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Monitoring the condition of the aircraft actuators in various operating and environmental circumstances, this paper presents a method for measuring the surface roughness of aircraft actuators. The proposed method starts with the current and vibration signal as failure indicators and a dual-tree complex wavelet transformation (DTCWT) to generate the necessary features. Time-delay neural networks (TDNNs) have been developed for real-time performance monitoring to categorize problems and determine their severity. The simulation results show that the suggested method can accurately identify various faults. [ABSTRACT FROM AUTHOR]

To study the influence of different resistance lines and rows delay intervals on the shape of the muck pile and the throwing distance of open-pit bench blasting based on the open-pit bench blasting test, two-dimensional particle flow code (PFC2D) is used for numerical simulation. The experimental and simulation data were compared and analyzed, and the error value was acceptable. Meanwhile, different resistance lines and row delay intervals are used to conduct numerical simulation analysis. The results show that the height change of the muck pile is directly proportional to the resistance line, and the rock throwing distance is inversely proportional to the resistance line change. The best resistance line is 1.75 m in the actual working condition, according to the effect of the muck pile. By fitting the relationship between the resistance line and rock throwing distance and blasting muck pile's height, it is found that the relationship is nonlinear. By simulating different row delays, the optimal row delay time difference in the bench blasting model is determined to be 25 ms under similar working conditions. It provides a guiding significance for the blasting parameter design under similar working conditions. [ABSTRACT FROM AUTHOR]

In this article, a matched branch line‐loaded negative group delay (NGD) circuit without resistor is presented firstly, and then an Wilkinson power divider with NGD characteristic is implemented by integrating the NGD circuit and the power divider by using self‐packaged suspended coplanar waveguide (SCPW) technology. The self‐packaged SCPW power divider with NGD characteristic has been fabricated, and the design has been demonstrated by measurement, which indicates that the proposed power divider with NGD characteristic has a measured signal attenuation (S21) of 10.92 dB, a S11 attenuation of 32.1 dB, an NGD time of −2.42 ns, and an isolation of no less than 39 dB at the center frequency, while simple circuit topology, self‐packaging and compact circuit size have also been achieved. [ABSTRACT FROM AUTHOR]

The increase in the number of services in the power distribution grid leads to a massive increase in task data. Power distribution internet of things (PDIoT) is the specific application of internet of things (IoT) in the power distribution grid. By deploying a large number of PDIoT devices, the voltage, active power, reactive power, and harmonic parameters are collected to support distribution grid services such as fault identification and status detection. Therefore, PDIoT utilizes massive devices to collect and offload tasks to the edge server through 5G network for real-time data processing. However, how to dynamically select edge servers and channels to meet the energy-efficient and low-latency task offloading requirements of PDIoT devices still faces several technical challenges such as task offloading decisions coupling among devices, unobtainable global state information, as well as interrelation of various quality of service (QoS) metrics such as energy efficiency and delay. To this end, we firstly construct a joint optimization problem to maximize the weighted difference between energy efficiency and delay of devices in PDIoT. Then, the joint optimization problem is decomposed into a large-timescale server selection problem and a small-timescale channel selection problem. Next, we propose an ML-based two-stage task offloading algorithm, where the large-timescale problem is solved by two-side matching in the first stage, and the small-timescale problem is solved by adaptive ε -greedy learning in the second stage. Finally, simulation results show that compared with the task offloading delay-first matching algorithm and the matching theory-based task offloading strategy, the proposed algorithm performs superior in terms of energy efficiency and delay. [ABSTRACT FROM AUTHOR]

Summary: The extreme learning machine (ELM) is a single‐hidden layer feedforword neural network (FNN) without training hidden layer weights/biases. By constructing a recurrent extreme learning machine (Recurrent‐ELM) with time delay lines to model battery dynamic characteristics, a beetle antennae search based recursive least squares (BAS‐RLS) method is explored to online realize the state of charge (SOC) estimation. The contents include: (1) To decrease the computational burden, the ELM model with fixed hidden layer weights is adopted to model battery SOC, and a RLS algorithm is studied to online estimate SOC by using the sampled terminal voltages and currents; (2) To solve the modeling accuracy problem, a Recurrent‐ELM model with past/present voltages and currents, and past SOC as inputs is constructed by adding time delay lines to capture battery dynamic characteristics, so as to promote the battery modeling accuracy; (3) To determine suitable neuron numbers in the hidden layer, the BAS method is introduced to find the optimal neuron number in the hidden layer to promote intelligence of the Recurrent‐ELM based RLS algorithm. Simulation results indicate that the proposed model and method has high precision in SOC estimation compared with traditional method. [ABSTRACT FROM AUTHOR]

