Passive Performance Research Articles

Activation of androgen receptors alters hippocampal synaptic plasticity and memory retention through modulation of L-type calcium channels

AimsIt has been revealed that membrane androgen receptor activation modulates avoidance memory and synaptic plasticity. In a previous study, we showed that Calcineurin, a calcium dependent phosphatase, could be a potential mediator of these AR effects. Also, it is reported that AR activation leads to L-type calcium channel activation. The aim of the current study is to test whether L-type calcium channels are downstream of AR and whether this signal pathway mediates the impairment effect of androgenic steroids on passive avoidance memory and synaptic plasticity. Materials and methodsWe measured the effect of Nandrolone Decanoate (AR agonist), AR antagonist (Nilutamide) plus ND or L-type calcium channel inhibitor (Nifedipine) plus ND on passive avoidance performance of adolescent male rats. For extracellular field potential recordings hippocampal slices were perfused with ND, Nilutamide-ND or Nifedipine-ND. Key findingsOur results clarified that AR activation by ND could impair avoidance behavior as step through latency decreased in ND-treated group while application of both Nilutamide and Nifedipine reestablished normal avoidance behavior. Also, LTP induction in the CA1 area of hippocampus was diminished by ND perfusion and both AR antagonist and L-type calcium channel inhibitor application lead to normal LTP. These findings support our hypothesis that activation of L-type calcium channels are involved in ARs mechanism effects on both avoidance behavior and hippocampal synaptic plasticity. SignificanceUnderstanding the biological effects of AR agonists on cognitive processes and its cellular mechanism may be a new/supplementary way to treating fear-related disorders.

Experimental Evaluation of the Effects of Passive Phase Change Material Walls on the Building Demand Response for Smart Grid Applications

Central air-conditioning systems play a significant role in the demand response (DR) strategies of buildings due to their high energy consumption and flexible energy use. Previous simulation-based studies have shown that the use of phase change materials (PCM) in building envelopes can substantially increase cold storage capacity, which is a key measure for improving the DR performance of buildings. In this study, we experimentally investigated the effect of passive PCM walls on DR performance and conducted quantitative experiments on factors affecting the precooling performance of PCM walls. During DR events, compared to Ordinary walls without a precooling and DR stage, passive PCM walls reduced room cooling loads by 75.05%, electricity consumption by 49.57%, and peak electricity consumption by 31.06%. Additionally, in the precooling period, the impact of the room precooling temperature on passive PCM precooling performance was experimentally studied. When the room precooling temperature was reduced gradually from 21.14 °C to 18.24 °C, the precooling period could be significantly shortened by between 14.58 and 40.43%, and the room cooling load firstly increased and then decreased, during which the cooling load reduction was up to 13.87%.

Scaled validation test for high prandtl number fluid mixed convection between parallel plates

The Kairos Power fluoride salt-cooled high temperature reactor (KP-FHR) passive decay heat removal system performance strongly depends on heat transfer characteristics in the reactor vessel’s down comer region. This region is an annular gap where the salt coolant flows downward between the core barrel and reactor vessel before entering the core region at the bottom of the vessel. Kairos Power’s principal safety analysis code, KP-SAM, extrapolates from existing heat transfer correlations for this geometry and applicable flow configurations. Main flow regimes of interest for safety analysis of the KP-FHR, when the system transitions from forced to natural circulation in the vessel upon loss of forced cooling, are the laminar and transition regimes. These regimes are not very well characterized in the literature, so in order to validate the inclusion of appropriate correlations in KP-SAM, scaled separate effects tests are conducted using a test facility that matches the Reynolds, Rayleigh and Prandtl numbers between the prototypical reactor coolant, Flibe, and a surrogate fluid, Therminol VP-1. The specific boundary conditions investigated are both symmetric heating and asymmetric heating. The data generated from this test serves to develop a validated heat transfer correlation for the laminar and transition regimes for implementation in KP-SAM, in support of safety analysis and licensing of the KP-FHR.

