Increased Response Speed Research Articles

Comparison Performance of PI and FPI Controllers for Model Reduction of Binary Distillation Column Plant

Distillation is the separation strategy in the oil and compound businesses for cleansing of conclusive items. This paper deals with the reduced dynamic model and control of the distillation tower by applying a multi-loop control framework in Matlab/Simulink for a double blend. The structure objective considered is to guarantee that the top item, the base item, the reflux rate and the reboiler rate stray inside their recommended limits forever and for all the aggravations. This paper proposes an optimal tuning method for fractional Proportional-Integral controller (FPI). The method consists of minimizing Integral Absolute Error (IAE) performance index criterion. Acceptable controller (FPI) is acquired via looking in the space of plan boundaries (Kp,Ki). An example of application (distillation column) plant is presented to evaluate the proposed method. A comparison with classical PI controller and optimal PI shows that the system under fractional state is robust in terms of transient specifications, maximum overshot, settling and rise times. The simulation results shows that more than (21%) improvement for reducing the max-overshot and(65%)improvement for increasing response speed for fractional PI compared with classical PI.MATLAB simulation toolbox is used to show the effectives of the proposed method.

Sliding mode control of permanent magnet generator system based on improved exponential rate reaching law

This study focuses on the improvement in the transient performance of DC-link voltage for a permanent magnet generator (PMG) system. Based on the vector control theory and double closed-loop control, the sliding mode control (SMC) method with the improved exponential rate reaching law (IERRL) is proposed in the voltage loop of the PMG system. The switching surface is designed with an integral term of state variable to suppress chattering and increase response speed. In addition, the IERRL that combines the concept of constant-proportional rate reaching law and exponential reaching law is proposed to further suppress chattering and eliminate steady-state tracking error of DC-link voltage. A detailed analysis of control law, system stability, reaching time, and chattering on switching surfaces are presented as well. The SMC method with IERRL improves the transient performance under sudden load changing occasion and eliminates the steady-state tracking error of DC-link voltage. Simulation and experimental results verify the effectiveness of the proposed method.

Simplified swarm optimization for optimal deployment of fog computing system of industry 4.0 smart factory

Fog computing is an emerging technology that can reduce the load on cloud system and decentralize computing resource, thus increasing response speed and reducing time delay. More and More environments in order to achieve intelligence, collect massive amounts of data though IOT devices. Considering deploying fog computing system in these environments can make system faster and more robust. This work creates a simulated factory consisting of a cloud center, gateways, fog devices, edge devices, and different types of sensors. We build an integer programming model and apply metaheuristic method for determining the layout of above devices except of cloud center and all sensors so that can find the cost minimization deployment of the smart factory.

Beta power encodes contextual estimates of temporal event probability in the human brain.

To prepare for an impending event of unknown temporal distribution, humans internally increase the perceived probability of event onset as time elapses. This effect is termed the hazard rate of events. We tested how the neural encoding of hazard rate changes by providing human participants with prior information on temporal event probability. We recorded behavioral and electroencephalographic (EEG) data while participants listened to continuously repeating five-tone sequences, composed of four standard tones followed by a non-target deviant tone, delivered at slow (1.6 Hz) or fast (4 Hz) rates. The task was to detect a rare target tone, which equiprobably appeared at either position two, three or four of the repeating sequence. In this design, potential target position acts as a proxy for elapsed time. For participants uninformed about the target’s distribution, elapsed time to uncertain target onset increased response speed, displaying a significant hazard rate effect at both slow and fast stimulus rates. However, only in fast sequences did prior information about the target’s temporal distribution interact with elapsed time, suppressing the hazard rate. Importantly, in the fast, uninformed condition pre-stimulus power synchronization in the beta band (Beta 1, 15–19 Hz) predicted the hazard rate of response times. Prior information suppressed pre-stimulus power synchronization in the same band, while still significantly predicting response times. We conclude that Beta 1 power does not simply encode the hazard rate, but—more generally—internal estimates of temporal event probability based upon contextual information.

