58 research outputs found
Centralized Inverted Decoupling Control
This paper presents a new methodology of multivariable centralized control based on the structure of inverted decoupling. The method is presented for general nĂn processes, obtaining very simple general expressions for the controller elements with a complexity independent of the system size. The possible configurations and realizability conditions are stated. Then, the specification of performance requirements is carried out from simple open loop transfer functions for three common cases. As a particular case, it is shown that the resulting controller elements have PI structure or filtered derivative action plus a time delay when the process elements are given by first order plus time delay systems. Comparisons with other works demonstrate the effectiveness of this methodology through the use of several simulation examples and an experimental lab process
HbA1c levels in schoolchildren with type 1 diabetes are seasonally variable and dependent on weather conditions
Aims/hypothesis: We evaluated seasonal HbA changes in children with type 1 diabetes and its relation with measures of weather conditions. Methods: HbA changes over more than 3 years were evaluated in type 1 diabetic patients who were younger than 18 years and had diabetes duration of more than 12 months, and correlated with measures of weather conditions (ambient temperature, hours of sunshine and solar irradiance). After comparison of autocorrelation patterns, patterns of metabolic control and meteorological data were evaluated using Spearman rank correlation. Results: A total of 3,935 HbA measurements in 589 school (â„7 years) and 88 preschool (<7 years) children were analysed. Mean (±SD) HbA level for the whole study period was 7.65±1.12%. The lowest HbA levels were observed in late summer and the highest in winter months, with differences consistently exceeding 0.44%. Autocorrelation analysis of HbA levels in schoolchildren showed a sine-wave pattern with a cycle length of roughly 12 months, which mirrored changes in ambient temperature. Strong negative correlations of HbA with ambient temperature (R=â0.56; p=0.0002), hours of sunshine (R=â0.52; p=0.0007) and solar irradiance (R=â0.52; p=0.0006) were present in schoolchildren, but not in preschoolers (pâ„0.29 for each correlation). Conclusions/interpretation: Seasonal changes of HbA levels in schoolchildren with type 1 diabetes are a significant phenomenon and should be considered in patient education and diabetes management. They may potentially affect the results of clinical trials using HbA levels as their primary outcome, as well as HbA-based diagnosis of diabetes
Taking stock of 10 years of published research on the ASHA programme: Examining Indiaâs national community health worker programme from a health systems perspective
Background: As Indiaâs accredited social health activist (ASHA) community health worker (CHW) programme enters its second decade, we take stock of the research undertaken and whether it examines the health systems interfaces required to sustain the programme at scale.
Methods: We systematically searched three databases for articles on ASHAs published between 2005 and 2016. Articles that met the inclusion criteria underwent analysis using an inductive CHWâhealth systems interface framework.
Results: A total of 122 academic articles were identified (56 quantitative, 29 mixed methods, 28 qualitative, and 9 commentary or synthesis); 44 articles reported on special interventions and 78 on the routine ASHA program. Findings on special interventions were overwhelmingly positive, with few negative or mixed results. In contrast, 55% of articles on the routine ASHA programme showed mixed findings and 23% negative, with few indicating overall positive findings, reflecting broader system constraints. Over half the articles had a health system perspective, including almost all those on general ASHA work, but only a third of those with a health condition focus. The most extensively researched health systems topics were ASHA performance, training and capacity-building, with very little research done on programme financing and reporting, ASHA grievance redressal or peer communication. Research tended to be descriptive, with fewer influence, explanatory or exploratory articles, and no predictive or emancipatory studies. Indian institutions and authors led and partnered on most of the research, wrote all the critical commentaries, and published more studies with negative results.
Conclusion: Published work on ASHAs highlights a range of small-scale innovations, but also showcases the challenges faced by a programme at massive scale, situated in the broader health system. As the programme continues to evolve, critical comparative research that constructively feeds back into programme reforms is needed, particularly related to governance, intersectoral linkages, ASHA solidarity, and community capacity to provide support and oversight
StatickĂœ kompenzĂĄtor pro decentralizovanĂ© ĆĂzenĂ neÄtvercovĂœch soustav
The paper deals with the decentralized control problem for linear multivariable systems with the number of manipulated variables equal or greater than the number of controlled variables. Proposed static compensator ensures automatic creation of input/output pairs for individual control loops. The compensator provides steady state autonomy and unit gain for the control loops. Steady state gain matrix of the controlled system and vector of offsets are sufficient infor-mation for the compensator design. Estimation of the gain matrix and offsets from the measured data is also proposed in the paper.ÄlĂĄnek je vÄnovĂĄn decentralizovanĂ©mu ĆĂzenĂ vĂcerozmÄrnĂœch systĂ©mĆŻ s poÄtem regulovanĂœch veliÄin rovnĂœm nebo vÄtĆĄĂm neĆŸ je poÄet akÄnĂch veliÄin. NavrĆŸenĂœ statickĂœ kompenzĂĄtor vytvoĆĂ pĂĄry vstup/vĂœstup pro jednoduchĂ© regulaÄnĂ obvody, zajistĂ autonomnost v ustĂĄlenĂ©m stavu a jednotkovĂ© zesĂlenĂ. Matice zesĂlenĂ soustavy a vektor ofsetĆŻ je dostateÄnĂĄ informace pro nĂĄvrh kompenzĂĄtoru. V ÄlĂĄnku je takĂ© navrĆŸen postup pro odhad matice zesĂlenĂ a ofsetĆŻ soustavy
StatickĂœ kompenzĂĄtor pro neÄtvercovĂ© soustavy - aplikaÄnĂ pĆĂklad
The paper deals with the decentralized control of multivariable systems with the number of manipulated variables greater than the number of controlled variables. Proposed static compensator ensures automatic creation of input/output pairs for the simple control loops. The compensator provides steady-state autonomy and unit gain of the controlled system. Steady-state gain matrix and vector of the off-sets are enough information for the compensator design. Laboratory example is presented to demonstrate innovative compensator design and its application.ÄlĂĄnek se zabĂœvĂĄ ĆĂzenĂm soustav s vÄtĆĄĂm poÄtem akÄnĂch veliÄin, neĆŸ je poÄet regulovanĂœch veliÄin. Je navrĆŸen statickĂœ kompenzĂĄtor, tak aby mohly bĂœt vytvoĆeny jednotlivĂ© regulaÄnĂ smyÄky
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