Real Switches Research Articles

Faster bi-stable visual switching in psychosis

Bi-stable stimuli evoke two distinct perceptual interpretations that alternate and compete for dominance. Bi-stable perception is thought to be driven at least in part by mutual suppression between distinct neural populations that represent each percept. Abnormal visual perception has been observed among people with psychotic psychopathology (PwPP), and there is evidence to suggest that these visual deficits may depend on impaired neural suppression in the visual cortex. However, it is not yet clear whether bi-stable visual perception is abnormal among PwPP. Here, we examined bi-stable perception in a visual structure-from-motion task using a rotating cylinder illusion in a group of 65 PwPP, 44 first-degree biological relatives, and 43 healthy controls. Data from a ‘real switch’ task, in which physical depth cues signaled real switches in rotation direction were used to exclude individuals who did not show adequate task performance. In addition, we measured concentrations of neurochemicals, including glutamate, glutamine, and γ-amino butyric acid (GABA), involved in excitatory and inhibitory neurotransmission. These neurochemicals were measured non-invasively in the visual cortex using 7 tesla MR spectroscopy. We found that PwPP and their relatives showed faster bi-stable switch rates than healthy controls. Faster switch rates also correlated with significantly higher psychiatric symptom levels, specifically disorganization, across all participants. However, we did not observe any significant relationships across individuals between neurochemical concentrations and SFM switch rates. Our results are consistent with a reduction in suppressive neural processes during structure-from-motion perception in PwPP, and suggest that genetic liability for psychosis is associated with disrupted bi-stable perception.

The rapid synthesis of 1,10-phenanthroline-5,6-diimine (Phendiimine) and its fascinating photo-stimulated behavior

Here, for the first time, we report synthesis of 1,10-phenanthroline-5,6-diimine (Phendiimine) based on an acid catalysed SN2 reaction of 1,10-phenanthroline-5,6-dione and 2-picolylamine in EtOH as a solvent. The synthesized Phendiimine molecule showed excellent photo-sensitivity against visible light, together with photoluminescence in both water and ethanol and also, it showed electrochemical activity with Fe electrode in ethanol and H2SO4 solution. Tauc plot also showed Phendiimine is a direct band-gap semiconductor. The hot-point probe test also showed that it is a n-type semiconductor. The UV–vis. absorption maximum shift in two solvents (water and ethanol) demonstrates the solvatochromism behavior of the molecule. The practical significance of this work and its guiding implication for future related research can be outlined as follows. Based on the results obtained, it appears that the Phendiimine molecule could revolutionize the medical field, potentially in the design of artificial eyes, increasing the yield of photovoltaic cells through enhanced heat transfer, improving computers and industrial photo-cooling systems, serving as photo-controller in place of piezoelectric devices, functioning as electronic opt couplers, controlling remote lasers, changing convection in photothermal heaters, designing miniaturized real photo-stimulated motors, creating photo or thermal switches through spin crossover complexes, developing electronic light-dependent resistance (LDR) devices, constructing X-ray and gamma-ray detectors, designing intelligent clothing, creating photo dynamic tumour therapy (PDT) complexes, singlet fission materials in solar cells and more.

Design of dispersion‐reconfigurable phaser using stepped‐impedance line

AbstractThis paper proposes a dispersion‐reconfigurable reflection‐type phaser based on the stepped‐impedance microstrip line structure. By configuring “ON” and “OFF” states of switches, the proposed phaser exhibits positive‐slope, negative‐slope, and zero‐slope linearly dispersive group delay responses. For proof‐of‐concept demonstration, we use line connection/disconnection to mimic the ON/OFF states of real switches. Three prototypes are hence fabricated to represent the three different states. The experimental results agree well with the expected responses, which finally validate the proposed concept.

Faculty network system implementation using cisco packet tracer

In this study, the faculty network system was designed using the Cisco Packet Tracer program without using any physical components. The aim was to simulate the network structure of the faculty and show the engineering faculty on the campus map, and to enable communication between the computers inside the faculty by configuring similar devices to real routers, switches, and servers. The management of the IP configuration of the devices in the network, and the configuration of the router, switch, and server used in the network (DNS, DHCP, FTP, HTTP, and MAIL) were carried out in the Cisco Packet Tracer environment, creating a simulated network system that can be applied in a real system.

