Set Of Switches Research Articles

Erratum to Medical Physics article "Principles and applications of multienergy CT: Report of AAPM Task Group 291"

In AAPM Report 291, “Principles and applications of multienergy CT: Report of AAPM Task Group 291,”1 scientists from Canon Medical Systems Corporation, GE Healthcare Technologies, Philips Healthcare, and Siemens Healthcare GmbH participated as authors and contributed sections to describe, in general, the technology used in their company’s dual- or multi-energy CT systems. Specific scanner models were sometimes mentioned to provide examples of the overall approach. The general statements made about the approach may not, however, apply to the specific scanner model used as an example. The intermingling of the general and specific statements is regrettable, as it is ready source of potential confusion. Readers should view each section as a description of an overall dual- or multi-energy CT approach, even if a specific scanner model is mentioned as an example. Readers should refer to manufacturer specifications and the published literature to assess the specifications and performance of a specific CT system. A numerical error exists on page e895 in the second paragraph of the limitations section for kV switching. The statement “… so the system software currently prevents the use of gantry rotation times of less than approximately 500 ms, which may limit the quality of cardiac examinations,” implies that a minimum 500 ms rotation time applies to the scanner used as an example in the kV switching setting (GE Discovery CT750 HD). However, this value (500 msec) does not reflect the minimum rotation time on the GE Discovery CT750 HD. Rather, from the earliest publications on the use of this specific CT scanner model for dual-energy cardiac imaging, the minimum rotation time of 350 ms was used.2, 3 The second and third paragraphs in this same section on the limitations of kV switching reiterate the physics principles discussed on page e894, at the top of the second. Namely, as first demonstrated in 1979 by Kelcz et al., decreased spectral separation causes increased noise in decomposed material-specific images.4 In 2009, Primak et al. demonstrated that tube-specific filtration can increase spectral separation and decrease image noise in material decomposed images using a commercial dual-source CT system.5 While spectral separation is indeed an important determinant of the underlying noise properties of the acquired data, noise reduction methods can be applied such that the material decomposition calculations performed using kV switching (or other non-dual-source approaches) can also yield accurate quantification of iodine concentration.6

Static Reconfiguration of Unbalanced Distribution Systems with Variable Power using Selective Bat Algorithm

Distribution network reconfiguration (DNR) is one of the most studied and important optimization problems in Electrical Engineering field, being well established throughout the years, as seen in the specialized literature. The majority of studies treats the problem in a conservative way, i.e., considering the systems as balanced with fixed demand. However, the real characteristics of distribution systems may take into consideration the unbalanced nature of loads, as well as the variable demand characteristic according to the type of consumer connected. This comes closer to reflect the real operation of such systems, and thus, studies considering DNR with these aspects are becoming more important in recent years. In this context, the paper here presented proposes modeling unbalanced systems with variable demand using a static reconfiguration (SR). As SR considers the whole studied period to define one single set of switches, it is opposed to a dynamic reconfiguration (DR), which is performed in short periods. Considering the load profiles presented, a comparison is made to discuss the advantages and disadvantages of SR in the expanse of DR in unbalanced systems. To solve the DNR problem, a selective bat algorithm (SBAT) is used, as it presents characteristics from particle swarm optimization (PSO) and harmony search (HS). Tests for SR and DR with variable demand are performed in one balanced system (33 buses) and three unbalanced systems (19, 25 and 123 buses). Results for SR using SBAT are compared with selective PSO and selective HS.

Chemically Fueled Volume Phase Transition of Polyacid Microgels

AbstractMicrogels are soft colloids that show responsive behavior and are easy to functionalize for applications. They are considered key components for future smart colloidal material systems. However, so far microgel systems have almost exclusively been studied in classical responsive switching settings using external triggers, while internally organized, autonomous control mechanisms as found in supramolecular chemistry and DNA nanotechnology relying on fuel‐driven out‐of‐equilibrium concepts have not been implemented into microgel systems. Here, we introduce chemically fueled transient volume phase transitions (VPTs) for poly(methacrylic acid) (PMAA) microgels, where the collapsed hydrophobic state can be programmed using the fuel concentration in a cyclic reaction network. We discuss details of the system behavior as a function of pH and fuel amount, unravel kinetically trapped regions and showcase transient encapsulation and time‐programmed release as a first application.