Stability with mixed H ∞/passivity performance analysis of fractional-order neutral delayed Markovian jumping neural networks

Abstract A detailed survey of existing works on fractional-order nonlinear systems reveals the fact that practically no results exist on stability or any performance analysis of Markovian jumping fractional-order systems (FOSs) in general. The main reason is the theory of infinitesimal generator used to estimate the derivative of Lyapunov–Krasovskii Functional (LKF) is not well-developed in the fractional domain. This shortage, in theory, is focussed in this manuscript. In this work, we provide a lemma that aids in analyzing the stability of fractional-order delayed systems via integer-order derivative of LKF. Using this lemma, by constructing a new suitable LKF and employing known integral inequalities, linear matrix inequality (LMI)-based sufficient conditions that ensure stability along with H ∞/passive performance of the proposed fractional-order neural networks (FONNs) with Markovian jumping parameters are derived for the first time. Unlike the existing works, the results derived in the present study depend on the fractional order (FO) of the NNs. The importance of such order-dependent criteria is highlighted in numerical examples. Finally, the simulation results are given to show the reliability of the derived conditions.

Effect of temperature on the passive film structure and corrosion performance of CoCrFeMoNi high-entropy alloy

The effect of temperature on the passive film structure and corrosion performance of CoCrFeMoNi HEA was studied. The results indicated that the passive films exhibited a bilayer structure, where Co and Mo were segregated in the outer film, while Cr was enriched in the inner layer. The content of Fe and Mo species in the passive films decreased with rising temperature, leading to the passive film degradation. The CPT of the HEA was 50–60 ℃. The HEA suffered from selective dissolution of FCC phase below 50 ℃ during the potentiodynamic polarization tests, while pitting corrosion occurred above 60 ℃.

Design of memory-based adaptive integral sliding-mode controller for fractional-order T-S fuzzy systems and its applications

This study investigates the passivity analysis of fractional-order Takagi-Sugeno (T-S) fuzzy systems subject to external disturbances and nonlinear perturbations under an adaptive integral sliding mode control (AISMC) methodology. To better accommodate the features of the T-S fuzzy dynamical model, a novel fractional-order memory-based integral-type sliding manifold function is defined, which is different from the existing sliding manifold function. With the help of Caputo fractional-order derivative properties and quadratic Lyapunov functional, some linear matrix inequality (LMI)-based sufficient criteria are derived to ensure the asymptotic stability conditions of resulting sliding mode dynamics with passive performance index. Besides that, an adaptive sliding mode control law is designed for the addressed systems to guarantee the system state variables onto the predefined integral sliding manifold. Finally, the effectiveness of the proposed controller is validated based on derived sufficient conditions with two practical models, such as fractional-order interconnected power systems and fractional-order permanent-magnet synchronous generator (PMSG) model, respectively.

Adaptive Beamforming Approaches to Improve Passive Radar Performance in Sea and Wind Farms' Clutter.

This article presents the problem of passive radar vessel detection in a real coastal scenario in the presence of sea and wind farms’ clutter, which are characterised by high spatial and time variability due to the influence of weather conditions. Deterministic and adaptive beamforming techniques are proposed and evaluated using real data. Key points such as interference localisation and characterisation are tackled in the passive bistatic scenario with omnidirectional illuminators that critically increase the area of potential clutter sources to areas far from the surveillance area. Adaptive beamforming approaches provide significant Signal-to-Interference improvements and important radar coverage improvements. In the presented case study, an aerial target is detected 28 km far from the passive radar receiver, fulfilling highly demanding performance requirements.

