Common Control Signal Research Articles

A Unidirectional Hierarchical Control Structure With Zero Power Sharing Error for Hybrid AC/DC Microgrid

The desire for decreasing the stress on the individual AC and DC sources motivates accurate load sharing in Hybrid AC/DC microgrids (HMGs). The conventional hierarchical control scheme suffers from error in active power sharing among the DC sources and inaccurate reactive power sharing in the AC microgrid, which result from the local property of voltage. To circumvent this issue, a unidirectional hierarchical control scheme, which employs a combination of central and local secondary controllers is proposed in this paper. For each of the DC and AC microgrids, the central secondary controller eliminates the voltage/frequency deviations through a common control signal, which is broadcasted to the sources and interlink converter (IC). In addition, the DC and AC PCC voltages are broadcasted to the sources and IC. The local secondary controller (power sharing correction unit) of each source alters the central secondary control signal based on the PCC voltage. By incorporation of the PCC voltage in the droop characteristics of the sources and the control loop of IC, the error in active/reactive power sharing is eliminated. The stability of the proposed scheme is analyzed through small signal analysis. Simulation and experimental results are presented to validate the proposed control method.

Strongly Uncontrollable Network Topologies

In this paper, we present a class of network topologies under which the Laplacian consensus dynamics exhibits undesirable controllability properties under a broadcast control signal. Specifically, the networks we characterize are uncontrollable for any subset of the nodes chosen as control inputs and that emit a common control signal. We provide a sufficient condition for a network to contain this strong uncontrollability property and describe network perturbations that leave the uncontrollability property invariant. As a by-product, we identify non-trivial network topologies that require the control of approximately half the nodes in the network as a necessary condition for controllability.

A common control signal and a ballistic stage can explain the control of coordinated eye-hand movements.

Voluntary control has been extensively studied in the context of eye and hand movements made in isolation, yet little is known about the nature of control during eye-hand coordination. We probed this with a redirect task. Here subjects had to make reaching/pointing movements accompanied by coordinated eye movements but had to change their plans when the target occasionally changed its position during some trials. Using a race model framework, we found that separate effector-specific mechanisms may be recruited to control eye and hand movements when executed in isolation but when the same effectors are coordinated a unitary mechanism to control coordinated eye-hand movements is employed. Specifically, we found that performance curves were distinct for the eye and hand when these movements were executed in isolation but were comparable when they were executed together. Second, the time to switch motor plans, called the target step reaction time, was different in the eye-alone and hand-alone conditions but was similar in the coordinated condition under assumption of a ballistic stage of ∼40 ms, on average. Interestingly, the existence of this ballistic stage could predict the extent of eye-hand dissociations seen in individual subjects. Finally, when subjects were explicitly instructed to control specifically a single effector (eye or hand), redirecting one effector had a strong effect on the performance of the other effector. Taken together, these results suggest that a common control signal and a ballistic stage are recruited when coordinated eye-hand movement plans require alteration.

Design Methodologies for Reversible Logic Based Barrel Shifters

Barrel shifter is an integral component of processor datapaths in computing systems since it can shift and rotate multiple bits in a single cycle. Furthermore, reversible logic has applications in emerging computing paradigms such as quantum computing, quantum dot cellular automata, optical computing, etc. In this work, we propose efficient methodologies for designing reversible barrel shifters. The proposed methodologies are designed using Fredkin gate and Feynman gate (FG). The Fredkin gate is used because it can implement a 2:1 MUX with minimum quantum cost, minimum number of ancilla inputs and garbage outputs, and the Feynman gate is used to avoid a fanout since a fanout is not allowed in reversible logic. In the existing literature, design methodologies are limited to the design of a ([Formula: see text]) reversible left rotator that can only perform the left rotate operation. This work explores the other primary functionalities of a reversible barrel shifter such as the design of a reversible: (i) logical right shifter, (ii) universal right shifter that supports logical right shifter, arithmetic right shifter and right rotate operation, (iii) bidirectional logical shifter and (iv) universal bidirectional shifter that supports bidirectional logical and arithmetic shifter and rotate operations. The other types of reversible barrel shifters can also be easily designed by making minor modifications in the proposed methodologies. The proposed design methodologies are generic in nature and can be implemented using any barrel shifter of ([Formula: see text]) size, where n and k are the number of data bits and shift value, respectively. In order to minimize the number of ancilla inputs and garbage outputs, strategies such as the implementation of an n number of 2:1 MUXes as a chain of n Fredkin gates and the mapping of the two different 2:1 MUXes that are controlled by a common control signal but having the swapped controlled signals on a single Fredkin gate, are utilized. The design methodologies are evaluated in terms of the number of garbage outputs, the number of ancilla inputs and quantum cost. For a ([Formula: see text]) reversible barrel shifter, the relations between the varying values of n and k and their impact on the number of garbage outputs, the number of ancilla inputs and quantum cost are also established to help the designers in choosing an efficient barrel shifter according to their design needs.

Role of the anterior insular cortex in integrative causal signaling during multisensory auditory-visual attention.

