scholarly journals Diagnosis of Active Systems with Abstract Observations and Compiled Knowledge

2021 ◽  
Author(s):  
Gianfranco Lamperti ◽  
Marina Zanella ◽  
Xiangfu Zhao
Keyword(s):  
State Transition ◽  
Discrete Event ◽  
Abductive Reasoning ◽  
State Transitions ◽  
Active System ◽  
Active Systems ◽  
Communicating Automata ◽  
Speed Up ◽  
Single State ◽  
Extended Notion

An active system (AS) is a discrete-event system (DES) with asynchronous behavior, which is represented by a network of components that are modeled as communicating automata. When being operated, an AS performs a trajectory within its behavior space, while generating a sequence of observations, namely a temporal observation. The model of the AS and a temporal observation are the two key ingredients of the diagnosis task, which aims to find out possible faulty behavior via abductive reasoning. Among other knowledge, such reasoning requires knowing what is observable and what is not. This essential distinction constitutes the observability of the AS. In the literature, the observability of a DES boils down to qualifying each state transition either as observable or unobservable, which contrasts with the way humans observe reality, typically by mapping a collection of observations to a single, abstract perception. Moreover, the occurrence of single state transitions is not necessarily what we can observe or what we want to observe for diagnosis purposes. This paper presents an extended notion of observability, where each observation is associated with a behavioral scenario rather than a single state transition, where a scenario is defined as a regular language on state transitions. To speed up the online diagnosis engine, specific diagnosis-oriented knowledge is compiled offline. Eventually, the diagnosis technique based on abstract observability is extended to cope with temporal uncertainty.

scholarly journals Viscoelasticity and cell jamming state transition

2021 ◽  
Author(s):  
Ivana Pajic-Lijakovic ◽  
Milan Milivojevic
Keyword(s):  
Residual Stress ◽  
Wound Healing ◽  
Cell Migration ◽  
State Transition ◽  
State Transitions ◽  
Collective Cell Migration ◽  
Biological Processes ◽  
Cell Mobility ◽  
Controversial Topic ◽  
The Impact

Although collective cell migration (CCM) is a highly coordinated migratory mode, perturbations in the form of jamming state transitions and vice versa often occur even in 2D. These perturbations are involved in various biological processes, such as embryogenesis, wound healing and cancer invasion. CCM induces accumulation of cell residual stress which has a feedback impact to cell packing density. Density-mediated change of cell mobility influences the state of viscoelasticity of multicellular systems and on that base the jamming state transition. Although a good comprehension of how cells collectively migrate by following molecular rules has been generated, the impact of cellular rearrangements on cell viscoelasticity remains less understood. Thus, considering the density driven evolution of viscoelasticity caused by reduction of cell mobility could result in a powerful tool in order to address the contribution of cell jamming state transition in CCM and help to understand this important but still controversial topic. In addition, five viscoelastic states gained within three regimes: (1) convective regime, (2) conductive regime, and (3) damped-conductive regime was discussed based on the modeling consideration with special emphasis of jamming and unjamming states.

Zero-Energy Active Suspension System for Automobiles With Adaptive Sky-Hook Damping

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Kalpesh Singal ◽  
Rajesh Rajamani
Keyword(s):  
Active Suspension ◽  
Suspension System ◽  
Energy Management System ◽  
Zero Energy ◽  
Passive System ◽  
Active System ◽  
Active Suspensions ◽  
Resonant Frequencies ◽  
Active Systems ◽  
Automotive Suspension

Previous research has shown that a semiactive automotive suspension system can provide significant benefits compared to a passive suspension but cannot quite match the performance of a fully active system. The advantage of the semiactive system over an active system is that it consumes almost zero energy by utilizing a variable damper whose damping coefficient is changed in real time, while a fully active suspension consumes significant power for its operation. This paper explores a new zero-energy active suspension system that combines the advantages of semiactive and active suspensions by providing the performance of the active system at zero energy cost. Unlike a semiactive system in which the energy is always dissipated, the proposed system harvests and recycles energy to achieve active operation. An electrical motor-generator is used as the zero-energy actuator and a controller and energy management system are developed. An energy adaptive sky-hook gain is proposed to prevent the system from running out of energy, thereby eliminating the need to switch between passive and active systems. The results show that the system performs at least as well as a passive system for all frequencies, and is equivalent to an active system for a broad range of frequencies including both resonant frequencies.

