Unitary Input Research Articles

Adaptive composite dynamic surface neural control for nonlinear fractional-order systems subject to delayed input

In the article, the adaptive composite dynamic surface neural controller design problem for nonlinear fractional-order systems (NFOSs) subject to delayed input is discussed. A fractional-order auxiliary system is first designed to solve the input-delay problem. By using the developed novel estimation models, the defined prediction errors and the states of error system can decide the weights of radial basis function neural networks (RBFNNs). During the dynamic surface controller design process, the developed fractional-order filters are designed to handle the complexity explosion problem when the classical backstepping control technique is utilized. It is shown that the designed adaptive composite neural controller ensures that all the system state variables are bounded and the tracking error of the considered system finally tends to a small neighborhood of zero. Finally, the results of the simulation explain the feasibility of the developed controller. In addition, the developed controller can also be applied to single input and single output(SISO) nonlinear systems subject to a unitary input function.

A Single-Phase Hybrid Six-Leg AC–DC–AC Multilevel Converter

This article presents a single-phase hybrid six-leg ac-dc-ac multilevel converter. The configuration is composed of a three-leg neutral point clamped converter connected in series with a three-leg two-level converter. The proposed converter provides a sinusoidal input current with unitary input power factor and it feeds the load with a stable ac voltage. The system model, operation principles, and a control strategy are presented and discussed. Additionally, a space-vector puslewidth modulation technique is developed to control the dc-link capacitors, to produce optimal voltage waveforms, and to reduce the switching losses. The converter can generate 9-level and 11-level output voltages when operating with symmetrical and asymmetrical dc-link voltages. Experimental and simulation results are presented to validate the theoretical studies.

Dual output from unitary input for a hybrid coaxial triboelectric nanogenerator inspired by a crank engine

Energy conversion cannot be sufficiently achieved from a single output device having a single input. Energy conversion efficiency and output power of triboelectric nanogenerator (TENG) can be enhanced by increasing the contact area or the number of devices. Especially, combining two or more of the four operational mode (contact-separation, lateral sliding, single electrode, freestanding) of triboelectric nanogenerator would be more efficient to harvest mechanical energy than with singleharvesting mode. In this paper, a hybrid coaxial triboelectric nanogenerator (HC-TENG) can generate electrical output from dual outputs. This HC-TENG consists of a disk-TENG and LS-TENG so that a large current can be harvested from the rotating movement of disk-TENG at a high frequency input and an additional output can be generated from the LS-TENG by adding one axis. The structure of device with one axis was inspired by the structure of crank engine, which can convert linear motion into rotational motion. When applying the structure of HC-TENG to an application, the input-output efficiency was calculated by using the rotational kinetic energy formula with the value of 16.66%. Moreover, the efficiency of HC-TENG was verified by comparing experimental values with theoretical calculations for the presence of the dual outputs. This combination of multiple TENGs can be adopted for enhancing efficiency from every ambient rotational movement in real life.

ASA Based Unitary Input Model for Sequential Processing of Speech Separation

ASA Based Unitary Input Model for Sequential Processing of Speech Separation

Factors affecting the performance of Pantaneiro horses

This study aimed to assess the physical performance of Pantaneiro horses with and without equine infectious anemia (EIA) under functional conditions of cattle management. The horses were subjected to a performance test and split into two groups according to a completely randomized design: animals were chosen from populations testing positive and negative for EIA. Performance was measured as a function of a data envelopment analysis (DEA) model considering four outputs and one unitary input. The output measures were the distance achieved in the performance test, hematocrit as a weighted average over the test duration, respiratory rate as weighted average over the test duration, and the level of lactic acid at the test termination. Weights for the hematocrit and the respiratory rate output variables were determined by means of factor analysis. The performance score was a weighted average of the output variables with the weights defined by the averages of the optimum individual multipliers in the DEA analysis. Contextual variables of interest were age, horse weight, room temperature, and corporal temperature. Only groups and room temperature were statistically significant effects, as indicated by a bootstrap analysis. The performance of group positive for EIA is significantly lower than that of the group negative for EIA and room temperature has a negative effect.