Chemically Fueled Volume Phase Transition of Polyacid Microgels.

Microgels are soft colloids that show responsive behavior and are easy to functionalize for applications. They are considered key components for future smart colloidal material systems. However, so far microgel systems have almost exclusively been studied in classical responsive switching settings using external triggers, while internally organized, autonomous control mechanisms as found in supramolecular chemistry and DNA nanotechnology relying on fuel‐driven out‐of‐equilibrium concepts have not been implemented into microgel systems. Here, we introduce chemically fueled transient volume phase transitions (VPTs) for poly(methacrylic acid) (PMAA) microgels, where the collapsed hydrophobic state can be programmed using the fuel concentration in a cyclic reaction network. We discuss details of the system behavior as a function of pH and fuel amount, unravel kinetically trapped regions and showcase transient encapsulation and time‐programmed release as a first application.

Bridgeless Boost Converter with an Interleaving Manner for PFC Applications

Power quality is a critical issue in power systems. This paper proposes a bridgeless boost converter to increase the power factor of power systems using a utility line source for raising power quality. To reduce input and output current ripple, an interleaving manner is adopted in the proposed power system. When the interleaving bridgeless boost converter is used to implement power factor correction (PFC), it needs two bridgeless boost converters to process power during one switching cycle. In order to simplify the proposed bridgeless boost converter, two sets of switches in the conventional bridgeless boost one are integrated to reduce component counts. With this approach, the proposed bridgeless boost converter uses four switches to implement PFC features. Therefore, the proposed boost converter can increase conversion efficiency and decrease component counts, resulting in a higher conversion efficiency, lower cost and more simplicity for driving circuits. Finally, a prototype with a universal input voltage source (AC 90 V~265 V) under an output voltage of 400 V and a maximum output power of 1 kW has been implemented to verify the feasibility of the proposed bridgeless boost converter.

One-Pass In-Band Automatic Bootstrapping for OpenFlow Switches

An SDN switch newly added to a network needs to establish a control channel with an SDN controller to manage control-plane traffic. The setup of such a channel is termed bootstrapping. In the case of in-band control, bootstrapping involves setting up a control path that may traverse one or more switches between the new switch and the controller, which is achieved through the configuration of layer-two to layer-four parameters on relevant switches. Previous approaches either result in lengthy bootstrapping time due to their level- by-level mechanisms, demand complicated modules, or lack some essential features. This paper proposes an approach to fast automatic bootstrapping that overlaps the bootstrapping processes among a set of switches. Our emulations using virtual switches completed the process of bootstrapping 50 switches arranged in a chain in 2.0 seconds, which is a 98% time reduction compared with a prior study.

Performance Control of the Commutator-and-brush Assembly of the Traction Motor

The operation of the commutator-and-brush assembly largely influences the operational reliability of DC traction motors. Unsatisfactory operating conditions of the commutator-and-brush assembly lead not only to a deterioration in the current collection and damage to the contact surface, but also to a change in the switching setting. Switching quality control must be carried out simultaneously both by the product of the average and average integral durations and by the maximum duration of arc pulses. The paper considers the influence of the quality of commutation on the reliability of the operation of the commutator-and-brush assembly of the traction motor. A method is proposed for assessing the degree of sparking by the duration of arc discharges in comparative tests of electric machines of the same type, which makes it possible to characterize the reliability of the operation of the commutator-and-brush assembly and to take into account all types of causes of commutation failure: both electromagnetic and mechanical ones.

The artificially intelligent switching framework for terminalaccess provides smart routing in modern computer networks

The main page of the web interface provides access to various switch settings and displays all the necessaryinformation about the device. Admins can quickly view device status, performance statistics, etc., as well asmake necessary settings. The switch’s command-line interface is accessed by connecting a terminal or personalcomputer with a terminal emulation program installed on the switch’s console port. In this paper, the intelligentswitching framework was introduced for terminal access to provide smart routing. This access method is mostuseful when connecting to the switch first when the Internet protocol (IP) address is unknown or not set, whenpassword recovery is required, or when performing advanced switch settings. The command line interface can alsobe accessed over the network using the Telnet protocol. The user can use any administrative interface convenientto him to configure the switch because the set of functions available through the different management interfacesis the same for each.

