LPV-based quality interpretations on modeling and control of diabetes

In this study we introduce different novel interpretations in the case of Linear Parameter Varying (LPV) methodology, which are directly usable in modeling and control design in diabetes research. These novel interpretations are based on the parameter vectors of the LPV parameter space. The theoretical solutions are demonstrated on a simple, known Type 1 Diabetes Model used in intensive care

A versengés jutalmazásának hatása a nyáltesztoszteronszintre és a teljesítményre fiatal felnőtt férfiakban: A hiperversengés szerepe

Korábbi kutatások megmutatták, hogy versengő helyzetben a nagyobb jutalom megnövekedett fiziológiai arousallal jár. Mégis kevés tanulmány érintette a jutalmazás hatását a tesztoszteron (T) szintre, annak ellenére, hogy ez a hormon érzékenyen reagál a versengő helyzetekre és státuszváltozásokra. A jelen kutatás versengő helyzetben vizsgálta a nyáltesztoszteron és fiziológiai arousal (szívritmus, szívritmusvariabilitás) változásait fiatal felnőtt férfi mintán (N = 40, átlag életkor = 21.7 ± 2.3 év). A résztvev ők egy videojátékban versengtek egymással, ahol a páros egyik tagja nyert, a másik veszített a képességeknek és erőfeszítésnek megfelelően. A párosok véletlenszerű csoportosítása alapján résztvevők vagy egyenlő pénzjutalmat kaptak, vagy a győztes több jutalmat kapott, mint a vesztes (egyenlőtlen jutalom). A pszichofiziológiai és endokrinológiai méréseken túl a résztvevők versengéssel kapcsolatos attitűdjeit (hiperversengés, önfejlesztő versengés) és a versengő helyzetben mutatott hangulati változásait is felmértük kérdőívek segítségével. Az eredmények azt mutatták, hogy a versengés mindkét csoportban növelte mind a szubjektív, mind a fiziológiai arousalszintjét, ám a jutalom mértéke nem volt szignifikáns hatással a T szintre. A T szint csak a vesztes hiperversengőkben növekedett szignifikánsan. A kompetitív teljesítmény korrelált a győztesek és vesztesek T szintjével, illetve annak változásával, alátámasztva azt a korábbi megfigyelést, hogy a versengő teljesítmény és a T egymást kölcsönösen meghatározó kapcsolatban állnak. A kapott eredmények összefüggésben vannak a státuszinstabilitás-hipotézissel

Investigation of the TP-based modeling possibility of a nonlinear ICU diabetes model

In-silico modeling is an important part of biomedical engineering. Advanced controllers providing high quality control can be validated through it checking if the available mathematical model of the given biomedical process produces the desired output. However, due to high patient variability the advanced linear control methods applied on linearized models could produce several distortions compared to the original nonlinear models; hence, these errors should be reduced. Hierarchical control strategies could be a possibility or from modeling point of view using different control-oriented modeling methodologies. Linear Parameter Varying (LPV) approaches with Linear Matrix Inequality (LMI) based modeling and controller design represent one choice. In this paper, we investigate their generalized extension, the Tensor Product (TP) model transformation demonstrated on diabetes modeling. In concrete, the type 1 diabetes modeling on Intensive Care Units (ICU) is envisaged. The achieved results will be used for TP transformation based controller design in our later wor

Late Pleistocene millennial scale cycles of aeolian sedimentation in the Dunaszekcső loess record, south Hungary: preliminary data and interpretations