Fail-Safe Vibration Control Using Active Force Generators

1983 ◽  
Vol 105 (3) ◽  
pp. 361-368 ◽  
Author(s):  
R. R. Guntur ◽  
S. Sankar
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Full Potential ◽  
Active Components ◽  
Active System ◽  
Performance Potential ◽  
Passive Components ◽  
Active Systems ◽  
Active Vibration ◽  
Fail Safe

Using the concept of force generators, various active vibration configurations have been examined for their performance potential. It is shown that an active vibration control system offers a great deal of flexibility in that by a proper choice of active components its transmissibility characteristics can be altered to suit the requirements. It is also shown how the full potential of active systems can be achieved even when there are passive components. An active system is designed in such a way that it gives the desired performance even in the event of the failure of the active components through the reliability offered by a passive system.

scholarly journals multiPDEVS: A Parallel Multicomponent System Specification Formalism

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Damien Foures ◽  
Romain Franceschini ◽  
Paul-Antoine Bisgambiglia ◽  
Bernard P. Zeigler
Keyword(s):  
Cellular Automata ◽  
Discrete Event ◽  
Multicomponent System ◽  
Fire Spread ◽  
Atomic Model ◽  
State Transitions ◽  
System Specification ◽  
Discrete Event System Specification ◽  
Simulation Procedure ◽  
Event System

Based on multiDEVS formalism, we introduce multiPDEVS, a parallel and nonmodular formalism for discrete event system specification. This formalism provides combined advantages of PDEVS and multiDEVS approaches, such as excellent simulation capabilities for simultaneously scheduled events and components able to influence each other using exclusively their state transitions. We next show the soundness of the formalism by giving a construction showing that any multiPDEVS model is equivalent to a PDEVS atomic model. We then present the simulation procedure associated, usually called abstract simulator. As a well-adapted formalism to express cellular automata, we finally propose to compare an implementation of multiPDEVS formalism with a more classical Cell-DEVS implementation through a fire spread application.

scholarly journals Modelling the role of LHCII-LHCII, PSII-LHCII and PSI-LHCII interactions in state transitions

2019 ◽  
Author(s):  
W. H. J. Wood ◽  
M. P. Johnson
Keyword(s):  
Monte Carlo ◽  
Protein Complex ◽  
Thylakoid Membrane ◽  
State Transition ◽  
Complex Dynamics ◽  
Light Harvesting ◽  
State Transitions ◽  
Antenna Size ◽  
Light Harvesting Antenna ◽  
Novel Algorithm

AbstractThe light-dependent reactions of photosynthesis take place in the plant chloroplast thylakoid membrane, a complex three-dimensional structure divided into the stacked grana and unstacked stromal lamellae domains. Plants regulate the macro-organization of photosynthetic complexes within the thylakoid membrane to adapt to changing environmental conditions and avoid oxidative stress. One such mechanism is the state transition which regulates photosynthetic light harvesting and electron transfer. State transitions are driven by changes in the phosphorylation of light harvesting antenna complex II (LHCII), which cause a decrease in grana diameter and stacking, a decreased energetic connectivity between photosystem II (PSII) reaction centres and an increase in the relative LHCII antenna size of photosystem I (PSI) compared to PSII. Phosphorylation is believed to drive these changes by weakening the intra-membrane lateral PSII-LHCII and LHCII-LHCII interactions and the inter-membrane stacking interactions between these complexes, while simultaneously increasing the affinity of LHCII for PSI. We investigated the relative roles and contributions of these three types of interaction to state transitions using a lattice-based model of the thylakoid membrane based on existing structural data, developing a novel algorithm to simulate protein complex dynamics. Monte Carlo simulations revealed that state transitions are unlikely to lead to a large-scale migration of LHCII from the grana to the stromal lamellae. Instead, the increased light harvesting capacity of PSI is largely due to the more efficient recruitment of LHCII already residing in the stromal lamellae into PSI-LHCII supercomplexes upon its phosphorylation. Likewise, the increased light harvesting capacity of PSII upon dephosphorylation was found to be driven by a more efficient recruitment of LHCII already residing in the grana into functional PSII-LHCII clusters, primarily driven by lateral interactions.Statement of significanceFor photosynthesis to operate at maximum efficiency the activity of the light-driven chlorophyll-protein complexes, photosystems I and II (PSI and PSII) must be fine-tuned to environmental conditions. Plants achieve this balance through a regulatory mechanism known as the state transition, which modulates the relative light-harvesting antenna size and therefore excitation rate of each photosystem. State transitions are driven by changes in the extent of the phosphorylation of light harvesting complex II (LHCII), which modulate the interactions between PSI, PSII and LHCII. Here we developed a novel algorithm to simulate protein complex dynamics and then ran Monte Carlo simulations to understand how these interactions cooperate to affect the organization of the photosynthetic membrane and bring about state transitions.

