, Heather; Harper, R Patrick; Lavender, Anna; Lockwood, George; Malogiannis, Ioannis A; Schweiger, Ulrich; Startup, Helen; Stevenson, Teresa; Zarbock, Gerhard; Arntz, Arnoud

    2014-11-18

    Borderline personality disorder (BPD) is a severe and highly prevalent mental disorder. Schema therapy (ST) has been found effective in the treatment of BPD and is commonly delivered through an individual format. A group format (group schema therapy, GST) has also been developed. GST has been found to speed up and amplify the treatment effects found for individual ST. Delivery in a group format may lead to improved cost-effectiveness. An important question is how GST compares to treatment as usual (TAU) and what format for delivery of schema therapy (format A; intensive group therapy only, or format B; a combination of group and individual therapy) produces the best outcomes. An international, multicentre randomized controlled trial (RCT) will be conducted with a minimum of fourteen participating centres. Each centre will recruit multiple cohorts of at least sixteen patients. GST formats as well as the orders in which they are delivered to successive cohorts will be balanced. Within countries that contribute an uneven number of sites, the orders of GST formats will be balanced within a difference of one. The RCT is designed to include a minimum of 448 patients with BPD. The primary clinical outcome measure will be BPD severity. Secondary clinical outcome measures will include measures of BPD and general psychiatric symptoms, schemas and schema modes, social functioning and quality of life. Furthermore, an economic evaluation that consists of cost-effectiveness and cost-utility analyses will be performed using a societal perspective. Lastly, additional investigations will be carried out that include an assessment of the integrity of GST, a qualitative study on patients' and therapists' experiences with GST, and studies on variables that might influence the effectiveness of GST. This trial will compare GST to TAU for patients with BPD as well as two different formats for the delivery of GST. By combining an evaluation of clinical effectiveness, an economic evaluation

  3. Design and Analysis of Robust Active Damping for LCL Filters using Digital Notch Filters

    DEFF Research Database (Denmark)

    Yao, Wenli; Yang, Yongheng; Zhang, Xiaobin

    2017-01-01

    Resonant poles of LCL filters may challenge the entire system stability especially in digital-controlled Pulse Width Modulation (PWM) inverters. In order to tackle the resonance issues, many active damping solutions have been reported. For instance, a notch filter can be employed to damp the reso......Resonant poles of LCL filters may challenge the entire system stability especially in digital-controlled Pulse Width Modulation (PWM) inverters. In order to tackle the resonance issues, many active damping solutions have been reported. For instance, a notch filter can be employed to damp...... the resonance, where the notch frequency should be aligned exactly to the resonant frequency of the LCL filter. However, parameter variations of the LCL filter as well as the time delay appearing in digital control systems will induce resonance drifting, and thus break this alignment, possibly deteriorating...... the original damping. In this paper, the effectiveness of the notch filter based active damping is firstly explored, considering the drifts of the resonant frequency. It is revealed that, when the resonant frequency drifts away from its nominal value, the phase lead or lag introduced by the notch filter may...

  4. FULL SCALE REGENERABLE HEPA FILTER DESIGN USING SINTERED METAL FILTER ELEMENTS

    International Nuclear Information System (INIS)

    Gil Ramos; Kenneth Rubow; Ronald Sekellick

    2002-01-01

    A Department of Energy funded contract involved the development of porous metal as a HEPA filter, and the subsequent design of a full-scale regenerable HEPA filtration system (RHFS). This RHFS could replace the glass fiber HEPA filters currently being used on the high level waste (HLW) tank ventilation system with a system that would be moisture tolerant, durable, and cleanable in place. The origins of the contract are a 1996 investigation at the Savannah River Technology Center (SRTC) regarding the use of porous metal as a HEPA filter material. This contract was divided into Phases I, IIA and IIB. Phase I of the contract evaluated simple filter cylinders in a simulated High Level Waste (HLW) environment and the ability to clean and regenerate the filter media after fouling. Upon the successful completion of Phase I, Phase IIA was conducted, which included lab scale prototype testing and design of a full-scale system. The work completed under Phase IIA included development of a full-scale system design, development of a filter media meeting the HEPA filtration efficiency that would also be regenerable using prescribed cleaning procedures, and the testing of a single element system prototype at Savannah River. All contract objectives were met. The filter media selected was a nickel material already under development at Mott, which met the HEPA filtration efficiency standard. The Mott nickel media met and exceeded the HEPA requirement, providing 99.99% removal against a requirement of 99.97%. Double open-ended elements of this media were provided to the Savannah River Test Center for HLW simulation testing in the single element prototype filter. These elements performed well and further demonstrated the practicality of a metallic media regenerable HEPA filter system. An evaluation of the manufacturing method on many elements demonstrated the reproducibility to meet the HEPA filtration requirement. The full-scale design of the Mott RHFS incorporated several important

  5. Filter Paper: Solution to High Self-Attenuation Corrections in HEPA Filter Measurements

    International Nuclear Information System (INIS)

    Oberer, R.B.; Harold, N.B.; Gunn, C.A.; Brummett, M.; Chaing, L.G.

    2005-01-01

    An 8 by 8 by 6 inch High Efficiency Particulate Air (HEPA) filter was measured as part of a uranium holdup survey in June of 2005 as it has been routinely measured every two months since 1998. Although the survey relies on gross gamma count measurements, this was one of a few measurements that had been converted to a quantitative measurement in 1998. The measurement was analyzed using the traditional Generalized Geometry Holdup (GGH) approach, using HMS3 software, with an area calibration and self-attenuation corrected with an empirical correction factor of 1.06. A result of 172 grams of 235 U was reported. The actual quantity of 235 U in the filter was approximately 1700g. Because of this unusually large discrepancy, the measurement of HEPA filters will be discussed. Various techniques for measuring HEPA filters will be described using the measurement of a 24 by 24 by 12 inch HEPA filter as an example. A new method to correct for self attenuation will be proposed for this measurement Following the discussion of the 24 by 24 by 12 inch HEPA filter, the measurement of the 8 by 8 by 6 inch will be discussed in detail

  6. High flow ceramic pot filters.

    Science.gov (United States)

    van Halem, D; van der Laan, H; Soppe, A I A; Heijman, S G J

    2017-11-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6-19 L h -1 ), but initial LRVs for E. coli of high flow filters was slightly lower than for regular ceramic pot filters. This disadvantage was, however, only temporarily as the clogging in high flow filters had a positive effect on the LRV for E. coli (from below 1 to 2-3 after clogging). Therefore, it can be carefully concluded that regular ceramic pot filters perform better initially, but after clogging, the high flow filters have a higher flow rate as well as a higher LRV for E. coli. To improve the initial performance of new high flow filters, it is recommended to further utilize residence time of the water in the receptacle, since additional E. coli inactivation was observed during overnight storage. Although a relationship was observed between flow rate and LRV of MS2 bacteriophages, both regular and high flow filters were unable to reach over 2 LRV. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. A New Quaternion-Based Kalman Filter for Real-Time Attitude Estimation Using the Two-Step Geometrically-Intuitive Correction Algorithm.

    Science.gov (United States)

    Feng, Kaiqiang; Li, Jie; Zhang, Xiaoming; Shen, Chong; Bi, Yu; Zheng, Tao; Liu, Jun

    2017-09-19

    In order to reduce the computational complexity, and improve the pitch/roll estimation accuracy of the low-cost attitude heading reference system (AHRS) under conditions of magnetic-distortion, a novel linear Kalman filter, suitable for nonlinear attitude estimation, is proposed in this paper. The new algorithm is the combination of two-step geometrically-intuitive correction (TGIC) and the Kalman filter. In the proposed algorithm, the sequential two-step geometrically-intuitive correction scheme is used to make the current estimation of pitch/roll immune to magnetic distortion. Meanwhile, the TGIC produces a computed quaternion input for the Kalman filter, which avoids the linearization error of measurement equations and reduces the computational complexity. Several experiments have been carried out to validate the performance of the filter design. The results demonstrate that the mean time consumption and the root mean square error (RMSE) of pitch/roll estimation under magnetic disturbances are reduced by 45.9% and 33.8%, respectively, when compared with a standard filter. In addition, the proposed filter is applicable for attitude estimation under various dynamic conditions.

  8. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Wells, George; Beaton, Dorcas E; Tugwell, Peter

    2014-01-01

    The "Discrimination" part of the OMERACT Filter asks whether a measure discriminates between situations that are of interest. "Feasibility" in the OMERACT Filter encompasses the practical considerations of using an instrument, including its ease of use, time to complete, monetary costs......, and interpretability of the question(s) included in the instrument. Both the Discrimination and Reliability parts of the filter have been helpful but were agreed on primarily by consensus of OMERACT participants rather than through explicit evidence-based guidelines. In Filter 2.0 we wanted to improve this definition...

  9. Filters in nuclear facilities

    International Nuclear Information System (INIS)

    Berg, K.H.; Wilhelm, J.G.

    1985-01-01

    The topics of the nine papers given include the behavior of HEPA filters during exposure to air flows of high humidity as well as of high differential pressure, the development of steel-fiber filters suitable for extreme operating conditions, and the occurrence of various radioactive iodine species in the exhaust air from boiling water reactors. In an introductory presentation the German view of the performance requirements to be met by filters in nuclear facilities as well as the present status of filter quality assurance are discussed. (orig.) [de

  10. Nanofiber Filters Eliminate Contaminants

    Science.gov (United States)

    2009-01-01

    With support from Phase I and II SBIR funding from Johnson Space Center, Argonide Corporation of Sanford, Florida tested and developed its proprietary nanofiber water filter media. Capable of removing more than 99.99 percent of dangerous particles like bacteria, viruses, and parasites, the media was incorporated into the company's commercial NanoCeram water filter, an inductee into the Space Foundation's Space Technology Hall of Fame. In addition to its drinking water filters, Argonide now produces large-scale nanofiber filters used as part of the reverse osmosis process for industrial water purification.

  11. Performance evaluation and modelling studies of gravel--coir fibre--sand multimedia stormwater filter.

    Science.gov (United States)

    Samuel, Manoj P; Senthilvel, S; Tamilmani, D; Mathew, A C

    2012-09-01

    A horizontal flow multimedia stormwater filter was developed and tested for hydraulic efficiency and pollutant removal efficiency. Gravel, coconut (Cocos nucifera) fibre and sand were selected as the media and filled in 1:1:1 proportion. A fabric screen made up of woven sisal hemp was used to separate the media. The adsorption behaviour of coir fibre was determined in a series of column and batch studies and the corresponding isotherms were developed. The hydraulic efficiency of the filter showed a diminishing trend as the sediment level in inflow increased. The filter exhibited 100% sediment removal at lower sediment concentrations in inflow water (>6 g L(-1)). The filter could remove NO3(-), SO4(2-) and total solids (TS) effectively. Removal percentages of Mg(2+) and Na(+) were also found to be good. Similar results were obtained from a field evaluation study. Studies were also conducted to determine the pattern of silt and sediment deposition inside the filter body. The effects of residence time and rate of flow on removal percentages of NO3(-) and TS were also investigated out. In addition, a multiple regression equation that mathematically represents the filtration process was developed. Based on estimated annual costs and returns, all financial viability criteria (internal rate of return, net present value and benefit-cost ratio) were found favourable and affordable to farmers for investment in the developed filtration system. The model MUSIC was calibrated and validated for field conditions with respect to the developed stormwater filter.

  12. Simon-nitinol filter

    International Nuclear Information System (INIS)

    Simon, M.; Kim, D.; Porter, D.H.; Kleshinski, S.

    1989-01-01

    This paper discusses a filter that exploits the thermal shape-memory properties of the nitinol alloy to achieve an optimized filter shape and a fine-bore introducer. Experimental methods and materials are given and results are analyzed

  13. GRIM-Filter: Fast seed location filtering in DNA read mapping using processing-in-memory technologies.

    Science.gov (United States)

    Kim, Jeremie S; Senol Cali, Damla; Xin, Hongyi; Lee, Donghyuk; Ghose, Saugata; Alser, Mohammed; Hassan, Hasan; Ergin, Oguz; Alkan, Can; Mutlu, Onur

    2018-05-09

    Seed location filtering is critical in DNA read mapping, a process where billions of DNA fragments (reads) sampled from a donor are mapped onto a reference genome to identify genomic variants of the donor. State-of-the-art read mappers 1) quickly generate possible mapping locations for seeds (i.e., smaller segments) within each read, 2) extract reference sequences at each of the mapping locations, and 3) check similarity between each read and its associated reference sequences with a computationally-expensive algorithm (i.e., sequence alignment) to determine the origin of the read. A seed location filter comes into play before alignment, discarding seed locations that alignment would deem a poor match. The ideal seed location filter would discard all poor match locations prior to alignment such that there is no wasted computation on unnecessary alignments. We propose a novel seed location filtering algorithm, GRIM-Filter, optimized to exploit 3D-stacked memory systems that integrate computation within a logic layer stacked under memory layers, to perform processing-in-memory (PIM). GRIM-Filter quickly filters seed locations by 1) introducing a new representation of coarse-grained segments of the reference genome, and 2) using massively-parallel in-memory operations to identify read presence within each coarse-grained segment. Our evaluations show that for a sequence alignment error tolerance of 0.05, GRIM-Filter 1) reduces the false negative rate of filtering by 5.59x-6.41x, and 2) provides an end-to-end read mapper speedup of 1.81x-3.65x, compared to a state-of-the-art read mapper employing the best previous seed location filtering algorithm. GRIM-Filter exploits 3D-stacked memory, which enables the efficient use of processing-in-memory, to overcome the memory bandwidth bottleneck in seed location filtering. We show that GRIM-Filter significantly improves the performance of a state-of-the-art read mapper. GRIM-Filter is a universal seed location filter that can be

  14. Filter cake breaker systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo H.F. [Poland Quimica Ltda., Duque de Caxias, RJ (Brazil)

    2004-07-01

    Drilling fluids filter cakes are based on a combination of properly graded dispersed particles and polysaccharide polymers. High efficiency filter cakes are formed by these combination , and their formation on wellbore walls during the drilling process has, among other roles, the task of protecting the formation from instantaneous or accumulative invasion of drilling fluid filtrate, granting stability to well and production zones. Filter cake minimizes contact between drilling fluid filtrate and water, hydrocarbons and clay existent in formations. The uniform removal of the filter cake from the entire interval is a critical factor of the completion process. The main methods used to breaking filter cake are classified into two groups, external or internal, according to their removal mechanism. The aim of this work is the presentation of these mechanisms as well their efficiency. (author)

  15. A Compact UWB Band-Pass Filter Using Embedded Circular Slot Structures for Improved Upper Stop-band Performance

    DEFF Research Database (Denmark)

    Shen, Ming; Ren, Jian; Mikkelsen, Jan Hvolgaard

    2016-01-01

    structures into the ring resonator. This is different from conventional designs using cascaded bandstop/low-pass filters for stop-band response suppression, which usually leads to big circuit sizes. And hence the proposed approach can reduce the circuit size significantly. A prototype filter with a compact...... size (13.6 mm×6.75 mm) has been implemented for experimental validation. The measured results show a −3 dB frequency band from 3.4 GHz to 11.7 GHz and > 20 dB upper stop-band suppression from 12.5 GHz to 20GHz....

  16. Trace element analysis of old exposed air filters: a feasibility study

    International Nuclear Information System (INIS)

    Pattenden, N.J.; Fisher, E.M.R.; Bones, E.M.

    1979-10-01

    A limited number of old exposed air filters from a network of sampling stations extending the length of North and South America have been analysed for many trace elements. (The network is run by the United States Department of Energy Environmental Measurements Laboratory). The objective was to assess the possible value of a large program of such measurements for providing information on the trace element concentrations in airborne particulates existing at the time of sample collection. On the basis of the evidence obtained, it is considered that valid information could be extracted in this way. In view of the extent of the store of old filters, which cover about a 10 year period up to the present day from stations spread over the North and South American continents and elsewhere, such a program appears to be well worthwhile. (author)

  17. Oblique Projection Polarization Filtering-Based Interference Suppressions for Radar Sensor Networks

    Directory of Open Access Journals (Sweden)

    Cao Bin

    2010-01-01

    Full Text Available The interferences coming from the radar members degrade the detection and recognition performance of the radar sensor networks (RSNs if the waveforms of the radar members are nonorthogonal. In this paper, we analyze the interferences by exploring the polarization information of the electromagnetic (EM waves. Then, we propose the oblique projection polarization filtering- (OPPF- based scheme to suppress the interferences while keeping the amplitude and phase of its own return in RSNs, even if the polarized states of the radar members are not orthogonal. We consider the cooperative RSNs environment where the polarization information of each radar member is known to all. The proposed method uses all radar members' polarization information to establish the corresponding filtering operator. The Doppler-shift and its uncertainty are independent of the polarization information, which contributes that the interferences can be suppressed without the utilization of the spatial, the temporal, the frequency, the time-delay and the Doppler-shift information. Theoretical analysis and the mathematical deduction show that the proposed scheme is a valid and simple implementation. Simulation results also demonstrate that this method can obtain a good filtering performance when dealing with the problem of interference suppressions for RSNs.

  18. Two-dimensional filtering of SPECT images using the Metz and Wiener filters

    International Nuclear Information System (INIS)

    King, M.A.; Schwinger, R.B.; Penney, B.C.; Doherty, P.W.

    1984-01-01

    Presently, single photon emission computed tomographic (SPECT) images are usually reconstructed by arbitrarily selecting a one-dimensional ''window'' function for use in reconstruction. A better method would be to automatically choose among a family of two-dimensional image restoration filters in such a way as to produce ''optimum'' image quality. Two-dimensional image processing techniques offer the advantages of a larger statistical sampling of the data for better noise reduction, and two-dimensional image deconvolution to correct for blurring during acquisition. An investigation of two such ''optimal'' digital image restoration techniques (the count-dependent Metz filter and the Wiener filter) was made. They were applied both as two-dimensional ''window'' functions for preprocessing SPECT images, and for filtering reconstructed images. Their performance was compared by measuring image contrast and per cent fractional standard deviation (% FSD) in multiple-acquisitions of the Jaszczak SPECT phantom at two different count levels. A statistically significant increase in image contrast and decrease in % FSD was observed with these techniques when compared to the results of reconstruction with a ramp filter. The adaptability of the techniques was manifested in a lesser % reduction in % FSD at the high count level coupled with a greater enhancement in image contrast. Using an array processor, processing time was 0.2 sec per image for the Metz filter and 3 sec for the Wiener filter. It is concluded that two-dimensional digital image restoration with these techniques can produce a significant increase in SPECT image quality

  19. Remotely operated top loading filter housing

    International Nuclear Information System (INIS)

    Ross, M.J.; Carter, J.A.

    1989-01-01

    A high-efficiency particulate air (HEPA) filter system was developed for the Fuel Processing Facility at the Idaho Chemical Processing Plant. The system utilizes commercially available HEPA filters and allows in-cell filters to be maintained using operator-controlled remote handling equipment. The remote handling tasks include transport of filters before and after replacement, removal and replacement of the filter from the housing, and filter containment

  20. Reconfigurable Mixed Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    Neelofer Afzal

    2014-01-01

    Full Text Available This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

  1. The statistical bandwidth of Butterworth filters

    Science.gov (United States)

    Davy, J. L.; Dunn, I. P.