Millennial scale warm-cold oscillations in air temperature over Greenland and rapid sea surface temperature changes were recorded in ice cores and North Atlantic sediments for the last glaciation. These events must have been associated with profound environmental changes in Europe, and indeed, millennial scale oscillations in grain size records have been found in loess deposits of Europe and Asia. Unfortunately, the timing of these events are still unresolved due to chronological uncertainties on the order of thousands of years. Major problems are the low precision of luminescence ages and the general lack of materials that can reliably be dated using 14C. As demonstrated by 24 OSL/IRSL ages, the Dunaszekcső loess-palaeosol sequence is an archive of climate and environmental changes of the last glacial-interglacial cycles. For the upper part of the section (<33 cal yr BP), the chronology is further refined based on charcoal and mollusc shell radiocarbon ages. Here we show that AMS 14C ages of some mollusc species having small shells (<10 mm) seem to yield reliable ages in a comparison with charcoal 14C ages. These radiocarbon ages are consistent, have low variability and define age-depth models with sufficient precision to examine the timing of paleoenvironmental changes in the context of North Atlantic climatic variations. Bayesian age-depth modeling was performed using Bacon for a depth of 865-500 cm and a time span of 33-25 kyr based on 16 radiocarbon ages. Mean confidence ranges are 674 yr with a minimum of 416 yr at 630 cm and a maximum of 917 yr at 865 cm. Such a sub-millennial scale age model precision has formerly been unprecedented for loess profiles. Sedimentation rates calculated from the Bayesian age-depth model vary between 0.3 and 1.1 mm year‒1 (=m kyr‒1) with the maximum at 27.390±230 cal yr BP. Estimated bulk dust flux for the studied site and the given time span range from 493 to 1666 g m‒2 yr‒1, calculating with a dry density of loess of 1500 kg m‒3. Both the sedimentation rate and dust flux show millennial scale variations, together with the median grain size (Md) of bulk loess that is considered an integrated proxy of wind strength, dust source distance and source aridity. The Md proxy reveal sub-millennial scale variations, too, but the interpretation of such oscillations are far from straightforward. Nevertheless, the millennial scale variations in the Aeolian sedimentation imply strong and rapid changes in the frequency (and magnitude?) of dust storm events for the period of 33-25 kyr. Further preliminary observations are that grain size (Md) maxima lag behind the NGRIP dust peaks (Ca2+) by ca. 300-500 years and grain size minima closely follows Ca2+ and δ18O minima (GI-4 and 3). It must be noted, however, that the 300-500 years lags are within age model uncertainties

Effect of Model, Observer and Their Interaction on State and Disturbance Estimation in Artificial Pancreas: An In-Silico Study

The state and disturbance estimations are an indispensable part of the state-of-the-art model-based controllers as related to the artificial pancreas, supporting the decision-making and self-tuning of the algorithms. They are not just important when state-feedback kind of controller structure is applied, but also play a crucial role in the estimation of, for example, the amount of the acting drug (insulin) in blood or meal intake estimation which has determining role in the short and long term effectivity of the given therapy. This information is also important for physicians to support them in knowledge-based decision-making to be sure a given therapy or device works well. This article compares three observers &#x2013; a linear-parameter-varying (LPV) dual Kalman filter (KF), a LPV joint KF, and a nonlinear sliding mode observer (NSMO) &#x2013; designed with two individualized models &#x2013; Hovorka and Identifiable Virtual Patient model (IVP). The article also statistically quantifies the effect of the observer algorithm and model structure on the accuracy of the estimation of plasma insulin, rate of glucose appearance, and glucose. Data for the analysis was generated by the UVa-Padova simulator. Results indicated that, for the rate of glucose appearance and the plasma insulin, the type of model and the observer structure explain less than 10&#x0025; of the variability in the error, while the inter-patient variability contributes to the error more than 50&#x0025;. This reveals a limiting factor in the estimation accuracy that might be improved by model parameter adaptation

Spin-dependent transport in nanocomposite C:Co films

The magneto-transport properties of nanocomposite C:Co (15 and 40 at.% Co) thin films are investigated. The films were grown by ion beam co-sputtering on thermally oxidized silicon substrates in the temperature range from 200 to 500 degC. Two major effects are reported: (i) a large anomalous Hall effect amounting to 2 \mu ohm cm, and (ii) a negative magnetoresistance. Both the field-dependent resistivity and Hall resistivity curves coincide with the rescaled magnetization curves, a finding that is consistent with spin-dependent transport. These findings suggest that C:Co nanocomposites are promising candidates for carbon-based Hall sensors and spintronic devices.Comment: 13 pages, 7 figure