Balanced Topology Research Articles

Energy balance and robustness adjustable topology control algorithm for wireless sensor networks

In wireless sensor networks, the interference around the application environment may cause the actual distance between any pair of nodes to fail to be measured accurately. Enclosure graph (EG) model uses this distance between nodes as its weight to construct the topology, which does not fully consider the interference. Consequently it will lead to a large amount of energy consumption induced by the application environment. Even it shortens the survival time. According to the feature of network energy inequality in a wireless sensor network and the defect of EG, we first introduce the adjustable factor of node degree, establish a model of communication metric and a model for the node actual survival time. Then according to the demand of network energy equalization and maximum network lifetime, we quantitatively analyze the network node degree, and achieve its regular pattern. In accordance with this regular pattern and sufficient conditions of function extremum, the maximum node energy consumption and the maximum node actual survival time are deduced. And the corresponding optimal node degree is achieved. Finally, according to the above model, in this paper we propose an energy balance and robustness adjustable topology control algorithm for wireless sensor networks. Theoretical analyses show that this algorithm can guarantee that the network is connected and the link of the network is bi-directionally connected. Experiments show that the network takes advantage of this optimal node degree to obtain the high robustness, thus guaranteeing that the information can be transferred unfailingly. This algorithm can effectively balance the node energy, improve the node survival time, enhance the network robustness, and prolong the network's lifetime.

Nonlinear protocols for distributed consensus in directed networks of dynamic agents

This paper deals with the distributed consensus problem of multi-agent systems. While existing work mainly considers the design of linear protocols, we derive nonlinear protocols for directed networks of dynamic agents with fixed and switched topologies, respectively. The obtained nonlinear protocols have the same effectiveness as the existing linear protocols, however they can satisfy the input constraints of real world physical systems, as well as the state value restrictions of agents, which ensure the smooth communication of the whole network and the correct data transmission among agents under the limited bandwidth. In contrast to most existing approaches that commonly use the Lyapunov function theory in order to prove the consensus problem, simple and effective mathematical methods are developed here for this purpose. Based on the equivalent infinitesimal functions and differentials as well as linear approximations as comparatively simple mathematical tools, we prove that the distributed consensus is asymptotically reachable and derive the group decision values. For balanced topology structures, these nonlinear protocols in particular guarantee that the agents asymptotically reach an average-consensus. Furthermore, the obtained protocols relax the constraints on the communication links among the agents. Finally, simulations comprising the vertical alignment maneuver of a team of unmanned aerial vehicles (UAVs) and the phase synchronization of three oscillators are studied, respectively. The simulation results underline that the developed nonlinear protocols are effective and feasible for distributed consensus in directed networks of dynamic multi-agent systems.

A 134 GHz <formula formulatype="inline"><tex Notation="TeX">${+}4$</tex> </formula> dBm Frequency Doubler at <formula formulatype="inline"> <tex Notation="TeX">$f_{\max}$</tex></formula> in 130 nm CMOS

A +4 dBm 134 GHz frequency doubler operating at the maximum oscillation frequency (fmax) of the technology is shown in an IBM 130 nm CMOS process. The doubler is implemented in a balanced topology, driven by a chain of stacked Class-AB amplifiers, and generates the highest reported power in 130 nm CMOS beyond 100 GHz. A theoretical study of frequency doublers is presented including scaling trends across frequency and CMOS technology nodes.

TDOA Wireless Localization Comparison Influence of Network Topology

The interest to wireless positioning techniques has been increasing in recent decades due to wide spread of location-based services as well as constraints imposed by regulator on cellular operator to achieve an accepted level of cellular accuracy regardless of availability of GPS signals. Nevertheless, failure of some base stations cannot be fully avoided, yielding various cellular topologies, which, in turn would likely influence the accuracy of the positioning. This paper explores four types of cellular topologies: balanced, circular, U-shape and linear, which can be inferred from balanced topology structure. Assuming time difference of arrival technology and, up to some extent, time of arrival technology were employed, least square like methods are contrasted with maximum likelihood, Taylor, Chan and hybrid approaches in a simulation platform

Network Topology Algorithm Based on Energy-consumption Optimization of Multi-hop Wireless Networks