scholarly journals ACTIVE SYSTEM MANAGEMENT UNDER UNCERTAINTY

2014 ◽  
pp. 95-98
Author(s):  
G. Shakah ◽  
V. V. Krasnoproshin ◽  
A. N. Valvachev
Keyword(s):  
Set Theory ◽  
Fuzzy Set ◽  
Fuzzy Set Theory ◽  
System Management ◽  
Fuzzy Data ◽  
Active System ◽  
Active Systems ◽  
Distributed Organizations ◽  
Geographically Distributed ◽  
Unification Algorithms

The paper describes the use of fuzzy set theory and theory of active systems for constructing systems that manage geographically distributed organizations under uncertainty. Unification algorithms for fuzzy data and their use for choosing management of distant objects are presented.

scholarly journals Speeding Up Decision Support

2010 ◽  
pp. 255-273
Author(s):  
Navonil Mustafee ◽  
Simon J.E. Taylor ◽  
Korina Katsaliaki ◽  
Sally Brailsford
Keyword(s):  
Decision Support ◽  
Distributed Simulation ◽  
Discrete Event ◽  
Event Simulation ◽  
Healthcare Needs ◽  
Simulation Based ◽  
Long Time ◽  
Speed Up ◽  
Complex Health Problems ◽  
The Uk

Discrete-Event Simulation (DES) is a decision support technique that allows stakeholders to conduct experiments with models that represent real-world systems of interest. Its use in healthcare is comparatively new. Healthcare needs have grown and healthcare organisations become larger, more complex and more costly. There has never been a greater need for carefully informed decisions and policy. DES is valuable as it can provide evidence of how to cope with these complex health problems. However, the size of a healthcare system can lead to large models that can take an extremely long time to simulate. In this chapter the authors investigate how a technique called distributed simulation allows us to use multiple computers to speed up this simulation. Based on a case study of the UK National Blood Service they demonstrate the effectiveness of this technique and argue that it is a vital technique in healthcare informatics with respect to supporting decision making in large healthcare systems.

scholarly journals Demonstration of a relationship between state transitions and photosynthetic efficiency in a higher plant

2019 ◽  
Vol 476 (21) ◽  
pp. 3295-3312 ◽  
Author(s):  
Craig R. Taylor ◽  
Wim van Ieperen ◽  
Jeremy Harbinson
Keyword(s):  
Photosynthetic Efficiency ◽  
State Transition ◽  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
State Transitions ◽  
Short Term ◽  
Higher Plant ◽  
Series Configuration ◽  
Use Efficiency ◽  
Sun And Shade

A consequence of the series configuration of PSI and PSII is that imbalanced excitation of the photosystems leads to a reduction in linear electron transport and a drop in photosynthetic efficiency. Achieving balanced excitation is complicated by the distinct nature of the photosystems, which differ in composition, absorption spectra, and intrinsic efficiency, and by a spectrally variable natural environment. The existence of long- and short-term mechanisms that tune the photosynthetic apparatus and redistribute excitation energy between the photosystems highlights the importance of maintaining balanced excitation. In the short term, state transitions help restore balance through adjustments which, though not fully characterised, are observable using fluorescence techniques. Upon initiation of a state transition in algae and cyanobacteria, increases in photosynthetic efficiency are observable. However, while higher plants show fluorescence signatures associated with state transitions, no correlation between a state transition and photosynthetic efficiency has been demonstrated. In the present study, state 1 and state 2 were alternately induced in tomato leaves by illuminating leaves produced under artificial sun and shade spectra with a sequence of irradiances extreme in terms of PSI or PSII overexcitation. Light-use efficiency increased in both leaf types during transition from one state to the other with remarkably similar kinetics to that of F′m/Fm, F′o/Fo, and, during the PSII-overexciting irradiance, ΦPSII and qP. We have provided compelling evidence for the first time of a correlation between photosynthetic efficiency and state transitions in a higher plant. The importance of this relationship in natural ecophysiological contexts remains to be elucidated.

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