Coordinated attention to information from multiple senses is fundamental to our ability to respond to salient environmental events, yet little is known about brain network mechanisms that guide integration of information from multiple senses. Here we investigate dynamic causal mechanisms underlying multisensory auditory-visual attention, focusing on a network of right-hemisphere frontal-cingulate-parietal regions implicated in a wide range of tasks involving attention and cognitive control. Participants performed three 'oddball' attention tasks involving auditory, visual and multisensory auditory-visual stimuli during fMRI scanning. We found that the right anterior insula (rAI) demonstrated the most significant causal influences on all other frontal-cingulate-parietal regions, serving as a major causal control hub during multisensory attention. Crucially, we then tested two competing models of the role of the rAI in multisensory attention: an 'integrated' signaling model in which the rAI generates a common multisensory control signal associated with simultaneous attention to auditory and visual oddball stimuli versus a 'segregated' signaling model in which the rAI generates two segregated and independent signals in each sensory modality. We found strong support for the integrated, rather than the segregated, signaling model. Furthermore, the strength of the integrated control signal from the rAI was most pronounced on the dorsal anterior cingulate and posterior parietal cortices, two key nodes of saliency and central executive networks respectively. These results were preserved with the addition of a superior temporal sulcus region involved in multisensory processing. Our study provides new insights into the dynamic causal mechanisms by which the AI facilitates multisensory attention.

Feasibility Study of a Wirelessly Controlled and Powered Space-Fed Phased Array Antenna

A space-fed X-band phased array antenna (PAA) is presented. The space-fed PAA uses physically autonomous individually addressable unit cells as the building blocks of an arbitrarily large array antenna. The X-band PAA unit cell consists of both a feed facing printed antenna element and a target facing printed antenna element. These elements are related by an RF phase shifter placed in the RF signal path between them which introduces relative phase delay and enables analog beam forming. Unit cell autonomy is realized by wirelessly transferring power and command signals required to operate a microcontroller (MCU) and the RF phase shifter at each unit cell. Each unit cell includes RF to DC conversion circuitry as well as an MCU designed to interpret a common control signal and command unit cell phase delay. The wireless phased array unit cell can be replicated in configurations of size and shape that are independent of RF, power, and array module control distribution networks. To demonstrate feasibility a four-element wireless PAA is constructed and antenna patterns for various control states are shown.

Controllability of Multi‐Agent Dynamical Systems with a Broadcasting Control Signal

AbstractThis paper is concerned with the controllability of a multi‐agent dynamical system in which all identical first‐order dynamical agents receive a common exogenous control signal in addition to their inter‐agent communications. Existing graph theoretic results are used to determine conditions for controllability, and to study the dependency of controllability on the size of network and the number of connections. The fragility of controllability in the presence of hidden or broken connections is also investigated.

Coverage Performance of Common/Shared Control Signals Using Transmit Diversity in Evolved UTRA Downlink

This paper presents the best transmit diversity schemes for three types of common/shared control signals from the viewpoint of the block error rate (BLER) performance in the Evolved UTRA downlink employing OFDM radio access. This paper also presents the coverage performance of the common/shared control signals using transmit diversity with respect to the outage probability that satisfies the required BLER performance, which is a major factor determining the cell configuration. Simulation results clarify that Space-Frequency Block Code (SFBC) and the combination of SFBC and Frequency Switched Transmit Diversity (FSTD) are the best transmit diversity schemes among the open-loop type transmit diversity candidates for two-antenna and four-antenna transmission cases, respectively. Furthermore, we show through system-level simulations that SFBC is very effective in reducing the outage probability at the required BLER for the physical broadcast channel (PBCH), for the common control signal with resource block (RB)-level assignment such as the dynamic broadcast channel (D-BCH) and paging channel (PCH), and in increasing the number of accommodated L1/L2 control signals over one transmission time interval duration, using mini-control channel element (CCE)-level assignment.

A Study on the Different System Detection Method Among Different Type PLC Systems

Coexistence method when various different type PLC (Power Line Communication) systems exist on the same electric power line is not so considered though these systems have already been used. In this paper, we will propose the different system detection method in the environment like above-mentioned and a common wideband control signal with the robustness to be able to communicate each other even in some harsh environments of the electric power line. Therefore a plural of different type systems can coexist even when those systems are used on the same electric power line because of using the common wideband signal for the proposed different system detection method. For example, power line channel is divided into a control region and a data transmission region with the synchronized timing of AC zero crossing in the proposed method. The proposed common wideband signal is used in order to allocate each communication band for each different type system in the control region. In the computer simulation, several carrier detection probabilities were calculated in AWGN (Added White Gaussian Noise) channel and the 80 simulated channels based on the channel data which were measured in the U.S. These results show that the proposed control signal for the different system detection method is robust enough to use in the power line.