A balanced topology intervention algorithm based on energy-consumption optimization is presented in this paper. Multilayer sequence planning algorithm is firstly adopted to convert the nonlinear optimization problem into edge-stirring mechanism and node-stirring mechanism so as to independently optimize these sub-problems, and then the solutions of these problems are adopted to analyze the potential balanced performance between energy consumption and average path-length in the networks. Through simulation under different network scale and operational requirement, the validity and applicability of the algorithm are verified. In addition, we have found the balance point between edge-stirring mechanism and node-stirring mechanism in the network with energy and throughput constraints

Disrupted topological properties of brain white matter networks in left temporal lobe epilepsy: A diffusion tensor imaging study

Mesial temporal lobe epilepsy (mTLE) is the most common drug-refractory focal epilepsy in adults. Although previous functional and morphological studies have revealed abnormalities in the brain networks of mTLE, the topological organization of the brain white matter (WM) networks in mTLE patients is still ambiguous. In this study, we constructed brain WM networks for 14 left mTLE patients and 22 age- and gender-matched normal controls using diffusion tensor tractography and estimated the alterations of network properties in the mTLE brain networks using graph theoretical analysis. We found that networks for both the mTLE patients and the controls exhibited prominent small-world properties, suggesting a balanced topology of integration and segregation. However, the brain WM networks of mTLE patients showed a significant increased characteristic path length but significant decreased global efficiency, which indicate a disruption in the organization of the brain WM networks in mTLE patients. Moreover, we found significant between-group differences in the nodal properties in several brain regions, such as the left superior temporal gyrus, left hippocampus, the right occipital and right temporal cortices. The robustness analysis showed that the results were likely to be consistent for the networks constructed with different definitions of node and edge weight. Taken together, our findings may suggest an adverse effect of epileptic seizures on the organization of large-scale brain WM networks in mTLE patients.

Design and Analysis of a $Ka$-Band Monolithic High-Efficiency Frequency Quadrupler Using GaAs HBT–HEMT Common-Base/Common-Source Balanced Topology

A Ka-band monolithic high-efficiency frequency quadrupler using a GaAs heterojunction bipolar transistor and pseudomorphic high electron-mobility transistor technology is presented in this paper. The frequency quadrupler is constructed cascading two frequency doublers. The frequency doubler employs a modified common-base/common-source topology to enhance the second harmonic efficiently. The dc bias condition, harmonic output power, conversion gain, and efficiency for variable configurations are investigated. Two phase-shifter networks are used to reduce phase error and improve the fundamental rejection. Between 23-30 GHz, the proposed frequency quadrupler features a conversion gain of higher than -1 dB with an input power of 4 dBm. The maximum conversion gain is 2.7 dB at 28 GHz with an efficiency of up to 8% and a power-added efficiency of 3.6%. The maximum output 1-dB compression point (P1 dB) and the saturation output power (Psat) are higher than 7 and 8.2 dBm, respectively. The overall chip size is 2×1 mm2.

Resources searching method for unstructured peer-to-peer networks based on shortcuts between subtrees

Through studying resources searching methods of unstructured Peer-to-Peer(P2P) network,a new P2P overlay network was proposed.Using a multi-way balanced tree topology,the network created shortcuts between the added node and each subtree of the root when a new node inserted,which forwarded first-hop of a query message only,and then query messages could be forwarded in parallel in each subtree of the root without relying on the root.Compared with the performance of Gnutella and Random Walks network in simulation,the proposed network had lower messages redundancy ratio,higher resource searching success ratio and lower average searching time complexity.The analytical results show that the proposed network is efficient and feasible for searching resources.

SOC Based Battery Cell Balancing with a Novel Topology and Reduced Component Count

This paper proposes a novel battery cell balancing topology with reduced component count and simplified control. The balancing algorithm is based on the state of charge (SOC) of each individual cell instead of cell voltage. The principle of the proposed topology is analyzed and verified through simulation and experiments. Then an experimental battery test workbench is established to validate the proposed balancing algorithm. The experimental results show that the proposed balancing topology and associated algorithm can perform well in real applications.

Single Switched Capacitor Battery Balancing System Enhancements

Battery management systems (BMS) are a key element in electric vehicle energy storage systems. The BMS performs several functions concerning to the battery system, its key task being balancing the battery cells. Battery cell unbalancing hampers electric vehicles’ performance, with differing individual cell voltages decreasing the battery pack capacity and cell lifetime, leading to the eventual failure of the total battery system. Quite a lot of cell balancing topologies have been proposed, such as shunt resistor, shuttling capacitor, inductor/transformer based and DC energy converters. The shuttling capacitor balancing systems in particular have not been subject to much research efforts however, due to their perceived low balancing speed and high cost. This paper tries to fill this gap by briefly discussing the shuttling capacitor cell balancing topologies, focusing on the single switched capacitor (SSC) cell balancing and proposing a novel procedure to improve the SSC balancing system performance. This leads to a new control strategy for the SSC system that can decrease the balancing system size, cost, balancing time and that can improve the SSC balancing system efficiency.