To cope with the challenge of successful edge offloading brought by the mobility of mobile devices in intelligent factories, this paper studies the optimization problem of the edge offloading strategy of mobile devices based on mobility. Considering the decision task flow executed by priority, the unique offloading mode of a single task, the communication range of the edge server, and the delay constraint of the offloading of a single task, appropriate computing resources are selected according to the real-time location of the mobile device to offload the computing task. Based on the edge computing architecture of an intelligent factory, this paper puts forward five different computation offloading methods. From a global perspective, the energy consumption and delay of tasks offloading in local, edge, cloud center, local-edge collaboration, and local-edge-cloud collaboration are considered. In this paper, the algorithm based on the genetic algorithm and particle swarm optimization is used to design and obtain the decision task flow offloading strategy with the lowest energy consumption and delay. Simulation results show that the proposed algorithm can reduce the computation offloading energy consumption and delay of mobile devices. [ABSTRACT FROM AUTHOR]

The progress of global economic integration has forced English learners to have an urgent need to improve their oral English. College students' oral English ability is currently the worst of the four abilities of listening, speaking, reading, and writing. The main reasons are internal and external. The internal reason is that the pronunciation characteristics of Chinese students are different from those of English. The external cause is that the practice environment and tools of oral English are not ideal, which affects the improvement of learners' oral English. This study proposes using a deep learning algorithm (DLA) English in the evaluation of oral English quality to improve learners' oral English level. The quality of oral English can be comprehensively evaluated in terms of pitch, speed of sound, and rhythm. The standard of pronunciation is the foundation of oral English and is the most critical factor. In many DLAs, the input unit of DNN at a certain moment and its upper and lower moment input units have no relationship and are independent of each other, and the timing dependencies of adjacent units are not fully considered. The results are generally not very good on speech recognition tasks. This study proposes a time-delay neural network (TDNN) and a long short-term memory (LSTM) network to calculate the posterior probability of the model state to model context-dependent features in order to solve this problem. The fusion model TDNN-LSTM is applied in the English spoken pronunciation recognition task. To compare the accuracy of oral English pronunciation, several classic DLAs are introduced. The experimental results show that the method described in this study has a number of advantages. Although the performance improvement of this method in terms of recognition accuracy is not large, a certain degree of improvement is also very important for the oral English teaching assistant system. [ABSTRACT FROM AUTHOR]

By deploying computing units in edge servers, the devicegenerated computation-intensive tasks can be offloaded from the cloud, lessening the core network's traffic and reducing the tasks' completion latency. To mitigate the burden on edge server and improve user experience, this paper proposes a deep reinforcement learning (DRL)- based multiuser multitask hybrid computing offloading model for offloading a set of computation-intensive tasks generated by multiple users to edge server and adjacent devices. The proposed model makes global computing offloading decisions for multiple computation-intensive tasks simultaneously rather than via one-by-one decisionmaking, which takes the impact of users' offloading decisions on the system's overall performance in multitask offloading scenarios into account. The main goal of this study is to reduce the long-term overall system delay. The model uses the recurrent neural network to extract the feature information of task and network state, improving the convergence speed and stability of the DRL model. The experimental results demonstrate that the global offloading decision-making model outperforms other methods regarding long-term overall system delay and device energy consumption. [ABSTRACT FROM AUTHOR]

It is very important for the safe operation of the power grid to be able to achieve real-time online monitoring, but along with the expansion of the smart grid, powerful computing power is required to achieve online monitoring, which cannot be loaded by ordinary servers. Due to the limited computing and storage resources of the server, it is difficult to fully meet the real-time requirements of online power line monitoring. Therefore, this research proposes a smart grid real-time monitoring and early warning system based on edge computing, which can reasonably allocate computing tasks according to the effective use of edge node resources. It can also collect and process information in real time, and can monitor the power grid online, which improves the fault identification efficiency of the power grid, effectively reduces the economic cost, and relieves the computing pressure of the online monitoring equipment on the cloud computing server. Meanwhile, considering the burst problem in allocation queue optimization, a multipriority allocation queue algorithm is proposed, and an improved greedy algorithm allocation model is used to solve the optimal scheduling problem between bursts. Simulation analysis shows that the scheduling scheme proposed in this paper can effectively reduce the monitoring delay of the power line monitoring system, improve the overall adaptability and compatibility of the system, meet the market demand, and facilitate promotion. [ABSTRACT FROM AUTHOR]

Large and complicated datasets may now be generated utilising device reading machine learning approaches, which can subsequently be used to model and study substances in a variety of ways, along with people who require robotics and automation. For data analysis, there was a delay in implementing device learning methodologies since nanomaterials have not yet achieved the overall benefits of automation. There has been an explosion in the number of tools available for learning about nanomaterials, but there are still significant roadblocks in the way of actually putting those tools to use in a practical way. The homes of nanoparticles can be examined and anticipated with the help of system learning algorithms, and this painting shows how classic and deep system mastery techniques may be done to preserve nanomaterials. Among the topics covered are the history of nanoprotection, as well as a forecast for the future of artificial intelligence's (AI) role in the field in the near future. [ABSTRACT FROM AUTHOR]

A reconfigurable negative group delay circuit (NGDC) with tunable group delay flatness is presented. The proposed NGDC is composed of an amplifier, three series resistors connecting with two transmission lines, two varactors, and a diode. By shorting different resistors through the diode, different negative group delay (NGD) times can be obtained. Two varactors are utilized to tune the flatness of the group delay. For verification, an NGDC is designed, fabricated, and measured at the center frequency of 1.0 GHz. The measured NGD time is tuned from −2.0 to −5.8 ns. The flat‐NGD bandwidth varies from 2.2% to 8.8% with ±8% group‐delay fluctuation. And the insertion loss varies from 6.5 to 13.8 dB. [ABSTRACT FROM AUTHOR]

