scholarly journals Analysis and Design of the Battery Initial Energy Level with Task Scheduling for Energy-Harvesting Embedded Systems

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xingyu Miao ◽  
Jiayuan Wei ◽  
Yongqi Ge
Keyword(s):  
Energy Harvesting ◽  
Energy Level ◽  
Initial Energy ◽  
Success Rates ◽  
Worst Case ◽  
Task Set ◽  
Analysis And Design ◽  
Available Energy ◽  
Battery Capacity ◽  
Task Sets

When the energy-harvesting embedded system (EHES) is running, its available energy (harvesting energy and battery storage energy) seems to be sufficient overall. However, in the process of EHES task execution, an energy shortage may occur in the busy period such that system tasks cannot be scheduled. We call this issue the energy deception (ED) of the EHES. Aiming to address the ED issue, we design an appropriate initial energy level of the battery. In this paper, we propose three algorithms to judge the feasibility of the task set and calculate the appropriate initial energy level of the battery. The holistic energy evaluation (HEE) algorithm makes a preliminary judgment of the task set feasibility according to available energy and consumption energy. A worst-case response time-based initial energy level of the battery (WCRT-IELB) algorithm and an accurate cycle-initial energy level of the battery (AC-IELB) algorithm can calculate the proper initial battery capacity. We use the YARTISS tool to simulate the above three algorithms. We conducted 250 experiments on As Late As Possible (ALAP) and As Soon As Possible (ASAP) scheduling with the maximum battery capacities of 50, 100, 200, 300, and 400. The experimental results show that setting a reasonable initial energy level of the battery can effectively improve the feasibility of the task set. Among the 250 task sets, the HEE algorithm filtered 2.8% of them as infeasible task sets. When the battery capacity is set to 400, the WCRT-BIEL algorithm increases the success rates of the ALAP and ASAP by 17.2% and 26.8%, respectively. The AC-BIEL algorithm increases the success rates of the ALAP and ASAP by 18% and 26.8%, respectively.

scholarly journals No-go trials in task switching: effects on the task-set and task-space level

2021 ◽  
Author(s):  
Juliane Scheil ◽  
Thomas Kleinsorge
Keyword(s):  
Task Switching ◽  
The Other ◽  
Specific Task ◽  
Task Space ◽  
Response Level ◽  
Task Set ◽  
Common Marker ◽  
Task Sets ◽  
And Task

AbstractA common marker for inhibition processes in task switching are n − 2 repetition costs. The present study aimed at elucidating effects of no-go trials on n − 2 repetition costs. In contrast to the previous studies, no-go trials were associated with only one of the three tasks in the present two experiments. High n − 2 repetition costs occurred if the no-go task had to be executed in trial n − 2, irrespective of whether a response had to be withheld or not. In contrast, no n − 2 repetition costs were visible if the other two tasks were relevant in n − 2. Whereas this n − 2 effect was unaffected by whether participants could reliably exclude a no-go trial or not, effects of no-gos in trial n were determined by this knowledge. The results differ from effects of no-go trials that are not bound to a specific task. It is assumed that the present no-go variation exerted its effect not on the response level, but on the level of task sets, resulting in enhanced salience of the no-go task that leads to higher activation and, as a consequence, to stronger inhibition. The dissociation of the effects on no-gos in trials n − 2 and n as a function of foreknowledge suggests that the balance between activation and inhibition is shifted not only for single trials and tasks, but for the whole task space.

Learning of across- and within-task contingencies modulates partial-repetition costs in dual-tasking

2021 ◽  
Author(s):  
Lasse Pelzer ◽  
Christoph Naefgen ◽  
Robert Gaschler ◽  
Hilde Haider
Keyword(s):  
Dual Task ◽  
Discrimination Task ◽  
Experimental Approach ◽  
Feature Binding ◽  
Dual Tasking ◽  
Single Task ◽  
Task Set ◽  
Task Processing ◽  
Tone Discrimination ◽  
Task Sets