Quantum Networks for Resilient Power Grids: Theory and Simulated Evaluation

Quantum networks are considered to be the future of secure communication in the coming quantum era. However, significant efforts are lacking on developing practical quantum networks for power grids. This paper establishes a quantum network-based power grid (QNetGrid) framework and develops a real-time, reliable, flexible, programmable, and cost-effective QNetGrid software testbed containing repeater-based quantum communication, quantum routing, real software-defined networking (SDN) switches, and real-time networked microgrids (NMs) operations. It makes the following contributions: 1) a repeater and routing based quantum network simulator (QNSim) is developed, 2) repeaters with and without quantum memories are respectively simulated in QNSim, 3) different routing scenarios in QNetGrid are investigated, 4) a real-time QNetGrid software testbed is built in RTDS incorporating QNSim and real SDN switches, and 5) various test cases are designed, and experimental results produced with the QNetGrid testbed provide valuable insights for building quantum networks in power grids.

Simulation and analysis models of hybrid software­configured devices

The analysis of the algorithm, based on which the simulation and analytical model of the hybrid software-configurable device is automatically synthesized, was carried out. The solution for modeling OpenFlow equipment was also considered, and an original OpenFlow switch model was developed, which is distinguished by the ability to manage delays based on the results of its mathematical model. The operation scheme of a hybrid switch that supports both traditional switching and OpenFlow switching has been developed. This scheme allows solving complex tasks in the physical infrastructure of virtualized networks. A module has been developed to create a realistic delay and limit the capacity and performance of the hybrid switch model, which can work according to the data obtained as a result of the experimental study. Additional traffic processing schemes have been developed for a more detailed implementation of the hybrid software-configurable equipment model. The basic model of the switch presented in the INET OMNeT++ framework is considered. The switch is represented by a set of modules interacting through the OMNeT transmission system. The most detailed modules of Ethernet interfaces are implemented, in particular, there are implementations of the input queue of the Tail-Drop type, output queues of the FIFO, RED, WRED, PQ, CBFQ types, as well as the implementation of the transmission delay on the line. The virtualization technology of network functions, which is built on the basis of software-configured networks, has been studied, and the most popular Linux-based solutions are used as a software-controlled Open vSwitch switch. The considered methods of forming a model of such a switch. Open vSwitch is architecturally different from both classical and OpenFlow real switches, as there are no dedicated packet refactoring units (except for network cards with hardware header processing and FPGAs), dedicated memory and processors for switching, Open vSwitch uses a kernel module (or module DPDK for direct transmission without the participation of the kernel) to transmit packets based on information from the OVSDB database or OpenFlow tables.

Characteristic Modes-Inspired Polarization Twisting Metasurface Element for 1-bit Folded Reflectarray

A 1-bit folded reflectarray (FRA) based on characteristic modes-inspired polarization twisting metasurface element is proposed. The element is inspired by a 2×2 patch-based metasurface where a corner patch is removed and a pair of the patch is connected to break the symmetry for polarization twist and reduce the number of switches with the assistance of the characteristic mode analysis. On this basis, only two switches are required in each element for 1-bit phase encoding. To verify the proposed metasurface element, two 1-bit FRA in the Ka-band with beam directions of 0° and 60° are designed and fabricated where the metal stubs/open circuits are employed instead of real switches. The measured peak gains reach 27.4 dBi at 30 GHz with an aperture efficiency of 21.2% and a 3 dB bandwidth of 16.2%. This FRA exhibits good beam scanning characteristics with high gain and wide fractional bandwidth, which shows great potential in the application of low-cost electronically beam-steerable antennas.

