Home About us Contact
|
Home About us Contact | ||
|
|
||
Actual System (actual + system)
Selected AbstractsModelling for an expert system and a parameter validation methodEXPERT SYSTEMS, Issue 5 2002A. Chatzinikolaou A model,based engineering diagnostic method is typically based on the evaluation of the residuals generated from a comparison of important variable values from a simulated system and the corresponding measured values from the system's performance. Consequently, a model should describe the dynamic behaviour of the system as accurately as possible using suitably selected parameter values. This implies the need for validation of the performance of the model by comparison with the measurements of the actual system. This process is especially important when the detection of faults is performed in real,time conditions. In this paper, the modelling process for hydraulic systems as well as a new parameter validation method that has been developed using the DASYLab data acquisition and control software for the estimation of the uncertain parameter values of the model is presented. This model validation process led to the establishment of a model,based expert system that is able to diagnose real,time faults working in parallel with actual dynamic industrial automated processes. [source] Strong robustness in multi-phase adaptive control: the basic schemeINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2004Maria Cadic Abstract The general structure of adaptive control systems based on strong robustness is introduced. This approach splits into two phases. In the first phase, emphasis is put on identification until enough information is obtained in order to design a controller that stabilizes the actual system, and even under adaptation. This is achieved if the input sequence is computed in such a way that the uncertainty on the parameters of the system to be controlled becomes sufficiently small. Then, in the second phase, effort is shifted to control via a traditional certainty equivalence type of strategy. Copyright © 2004 John Wiley & Sons, Ltd. [source] Charge parameterization of the metal centers in cytochrome c oxidaseJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 5 2008Mikael P. Johansson Abstract Reliable atomic point charges are of key importance for a correct description of the electrostatic interactions when performing classical, force field based simulations. Here, we present a systematic procedure for point charge derivation, based on quantum mechanical methodology suited for the systems at hand. A notable difference to previous procedures is to include an outer region around the actual system of interest. At the cost of increasing the system sizes, here up to 265 atoms, including the surroundings achieves near-neutrality for the systems as well as structural stability, important factors for reliable charge distributions. In addition, the common problem of converting between CH bonds and CC bonds at the border vanishes. We apply the procedure to the four redox-active metal centers of cytochrome c oxidase: CuA, haem a, haem a3, and CuB. Several relevant charge and ligand states are considered. Charges for two different force fields, CHARMM and AMBER, are presented. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] Waiting list management: priority criteria or first-in first-out?JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 4 2009A case for total joint replacement Abstract Background, Total joint replacements are interventions with large waiting times from indication to the surgery management. These patients can be managed in two ways; first-in first-out or through a priority tool. The aim of this study was to compare real time on waiting list (TWL) with a priority criteria score, developed by our team, in patients awaiting joint replacement due to osteoarthritis. Methods, Consecutive patients placed on waiting list were eligible. Patients fulfilled a questionnaire which included items of our priority tool and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) specific questionnaire. Other priority items were extracted from the clinical history. The priority tool gives a score from 0 to 100 points, and three categories (urgent, preferent and ordinary). We studied the differences among categories and TWL by means of one-way analysis of variance. Correlational analysis was used to evaluate association among priority score and TWL and WOMAC baseline and gains at 6 months with priority score and TWL. Results, We have studied 684 patients. Women represented 62% of sample. The mean age was 70 years. There were not association between the categories of priority score and TWL (P = 0.12). The rho correlation coefficient between TWL and priority score was ,0.11. Among baseline WOMAC scores and priority score, the rho coefficients were 0.79, 0.7 and 0.52 with function, pain and stiffness dimensions, respectively. There were differences in the mean scores of WOMAC dimensions according to the three priority categories (P < 0.001) but no with TWL categories. Data of gains in both health-related quality of life dimensions at 6 months were similar, with differences according