Безопасная реализация виртуальной сети на плоскости данных SDN

The paper continues the investigations on the implementation of virtual networks on the SDN data plane which is modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sender, receiver), and it is implemented by a set of host-host paths that uniquely determine the switch settings. The opportunities to transmit a packet are limited by the host weights (priorities): a packet can be only transmitted from a host to a host if the sender has at most the same priority as the recipient, and thus, a set of paths is permissible if its every subset connects permissible host pairs. In the paper, it is proven that differently from the case when every host pair is permissible, in the graph with priorities a permissible path implementation does not exist for every set of permissible hosts. Moreover, it is shown that is some cases when such an implementation exists, the implementation is not possible without paths with cycles where packets can move infinite and without duplicate paths when a host can get the same packet several times. Using the notion of a perfect set of paths a criterion is established when every permissible set of hosts can be safely implemented by a set of paths without cycles but possibly with duplicate paths.

Large-area growth of MoS2 at temperatures compatible with integrating back-end-of-line functionality

Direct growth of transition metal dichalcogenides over large areas within the back-end-of-line (BEOL) thermal budget limit of silicon integrated circuits is a significant challenge for 3D heterogeneous integration. In this work, we report on the growth of MoS2 films (∼1–10 nm) on SiO2, amorphous-Al2O3, c-plane sapphire, and glass substrates achieved at low temperatures (350 °C–550 °C) by chemical vapor deposition in a manufacturing-compatible 300 mm atomic layer deposition reactor. We investigate the MoS2 films as a potential material solution for BEOL logic, memory and sensing applications. Hall-effect/4-point measurements indicate that the ∼10 nm MoS2 films exhibit very low carrier concentrations (1014–1015 cm−3), high resistivity, and Hall mobility values of ∼0.5–17 cm2 V−1 s−1, confirmed by transistor and resistor test device results. MoS2 grain boundaries and stoichiometric defects resulting from the low thermal budget growth, while detrimental to lateral transport, can be leveraged for the integration of memory and sensing functions. Vertical transport memristor structures (Au/MoS2/Au) incorporating ∼3 nm thick MoS2 films grown at 550 °C (∼0.75 h) show memristive switching and a stable memory window of 105 with a retention time >104 s, between the high-low resistive states. The switching set and reset voltages in these memristors demonstrate a significant reduction compared to memristors fabricated from pristine, single-crystalline MoS2 at higher temperatures, thereby reducing the energy needed for operation. Furthermore, interdigitated electrode-based gas sensors fabricated on ∼5 nm thick 550 °C-grown (∼1.25 h) MoS2 films show excellent selectivity and sub-ppm sensitivity to NO2 gas, with a notable self-recovery at room temperature. The demonstration of large-area MoS2 direct growth at and below the BEOL thermal budget limit, alongside memristive and gas sensing functionality, advances a key enabling technology objective in emerging materials and devices for 3D heterogeneous integration.

Analysis of Cross-Connected Half-Bridges Multilevel Inverter for STATCOM Application

This paper suggested a single-phase cross-connected half-bridges multilevel inverter (cchb-mli) topology for static synchronous compensator (statcom) applications. The proposed mli structure consists of cross-connected multilevel cells connected in series with a more optimized number of devices to synthesize a higher number of voltage steps. Each cell in the structure consists of a set of switches and a dc-capacitor. Typically, when several dc-capacitors are used in an inverter, the dc voltages fluctuation occurs due to tolerance between passive element and asymmetric switch losses. A dual-loop control technique has been proposed with level-shifted pulse width modulation pwm to overcome these issues. The proposed methodology balances the dc-voltages using a proportional-integral controller by adjusting the switch duty cycle. The control method helps offset the issue of aggravated fluctuation while preserving the delivered reactive power distributed equally among the dc-capacitors at the same time. A thorough comparison is made between the proposed inverter concerning the number of components and efficiency to demonstrate the effectiveness of previous topologies. Moreover, a simulation model built in simulink and experimental results take from laboratory prototype to confirm the effectiveness of proposed structure and its control technique.

Mapping Parallel Computations to Distributed Systems Based on RapidIO Technology

This paper is devoted to the problem of mapping parallel computations to distributed systems based on RapidIO communications. A distributed system is represented as a set of hosts with given levels of performance and a set of switches interconnected by links with known bandwidths. Parallel computation is specified as a number of processes that communicate by passing data streams. Each process requires certain performance and each data stream requires certain network bandwidth. It is necessary to map processes to hosts, as well as define routes for data streams and routing tables for switches, in such a way that the performance requirements of processes and bandwidth requirements of data streams are met. In general, this task is NP-complete. We propose an approach based on integer linear programming (ILP) methods that provides correct mapping of parallel computations to a distributed system and enables optimization of the map with respect to a number of parameters.