A Study on Aero-Engine Direct Thrust Control with Nonlinear Model Predictive Control Based on Deep Neural Network

For enhancing engine response ability, a novel nonlinear model predictive control (NMPC) method for aero-engine direct thrust control is proposed. The control objective of the proposed method is the thrust instead of the measurable parameters. The online-sliding window deep neural network (OL-SW-DNN) is proposed as predictive model. The OL-SW-DNN adopts deep-learning structure to increase the model accuracy and selects the nearest point data of certain length as training data which will reduce the sensitivity for the noise of training data. The direct thrust simulations of the popular NMPC based on extended Kalman filler (EKF) and the proposed one are conducted, respectively. The simulations demonstrate that compared with the popular NMPC, the proposed NMPC decreases the acceleration time by 0.425 s and increases response speed about 1.14 times.

Mild acute stress improves response speed without impairing accuracy or interference control in two selective attention tasks: Implications for theories of stress and cognition

Acute stress is generally thought to impair performance on tasks thought to rely on selective attention. This effect has been well established for moderate to severe stressors, but no study has examined how a mild stressor—the most common type of stressor—influences selective attention. In addition, no study to date has examined how stress influences the component processes involved in overall selective attention task performance, such as controlled attention, automatic attentional activation, decision-making, and motor abilities. To address these issues, we randomly assigned 107 participants to a mild acute stress or control condition. As expected, the mild acute stress condition showed a small but significant increase in cortisol relative to the control condition. Following the stressor, we assessed attention with two separate flanker tasks. One of these tasks was optimized to investigate component attentional processes using computational cognitive modeling, whereas the other task employed mouse-tracking to illustrate how response conflict unfolded over time. The results for both tasks showed that mild acute stress decreased response time (i.e., increased response speed) without influencing accuracy or interference control. Further, computational modeling and mouse-tracking analyses indicated that these effects were due to faster motor action execution time for chosen actions. Intriguingly, however, cortisol responses were unrelated to any of the observed effects of mild stress. These results have implications for theories of stress and cognition, and highlight the importance of considering motor processes in understanding the effects of stress on cognitive task performance.

Debye-length controlled gas sensing performances in NiO@ZnO p-n junctional core–shell nanotubes

To enhance gas sensing performance, constructing p-n heterostructures are considered as a promising route for designing high-performance gas sensing materials due to their synergistic and p-n junction effects. In particular, the shell layers’ thickness often plays a vital role in the modulation of carrier transport during the gas sensing processes. In this work, we have designed a type of NiO@ZnO core–shell nanotube (CSNT) with a thickness-tuneable shell by combining electrospinning with atomic layer deposition (ALD) techniques. The results showed that the NiO@ZnO composite nanofibers possessed a uniform tubular structure and comprised of a 230 nm polycrystalline NiO core and a wrinkled porous ZnO shell with a tuneable thickness (0–50 nm) via ALD cycles. Also, gas sensing tests showed that the NiO@ZnO CSNTs with shell thickness close to the Debye length showed the highest gas sensitivity, e.g. the response to 100 ppm ethanol was 15.8, which is ~6.5 times that of the pure NiO. Moreover, the assembled sensors also showed excellent stability (almost keeping 100% after 1 month tests), increased response speed and improved gas selectivity. Furthermore, based on our series of tests and analysis, a possible gas sensing enhancement mechanism (Debye-length controlled gas sensing mechanism) has been proposed for the gas sensing behaviours of our designed sensors based on NiO@ZnO CSNTs.

Coordination-Driven Self-Assembled Metallacycles Incorporating Pyrene: Fluorescence Mutability, Tunability, and Aromatic Amine Sensing.

Constructing polycyclic aromatics-based, highly emissive fluorophores with good solubility and tunable aggregated structures and properties is of great importance for film fabrication, solution processing, and relevant functionality studies. Herein, we describe a general strategy to endow conventional organic fluorophores with enhanced solubility and modulated fluorescent properties via their incorporation into coordination-driven self-assembled metallacycles. A widely used fluorophore, pyrene, was decorated with two pyridyl groups to yield functionalized pyrene 4. Mixing 4 with three aromatic dicarboxylates with different lengths and a 90° Pt(II) metal acceptor in a 2:2:4 stoichiometric ratio resulted in the formation of three metallacycles, 1, 2, and 3. The metallacycles display good solubility in polar organic solvents, highly aggregation-dependent fluorescence, and size-dependent emissions at higher concentrations. Moreover, metallacycle 2-based, silica-gel-supported film as fabricated not only is more emissive than the ligand 4-based one but also displays much improved sensing properties for amines in the vapor state, as demonstrated by significantly increased response speed and decreased recovery time. The enhanced solubility, unique fluorescence behavior, and multi-factor modulation character show that coordination-driven self-assembly can be utilized for the development of new fluorophores through simple modification of conventional fluorophores. The fluorophores synthesized this way possess not only complex topological structures but also good modularity and tunability in fluorescence behavior, which are important for grafting multi-stage energy-transfer systems necessary for the development of high-performance sensing materials.