Superconducting routing platform for large-scale integration of quantum technologies

To reach large-scale quantum computing, three-dimensional integration of scalable qubit arrays and their control electronics in multi-chip assemblies is promising. Within these assemblies, the use of superconducting interconnections, as routing layers, offers interesting perspectives in terms of (1) thermal management to protect the qubits from control electronics self-heating, (2) passive device performance with significant increase of quality factors and (3) density rise of low and high frequency signals thanks to minimal dispersion. We report on the fabrication, using 200 mm silicon wafer technologies, of a multi-layer routing platform designed for the hybridization of spin qubit and control electronics chips. A routing level couples the qubits and the control circuits through one layer of Al0.995Cu0.005 and superconducting layers of TiN, Nb or NbN, connected between them by W-based vias. Wafer-level parametric tests at 300 K validate the yield of these technologies while low temperature electrical measurements in cryostat are used to extract the superconducting properties of the routing layers. Preliminary low temperature radio-frequency characterizations of superconducting passive elements, embedded in these routing levels, are presented.

Ensemble of long short-term memory recurrent neural network for semi-active control of tuned liquid wall damper

A critical challenge in structural control is the design of controllers capable of rapid adaptation to uncertainties, including changes in local dynamics and unknown parameters. A solution is the use of data-based controllers, but these typically require pre-training and may be computationally expensive to utilize. In this paper, the authors proposed a fast neuro-controller capable of pure online learning. The controller is built using an ensemble of recurrent neural networks (ERNNs) based on long short-term memory (LSTM) cells running in parallel. A multi-rate sampler is used to sequentially construct the individual RNN input vectors using local measurements at sampling rates pre-determined from the structure’s natural frequencies. Each RNN performs an individual estimation with the associated sampling rate, and these estimations are assembled into an attention and a dense layer to produce an estimated control force. Critical advantages of the proposed architecture are (1) rapid online adaptation and processing; (2) capability to adapt to local dynamics and non-stationarities; and (3) pure online learning architecture minimizing reliance on pre-training. First, the performance of the ERNNs control algorithm is validated on an actively controlled single-degree-of-freedom system, and stability of the controller is demonstrated. Second, the ERNNs is simulated on a full-scale 20-story building equipped with a semi-active tuned liquid wall damper (TLWD) system that consisted of distributed semi-active tuned liquid multiple column dampers. The ERNNs controller effectively improved the passive performance of the control strategy and performed similarly to that of a full state-feedback sliding mode controller under multi-hazard scenario. The evolution of attention weights under both the wind and seismic hazards demonstrated that the importance of each RNN follows the importance of the structural frequency responses, showing that the controller was capable of capturing and adapting fast-changing dynamics.

Design and optimization of anti-climber device for light rail transit crash energy management system

The study of a new anti-climber structural concept for a light rail transit crash energy management system is intended to improve passive safety performance that reduces the risk of overriding during a car-to-car collision. The anti-climber design and configurations are optimized to achieve the best crashworthiness performances. Several model variations are created, to which design factors are assigned based on the L16 orthogonal array. The optimum configuration is estimated using Taguchi’s Robust Parameter method. The controlled variables’ influence on the performance is analyzed using the Analysis of Variance method. The results show that the optimum configuration for the system’s crash energy absorption and crashbox deformation performances are toothed ends-Al6061-T6-30 mm-lower offset with 1.5 dB gain and toothed ends-Al6061-T6-20 mm-lower offset with 3.3 dB gain, respectively. The most influential parameter is the anti-climber material (29.79%) for the system’s crash energy absorption performance and teeth thickness (50.26%) for the crashbox deforming performance.