    1987-06-01

    The precision of standard architectural acoustic measurements is a function of the statistical bandwidth of the band pass filters used in the measurements. The International and United States Standards on octave and fractional octave-band filters which specify the band pass filters used in architectural acoustics measurements give the effective bandwidth, but unfortunately not the statistical bandwidth of the filters. Both these Standards are currently being revised and both revisions require the use of Butterworth filter characteristics. In this paper it is shown theoretically that the ratio of statistical bandwidth to effective bandwidth for an nth order Butterworth band pass filter is {2n}/{(2n-1)}. This is verified experimentally for third-octave third-order Butterworth band pass filters. It is also shown experimentally that this formula is approximately correct for some non-Butterworth third-octave third-order band pass filters. Because of the importance of Butterworth filters in the revised Standards, the theory of Butterworth filters is reviewed and the formulae for Butterworth filters given in both revised Standards are derived.

  2. EMI filter design

    CERN Document Server

    Ozenbaugh, Richard Lee

    2011-01-01

    With today's electrical and electronics systems requiring increased levels of performance and reliability, the design of robust EMI filters plays a critical role in EMC compliance. Using a mix of practical methods and theoretical analysis, EMI Filter Design, Third Edition presents both a hands-on and academic approach to the design of EMI filters and the selection of components values. The design approaches covered include matrix methods using table data and the use of Fourier analysis, Laplace transforms, and transfer function realization of LC structures. This edition has been fully revised

  3. 21 CFR 211.72 - Filters.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Filters. 211.72 Section 211.72 Food and Drugs FOOD... shall not release fibers into such products. Fiber-releasing filters may be used when it is not possible to manufacture such products without the use of these filters. If use of a fiber-releasing filter is...

  4. UV Fluorescence Photography of Works of Art : Replacing the Traditional UV Cut Filters with Interference Filters

    Directory of Open Access Journals (Sweden)

    Luís BRAVO PEREIRA

    2010-09-01

    Full Text Available For many years filters like the Kodak Wratten E series, or the equivalent Schneider B+W 415, were used as standard UV cut filters, necessary to obtain good quality on UV Fluorescence photography. The only problem with the use of these filters is that, when they receive the UV radiation that they should remove, they present themselves an internal fluorescence as side effect, that usually reduce contrast and quality on the final image. This article presents the results of our experiences on using some innovative filters, that appeared available on the market in recent years, projected to adsorb UV radiation even more efficiently than with the mentioned above pigment based standard filters: the interference filters for UV rejection (and, usually, for IR rejection too manufactured using interference layers, that present better results than the pigment based filters. The only problem with interference filters type is that they are sensitive to the rays direction and, because of that, they are not adequate to wide-angle lenses. The internal fluorescence for three filters: the B+W 415 UV cut (equivalent to the Kodak Wratten 2E, pigment based, the B+W 486 UV IR cut (an interference type filter, used frequently on digital cameras to remove IR or UV and the Baader UVIR rejection filter (two versions of this interference filter were used had been tested and compared. The final quality of the UV fluorescence images seems to be of a superior quality when compared to the images obtained with classic filters.

  5. Filtering and deconvolution for bioluminescence imaging of small animals

    International Nuclear Information System (INIS)

    Akkoul, S.

    2010-01-01

    This thesis is devoted to analysis of bioluminescence images applied to the small animal. This kind of imaging modality is used in cancerology studies. Nevertheless, some problems are related to the diffusion and the absorption of the tissues of the light of internal bioluminescent sources. In addition, system noise and the cosmic rays noise are present. This influences the quality of the images and makes it difficult to analyze. The purpose of this thesis is to overcome these disturbing effects. We first have proposed an image formation model for the bioluminescence images. The processing chain is constituted by a filtering stage followed by a deconvolution stage. We have proposed a new median filter to suppress the random value impulsive noise which corrupts the acquired images; this filter represents the first block of the proposed chain. For the deconvolution stage, we have performed a comparative study of various deconvolution algorithms. It allowed us to choose a blind deconvolution algorithm initialized with the estimated point spread function of the acquisition system. At first, we have validated our global approach by comparing our obtained results with the ground truth. Through various clinical tests, we have shown that the processing chain allows a significant improvement of the spatial resolution and a better distinction of very close tumor sources, what represents considerable contribution for the users of bioluminescence images. (author)

  6. Novel Simplex Unscented Transform and Filter

    Institute of Scientific and Technical Information of China (English)

    Wan-Chun Li; Ping Wei; Xian-Ci Xiao

    2008-01-01

    In this paper, a new simplex unscented transform (UT) based Schmidt orthogonal algorithm and a new filter method based on this transform are proposed. This filter has less computation consumption than UKF (unscented Kalman filter), SUKF (simplex unscented Kalman filter) and EKF (extended Kalman filter). Computer simulation shows that this filter has the same performance as UKF and SUKF, and according to the analysis of the computational requirements of EKF, UKF and SUKF, this filter has preferable practicality value. Finally, the appendix shows the efficiency for this UT.

  7. Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter

    KAUST Repository

    Luo, Xiaodong; Hoteit, Ibrahim

    2011-01-01

    A robust ensemble filtering scheme based on the H∞ filtering theory is proposed. The optimal H∞ filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used

  8. OPTIMIZATION OF ADVANCED FILTER SYSTEMS; TOPICAL

    International Nuclear Information System (INIS)

    R.A. Newby; G.J. Bruck; M.A. Alvin; T.E. Lippert

    1998-01-01

    Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench-scale test program has also been developed based

  9. Cost/benefit evaluation of electrofibrous air filters

    International Nuclear Information System (INIS)

    Bergman, W.; Kuhl, W.; Biermann, A.; Lum, B.

    1986-01-01

    Experimental electric air filters based on the principle of superimposing an electric field over conventional fibrous air filters have been developed. The different experimental electric filters described in this report include prefilters for use in glove boxes and in ventilation systems, re-circulating air filters, electric HEPA filters, and high efficiency, high temperature air filters. In each case the large improvement in filter efficiency that occurs when a mechanical filter is electrified is demonstrated. Also a significant increase in the particle loading capacity of filters in many of our evaluations is demonstrated. Both laboratory and field test results are presented. This paper also demonstrates that the performance of all of our electric filter designs, except one, can be matched by conventional mechanical air filters and usually at a lower cost. The one exception is the high temperature, high efficiency electric air filter. In that case there is no mechanical filter media that can match the performance of the electric air filter. Our findings show that electric air filters are only cost effective compared to mechanical air filters when the performance of the mechanical air filter cannot be further improved by mechanical means. (author)

  10. Washing method of filter

    International Nuclear Information System (INIS)

    Izumidani, Masakiyo; Tanno, Kazuo.

    1978-01-01

    Purpose: To enable automatic filter operation and facilitate back-washing operation by back-washing filters used in a bwr nuclear power plant utilizing an exhaust gas from a ventilator or air conditioner. Method: Exhaust gas from an exhaust pipe of an ventilator or air conditioner is pressurized in a compressor and then introduced in a back-washing gas tank. Then, the exhaust gas pressurized to a predetermined pressure is blown from the inside to the outside of a filter to thereby separate impurities collected on the filter elements and introduce them to a waste tank. (Furukawa, Y.)

  11. Combination of Adaptive Feedback Cancellation and Binaural Adaptive Filtering in Hearing Aids

    Directory of Open Access Journals (Sweden)

    Anthony Lombard

    2009-01-01

    Full Text Available We study a system combining adaptive feedback cancellation and adaptive filtering connecting inputs from both ears for signal enhancement in hearing aids. For the first time, such a binaural system is analyzed in terms of system stability, convergence of the algorithms, and possible interaction effects. As major outcomes of this study, a new stability condition adapted to the considered binaural scenario is presented, some already existing and commonly used feedback cancellation performance measures for the unilateral case are adapted to the binaural case, and possible interaction effects between the algorithms are identified. For illustration purposes, a blind source separation algorithm has been chosen as an example for adaptive binaural spatial filtering. Experimental results for binaural hearing aids confirm the theoretical findings and the validity of the new measures.

  12. Auditory filters at low-frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Møller, Henrik

    2009-01-01

    -ear transfer function), the asymmetry of the auditory filter changed from steeper high-frequency slopes at 1000 Hz to steeper low-frequency slopes below 100 Hz. Increasing steepness at low-frequencies of the middle-ear high-pass filter is thought to cause this effect. The dynamic range of the auditory filter...... was found to steadily decrease with decreasing center frequency. Although the observed decrease in filter bandwidth with decreasing center frequency was only approximately monotonic, the preliminary data indicates the filter bandwidth does not stabilize around 100 Hz, e.g. it still decreases below...

  13. The history of ceramic filters.

    Science.gov (United States)

    Fujishima, S

    2000-01-01

    The history of ceramic filters is surveyed. Included is the history of piezoelectric ceramics. Ceramic filters were developed using technology similar to that of quartz crystal and electro-mechanical filters. However, the key to this development involved the theoretical analysis of vibration modes and material improvements of piezoelectric ceramics. The primary application of ceramic filters has been for consumer-market use. Accordingly, a major emphasis has involved mass production technology, leading to low-priced devices. A typical ceramic filter includes monolithic resonators and capacitors packaged in unique configurations.

  14. A Filtering Approach for Image-Guided Surgery With a Highly Articulated Surgical Snake Robot.

    Science.gov (United States)

    Tully, Stephen; Choset, Howie

    2016-02-01

    The objective of this paper is to introduce a probabilistic filtering approach to estimate the pose and internal shape of a highly flexible surgical snake robot during minimally invasive surgery. Our approach renders a depiction of the robot that is registered to preoperatively reconstructed organ models to produce a 3-D visualization that can be used for surgical feedback. Our filtering method estimates the robot shape using an extended Kalman filter that fuses magnetic tracker data with kinematic models that define the motion of the robot. Using Lie derivative analysis, we show that this estimation problem is observable, and thus, the shape and configuration of the robot can be successfully recovered with a sufficient number of magnetic tracker measurements. We validate this study with benchtop and in-vivo image-guidance experiments in which the surgical robot was driven along the epicardial surface of a porcine heart. This paper introduces a filtering approach for shape estimation that can be used for image guidance during minimally invasive surgery. The methods being introduced in this paper enable informative image guidance for highly articulated surgical robots, which benefits the advancement of robotic surgery.

  15. Optimizing spatial patterns with sparse filter bands for motor-imagery based brain-computer interface.

    Science.gov (United States)

    Zhang, Yu; Zhou, Guoxu; Jin, Jing; Wang, Xingyu; Cichocki, Andrzej

    2015-11-30

    Common spatial pattern (CSP) has been most popularly applied to motor-imagery (MI) feature extraction for classification in brain-computer interface (BCI) application. Successful application of CSP depends on the filter band selection to a large degree. However, the most proper band is typically subject-specific and can hardly be determined manually. This study proposes a sparse filter band common spatial pattern (SFBCSP) for optimizing the spatial patterns. SFBCSP estimates CSP features on multiple signals that are filtered from raw EEG data at a set of overlapping bands. The filter bands that result in significant CSP features are then selected in a supervised way by exploiting sparse regression. A support vector machine (SVM) is implemented on the selected features for MI classification. Two public EEG datasets (BCI Competition III dataset IVa and BCI Competition IV IIb) are used to validate the proposed SFBCSP method. Experimental results demonstrate that SFBCSP help improve the classification performance of MI. The optimized spatial patterns by SFBCSP give overall better MI classification accuracy in comparison with several competing methods. The proposed SFBCSP is a potential method for improving the performance of MI-based BCI. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Group Lifting Structures For Multirate Filter Banks, II: Linear Phase Filter Banks

    Energy Technology Data Exchange (ETDEWEB)

    Brislawn, Christopher M [Los Alamos National Laboratory

    2008-01-01

    The theory of group lifting structures is applied to linear phase lifting factorizations for the two nontrivial classes of two-channel linear phase perfect reconstruction filter banks, the whole-and half-sample symmetric classes. Group lifting structures defined for the reversible and irreversible classes of whole-and half-sample symmetric filter banks are shown to satisfy the hypotheses of the uniqueness theorem for group lifting structures. It follows that linear phase lifting factorizations of whole-and half-sample symmetric filter banks are therefore independent of the factorization methods used to compute them. These results cover the specification of user-defined whole-sample symmetric filter banks in Part 2 of the ISO JPEG 2000 standard.

  17. Plant monitoring and signal validation at HFIR

    International Nuclear Information System (INIS)

    Mullens, J.A.

    1991-01-01

    This paper describes a monitoring system for the Oak Ridge National Laboratory's (ORNL'S) High Flux Isotope Reactor (HFIR). HFIR is an 85 MW pressurized water reactor designed to produce isotopes and intense neutron beams. The monitoring system is described with respect to plant signals and computer system; monitoring overview; data acquisition, logging and network distribution; signal validation; status displays; reactor condition monitoring; reactor operator aids. Future work will include the addition of more plant signals, more signal validation and diagnostic capabilities, improved status display, integration of the system with the RELAP plant simulation and graphical interface, improved operator aids, and an alarm filtering system. 8 refs., 7 figs. (MB)

  18. A Novel Design of Sparse Prototype Filter for Nearly Perfect Reconstruction Cosine-Modulated Filter Banks

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2018-05-01

    Full Text Available Cosine-modulated filter banks play a major role in digital signal processing. Sparse FIR filter banks have lower implementation complexity than full filter banks, while keeping a good performance level. This paper presents a fast design paradigm for sparse nearly perfect-reconstruction (NPR cosine-modulated filter banks. First, an approximation function is introduced to reduce the non-convex quadratically constrained optimization problem to a linearly constrained optimization problem. Then, the desired sparse linear phase FIR prototype filter is derived through the orthogonal matching pursuit (OMP performed under the weighted l 2 norm. The simulation results demonstrate that the proposed scheme is an effective paradigm to design sparse NPR cosine-modulated filter banks.

  19. Kalman Filtering with Real-Time Applications

    CERN Document Server

    Chui, Charles K

    2009-01-01

    Kalman Filtering with Real-Time Applications presents a thorough discussion of the mathematical theory and computational schemes of Kalman filtering. The filtering algorithms are derived via different approaches, including a direct method consisting of a series of elementary steps, and an indirect method based on innovation projection. Other topics include Kalman filtering for systems with correlated noise or colored noise, limiting Kalman filtering for time-invariant systems, extended Kalman filtering for nonlinear systems, interval Kalman filtering for uncertain systems, and wavelet Kalman filtering for multiresolution analysis of random signals. Most filtering algorithms are illustrated by using simplified radar tracking examples. The style of the book is informal, and the mathematics is elementary but rigorous. The text is self-contained, suitable for self-study, and accessible to all readers with a minimum knowledge of linear algebra, probability theory, and system engineering.

  20. In-situ testing of HEPA filters in the nuclear Karlsruhe filter system

    International Nuclear Information System (INIS)

    Ohlmeyer, M.; Stotz, W.

    1977-01-01

    Nuclear plant operators and filter manufacturers are endeavouring to improve environmental protection by intensifying process control and/or improving filter quality. In-situ testing is an important element in these efforts since it represents a direct means of checking the success or otherwise of a particular development. The arrangements for in-situ testing should satisfy the following minimum requirements: the staff should not be exposed to risk during the test; the test method should be objective and reproducible as well as being as sensitive as possible; the test method should permit detection of individual leaks in the filter system so that they can be remedied as efficiently as possible; the test equipment should not necessitate modifications to the extract systems or plant construction; the test should be simple and capable of being carried out with a minimum of effort and equipment. GfK has developed the 'Nuclear-Karlsruhe' filter housing in accordance with these principles. This housing permits in-situ testing similar to the DIN 24184 visual oil-fog test or the DOP test. External visual checks on the general condition of the filter is also possible. A safe system of filter changing with a specially designed plastic bag attachment at an accessible height considerably increases the degree of protection of operating personnel

  1. Impact of Image Filters and Observations Parameters in CBCT for Identification of Mandibular Osteolytic Lesions.

    Science.gov (United States)

    Monteiro, Bruna Moraes; Nobrega Filho, Denys Silveira; Lopes, Patrícia de Medeiros Loureiro; de Sales, Marcelo Augusto Oliveira

    2012-01-01

    The aim of this study was to analyze the influence of filters (algorithms) to improve the image of Cone Beam Computed Tomography (CBCT) in diagnosis of osteolytic lesions of the mandible, in order to establish the protocols for viewing images more suitable for CBCT diagnostics. 15 dry mandibles in which perforations were performed, simulating lesions, were submitted to CBCT examination. Two examiners analyzed the images, using filters to improve image Hard, Normal, and Very Sharp, contained in the iCAT Vision software, and protocols for assessment: axial; sagittal and coronal; and axial, sagittal and coronal planes simultaneously (MPR), on two occasions. The sensitivity and specificity (validity) of the cone beam computed tomography (CBCT) have been demonstrated as the values achieved were above 75% for sensitivity and above 85% for specificity, reaching around 95.5% of sensitivity and 99% of specificity when we used the appropriate observation protocol. It was concluded that the use of filters (algorithms) to improve the CBCT image influences the diagnosis, due to the fact that all measured values were correspondingly higher when it was used the filter Very Sharp, which justifies its use for clinical activities, followed by Hard and Normal filters, in order of decreasing values.

  2. Impact of Image Filters and Observations Parameters in CBCT for Identification of Mandibular Osteolytic Lesions

    Directory of Open Access Journals (Sweden)

    Bruna Moraes Monteiro

    2012-01-01

    Full Text Available The aim of this study was to analyze the influence of filters (algorithms to improve the image of Cone Beam Computed Tomography (CBCT in diagnosis of osteolytic lesions of the mandible, in order to establish the protocols for viewing images more suitable for CBCT diagnostics. 15 dry mandibles in which perforations were performed, simulating lesions, were submitted to CBCT examination. Two examiners analyzed the images, using filters to improve image Hard, Normal, and Very Sharp, contained in the iCAT Vision software, and protocols for assessment: axial; sagittal and coronal; and axial, sagittal and coronal planes simultaneously (MPR, on two occasions. The sensitivity and specificity (validity of the cone beam computed tomography (CBCT have been demonstrated as the values achieved were above 75% for sensitivity and above 85% for specificity, reaching around 95.5% of sensitivity and 99% of specificity when we used the appropriate observation protocol. It was concluded that the use of filters (algorithms to improve the CBCT image influences the diagnosis, due to the fact that all measured values were correspondingly higher when it was used the filter Very Sharp, which justifies its use for clinical activities, followed by Hard and Normal filters, in order of decreasing values.

  3. Regenerative-filter-incinerator device

    Energy Technology Data Exchange (ETDEWEB)

    Rosebrock, T.L.