Modulating proactive cognitive control by reward: differential anticipatory effects of performance-contingent and non-contingent rewards

The present study investigated the influences of two different forms of reward presentation in modulating cognitive control. In three experiments, participants performed a flanker task for which one-third of trials were precued for a chance of obtaining a reward (reward trials). In Experiment 1, a reward was provided if participants made the correct response on reward trials, but a penalty was given if they made an incorrect response on these trials. The anticipation of this performance-contingent reward increased response speed and reduced the flanker effect, but had little influence on the sequential modulation of the flanker effect after incompatible trials. In Experiment 2, participants obtained a reward randomly on two-thirds of the precued reward trials and were given a penalty on the remaining one-third, regardless of their performance. The anticipation of this non-contingent reward had little influence on the overall response speed or flanker effect, but reduced the sequential modulation of the flanker effect after incompatible trials. Experiment 3 also used performance non-contingent rewards, but participants were randomly penalized more often than they were rewarded; non-contingent penalty had little influence on the sequential modulation of the flanker effect. None of the three experiments showed a reliable influence of the actual acquisition of rewards on task performance. These results indicate anticipatory effects of performance-contingent and non-contingent rewards on cognitive control with little evidence of aftereffects.

Subthalamic nucleus stimulation, dopaminergic treatment and impulsivity in Parkinson's disease

BackgroundDeep brain stimulation of the subthalamic nucleus (STN DBS) is known to increase response speed and lower response accuracy in Parkinson's disease (PD) patients. It has been proposed that this speed-accuracy tradeoff is due to enhanced sensitivity of the motor system to sensory information. An alternative possibility is that this effect is due to weakened suppressive processes. The two alternative interpretations can be tested by analyzing the electromyographic activity (EMG) of the response agonists when the patients perform conflict reaction time tasks. In those tasks, fast subthreshold muscle impulses often occur in the agonist of the incorrect response. These impulses are partial errors that are suppressed before being behaviourally committed. Material and methodsHere we analyzed the EMG of the response agonists recorded while sixteen PD patients performed a Simon task that elicits prepotent response tendencies so as to decipher (i) whether STN DBS affects the expression and/or suppression of subthreshold muscle impulses that are critical for action control and (ii) the interaction between dopaminergic treatment and STN DBS. The patients were tested On and Off STN DBS and On and Off dopaminergic medication in a full factorial design. ResultsSTN DBS not only impaired the proficiency to suppress subliminal action impulses (p = 0.01) but also favoured the muscular expression of fast incorrect impulses (p < 0.001). Dopaminergic treatment only affected the action impulses suppression (p = 0.02) and did not change the effect of STN DBS on impulsive action control. ConclusionContrary to a recent proposal, STN DBS impaired rather than improved action control by weakening erroneous impulse suppression, whether the patients were On or Off their usual medication. These findings are discussed in light of a recent proposal (Servant M, White C, Montagnini A, Burle B, 2015) that reconciles partial errors with accumulation-to-bound models of decision making. Our results suggest that medication specifically lowers the mechanical threshold while STN DBS lowers the mechanical threshold and to a lesser extent the EMG-threshold.

Implications of Thermal Annealing on the Benzene Vapor Sensing Behavior of PEVA-Graphene Nanocomposite Threads.