Enabling Resilient Quantum-Secured Microgrids Through Software-Defined Networking

Quantum key distribution (QKD) has been considered a potent and mature approach to secure communication in the quantum era. However, there exist resilience gaps that hinder the practical usefulness of QKD. This paper improves the resilience of a QKD-based microgrid by leveraging software-defined networking (SDN). Specifically, the following contributions have been made: 1) a novel QKD- and SDN-based communication framework is devised for microgrids; 2) an enhanced QKD simulator (QKDS+) is developed, which can simulate both the number of generated keys and the amount of classical data required, providing a more accurate QKD study in microgrids; 3) an SDN-based resilience enhancement strategy, which incorporates three practical SDN applications, is developed to improve the system's resilience; and 4) a QKD- and SDN-enabled cyber-physical microgrid prototype is built in an RTDS environment using real whitebox SDN switches. Extensive case studies validate the effectiveness and excellent performance of SDN to improve the resilience of QKD-based microgrids in various situations.

What changes in prescription patterns of antiemetic medications in pregnant women in France?

In France, few data are available on the prescription patterns of antiemetic medications in pregnant women. The purpose of this study was to describe antiemetic medication prescriptions and trends over time. Can we observe significantchanges in pregnant woman prescriptions in recent years? We conducted a drug utilization study among pregnant women using data from the EFEMERIS database, including 135574 pregnant women who had a pregnancy outcome between 2004 and 2017 in Haute-Garonne (France). During the study period, 40028 women (29.5%) received at least one antiemetic prescription during pregnancy. Metoclopramide (56.6%), domperidone (34.9%), and metopimazine (28.5%) were the most commonly prescribed antiemetics, whatever the trimester of pregnancy. Prescriptions of ondansetron only concerned 53 women (0.1%). The prevalence of women who received at least one prescription for an antiemetic decreased from 32.5% in 2010 to 21.6% in 2017. This decline mainly concerned domperidone prescriptions (from 13.1% in 2010 to 1.2% in 2017). Metoclopramide prescriptions also decreased slightly (18.3% in 2010 and 14.0% in 2017). Metopimazine prescriptions increased lowly (8.0% in 2010 and 9.0% in 2017). This study showed a decrease of antiemetic prescriptions between 2010 and 2017, linked to the sharp decrease in domperidone use from 2011, probably related to warnings about the risk of cardiovascular adverse effects following exposure to domperidone. We could not observe real switches to other antiemetic medications. No switches to ondansetron could be noted either, with only rare exposure during pregnancy, contrary to other countries, like the United States.

Frequency reconfigurable antenna for cognitive radios with sequential UWB mode of perception and multiband mode of operation

AbstractIn this work, an UWB/narrow band reconfigurable elliptical-shaped monopole antenna for cognitive radio applications with sequential perception and operation modes is presented. The proposed approach consists in integrating a reconfigurable filter, in an UWB antenna ground plan, by the mean of four horizontal slots and integrated switches that allow inserting/removing/varying zeros and poles in the frequency response. By acting on the slot lengths in order to alter their resonance frequencies, the different switch configurations allow the antenna to switch between an UWB mode that could be used for the perception (sensing) and different narrowband modes, mono-band and dual-band, that could be used for the operation at 2.4 or/and 3.5 GHz. To validate the concept, an experimental prototype has been fabricated and a good agreement between the simulated and the measured S-parameters has been obtained. While the presented work uses the presence/absence of a perfect conductive strip (PEC) to model real switch operation, it is believed that the obtained results conjugated with previous work using real switches on a very similar structure allows validating approach.

Simulation of reversely switched dynistors in modes with a lowered primary-ignition threshold

A new method for triggering reversely switched dynistors (RSDs) into submicrosecond modes with high current-rise rates being switched at a substantially lower primary ignition threshold is proposed and studied numerically in detail by computer simulation methods. The numerical problem considers all the relevant physical laws for the spatially distributed and discrete elements of RSD switching unit, including the nonlocal isochronous interaction between the working regions of power RSDs or the photodiode control switches and external-circuit components. The simulation results confirm the possibility of reaching, in actual practice for RSDs, current-rise rates up to dJ/dt = 3 × 1010 A cm–2 s–1 in circuits based on lowpower semiconductor control switches at primary ignition levels relative to a reversely injected charge, which has a density as low as 1–2 μC/cm2. These parameters have been considered previously as only a theoretical limit, unachievable in the submicrosecond range for real thyristor switches.