    1977-10-18

    A regenerative-filter-incinerator device, for use in the exhaust system of a diesel engine, includes a drum-like regenerative-heat exchanger-filter assembly rotatably mounted within a housing that is adapted to be installed directly in the exhaust gas stream discharged from a diesel engine as close to the engine as possible. The regenerative-heat exchanger-filter assembly provides an inner chamber which serves as a reaction chamber for the secondary combustion of exhaust gases including particulates discharged from the engine. The regenerative-heat exchanger-filter assembly includes separately rotatable heat exchange-filter elements pervious to radial flow of fluid therethrough and adapted to filter out particulates from the exhaust gases and to carry them into the reaction chamber. During engine operation, the reaction chamber is provided with a quantity of heat, as necessary, to effect secondary combustion of the exhaust gases and particulates by means of an auxiliary heat source and the heat generated within the reaction chamber is stored in the individual heat exchange-filter elements during the discharge of exhaust gases therethrough from the reaction chamber and this heat is then transferred to the inflowing volume of the exhaust gases so that, in effect, exhaust gas is discharged from the device at substantially the same temperature as it was during its inlet into the device from the engine.

  4. Determination of permeability of ultra-fine cupric oxide aerosol through military filters and protective filters

    Science.gov (United States)

    Kellnerová, E.; Večeřa, Z.; Kellner, J.; Zeman, T.; Navrátil, J.

    2018-03-01

    The paper evaluates the filtration and sorption efficiency of selected types of military combined filters and protective filters. The testing was carried out with the use of ultra-fine aerosol containing cupric oxide nanoparticles ranging in size from 7.6 nm to 299.6 nm. The measurements of nanoparticles were carried out using a scanning mobility particle sizer before and after the passage through the filter and a developed sampling device at the level of particle number concentration approximately 750000 particles·cm-3. The basic parameters of permeability of ultra-fine aerosol passing through the tested material were evaluated, in particular particle size, efficiency of nanoparticle capture by filter, permeability coefficient and overall filtration efficiency. Results indicate that the military filter and particle filters exhibited the highest aerosol permeability especially in the nanoparticle size range between 100–200 nm, while the MOF filters had the highest permeability in the range of 200 to 300 nm. The Filter Nuclear and the Health and Safety filter had 100% nanoparticle capture efficiency and were therefore the most effective. The obtained measurement results have shown that the filtration efficiency over the entire measured range of nanoparticles was sufficient; however, it was different for particular particle sizes.

  5. COMPUTING THERAPY FOR PRECISION MEDICINE: COLLABORATIVE FILTERING INTEGRATES AND PREDICTS MULTI-ENTITY INTERACTIONS.

    Science.gov (United States)

    Regenbogen, Sam; Wilkins, Angela D; Lichtarge, Olivier

    2016-01-01

    Biomedicine produces copious information it cannot fully exploit. Specifically, there is considerable need to integrate knowledge from disparate studies to discover connections across domains. Here, we used a Collaborative Filtering approach, inspired by online recommendation algorithms, in which non-negative matrix factorization (NMF) predicts interactions among chemicals, genes, and diseases only from pairwise information about their interactions. Our approach, applied to matrices derived from the Comparative Toxicogenomics Database, successfully recovered Chemical-Disease, Chemical-Gene, and Disease-Gene networks in 10-fold cross-validation experiments. Additionally, we could predict each of these interaction matrices from the other two. Integrating all three CTD interaction matrices with NMF led to good predictions of STRING, an independent, external network of protein-protein interactions. Finally, this approach could integrate the CTD and STRING interaction data to improve Chemical-Gene cross-validation performance significantly, and, in a time-stamped study, it predicted information added to CTD after a given date, using only data prior to that date. We conclude that collaborative filtering can integrate information across multiple types of biological entities, and that as a first step towards precision medicine it can compute drug repurposing hypotheses.

  6. Modelling of air flows in pleated filters and of their clogging by solid particles

    International Nuclear Information System (INIS)

    Del Fabbro, L.

    2002-01-01

    The devices of air cleaning against particles are widely spread in various branches of industry: nuclear, motor, food, electronic,...; among these devices, numerous are constituted by pleated porous media to increase the surface of filtration and thus to reduce the pressure drop, for given air flow. The objective of our work is to compensate a lack evident of knowledge on the evolution of the pressure drop of pleated filter during the clogging and to deduct a modelling from it, on the basis of experiments concerning industrial filters of nuclear and car types. The obtained model is a function of characteristics of the filtering medium and pleats, of the characteristics of solid particles deposited on the filter, of the mass of particles and of the aeraulic conditions of air flow. It also depends on data on the clogging of flat filters of equivalent medium. To elaborate this model of pressure drop, an initial stage was carried out in order to characterize, experimentally and numerically, the pressure drop and the distribution of air flow in clean pleated filters of nuclear (high efficiency particulate air filter, in fiberglasses) and car (mean efficiency filter, in fibers of cellulose) types. The numerical model allowed to understand the fundamental role played by the aeraulic resistance of the filtering medium. From an non-dimensional approach, we established a semi-empirical model of pressure drop for a clean pleated filter valid for both studied types of medium; this model is used of first base for the development of the final model of clogging. The study of the clogging of the filters showed the complexity of the phenomenon dependent mainly on a reduction of the surface of filtration. This observation brings us to propose a clogging of pleated filters in three phases. Both first phases are similar in those observed for flat filters, while last phase corresponds to a reduction of the surface of filtration and leads a strong increase of the filter pressure drop

  7. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  8. Modified unscented Kalman filter using modified filter gain and variance scale factor for highly maneuvering target tracking

    Institute of Scientific and Technical Information of China (English)

    Changyun Liu; Penglang Shui; Gang Wei; Song Li

    2014-01-01

    To improve the low tracking precision caused by lagged filter gain or imprecise state noise when the target highly maneu-vers, a modified unscented Kalman filter algorithm based on the improved filter gain and adaptive scale factor of state noise is pre-sented. In every filter process, the estimated scale factor is used to update the state noise covariance Qk, and the improved filter gain is obtained in the filter process of unscented Kalman filter (UKF) via predicted variance Pk|k-1, which is similar to the standard Kalman filter. Simulation results show that the proposed algorithm provides better accuracy and ability to adapt to the highly maneu-vering target compared with the standard UKF.

  9. Efficient Implementation of Complex Modulated Filter Banks Using Cosine and Sine Modulated Filter Banks

    Directory of Open Access Journals (Sweden)

    Viholainen Ari

    2006-01-01

    Full Text Available The recently introduced exponentially modulated filter bank (EMFB is a -channel uniform, orthogonal, critically sampled, and frequency-selective complex modulated filter bank that satisfies the perfect reconstruction (PR property if the prototype filter of an -channel PR cosine modulated filter bank (CMFB is used. The purpose of this paper is to present various implementation structures for the EMFBs in a unified framework. The key idea is to use cosine and sine modulated filter banks as building blocks and, therefore, polyphase, lattice, and extended lapped transform (ELT type of implementation solutions are studied. The ELT-based EMFBs are observed to be very competitive with the existing modified discrete Fourier transform filter banks (MDFT-FBs when comparing the number of multiplications/additions and the structural simplicity. In addition, EMFB provides an alternative channel stacking arrangement that could be more natural in certain subband processing applications and data transmission systems.

  10. A bag adapted for the handling of a filtering element or filter unit

    International Nuclear Information System (INIS)

    Marshall, D.A.G.

    1980-01-01

    The invention relates to a transparent, flexible, synthetic plastics bag adapted to contain a filter element or filter unit so that the latter can be inserted into or removed from a filter casing or duct while being contained in the bag. The bag has a neck portion which is capable of being removably secured in an air-tight manner on to a part of the casing, and gloves or glove portions are provided in, or are formed in, the wall of the bag to permit handles on the filter element or unit to be grasped. (author)

  11. An Easy-to-Use Airborne LiDAR Data Filtering Method Based on Cloth Simulation

    Directory of Open Access Journals (Sweden)

    Wuming Zhang

    2016-06-01

    Full Text Available Separating point clouds into ground and non-ground measurements is an essential step to generate digital terrain models (DTMs from airborne LiDAR (light detection and ranging data. However, most filtering algorithms need to carefully set up a number of complicated parameters to achieve high accuracy. In this paper, we present a new filtering method which only needs a few easy-to-set integer and Boolean parameters. Within the proposed approach, a LiDAR point cloud is inverted, and then a rigid cloth is used to cover the inverted surface. By analyzing the interactions between the cloth nodes and the corresponding LiDAR points, the locations of the cloth nodes can be determined to generate an approximation of the ground surface. Finally, the ground points can be extracted from the LiDAR point cloud by comparing the original LiDAR points and the generated surface. Benchmark datasets provided by ISPRS (International Society for Photogrammetry and Remote Sensing working Group III/3 are used to validate the proposed filtering method, and the experimental results yield an average total error of 4.58%, which is comparable with most of the state-of-the-art filtering algorithms. The proposed easy-to-use filtering method may help the users without much experience to use LiDAR data and related technology in their own applications more easily.

  12. Virtual microphone sensing through vibro-acoustic modelling and Kalman filtering

    Science.gov (United States)

    van de Walle, A.; Naets, F.; Desmet, W.

    2018-05-01

    This work proposes a virtual microphone methodology which enables full field acoustic measurements for vibro-acoustic systems. The methodology employs a Kalman filtering framework in order to combine a reduced high-fidelity vibro-acoustic model with a structural excitation measurement and small set of real microphone measurements on the system under investigation. By employing model order reduction techniques, a high order finite element model can be converted in a much smaller model which preserves the desired accuracy and maintains the main physical properties of the original model. Due to the low order of the reduced-order model, it can be effectively employed in a Kalman filter. The proposed methodology is validated experimentally on a strongly coupled vibro-acoustic system. The virtual sensor vastly improves the accuracy with respect to regular forward simulation. The virtual sensor also allows to recreate the full sound field of the system, which is very difficult/impossible to do through classical measurements.

  13. The magnetic centrifugal mass filter

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  14. The magnetic centrifugal mass filter

    Energy Technology Data Exchange (ETDEWEB)

    Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

    2011-09-15

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  15. Passband switchable microwave photonic multiband filter

    Science.gov (United States)

    Ge, Jia; Fok, Mable P.

    2015-01-01

    A reconfigurable microwave photonic (MWP) multiband filter with selectable and switchable passbands is proposed and experimentally demonstrated, with a maximum of 12 simultaneous passbands evenly distributed from 0 to 10 GHz. The scheme is based on the generation of tunable optical comb lines using a two-stage Lyot loop filter, such that various filter tap spacings and spectral combinations are obtained for the configuration of the MWP filter. Through polarization state adjustment inside the Lyot loop filter, an optical frequency comb with 12 different comb spacings is achieved, which corresponds to a MWP filter with 12 selectable passbands. Center frequencies of the filter passbands are switchable, while the number of simultaneous passbands is tunable from 1 to 12. Furthermore, the MWP multiband filter can either work as an all-block, single-band or multiband filter with various passband combinations, which provide exceptional operation flexibility. All the passbands have over 30 dB sidelobe suppression and 3-dB bandwidth of 200 MHz, providing good filter selectivity. PMID:26521693

  16. Randomized Filtering Algorithms

    DEFF Research Database (Denmark)

    Katriel, Irit; Van Hentenryck, Pascal

    2008-01-01

    of AllDifferent and is generalization, the Global Cardinality Constraint. The first delayed filtering scheme is a Monte Carlo algorithm: its running time is superior, in the worst case, to that of enforcing are consistency after every domain event, while its filtering effectiveness is analyzed...... in the expected sense. The second scheme is a Las Vegas algorithm using filtering triggers: Its effectiveness is the same as enforcing are consistency after every domain event, while in the expected case it is faster by a factor of m/n, where n and m are, respectively, the number of nodes and edges...

  17. Comparison of robust H∞ filter and Kalman filter for initial alignment of inertial navigation system

    Institute of Scientific and Technical Information of China (English)

    HAO Yan-ling; CHEN Ming-hui; LI Liang-jun; XU Bo

    2008-01-01

    There are many filtering methods that can be used for the initial alignment of an integrated inertial navigation system.This paper discussed the use of GPS,but focused on two kinds of filters for the initial alignment of an integrated strapdown inertial navigation system (SINS).One method is based on the Kalman filter (KF),and the other is based on the robust filter.Simulation results showed that the filter provides a quick transient response and a little more accurate estimate than KF,given substantial process noise or unknown noise statistics.So the robust filter is an effective and useful method for initial alignment of SINS.This research should make the use of SINS more popular,and is also a step for further research.

  18. Tunable electro-optic filter stack

    Science.gov (United States)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

    2017-09-05

    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  19. The intractable cigarette ‘filter problem’

    Science.gov (United States)

    2011-01-01

    Background When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the ‘filter problem’. These extensive filter research and development efforts suggest a phase of genuine optimism among cigarette designers that cigarette filters could be engineered to mitigate the health hazards of smoking. Objective This paper explores the early history of cigarette filter research and development in order to elucidate why and when seemingly sincere filter engineering efforts devolved into manipulations in cigarette design to sustain cigarette marketing and mitigate consumers' concerns about the health consequences of smoking. Methods Relevant word and phrase searches were conducted in the Legacy Tobacco Documents Library online database, Google Patents, and media and medical databases including ProQuest, JSTOR, Medline and PubMed. Results 13 tobacco industry documents were identified that track prominent developments involved in what the industry referred to as the ‘filter problem’. These reveal a period of intense focus on the ‘filter problem’ that persisted from the mid-1950s to the mid-1960s, featuring collaborations between cigarette producers and large American chemical and textile companies to develop effective filters. In addition, the documents reveal how cigarette filter researchers' growing scientific knowledge of smoke chemistry led to increasing recognition that filters were unlikely to offer significant health protection. One of the primary concerns of cigarette producers was to design cigarette filters that could be economically incorporated into the massive scale of cigarette

  20. Avoiding the Use of Exhausted Drinking Water Filters: A Filter-Clock Based on Rusting Iron

    Directory of Open Access Journals (Sweden)

    Arnaud Igor Ndé-Tchoupé

    2018-05-01

    Full Text Available Efficient but affordable water treatment technologies are currently sought to solve the prevalent shortage of safe drinking water. Adsorption-based technologies are in the front-line of these efforts. Upon proper design, universally applied materials (e.g., activated carbons, bone chars, metal oxides are able to quantitatively remove inorganic and organic pollutants as well as pathogens from water. Each water filter has a defined removal capacity and must be replaced when this capacity is exhausted. Operational experience has shown that it may be difficult to convince some low-skilled users to buy new filters after a predicted service life. This communication describes the quest to develop a filter-clock to encourage all users to change their filters after the designed service life. A brief discussion on such a filter-clock based on rusting of metallic iron (Fe0 is presented. Integrating such filter-clocks in the design of water filters is regarded as essential for safeguarding public health.

  1. Heterogeneous counting on filter support media

    International Nuclear Information System (INIS)

    Long, E.; Kohler, V.; Kelly, M.J.

    1976-01-01

    Many investigators in the biomedical research area have used filter paper as the support for radioactive samples. This means that a heterogeneous counting of sample sometimes results. The count rate of a sample on a filter will be affected by positioning, degree of dryness, sample application procedure, the type of filter, and the type of cocktail used. Positioning of the filter (up or down) in the counting vial can cause a variation of 35% or more when counting tritiated samples on filter paper. Samples of varying degrees of dryness when added to the counting cocktail can cause nonreproducible counts if handled improperly. Count rates starting at 2400 CPM initially can become 10,000 CPM in 24 hours for 3 H-DNA (deoxyribonucleic acid) samples dried on standard cellulose acetate membrane filters. Data on cellulose nitrate filters show a similar trend. Sample application procedures in which the sample is applied to the filter in a small spot or on a large amount of the surface area can cause nonreproducible or very low counting rates. A tritiated DNA sample, when applied topically, gives a count rate of 4,000 CPM. When the sample is spread over the whole filter, 13,400 CPM are obtained with a much better coefficient of variation (5% versus 20%). Adding protein carrier (bovine serum albumin-BSA) to the sample to trap more of the tritiated DNA on the filter during the filtration process causes a serious beta absorption problem. Count rates which are one-fourth the count rate applied to the filter are obtained on calibrated runs. Many of the problems encountered can be alleviated by a proper choice of filter and the use of a liquid scintillation cocktail which dissolves the filter. Filter-Solv has been used to dissolve cellulose nitrate filters and filters which are a combination of cellulose nitrate and cellulose acetate. Count rates obtained for these dissolved samples are very reproducible and highly efficient

  2. Evaluation of self-contained HEPA filter

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, T.E. [Westinghouse Hanford Company, Richland, WA (United States)

    1995-02-01

    This paper presents the results of an evaluation of a self-contained high-efficiency particulate air filter (SHEPA) used in nuclear applications. A SCHEPA consists of filter medium encapsulated in a casing that is part of the system boundary. The SCHEPA filter serves as a combination of filter housing and filter. The filter medium is attached directly to the casing using adhesive as a bonding agent. A cylindrical connection in the middle of the end caps connects the filter assembly to adjoining ductwork. The SCHEPA must perform the functions of a filter housing, filter frame, and filter. It was recognized that the codes and standards do not address the SCHEPA specifically. Therefore, the investigation evaluated the SCHEPA against current codes and standards related to the functional requirements of an air-cleaning system. The specific standards used are required by DOE Order 6430.1A{sup 1} and include ASME N509{sup 3}, ASME N510{sup 4}, ERDA 76-21{sup 5}, MIL-F-51068F{sup 6}, NFPA 90A, {sup 7} and NFPA 91{sup 8}. The evaluation does not address whether the SCHEPA as a standard (off-the-shelf) filter could be upgraded to meet the current code requirements for an air-cleaning unit. The evaluation also did not consider how the SCHEPA was used in a system (e.g., whether it was under positive or negative pressure or whether it served as an air inlet filter to prevent contamination releases under system pressurization). The results of the evaluation show that, the SCHEPA filter does not meet design, fabrication, testing, and documentation requirements of ASME N509{sup 3} and ASME N510{sup 4}. The paper will identify these deficiencies. Specific exhaust system requirements and application should be considered when an evaluation of the SCHEPA filter is being performed in existing systems. When new designs are being comtemplated, other types of HEPA filter housings can be used in lieu of the SCHEPA filter.

  3. Experience with three percutaneous vena cava filters

    International Nuclear Information System (INIS)

    McCowan, T.C.; Ferris, E.J.; Harshfield, D.L.; Hassell, D.R.; Baker, M.L.

    1987-01-01

    Twenty-one Kimray-Greenfield, 33 bird's nest, and 19 Amplatz vena cava filters were placed percutaneously. The Kimray-Greenfield filter was the most difficult to insert. The major problem was the insertion site, which required venipuncture with a 24-F catheter. Minor hemorrhage was frequent, and femoral vein thrombosis occurred in four patients. No migration, caval thrombosis, or pulmonary emboli were seen after Kimray-Greenfield filter placement. The bird's nest filter was relatively easy to insert, although in two cases the filter prongs could not be adequately seated in the wall of the inferior vena cava. Three patients with bird's nest filters had thrombosis below the filter, and three filters migrated to the heart. One migrated filter could not be removed. One patient had multiple small pulmonary emboli at autopsy. No other pulmonary emboli after filter placement were noted. The Amplatz filter was the easiest of the three filters to insert. Only one patient with an Amplatz filter had thrombosis of the vena cava below the filter. No filter migrations were documented, and no recurrent pulmonary emboli were found on clinical or radiologic follow-up. The Amplatz vena cava filter is easier to place than percutaneous Kimray-Greenfield or bird's nest filters, has a low complication rate, and has proven to be clinically effective in preventing pulmonary emboli

  4. Noise reduction with complex bilateral filter.

    Science.gov (United States)

    Matsumoto, Mitsuharu

    2017-12-01

    This study introduces a noise reduction technique that uses a complex bilateral filter. A bilateral filter is a nonlinear filter originally developed for images that can reduce noise while preserving edge information. It is an attractive filter and has been used in many applications in image processing. When it is applied to an acoustical signal, small-amplitude noise is reduced while the speech signal is preserved. However, a bilateral filter cannot handle noise with relatively large amplitudes owing to its innate characteristics. In this study, the noisy signal is transformed into the time-frequency domain and the filter is improved to handle complex spectra. The high-amplitude noise is reduced in the time-frequency domain via the proposed filter. The features and the potential of the proposed filter are also confirmed through experiments.