The effect of thermal treatments, on the benzene vapor sensitivity of polyethylene (co-)vinylacetate (PEVA)/graphene nanocomposite threads, used as chemiresistive sensors, was investigated using DC resistance measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). These flexible threads are being developed as low-cost, easy-to-measure chemical sensors that can be incorporated into smart clothing or disposable sensing patches. Chemiresistive threads were solution-cast or extruded from PEVA and <10% graphene nanoplatelets (by mass) in toluene. Threads were annealed at various temperatures and showed up to 2 orders of magnitude decrease in resistance with successive anneals. Threads heated to ≥80 °C showed improved limits of detection, resulting from improved signal-noise, when exposed to benzene vapor in dry air. In addition, annealing increased the speed of response and recovery upon exposure to and removal of benzene vapor. DSC results showed that the presence of graphene raises the freezing point, and may allow greater crystallinity, in the nanocomposite after annealing. SEM images confirm increased surface roughness/area, which may account for the increase response speed after annealing. Benzene vapor detection at 5 ppm is demonstrated with limits of detection estimated to be as low as 1.5 ppm, reflecting an order of magnitude improvement over unannealed threads.

Effects of -12° head-down tilt with and without elevated levels of CO2 on cognitive performance: the SPACECOT study.

Microgravity and elevated levels of CO2 are two common environmental stressors in spaceflight that may affect cognitive performance of astronauts. In this randomized, double-blind, crossover trial (SPACECOT), 6 healthy males (mean ± SD age: 41 ± 5 yr) were exposed to 0.04% (ambient air) and 0.5% CO2 concentrations during 26.5-h periods of -12° head-down tilt (HDT) bed rest with a 1-wk washout period between exposures. Subjects performed the 10 tests of the Cognition Test Battery before and on average 0.1, 5.2, and 21.0 h after the initiation of HDT bed rest. HDT in ambient air induced a change in response strategy, with increased response speed (+0.19 SD; P = 0.0254) at the expense of accuracy (-0.19 SD; P = 0.2867), resulting in comparable cognitive efficiency. The observed effects were small and statistically significant for cognitive speed only. However, even small declines in accuracy can potentially cause errors during mission-critical tasks in spaceflight. Unexpectedly, exposure to 0.5% CO2 reversed the response strategy changes observed under HDT in ambient air. This was possibly related to hypercapnia-induced cerebrovascular reactivity that favors cortical regions in general and the frontal cortex in particular, or to the CNS arousing properties of mildly to moderately increased CO2 levels. There were no statistically significant time-in-CO2 effects for any cognitive outcome. The small sample size and the small effect sizes are major limitations of this study and its findings. The results should not be generalized beyond the group of investigated subjects until they are confirmed by adequately powered follow-up studies. NEW & NOTEWORTHY Simulating microgravity with exposure to 21 h of -12° head-down tilt bed rest caused a change in response strategy on a range of cognitive tests, with a statistically significant increase in response speed at the expense of accuracy. Cognitive efficiency was not affected. The observed speed-accuracy tradeoff was small but may nevertheless be important for mission-critical tasks in spaceflight. Importantly, the change in response strategy was reversed by increasing CO2 concentrations to 0.5%.

Photodetectors based on two-dimensional semiconductors: Progress, opportunity and challenge