Leader-Following Consensus of Linear Multiagent Systems with State Observer under Switching Topologies

The leader-following consensus problem of higher order multiagent systems is considered. The dynamics of each agent are given in general form of linear system, and the communication topology among the agents is assumed to be directed and switching. To track the leader, two kinds of distributed observer-based consensus protocols are proposed for each following agent, whose distributed observers are used to estimate the leader’s state and tracking error based on the relative outputs of the neighboring agents, respectively. Some sufficient consensus conditions are established by using parameter-dependent Lyapunov function method under a class of directed interaction topologies. As special cases, the consensus conditions for balanced and undirected interconnection topology cases can be obtained directly. The protocol design technique is based on algebraic graph theory, Riccati equation, and Sylvester equation. Finally, a simulation example is given to illustrate our obtained result.

A balanced dual-resonance colpitts VCO in 0.18 μm CMOS

A dual-resonance balanced voltage-controlled oscillator (VCO) is proposed to serves as a dual-band oscillator operated at 3.5 and 8.5 GHz. The VCO consists of two single-ended dual-resonance LC-tank complementary Colpitts oscillators configured in a balanced topology. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology and the core power consumption is 4.21 mW at the supply voltage of 1.2 V. The figure of merit is −190.22/−190.3 dBc/Hz at high/low band. The die area of the dual-band VCO is 0.995 × 0.55 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:194–197, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27234

A Triple-Mode Balanced Linear CMOS Power Amplifier Using a Switched-Quadrature Coupler

A triple-mode class-AB balanced linear power amplifier (PA) is realized in standard 0.18-μm CMOS technology. For the average efficiency enhancement, the triple-mode operation realizes a switched-quadrature coupler with a balanced topology to achieve robust load insensitivity. The PA and RF switches uniquely utilize the isolation port of the switched-quadrature coupler as a signal path in a low-power (LP) mode of operation, and the incorporated output matching network satisfies the |Γ| = 1 condition from the quadrature coupler in the LP mode while providing the necessary load-pull impedance from the PA output side in the high-power (HP) mode. To obtain low loss and high quality factor ( Q) of the passive output-combining network, a transformer-based quadrature coupler is implemented using a silicon-based integrated passive device process. With a 3.4-V power supply, the PA transmits a maximum output power of 28.4 dBm with 40.7% of power-added efficiency (PAE) and linear output power up to 26.6 dBm with 35% of the PAE using a 3-GPP WCDMA modulated signal. With the triple-mode operation, a PAE at 16 dBm is enhanced from 11.1% to 17%, and 47 mA of quiescent current is saved. The PA also shows robust operation under 2.5:1 of VSWR condition, achieving 1 dB of the gain variation and less than 3.9 dB of ACLR variation. This work demonstrates the potential of a highly efficient CMOS PA for WCDMA applications.

Capacitor Based Battery Balancing System

Battery systems as a vital part of the electrical vehicles are facing major difficulties, the most important matter is the cells unbalancing. The cells unbalancing leads to individual cell voltages differ over time, decreasing the battery pack capacity that consequently will fail of the total battery system in the long run. In addition, cell equalization acts an important role on the battery life preserving. Several cell balancing topologies have been proposed for battery pack equalization such as; switched shunt resistors, inductor/transformer base, shuttling capacitor and energy converters. Quite a few researches focused the capacitor base cell balancing. This paper is presents a review, comparisons and develop the capacitor based topologies for balancing battery string. With the aid of MATLAB/Simulink® modeling, the switched capacitor topologies have been proposed including circuits, cells balancing simulation, implementations, balancing speed, complexity and system efficiency, as well as, propose a new control strategy for the single switched capacitor.

Cancellation of the parasitic feedthrough current in an integrated CMOS–MEMS clamped-clamped beam resonator

This work presents a technique to cancel the parasitic feedthrough current in a fully CMOS integrated electrostatic micromechanical resonator. A four-electrode balanced topology has been proven to enhance the measured response of a polysilicon clamped-clamped beam resonator. The test results obtained show a pure RLC behavior of the resonator at 10.98MHz.