  5. Filter bed systems treating domestic wastewater in the Nordic countries - Performance and reuse of filter media

    DEFF Research Database (Denmark)

    Jenssen, Petter D.; Krogstad, T.; Paruch, A.M.

    2010-01-01

    Nine filter beds have been constructed in the Nordic countries, Denmark, Finland, Norway and Sweden. Filter beds consist of a septic tank followed by an aerobic pre-treatment biofilter and a subsequent saturated flow grass-covered filter. Thus, filter beds are similar to subsurface flow construct...

  6. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  7. Filtering Performance Comparison of Kernel and Wavelet Filters for Reactivity Signal Noise

    International Nuclear Information System (INIS)

    Park, Moon Ghu; Shin, Ho Cheol; Lee, Yong Kwan; You, Skin

    2006-01-01

    Nuclear reactor power deviation from the critical state is a parameter of specific interest defined by the reactivity measuring neutron population. Reactivity is an extremely important quantity used to define many of the reactor startup physics parameters. The time dependent reactivity is normally determined by solving the using inverse neutron kinetics equation. The reactivity computer is a device to provide an on-line solution of the inverse kinetics equation. The measurement signal of the neutron density is normally noise corrupted and the control rods movement typically gives reactivity variation with edge signals like saw teeth. Those edge regions should be precisely preserved since the measured signal is used to estimate the reactivity wroth which is a crucial parameter to assure the safety of the nuclear reactors. In this paper, three kind of edge preserving noise filters are proposed and their performance is demonstrated using stepwise signals. The tested filters are based on the unilateral, bilateral kernel and wavelet filters which are known to be effective in edge preservation. The bilateral filter shows a remarkable improvement compared with unilateral kernel and wavelet filters

  8. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers.

    Science.gov (United States)

    Buyel, Johannes F; Gruchow, Hannah M; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m(-2) when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre-coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m(-2) with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

  9. Depth filters containing diatomite achieve more efficient particle retention than filters solely containing cellulose fibers

    Directory of Open Access Journals (Sweden)

    Johannes Felix Buyel

    2015-12-01

    Full Text Available The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g. when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m-2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU when diatomite filters were used. We also tested pre coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m-2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

  10. Digital notch filter based active damping for LCL filters

    DEFF Research Database (Denmark)

    Yao, Wenli; Yang, Yongheng; Zhang, Xiaobin

    2015-01-01

    . In contrast, the active damping does not require any dissipation elements, and thus has become of increasing interest. As a result, a vast of active damping solutions have been reported, among which multi-loop control systems and additional sensors are necessary, leading to increased cost and complexity....... In this paper, a notch filter based active damping without the requirement of additional sensors is proposed, where the inverter current is employed as the feedback variable. Firstly, a design method of the notch filter for active damping is presented. The entire system stability has then been investigated...... in the z-domain. Simulations and experiments are carried out to verify the proposed active damping method. Both results have confirmed that the notch filter based active damping can ensure the entire system stability in the case of resonances with a good system performance....

  11. Implicit LES using adaptive filtering

    Science.gov (United States)

    Sun, Guangrui; Domaradzki, Julian A.

    2018-04-01

    In implicit large eddy simulations (ILES) numerical dissipation prevents buildup of small scale energy in a manner similar to the explicit subgrid scale (SGS) models. If spectral methods are used the numerical dissipation is negligible but it can be introduced by applying a low-pass filter in the physical space, resulting in an effective ILES. In the present work we provide a comprehensive analysis of the numerical dissipation produced by different filtering operations in a turbulent channel flow simulated using a non-dissipative, pseudo-spectral Navier-Stokes solver. The amount of numerical dissipation imparted by filtering can be easily adjusted by changing how often a filter is applied. We show that when the additional numerical dissipation is close to the subgrid-scale (SGS) dissipation of an explicit LES the overall accuracy of ILES is also comparable, indicating that periodic filtering can replace explicit SGS models. A new method is proposed, which does not require any prior knowledge of a flow, to determine the filtering period adaptively. Once an optimal filtering period is found, the accuracy of ILES is significantly improved at low implementation complexity and computational cost. The method is general, performing well for different Reynolds numbers, grid resolutions, and filter shapes.

  12. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  13. PSpice for filters and transmission lines

    CERN Document Server

    Tobin, Paul

    2007-01-01

    In this book, PSpice for Filters and Transmission Lines, we examine a range of active and passive filters where each design is simulated using the latest Cadence Orcad V10.5 PSpice capture software. These filters cannot match the very high order digital signal processing (DSP) filters considered in PSpice for Digital Signal Processing, but nevertheless these filters have many uses. The active filters considered were designed using Butterworth and Chebychev approximation loss functions rather than using the 'cookbook approach' so that the final design will meet a given specification in an exact

  14. Bottom loaded filter for radioactive liquids

    International Nuclear Information System (INIS)

    Wendland, W.G.

    1983-01-01

    This invention relates to equipment for filtering liquids and more particularly to filter assemblies for use with radioactive by-products of nuclear power plants. The invention provides a compact, bottom-loaded filter assembly that can be quickly and safely loaded and unloaded without the use of complex remote equipment. The assembly is integrally shielded and does not require external shielding. The closure hatch may be automatically aligned to facilitate quick sealing attachment after replacement of the filter cartridge, and the filter cartridge may be automatically positioned within the filter housing during the replacement operation

  15. In Situ Cleanable Alternative HEPA Filter Media

    International Nuclear Information System (INIS)

    Adamson, D. J.; Terry, M. T.

    2002-01-01

    The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the Department of

  16. Modelling modulation perception : modulation low-pass filter or modulation filter bank?

    NARCIS (Netherlands)

    Dau, T.; Kollmeier, B.; Kohlrausch, A.G.

    1995-01-01

    In current models of modulation perception, the stimuli are first filtered and nonlinearly transformed (mostly half-wave rectified). In order to model the low-pass characteristic of measured modulation transfer functions, the next stage in the models is a first-order low-pass filter with a typical

  17. Context discovery using attenuated Bloom codes: model description and validation

    NARCIS (Netherlands)

    Liu, F.; Heijenk, Geert

    A novel approach to performing context discovery in ad-hoc networks based on the use of attenuated Bloom filters is proposed in this report. In order to investigate the performance of this approach, a model has been developed. This document describes the model and its validation. The model has been

  18. Experimental and numerical study of pleated filters clogging

    International Nuclear Information System (INIS)

    Gervais, Pierre-Colin

    2013-01-01

    Pleated filters are widely used in air treatments because of the advantageous effective surface to overall dimension ratio they offer. Their major drawback though resides in their reduced lifetime which still needs to be controlled. Indeed, when clogging, the pressure drop considerably increases, the filtration flow is then no longer maintained which might lead to the deterioration of the media. It is then crucial to characterize the evolution of the pressure drop under operating conditions in order to best design these equipments. Part of our work consisted in studying how the operating conditions influence the geometry of the deposit. To do so, we used Single- Photon Emission Computed Tomography (SPECT), a non-destructive imaging technique that keeps intact the particle structuring. The visualization of aerosol deposit at the beginning of the filtration process allows observing preferential particle deposition on the whole height of the pleat. A numerical approach was used to study the permeability of bimodal fibrous media and we experimentally studied the local velocity as well as the biphasic flow inside pleated filter media. Comparison between experiments and simulations allowed us to validate the Geodict code for a wide range of media properties and velocities. Regarding bimodal fibrous media, the fast data acquisition has allowed testing several existing models which resulted in classifying them in a unique way. If the experimental results on the initial deposition in pleated filters are encouraging, those related to beforehand clogging point to several improvements regarding the technique we used. (author) [fr

  19. Frequency Domain Image Filtering Using CUDA

    Directory of Open Access Journals (Sweden)

    Muhammad Awais Rajput

    2014-10-01

    Full Text Available In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA?s CUDA (Compute Unified Device Architecture. In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA?s parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butterworth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output image quality on both the processing architectures

  20. Frequency domain image filtering using cuda

    International Nuclear Information System (INIS)

    Rajput, M.A.; Khan, U.A.

    2014-01-01

    In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA's CUDA (Compute Unified Device Architecture). In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform) which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA's parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butter worth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output) image quality on both the processing architectures. (author)

  1. Kalman filtering with real-time applications

    CERN Document Server

    Chui, Charles K

    2017-01-01

    This new edition presents a thorough discussion of the mathematical theory and computational schemes of Kalman filtering. The filtering algorithms are derived via different approaches, including a direct method consisting of a series of elementary steps, and an indirect method based on innovation projection. Other topics include Kalman filtering for systems with correlated noise or colored noise, limiting Kalman filtering for time-invariant systems, extended Kalman filtering for nonlinear systems, interval Kalman filtering for uncertain systems, and wavelet Kalman filtering for multiresolution analysis of random signals. Most filtering algorithms are illustrated by using simplified radar tracking examples. The style of the book is informal, and the mathematics is elementary but rigorous. The text is self-contained, suitable for self-study, and accessible to all readers with a minimum knowledge of linear algebra, probability theory, and system engineering. Over 100 exercises and problems with solutions help de...

  2. Modified signed-digit trinary addition using synthetic wavelet filter

    Science.gov (United States)

    Iftekharuddin, K. M.; Razzaque, M. A.

    2000-09-01

    The modified signed-digit (MSD) number system has been a topic of interest as it allows for parallel carry-free addition of two numbers for digital optical computing. In this paper, harmonic wavelet joint transform (HWJT)-based correlation technique is introduced for optical implementation of MSD trinary adder implementation. The realization of the carry-propagation-free addition of MSD trinary numerals is demonstrated using synthetic HWJT correlator model. It is also shown that the proposed synthetic wavelet filter-based correlator shows high performance in logic processing. Simulation results are presented to validate the performance of the proposed technique.

  3. Box-particle intensity filter

    OpenAIRE

    Schikora, Marek; Gning, Amadou; Mihaylova, Lyudmila; Cremers, Daniel; Koch, Wofgang; Streit, Roy

    2012-01-01

    This paper develops a novel approach for multi-target tracking, called box-particle intensity filter (box-iFilter). The approach is able to cope with unknown clutter, false alarms and estimates the unknown number of targets. Furthermore, it is capable of dealing with three sources of uncertainty: stochastic, set-theoretic and data association uncertainty. The box-iFilter reduces the number of particles significantly, which improves the runtime considerably. The low particle number enables thi...

  4. Filters for radioactive liquid wastes

    International Nuclear Information System (INIS)

    Koshiba, Yukihiko; Kawashima, Akio

    1980-01-01

    In the crud generated in the reactor cooling water for nuclear power plants, iron oxides (hematite and magnetite) are contained as the main components, and also Co, Mn, Fe, Cr exist as radioactive nuclides. A new filter to separate these cruds, nuclepore membrane filter (NPMF), was investigated for its adaptability, and has been adopted as a practical filter for radioactive liquid wastes. The NPMF has such features as the possibility of complete automation of operation, no generation of secondary wastes, and easy maintenance, because the NPMF has uniform circular holes in poly-carbonate thin films, and shows the properties of stable filtering of particulates, capability of back washing, and others. The elements mounted in a practical system have such construction that the membrane is cut in the form of doughnut, and sandwiched with 100 mesh polyester nets (spacer); the obtained unit filter (cassette) is mounted on the stackable plate of the same size; and 80 pieces of this cassette are formed in a filter of 4 m 2 filtering area. The performance varies with the properties of suspended matters and the turbidity of wastes. For example, the filtered liquid of 0.1 ppm or less can be obtained when the 1 μm filter material is used to treat the liquid waste containing 1 to 100 ppm suspended matters. Usually back washed water is produced by about 1/100 of treated liquid wastes. The lifetime of the membrane is expected to be 1 or 2 years if crud is the main component. (Wakatsuki, Y.)

  5. Penetration of Combustion Aerosol Particles Through Filters of NIOSH-Certified Filtering Facepiece Respirators (FFRs).

    Science.gov (United States)

    Gao, Shuang; Kim, Jinyong; Yermakov, Michael; Elmashae, Yousef; He, Xinjian; Reponen, Tiina; Grinshpun, Sergey A

    2015-01-01

    Filtering facepiece respirators (FFRs) are commonly worn by first responders, first receivers, and other exposed groups to protect against exposure to airborne particles, including those originated by combustion. Most of these FFRs are NIOSH-certified (e.g., N95-type) based on the performance testing of their filters against charge-equilibrated aerosol challenges, e.g., NaCl. However, it has not been examined if the filtration data obtained with the NaCl-challenged FFR filters adequately represent the protection against real aerosol hazards such as combustion particles. A filter sample of N95 FFR mounted on a specially designed holder was challenged with NaCl particles and three combustion aerosols generated in a test chamber by burning wood, paper, and plastic. The concentrations upstream (Cup) and downstream (Cdown) of the filter were measured with a TSI P-Trak condensation particle counter and a Grimm Nanocheck particle spectrometer. Penetration was determined as (Cdown/Cup) ×100%. Four test conditions were chosen to represent inhalation flows of 15, 30, 55, and 85 L/min. Results showed that the penetration values of combustion particles were significantly higher than those of the "model" NaCl particles (p combustion particles. Aerosol type, inhalation flow rate and particle size were significant (p combustion particles through R95 and P95 FFR filters (were tested in addition to N95) were not significantly higher than that obtained with NaCl particles. The findings were attributed to several effects, including the degradation of an N95 filter due to hydrophobic organic components generated into the air by combustion. Their interaction with fibers is anticipated to be similar to those involving "oily" particles. The findings of this study suggest that the efficiency of N95 respirator filters obtained with the NaCl aerosol challenge may not accurately predict (and rather overestimate) the filter efficiency against combustion particles.

  6. Smart wave filtering method of a rectangular panel using Hilbert transformers and its application to an adaptive control system

    International Nuclear Information System (INIS)

    Iwamoto, Hiroyuki; Tanaka, Nobuo; Hill, Simon G

    2010-01-01

    This paper concerns the active vibration control of a rectangular panel using smart sensors from the viewpoint of an active wave control theory. The objective of this paper is to present a new type of filter which enables the measurement of the wave amplitude of a rectangular panel in real time for the application of an adaptive feedforward control system which inactivates vibration modes. Firstly, a novel wave filtering method using smart PVDF sensors is proposed. It is found that the shaping function of smart sensors is a complex function. To realize the smart sensor in a practical situation, a Hilbert transformer is utilized to implement a phase shifter of 90° for broadband frequencies. Then, from the viewpoint of a numerical analysis, the characteristics of the proposed wave filter and the performance of the adaptive feedforward control system using the wave filter are discussed. Finally, experiments implementing the active wave control theory which uses the proposed wave filter are conducted, demonstrating the validity of the proposed method in suppressing the vibration of a rectangular panel

  7. Low-sensitivity active filter realization using a complex all-pass filter

    Science.gov (United States)

    Regalia, Phillip A.; Mitra, Sanjit K.

    1987-04-01

    A wide class of continuous-time transfer functions may be implemented as the parallel combination of two all-pass filters, including Butterworth, Chebyshev, and elliptic low-pass approximations of odd order. Here, the realization of even-order low-pass classical approximations is considered, and it is shown that they may be decomposed in terms of complex all-pass functions. A systematic realization approach, based on scattering domain simulation (i.e., wave active filters), allows for a low-sensitivity active filter implementation. Further insight into the low-sensitivity property is gained by connecting the insertion loss of doubly terminated antimetric networks with the imaginary return loss of complex lossless networks.

  8. The intractable cigarette ‘filter problem’

    OpenAIRE

    Harris, Bradford

    2011-01-01

    Background When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the ‘filter problem’. These extensive filter resea...

  9. MR image reconstruction via guided filter.

    Science.gov (United States)

    Huang, Heyan; Yang, Hang; Wang, Kang

    2018-04-01

    Magnetic resonance imaging (MRI) reconstruction from the smallest possible set of Fourier samples has been a difficult problem in medical imaging field. In our paper, we present a new approach based on a guided filter for efficient MRI recovery algorithm. The guided filter is an edge-preserving smoothing operator and has better behaviors near edges than the bilateral filter. Our reconstruction method is consist of two steps. First, we propose two cost functions which could be computed efficiently and thus obtain two different images. Second, the guided filter is used with these two obtained images for efficient edge-preserving filtering, and one image is used as the guidance image, the other one is used as a filtered image in the guided filter. In our reconstruction algorithm, we can obtain more details by introducing guided filter. We compare our reconstruction algorithm with some competitive MRI reconstruction techniques in terms of PSNR and visual quality. Simulation results are given to show the performance of our new method.

  10. Filter device for high density aerozol

    International Nuclear Information System (INIS)

    Karasawa, Hidetoshi; Endo, Masao; Utamura, Motoaki; Tozuka, Fumio; Tate, Hitoshi.

    1991-01-01

    In a reactor, filters for capturing aerozol particles at high concentration have such a structure that a great number of fine pores are formed. Aerozols are introduced to a filter portion from the place remote from a first inlet. Cloggings are caused successively from the places remote from the inlet. Even if the clogging should occur, since there are many pores, the performance of filters is not deteriorated. Further, the filter has a multi-layered structure. With such a constitution, if the filter at a first stage is clogged to increase the pressure, a partitioning plate is opened and fluids are introduced into a second filter. This is conducted successively to suppress the deterioration of the performance of the filter. In view of the above, even if cloggings should occur, the filter performance is not deteriorated and, accordingly, reactor container ventilation can be conducted at high reliability upon occurrence of accidents. (T.M.)

  11. A model-based adaptive state of charge estimator for a lithium-ion battery using an improved adaptive particle filter

    International Nuclear Information System (INIS)

    Ye, Min; Guo, Hui; Cao, Binggang

    2017-01-01

    Highlights: • Propose an improved adaptive particle swarm filter method. • The SoC estimation method for the battery based on the adaptive particle swarm filter is presented. • The algorithm is validated by the case study of different aged extent batteries. • The effectiveness and applicability of the algorithm are validated by the LiPB batteries. - Abstract: Obtaining accurate parameters, state of charge (SoC) and capacity of a lithium-ion battery is crucial for a battery management system, and establishing a battery model online is complex. In addition, the errors and perturbations of the battery model dramatically increase throughout the battery lifetime, making it more challenging to model the battery online. To overcome these difficulties, this paper provides three contributions: (1) To improve the robustness of the adaptive particle filter algorithm, an error analysis method is added to the traditional adaptive particle swarm algorithm. (2) An online adaptive SoC estimator based on the improved adaptive particle filter is presented; this estimator can eliminate the estimation error due to battery degradation and initial SoC errors. (3) The effectiveness of the proposed method is verified using various initial states of lithium nickel manganese cobalt oxide (NMC) cells and lithium-ion polymer (LiPB) batteries. The experimental analysis shows that the maximum errors are less than 1% for both the voltage and SoC estimations and that the convergence time of the SoC estimation decreased to 120 s.