A Model Predictive Power Factor Control Scheme With Active Damping Function for Current Source Rectifiers

A model predictive power factor control (MPPFC) scheme is proposed for high-power medium-voltage (MV) current source rectifiers (CSRs). Facing two major issues on input power factor (PF) and LC resonance, the proposed MPPFC uses a novel line reactive power reference estimator to achieve unitary input PF or maximum achievable input PF for a CSR at various operating states, and involves active damping function into itself to mitigate LC resonance at line side. An online capacitance estimation method is associated with the proposed line reactive power reference estimator to guarantee more accurate input PF control, and a novel damping current calculation method, which avoids the use of band-stop filter, is also designed for active damping purpose. In comparison with traditional linear control, the proposed MPPFC not only realizes input PF regulation, but also achieves better steady-state performance on meeting the grid code requirements. In contrast to traditional model predictive control (MPC) for a CSR, the proposed MPPFC achieve more accurate reactive power control. Moreover, it overcomes the challenge on the realization of active damping based on MPC, which extends the application of MPC into high-power MV CSR. Simulation on a high-power CSR (1 MVA/4160 V/139 A) and experiments on a low-power prototype (5 kVA/208 V/13.9 A) are both conducted to verify the effectiveness of MPPFC.

Unitary synaptic connections among substantia nigra pars reticulata neurons

Neurons in substantia nigra pars reticulata (SNr) are synaptically coupled by local axon collaterals, providing a potential mechanism for local signal processing. Because SNr neurons fire spontaneously, these synapses are constantly active. To investigate their properties, we recorded spontaneous inhibitory postsynaptic currents (sIPSCs) from SNr neurons in brain slices, in which afferents from upstream nuclei are severed, and the cells fire rhythmically. The sIPSC trains contained a mixture of periodic and aperiodic events. Autocorrelation analysis of sIPSC trains showed that a majority of cells had one to four active unitary inputs. The properties of the unitary IPSCs (uIPSCs) were analyzed for cells with one unitary input, using a model of periodic presynaptic firing and stochastic synaptic transmission. The inferred presynaptic firing rates and coefficient of variation of interspike intervals (ISIs) corresponded well with direct measurements of spiking in SNr neurons. Methods were developed to estimate the success probability, amplitude distributions, and kinetics of the uIPSCs, while removing the contribution from aperiodic sIPSCs. The sIPSC amplitudes were not increased upon release from halorhodopsin silencing, suggesting that most synapses were not depressed at the spontaneous firing rate. Gramicidin perforated-patch recordings indicated that the average reversal potential of spontaneous inhibitory postsynaptic potentials was -64 mV. Because of the change in driving force across the ISI, the unitary inputs are predicted to have a larger postsynaptic impact when they arrive late in the ISI. Simulations of network activity suggest that this very sparse inhibitory coupling may act to desynchronize the activity of SNr neurons while having only a small effect on firing rate.

Avaliação de unidades portuárias brasileiras com análise envoltória de dados e o método multicritério ordinal de Copeland

<p>Como o tipo de carga influi diretamente na infraestrutura necessária à sua movimentação, algumas unidades portuárias buscam a especialização ou diversificação das atividades. Este trabalho utiliza a Análise Envoltória de Dados e o método multicritério ordinal de Copeland para avaliar a importância relativa de cada unidade do setor portuário brasileiro para o comércio nacional, dentro do respectivo segmento em que cada uma delas atua, comparando-se ambas as técnicas. Dada a não homogeneidade, as unidades são distribuídas em oito clusters, conforme a natureza da carga que operam. Como tal segregação é imediata, não é usada nenhuma ferramenta matemática para este fim. Em seguida, são aplicadas as duas abordagens supracitadas de apoio à decisão. No primeiro caso, é usado um modelo com input unitário, em que o input representa a própria existência da unidade portuária; além disto, para aumentar o poder de discriminação, utiliza-se o índice de eficiência composto normalizado no lugar do índice padrão. Os resultados indicam que as ordenações Copeland e do índice composto são bastante semelhantes. O presente trabalho também esclarece as diferenças entre os resultados de DEA com input unitário e de métodos multicritérios ordinais, indicando o modelo mais adequado em cada situação.</p>