Virtual Game-Based Energy Balanced Topology Control Algorithm for Wireless Sensor Networks

In topology control (TC), game theory is an efficient approach to analyze the conflicting objectives of nodes to enable the topology with certain global properties in the presence of selfish nodes. But in many existing game-based TC algorithms, every node has to make others aware of its changes by transmitting the control information repeatedly, which results in much unnecessary energy waste and network lifetime reduction. To solve the problem, the concept of virtual game is introduced, which virtualizes the game process to avoid the repeated information exchange in the game process. In addition, considering that unbalanced distribution of energy consumption also restricts the network lifetime, a distributed Virtual Game-based Energy Balanced TC algorithm (VGEB) with incomplete information is proposed, which is mathematically analyzed. The analysis results show that the TC virtual game is a potential game and the virtual game algorithm can converge to the state of Nash Equilibrium, which is Pareto Optimal. Moreover, VGEB can easily construct the topology with a low information complexity of O(n) and the induced topology can maintain the network connectivity, where n is the number of nodes in network. Simulation results demonstrate that VGEB can effectively balance the nodes' energy consumption, greatly reduce the energy waste in the game process and has many other attractive topological features.

Analysis of a New 33–58-GHz Doubly Balanced Drain Mixer in 90-nm CMOS Technology

A new doubly balanced drain-pumped topology for CMOS passive mixer design is proposed in this paper. In the efforts to improve the conversion loss of passive balanced mixers, the CMOS drain-pumped topology is employed. In addition, the doubly balanced architecture with the advantages of good port-to- port isolations has been combined with the CMOS drain mixer de- sign. For the broad bandwidth and the flatness of the conversion loss, a wideband matching technique using a broadband Marchand balun network is analyzed and successfully implemented in the mixer design. This mixer is fabricated in standard 90-nm CMOS technology. According to experiment results, the mixer has a measured conversion loss of 7.5 ± 1.5 dB from 33 to 58 GHz. Based on the double-balanced architecture, the local oscillator (LO)-to-RF and LO-to-IF isolations are better than 42.7 and 51.5 dB, respectively. The mixer consumes zero dc power with a compact size of 0.55 × 0.52 mm2. To the best of our knowledge, this paper presents the first CMOS drain mixer using doubly balanced topology.

Relative formal topology: the binary positivity predicate comes first

In this paper we introduce relative formal topology so that we can deal constructively with the closed subsets of a topological space as well as with the open ones. In fact, within standard formal topology, the cover relation allows the definition of the formal opens, which are supposed to act as the formal counterparts of the open subsets, and within balanced formal topology, the binary positivity predicate allows the definition of the formal closed subsets, which are supposed to act as the formal counterparts of the closed subsets. However, these approaches are only fully satisfactory (according to the criterion introduced by the author in Valentini (2005)) if we can provide an adequate formalisation of the cover relation and the positivity predicate. But current formalisations fail in this respect since some intuitionistically valid relations between the open and closed subsets of a concrete topological space cannot be expressed. Our central result is that we can solve this problem through a generalisation of the standard cover relation together with a binary positivity predicate satisfying the positivity axiom.

Robust consensus of multiple inertial agents with coupling delays and variable topologies

AbstractIn this paper, we consider the exponential second‐order consensus problem of a network of inertial agents with time‐varying coupling delays and variable balanced topologies. The passive decomposition approach is employed to incorporate the agents' inertial effect into the distributed control design. The sufficient conditions for the exponential second‐order consensus are provided, both when the topology is switched arbitrarily (without dwell time between consecutive switches) and when it is switched with average dwell time. The results present conditions that must be satisfied by the controller design parameters and performance requirements. Furthermore, an approach to the design of consensus protocol is presented, which is robust to the time delays and the dynamically changing interaction topologies. Numerical examples are given to illustrate our theoretical results. Copyright © 2010 John Wiley & Sons, Ltd.

Collective tracking control for multi-agent system on balanced graphs

In this paper, we consider a collective tracking problem of a multi-agent system which has a varying-velocity leader and evolves on balanced information topologies. First, we propose a coordination-variable-based control strategy for every agent to track the leader whose state may not be measured. Moreover, from a collective behavior perspective, a new decomposition method is utilized to decompose the resulting closed-loop system into two subsystems, and a novel measure also is introduced to characterize collective tracking performance of the system. Finally, we prove that the proposed control strategy can not only estimate the tracking errors but also increase the introduced measure to improve collective tracking performance even under the case of balanced information topologies. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society