Cooperative beamforming design for double-IRS-assisted MISO communication system

Intelligent reflecting surface (IRS) has arisen as a promising technology to reconfigure the wireless propagation environment cost-effectively. Most of the existing works on IRS focused on the passive beamforming (PB) optimization and performance enhancement without considering the multiple inter-IRS links cooperation that did not reveal the full preponderance of the multi-IRS-assisted reconfigurable communication system. In this work, we investigate a double-IRS-assisted multiple input single output (MISO) downlink communication system with the active beamforming (AB) and the cooperative PB design in the absence of direct link. Taking both the double-reflection links and the single-reflection links into account, the AB at the base station (BS) and the cooperative PB at two IRSs are jointly optimized to maximize the weight sum rate (WSR) under the constraint of the transmit power. To tackle the problem, we propose the double-IRS-assisted fractional programming block coordinate descent (D-FPBCD) method to find the sub-optimal solution with low complexity. We first reconstruct the original issue as a tractable one by the closed-form fractional programming (FP) approach, then, the prox-linear block coordinate descent (BCD) and successive convex approximation (SCA) techniques are used to find the sub-optimal solution. Finally, simulation results demonstrate the effectiveness of the proposed double-IRS-assisted wireless communication scheme.

Finite-time mixed [formula omitted] and passivity analysis for Takagi–Sugeno fuzzy system with time-varying delays and actuator faults

This paper comes up with an novel augmented Lyapunov–Krasovskii functional (LKF) approach to process finite-time passivity-based H∞ non-fragile state feedback control issue of Takagi–Sugeno fuzzy system (TSFS) via taking the effects of both time-varying delays and actuator faults. Designing a non-fragile controller to guarantee that TSFS is finite-time bounded (FTB) and meet finite-time mixed H∞ and passive performance is the focus of this paper. On the basis of the new augmented LKF and improved boundary techniques, sufficient delay-dependent conditions are inferred to acquire the desired results of the TSFS. Furthermore, the derived finite-time stability conditions are derived in terms of linear matrix inequalities (LMIs) and the controller gain matrices are confirmed through solving LMIs. Subsequently, three examples are addressed to certify the applicability and advantage of the put forward methodology.

RESILLIENT LIVING BY OPTIMIZING THE BUILDING FAÇADE IN DESIGNING POST-COVID HOUSING

The living performance in sustainable development outline contributing factors towards efficiency, such as ecological, economic, health, and social integration. The performance of facade design must be emphasised to describe resilient living and access to mitigate the design of post-coronavirus disease (COVID-19) housing. The spread of the pandemic underlines the importance of providing quality of life and wellbeing in the building environment, hence highlighting a crucial need to improve indoor air quality and passive building performance to minimise the transmission of COVID-19 and indoor airborne diseases as a result of poor ventilation. The passive building performance and facade complement the energy demand and reduce heat gain. Currently, passive design and health are emphasised to link the environmental design approach and architecture and highlight the quality-of-life post-pandemic. The study aims to provide important healthy indoor strategies and passive building performance for open-plan home-office design, to investigate the open-plan home design with optimum thermal performance based on the passive indoor environment, and to examine the bioclimatic response and energy efficiency of home-office design during the pandemic. The responsiveness of bioclimatic and modular construction incorporated with the new home-office design aim to save energy through sustainable material. The Integrated Environmental Solutions Virtual Environment (IESVE) computer software was utilised using simulations involving ranges of illuminance levels in daylight and revealed the acceptable levels of between 300 lux to 500 lux for the home office area. The results demonstrated that the optimum range of solar heat gain coefficient (SHGC) of 0.46 and a U-value of 0.04 W/m2 K reduced the indoor temperature by 5 degrees Celsius during peak time and maintained the air-condition at 28 degrees Celsius, which was within thermal comfort level.

Improvement Options of a Social Housing Prototype in Different Climate Zones in Ecuador

Ecuador is a country with several climate zones. The zones’ characteristics are very different; however, there are social housing prototypes used in all the territories. This study constitutes the second part of the analysis of a social housing prototype in four zones (Cfb, Af, Aw, and BSh) in both the current climate situation (2020) and its projection to 2050. Improvement measures from the original dwelling block have been proposed according to the initial diagnosis, considering seven passive performance variants. A total of 56 dynamic simulations have been performed for both the current and 2050 climate scenario. The results have shown that, depending on the climate zone, improvement measures differently influence comfort ranges. In addition, the behaviour of the dwellings on the upper floor is different from those on the ground floor. This study is a starting point to show that prototype solutions of social housing should be adapted with various improvement measures and should be based on specific requirements according to their location to achieve acceptable comfort levels.