Two-dimensional (2D) materials have attracted increasingly great interest in recent years due to their unique structures and novel physical and chemical properties. 2D semiconductors, the brightest member of the family of 2D materials, allow for realizing versatile electronic and optoelectronic devices. Their layered structure and atomic thickness render them have promising applications in monolithic integration, flexible devices and wearables electronics. Moreover, their bandgaps are usually related to the thickness and external strain, which mean the electronic optoelectronic properties can be tuned by changing the number of layers or strain engineering. Interestingly, some 2D semiconductors such as black phosphorus, GeS, and ReS2 have low symmetry crystal structures, their electronic and optical properties are highly anisotropic, such characteristics give us another degree of freedom to photodetections using polarized light. This feature article reviews the recent research activities that focus on applications of 2D semiconductors as photodetectors. It begins with survey of photocurrent generation mechanisms, which include photoconductive effect, photogating effect, photovoltaic effect, photo-thermoelectric effect and bolometric effect. These mechanisms are systematically introduced and discussed. Then, the general meaning of figure of merit that evaluates the performance of photodetectors is introduced, including responsivity, external quantum efficiency, time response, signal to noise ratio, noise equivalent power, detectivity. Furthermore, the recent photodetectors based on 2D semiconductors including transition metal dichalcogenides (TMDs), black phosphorus, ternary chalcogenides and their hybrid structures such as 2D-0D, 2D-1D, 2D-2D and 2D-3D structures are presented. MoS2 is the most studied TMD semiconductor, photodetectors based on monolayer and multilayers MoS2 are widely studied, some strategies including doping, encapsulation, and device design for improving photoelectronic performance are presented. Another interesting TMD is ReS2, due to its direct bandgap nature regardless of thickness and the low symmetry structure, it is supposed to have promising optoelectronic properties including in plane anisotropy. Black phosphorus, a p-type direct bandgap semiconductor with ultrahigh room temperature mobility beyond 1000 cm2/V s, have also received much attentions in recent years. Unlike most 2D semiconductor have bandgap range from 1–2 eV, black phosphorus have a much wide tunable bandgap from 0.3–1.5 eV, depending on the thickness, which means it can be used for infrared detection. Besides, like ReS2, black phosphorus also have in plane anisotropy in optic and electronic properties, proving us another additional opportunity by using polarization techniques to control the photoelectronic properties. The no dangling bonds nature at surface of 2D materials make the mixing of 2D materials with each other and other materials possible without the constraints of crystal lattice matching possible. These 2D based hybrid structures are also used in photodetectors to broaden the response range, increase response speed, and even investigate new physics. The most challenges of 2D semiconducting photodetectors are the low absorptions, slow response and narrow detect range. We also summarize some strategies to improve the above mentioned problems. Plasmon antenna, optical waveguides and optical microcavities can help to improve light absorption of 2D semiconductors. p-n Diode devices not only have fast response, but also wide detect range, other strategies such as encapsulation, surface modification, electrode design and so on might also help. Finally, the article ends with a summary and outlook on the future developments in this growing field.

Adjusting Synchronverter Dynamic Response Speed via Damping Correction Loop

This paper proposes to augment the conventional synchronverter control scheme with an auxiliary loop to freely adjust the dynamic response speed. This loop is dubbed as a damping correction loop since its form and function are reminiscent of the damping component in the classical synchronous generator model. Central to the proposed auxiliary loop is the creation of an additional tuneable parameter that allows for unrestricted adjustment of the system damping ratio without affecting the steady-state frequency droop characteristic, which is an improvement over the conventional synchronverter design. In the proposed method, relevant parameters are analytically tuned and active- and reactive-power coupling effects are reduced when operating with increased response speed. The dynamic response and robustness of the approach are verified via extensive small-signal analysis. Furthermore, time-domain simulations highlight the advantages of the proposed method over existing ones.

INCREASE THE SPEED OF WEB APPLICATIONS

The article presents a method of creating a web application based on SPA technology (one-page web application), as a method of increasing the speed of web applications based on the use of modern frameworks, tools and tools for developing client and server part of a one-page web application. One-page web applications are web application technologies that consist of a single web page that interacts with the user, dynamically generating the current page rather than downloading entire new pages from the server. Based on this technique, we developed our own web application and based on it we determined the response rate, which is less than the optimal response rate for single-page web applications. An explanation is given as to which solutions increase response speed and performance in a one-page web application, and why creating a multi-page site is not the best idea. Keywords: single-page web application, database, multi-page web application, non-relational database, relational database, Backend technologies, server, JavaScript

Multi-Agent-Based Controller for Voltage Enhancement in AC/DC Hybrid Microgrid Using Energy Storages

Development of renewable energies and DC loads have led microgrids toward the creation of DC networks. The predictions show that the hybrid microgrids will be used widely in the future. This article has studied the voltage stability in the presence of sources of energy storage in AC/DC hybrid networks. However, because the different dynamics of hybrid networks applying centralized and distributed controllers will be faced with different problems, in this study, a multi-agent control for the microgrid has been used. A new structure referred to here as an event-driven microgrid control management (EDMCM) has been developed to control the microgrid. This method increases response speed and accuracy of decision making. Hybrid Network Simulation results confirm the validity of the developed model.

Beyond decision! Motor contribution to speed-accuracy trade-off in decision-making.