A matched negative group delay (NGD) circuit with ultra‐low insertion loss by using self‐packaged multi‐layer suspended line is proposed. Two transmission paths with different electric‐lengths are used to produce positive phase slope, which would bring a negative group delay, while a coupled line is used for matching, and the commonly applied absorption resistors are not required. The NGD circuit has been fabricated and measured, and the design has been demonstrated with a measured NGD time of −2.84 ns, a NGD bandwidth of 34 MHz, a low insertion loss/signal attenuation (S21) of no more than 2.73 dB, and a S11 attenuation of about 27.8 dB. Both self‐packaging and metallized air cavities are used to reduce the wave leakage, and the multiple via holes usually used for electromagnetic shielding are saved, which greatly reduce the fabrication complexity. [ABSTRACT FROM AUTHOR]

A dual‐band dual circularly polarized (CP) patch antenna is proposed with low profile and small frequency ratio in this letter, which consists of a square patch, coupling lines, and a dual‐feed network with dispersive delay line. Noticing that this antenna is fabricated on a single‐layer substrate, thus acquiring low‐profile performance. As for the coupling scheme, the bandwidth of impedance matching is increased to achieve dual‐band radiation performance. On the premise that two orthogonal signals, which transmit in two paths of the dual‐feed network, provide equal magnitude, the circular polarization can be controlled by the corresponding phase difference. Benefited from the dispersive delay line, the requirements of quadrature phases are met to present left−/right‐handed circularly polarizations in two operating frequencies. Meanwhile, small frequency ratio can be easily achieved. To demonstrate the proposed design, the single‐layer antenna with a profile of 0.006λ0 is designed, fabricated and measured. The phase difference of two orthogonal signals is adjusted to −90° at the lower operating frequency 1.9 GHz to realize right‐handed CP characteristic, while 90° phase difference in two paths is achieved at the higher one 2.4 GHz to provide left‐handed CP characteristic. Measured results are found in reasonably a good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

Delay optimization has now emerged as an important optimization goal in logic synthesis. The delay optimization for ternary fixed polarity Reed–Muller (FPRM) circuits aims to find a ternary FPRM circuit with a minimum delay. Because the delay optimization for ternary FPRM circuits is a combinatorial optimization problem, in this paper, we first propose a multilevel adaptive quantum genetic algorithm (MAQGA), which divides individuals into three‐level populations: high‐level population, intermediate‐level population, and low‐level population and uses the proposed ternary quantum rotation gate, proposed ternary quantum correction gate, and proposed multi‐operator adaptive mutation mechanism to make the three‐level populations evolve. Moreover, based on the proposed delay decomposition strategy, we propose a delay optimization approach (DOA) for ternary FPRM circuits under the unit delay model, which searches for a ternary FPRM circuit with a minimum delay using the MAQGA. Experimental results demonstrated the effectiveness and superiority of the DOA in optimizing the delay of ternary FPRM circuits. [ABSTRACT FROM AUTHOR]

In this paper, the trajectory tracking control and the field programmable gate array (FPGA) implementation between a recurrent neural network with time delay and a chaotic system are presented. The tracking error is globally asymptotically stabilized by means of a control law generated from the Lyapunov–Krasovskii and Lur'e theory. The applicability of the approach is illustrated by considering two different chaotic systems: Liu chaotic system and Genesio–Tesi chaotic system. The numerical results have shown the effectiveness of obtained theoretical results. Finally, the theoretical results are implemented on an FPGA, confirming the feasibility of the synchronization scheme and showing that it is hardware realizable. [ABSTRACT FROM AUTHOR]

In this article, we propose a frequency discriminator (FD) design method to produce uniform frequency sub‐bands. FDs are designed using an interferometer projected with the proposed formulated phase. For experimental verification that a uniform sub‐band is formed using the proposed phase formula, 3‐bit FDs are designed and fabricated to operate in the 2 to 3 GHz and 2 to 4 GHz bands, respectively. The FD consists of a power divider/combiner, reference line, and delay line. Scattering parameters of the FDs are analyzed using RF simulation and measurement results. RF characteristic results show that a 3‐bit FD designed using the proposed phase formula can identify an unknown signal inside the defined frequency band. [ABSTRACT FROM AUTHOR]

In this paper, a design procedure for a linearly polarized ultra‐wide band (UWB) single layer reflectarray antenna (RA) is presented. The RA is comprised of novel unit cells of annular ring patches; each ring is connected to two phase delay lines to achieve a linear and smooth phase response over a wide frequency range. In the proposed RA, the designed true phase delay provides more than three cycles of 360°. By adjusting the length of these phase delay lines, a wide range of 1300° linear phase variation has been obtained over a wide frequency band. A wide bandwidth and low cross‐polarization (XP) levels were predicted using the utilized novel unit cell element and the elegant mirrored arrangement. To validate the simulated results, a prototype of circular aperture with 22.86 cm diameter was fabricated and its radiation patterns were measured. The measured 3‐dB gain bandwidth of the RA is 40%, and its maximum gain, aperture efficiency and XP levels are 19.3 dB, 69% and − 35 dB, respectively, which are in good agreement with simulation. [ABSTRACT FROM AUTHOR]

