Actual Switches Research Articles

Design and Experimental Verification of Electric Vehicle Battery Charger Using Kelvin-Connected Discrete MOSFETs and IGBTs for Energy Efficiency Improvement

This research investigates the advantages of Kelvin-connected 4-pin discrete transistors, both MOSFETs and IGBTs, in onboard battery chargers for electric vehicles. The study compares the standard 3-pin and the extended 4-pin packages based on averaged data collected from leading manufacturers. The investigation shows significant potential power loss reduction, thermal operation mitigation, and reduced gate-drive oscillation for the 4-pin package. The benefits have been quantified by analysing the operation of actual switches in an automotive battery charger based on Boost-PFC and DC-DC LLC converters. The converters’ practical design demonstrates a procedure for integrating the Kelvin-connected package into the design methodology. The results have been verified experimentally.

Performance Analysis of Internet of Vehicles Mesh Networks Based on Actual Switch Models

The rapid growth of the automotive industry has exacerbated the conflict between the complex traffic environment, increasing communication demands, and limited resources. Given the imperative to mitigate traffic and network congestion, analyzing the performance of Internet of Vehicles (IoV) mesh networks is of great practical significance. Most studies focus solely on individual performance metrics and influencing factors, and the adopted simulation tools, such as OPNET, cannot achieve the dynamic link generation of IoV mesh networks. To address these problems, a network performance analysis model based on actual switches is proposed. First, a typical IoV mesh network architecture is constructed and abstracted into a mathematical model that describes how the link and topology changes over time. Then, the task generation model and the task forwarding model based on actual switches are proposed to obtain the real traffic distribution of the network. Finally, a scientific network performance indicator system is constructed. Simulation results demonstrate that, with rising task traffic and decreasing node caching capacity, the packet loss rate increases, and the task arrival rate decreases in the network. The proposed model can effectively evaluate the network performance across various traffic states and provide valuable insights for network construction and enhancement.

Circuit Techniques to Suppress Crosstalk Due to Circuit Nonidealities in Zero-Potential-Biasing Method for Resistive Sensor Matrix

Crosstalk between the sensor element to be read and the other sensor elements in the sensor matrix constitutes a critical problem in reading passive matrix resistive sensors. Various zero-potential-biasing readout circuits have been proposed to solve the crosstalk problem, but crosstalk remains due to circuit nonidealities, such as the offset and finite open-loop gain of the amplifiers and the ON-resistance of the switches used in the readout circuit. Therefore, we propose a novel low crosstalk zero-potential-biasing readout circuit that can suppress crosstalk caused by these nonidealities of circuits. The main ideas of the proposed readout circuit to suppress crosstalk are: 1) including the unaddressed sensors and switches into the feedback loop that is formed by the biasing amplifier to remove crosstalk resultant from the finite open-loop gain of the amplifiers and the ON-resistance of the switches and 2) applying the correlated double sampling method to remove crosstalk caused by the offset of the amplifiers. In the measurement of the proposed readout circuit composed of actual commercial amplifiers and switches, the maximum readout error of the proposed readout circuit for an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 resistor matrix is reduced to lpzrptPlus51.82% from the errors of −81.32% and −88.68% of the previous readout circuits selected for comparison.

Detecting Developers’ Task Switches and Types

Developers work on a broad variety of tasks during their workdays and constantly switch between them. While these task switches can be beneficial, they can also incur a high cognitive burden on developers, since they have to continuously remember and rebuild the task context–the artifacts and applications relevant to the task. Researchers have therefore proposed to capture task context more explicitly and use it to provide better task support, such as task switch reduction or task resumption support. Yet, these approaches generally require the developer to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">manually</i> identify task switches. Automatic approaches for predicting task switches have so far been limited in their accuracy, scope, evaluation, and the time discrepancy between predicted and actual task switches. In our work, we examine the use of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">automatically</i> collected computer interaction data for detecting developers’ task switches as well as task types. In two field studies–a 4h observational study and a multi-day study with experience sampling–we collected data from a total of 25 professional developers. Our study results show that we are able to use temporal and semantic features from developers’ computer interaction data to detect task switches and types in the field with high accuracy of 84 percent and 61 percent respectively, and within a short time window of less than 1.6 minutes on average from the actual task switch. We discuss our findings and their practical value for a wide range of applications in real work settings.

Loss of Metabolic Flexibility in the Failing Heart.