Design of a Teaching Tool for Stability Analysis of DC-DC Converters

This paper describes the design of a virtual instrument (VI) to analyze stability in control systems implemented in LabVIEW virtual instrumentation software. The VI generates a Routh-Hurwitz array for analyzing system stability based on obtaining the characteristic D (s) equation and is able to identify situations where there is a space or row of zeros within the array. Furthermore, the VI shows the graphical location of the poles and zeros of the transfer function in closed loop, the graphical system response to a unitary step input and peak time, overshoot, settling time and peak value of the step response. Finally a case study on a DC-DC buck type converter operating in continuous and discontinuous conduction is reviewed.

Unitary input DEA model to identify beef cattle production systems typologies

The cow-calf beef production sector in Brazil has a wide variety of operating systems. This suggests the identification and the characterization of homogeneous regions of production, with consequent implementation of actions to achieve its sustainability. In this paper we attempted to measure the performance of 21 livestock modal production systems, in their cow-calf phase. We measured the performance of these systems, considering husbandry and production variables. The proposed approach is based on data envelopment analysis (DEA). We used unitary input DEA model, with apparent input orientation, together with the efficiency measurements generated by the inverted DEA frontier. We identified five modal production systems typologies, using the isoefficiency layers approach. The results showed that the knowledge and the processes management are the most important factors for improving the efficiency of beef cattle production systems.

Vector operation of one-cycle controlled matrix rectifier

Vector operation of one-cycle controlled matrix rectifier A novel vector operated one-cycle control matrix rectifier (OCC-MR) is proposed in this paper. Matrix rectifier (MR) is a generalized buck three-phase AC-DC converter with four-quadrant operation capability. MR can also be the front-stage circuit of AC-DC-AC equivalent structure of MC. One-cycle control (OCC) is a nonlinear control technique, which integrates modulation algorithm and control strategy. By applying OCC to current control loop, the OCC-MR achieves balance only in a switching cycle, and realizes unitary input power factor. Furthermore, vector operation of OCC results in minimum switching losses. In order to make up for the insufficiency of OCC on load disturbance suppression, a PID controller is added onto output voltage control to improve load regulation. The OCC-MR features great simplicity, fast dynamic response and good immunity on input disturbance. On the basis of theoretical analysis, a systematic simulation of OCC-MR is implemented by means of Matlab/Simulink. Both static state performance and dynamic state performance of OCC-MR are discussed deeply. The simulation results have proved theoretical analysis of the vector operation of OCC-MR, and the control effects are satisfactory.

A dea model with a non discritionary variablefor olympic evaluation

In recent years, a lot of work has been done dealing with alternative performance rankings for the Olympic Games. Almost all of these works use Data Envelopment Analysis (DEA). Generally speaking, those works can be divided into two categories: Pure rankings with unitary input models and relative rankings with classical DEA models; both output oriented. In this paper we introduce an approach taking into account the of as a proxy to the country investment in sports. This is an input for a DEA model, and the other input is the population of the country. We have three outputs,the of gold, silver and bronze medals earned by each country. Contrary to the usual approach in the literature, our model is not output oriented. It is a non-radial DEA model oriented to the number of athletes input, as our goal is not a countries' ranking. We intend to analyse whether the of competing for each country accords with the of won medals. For this analysis, we compare eachcountry with its benchmarks. The Decision Making Units (DMU) are all the countries participating in the Beijing Olympic Games, including those that did not earn a single medal. We use a BCC model and we compare each DMU's target with the of who have won, at least one medal.