By deploying edge servers on the network edge, mobile edge computing network strengthens the real-time processing ability near the end devices and releases the huge load pressure of the core network. Considering the limited computing or storage resources on the edge server side, the workload allocation among edge servers for each Internet of Things (IoT) application affects the response time of the application's requests. Hence, when the access devices of the edge server are deployed intensively, the workload allocation becomes a key factor affecting the quality of user experience (QoE). To solve this problem, this paper proposes an edge workload allocation scheme, which uses application prediction (AP) algorithm to minimize response delay. This problem has been proved to be a NP hard problem. First, in the application prediction model, long short-term memory (LSTM) method is proposed to predict the tasks of future access devices. Second, based on the prediction results, the edge workload allocation is divided into two subproblems to solve, which are the task assignment subproblem and the resource allocation subproblem. Using historical execution data, we can solve the problem in linear time. The simulation results show that the proposed AP algorithm can effectively reduce the response delay of the device and the average completion time of the task sequence and approach the theoretical optimal allocation results. [ABSTRACT FROM AUTHOR]

A reconfigurable, planar, and end‐fire circularly polarized (CP) antenna with wide beamwidth is presented, which exhibits the bidirectional radiation with the same sense by combining two pairs of identical CP elements placed in a back‐to‐back configuration. The design of the element includes a meandering phase delay line, which connects a printed electric dipole and a quarter‐wavelength shorted microstrip patch. Then, eight p‐i‐n diodes are employed in the two dipoles arms to realize either left‐handed CP (LHCP) or right‐handed CP (RHCP) by manipulating the DC bias voltage across p‐i‐n. The prototype is designed to operate at a center frequency of 5.8 GHz with a size of 0.61 × 0.50 × 0.029 (λ03), where λ0 is the wavelength of the center frequency. Also, its end‐fire beam is in parallel with its plane. Experimental results show that the overlapped bandwidth for 10‐dB return loss and the 3‐dB axial ratio (AR) of the bidirectional end‐fire antenna is from 5.72 to 5.89 GHz for the two CP states. The half‐power beamwidth (HPBW) in the horizontal and vertical plane are 95°/115° at the 5.8 GHz. [ABSTRACT FROM AUTHOR]

A wideband negative group delay (NGD) microwave circuit with group delay flatness and bandwidth enhancement is proposed. The proposed negative group delay circuit (NGDC) is composed of a resistor connected by two transmission lines and a parallel branch consisted of a resistor linking with a stepped‐impedance transmission line and two open stubs. By tuning the characteristic impedance of the transmission lines, the flat‐NGD bandwidth is enhanced. For verification, an NGDC with a size of 0.24λg × 0.34λg is designed, fabricated, and measured. The measurement shows that an NGD time of −0.5 ns at the center frequency of 1.0 GHz is obtained with the NGD bandwidth of 68.6% over 0.668 to 1.365 GHz. Also, the flat‐NGD bandwidth reaches 46.3% or 0.776 to 1.243 GHz with ±8% group‐delay fluctuation while the insertion loss is less than 18.8 dB and return loss is greater than 21 dB. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate signal interference concept based wideband negative group delay (NGD) circuit with an arbitrary termination port impedance. The proposed circuit consists of unequal power division ratio 180° hybrid and in‐phase combiner. The NGD can be generated by controlling power division ratios of 180° hybrid and combiner. For experimental verification, the circuit is designed and fabricated at a center frequency of 2 GHz. The experiment results show that the proposed NGD circuit can provide 460 MHz NGD bandwidth (bandwidth of group delay <0 ns) with group delay of −0.8 ns at 2 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a multilayer recurrence network is introduced to examine the information linkage between carbon and energy markets. We first construct a multilayer recurrence network of energy and carbon markets, and we define the information linkage coefficient to measure the linkage relationship between the network layers based on the network microstructure. To measure the mutual leading relationship between carbon and energy markets, we construct a time-delay multilayer recurrence network and introduce the time-delay information linkage coefficient to measure the intersystem interaction. The carbon and energy prices, including West Texas Intermediate crude oil, coal, natural gas, and gasoline, from February 22, 2011, to April 1, 2019, are selected as sample data for empirical analysis. The results show that the linkage relationship between oil, coal, natural gas, and carbon prices presents a U-shaped trend in the second, transitional, and third phases of the European Union carbon market, while the linkage trend of gasoline and carbon prices continues to rise. The mutual leading relationship between energy and carbon prices changes in different stages, and carbon price plays a leading role at the present stage. [ABSTRACT FROM AUTHOR]