Sucker Shapes, Skeletons, and Bioinspiration: How Hard and Soft Tissue Morphology Generates Adhesive Performance in Waterfall Climbing Goby Fishes.

Many teleost fish, such as gobies, have fused their paired pelvic fins into an adhesive disc. Gobies can use their pelvic suckers to generate passive adhesive forces (as in engineered suction cups), and different species exhibit a range of adhesive performance, with some even able to climb waterfalls. Previous studies have documented that, in the Hawaiian Islands, species capable of climbing higher waterfalls produce the highest passive pull-off forces, and species found at higher elevation sites are likely to have more rounded suction discs than those found in the lowest stream segments. Morphology of the pelvic girdle also varies between species, with more robust skeletons in taxa with superior passive adhesion. To investigate what factors impact the passive adhesive performance of waterfall climbing gobies, we tested biomimetic suction cups designed with a range of shapes and embedded bioinspired "skeletons" based on micro-CT scans of goby pelvic girdles. We found that while the presence of an internal skeleton may provide some support against failure, the performance of suction cups may be more strongly affected by their external shape. Nonetheless, factors besides external shape and skeletal morphology may still have a stronger influence on sucker tenacity. Our results suggest that the relationship between suction disc morphology and adhesive performance may be influenced by a variety of physical factors, and live animal performance likely is further complicated by muscle activation and climbing behavior. These results have implications for the evolution of suction disc shape in adhesive fish and for improving the design of biomimetic suction cups.

Inquiry of the Practice of Leadership in Chengguan: A Study Based on the Ethnographic Research of Z City

Chengguan, the Urban Administrative Law Enforcement Bureau, has been criticized for its dismal public image and poor job performance. Based on an ethnographic case study in Z City, we analyzed the type of leadership that results in passive work performance in Chengguan, and we examined whether any leadership style can be used to improve Chengguan's image and performance. We developed a new leadership ontology of CNP (Cognition–Normalization–Performance) on this foundation, and ethnographic research was conducted in three phases: leader's cognition, followers' normalization, and organization performance. Several implications were drawn. Leader selection should be cautious and can be improved by studying the leader's traits and behavior. This is done by investigating candidates' leadership career paths, trait characteristics, motive profiles, and other qualities. It is useful to change leaders by strengthening followers' unity and cohesion by setting up a labor union, youth federation, women's federation, and other groups. A leader should be selected among individuals who have completed leadership training as opposed to appointing one from outside the organization. On the one hand, the superior should help to improve the leadership environment (context), supervise problems in the organization's operation and performance, and track changes over time. On the other hand, the leader can also provide the followers with a flexible and adaptive place of work.

Task and ecologically based assessment of upper-limb passive function before and after botulinum injections in adults with stroke using the Upper-Limb Performance Assessment: French cross-cultural adaptation and feasibility pilot study