Investigation on a Novel Four-Quadrant Power Electronic Transformer

Power Electronic Transformer (PET) has potential application value in distribution network. This paper presents a novel PET with only one stage single-phase to single-phase AC/AC converter at the primary side of the transformer, the high voltage end, which generates high-frequency alternating voltage. The secondary side of the transformer, the low voltage end, is also one stage AC/AC converter, by which low power frequency voltage can be created. The final stage is a resistive converter obtaining low DC output voltage and unitary input power factor. Consequently, the unitary power factor can be reflected to the mains side and the PET owns a four-quadrant operation capability. The theory of four-quadrant PET is analyzed and the simulation analysis using MATLAB/SIMULINK is also provided. The result shows that this kind of PET holds some prominent advantages such as simple structure, easy to control, safe commutation, unitary input power factor, bidirectional power flow and easy to cascade. So it has application value.

Auditory nerve fibers excite targets through synapses that vary in convergence, strength, and short-term plasticity.

Auditory nerve fibers are the major source of excitation to the three groups of principal cells of the ventral cochlear nucleus (VCN), bushy, T stellate, and octopus cells. Shock-evoked excitatory postsynaptic currents (eEPSCs) in slices from mice showed systematic differences between groups of principal cells, indicating that target cells contribute to determining pre- and postsynaptic properties of synapses from spiral ganglion cells. Bushy cells likely to be small spherical bushy cells receive no more than three, most often two, excitatory inputs; those likely to be globular bushy cells receive at least four, most likely five, inputs. T stellate cells receive 6.5 inputs. Octopus cells receive >60 inputs. The N-methyl-d-aspartate (NMDA) components of eEPSCs were largest in T stellate, smaller in bushy, and smallest in octopus cells, and they were larger in neurons from younger than older mice. The average AMPA conductance of a unitary input is 22 ± 15 nS in both groups of bushy cells, <1.5 nS in octopus cells, and 4.6 ± 3 nS in T stellate cells. Sensitivity to philanthotoxin (PhTX) and rectification in the intracellular presence of spermine indicate that AMPA receptors that mediate eEPSCs in T stellate cells contain more GluR2 subunits than those in bushy and octopus cells. The AMPA components of eEPSCs were briefer in bushy (0.5 ms half-width) than in T stellate and octopus cells (0.8-0.9 ms half-width). Widening of eEPSCs in the presence of cyclothiazide (CTZ) indicates that desensitization shortens eEPSCs. CTZ-insensitive synaptic depression of the AMPA components was greater in bushy and octopus than in T stellate cells.

Signal Propagation inDrosophilaCentral Neurons

Drosophila is an important model organism for investigating neural development, neural morphology, neurophysiology, and neural correlates of behaviors. However, almost nothing is known about how electrical signals propagate in Drosophila neurons. Here, we address these issues in antennal lobe projection neurons, one of the most well studied classes of Drosophila neurons. We use morphological and electrophysiological data to deduce the passive membrane properties of these neurons and to build a compartmental model of their electrotonic structure. We find that these neurons are electrotonically extensive and that a somatic recording electrode can only imperfectly control the voltage in the rest of the cell. Simulations predict that action potentials initiate at a location distant from the soma, in the proximal portion of the axon. Simulated synaptic input to a single dendritic branch propagates poorly to the rest of the cell and cannot match the size of real unitary synaptic events, but we can obtain a good fit to data when we model unitary input synapses as dozens of release sites distributed across many dendritic branches. We also show that the true resting potential of these neurons is more hyperpolarized than previously thought, attributable to the experimental error introduced by the electrode seal conductance. A leak sodium conductance also contributes to the resting potential. Together, these findings have fundamental implications for how these neurons integrate their synaptic inputs. Our results also have important consequences for the design and interpretation of experiments aimed at understanding Drosophila neurons and neural circuits.