In this article, a novel planar reconfigurable circular polarization (CP) complementary antenna for unidirectional end‐fire radiation is proposed. Its radiator is the combination of a shorted quarter wavelength patch and an electric dipole, which provide the vertical and horizontal polarizations, respectively. By adding a 90° phase delay line, the proposed antenna radiates CP electromagnetic waves in the unidirectional end‐fire direction. Four p‐i‐n diodes are also inserted at joints of the electric dipole and the phase delay lines, and two orthogonal CP states, left‐hand (LH) and right‐hand (RH) CPs, can be switched. In order to reduce the number of DC bias lines, electric dipole arms on both sides of the substrate are connected by metal via‐holes, which simplifies the DC bias lines. The proposed antenna at 2.45 GHz is designed and fabricated. Its measured impedance bandwidth with |S11| < −10 dB and 3‐dB axial ratio bandwidth are 2.1% and 10.7%, respectively. Additionally, its maximum half power beamwidth in xoz plane is 196°. Reasonable agreement between the measured and simulated results validates the polarization reconfigurability of the proposed antenna. [ABSTRACT FROM AUTHOR]

A novel passive wireless integrated SAW-based antenna sensor for strain sensing is presented in this paper. A SAW delay line scheme is proposed for signal modulation, which could distinguish the backscattered data from environmental clutter in time domain. The theoretical relationship between the antenna resonance frequency shifts, the temperature, and the applied strain was established. A multiphysical coupled simulation process is proposed to improve the simulation accuracy. By comparing the phase shift of adjacent echoed data which is generated by SAW reflective grating, the temperature information could be extracted exactly and the effect of temperature fluctuation on the resonance frequency could be compensated. A more accurate passive (battery-free) wireless strain sensing could be provided by this proposed integrated antenna sensor than the previous proposed methods. Simulation and experimental results demonstrate the effectiveness of the sensor. [ABSTRACT FROM AUTHOR]

When the pumping operation of pumped storage unit suffers from power outage, the hydraulic transient poses a serious threat to the safe operation of the unit and its pressure pipeline system. For high-head pumped storage power station (PSPS), the water hammer pressure (WHP) and rotational speed rise ratio (RSRR) of each hydraulic unit will be increased during the pump outage condition. In order to limit the fluctuation of rotational speed and WHP in power-off condition, optimizing and choosing a reasonable guide vane closure scheme (GVCS) is an economic and efficient means to improve the dynamic characteristics of pumped storage unit. On the basis of the calculation model of the transition process of single tube-double unit type of a high-head PSPS, an optimization model of GVCS balancing WHP and RSRR objectives is established. Furthermore, the two-stage broken line and three-stage delayed GVCSs are applied to the pump outage condition, and the nondominated sorting genetic algorithm-II (NSGA-II) is introduced to calculate the optimal solution set under different water heads and different closure schemes. For four typical water heads, the multiobjective optimization results of the closure law show that the two-stage broken line law has a better Pareto front under high water head, while the three-stage delayed law has a better performance under low water head. Furthermore, through the results of transition process of typical schemes, the adaptability of GVCS and water head is analyzed. The method proposed in this paper can make the RSRR not more than −0.89, and the three-stage delayed law can even make the RSRR only −0.01. Methods of this paper provide a theoretical basis for optimum guide vane closure mode setting of PSPS. [ABSTRACT FROM AUTHOR]

In this paper, a comparative analysis of nanoscaled triple metal gate (TMG) recessed-source/drain (Re-S/D) fully depleted silicon-on-insulator (FD SOI) MOSFET has been presented for the design of the pseudo-NMOS inverter in the nanometer regime. For this, firstly, an analytical modeling of threshold voltage has been proposed in order to investigate the short channel immunity of the studied device and also verified against simulation results. In this structure, the novel concept of backchannel inversion has been utilized for the study of device performance. The threshold voltage has been analyzed by varying the parameters of the device like the ratio of metal gate length and the recessed-source/drain thickness for TMG Re-S/D SOI MOSFET. Drain-induced barrier lowering (DIBL) has also been explored in terms of recessed-source/drain thickness and the metal gate length ratio to examine short channel effects (SCEs). For the exact estimation of results, the comparison of the existing multimetal gate structures with TMG Re-S/D SOI MOSFET has also been taken under study in terms of electrostatic performance, i.e., threshold voltage, subthreshold slope, and on-off current ratio. These structures are investigated with the TCAD numerical simulator from Silvaco ATLAS. Furthermore, for the first time, TMG Re-S/D FD SOI MOSFET-based pseudo-NMOS inverter has been designed to observe the device performance at circuit levels. It has been found that the device offers high noise immunity with optimum switching characteristics, and the propagation delay of the studied circuit is recorded as 0.43 ps. [ABSTRACT FROM AUTHOR]