  12. Convergence Results for the Gaussian Mixture Implementation of the Extended-Target PHD Filter and Its Extended Kalman Filtering Approximation

    Directory of Open Access Journals (Sweden)

    Feng Lian

    2012-01-01

    Full Text Available The convergence of the Gaussian mixture extended-target probability hypothesis density (GM-EPHD filter and its extended Kalman (EK filtering approximation in mildly nonlinear condition, namely, the EK-GM-EPHD filter, is studied here. This paper proves that both the GM-EPHD filter and the EK-GM-EPHD filter converge uniformly to the true EPHD filter. The significance of this paper is in theory to present the convergence results of the GM-EPHD and EK-GM-EPHD filters and the conditions under which the two filters satisfy uniform convergence.

  13. Multi-filter spectrophotometry simulations

    Science.gov (United States)

    Callaghan, Kim A. S.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys.

  14. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

    1994-12-31

    Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

  15. High temperature superconducting YBCO microwave filters

    Science.gov (United States)

    Aghabagheri, S.; Rasti, M.; Mohammadizadeh, M. R.; Kameli, P.; Salamati, H.; Mohammadpour-Aghdam, K.; Faraji-Dana, R.

    2018-06-01

    Epitaxial thin films of YBCO high temperature superconductor are widely used in telecommunication technology such as microwave filter, antenna, coupler and etc., due to their lower surface resistance and lower microwave loss than their normal conductor counterparts. Thin films of YBCO were fabricated by PLD technique on LAO substrate. Transition temperature and width were 88 K and 3 K, respectively. A filter pattern was designed and implemented by wet photolithography method on the films. Characterization of the filter at 77 K has been compared with the simulation results and the results for a made gold filter. Both YBCO and gold filters show high microwave loss. For YBCO filter, the reason may be due to the improper contacts on the feedlines and for gold filter, low thickness of the gold film has caused the loss increased.

  16. Practice patterns of retrievable inferior vena cava filters and predictors of filter retrieval in patients with pulmonary embolism.

    Science.gov (United States)

    Kang, Jieun; Ko, Heung-Kyu; Shin, Ji Hoon; Ko, Gi-Young; Jo, Kyung-Wook; Huh, Jin Won; Oh, Yeon-Mok; Lee, Sang-Do; Lee, Jae Seung

    2017-12-01

    Retrievable inferior vena cava (IVC) filters are increasingly used in patients with venous thromboembolism (VTE) who have contraindications to anticoagulant therapy. However, previous studies have shown that many retrievable filters are left permanently in patients. This study aimed to identify the common indications for IVC filter insertion, the filter retrieval rate, and the predictive factors for filter retrieval attempts. To this end, a retrospective cohort study was performed at a tertiary care center in South Korea between January 2010 and May 2016. Electronic medical charts were reviewed for patients with pulmonary embolism (PE) who underwent IVC filter insertion. A total of 439 cases were reviewed. The most common indication for filter insertion was a preoperative/procedural aim, followed by extensive iliofemoral deep vein thrombosis (DVT). Retrieval of the IVC filter was attempted in 44.9% of patients. The retrieval success rate was 93.9%. History of cerebral hemorrhage, malignancy, and admission to a nonsurgical department were the significant predictive factors of a lower retrieval attempt rate in multivariate analysis. With the increased use of IVC filters, more issues should be addressed before placing a filter and physicians should attempt to improve the filter retrieval rate.

  17. Successful Reach and Adoption of a workplace health promotion RCT targeting a group of high-risk workers

    DEFF Research Database (Denmark)

    Jørgensen, Marie B; Rasmussen, Charlotte D N; Ekner, Dorte

    2010-01-01

    BACKGROUND: Cleaners are rarely introduced to workplace health promotion programs. The study's objective was to evaluate the reach and adoption of a workplace randomized controlled trial (RCT) among cleaners in Denmark. METHODS: Cleaning businesses with at least 30 employees, that could offer...... a weekly 1-hour intervention during working hours, were invited to participate. Employees working at least 20 hours/week were invited to answer a screening questionnaire and consent to participate. Analyses determined the differences in health variables between responders and non-responders, consenters...... employees, 78% responded to the screening questionnaire and 49% consented to participate. Consenters and participants differed from non-consenters and non-participants by having higher BMI, more chronic diseases and poorer musculoskeletal health. CONCLUSIONS: This study indicates that workplace health...

  18. Measurement of filtration efficiency of Nuclepore filters challenged with polystyrene latex nanoparticles: experiments and modeling

    International Nuclear Information System (INIS)

    Ling, Tsz Yan; Wang Jing; Pui, David Y. H.

    2011-01-01

    Membrane filtration has been demonstrated to be effective for the removal of liquid-borne nanoparticles (NPs). Such technique can be applied to purify and disinfect drinking water as well as remove NPs in highly pure chemicals used in the industries. This study aims to study the filtration process of a model membrane filter, the Nuclepore filter. Experiments were carried out using standard filtration tools and the nanoparticle tracking analysis (NTA) technique was used to measure particle (50–500 nm) concentration upstream and downstream of the filter to determine the filtration efficiency. The NTA technique has been calibrated using 150-nm polystyrene latex particles to determine its accuracy of particle concentration measurement. Measurements were found reliable within a certain concentration limit (about 10 8 –10 10 particles/cm 3 ), which is dependent on the camera settings during the measurement. Experimental results are comparable with previously published data obtained using the aerosolization method, validating the capability of the NTA technique. The capillary tube model modified from that developed for aerosol filtration was found to be useful to represent the experimental results, when a sticking coefficient of 0.15 is incorporated. This suggests that only 15% of the particle collisions with the filter results in successful attachment. The small sticking coefficient found can be explained by the unfavorable surface interactions between the particles and the filter medium.

  19. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

    1997-07-01

    Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

  20. Optimal Nonlinear Filter for INS Alignment

    Institute of Scientific and Technical Information of China (English)

    赵瑞; 顾启泰

    2002-01-01

    All the methods to handle the inertial navigation system (INS) alignment were sub-optimal in the past. In this paper, particle filtering (PF) as an optimal method is used for solving the problem of INS alignment. A sub-optimal two-step filtering algorithm is presented to improve the real-time performance of PF. The approach combines particle filtering with Kalman filtering (KF). Simulation results illustrate the superior performance of these approaches when compared with extended Kalman filtering (EKF).

  1. Multiplier-free filters for wideband SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Christensen, Erik Lintz

    2001-01-01

    This paper derives a set of parameters to be optimized when designing filters for digital demodulation and range prefiltering in SAR systems. Aiming at an implementation in field programmable gate arrays (FPGAs), an approach for the design of multiplier-free filters is outlined. Design results...... are presented in terms of filter complexity and performance. One filter has been coded in VHDL and preliminary results indicate that the filter can meet a 2 GHz input sample rate....

  2. Design and construction of electronic filters

    International Nuclear Information System (INIS)

    Becerril Z, E.R.; Moreno P, C.; Salinas B, E.

    1979-01-01

    The design and construction of very low frequencies electronic filters which will be used for carrying out analysis of pile noise at Mexico's Nuclear Center Triga Mark III Reactor, in order to realize measurements of its parameters is presented. NIM norms and active filters with lineal integrated circuits were used: a. Band pass filter from 10 to 500 hertz, band width 50. b. Low pass filter from 0.001 to 10 hertz in 3 steps. c. Kalman Bucy filter, an analogical simulation of this filter was undertaken, obtained from a mathematical model of a Zero power experimental reactor, with the purpose to establish a control searching. (author)

  3. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude......; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet...

  4. Projects on filter testing in Sweden

    International Nuclear Information System (INIS)

    Normann, B.; Wiktorsson, C.

    1985-01-01

    The Swedish nuclear power program comprises twelve light water reactors. Nine are boiling water reactors of ASEA-ATOM design and three are pressurized water reactors of Westinghouse design. Of these, ten are in operation and two are under construction and planned to go into operation during late 1984 and early 1985, respectively. Frequent tests on the penetration of particles through HEPA filters, regular tests on the adsorption of methyl iodide in the stand-by carbon filter units by laboratory testing are discussed. The proposed new regulations are based on many years of experience of filter system operation and of tests in-situ and in the laboratory. Moisture and water are factors that affect the functioning of filters. In addition, high loading of dust can give rise to increased penetration through HEPA filters, however pinholes could have less influence on the total penetration. Laboratory tests show that DOP particles retain 30-40% in 90 mm carbon filters (8-12 mesh). However no effect on the ability of carbon to adsorb methyl iodide after DOP contamination in combined carbon/HEPA filters has been observed. Leakage from ventilation ducts can cause radioactive contamination problems during filter testing with radioiodine. In-situ testing of control-room filters has been performed using inactive methyl iodide. A type of carbon bed not previously used in Sweden has been introduced. Testing of this filter type is discussed

  5. Impact of an inferior vena cava filter retrieval algorithm on filter retrieval rates in a cancer population.

    Science.gov (United States)

    Litwin, Robert J; Huang, Steven Y; Sabir, Sharjeel H; Hoang, Quoc B; Ahrar, Kamran; Ahrar, Judy; Tam, Alda L; Mahvash, Armeen; Ensor, Joe E; Kroll, Michael; Gupta, Sanjay

    2017-09-01

    Our primary purpose was to assess the impact of an inferior vena cava filter retrieval algorithm in a cancer population. Because cancer patients are at persistently elevated risk for development of venous thromboembolism (VTE), our secondary purpose was to assess the incidence of recurrent VTE in patients who underwent filter retrieval. Patients with malignant disease who had retrievable filters placed at a tertiary care cancer hospital from August 2010 to July 2014 were retrospectively studied. A filter retrieval algorithm was established in August 2012. Patients and referring physicians were contacted in the postintervention period when review of the medical record indicated that filter retrieval was clinically appropriate. Patients were classified into preintervention (August 2010-July 2012) and postintervention (August 2012-July 2014) study cohorts. Retrieval rates and clinical pathologic records were reviewed. Filter retrieval was attempted in 34 (17.4%) of 195 patients in the preintervention cohort and 66 (32.8%) of 201 patients in the postintervention cohort (P filter retrieval in the preintervention and postintervention cohorts was 60 days (range, 20-428 days) and 107 days (range, 9-600 days), respectively (P = .16). In the preintervention cohort, 49 of 195 (25.1%) patients were lost to follow-up compared with 24 of 201 (11.9%) patients in the postintervention cohort (P filter placement to death, when available. The overall survival for patients whose filters were retrieved was longer compared with the overall survival for patients whose filters were not retrieved (P filter retrieval, two patients (2.5%) suffered from recurrent VTE (n = 1 nonfatal pulmonary embolism; n = 1 deep venous thrombosis). Both patients were treated with anticoagulation without filter replacement. Inferior vena cava filter retrieval rates can be significantly increased in patients with malignant disease with a low rate (2.5%) of recurrent VTE after filter retrieval

  6. Filter-adsorber aging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-02-01

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

  7. Risk Sensitive Filtering with Poisson Process Observations

    International Nuclear Information System (INIS)

    Malcolm, W. P.; James, M. R.; Elliott, R. J.

    2000-01-01

    In this paper we consider risk sensitive filtering for Poisson process observations. Risk sensitive filtering is a type of robust filtering which offers performance benefits in the presence of uncertainties. We derive a risk sensitive filter for a stochastic system where the signal variable has dynamics described by a diffusion equation and determines the rate function for an observation process. The filtering equations are stochastic integral equations. Computer simulations are presented to demonstrate the performance gain for the risk sensitive filter compared with the risk neutral filter

  8. A comparative study of soft sensor design for lipid estimation of microalgal photobioreactor system with experimental validation.

    Science.gov (United States)

    Yoo, Sung Jin; Jung, Dong Hwi; Kim, Jung Hun; Lee, Jong Min

    2015-03-01

    This study examines the applicability of various nonlinear estimators for online estimation of the lipid concentration in microalgae cultivation system. Lipid is a useful bio-product that has many applications including biofuels and bioactives. However, the improvement of lipid productivity using real-time monitoring and control with experimental validation is limited because measurement of lipid in microalgae is a difficult and time-consuming task. In this study, estimation of lipid concentration from other measurable sources such as biomass or glucose sensor was studied. Extended Kalman filter (EKF), unscented Kalman filter (UKF), and particle filter (PF) were compared in various cases for their applicability to photobioreactor systems. Furthermore, simulation studies to identify appropriate types of sensors for estimating lipid were also performed. Based on the case studies, the most effective case was validated with experimental data and found that UKF and PF with time-varying system noise covariance is effective for microalgal photobioreactor system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Formulation of nano-ceramic filters used in separation of heavy metals . Part II: Zirconia ceramic filters

    International Nuclear Information System (INIS)

    Khalil, T.; Labib, Sh.; Abou EI-Nour, F.H.; Abdel-Kbalik, M.

    2007-01-01

    Zirconia ceramic filters are prepared using polymeric sol-gel process. An optimization of synthesis parameters was studied to give cracked free coated nano porous film with high performance quality. Zirconia ceramic filters are characterized to select tbe optimized conditions that give tbe suitable zirconia filter used in heavy metal separation. The ceramic filters were characterized using BET method for surface measurements, mercury porosimeter for pore size distribution analysis and coating thickness measurements, SEM for microstructural studies and atomic absorption spectrophotometer (AAS) for metal analysis. The results indicated that zirconia ceramic filters. show high separation performance for cadmium, cupper, iron, manganese and lead

  10. Online Internal Temperature Estimation for Lithium-Ion Batteries Based on Kalman Filter

    Directory of Open Access Journals (Sweden)

    Jinlei Sun

    2015-05-01

    Full Text Available The battery internal temperature estimation is important for the thermal safety in applications, because the internal temperature is hard to measure directly. In this work, an online internal temperature estimation method based on a simplified thermal model using a Kalman filter is proposed. As an improvement, the influences of entropy change and overpotential on heat generation are analyzed quantitatively. The model parameters are identified through a current pulse test. The charge/discharge experiments under different current rates are carried out on the same battery to verify the estimation results. The internal and surface temperatures are measured with thermocouples for result validation and model construction. The accuracy of the estimated result is validated with a maximum estimation error of around 1 K.

  11. Studies of characteristics of precoating for precoat filter using powdered ion exchange resin as filter aid

    International Nuclear Information System (INIS)

    Adachi, Tetsuro; Sawa, Toshio; Takahashi, Sankichi; Sindo, Toshikazu.

    1987-01-01

    The characteristics of precoating for a precoat filter using powdered ion exchange resin as filter aid were investigated with 1.5 meters long filter elements. The characteristics of precoating (thickness and distribution of precoat layer) were evaluated at various operating conditions. The results showed that the factors controlling them were size of resin flock and ascending velocity of water in the filter vessel. The size of resin flock was affected by reflocculation of resin flock, and operating conditions causing reflocculation were investigated. Consequently, it seemed that reflocculation depended on the maximum value of resin concentration in the filter vessel. In addition, a relation between sedimentation rate of resin flock and ascending velocity in the filter vessel was noticed by simulation of distribution of ascending velocity and effects on characteristics of precoating were evaluated. (author)

  12. Adaptive filtering and change detection

    CERN Document Server

    Gustafsson, Fredrik

    2003-01-01

    Adaptive filtering is a classical branch of digital signal processing (DSP). Industrial interest in adaptive filtering grows continuously with the increase in computer performance that allows ever more conplex algorithms to be run in real-time. Change detection is a type of adaptive filtering for non-stationary signals and is also the basic tool in fault detection and diagnosis. Often considered as separate subjects Adaptive Filtering and Change Detection bridges a gap in the literature with a unified treatment of these areas, emphasizing that change detection is a natural extensi

  13. Experimental evaluation of a new retrievable inferior vena cava filter for protection from acute pulmonary embolism in canine

    International Nuclear Information System (INIS)

    Zhou Chungao; Shi Haibing; Liu Sheng; Wang Chenghu; Liu Hairi; Li Linsun

    2007-01-01

    Objective: To evaluate the validity, safety and feasibility of a new retrieval inferior vena cava filter for the prevention of pulmonary embolism in an animal model. Methods: The model of deep iliofemoral venous thrombosis was established in 12 experimental dogs. In control group(6 experimental dogs), the deep venous thrombosis was made to fall off directly. In experimental group (6 experimental dogs), the deep venous thrombosis was made to fall off with an implanted filter in inferior vena cava. The filter's thrombus-trapping efficacy was evaluated by angiography of pulmonary artery, measurement of the mean pressure of pulmonary artery and arterial oxygen saturation before and after the deep venous thrombus falling off. Results: All filters implanted in the experimental dogs could successfully capture clot coming from deep venous thrombosis. There was no case of pulmonary embolism in experimental groups. On the other hand, pulmonary embolism occurred following the fall of deep venous thrombus in all dogs of control group. Conclusion: The retrievable inferior vena cava filter can effectively prevent from the pulmonary embolism due to falling off of the emboli from deep venous thrombosis. The process of implantation and retrieval is relatively simple and easy. (authors)

  14. Dynamic beam filtering for miscentered patients.

    Science.gov (United States)

    Mao, Andrew; Shyr, William; Gang, Grace J; Stayman, J Webster

    2018-02-01

    Accurate centering of the patient within the bore of a CT scanner takes time and is often difficult to achieve precisely. Patient miscentering can result in significant dose and image noise penalties with the use of traditional bowtie filters. This work describes a system to dynamically position an x-ray beam filter during image acquisition to enable more consistent image performance and potentially lower dose needed for CT imaging. We propose a new approach in which two orthogonal low-dose scout images are used to estimate a parametric model of the object describing its shape, size, and location within the field of view (FOV). This model is then used to compute an optimal filter motion profile by minimizing the variance of the expected detector fluence for each projection. Dynamic filtration was implemented on a cone-beam CT (CBCT) test bench using two different physical filters: 1) an aluminum bowtie and 2) a structured binary filter called a multiple aperture device (MAD). Dynamic filtration performance was compared to a static filter in studies of dose and reconstruction noise as a function of the degree of miscentering of a homogeneous water phantom. Estimated filter trajectories were found to be largely sinusoidal with an amplitude proportional to the amount of miscentering. Dynamic filtration demonstrated an improved ability to keep the spatial distribution of dose and reconstruction noise at baseline levels across varying levels of miscentering, reducing the maximum noise and dose deviation from 53% to 15% and 42% to 14% respectively for the bowtie filter, and 25% to 8% and 24% to 15% respectively for the MAD filter. Dynamic positioning of beam filters during acquisition improves dose utilization and image quality over static filters for miscentered patients. Such dynamic filters relax positioning requirements and have the potential to reduce set-up time and lower dose requirements.