Bistate Frequency Selective Surfaces Made of Intertwined Slot Arrays

Novel arrangements of active frequency selective surfaces (AFSSs) with integrated voltage control wiring are proposed for bistate (transparency/reflectance) operation at specified frequencies. The AFSSs are comprised of passive arrays of intertwined patterns of slots in a conductor screen and an active dipole array with p-i-n diodes placed on either the same or opposite sides of a thin dielectric substrate. Simulation and measurement results show that such AFSSs exhibit good isolation (~15 dB) between the translucency and reflection states at normal incidence that slightly decreases at oblique incidence. The proposed AFSSs maintain the high angular and polarization stability over broad fractional bandwidths inherent to the constituent periodic arrays of intertwined conductor patterns with substantially subwavelength unit cells. The merits of these AFSS arrangements also include resilience to parasitic effects of real switches, whose insertion loss in the ON state only enhances the AFSS ON/OFF isolation. Such AFSSs are essential elements for reconfiguring and controlling the electromagnetic architecture of buildings.

Reconfigurable and Tunable Filtenna for Cognitive LTE Femtocell Base Stations

A single-port uniplanar antenna with a built-in tunable filter is presented for operation in multiple LTE bands for cognitive femtocell applications. The antenna is based on a monopole microstrip patch fed by coplanar waveguide. The frequency reconfigurability is achieved by using two PIN diodes to couple or decouple a ring slot resonator filter from the antenna feed line. By switching the PIN diodes, the proposed design can operate in either wideband or narrowband modes. When the antenna operates in the narrowband state, two varactor diodes are used to continuously tune the narrowband frequency from 2.55 to 3.2 GHz, while the wideband state is obtained over the 1.35–6.2 GHz band. The diodes and their biasing networks have nearly no severe effect on the antenna characteristics. Prototypes of the proposed structure using ideal and real switches, with and without varactors, are fabricated and tested. Measured and simulated results are in good agreement, thus verifying the good performance of the proposed design. The obtained results show that the proposed antenna is very suitable for cognitive radio applications, in which the wideband mode is used for spectrum sensing and the narrowband mode for transmission at different frequency bands.

Long-term RF Burn-in Effects on Dielectric Charging of MEMS Capacitive Switches

This paper experimentally quantified the long-term effects of RF burn-in, in terms of burn-in and recovery times, and found the effects to be semipermanent. Specifically, most of the benefit could be realized after approximately 20 min of RF burn-in, which would then last for several months. Additionally, since similar effects were observed on both real and faux switches, the effects appeared to be of electrical rather than mechanical nature. These encouraging results should facilitate the application of the switches in RF systems, where high RF power could be periodically applied to rejuvenate the switches.

A model to obtain optimal designs of railway overhead knuckle junctions using simulation

The design of overhead knuckle junctions in railway electrification is a crucial and complex problem. Non-optimal overhead knuckle junction designs cause limitations in train speed and, most important, malfunctions and breakages. Most railway companies have regulations for the design of overhead knuckle junctions. Those regulations have been defined by the experience, but, as far as we know, there are no computerized software tools to help with the task of designing and testing optimal solutions for overhead knuckle junctions. In this paper we present a simulator that allows to look for optimal configurations of overhead knuckle junctions. The simulator starts from a model based on the description of the problem that includes all the significant elements that may affect the design process, in order to find an optimal solution in terms of reliability and safety. The obtained design will be the more reliable to face failures, such as excessive wire and pantograph wears, wrong geometry configurations of the catenary, or electricity supply notches. The simulator also allows to evaluate current designs, so as to prove their possible flaws. This paper describes the simulation algorithm developed, the input data needed to define the experiments, and the achieved results. As the simulator requires heavy computational resources, high productivity parallel issues have been included in the implementation to exploit current multi-core processors. The validation and performance evaluations were made in the paper through the simulation of overhead knuckle junction designs over real switches. Their analysis will show the feasibility and applicability of our simulator.