The occurrence of machining chatter may undermine the workpiece surface quality, accelerate the tool wear, and even result in serious damage to the machine tools. Consequently, it is of great importance to predict and eliminate the presence of such unstable and detrimental vibration. In this paper, we present an extended Adams-Moulton-based method for the stability prediction of milling processes with multiple delays. Taking the nonuniform pitch cutters or the tool runout into account, the regenerative chatter for milling operations can be formulated as delay differential equations with multiple delays. The dynamics model for milling regenerative chatter is rewritten in the state-space form. Dividing the spindle rotation period equally into small time intervals, the delay terms are approximated by Lagrange interpolation polynomials, and the Adams-Moulton method is adopted to construct the Floquet transition matrix. On this basis, the milling stability can be derived from the spectral radius of the transition matrix based on Floquet theory. The calculation efficiency and accuracy of the proposed algorithm are verified through making comparisons with the semidiscretization method (SDM) and the enhanced multistage homotopy perturbation method (EMHPM). The results show that the proposed method has both high computational efficiency and accuracy. [ABSTRACT FROM AUTHOR]

Machine-to-machine (M2M) communications allowmultiple devices to communicate directly without human intervention. There will be a huge number of devices in theM2M communications which results in enormous congestion in the current RandomAccess Channel (RACH) of LTE based cellular systems. This paper presents a protocol for improving the performance of the LTE RACH forM2M applications. This protocol, the Distributed Queuing Access for LTE (DQAL), is based on the Distributed Queuing (DQ) algorithm. One of the benefits of using that algorithmis minimizing the collision in the access phase for theM2Mcommunications. The reduction in the collision will turn in enhancing both the access success probability and the access delay for M2M devices (MDs). Furthermore, the protocol is designed to guarantee that the normal User Equipment (UE) device can access the system using the traditional RACH procedures without any modification. This will assure a seamless implementation of the proposed protocol over the existing LTE cellular systems. The simulation results show how the access delay obtained by the proposed DQAL protocol outperforms the Extended Access Baring (EAB) which is the baseline solution recommended by the 3 GPP for M2M communication. [ABSTRACT FROM AUTHOR]

We study the L2-gain analysis problem for a class of discrete-time switched systems with time-varying delays. A mode-dependent average dwell time (MDADT) approach is applied to analyze the L2-gain performance for these discrete-time switched delay systems. Combining a multiple Lyapunov functional method with the MDADT approach, sufficient conditions expressed in form of a set of feasible linear matrix inequalities (LMIs) are established to guarantee the L2-gain performance. Finally, a numerical example will be provided to demonstrate the validity and usefulness of the obtained results. [ABSTRACT FROM AUTHOR]

This paper deals with the performance evaluation and optimization of an efficient hybrid automatic repeat request (HARQ) scheme suitable for applications delivered over lossy multicast communication channels. In particular, different from previously investigated strategies, this paper proposes a modified HARQ scheme based on the symbol combining principle (MHARQ-SC) where multiple copies of a same packet are consecutively transmitted at each transmission opportunity. By considering as the performance metrics, the mean packet delivery delay, and the energy consumption per information packet, this paper presents suitable performance evaluation and optimization strategies tailored for multicast communications. For the sake of comparisons, it has been also analyzed, under the same operational conditions, the performance of different HARQ schemes optimized for multicast communications. Numerical results have been provided to validate the proposed performance evaluation and optimization approaches in the case of the MHARQ-SC scheme. An important result devised here is that the reported analytical results clearly highlight the performance gain of the proposed strategy in comparison with all the other considered alternatives. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper is concerned with the finite-time stability of Caputo fractional neural networks with distributed delay. The factors of such systems including Caputo's fractional derivative and distributed delay are taken into account synchronously. For the Caputo fractional neural network model, a finite-time stability criterion is established by using the theory of fractional calculus and generalized Gronwall-Bellman inequality approach. Both the proposed criterion and an illustrative example show that the stability performance of Caputo fractional distributed delay neural networks is dependent on the time delay and the order of Caputo's fractional derivative over a finite time. [ABSTRACT FROM AUTHOR]

We describe the architecture of a time-to-digital converter (TDC), specially intended to measure the delay resolution of a programmable delay line (PDL). The configuration, which consists of a ring oscillator, a frequency divider (FD), and a period measurement circuit (PMC), is implemented in a field programmable gate array (FPGA) device. The ring oscillator realized in loop containing a PDL and a look-up table (LUT) generates periodic oscillatory pulses. The FD amplifies the oscillatory period from nanosecond range to microsecond range. The time-to-digital conversion is based on counting the number of clock cycles between two consecutive pulses of the FD by the PMC. Experiments have been conducted to verify the performance of the TDC. The achieved relative errors for four PDLs are within 0.50%-1.21% and the TDC has an equivalent resolution of about 0.4 ps. [ABSTRACT FROM AUTHOR]

The paper introduces novel architectures for implementation of fully static master-slave flip-flops for low power, high performance, and high density. Based on the proposed structure, traditional C²MOS latch (tristate inverter/clocked inverter) based flip-flop is implemented with fewer transistors. The modified C²MOS based flip-flop designs mC²MOSff1 and mC²MOSff2 are realized using only sixteen transistors each while the number of clocked transistors is also reduced in case of mC²MOSff1. Postlayout simulations indicate that mC²MOSff1 flip-flop shows 12.4% improvement in PDAP (power-delay-area product) when compared with transmission gate flip-flop (TGFF) at 16X capacitive load which is considered to be the best design alternative among the conventional master-slave flip-flops. To validate the correct behaviour of the proposed design, an eight bit asynchronous counter is designed to layout level. LVS and parasitic extraction were carried out on Calibre, whereas layouts were implemented using IC station (Mentor Graphics). HSPICE simulations were used to characterize the transient response of the flip-flop designs in a 180 nm/1.8 V CMOS technology. Simulations were also performed at 130 nm, 90 nm, and 65 nm to reveal the scalability of both the designs at modern process nodes. [ABSTRACT FROM AUTHOR]