AbstractDual-task costs might result from confusions on the task-set level as both tasks are not represented as distinct task-sets, but rather being integrated into a single task-set. This suggests that events in the two tasks are stored and retrieved together as an integrated memory episode. In a series of three experiments, we tested for such integrated task processing and whether it can be modulated by regularities between the stimuli of the two tasks (across-task contingencies) or by sequential regularities within one of the tasks (within-task contingencies). Building on the experimental approach of feature binding in action control, we tested whether the participants in a dual-tasking experiment will show partial-repetition costs: they should be slower when only the stimulus in one of the two tasks is repeated from Trial n − 1 to Trial n than when the stimuli in both tasks repeat. In all three experiments, the participants processed a visual-manual and an auditory-vocal tone-discrimination task which were always presented concurrently. In Experiment 1, we show that retrieval of Trial n − 1 episodes is stable across practice if the stimulus material is drawn randomly. Across-task contingencies (Experiment 2) and sequential regularities within a task (Experiment 3) can compete with n − 1-based retrieval leading to a reduction of partial-repetition costs with practice. Overall the results suggest that participants do not separate the processing of the two tasks, yet, within-task contingencies might reduce integrated task processing.

Energy Harvesting With Piezoelectric Nanobrushes: Analysis and Design Principles

2009 ◽  
Author(s):  
Carmel Majidi ◽  
Mikko Haataja ◽  
David J. Srolovitz
Keyword(s):  
Energy Harvesting ◽  
Design Space ◽  
Electronic Devices ◽  
Wearable Electronics ◽  
Nanostructured Surface ◽  
Elastic Rod ◽  
Analysis And Design ◽  
Rod Theory ◽  
Piezoelectric Energy ◽  
Self Powered

The development of self-powered electronic devices is essential for emerging technologies such as wireless sensor networks, wearable electronics, and microrobotics. Of particular interest is the rapidly growing field of piezoelectric energy harvesting (PEH), in which mechanical strains are converted to electricity. Recently, PEH has been demonstrated by brushing an array of piezoelectric nanowires against a nanostructured surface. The piezoelectric nanobrush generator can be limited to sub-micron dimensions and thus allows for a vast reduction in the size of self-powered devices. Moreover, energy harvesting is controlled through contact between the nanowire tips and nanostructured surface, which broadens the design space to a wealth of innovations in tribology. Here we propose design criteria based on principles of contact mechanics, elastic rod theory, and continuum piezoelasticity.

scholarly journals Global existence and nonexistence for a class of finitely degenerate coupled parabolic systems with high initial energy level

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Yuxuan Chen ◽  
Jiangbo Han
Keyword(s):  
Energy Level ◽  
Global Existence ◽  
Blow Up ◽  
Parabolic Systems ◽  
Initial Energy ◽  
Blowup Time ◽  
Positive Initial Energy ◽  
Existence And Nonexistence ◽  
Nonexistence Of Solutions ◽  
Coupled Parabolic Systems

<p style='text-indent:20px;'>In this paper, we consider a class of finitely degenerate coupled parabolic systems. At high initial energy level <inline-formula><tex-math id="M1">\begin{document}$ J(u_{0})&gt;d $\end{document}</tex-math></inline-formula>, we present a new sufficient condition to describe the global existence and nonexistence of solutions for problem (1)-(4) respectively. Moreover, by applying the Levine's concavity method, we give some affirmative answers to finite time blow up of solutions at arbitrary positive initial energy <inline-formula><tex-math id="M2">\begin{document}$ J(u_{0})&gt;0 $\end{document}</tex-math></inline-formula>, including the estimate of upper bound of blowup time.</p>

scholarly journals Spontaneous task structure formation results in a cost to incidental memory of task stimuli

2018 ◽  
Author(s):  
Christina Bejjani ◽  
Tobias Egner
Keyword(s):  
Structure Formation ◽  
Structure Learning ◽  
Learning Task ◽  
Underlying Structure ◽  
Task Structure ◽  
Cognitive Demands ◽  
Task Set ◽  
Stimulus Response ◽  
Attention To Task ◽  
Task Sets