Purpose To test feasibility of a French translation and cross-cultural adaptation of the Upper-Limb Performance Assessment (ULPA) for task and ecologically based assessment of individualized passive function of upper-limb (UL) performance in adults treated with botulinum toxin-A. Materials and methods A case series with seven adults with stroke (29–74 years) for spastic hypertonia management with passive use objectives (hygiene or positioning) established through Goal Attainment Scaling (GAS). Scores on ULPA Task Performance Mastery (TPM) were obtained through clinical and home-based performances before and after treatment. Results Time administration per task ranged from 5-10 min. Median (range) ULPA, Task Performance Mastery (ULPA-TPM) scores pre-intervention of 58 mastery (35–71) improved to 75 (58–88). Tau-U demonstrated significant large effect sizes (≥.65) for five participants. Complementary measures demonstrated improvement of passive performance for five participants and improvements in GAS for six participants. Testing indicates excellent intra-rater (ICC = 0.90) and moderate inter-rater (ICC = 0.64) reliability, with SDC of 10.16 and 18.23%, respectively. Conclusions French use of ULPA is a promising standardized, objective and ecologically based assessment of passive performance in adults with stroke. Preliminary findings after TCCA support feasibility for measurement of individualized goals for UL passive use. Future studies may explore other tasks and environments. Implications for rehabilitation ULPA is a performance-based, criterion-referenced and ecological measure of individualized goals based on task-analysis of upper-limb (UL) performance in real-life situations providing an interest for individualized assessment of activity and participation. The measure provides a standardized and quantitative approach, applicable to passive use of UL across environments, promoting ecological validity of assessment. Preliminary data will support clinical interpretation of change before and after botulinum injections of UL passive performance. Access to a transculturally validated French version of ULPA complements standardized assessment of UL impairment, perceived performance and goal attainment.

Event-Triggered Dissipative Tracking Control of Networked Control Systems With Distributed Communication Delay

This article presents the design of an event-trigger-based networked robust dissipative tracking control systems. An event-triggered mechanism (ETM) is proposed by introducing the probability density distribution of communication delay. Thus, it can yield less conservative results. The tracking error system is transferred by a distributed communication delay system wherein the delay probability density is viewed as the kernel of the distributed delay. The threshold of the proposed ETM is designed as a dynamic parameter to adapt the transmission of the control signal. By applying the Lyapunov method, sufficient conditions are achieved to ensure the stability of the tracking error system with strictly dissipative performance, which includes <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_{\infty }$</tex-math></inline-formula> performance and passive performance. Based on the dissipativity analysis condition, a co-design method with both tracking control and the ETM is derived in a united framework. Experiments on networked dc motor tracking system are provided to show the effectiveness of the presented method.

Study on Decoupling Control Strategy of Redundant Parallel Hybrid Vibration Isolation Platform

Background: The vibration isolation platform (VIP) can greatly reduce the risk of damage to dynamic equipment caused by external vibration interference and provide the most stable and reliable working environment for dynamic equipment. Objective: Aiming at the problems of small vibration isolation dimension, low bearing capacity, serious motion coupling, and narrow vibration isolation bandwidth in the field of vibration isolation of dynamic load equipment, a hydraulic redundant six degrees of freedom parallel vibration isolation platform (PVIP) with active and passive composite vibration isolation support is proposed. Methods: The dynamic coupling model of active and passive hybrid vibration isolation (APHVI) of redundant PVIP is established, and the matrix diagonal decoupling control strategy and fuzzy PI control theory are combined. Analysis of passive vibration isolation performance and APHVI performance of VIP is done. Results: The simulation results show that the effect of APHVI based on fuzzy PI decoupling control is better than that of passive vibration isolation and matrix diagonal decoupling control. Conclusion: Fuzzy PI control can effectively attenuate more than 98 % of the disturbance, significantly improve the vibration isolation performance and decoupling effect of the platform, and expand the effective vibration isolation bandwidth.

Composite event-triggered disturbance-observer-based control and passive control for semi-Markovian jump nonlinear systems with actuator saturation

In this paper, the composite control problem of continuous time semi-Markovian jump system with actuator saturation, multiple disturbances and unknown nonlinearity is investigated. A stochastic stability condition and a lower bound of the time between two consecutive events are derived to avoid Zeno behaviour, based on the combination of disturbance-observer-based control and event-triggered control. In addition, the passive control of the system based on the disturbance observer is studied. Finally, numerical simulation proves that the designed composite controller can effectively save communication resources, and can maintain the system to meet the passive performance indicators of the obtained closed-loop system under the influence of multiple disturbances and actuator saturation.