In this paper, we consider the applications of delay-tolerant networks (DTNs), where the nodes in a network are located in separated areas, and in each separated area, there exists (at least) an anchor node that provides regional network coverage for the nearby nodes. The anchor nodes are responsible for collecting and distributing messages for the nodes in the vicinity. This work proposes to use a set of messengers (named pigeons) that move around the network to deliver messages among multiple anchor nodes. Each source node (anchor node or Internet access point) owns multiple dedicated pigeons, and each pigeon takes a round trip starting from its home (i.e., the source) through the destination anchor nodes and then returns home, disseminating the messages on its way. We named this as a homing-pigeon-based messaging (HoPM) scheme. The HoPM scheme is different from the prior schemes in that each messenger is completely dedicated to its home node for providing messaging service. We obtained the average message delay of HoPM scheme in DTN through theoretical analysis with three different pigeon scheduling schemes. The analytical model was validated by simulations. We also studied the effects of several key parameters on the system performance and compared the results with previous solutions. The results allowed us to better understand the impacts of different scheduling schemes on the system performance of HoPM and demonstrated that our proposed scheme outperforms the previous ones. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

By using an integral inequality, we establish some sufficient conditions for the existence and p-exponential stability of periodic solutions for a class of impulsive stochastic BAM neural networks with time-varying delays in leakage terms. Moreover, we present an example to illustrate the feasibility of our results. [ABSTRACT FROM AUTHOR]

This paper studies a class of periodic n species cooperative Lotka-Volterra systems with continuous time delays and feedback controls. Based on the continuation theorem of the coincidence degree theory developed by Gaines and Mawhin, some new sufficient conditions on the existence of positive periodic solutions are established. [ABSTRACT FROM AUTHOR]

We consider the following generalized n-species Lotka-Volterra type and Gilpin-Ayala type competition systems with multiple delays and impulses: x'i(t) = xi(t) [ai(t) - bi(t)xi(t) - Σnj=1 Ci j(t)xαijj (t-pi j(t)) - Σnj=1 dij(t)xᵦij j (t - τi j(t)) - Σnj=1 ei j(t) ∫0-952;ij kij(s)x ϒijj (t + s)ds - Σn j=1 fij (t) ∫0-ϑij Kij(ξ)xiδij (t +ξ)xjσij (t + ξ)dξ], a.e,t > 0, t ≠ tk; xi(tk+) - xi(tk-) = hikxi(tk), i = 1,2,...,n,k ∈ Z+. By applying the Krasnoselskii fixed-point theorem in a cone of Banach space, we derive some verifiable necessary and sufficient conditions for the existence of positive periodic solutions of the previously mentioned. As applications, some special cases of the previous system are examined and some earlier results are extended and improved. [ABSTRACT FROM AUTHOR]

We use the fixed point theory to investigate the qualitative analysis of a nonlinear delay dynamic equation on an arbitrary time scales. We illustrate our results by applying them to various kind of time scales. [ABSTRACT FROM AUTHOR]

A network of coupled limit cycle oscillators with delayed interactions is considered. The parameters characterizing the oscillator's frequency and limit cycle are allowed to self-adapt. Adaptation is due to time-delayed state variables that mutually interact via a net-work. The self-adaptive mechanisms ultimately drive all coupled oscillators to a consensual cyclostationary state, where the values of the parameters are identical for all local systems. They are analytically expressible. The interplay between the spectral properties of the coupling matrix and the time delays determines the conditions for which convergence towards a consensual state takes place. Once reached, this consensual state subsists even if interactions are removed. In our class of models, the consensual values of the parameters depend neither on the delays nor on the network's topologies. [ABSTRACT FROM AUTHOR]

Tracking control of nonlinear systems with significant delay effects has been the focus of intensive research. In this paper, we propose an effective supervised adaptive control scheme to tackle the problem. The scheme is composed of an adaptive control part of two neuron-like models with delay effects and a supervisory control part to enhance robustness against disturbance and model uncertainties. A design methodology based on the Lyapunov analysis is presented. Experimental results obtained from a practical temperature control system show that not only is the design procedure conceptually simple but also the control performance is also excellent when compared with the traditional PD controller. Also, the feedforward term is able to provide extra improvement in the regulation performance. [ABSTRACT FROM AUTHOR]