To maintain its high energy demand the heart is equipped with a highly complex and efficient enzymatic machinery that orchestrates ATP production using multiple energy substrates, namely fatty acids, carbohydrates (glucose and lactate), ketones and amino acids. The contribution of these individual substrates to ATP production can dramatically change, depending on such variables as substrate availability, hormonal status and energy demand. This “metabolic flexibility” is a remarkable virtue of the heart, which allows utilization of different energy substrates at different rates to maintain contractile function. In heart failure, cardiac function is reduced, which is accompanied by discernible energy metabolism perturbations and impaired metabolic flexibility. While it is generally agreed that overall mitochondrial ATP production is impaired in the failing heart, there is less consensus as to what actual switches in energy substrate preference occur. The failing heart shift toward a greater reliance on glycolysis and ketone body oxidation as a source of energy, with a decrease in the contribution of glucose oxidation to mitochondrial oxidative metabolism. The heart also becomes insulin resistant. However, there is less consensus as to what happens to fatty acid oxidation in heart failure. While it is generally believed that fatty acid oxidation decreases, a number of clinical and experimental studies suggest that fatty acid oxidation is either not changed or is increased in heart failure. Of importance, is that any metabolic shift that does occur has the potential to aggravate cardiac dysfunction and the progression of the heart failure. An increasing body of evidence shows that increasing cardiac ATP production and/or modulating cardiac energy substrate preference positively correlates with heart function and can lead to better outcomes. This includes increasing glucose and ketone oxidation and decreasing fatty acid oxidation. In this review we present the physiology of the energy metabolism pathways in the heart and the changes that occur in these pathways in heart failure. We also look at the interventions which are aimed at manipulating the myocardial metabolic pathways toward more efficient substrate utilization which will eventually improve cardiac performance.

MODELLING THE SWITCHING LINK AND MATHEMATICAL OF ACTUAL TRAFFIC

The paper represents the research results of studying the switches. The model of a switching link has been suggested. The switch has been presented in the form of a Queuing System (QS), the study of dynamic characteristics of switches has been undertaken and the adequacy of the proposed model of a switching link to actual switches has been valued. The maximum error of the modelling is no more than 5%, which indicates the sufficient adequacy of the switching link as related to the evaluation of its probability-time characteristics. The accuracy given is eligible for practical and engineering research works. The self-similar traffic characteristics causing an overload rise when passing through the switching links have been studied by means of simulation modelling. The simulation test conducted of the traffic passing through the switching link showed three characteristics to be significant: Intensity, Fano parameter and Hurst exponent.

Who stays unwillingly in a job? A study based on a representative random sample of employees

This article examines the antecedents of intentions to quit, job search and actual job switches during a follow-up period. The authors use a representative random sample of all Finnish employees. The data set both contains information on intentions to quit and on-the-job search from a cross-sectional survey and records employees’ actual job switches from longitudinal register data that can be linked to the survey. The authors study the contribution of adverse working conditions (harms, hazards, uncertainty and physically and mentally heavy work), work organization (promotion prospects, discrimination and supervisor support) and ease-of-movement factors (mental health, wage level). Adverse working conditions, poor promotion prospects, discrimination and mental health symptoms are positively related to unwillingly staying in a job, since these variables increase the probability of turnover intentions or job search but not actual job switches. These variables include both factors that push employees to job search and factors that make them less employable.

Simulation Model of Space Vector Modulated Control Matrix Converter-fed Induction Motor

Matrix converters as induction motor drivers have received considerable attention in recent years because of its good alternative to Voltage Source Inverter Pulse Width Modulation (VSI-PWM) converters. This study focus on developing a mathematical model for a Space Vector Modulated (SVM) direct controlled matrix converter. The mathematical expressions relating the input and output of the three phase matrix converter are implemented by using MATLAB/SIMULINK. The duty cycles of the switches are modeled using space vector modulation for 0.5 and 0.866 voltage transfer ratios. Simulations of the matrix converter loaded by passive RL load and active induction motor are performed. A unique feature of the proposed model is that it requires very less computation time and less memory compared to the power circuit realized by using actual switches. In addition, it offers better spectral performances, full control of the input power factor, fully utilization of input voltages, improve modulation performance and output voltage close to sinusoidal.

Bonding of a Carbon Nanotube Film to a Au Film at Low Temperature and Contact Resistance of the Film under Micronewton Loads

A process for bonding a carbon nanotube (CNT) film to a Au film at low temperature was developed with a view to using the CNT films as electrical contact materials in radio-frequency microelectromechanical systems (RF MEMS) switches. First, a CNT film was synthesized on a silicon substrate at 750 °C and subsequently coated with Au at room temperature. Finally, the Au-coated CNT film was bonded at 100 °C to a Au film, which was then deposited on a silicon substrate to act as a transmission line. An apparatus was developed to measure contact resistances and forces under contact conditions mimicking those that will be encountered in actual RF MEMS switches, such as micronewton loads and square-micrometer contact areas. Contact resistance and force of the bonded CNT film sample were simultaneously measured as a function of displacement between the sample and an electrode Au tip and compared with those for a Au film and Au-coated CNT film. The bonded CNT film sample had no adhesion force, but higher contact resistance than the other samples.

Impedance Analysis of Heat Treated Polyethylene Oxide Polymeric Material for a Neural Storage Application

Problem statement: From the early days of, researchers have developed electronic models of neurons designed to emulate neural behavior with electrical signals that mimic in some ways the measured potentials of biological neurons. Research ers interested in fabricating artificial neurons ha ve long sought a simple and techniques to produce devi ces that efficiently store synaptic weights, which is behind holding a particular state in relation to co nductance parameters. As Engineers become closer to realizing accurate hardware models of neurons, the need for a simple analog memory device grows correspondingly. To determine the storage character istics of polyethylene oxide based polymer as the base material for high charge storage analogue neur al switch. Approach: Various devices prepared under controlled conditions. Each device tested for its impedance characteristics as a function of bot h frequency and temperature. Mathematical model developed to account for the obtained characteristics. Results: The heat treated devices showed stability, repeatab ility and ability to store enough charge for long time periods. Impedance analysis proved a simi lar response to the actual neural switches. Conclusion: The symmetrical behavior for such devices opened a wide application area for the manufacturing of low and high frequency analogue devices for intelligent system applications.