Humans are characterized by their ability to leverage rules for classifying and linking stimuli to context-appropriate actions. Previous studies have shown that when humans learn stimulus-response associations for two-dimensional stimuli, they implicitly form and generalize hierarchical rule structures (task-sets). However, the cognitive processes underlying structure formation are poorly understood. Across four experiments, we manipulated how trial-unique images mapped onto responses to bias spontaneous task-set formation and investigated structure learning through the lens of incidental stimulus encoding. Participants performed a learning task designed to either promote task-set formation (by “motor-clustering” possible stimulus-action rules), or to discourage it (by using arbitrary category-response mappings). We adjudicated between two hypotheses: Structure learning may promote attention to task stimuli, thus resulting in better subsequent memory. Alternatively, building task-sets might impose cognitive demands (for instance, on working memory) that divert attention away from stimulus encoding. While the clustering manipulation affected task-set formation, there were also substantial individual differences. Importantly, structure learning incurred a cost: spontaneous task-set formation was associated with diminished stimulus encoding. Thus, spontaneous hierarchical task-set formation appears to involve cognitive demands that divert attention away from encoding of task stimuli during structure learning.

scholarly journals Contextual Adaptation of Cognitive Flexibility is driven by Task- and Item-Level Learning

2019 ◽  
Author(s):  
Audrey Siqi-Liu ◽  
Tobias Egner
Keyword(s):  
Cognitive Flexibility ◽  
Stimulus Item ◽  
Transfer Task ◽  
Learning Mechanisms ◽  
Behavioral Experiments ◽  
Task Set ◽  
Switch Costs ◽  
Cognitive Stability ◽  
Current Task ◽  
Task Sets

Adaptive behavior requires finding, and adjusting, an optimal tradeoff between focusing on a current task-set (cognitive stability) and updating that task-set when the environment changes (cognitive flexibility). Such dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, where switch costs tend to decrease as the proportion of switch trials over blocks increases. However, the learning mechanisms underlying this phenomenon, here referred to as the list-wide proportion switch effect (LWPSE), are currently unknown.We addressed this question across four behavioral experiments. Experiment 1 replicated the basic LWPSE reported in previous studies. Having participants switch between three instead of two tasks, Experiment 2 demonstrated that the LWPSE is preserved even when the specific alternate task to switch to cannot be anticipated. Experiments 3a and 3b tested for the generalization of list-wide switch-readiness to an unbiased “transfer task,” presented equally often as switch and repeat trials, by intermixing the transfertask with biased tasks. Despite the list-wide bias, the LWPSE was only found for biased tasks, suggesting that the modulations of switch costs are task set and/or task stimulus (item)-specific. To evaluate these two possibilities, Experiment 4 employed biased versus unbiased stimuli within biased task sets and found switch-cost modulations for both stimuli sets. These results establish how people adapt their stability-flexibility tradeoff to different contexts. Specifically, our findings show that people learn to associate context appropriate levels of switch readiness with switch-predictive cues, provided by task sets as well as specific task stimuli.

Optimal operating point for energy harvesting from microbial fuel cell with finite initial energy

2018 ◽  
Vol 400 ◽  
pp. 183-189
Author(s):  
Jae-Do Park ◽  
Md Habib Ullah ◽  
Timberley M. Roane ◽  
Muhannad Alaraj ◽  
Feng Shuo
Keyword(s):  
Fuel Cell ◽  
Energy Harvesting ◽  
Microbial Fuel Cell ◽  
Initial Energy ◽  
Operating Point ◽  
Optimal Operating

scholarly journals On-Site and External Energy Harvesting in Underground Wireless

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 681 ◽  
Author(s):  
Usman Raza ◽  
Abdul Salam
Keyword(s):  
Energy Harvesting ◽  
Wireless Power Transfer ◽  
Energy Sources ◽  
Power Transfer ◽  
Wireless Power ◽  
External Energy ◽  
Term Operation ◽  
Available Energy ◽  
Underground Communication

Energy efficiency is vital for uninterrupted long-term operation of wireless underground communication nodes in the field of decision agriculture. In this paper, energy harvesting and wireless power transfer techniques are discussed with applications in underground wireless communications (UWC). Various external wireless power transfer techniques are explored. Moreover, key energy harvesting technologies are presented that utilize available energy sources in the field such as vibration, solar, and wind. In this regard, the Electromagnetic (EM)- and Magnetic Induction (MI)-based approaches are explained. Furthermore, the vibration-based energy harvesting models are reviewed as well. These energy harvesting approaches lead to design of an efficient wireless underground communication system to power underground nodes for prolonged field operation in decision agriculture.

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