A systematic reliability investigation of the dielectric charging process in electrostatically actuated MEMS based on Kelvin probe force microscopy

This paper presents a comprehensive investigation for the dielectric charging problem in electrostatically actuated microelectromechanical system (MEMS) devices. The approach is based on Kelvin probe force microscopy (KPFM) and targets, in this specific paper, thin PECVD silicon nitride films for electrostatic capacitive RF MEMS switches. KPFM has been employed in order to mimic the potential induced at the dielectric surface due to charge injection through asperities. The effect of dielectric thickness has been investigated through depositing SiNx films with different thicknesses. Then, in order to simulate the different scenarios of dielectric charging in real MEMS switches, SiNx films have been deposited over thermally grown oxide, evaporated gold and electroplated gold layers. Also, the effect of the deposition conditions has been investigated through depositing dielectric films using low and high frequency PECVD methods. The investigation reveals that thin dielectric films have larger relaxation times compared to thick ones when the same injection bias is applied, independently of the substrate nature. For the same SiNx film thickness, the decay time constant is found to be smaller in dielectric films deposited over metallic layers compared to the ones deposited over silicon substrates. Finally, the material stoichiometry is found to affect the surface potential distribution as well as the relaxation time constant.

Energy Surface Analysis and Critical Points of a Symmetric Synthetic Antiferromagnet

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, a new method to calculate the critical points (CPs) for a symmetric synthetic antiferromagnet, using the Stoner–Wohlfarth model for each layer is proposed. For given initial conditions, the system has multiple equilibrium states, and consequently, there are multiple energy barriers (EBs), so it is rather difficult to estimate the actual EBs for the real switches. Using the developed method, one can determine all the minimum energy points as well as the saddle points (SPs) based on the solutions of polynomial equations associated to the critical points conditions. These are necessary conditions to estimate the EB. Defining the EB as the difference between the lowest SP and the highest energy minimum for an applied field, one obtains for the lowest values of the EB the well-known critical curves. The plot of the EBs in the field planes is compared with the graphs of the critical curves and the results are discussed. </para>

A USB kit for digital I/O applications in a digital electronics lab designed by using PIC16C765 microcontroller

AbstractIn this article, a USB Kit is designed by using Microchip's PIC16C765 microcontroller that has a low‐speed USB serial interface engine. It is used to communicate with and/or through USB port for digital I/O applications in a Digital Electronics Lab. In this education kit, two groups of keys (switches) and a group of LED are used to realize the experiments about logic gate applications included in Electronics and Computer Education Department's curriculum of Marmara University and also included in other faculties' curriculums related to the engineering science all around the world. In designed board, one of the key groups is 8‐bit software‐controlled by using simulator interface and the other is 8‐bit user‐controlled by using real switches existing on the board. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 131–138, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20172

LLG Simulation of MRAM Switching Trajectories

The simplest method for estimating switching rates, transition state theory (TST), badly overestimates the switching rate for common materials with low Landau-Lifshitz damping. By classifying and counting simulated switching trajectories, we show why this occurs: there are orbits that swing back and forth between the stable potential wells (and are counted as multiple switches by the TST) which are not real switches. We suggest methods for correcting the TST rate for this phenomenon, to correctly estimate the switching rate for MRAM and spin-torque systems

Modelling Electromechanical Systems with Electrical Switching Components Using the Linear Complementarity Problem

In this paper, a method for modelling electromechanical systems (EMS) with variable structure in the electrical subsystem is proposed. This structural variability may result from real switches (e.g. relay) or from components with switching characteristics (e.g. diode in first approximation). The aim of the work is to provide a method to model EMS with variable structure in both domains using a unified mathematical theory. For this purpose, the usage of the linear complementarity problem (LCP) for modelling electrical systems containing components with switching characteristics is shown. Starting point of the complete approach is a method for modelling EMS based on the Lagrange formalism. A unified mathematical theory is used to represent such systems taking into account all interactions between the physically heterogeneous substructures. Applying the LCP, it is possible to include switching components into this theory and, this way, to extend the class of EMS which can be captured.