Job Disamenities, Job Satisfaction, Quit Intentions, and Actual Separations: Putting the Pieces Together

We analyze the role of adverse working conditions in the determination of employees’ quit behavior. Our data contain both detailed information on perceived job disamenities, job satisfaction, and quit intentions from a cross‐section survey, and information on employees’ actual job switches from longitudinal register data that can be linked to the survey. We show that job dissatisfaction that arises in adverse working conditions is related to job search and this in turn is related to actual job switches.

Job Disamenities, Job Satisfaction, Quit Intentions, and Actual Separations: Putting the Pieces Together

We analyze the potential role of adverse working conditions at the workplace in the determination of employees' quit behavior. Our data contain both detailed information on perceived job disamenities, job satisfaction, and quit intentions from a cross-section survey and information on employees' actual job switches from longitudinal register data that can be linked to the survey. Reduced-form models show that employees facing adverse working conditions tend to have greater intentions to switch jobs and search for new matches more frequently. Multivariate probit models point out that job dissatisfaction that arises in adverse working conditions is related to job search and this in turn is related to actual job switches.

Failure Mechanisms of Capacitive MEMS RF Switch Contacts

Microelectromechanical systems (MEMS) radio frequency (RF) switches hold great promise in a myriad of commercial, aerospace, and military applications. In particular, capacitive type switches with metal-to-dielectric contacts (typically Au- on-silicon nitride) are suitable for high frequency (≥10 GHz) applications. However, there is little fundamental understanding of the factors determining the performance and reliability of these devices. To address this void in understanding, we conducted fundamental studies of Au-on-Si3N4 contacts at various bias voltages using a micro/nanoadhesion apparatus as a switch simulator. The experiments were conducted in air at 45% relative humidity. The switch simulator allows us to measure fundamental parameters such as contact force and adhesion, which cannot be directly measured with actual MEMS switches. Adhesion was found to be the primary failure mechanism. Both a mechanical and electrical effect contributed to high adhesion. The mechanical effect is adhesion growth with cycling due to surface smoothening, which allows increased van der Waals interaction. The electrical effect on adhesion is due to electrostatic force associated with excess charge trapped in the dielectric, and was only observed at 40 V bias and above. The two effects are additive, but the electrical effect was not present until surfaces were worn smooth by cycling. Surface smoothening increases the electric field in the dielectric, which leads to trapped charge and higher adhesion. Excessive adhesion can explain decreased lifetime at high bias voltage previously reported with actual capacitive MEMS switches. Aging of open contacts in air was found to reduce adhesion. Surface analysis data show the presence and growth (in air) of an adventitious film containing carbon and oxygen. The adventitious film is responsible for aging related adhesion reduction by increasing surface separation and/or reducing surface energy. No junction growth and force relaxation with time were observed in capacitive switch contacts, as was previously observed with Au–Au contacts at low current in direct current MEMS switches.

Thermal modeling of electrical contacts in switches and relays

A thermal modeling procedure has been developed to calculate the temperature distribution of components in complex three-dimensional (3-D) switches and relays. The methods developed for dissecting the components, treating of thermal interaction among the components, and calculating of interface thermal resistance are reported. In particular, the knowledge of electrical "a-spot" is used to estimate solid-solid contact area and void area. The void areas do not contribute to electrical conductivity but do contribute to thermal conductivity. The method is used to more accurately estimate the interface thermal resistance which is very important in any thermal analysis program. Actual switches and relays were modeled using finite difference thermal analysis, and the results matched well with measured temperatures.

Male sticklebacks can distinguish between familiar rivals on the basis of visual cues alone

Abstract. One-way mirrors were used to determine whether male three-spined sticklebacks, Gasterosteus aculeatus, could use visual cues to distinguish between pairs of neighbours that had similar social and physical attributes. Neighbours were enclosed in identical tanks that had no physical landmarks. The tanks had opaque side-walls and one-way mirrors (reflecting inward) placed along end-walls; thus, neighbours could not see outside of their tanks. Neighbour tanks were positioned at the ends of a test tank so that a resident could view both neighbours. Tanks were left undisturbed until residents completed a nest (ca 4-6 days). If neighbours were then switched from one end of a residents' territory to the other, residents charged toward and bit at the neighbours more often than they did following a 'mock' switch (i.e. neighbours were moved but then returned to their original position); following actual switches, males also devoted less effort to nest maintenance. Furthermore, the amount of effort devoted to defending a given side of the tank depended on which neighbour was there. The neighbours' surroundings did not change after switches, nor did their behaviour. Thus, male sticklebacks can distinguish between familiar rivals using visual cues alone. The ability developed in 4-6 days (i.e. the time required to build nests) and did not require physical interaction with the neighbours.