System Analysis of a DoD Print Head for Direct Writing of Conductive Circuits

The inkjet‐printing principle is becoming more and more important for new applications besides conventional graphic printing. The target at our institute is to print conductive silver lines and areas of different widths and thicknesses. Based on a drop‐on‐demand (DoD) micro feeding system, a colloidal ink printer was developed to print conductive circuits. The printer has a stationary piezo‐driven print head with a nozzle diameter of 100 μm. With such a nozzle, conductive paths with a width between 110 and 250 μm can be realized. A waveform generator is used to actuate the print head's piezo actuator. The most common control signal is a nearly rectangular voltage pulse. Shape, duration, and amplitude of the piezo control signal influence the stability of the printing process and thus the quality of the printed electrical structures significantly. Different rise and dwell times or pulse shapes can be considered to optimize the printing process. In this article, the piezo control signal's shape is analyzed, varied and the print head's system behavior is characterized. In a performance and signal analysis, the influence of the piezo input signal's shape on the transient behavior of the piezo output energy signal is identified. An optimized piezo control signal shall be achieved. In conclusion, a method is presented to measure droplet parameters such as radius, speed, and volume.

An Untethered, Electrostatic, Globally Controllable MEMS Micro-Robot

We present an untethered, electrostatic, MEMS micro-robot, with dimensions of 60 /spl mu/m by 250 /spl mu/m by 10 /spl mu/m. The device consists of a curved, cantilevered steering arm, mounted on an untethered scratch drive actuator (USDA). These two components are fabricated monolithically from the same sheet of conductive polysilicon, and receive a common power and control signal through a capacitive coupling with an underlying electrical grid. All locations on the grid receive the same power and control signal, so that the devices can be operated without knowledge of their position on the substrate. Individual control of the component actuators provides two distinct motion gaits (forward motion and turning), which together allow full coverage of a planar workspace. These MEMS micro-robots demonstrate turning error of less than 3.7/spl deg//mm during forward motion, turn with radii as small as 176 /spl mu/m, and achieve speeds of over 200 /spl mu/m/sec with an average step size as small as 12 nm. They have been shown to operate open-loop for distances exceeding 35 cm without failure, and can be controlled through teleoperation to navigate complex paths. The devices were fabricated through a multiuser surface micromachining process, and were postprocessed to add a patterned layer of tensile chromium, which curls the steering arms upward. After sacrificial release, the devices were transferred with a vacuum microprobe to the electrical grid for testing. This grid consists of a silicon substrate coated with 13-/spl mu/m microfabricated electrodes, arranged in an interdigitated fashion with 2-/spl mu/m spaces. The electrodes are insulated by a layer of electron-beam-evaporated zirconium dioxide, so that devices placed on top of the electrodes will experience an electrostatic force in response to an applied voltage. Control waveforms are broadcast to the device through the capacitive power coupling, and are decoded by the electromechanical response of the device body. Hysteresis in the system allows on-board storage of n=2 bits of state information in response to these electrical signals. The presence of on-board state information within the device itself allows each of the two device subsystems (USDA and steering arm) to be individually addressed and controlled. We describe this communication and control strategy and show necessary and sufficient conditions for voltage-selective actuation of all 2/sup n/ system states, both for our devices (n=2), and for the more general case (where n is larger.).

Multichannel masking sound generator

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Regulation of thymidine kinase enzyme level in serum-stimulated mouse 3T6 fibroblasts

This report describes the regulation of thymidine kinase (TK) enzyme level in mouse 3T6 fibroblasts experiencing a serum-induced transition between the resting (G0) and growing states. The specific activity of TK is about 200–500 pmoles TMP formed × min −1 × mg protein −1 in exponentially growing cells but is scarcely detectable (usually less than 5 pmoles TMP formed × min −1 × mg protein −1) in cells resting at confluence in medium containing 0.5 % serum. When the resting cells are serum-stimulated to re-enter the cell cycle, TK activity remains at the resting level until about 12 h following stimulation, but then increases dramatically as the cells enter S phase. Experiments with inhibitors of protein or RNA synthesis indicate that the increase in enzyme level is the result of de novo synthesis of the enzyme, and that the increase depends on transcription. The increase in TK level is not blocked when cells are stimulated in the presence of inhibitors of DNA synthesis, indicating that there is no tight coupling between these two processes. The increase is not blocked by the presence of thymidine ranging in concentration from 10 −7 to 10 −3 M, suggesting that fluctuations in the intracellular concentrations of thymidine or thymidylic acid do not affect the increase in TK level. When cells are treated with cycloheximide, the level of TK decreases with a 4–5 h half-life, indicating that the enzyme is relatively unstable. When the serum stimulus is withdrawn from cells in S phase (20 h following stimulation), the TK level decreases with the same 4 h half-life beginning about 6 h following serum withdrawal. The ability of the cell to control the rate of production of TK over a very wide range, along with the relative instability of the enzyme appear to be responsible for the rapid and wide variations in TK level during the cell cycle. The increase in the level of TK appears to be regulated in a manner similar to that of dihydrofolate reductase and thymidylate synthetase in serum-stimulated 3T6 cells, suggesting that the expression of these genes (and perhaps those for other S phase enzymes) may be coordinated by a common control signal.