Analysis of discontinuous dynamics of a 2-DOF system with constrained spring cushions

We investigate the dynamical characteristics of a two degrees of freedom friction oscillator with constrained spring cushions. Based on the discontinuity resulted from the rough contact surface and the nonsmoothness resulted from fixed spring, different boundaries and domains are given in phase space. The G-functions are introduced to determine whether the passable, grazing, sliding and stick motions occur on separation boundaries. The periodic orbits in such a system are predicted by using mapping dynamical theory after introducing four-dimension switching sets and basic mappings. The passable, grazing, stick, sliding and periodic motions of system are studied numerically by the velocity, displacement and G-functions responses in order to better illustrate the switching conditions of different motions. This investigation can provide effective technical support for the optimization design of system with fixed spring cushions.

Perancangan Sistem Pendingin Photovoltaic dengan Memanfaatkan Kontroler Water Spray

Temperature is one of the parameters other than radiation that can affect the performance of photovoltaic (PV) in relation to the output power and efficiency. This paper discusses the design of the PV cooling system using waters pray that controlled automatically. The temperature of the PV on the sensor as input to the controller and the output is the switch settings to turn on/off the pump in spraying water to the surface of the PV panel with the intention that the PV is always maintained at normal temperatures. The system was tested simultaneously on 4 PV panels @ 100Wp by involving PV without a cooling system with the same capacity during the day and the result was compared. Based on the results of PV temperature measurements in relation to the output power shows that PV with a cooling system generates higher output power than PV without a cooling system. By taking into account the involvement of power consumed by the cooling system consists of a controller and pump, the efficiency of PV rises slightly to 1.07 times.

2-Vertex self switching of umbrella graph

By a graph \(G=(V, E)\) we mean a finite undirected graph without loops or multiple edges. Let \(G\) be a graph and \(\sigma \subseteq V\) be a non-empty subset of \(V\). Then \(\sigma\) is said to be a self switching of \(G\) if and only if \(G \cong G^\sigma\). It can also be referred to as \(|\sigma|\)-vertex self-switching. The set of all self switching of the graph \(G\) with cardinality \(k\) is represented by \(S_k(G)\) and its cardinality by \(s s_k(G)\). A vertex \(v\) of a graph \(G\) is said to be self vertex switching if \(G \cong G^v\). The set of all self vertex switchings of \(G\) is denoted by \(\operatorname{SS}_1(G)\) and its cardinality is given by \(s s_1(G)\). If \(|\sigma|=2\), we call it as a 2-vertex self switching. The set of all 2-vertex switchings of \(G\) is denoted by \(\operatorname{SS}_2(G)\) and its cardinality is given by \(s s_2(G)\). In this paper we find the number of 2-vertex self switching vertices for the umbrella graph \(U_{m, n}\).

Event-Triggered Switching-Type Fault Detection and Isolation for Fuzzy Control Systems Under DoS Attacks

This article investigates the memory adaptive event-triggered fault detection and isolation (FDI) problem for nonlinear networked control systems under periodic denial-of-service (DoS) attacks, where the nonlinear systems are described by Takagi–Sugeno (T–S) fuzzy models with unknown membership functions. First, a novel event-triggered mechanism is proposed to save communication resources. The triggering threshold is adaptively adjusted by multiple previous sampled data, not only depending on the latest triggering data. Second, taking DoS attacks, and event-triggered mechanism into consideration, a switching state-feedback controller is established, and the exponential stability is derived. Meanwhile, the controller, and the event-triggered mechanism are simultaneously developed based on a piecewise Lyapunov function. Then, a set of switching T–S fuzzy observers are constructed to realize FDI under DoS attacks. Besides, a switching variable method is introduced to address the asynchronous premise variables problem caused by the event-triggered mechanism. Finally, simulation cases are given to demonstrate the validity, and merit of the proposed FDI scheme.