Both in real life and experimental settings, increasing response speed typically leads to more error-prone actions. Processes underlying such a "speed-accuracy trade-off" (SAT) are usually assumed to be purely decisional: cautiousness would be determined only by the amount of sensory evidence required to select a response. The present data challenges this largely accepted view, by directly showing that motor processes are speeded up under time pressure. In a choice reaction time task where emphasis was put either on response speed or accuracy, motor processes were investigated through the analysis of muscular activity related to response execution. When response speed was emphasized, the time between electromyographic onset and behavioral response (motor time) was also speeded up (contributing to more than 20 % of the total effect on global reaction time). This speeded execution (likely due to a more efficient motor command) may also explain why participants are less able to interrupt incorrect response execution once started (Burle et al., Psychonomic Bulletin & Review, 21(4), 1003-1010, 2014), leading to more overt errors. Pointing to a speed-accuracy exchange within motor processes themselves, the present results call for a re-evaluation of widely accepted assumptions about SAT, and more generally, decision-making processes. They are discussed in the context of recent extensions of the drift diffusion model framework, questioning the strict separation between decisional and motor processes.

Male Smokers' and Non-Smokers' Response Inhibition in Go/No-Go Tasks: Effect of Three Task Parameters

Impaired response inhibition plays a major role in many addictive behaviors. However, in studies using go/no-go tasks, findings regarding the presence of response inhibition deficits in nicotine-dependent individuals are mixed. This might be due to differences between studies on a number of task parameters. Here we aimed to identify task conditions under which go/no-go task performance deficits can be observed in smokers and to characterize the nature of such deficits. Sixty-one male students (30 smokers, 31 non-smokers) performed a go/no-go task while independently manipulating three task parameters: (1) percentage no-go trials (50% or 25%), (2) stimulus presentation time (600 ms or 200 ms), and (3) nature of no-go stimuli (cigarette related or cigarette unrelated). Three measures, reaction time on go trials and percentage correct responses on go and no-go trials, served as performance indicators. Under 200-ms but not 600-ms stimulus presentation conditions, the smokers responded faster on go trials and made more errors on both go and no-go trials than the non-smokers did. These differences occurred irrespective of the percentage of no-go trials and nature of no-go stimuli. The accuracy differences disappeared after controlling for the response time differences, suggesting a strong speed-accuracy trade-off. This study contributes to unraveling the conditions under which smokers display impaired inhibition performance and helps to characterize the nature of this impairment. Under task conditions prompting fast responding, smokers are more prone to increase response speed and to make more errors than non-smokers.

Design and application of a new control system for tokamak ECRH power supply

ABSTRACTThe biggest challenge of designing and building tokamak electron cyclotron resonance heating (ECRH) pulse step modulation (PSM) power supply is satisfying its required output voltage rising time to be less than 100 µs while suppressing the voltage overshoot to be no more than 1%. To fulfill the two requirements, a new control strategy with startup time in microsecond range is proposed in this paper, and a new control system to realize the control strategy is introduced. The control system was built and tested on 60 kV/50 A ECRH power supply. The experimental results indicate that the control system can restrain the overshoot effectively, increase response speed, and obviously improve the dynamic characteristics of the PSM power supply system. Thus, the proposed control system helps the PSM power supply to meet the design specifications.

Sex Differences and the Impact of Chronic Stress and Recovery on Instrumental Learning.

We have previously shown that 21-day chronic restraint stress impacts instrumental learning, but overall few studies have examined sex differences on the impact of stress on learning. We further examined sex differences in response to extended 42-day chronic stress on instrumental learning, as well as recovery from chronic stress. Rats were tested in aversive training tasks with or without prior appetitive experience, and daily body weight data was collected as an index of stress. Relative to control animals, reduced body weight was maintained from day 22 through day 42 across the stress period for males, but not for females. Stressed males had increased response speed and lower learning efficiency during appetitive acquisition and aversive learning. Males overall showed slower escape shaping times and more shock exposure. In contrast, stressed females showed slower appetitive response speeds and higher appetitive and aversive efficiency but overall reduced avoidance rates during acquisition and maintenance for transfer animals and during maintenance for aversive-only animals. These tasks reveal important nuances on the effect of stress on goal-directed behavior and further highlight sexually divergent effects on appetitive versus aversive motivation. Furthermore, these data underscore that systems are temporally impacted by chronic stress in a sexually divergent pattern.