The SIMC (Simple control) rule, proposed by Skogestad, is ineffective for a class of processes with oscillatory dynamics and processes defined by transfer functions obtained as a result of ideal ...decoupling of multiple-input multiple-output systems. For this class of stable processes it is proposed to apply a higher-order filtering to the open-loop process step response and to approximate the filtered step response with stable SOPDT models. These models are used to obtain a high performance/robustness tradeoff by the ideal series PID controllers, tuned by the SIMC rule, with the higher-order filter in the feedback loop. Parallel PID controllers, with higher-order noise filters, tuned by applying exact process frequency response and optimization under constraints on the robustness and sensitivity to measurement noise, are used to demonstrate merits of the proposed simple design and tuning of the series PID controller. Experimental results on a mechanical laboratory plant are presented in Appendix.
In the educational context, the term ‘workshop’ refers to a type of educational programme generally designed for a group of people, in which the content is practical, specific to the needs, interests ...and affinities of the group, and which enables cooperation and mutual support among participants. Workshops usually consist of a series of specifically tailored activities represented in the form of an intensive interactive educational programme or training, varying in length and content. Workshops can vary widely in their explicit and implicit goals, as well as strategies, methods and techniques employed. The orientation of workshop, the results it is designed to achieve, its objectives and positioning are key aspects in distinguishing different types of workshops and that will be the focus of this paper along with the basic knowledge teachers are required to have in order to organize workshops in the 21st century educational context.
This paper aims to reduce the amount of physical space the electrocardiogram data occupies and needs to be transferred, designing an efficient algorithm that can run on hardware commonly found in a ...medical device setting. The algorithm needs to be compatible with real-time data transfer and be fast and lossless. We introduce an algorithm inspired by pulse code modulation in telecommunication theory based on successive differences between neighboring electrocardiogram samples. The research hypothesis addressed in this paper finds if the new algorithm can reduce the data size by a meaningful amount and efficiently. Further on we tackle the research questions to find the level of distortion, compression, and processing speed of compression and decompression, along with the analysis of benefits and disadvantages. We reduced the storage space or bits to be transferred up to 46% reaching a compression ratio of 2.17 for an electrocardiogram benchmark dataset of up to 100 Mbits.
The increase in network connectivity has also resulted in several high-profile attacks on cyber-physical systems. An attacker that manages to access a local network could remotely affect control ...performance by tampering with sensor measurements delivered to the controller. Recent results have shown that with network-based attacks, such as Man-in-the-Middle attacks, the attacker can introduce an unbounded state estimation error if measurements from a suitable subset of sensors contain false data when delivered to the controller. While these attacks can be addressed with the standard cryptographic tools that ensure data integrity, their continuous use would introduce significant communication and computation overhead. Consequently, we study effects of intermittent data integrity guarantees on system performance under stealthy attacks. We consider linear estimators equipped with a general type of residual-based intrusion detectors (including χ2 and CUSUM detectors), and show that even when integrity of sensor measurements is enforced only intermittently, the attack impact is significantly limited; specifically, the state estimation error is bounded or the attacker cannot remain stealthy. Furthermore, we present methods to: (1) evaluate the effects of any given integrity enforcement policy in terms of reachable state-estimation errors for any type of stealthy attacks, and (2) design an enforcement policy that provides the desired estimation error guarantees under attack. Finally, on three automotive case studies we show that even with less than 10% of authenticated messages we can ensure satisfiable control performance in the presence of attacks.
EMG based biofeedback with the smarting system Jovanov, Ilija M.; Popovic, Dejan B.
12th Symposium on Neural Network Applications in Electrical Engineering (NEUREL),
2014-Nov.
Conference Proceeding
Learning of a skill is a practice (task related exercise) in which feedback provides information about the performance. If the feedback signal comes from physiological activity then it is termed ..."biofeedback". We present a new algorithm for real time classification of muscle activities from several muscles that can be used for feedback that is motivating for the student to learn. We used the "Smarting" system that is light (40 g), self-standing, has a 24-channels digital amplifier, and communicates via Bluetooth with an Android or Windows based platform/monitor. The Smarting system can record voltages above about 1 μV in the frequency range from 0 to 250 Hz (sampling rate at 500 Hz). The algorithm operates on the receiving platform in the Matlab environment. We present implementation of the algorithm for the recognition/distinction of four movements: fingers extension and flexion, and radial and ulnar flexion. The feedback that was used is a custom designed game on the computer (car race) where the car is controlled by four distinct signals recognized from muscle activities recorded with 18 points on the skin (monopolar configuration). The system can be implemented for other games which require four inputs since it operates as the computer peripheral. The system was designed for neurorehabilitation of humans after brain injury or disease but with the intention to be used for personal computer control, dedicated system control, and gaming.