Analysis of dynamical behaviors of a 2-DOF friction oscillator with elastic impacts and negative feedbacks

In this paper, the flow switching theory of discontinuous dynamical systems is used as the main tool to study the dynamical behaviors of a two-degree-of-freedom friction oscillator with elastic impacts, where considering that the inequality of static and kinetic friction forces results in the existence of flow barriers at the relative velocity between the mass and conveyor belt tending to zero. The negative feedback is also taken into account, $$\mathrm {i.e.}$$ , when the direction of the relative velocity between the mass and conveyor belt changes, the constant force in the periodic excitation force will also change to adapt to the variation in speed. Due to the discontinuity resulted from the friction and non-smoothness resulted from impact, the motion of the two masses can be divided into the following kinds: non-sliding motion (or free motion), sliding motion, non-sliding–stick motion and sliding–stick motion, and the phase space in system is divided into different domains and boundaries, where the vector field is continuous in each region but discontinuous on the velocity boundary. The corresponding normal vectors and G-functions on the separation boundaries are introduced to acquire the switching conditions for all possible motions such as passable motion, sliding motion, grazing motion and stick motion. The mapping theory provides an effective method for the discussion of periodic motion in discontinuous dynamical systems. The four-dimensional switching sets are defined by the means of the form of direct product of two-dimensional switching sets, and the mapping structures are introduced based on the switching sets to describe periodic motions. Eventually, in order to explain more intuitively the above motions in such a friction–impact system, the velocity, displacement, G-functions time histories and the trajectories in phase plane for the masses are illustrated by simulation numerically.

A Multi-Level Power Converter Interface for a Battery Energy Storage System

— This study proposes a multi-level power converter for a battery energy storage system (BESS) with bidirectional power flow. The multi-level power converter includes a DC-DC power converter, a selection switch set and a full-bridge inverter. The DC-DC power converter performs bidirectional power conversion and provides a DC voltage that is greater than the peak voltage of the utility. Integrating the selection switch set and the full-bridge inverter produces a five-level AC voltage that controls the real power flow and the reactive power flow between the battery set, the DC-DC power converter and the grid. Because partial power is directly processed using only the selection switch set and the full-bridge inverter, the DC-DC power converter is operated only when the grid voltage is greater than the voltage of the battery set. Therefore, the power conversion efficiency for the proposed BESS is improved. The proposed BESS uses only eight power electronic switches, so the power circuit is simplified. A hardware prototype with a digital signal processor controller is used to verify the performance of the proposed BESS. The experimental results are as expected.

Electronically Tunable VDTA-Based Multi-function Inverse Filter

An electronically tunable realization of voltage differencing transconductance amplifier (VDTA)-based multi-function inverse filter circuit is proposed in this letter. Various responses namely inverse low pass, inverse high pass, inverse band pass, and inverse band reject are achieved through switch settings. The proposed circuit uses only grounded capacitors and adds electronic tunability to filter parameters through bias currents of VDTA. SPICE simulations using TSMC 180 nm CMOS technology parameter are carried out to examine operation, total harmonic distortion and noise performance of proposal. Monte Carlo simulations are performed to study performance of the proposal under simultaneous variation in passive component values, oxide thickness and transistor threshold voltage.

Non-fragile guaranteed-performance [formula omitted] leader-following consensus of Lipschitz nonlinear multi-agent systems with switching topologies

In this paper, the problem of non-fragile guaranteed-performance H∞ leader-following consensus protocol design for high-order multi-agent systems with Lipschitz nonlinearities and switching topologies is investigated. The communication interactions among all agents are described by a set of switching directed graphs, whose union contains a directed spanning tree rooting at the leader node. By constructing a nonsingular transformation, leader-following consensus of the concerned multi-agent system is transformed into the problem of asymptotic stability analysis for some consensus error systems. Taking into account the existences of exogenous disturbances in practical agent systems and gain perturbations in physical controller implementations, the non-fragile H∞ criterion is introduced not only to design the consensus protocol which is capable of tolerating some level of parametric uncertainties, but also to make the consensus error system asymptotically stable with a prescribed H∞ disturbance attenuation level. To regulate the consensus performance, a quadratic function collecting consensus errors among in-neighboring agents is proposed. By employing tools from algebraic graph theory and Lyapunov functional technique, sufficient conditions on the desired consensus protocol design are derived in terms of linear matrix inequalities. Simulation illustrates the effectiveness of the theoretical results.