to priority categories but no regarding TWL. Conclusions, The results of the study support the necessity of implementing a prioritization system instead of the actual system if we want to manage the waiting list for joint replacement with clinical equity. [source] VISCOELASTICITY OF A SIMULATED POLYMER AND COMPARISON WITH CHICKPEA FLOUR DOUGHSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2006NIDHI YADAV ABSTRACT An integrated approach consisting of compression and stress relaxation is performed with a simulated model system of poly dimethyl siloxane (PDMS), a viscoelastic polymer material when the compressive strain, height of sample and crosshead speed were varied. The parameters derived are the forces at the end of compression and relaxation, energy for compression and the extent of elasticity of the sample based on the ratios of forces as well as the proposed energy values. The results were verified with food doughs undergoing large deformations that show a nonlinear behavior. The proposed extent of elasticity based on the ratios of energy stored and compression can be used as an index for the characterization of viscoelasticity. A nonlinear three-parameter model had also been proposed to predict the stress decay characteristics as a function of time, which was found suitable for the PDMS system, and was better than the two-parameter Peleg model as judged by lower variance values (0.0006,0.018 and 0.002,0.048, respectively). Further, an actual system of food doughs in the form of chickpea (Cicer arietinum L.) flour dough was used to verify the proposed model and viscoelastic index at different moisture contents (27,39%) subjected to compressive strains of 25,75%. The nonlinear relaxation characteristics of the food dough are sensitive to moisture content as well as to strain level. [source] Unique Characteristics of Emergency Care Research: Scope, Populations, and InfrastructureACADEMIC EMERGENCY MEDICINE, Issue 10 2009D. Mark Courtney MD Abstract The National Institutes of Health (NIH) Clinical and Translational Science Awards (CTSA) program and the 2006 Institute of Medicine (IOM) Report on the future of emergency care highlight the need for coordinated emergency care research (ECR) to improve the outcomes of acutely ill or injured patients. In response, the Society for Academic Emergency Medicine (SAEM) and the American College of Emergency Physicians (ACEP) sponsored the Emergency Care Research Network (ECRN) Conference in Washington, DC, on May 28, 2008. The conference objectives were to identify the unique nature of ECR and the infrastructure needed to support ECR networks and to understand the optimal role of emergency medicine (EM) and other acute care specialties in research networks. Prior to the conference, participants responded to questions addressing the relevant issues that would form the basis of breakout session discussions; two of these breakout questions are summarized in this report: 1) what makes EM research unique? and 2) what are the critical components needed to establish and maintain networked ECR? Emergency care research was defined as "the systematic examination of patient care that is expected to be continuously available to diverse populations presenting with undifferentiated symptoms of acute illness, or acutely decompensated chronic illness, and whose outcomes depend on timely diagnosis and treatment." The chain of ECR may extend beyond the physical emergency department (ED) in both place and time and integrate prehospital care, as well as short- and long-term outcome determination. ECR may extend beyond individual patients and have as the focus of investigation the actual system of emergency care delivery itself and its effects on the community with respect to access to care, use of resources, and cost. Infrastructure determinants of research network success identified by conference participants included multidisciplinary collaboration, accurate long-term outcome determination, novel information technology, intellectual infrastructure, and wider network relationships that extend beyond the ED. [source] FAULT DETECTION, ISOLATION AND RECONSTRUCTION FOR DESCRIPTOR SYSTEMSASIAN JOURNAL OF CONTROL, Issue 4 2005Tae-Kyeong Yeu ABSTRACT In this paper, we consider fault detection, isolation and reconstruction problem for descriptor systems with actuator faults and sensor faults, respectively. When actuator faults exist in the system, the fault detection and isolation (FDI) problem is solved through an unknown input observer regarding remaining faults excluded a specified fault as unknown inputs. Whereas, in existing sensor faults, the fault detection is only achieved by the unknown input observer and residual signals. Since the derivative signal of sensor fault is generated in the error dynamics between the actual system and the derived observer. The main objective of this work attempts the reconstruction of the faults. The reconstruction can be achieved by sliding mode observer including feedforward injection map and compensation signal. Finally, the isolation problem of sensor faults is solved by reconstructing all of the faults. [source] | ||||||||||||||||