The choroid plexus secretes cerebrospinal fluid and is critical for the development and function of the brain. In the telencephalon, the choroid plexus epithelium arises from the Wnt- expressing ...cortical hem. Canonical Wnt signaling pathway molecules such as nuclear β-CATENIN are expressed in the mouse and human embryonic choroid plexus epithelium indicating that this pathway is active. Point mutations in human β-CATENIN are known to result in the constitutive activation of canonical Wnt signaling. In a mouse model that recapitulates this perturbation, we report a loss of choroid plexus epithelial identity and an apparent transformation of this tissue to a neuronal identity. Aspects of this phenomenon are recapitulated in human embryonic stem cell derived organoids. The choroid plexus is also disrupted when β-Catenin is conditionally inactivated. Together, our results indicate that canonical Wnt signaling is required in a precise and regulated manner for normal choroid plexus development in the mammalian brain.
None of the proposed mechanisms of Alzheimer's disease (AD) fully explains the distribution patterns of the neuropathological changes at the cellular and regional levels, and their clinical ...correlates. One aspect of this problem lies in the complex genetic, epigenetic, and environmental landscape of AD: early-onset AD is often familial with autosomal dominant inheritance, while the vast majority of AD cases are late-onset, with the ε4 variant of the gene encoding apolipoprotein E (APOE) known to confer a 5-20 fold increased risk with partial penetrance. Mechanisms by which genetic variants and environmental factors influence the development of AD pathological changes, especially neurofibrillary degeneration, are not yet known. Here we review current knowledge of the involvement of the monoaminergic systems in AD. The changes in the serotonergic, noradrenergic, dopaminergic, histaminergic, and melatonergic systems in AD are briefly described. We also summarize the possibilities for monoamine-based treatment in AD. Besides neuropathologic AD criteria that include the noradrenergic locus coeruleus (LC), special emphasis is given to the serotonergic dorsal raphe nucleus (DRN). Both of these brainstem nuclei are among the first to be affected by tau protein abnormalities in the course of sporadic AD, causing behavioral and cognitive symptoms of variable severity. The possibility that most of the tangle-bearing neurons of the LC and DRN may release amyloid β as well as soluble monomeric or oligomeric tau protein trans-synaptically by their diffuse projections to the cerebral cortex emphasizes their selective vulnerability and warrants further investigations of the monoaminergic systems in AD.
Does Alzheimer's disease begin in the brainstem? Simic, G.; Stanic, G.; Mladinov, M. ...
Neuropathology & applied neurobiology/Neuropathology and applied neurobiology,
November 2009, Letnik:
35, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Although substantial evidence indicates that the progression of pathological changes of the neuronal cytoskeleton is crucial in determining the severity of dementia in Alzheimer's disease (AD), the ...exact causes and evolution of these changes, the initial site at which they begin, and the neuronal susceptibility levels for their development are poorly understood. The current clinical criteria for diagnosis of AD are focused mostly on cognitive deficits produced by dysfunction of hippocampal and high‐order neocortical areas, whereas noncognitive, behavioural and psychological symptoms of dementia such as disturbances in mood, emotion, appetite, and wake–sleep cycle, confusion, agitation and depression have been less considered. The early occurrence of these symptoms suggests brainstem involvement, and more specifically of the serotonergic nuclei. In spite of the fact that the Braak and Braak staging system and National Institutes of Aging – Reagan Institute (NIA‐RI) criteria do not include their evaluation, several recent reports drew attention to the possibility of selective and early involvement of raphe nuclei, particularly the dorsal raphe nucleus (DRN), in the pathogenesis of AD. Based on these findings of differential susceptibility and anatomical connectivity, a novel pathogenetic scheme of AD progression was proposed. Although the precise mechanisms of neurofibrillary degeneration still await elucidation, we speculated that cumulative oxidative damage may be the main cause of DRN alterations, as the age is the main risk factor for sporadic AD. Within such a framework, β‐amyloid production is considered only as one of the factors (although a significant one in familial cases) that promotes molecular series of events underlying AD‐related neuropathological changes.
Selective electrochemical reduction of CO2 is an emerging field which needs more active and stable catalysts for its practicability. In this work, we have studied the influence of Ag metal ...incorporation into Cu dendritic structures on the product distribution and selectivity of CO2 electroreduction. Bimetallic AgCu foams prepared by hydrogen bubble templated electrodeposition shift the potentials of CO production to more positive values compared to bulk silver. The presence of Ag during the electrodeposition significantly changed the size and the shape of the dendrites in the pore walls of AgCu foams compared to Cu foam. The CO adsorption characteristics are studied by operando Raman spectroscopy. In the presence of Ag, the maximum CO adsorption is observed at a more positive potential. As a result, an improved selectivity for CO is obtained for AgCu foam catalysts at lower overpotentials compared to Cu foam catalyst, evidencing a synergistic effect between the bimetallic components. We were successful in increasing the CO mass activity with respect to the total Ag amount. AgCu foams are found to retain the CO selectivity during long-term operation, and with their easily scalable electrodeposition synthesis they possess high potential for industrial application.
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