A ranking for the Olympic Games with unitary input DEA models

There is no official method to establish a final ranking for the Olympic Games. The usual ranking is based on the lexicographic multicriteria method, the main drawback of which is to overvalue gold medals. Furthermore, it does not take into account that the various sports may be of different importance. This work proposes a ranking model to eliminate those drawbacks. We use firstly a modified cross-evaluation data envelopment analysis model with weighted restrictions for each cluster. The outputs are the number of gold, silver and bronze medals and the input is a unitary constant for all countries. After obtaining a rank for each and every cluster, we build a general ranking by aggregation of the partial ones. Our model uses the results of the Athens Olympic Games.

Cross evaluation using weight restrictions in unitary input DEA models

There is no official method to establish a final ranking for the Olympic Games. The usual ranking is based on the Lexicographic Multicriteria Method, the main drawback of which is to overvalue gold...

On the Information Rate of Multiantenna Systems With Isotropic Unitary Input Signals in the Presence of Channel Estimation Errors

This correspondence focuses on the evaluation of the information rate conveyed by block-faded pilot-based multiple-input multiple-output (MIMO) systems when the input signals are isotropic-unitary (IU)-distributed and imperfect (e.g., error-affected) channel estimates are available at receiver and transmitter. Main contributions may be so summarized. First, we develop closed-form analytical formulas for the computation of the ergodic information rate conveyed by the considered MIMO systems equipped with a large number of transmit antennas. Second, we point out that no rate gain may be accomplished by shaping the transmitted streams on the basis of (possibly partial) channel state information (CSI) so that the feedback link becomes, indeed, useless when the system is block faded and fed by IU-distributed input signals. Third, we compare the obtained information rate with those supported by the corresponding MIMO systems fed by Gaussian-distributed input signals for various values of the mean-squared error (MSE) impairing the available MIMO channel estimates. So doing, we gain some insight about the operating conditions where actual implementation of a feedback link may be justified by the resulting improvement in the rate conveyed by the overall system

Capacity of Differential Versus Nondifferential Unitary Space–Time Modulation for MIMO Channels

Differential unitary space–time modulation (DUSTM) and its earlier nondifferential counterpart, USTM, permit high-throughput multiple-input multiple-output (MIMO) communication entirely without the possession of channel state information by either the transmitter or the receiver. For an isotropically random unitary input we obtain the exact closed-form expression for the probability density of the DUSTM received signal, permitting the straightforward Monte Carlo evaluation of its mutual information. We compare the performance of DUSTM and USTM through both numerical computations of mutual information and through the analysis of low- and high-signal-to-noise ratio (SNR) asymptotic expressions. In our comparisons the symbol durations of the equivalent unitary space–time signals are equal to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$T$</tex> . For DUSTM the number of transmit antennas is constrained by the scheme to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$M = T/2$</tex> , while USTM has no such constraint. If DUSTM and USTM utilize the same number of transmit antennas at high SNRs the normalized mutual information of the two schemes expressed in bits/s/Hz are asymptotically equal, with the differential scheme performing somewhat better. At low SNRs the normalized mutual information of DUSTM is asymptotically twice the normalized mutual information of USTM. If, instead, USTM utilizes the optimum number of transmit antennas then USTM can outperform DUSTM at sufficiently low SNRs.

Unified algorithm of single-phase active AC-DC converters and its applications

This paper discusses a novel boost single-phase active AC-DC converters, named low-end semi-controlled bridge AC-DC converter. By analysis, its topology and principle can be derived from the conventional single-phase power factor corrector (PFC). But it has also some differences, such as power device positions, inductor type, input voltage waveform detection and induction current detection, so its design is also different. The converter is implemented by employing two current detection approaches, i.e., current transformer detection and shunt resistor detection. Consequently, it can provide a steady DC output voltage with a low voltage ripple, approximately unitary input power factor and 2.5 kW output power. The experimental results show validity of the theoretical analysis.