  15. Design of a Balun Bandpass Filter with Asymmetrical Coupled Microstrip Lines

    Science.gov (United States)

    Wang, Xuedao; Wang, Jianpeng; Zhang, Gang; Huang, Feng

    2017-07-01

    A new microstrip coupled-line balun topology and its application to the balun bandpass filter (BPF) with a triple mode response are proposed in this paper. The involved balun structure is composed of two back-to-back quarter-wavelength (λ/4) asymmetrical coupled-line sections. Detailed design formulas based on the asymmetrical coupled-line theory are given to validate the feasibility of the balun. Besides, to obtain filtering performance simultaneously, the balun is then effectively integrated with a pair of triple mode resonators. To demonstrate the design concept of the balun BPF, a prototype operating at 2.4 GHz with the fractional bandwidth (FBW) of about 19.2 % is designed, fabricated, and measured. Results indicate that between the two balanced outputs, the amplitude imbalance is less than 0.3 dB and the phase difference is within 180°±5° inside the whole passband. Both simulated and experimental results are in good agreement.

  16. Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water

    Directory of Open Access Journals (Sweden)

    Md Shafiquzzaman

    2018-02-01

    Full Text Available The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW. The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs. Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480–2000 L/m2/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe, and manganese (Mn. The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m2/d, thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m2/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW.

  17. DESIGN OF DYADIC-INTEGER-COEFFICIENTS BASED BI-ORTHOGONAL WAVELET FILTERS FOR IMAGE SUPER-RESOLUTION USING SUB-PIXEL IMAGE REGISTRATION

    Directory of Open Access Journals (Sweden)

    P.B. Chopade

    2014-05-01

    Full Text Available This paper presents image super-resolution scheme based on sub-pixel image registration by the design of a specific class of dyadic-integer-coefficient based wavelet filters derived from the construction of a half-band polynomial. First, the integer-coefficient based half-band polynomial is designed by the splitting approach. Next, this designed half-band polynomial is factorized and assigned specific number of vanishing moments and roots to obtain the dyadic-integer coefficients low-pass analysis and synthesis filters. The possibility of these dyadic-integer coefficients based wavelet filters is explored in the field of image super-resolution using sub-pixel image registration. The two-resolution frames are registered at a specific shift from one another to restore the resolution lost by CCD array of camera. The discrete wavelet transform (DWT obtained from the designed coefficients is applied on these two low-resolution images to obtain the high resolution image. The developed approach is validated by comparing the quality metrics with existing filter banks.

  18. Decentralized Social Filtering based on Trust

    OpenAIRE

    Olsson, Tomas

    1998-01-01

    This paper describes a decentralised approach to social filtering based on trust between agents in a multiagent system. The social filtering in the proposed approach is built on the interactions between collaborative software agents performing content-based filtering. This means that it uses a mixture of content-based and social filtering and thereby, it takes advantage of both methods.

  19. Automatic segmentation of myocardium at risk from contrast enhanced SSFP CMR: validation against expert readers and SPECT

    International Nuclear Information System (INIS)

    Tufvesson, Jane; Carlsson, Marcus; Aletras, Anthony H.; Engblom, Henrik; Deux, Jean-François; Koul, Sasha; Sörensson, Peder; Pernow, John; Atar, Dan; Erlinge, David; Arheden, Håkan; Heiberg, Einar

    2016-01-01

    Efficacy of reperfusion therapy can be assessed as myocardial salvage index (MSI) by determining the size of myocardium at risk (MaR) and myocardial infarction (MI), (MSI = 1-MI/MaR). Cardiovascular magnetic resonance (CMR) can be used to assess MI by late gadolinium enhancement (LGE) and MaR by either T2-weighted imaging or contrast enhanced SSFP (CE-SSFP). Automatic segmentation algorithms have been developed and validated for MI by LGE as well as for MaR by T2-weighted imaging. There are, however, no algorithms available for CE-SSFP. Therefore, the aim of this study was to develop and validate automatic segmentation of MaR in CE-SSFP. The automatic algorithm applies surface coil intensity correction and classifies myocardial intensities by Expectation Maximization to define a MaR region based on a priori regional criteria, and infarct region from LGE. Automatic segmentation was validated against manual delineation by expert readers in 183 patients with reperfused acute MI from two multi-center randomized clinical trials (RCT) (CHILL-MI and MITOCARE) and against myocardial perfusion SPECT in an additional set (n = 16). Endocardial and epicardial borders were manually delineated at end-diastole and end-systole. Manual delineation of MaR was used as reference and inter-observer variability was assessed for both manual delineation and automatic segmentation of MaR in a subset of patients (n = 15). MaR was expressed as percent of left ventricular mass (%LVM) and analyzed by bias (mean ± standard deviation). Regional agreement was analyzed by Dice Similarity Coefficient (DSC) (mean ± standard deviation). MaR assessed by manual and automatic segmentation were 36 ± 10 % and 37 ± 11 %LVM respectively with bias 1 ± 6 %LVM and regional agreement DSC 0.85 ± 0.08 (n = 183). MaR assessed by SPECT and CE-SSFP automatic segmentation were 27 ± 10 %LVM and 29 ± 7 %LVM respectively with bias 2 ± 7 %LVM. Inter-observer variability was 0 ± 3 %LVM for manual delineation and

  20. How evidence-based are the recommendations in evidence-based guidelines?

    Directory of Open Access Journals (Sweden)

    Finlay A McAlister

    2007-08-01

    Full Text Available BACKGROUND: Treatment recommendations for the same condition from different guideline bodies often disagree, even when the same randomized controlled trial (RCT evidence is cited. Guideline appraisal tools focus on methodology and quality of reporting, but not on the nature of the supporting evidence. This study was done to evaluate the quality of the evidence (based on consideration of its internal validity, clinical relevance, and applicability underlying therapy recommendations in evidence-based clinical practice guidelines. METHODS AND FINDINGS: A cross-sectional analysis of cardiovascular risk management recommendations was performed for three different conditions (diabetes mellitus, dyslipidemia, and hypertension from three pan-national guideline panels (from the United States, Canada, and Europe. Of the 338 treatment recommendations in these nine guidelines, 231 (68% cited RCT evidence but only 105 (45% of these RCT-based recommendations were based on high-quality evidence. RCT-based evidence was downgraded most often because of reservations about the applicability of the RCT to the populations specified in the guideline recommendation (64/126 cases, 51% or because the RCT reported surrogate outcomes (59/126 cases, 47%. CONCLUSIONS: The results of internally valid RCTs may not be applicable to the populations, interventions, or outcomes specified in a guideline recommendation and therefore should not always be assumed to provide high-quality evidence for therapy recommendations.

  1. Input filter compensation for switching regulators

    Science.gov (United States)

    Lee, F. C.; Kelkar, S. S.

    1982-01-01

    The problems caused by the interaction between the input filter, output filter, and the control loop are discussed. The input filter design is made more complicated because of the need to avoid performance degradation and also stay within the weight and loss limitations. Conventional input filter design techniques are then dicussed. The concept of pole zero cancellation is reviewed; this concept is the basis for an approach to control the peaking of the output impedance of the input filter and thus mitigate some of the problems caused by the input filter. The proposed approach for control of the peaking of the output impedance of the input filter is to use a feedforward loop working in conjunction with feedback loops, thus forming a total state control scheme. The design of the feedforward loop for a buck regulator is described. A possible implementation of the feedforward loop design is suggested.

  2. Evaluation of HEPA filter service life

    International Nuclear Information System (INIS)

    Fretthold, J.K.; Stithem, A.R.

    1997-01-01

    Rocky Flats Environmental Technology Site (RFETS), has approximately 10,000 High Efficiency Particulate Air (HEPA) Filters installed in a variety of filter plenums. These ventilation/filtration plenum systems are used to control the release of airborne particulate contaminates to the environment during normal operations and potential accidents. This report summarizes the results of destructive and non-destructive tests on HEPA filters obtained from a wide variety of ages and service conditions. These tests were performed to determine an acceptable service life criteria for HEPA filters used at Rocky Flats Environmental Technology Site (RFETS). A total of 140 filters of various ages (1972 to 1996) and service history (new, aged unused, used) were tested. For the purpose of this report, filter age from manufacture date/initial test date to the current sample date was used, as opposed to the actual time a filter was installed in an operating system

  3. Flat microwave photonic filter based on hybrid of two filters

    International Nuclear Information System (INIS)

    Qi, Chunhui; Pei, Li; Ning, Tigang; Li, Jing; Gao, Song

    2010-01-01

    A new microwave photonic filter (MPF) hybrid of two filters that can realize both multiple taps and a flat bandpass or bandstop response is presented. Based on the phase character of a Mach–Zehnder modulator (MZM), a two taps finite impulse response (FIR) filter is obtained as the first part. The second part is obtained by taking full advantage of the wavelength selectivity of the fiber Bragg grating (FBG) and the gain of a erbium-doped fiber (EDF). Combining the two filters, the flat bandpass or bandstop response is realized by changing the coupler's factor k, the reflectivity of FBG1 R 1 or the gain of the EDF g. Optimizing the system parameters, a flat bandpass response with amplitude depth of more than 45 dB is obtained at k = 0.5, R 1 = 0.33, g = 10, and a flat bandstop response is also obtained at k = 0.4, R 1 = 0.5, g = 2. In addition, the free-spectral range (FSR) can be controlled by changing the length of the EDF and the length difference between two MZMs. The method is proved feasible by some experiments. Such a method offers realistic solutions to support future radio-frequency (RF) optical communication systems

  4. Ion exchange nonwoven fabric chemical filter. 2

    International Nuclear Information System (INIS)

    Sekiguchi, Hideaki

    2000-01-01

    This report outlined the characteristics of EPIX filter and its complex with activated carbon to eliminate organic compounds from solvent. Elimination performance of this filter was determined using an ion chromatographic analyzer. EPIX filter showed high performance to eliminate trace amount of ionic compounds. The rate of elimination was both 99% or more for NH 3 and SO 2 in an early phase of filtration. Release of dust as well as impurities was significantly reduced by the use of EPIX filter. Gases once adsorbed on the filter were not released even at an elevated temperature of atmosphere. Combined use of non-woven fabrics was possible. For EPIX filter, there are three kinds; strong acid cation exchange filter and strong/weak basic anion filters. The weak basic anion filter has been applied to the conventional apparatus in wafer makers because the filter was very effective for selective boron trapping. When polyethyleneterephthalate was used as the base polymer, radical groups produced on the polymer were co-polymerized with monomer substances. The lifetime of filter was estimated on a base of gas concentration and wind velocity to determine the time to replace with a new one. Furthermore, the loss of pressure became less than a half when EPIX filter was used. (M.N.)

  5. Liquid filter for liquids containing radioactive materials

    International Nuclear Information System (INIS)

    Rohleder, N.; Schwarz, F.

    1986-01-01

    A device for filtering radioactive liquids loaded with solids is described, which has a pressure-resistant housing with a lid and an incomer for the turbid liquid and a collecting space and drain for the filtrate at the bottom of the housing. A filter cartridge is present in this housing. Such a filtering device must be suitable for use in nuclear plants, must be easy to replace by remote control and must minimise the carrying over of radioactive particles. This problem should be solved by the filter cartridge consisting of a large number of horizontal filter plates stacked above one another, which carry a deep layer filter material acting in the sub-micron range. The turbid liquid runs into the centre of the stack of filter plates via a vertical central duct. The intermediate spaces between the filter places are connected to this central duct via the layer of filter material. The filter plates are sealed against one another on the outer circumference and have radial drain openings for the filtrate on the outside. The central duct is sealed at the lower end by a plate. When the filter cartridge is replaced, the radioactive waste in the filter cartridge remains safely enclosed and can be conditioned in suitable containers. (orig.) [de

  6. Factors Influencing HEPA Filter Performance

    International Nuclear Information System (INIS)

    Parsons, M.S.; Waggoner, Ch.A.

    2009-01-01

    Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

  7. Computerized tomographic scanner with shaped radiation filter

    International Nuclear Information System (INIS)

    Carlson, R.W.; Walters, R.G.

    1981-01-01

    The invention comprises a shaped filter and a filter correction circuitry for computerized tomographic scanners. The shaped filter is a generally u-shaped block of filter material which is adapted to be mounted between the source of radiation and the scan circle. The u-shaped block has a parabolic recess. The filter material may be beryllium, aluminum, sulphur, calcium, titanium, erbium, copper, and compounds including oxides and alloys thereof. The filter correction circuit comprises a first filter correction profile adding circuit for adding a first scaler valve to each intensity valve in a data line. The data line is operated on by a beam hardness correction polynomial. After the beam hardness polynomial correction operation, a second filter correction circuit adds a second filter correction profile consisting of a table of scalor values, one corresponding to each intensity reading in the data line

  8. A quantum extended Kalman filter

    International Nuclear Information System (INIS)

    Emzir, Muhammad F; Woolley, Matthew J; Petersen, Ian R

    2017-01-01

    In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements. (paper)

  9. A quantum extended Kalman filter

    Science.gov (United States)

    Emzir, Muhammad F.; Woolley, Matthew J.; Petersen, Ian R.

    2017-06-01

    In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements.

  10. Novel Control Strategy for VSI and CSI Active Filters and Comparing These Two Types of Filters

    Directory of Open Access Journals (Sweden)

    Gholam Reza Arab

    2014-10-01

    Full Text Available Recently to eliminate the harmonics and improve the power factor of the power networks, much attention has been attracted to active filters. The advantages of these filters are lower volume and their better compensating characteristics than the passive filters. In conventional sliding mode controllers, the source current waveform is fluctuated in near to zero values. In this paper, using a new sliding technique, lower Total Harmonic Distortion (THD in source current is obtained and the current waveform is improved. As well as, two novel control strategies for two types of active filters, VSI and CSI is proposed and then these two types of filters are compared to reduce THD value of source current.The proposed controlled strategies are simulated by MATLAB/Simulink. The Simulation results confirm that the proposed strategies reduce the THD of source current more than other strategies, and active filter based on CSI has a better performance than active filter based on VSI with a dead time area (for avoiding short circuit of the source in high powers.

  11. A Comparison of Retrievability: Celect versus Option Filter.

    Science.gov (United States)

    Ryu, Robert K; Desai, Kush; Karp, Jennifer; Gupta, Ramona; Evans, Alan Emerson; Rajeswaran, Shankar; Salem, Riad; Lewandowski, Robert J

    2015-06-01

    To compare the retrievability of 2 potentially retrievable inferior vena cava filter devices. A retrospective, institutional review board-approved study of Celect (Cook, Inc, Bloomington, Indiana) and Option (Rex Medical, Conshohocken, Pennsylvania) filters was conducted over a 33-month period at a single institution. Fluoroscopy time, significant filter tilt, use of adjunctive retrieval technique, and strut perforation in the inferior vena cava were recorded on retrieval. Fisher exact test and Mann-Whitney-Wilcoxon test were used for comparison. There were 99 Celect and 86 Option filters deployed. After an average of 2.09 months (range, 0.3-7.6 mo) and 1.94 months (range, 0.47-9.13 mo), respectively, 59% (n = 58) of patients with Celect filters and 74.7% (n = 65) of patients with Option filters presented for filter retrieval. Retrieval failure rates were 3.4% for Celect filters versus 7.7% for Option filters (P = .45). Median fluoroscopy retrieval times were 4.25 minutes for Celect filters versus 6 minutes for Option filters (P = .006). Adjunctive retrieval techniques were used in 5.4% of Celect filter retrievals versus 18.3% of Option filter retrievals (P = .045). The incidence of significant tilting was 8.9% for Celect filters versus 16.7% for Option filters (P = .27). The incidence of strut perforation was 43% for Celect filters versus 0% for Option filters (P Option filters were not significantly different. However, retrieval of the Option filter required a significantly increased amount of fluoroscopy time compared with the Celect filter, and there was a significantly greater usage of adjunctive retrieval techniques for the Option filter. The Celect filter had a significantly higher rate of strut perforation. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

  12. Linear Regression Based Real-Time Filtering

    Directory of Open Access Journals (Sweden)

    Misel Batmend

    2013-01-01

    Full Text Available This paper introduces real time filtering method based on linear least squares fitted line. Method can be used in case that a filtered signal is linear. This constraint narrows a band of potential applications. Advantage over Kalman filter is that it is computationally less expensive. The paper further deals with application of introduced method on filtering data used to evaluate a position of engraved material with respect to engraving machine. The filter was implemented to the CNC engraving machine control system. Experiments showing its performance are included.

  13. Kernel-based noise filtering of neutron detector signals

    International Nuclear Information System (INIS)

    Park, Moon Ghu; Shin, Ho Cheol; Lee, Eun Ki

    2007-01-01

    This paper describes recently developed techniques for effective filtering of neutron detector signal noise. In this paper, three kinds of noise filters are proposed and their performance is demonstrated for the estimation of reactivity. The tested filters are based on the unilateral kernel filter, unilateral kernel filter with adaptive bandwidth and bilateral filter to show their effectiveness in edge preservation. Filtering performance is compared with conventional low-pass and wavelet filters. The bilateral filter shows a remarkable improvement compared with unilateral kernel and wavelet filters. The effectiveness and simplicity of the unilateral kernel filter with adaptive bandwidth is also demonstrated by applying it to the reactivity measurement performed during reactor start-up physics tests

  14. Progress towards the use of disposable filters

    International Nuclear Information System (INIS)

    Macphail, I.

    1979-08-01

    Thermally degradable materials have been evaluated for service in HEPA filter units used to filter gases from active plants. The motivation was to reduce the bulk storage problems of contaminated filters by thermal decomposition to gaseous products and a solid residue substantially comprised of the filtered particulates. It is shown that while there are no commercially available alternatives to the glass fibre used in the filter medium, it would be feasible to manufacture the filter case and spacers from materials which could be incinerated. Operating temperatures, costs and the type of residues for disposal are discussed for filter case materials. (U.K.)

  15. Isolated prospective confabulation in Wernicke-Korsakoff syndrome: a case for reality filtering.

    Science.gov (United States)

    Schnider, Armin; Nahum, Louis; Pignat, Jean-Michel; Leemann, Béatrice; Lövblad, Karl-Olof; Wissmeyer, Michael; Ptak, Radek

    2013-01-01

    A 57-year-old man suffered severe amnesia and disorientation, accompanied by content-specific confabulation, due to an alcoholic Wernicke-Korsakoff syndrome. For months, he was deeply concerned about a single obligation that he thought he had to respond to, but which he had already assumed 20 years previously. This monothematic, prospective confabulation was associated with failures of reality filtering as previously documented in behaviorally spontaneous confabulation and disorientation: the patient failed to suppress the interference of currently irrelevant memories and to abandon anticipations that were no longer valid (impaired extinction capacity). Magnetic resonance imaging showed damage to the mamillary bodies and the dorsomedial thalamic nucleus. Positron emission tomography (FDG-PET) showed extended orbitofrontal hypometabolism. We suggest that isolated prospective confabulation shares the core feature (acts and thoughts based on currently irrelevant memory), mechanism (failure of reality filtering), and anatomical basis (orbitofrontal dysfunction) with behaviorally spontaneous confabulations.

  16. Manipulation Robustness of Collaborative Filtering

    OpenAIRE

    Benjamin Van Roy; Xiang Yan

    2010-01-01

    A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions and hence have become targets of manipulation by unscrupulous vendors. We demonstrate that nearest neighbors algorithms, which are widely used in commercial systems, are highly susceptible to manipulation and introduce new collaborative filtering algorithms that are relatively robust.

  17. Effect of Intake Air Filter Condition on Vehicle Fuel Economy

    Energy Technology Data Exchange (ETDEWEB)

    Norman, Kevin M [ORNL; Huff, Shean P [ORNL; West, Brian H [ORNL

    2009-02-01

    The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency (EPA) jointly maintain a fuel economy website (www.fueleconomy.gov), which helps fulfill their responsibility under the Energy Policy Act of 1992 to provide accurate fuel economy information [in miles per gallon (mpg)] to consumers. The site provides information on EPA fuel economy ratings for passenger cars and light trucks from 1985 to the present and other relevant information related to energy use such as alternative fuels and driving and vehicle maintenance tips. In recent years, fluctuations in the price of crude oil and corresponding fluctuations in the price of gasoline and diesel fuels have renewed interest in vehicle fuel economy in the United States. (User sessions on the fuel economy website exceeded 20 million in 2008 compared to less than 5 million in 2004 and less than 1 million in 2001.) As a result of this renewed interest and the age of some of the references cited in the tips section of the website, DOE authorized the Oak Ridge National Laboratory (ORNL) Fuels, Engines, and Emissions Research Center (FEERC) to initiate studies to validate and improve these tips. This report documents a study aimed specifically at the effect of engine air filter condition on fuel economy. The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested. Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in

  18. Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

    Directory of Open Access Journals (Sweden)

    Bruderek Juliane

    2008-10-01

    Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

  19. Open source deformable image registration system for treatment planning and recurrence CT scans

    DEFF Research Database (Denmark)

    Zukauskaite, Ruta; Brink, Carsten; Hansen, Christian Rønn

    2016-01-01

    manually contoured eight anatomical regions-of-interest (ROI) twice on pCT and once on rCT. METHODS: pCT and rCT images were deformably registered using the open source software elastix. Mean surface distance (MSD) and Dice similarity coefficient (DSC) between contours were used for validation of DIR...

  20. The Development of a Microbial Challenge Test with Acholeplasma laidlawii To Rate Mycoplasma-Retentive Filters by Filter Manufacturers.

    Science.gov (United States)

    Folmsbee, Martha; Lentine, Kerry Roche; Wright, Christine; Haake, Gerhard; Mcburnie, Leesa; Ashtekar, Dilip; Beck, Brian; Hutchison, Nick; Okhio-Seaman, Laura; Potts, Barbara; Pawar, Vinayak; Windsor, Helena

    2014-01-01

    Mycoplasma are bacteria that can penetrate 0.2 and 0.22 μm rated sterilizing-grade filters and even some 0.1 μm rated filters. Primary applications for mycoplasma filtration include large scale mammalian and bacterial cell culture media and serum filtration. The Parenteral Drug Association recognized the absence of standard industry test parameters for testing and classifying 0.1 μm rated filters for mycoplasma clearance and formed a task force to formulate consensus test parameters. The task force established some test parameters by common agreement, based upon general industry practices, without the need for additional testing. However, the culture medium and incubation conditions, for generating test mycoplasma cells, varied from filter company to filter company and was recognized as a serious gap by the task force. Standardization of the culture medium and incubation conditions required collaborative testing in both commercial filter company laboratories and in an Independent laboratory (Table I). The use of consensus test parameters will facilitate the ultimate cross-industry goal of standardization of 0.1 μm filter claims for mycoplasma clearance. However, it is still important to recognize filter performance will depend on the actual conditions of use. Therefore end users should consider, using a risk-based approach, whether process-specific evaluation of filter performance may be warranted for their application. Mycoplasma are small bacteria that have the ability to penetrate sterilizing-grade filters. Filtration of large-scale mammalian and bacterial cell culture media is an example of an industry process where effective filtration of mycoplasma is required. The Parenteral Drug Association recognized the absence of industry standard test parameters for evaluating mycoplasma clearance filters by filter manufacturers and formed a task force to formulate such a consensus among manufacturers. The use of standardized test parameters by filter manufacturers

  1. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  2. 2P2IHUNTER: a tool for filtering orthosteric protein–protein interaction modulators via a dedicated support vector machine

    Science.gov (United States)

    Hamon, Véronique; Bourgeas, Raphael; Ducrot, Pierre; Theret, Isabelle; Xuereb, Laura; Basse, Marie Jeanne; Brunel, Jean Michel; Combes, Sebastien; Morelli, Xavier; Roche, Philippe

    2014-01-01

    Over the last 10 years, protein–protein interactions (PPIs) have shown increasing potential as new therapeutic targets. As a consequence, PPIs are today the most screened target class in high-throughput screening (HTS). The development of broad chemical libraries dedicated to these particular targets is essential; however, the chemical space associated with this ‘high-hanging fruit’ is still under debate. Here, we analyse the properties of 40 non-redundant small molecules present in the 2P2I database (http://2p2idb.cnrs-mrs.fr/) to define a general profile of orthosteric inhibitors and propose an original protocol to filter general screening libraries using a support vector machine (SVM) with 11 standard Dragon molecular descriptors. The filtering protocol has been validated using external datasets from PubChem BioAssay and results from in-house screening campaigns. This external blind validation demonstrated the ability of the SVM model to reduce the size of the filtered chemical library by eliminating up to 96% of the compounds as well as enhancing the proportion of active compounds by up to a factor of 8. We believe that the resulting chemical space identified in this paper will provide the scientific community with a concrete support to search for PPI inhibitors during HTS campaigns. PMID:24196694

  3. Analysis of the implementation of a sand bed type filter for the venting of a nuclear power plant

    International Nuclear Information System (INIS)

    Cuevas V, D.; Sainz M, E.; Ortiz V, J.

    2017-09-01

    The filtered venting of the containment has been adopted in European countries to mitigate the consequences derived from the excess pressure of the containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter is placed in the path of the same, so various types of filters are used to trap the fission products. The containment venting filters currently installed use different filtering technologies that involve more than one medium. Those who use water as the first stage of filtration are called wet systems, are equipped with additional stages to eliminate water drops and emissions of fine aerosols, and may even be equipped with an element that contains certain means of absorption for the gaseous iodine species filtration. Other designs, based on deep bed filtration as the main retention stage, called dry filters; use metal fiber, ceramic or sand filtration media to trap aerosols. The present work evaluates the hydraulic characteristics of the sand bed type filter designed by EDF as a candidate to be installed in the containment of the BWR Mark II (primary containment type of the Laguna Verde nuclear power plant). The evaluation of the sand bed filter was performed using the OpenFOAM open source software package. Models of each zone of the filtering device were generated and by means of a series of parametric calculations of computational fluid mechanics, the relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow and pressure fields and velocity under different operating conditions. On the other hand, the validation of the sand bed filter model was made when comparing the results of experimental tests carried out in a sand column of the PITEAS program (1985-1986) against the simulation in OpenFOAM. The results obtained are very close to those obtained experimentally. (Author)

  4. Generalized design of high performance shunt active power filter with output LCL filter

    DEFF Research Database (Denmark)

    Tang, Yi; Loh, Poh Chiang; Wang, Peng

    2012-01-01

    parameters, interactions between resonance damping and harmonic compensation, bandwidth design of the closed-loop system, and active damping implementation with fewer current sensors. These described design concerns, together with their generalized design procedure, are applied to an analytical example......This paper concentrates on the design, control, and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate for harmonic currents produced by nonlinear loads in a three-phase three-wire power system. With an LCL filter added at its output...

  5. Technical task plan for testing filter box sorbent-paint filter test

    International Nuclear Information System (INIS)

    Kilpatrick, L.L.

    1993-01-01

    At the Savannah River Plant, High Level Waste Engineering (HLWE) asked Interim Waste Technology (IWT) to choose and test a sorbent to add to the ITP filter box that meets the EPA requirement for land disposal of containerized liquid hazardous wastes per Paint Filter Liquids (PFL) test method 9095. This report outlines the process to be used in accomplishing this task

  6. Robust filtering for dynamic compensation of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Peng, Xingjie; Li, Qing; Zhao, Wenbo; Gong, Helin; Wang, Kan

    2014-01-01

    Highlights: • Three dynamic compensation methods based on robust filtering theory are proposed. • Filter design problems are converted into linear matrix inequality problems. • Rhodium and Vanadium self-powered neutron detectors are used to validate the use of these three dynamic compensation methods. • The numerical simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression. - Abstract: Self-powered neutron detectors (SPNDs), which are widely used in nuclear reactors to obtain core neutron flux distribution, are accurate at steady state but respond slowly to changes in neutron flux. Dynamic compensation methods are required to improve the response speed of the SPNDs and make it possible to apply the SPNDs for core monitoring and surveillance. In this paper, three digital dynamic compensation methods are proposed. All the three methods are based on the convex optimization framework using linear matrix inequalities (LMIs). The simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression

  7. Filter system for purifying gas or air streams

    International Nuclear Information System (INIS)

    Ohlmeyer, M.; Wilhelm, J.

    1981-01-01

    A filter system is provided for purifying a gas stream by means of flowable or tricklable contact filter material, wherein the stream flows through the filter material and the filter material forms a movable bed. The system contains a filter chamber through which the filter material can flow and which is provided with an inlet opening and an outlet opening for the filter material between which the filter material is conveyed by gravity. The filter system includes deflection means for deflecting the stream , after a first passage of the stream through the filter bed to charge the filter bed for a first time, to a position above where the stream first passed through the filter bed and for conducting the stream at least once again transversely through the filter bed above the first charge so that the filter bed is charged a second time. The filter chamber contains a first opening where the stream enters the filter bed for the first time and is aligned with the deflection means, and a second opening aligned with the deflection means and above the first opening. The second opening is located where the stream leaves the filter bed for the second time, with a partial quantity of the gas stream being able to pass directly through the filter bed from the first opening to the second opening without going through the deflection means. The distance between the upper edge of the first opening and the lower edge of the second opening is at least twice the thickness of the filter chamber

  8. Designing H-shaped micromechanical filters

    International Nuclear Information System (INIS)

    Arhaug, O P; Soeraasen, O

    2006-01-01

    This paper investigates the design constraints and possibilities given when designing a micromechanical band pass filter for intermediate frequencies (e.g. 10 MHz). The class of filters are based on coupled clamped-clamped beams constituting an H-shaped structure. A primary beam can electrostatically be activated in one of its different harmonic modes, setting the filter center frequency. The motion is transferred to an accompanying beam of equal dimensions by a mechanical coupling beam. The placement or coupling points of the quarterwavelength coupling beam which connects the vertically resonating beams is critical with respect to the bandwidth of the filters. Of special concern has been to investigate realistic dimensions allowing the filters to be processed by an actual foundry process and to find out how the choice of materials and actual dimensions would affect the performance

  9. Semiconductor cleaning liquid delivery system and its filter; Handotaiyo seijo yakueki kyokyu system to filter

    Energy Technology Data Exchange (ETDEWEB)

    Saito, T. [Kanto Chemical Co. Inc., Tokyo (Japan); Hayama, H.; Sakka, T. [Nitto Denko Corp., Osaka (Japan)

    1994-11-30

    Most of chemicals used for producing semiconductors are supplied automatically by a chemical delivery system to production devices. This paper explains the current status and the trends of the system. This system supplies the chemicals in the order of a tank lorry, a storage tank, a supply tank, a filter and a production device, and the transfer is performed receiving a supply signal from the supply tank and the production device. The transfer may be done through a dilution equipment. Filters currently used have membrane pore sizes of 0.2 to 0.1 microns as prefilters, and 0.1 to 0.05 microns as final filters. Chemicals used are diverse and can be divided into acid-, alkaline-, and solvent-based groups. Fluorine resin filters are used for acid- and alkaline-resistant applications, and SUS/fluorine resin filters for solvent-resistant applications. Use of large-sized filters of element construction with a membrane area of 1 m{sup 2} class is increasing recently in addition to selection from a performance viewpoint, including particle removing performance. 9 figs., 7 tabs.

  10. Spatial filter issues

    International Nuclear Information System (INIS)

    Murray, J.E.; Estabrook, K.G.; Milam, D.; Sell, W.D.; Van Wonterghem, R.M.; Feil, M.D.; Rubenchick, A.M.

    1996-01-01

    Experiments and calculations indicate that the threshold pressure in spatial filters for distortion of a transmitted pulse scales approximately as I O.2 and (F number-sign) 2 over the intensity range from 10 14 to 2xlO 15 W/CM 2 . We also demonstrated an interferometric diagnostic that will be used to measure the scaling relationships governing pinhole closure in spatial filters

  11. Human attention filters for single colors

    Science.gov (United States)

    Sun, Peng; Chubb, Charles; Wright, Charles E.; Sperling, George

    2016-01-01

    The visual images in the eyes contain much more information than the brain can process. An important selection mechanism is feature-based attention (FBA). FBA is best described by attention filters that specify precisely the extent to which items containing attended features are selectively processed and the extent to which items that do not contain the attended features are attenuated. The centroid-judgment paradigm enables quick, precise measurements of such human perceptual attention filters, analogous to transmission measurements of photographic color filters. Subjects use a mouse to locate the centroid—the center of gravity—of a briefly displayed cloud of dots and receive precise feedback. A subset of dots is distinguished by some characteristic, such as a different color, and subjects judge the centroid of only the distinguished subset (e.g., dots of a particular color). The analysis efficiently determines the precise weight in the judged centroid of dots of every color in the display (i.e., the attention filter for the particular attended color in that context). We report 32 attention filters for single colors. Attention filters that discriminate one saturated hue from among seven other equiluminant distractor hues are extraordinarily selective, achieving attended/unattended weight ratios >20:1. Attention filters for selecting a color that differs in saturation or lightness from distractors are much less selective than attention filters for hue (given equal discriminability of the colors), and their filter selectivities are proportional to the discriminability distance of neighboring colors, whereas in the same range hue attention-filter selectivity is virtually independent of discriminabilty. PMID:27791040

  12. The Use of Nonlinear Constitutive Equations to Evaluate Draw Resistance and Filter Ventilation

    Directory of Open Access Journals (Sweden)

    Eitzinger B

    2014-12-01

    Full Text Available This study investigates by nonlinear constitutive equations the influence of tipping paper, cigarette paper, filter, and tobacco rod on the degree of filter ventilation and draw resistance. Starting from the laws of conservation, the path to the theory of fluid dynamics in porous media and Darcy's law is reviewed and, as an extension to Darcy's law, two different nonlinear pressure drop-flow relations are proposed. It is proven that these relations are valid constitutive equations and the partial differential equations for the stationary flow in an unlit cigarette covering anisotropic, inhomogeneous and nonlinear behaviour are derived. From these equations a system of ordinary differential equations for the one-dimensional flow in the cigarette is derived by averaging pressure and velocity over the cross section of the cigarette. By further integration, the concept of an electrical analog is reached and discussed in the light of nonlinear pressure drop-flow relations. By numerical calculations based on the system of ordinary differential equations, it is shown that the influence of nonlinearities cannot be neglected because variations in the degree of filter ventilation can reach up to 20% of its nominal value.

  13. Nonlinear spatio-temporal filtering of dynamic PET data using a four-dimensional Gaussian filter and expectation-maximization deconvolution

    International Nuclear Information System (INIS)

    Floberg, J M; Holden, J E

    2013-01-01

    We introduce a method for denoising dynamic PET data, spatio-temporal expectation-maximization (STEM) filtering, that combines four-dimensional Gaussian filtering with EM deconvolution. The initial Gaussian filter suppresses noise at a broad range of spatial and temporal frequencies and EM deconvolution quickly restores the frequencies most important to the signal. We aim to demonstrate that STEM filtering can improve variance in both individual time frames and in parametric images without introducing significant bias. We evaluate STEM filtering with a dynamic phantom study, and with simulated and human dynamic PET studies of a tracer with reversible binding behaviour, [C-11]raclopride, and a tracer with irreversible binding behaviour, [F-18]FDOPA. STEM filtering is compared to a number of established three and four-dimensional denoising methods. STEM filtering provides substantial improvements in variance in both individual time frames and in parametric images generated with a number of kinetic analysis techniques while introducing little bias. STEM filtering does bias early frames, but this does not affect quantitative parameter estimates. STEM filtering is shown to be superior to the other simple denoising methods studied. STEM filtering is a simple and effective denoising method that could be valuable for a wide range of dynamic PET applications. (paper)

  14. Filtering observations without the initial guess

    Science.gov (United States)

    Chin, T. M.; Abbondanza, C.; Gross, R. S.; Heflin, M. B.; Parker, J. W.; Soja, B.; Wu, X.

    2017-12-01

    Noisy geophysical observations sampled irregularly over space and time are often numerically "analyzed" or "filtered" before scientific usage. The standard analysis and filtering techniques based on the Bayesian principle requires "a priori" joint distribution of all the geophysical parameters of interest. However, such prior distributions are seldom known fully in practice, and best-guess mean values (e.g., "climatology" or "background" data if available) accompanied by some arbitrarily set covariance values are often used in lieu. It is therefore desirable to be able to exploit efficient (time sequential) Bayesian algorithms like the Kalman filter while not forced to provide a prior distribution (i.e., initial mean and covariance). An example of this is the estimation of the terrestrial reference frame (TRF) where requirement for numerical precision is such that any use of a priori constraints on the observation data needs to be minimized. We will present the Information Filter algorithm, a variant of the Kalman filter that does not require an initial distribution, and apply the algorithm (and an accompanying smoothing algorithm) to the TRF estimation problem. We show that the information filter allows temporal propagation of partial information on the distribution (marginal distribution of a transformed version of the state vector), instead of the full distribution (mean and covariance) required by the standard Kalman filter. The information filter appears to be a natural choice for the task of filtering observational data in general cases where prior assumption on the initial estimate is not available and/or desirable. For application to data assimilation problems, reduced-order approximations of both the information filter and square-root information filter (SRIF) have been published, and the former has previously been applied to a regional configuration of the HYCOM ocean general circulation model. Such approximation approaches are also briefed in the

  15. Characteristics of Quoit filter, a digital filter developed for the extraction of circumscribed shadows, and its applications to mammograms

    International Nuclear Information System (INIS)

    Isobe, Yoshiaki; Ohkubo, Natsumi; Yamamoto, Shinji; Toriwaki, Jun-ichiro; Kobatake, Hidefumi.

    1993-01-01

    This paper presents a newly developed filter called Quoit filter, which detects circumscribed shadows (concentric circular isolated image), like typical cancer regions. This Quoit filter is based on the mathematical morphology and is found to have interesting facts as follows. (1) Output of this filter can be analytically expressible when an input image is assumed to be a concentric circular model (output is expectable for typical inputs). (2) This filter has an ability to reconstruct original isolated models mentioned in (1) selectively, when this filter is applied sequentially twice. This filter was tested on the detection of cancer regions in X-ray mammograms, and for 12 cancer mammograms, this filter achieved a true-positive cancer detection rate of 100 %. (author)

  16. Application of square-root filtering for spacecraft attitude control

    Science.gov (United States)

    Sorensen, J. A.; Schmidt, S. F.; Goka, T.

    1978-01-01

    Suitable digital algorithms are developed and tested for providing on-board precision attitude estimation and pointing control for potential use in the Landsat-D spacecraft. These algorithms provide pointing accuracy of better than 0.01 deg. To obtain necessary precision with efficient software, a six state-variable square-root Kalman filter combines two star tracker measurements to update attitude estimates obtained from processing three gyro outputs. The validity of the estimation and control algorithms are established, and the sensitivity of their performance to various error sources and software parameters are investigated by detailed digital simulation. Spacecraft computer memory, cycle time, and accuracy requirements are estimated.

  17. A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang

    2016-01-01

    Passive trap filters are widely used in high power Voltage Source Inverters (VSI) for the switching harmonic attenuation. The usage of the passive trap filters requires clustered and fixed switching harmonic spectrum, which is not the case for low pulse-ratio or Variable Switching Frequency (VSF...... current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output...... impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control...

  18. Non-linear DSGE Models, The Central Difference Kalman Filter, and The Mean Shifted Particle Filter

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller

    This paper shows how non-linear DSGE models with potential non-normal shocks can be estimated by Quasi-Maximum Likelihood based on the Central Difference Kalman Filter (CDKF). The advantage of this estimator is that evaluating the quasi log-likelihood function only takes a fraction of a second....... The second contribution of this paper is to derive a new particle filter which we term the Mean Shifted Particle Filter (MSPFb). We show that the MSPFb outperforms the standard Particle Filter by delivering more precise state estimates, and in general the MSPFb has lower Monte Carlo variation in the reported...

  19. Side loading filter apparatus

    International Nuclear Information System (INIS)

    Reynolds, K.E.

    1981-01-01

    A side loading filter chamber for use with radioactive gases is described. The equipment incorporates an inexpensive, manually operated, mechanism for aligning filter units with a number of laterally spaced wall openings and for removing the units from the chamber. (U.K.)

  20. An Efficient State–Parameter Filtering Scheme Combining Ensemble Kalman and Particle Filters

    KAUST Repository

    Ait-El-Fquih, Boujemaa

    2017-12-11

    This work addresses the state-parameter filtering problem for dynamical systems with relatively large-dimensional state and low-dimensional parameters\\' vector. A Bayesian filtering algorithm combining the strengths of the particle filter (PF) and the ensemble Kalman filter (EnKF) is proposed. At each assimilation cycle of the proposed EnKF-PF, the PF is first used to sample the parameters\\' ensemble followed by the EnKF to compute the state ensemble conditional on the resulting parameters\\' ensemble. The proposed scheme is expected to be more efficient than the traditional state augmentation techniques, which suffer from the curse of dimensionality and inconsistency that is particularly pronounced when the state is a strongly nonlinear function of the parameters. In the new scheme, the EnKF and PF interact via their ensembles\\' members, in contrast with the recently introduced two-stage EnKF-PF (TS-EnKF-PF), which exchanges point estimates between EnKF and PF while requiring almost double the computational load. Numerical experiments are conducted with the Lorenz-96 model to assess the behavior of the proposed filter and to evaluate its performances against the joint PF, joint EnKF, and TS-EnKF-PF. Numerical results suggest that the EnKF-PF performs best in all tested scenarios. It was further found to be more robust, successfully estimating both state and parameters in different sensitivity experiments.

  1. An Efficient State–Parameter Filtering Scheme Combining Ensemble Kalman and Particle Filters

    KAUST Repository

    Ait-El-Fquih, Boujemaa; Hoteit, Ibrahim

    2017-01-01

    This work addresses the state-parameter filtering problem for dynamical systems with relatively large-dimensional state and low-dimensional parameters' vector. A Bayesian filtering algorithm combining the strengths of the particle filter (PF) and the ensemble Kalman filter (EnKF) is proposed. At each assimilation cycle of the proposed EnKF-PF, the PF is first used to sample the parameters' ensemble followed by the EnKF to compute the state ensemble conditional on the resulting parameters' ensemble. The proposed scheme is expected to be more efficient than the traditional state augmentation techniques, which suffer from the curse of dimensionality and inconsistency that is particularly pronounced when the state is a strongly nonlinear function of the parameters. In the new scheme, the EnKF and PF interact via their ensembles' members, in contrast with the recently introduced two-stage EnKF-PF (TS-EnKF-PF), which exchanges point estimates between EnKF and PF while requiring almost double the computational load. Numerical experiments are conducted with the Lorenz-96 model to assess the behavior of the proposed filter and to evaluate its performances against the joint PF, joint EnKF, and TS-EnKF-PF. Numerical results suggest that the EnKF-PF performs best in all tested scenarios. It was further found to be more robust, successfully estimating both state and parameters in different sensitivity experiments.

  2. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-01

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  3. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-07

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  4. Effects of filter housing and ductwork configuration on air flow uniformity inside air cleaning filter housings

    International Nuclear Information System (INIS)

    Paul, J.D.

    1993-01-01

    Each new HEPA filter installation presents a different physical configuration based on the system requirements, the available space and designer preference. Each different configuration can result in variations of air flow uniformity inside the filter housing across the filter banks. This paper presents the results of air flow uniformity testing for six different filter housing/ductwork configurations and discusses if any of those variations in air flow uniformity is attributable to the difference in the physical arrangements for the six cases

  5. Spectral-based features ranking for gamelan instruments identification using filter techniques

    Directory of Open Access Journals (Sweden)

    Diah P Wulandari

    2013-03-01

    Full Text Available In this paper, we describe an approach of spectral-based features ranking for Javanese gamelaninstruments identification using filter techniques. The model extracted spectral-based features set of thesignal using Short Time Fourier Transform (STFT. The rank of the features was determined using the fivealgorithms; namely ReliefF, Chi-Squared, Information Gain, Gain Ratio, and Symmetric Uncertainty. Then,we tested the ranked features by cross validation using Support Vector Machine (SVM. The experimentshowed that Gain Ratio algorithm gave the best result, it yielded accuracy of 98.93%.

  6. Modification of double vector control algorithm to filter out grid harmonics

    DEFF Research Database (Denmark)

    Awad, Hilmy; Blaabjerg, Frede

    2005-01-01

    terminals in the case of distorted grid voltage. Furthermore, a selective harmonic compensation strategy is applied to filter out the grid harmonics. The operation of the SSC under distorted utility conditions and voltage dips is discussed. The validity of the proposed controller is verified by experiments......, which have been carried out on a 10-kV SSC laboratory setup. Experimental results have shown the ability of the SSC to mitigate voltage dips and harmonics. It is also shown that the proposed controller has improved the transient performance of the SSC even under distorted utility conditions....

  7. Apparatus for filtering radioactive fluids

    International Nuclear Information System (INIS)

    Gischel, E.H.

    1975-01-01

    Apparatus is provided for filtering radioactive particles from the cooling and/or auxiliary process water of a nuclear reactor, or nuclear fuel processing plant, or other installations wherein radioactive fluid systems are known to exist. The apparatus affords disposal of the captured particles in a manner which minimizes the exposure of operating personnel to radioactivity. The apparatus comprises a housing adapted to contain a removable filter cartridge assembly, a valve normally closing the lower end of the housing, an upwardly-open shipping cask located below the valve, and an elongated operating rod assembly projecting upwardly from the filter cartridge assembly and through the upper end of the housing to enable a workman to dismount the filter cartridge assembly from its housing and to lower the filter cartridge assembly through the valve and into the cask from a remote location above the housing. (U.S.)

  8. Predicting inferior vena cava (IVC) filter retrievability using positional parameters: A comparative study of various filter types.

    Science.gov (United States)

    Gotra, A; Doucet, C; Delli Fraine, P; Bessissow, A; Dey, C; Gallix, B; Boucher, L-M; Valenti, D

    2018-05-14

    To compare changes in inferior vena cava (IVC) filter positional parameters from insertion to removal and examine how they affect retrievability amongst various filter types. A total of 447 patients (260 men, 187 women) with a mean age of 55 years (range: 13-91 years) who underwent IVC filter retrieval between 2007-2014 were retrospectively included. Post-insertion and pre-retrieval angiographic studies were assessed for filter tilt, migration, strut wall penetration and retrieval outcomes. ANCOVA and multiple logistic regression models were used to analyze factors affecting retrieval success. Pairwise comparisons between filter types were performed. Of 488 IVC filter retrieval attempts, 94.1% were ultimately successful. The ALN filter had the highest mean absolute value of tilt (5.6 degrees), the Optease filter demonstrated the largest mean migration (-8.0mm) and the Bard G2 filter showed highest mean penetration (5.2mm). Dwell time of 0-90 days (OR, 11.1; P=0.01) or 90-180 days (OR, 2.6; P=0.02), net tilt of 10-15 degrees (OR 8.9; P=0.05), caudal migration of -10 to 0mm (OR, 3.46; P=0.03) and penetration less than 3mm (OR, 2.6; P=0.01) were positive predictors of successful retrievability. Higher odds of successful retrieval were obtained for the Bard G2X, Bard G2 and Cook Celect when compared to the ALN and Cordis Optease filters. Shorter dwell time, lower mean tilt, caudal migration and less caval wall penetration are positive predictors of successful IVC filter retrieval. Copyright © 2018 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  9. Filter forensics: microbiota recovery from residential HVAC filters.

    Science.gov (United States)

    Maestre, Juan P; Jennings, Wiley; Wylie, Dennis; Horner, Sharon D; Siegel, Jeffrey; Kinney, Kerry A

    2018-01-30

    Establishing reliable methods for assessing the microbiome within the built environment is critical for understanding the impact of biological exposures on human health. High-throughput DNA sequencing of dust samples provides valuable insights into the microbiome present in human-occupied spaces. However, the effect that different sampling methods have on the microbial community recovered from dust samples is not well understood across sample types. Heating, ventilation, and air conditioning (HVAC) filters hold promise as long-term, spatially integrated, high volume samplers to characterize the airborne microbiome in homes and other climate-controlled spaces. In this study, the effect that dust recovery method (i.e., cut and elution, swabbing, or vacuuming) has on the microbial community structure, membership, and repeatability inferred by Illumina sequencing was evaluated. The results indicate that vacuum samples captured higher quantities of total, bacterial, and fungal DNA than swab or cut samples. Repeated swab and vacuum samples collected from the same filter were less variable than cut samples with respect to both quantitative DNA recovery and bacterial community structure. Vacuum samples captured substantially greater bacterial diversity than the other methods, whereas fungal diversity was similar across all three methods. Vacuum and swab samples of HVAC filter dust were repeatable and generally superior to cut samples. Nevertheless, the contribution of environmental and human sources to the bacterial and fungal communities recovered via each sampling method was generally consistent across the methods investigated. Dust recovery methodologies have been shown to affect the recovery, repeatability, structure, and membership of microbial communities recovered from dust samples in the built environment. The results of this study are directly applicable to indoor microbiota studies utilizing the filter forensics approach. More broadly, this study provides a

  10. Faraday anomalous dispersion optical filters

    Science.gov (United States)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  11. Performance comparison of various time variant filters

    Energy Technology Data Exchange (ETDEWEB)

    Kuwata, M [JEOL Engineering Co. Ltd., Akishima, Tokyo (Japan); Husimi, K

    1996-07-01

    This paper describes the advantage of the trapezoidal filter used in semiconductor detector system comparing with the other time variant filters. The trapezoidal filter is the compose of a rectangular pre-filter and a gated integrator. We indicate that the best performance is obtained by the differential-integral summing type rectangular pre-filter. This filter is not only superior in performance, but also has the useful feature that the rising edge of the output waveform is linear. We introduce an example of this feature used in a high-energy experiment. (author)

  12. Development of the code for filter calculation

    International Nuclear Information System (INIS)

    Gritzay, O.O.; Vakulenko, M.M.

    2012-01-01

    This paper describes a calculation method, which commonly used in the Neutron Physics Department to develop a new neutron filter or to improve the existing neutron filter. This calculation is the first step of the traditional filter development procedure. It allows easy selection of the qualitative and quantitative contents of a composite filter in order to receive the filtered neutron beam with given parameters

  13. A Game Theoretic Fault Detection Filter

    Science.gov (United States)

    Chung, Walter H.; Speyer, Jason L.

    1995-01-01

    The fault detection process is modelled as a disturbance attenuation problem. The solution to this problem is found via differential game theory, leading to an H(sub infinity) filter which bounds the transmission of all exogenous signals save the fault to be detected. For a general class of linear systems which includes some time-varying systems, it is shown that this transmission bound can be taken to zero by simultaneously bringing the sensor noise weighting to zero. Thus, in the limit, a complete transmission block can he achieved, making the game filter into a fault detection filter. When we specialize this result to time-invariant system, it is found that the detection filter attained in the limit is identical to the well known Beard-Jones Fault Detection Filter. That is, all fault inputs other than the one to be detected (the "nuisance faults") are restricted to an invariant subspace which is unobservable to a projection on the output. For time-invariant systems, it is also shown that in the limit, the order of the state-space and the game filter can be reduced by factoring out the invariant subspace. The result is a lower dimensional filter which can observe only the fault to be detected. A reduced-order filter can also he generated for time-varying systems, though the computational overhead may be intensive. An example given at the end of the paper demonstrates the effectiveness of the filter as a tool for fault detection and identification.

  14. HEPA Filter Performance under Adverse Conditions

    International Nuclear Information System (INIS)

    Parsons, Michael; Hogancamp, Kristina; Alderman, Steven; Waggoner, Charles

    2007-01-01

    This study involved challenging nuclear grade high-efficiency particulate air (HEPA) filters under a variety of conditions that can arise in Department of Energy (DOE) applications such as: low or high RH, controlled and uncontrolled challenge, and filters with physically damaged media or seals (i.e., leaks). Reported findings correlate filter function as measured by traditional differential pressure techniques in comparison with simultaneous instrumental determination of up and down stream PM concentrations. Additionally, emission rates and failure signatures will be discussed for filters that have either failed or exceeded their usable lifetime. Significant findings from this effort include the use of thermocouples up and down stream of the filter housing to detect the presence of moisture. Also demonstrated in the moisture challenge series of tests is the effect of repeated wetting of the filter. This produces a phenomenon referred to as transient failure before the tensile strength of the media weakens to the point of physical failure. An evaluation of the effect of particle size distribution of the challenge aerosol on loading capacity of filters is also included. Results for soot and two size distributions of KCl are reported. Loading capacities for filters ranged from approximately 70 g of soot to nearly 900 g for the larger particle size distribution of KCl. (authors)

  15. Comparison of cryogenic low-pass filters

    Science.gov (United States)

    Thalmann, M.; Pernau, H.-F.; Strunk, C.; Scheer, E.; Pietsch, T.

    2017-11-01

    Low-temperature electronic transport measurements with high energy resolution require both effective low-pass filtering of high-frequency input noise and an optimized thermalization of the electronic system of the experiment. In recent years, elaborate filter designs have been developed for cryogenic low-level measurements, driven by the growing interest in fundamental quantum-physical phenomena at energy scales corresponding to temperatures in the few millikelvin regime. However, a single filter concept is often insufficient to thermalize the electronic system to the cryogenic bath and eliminate spurious high frequency noise. Moreover, the available concepts often provide inadequate filtering to operate at temperatures below 10 mK, which are routinely available now in dilution cryogenic systems. Herein we provide a comprehensive analysis of commonly used filter types, introduce a novel compact filter type based on ferrite compounds optimized for the frequency range above 20 GHz, and develop an improved filtering scheme providing adaptable broad-band low-pass characteristic for cryogenic low-level and quantum measurement applications at temperatures down to few millikelvin.

  16. Comparison of cryogenic low-pass filters.

    Science.gov (United States)

    Thalmann, M; Pernau, H-F; Strunk, C; Scheer, E; Pietsch, T

    2017-11-01

    Low-temperature electronic transport measurements with high energy resolution require both effective low-pass filtering of high-frequency input noise and an optimized thermalization of the electronic system of the experiment. In recent years, elaborate filter designs have been developed for cryogenic low-level measurements, driven by the growing interest in fundamental quantum-physical phenomena at energy scales corresponding to temperatures in the few millikelvin regime. However, a single filter concept is often insufficient to thermalize the electronic system to the cryogenic bath and eliminate spurious high frequency noise. Moreover, the available concepts often provide inadequate filtering to operate at temperatures below 10 mK, which are routinely available now in dilution cryogenic systems. Herein we provide a comprehensive analysis of commonly used filter types, introduce a novel compact filter type based on ferrite compounds optimized for the frequency range above 20 GHz, and develop an improved filtering scheme providing adaptable broad-band low-pass characteristic for cryogenic low-level and quantum measurement applications at temperatures down to few millikelvin.

  17. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon

    2016-01-08

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  18. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon; Chernov, Alexey; Law, Kody; Nobile, Fabio; Tempone, Raul

    2016-01-01

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  19. FLOWING BILATERAL FILTER: DEFINITION AND IMPLEMENTATIONS

    Directory of Open Access Journals (Sweden)

    Maxime Moreaud

    2015-06-01

    Full Text Available The bilateral filter plays a key role in image processing applications due to its intuitive parameterization and its high quality filter result, smoothing homogeneous regions while preserving the edges of the objects. Considering the image as a topological relief, seeing pixel intensities as peaks and valleys, we introduce a way to control the tonal weighting coefficients, the flowing bilateral filter, reducing "halo" artifacts typically produced by the regular bilateral filter around a large peak surrounded by two valleys of lower values. In this paper we propose to investigate exact and approximated versions of CPU and parallel GPU (Graphical Processing Unit based implementations of the regular and flowing bilateral filter using the NVidia CUDA API. Fast implementations of these filters are important for the processing of large 3D volumes up to several GB acquired by x-ray or electron tomography.

  20. Iodine and creatinine testing in urine dried on filter paper

    Energy Technology Data Exchange (ETDEWEB)

    Zava, Theodore T., E-mail: ttzava@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States); Kapur, Sonia, E-mail: soniak@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States); Zava, David T., E-mail: dzava@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States)

    2013-02-18

    Highlights: ► Dried urine iodine and creatinine extract quantitatively correlates well with liquid urine. ► Filter paper strips can be easily shipped and stored. ► Urine iodine and creatinine are stable at ambient temperature when dried on filter paper. ► Dried urine iodine and creatinine are run using a 96-well format. -- Abstract: Iodine deficiency is a world-wide health problem. A simple, convenient, and inexpensive method to monitor urine iodine levels would have enormous benefit in determining an individual's recent iodine intake or in identifying populations at risk for iodine deficiency or excess. Current methods used to monitor iodine levels require collection of a large volume of urine and its transport to a testing laboratory, both of which are inconvenient and impractical in parts of the world lacking refrigerated storage and transportation. To circumvent these limitations we developed and validated methods to collect and measure iodine and creatinine in urine dried on filter paper strips. We tested liquid urine and liquid-extracted dried urine for iodine and creatinine in a 96-well format using Sandell–Kolthoff and Jaffe reactions, respectively. Our modified dried urine iodine and creatinine assays correlated well with established liquid urine methods (iodine: R{sup 2} = 0.9483; creatinine: R{sup 2} = 0.9782). Results demonstrate that the dried urine iodine and creatinine assays are ideal for testing the iodine status of individuals and for wide scale application in iodine screening programs.