In the paper are presented the expressions for all network functions of common-ground, uniformpassive ladders having, in general, complex terminations at both their ends. The Elmore's delay and rise times calculated for selected types of RLC ladders have indicated their slight deviation from delay and rise times obtained according to their classical definitions. For common-ground, integrating type RC ladder with voltage-step input, the Elmore's delay- and rise-times are produced in closed-form, both for ladder nodes and points. Furthermore, it is proposed a particular common-ground, uniform RLC ladder being amenable to application as delay line for pulsed and analog input signals. For this ladder, the Elmore's delay and rise times relating to their node voltages are produced in a closed-form, enabling thus with the realization of artificial (a) pulse delay line with arbitrarily and independently specified overall Elmore's delay and rise times and (b) true delay line with arbitrarily specified delay time for frequency bounded analog and/or pulsed input signals. In cases (a) and (b), precise procedures are formulated for calculation of ladder length and of all its RLC parameters. The obtained results are illustrated with several practical examples and are, also, verified through pspice simulation. [ABSTRACT FROM AUTHOR]

This paper is concerned with the network-based fault detection problem for a class of nonlinear discrete-time networked control systems with multiple communication delays and bounded disturbances. First, a sliding mode based nonlinear discrete observer is proposed. Then the sufficient conditions of slidingmotion asymptotical stability are derived by means of the linear matrix inequality (LMI) approach on a designed surface. Then a discrete-time sliding-mode fault observer is designed that is capable of guaranteeing the discrete-time sliding-mode reaching condition of the specified sliding surface. Finally, an illustrative example is provided to show the usefulness and effectiveness of the proposed design method. [ABSTRACT FROM AUTHOR]

As the distribution of clock signals between the nodes of a network became a critical operational requisite, the transmission delays have to be studied because they affect the accurate recovering of the time basis. In this work, the critical delay value is calculated considering simplifications compatible with practical situations. The main contribution is to consider the dissipative terms in the node equations, expressing critical delays, depending on the time constant of the dissipation. [ABSTRACT FROM AUTHOR]

This paper proposes a non-wide-sense-stationary-uncorrelated scattering (WSSUS) channel model for vehicle-to-vehicle (V2V) communication systems. The proposed channel model is based on the tapped-delay line (TDL) structure and considers the correlation between taps both in amplitude and phase. Using the relationship between the correlation coefficients of complex Gaussian, Weibull, and Uniform random variables (RVs), the amplitude and the phase of taps with different delays are modeled as correlated RVs to reflect the non-WSSUS properties of V2V channels. The effectiveness of the proposed channel model and simulation method is validated by the measurements in different scenarios. [ABSTRACT FROM AUTHOR]

Constructing a new Lyapunov functional and employing inequality technique, the existence, uniqueness, and global exponential stability of the periodic oscillatory solution are investigated for a class of fuzzy bidirectional associative memory (BAM) neural networks with distributed delays and diffusion. We obtained some sufficient conditions ensuring the existence, uniqueness, and global exponential stability of the periodic solution. The results remove the usual assumption that the activation functions are differentiable. An example is provided to show the effectiveness of our results. [ABSTRACT FROM AUTHOR]

For the purpose of dynamic systems modeling, it was proposed to include feedback connections or delay elements in the classical feed-forward neural network structure so that the present output of the neural network depends on its previous values. These delay elements can be connected to the hidden and/or output neurons of the main neural network. Each delay element gets a value of a state variable at a past time instant and keeps this value during a single sampling period. The groups of delay elements record the values of the state variables for a given time period in the past. Changing the number of the delay elements, which belongs to one group, a shorter or a longer time period in the past can be accounted for. Thus, the connection weights determine the influence of the past process states on the present state in a similar way as it is in the time delay kernel or cause-effect relation membership function (CER-MF) models. Specific feed-forward neural networks with time delay connections are used to solve the problem of neural network chemostat modeling as well as specific kinetic rates modeling. The weights of the feedback connections obtained during model training are discussed as the points of a time delay kernel or as the strength levels in a CER model (the points in the CER-MF). The corresponding changes in these weights with the changing time period in the past are shown. © 2004 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This paper presents the considerations on selecting a multiprocessor MISD architecture for fast implementation of the vision image processing. Using the author's earlier experience with real-time systems, implementing of specialized hardware processors based on the programmable FPGA systems has been proposed in the pipeline architecture. In particular, the following processors are presented: median filter and morphological processor. The structure of a universal reconfigurable processor developed has been proposed as well. Experimental results are presented as delays on LCA level implementation for median filter,morphological processor, convolution processor, look-up-table processor, logic processor and histogram processor. These times compare with delays in general purpose processor and DSP processor. [ABSTRACT FROM AUTHOR]

A simple algorithm is proposed for reconstruction of parametrized families of chaotic dynamics. This algorithm enables one to generate bifurcation diagrams which are qualitatively the same as the original ones only from several time-waveforms, without knowing an explicit form of the dynamics and information of the parameter values. The algorithm consists of two steps. First, globally smooth nonlinear predictors are computed for all time waveforms. Second, the Karhunen-Loéve transform is used to find only significant parameters contributing to the bifurcations. The algorithm is tested against two parametrized families of dynamics: the Hénon family and the coupled logistic/delayed-logistic family. © 1997 John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

A compact self‐matched negative group delay circuit (NGDC) with tunable center frequency and tunable group delay (GD) is proposed. Two varactors and a variable resistor are utilized to implement the tunability of the center frequency and GD of the proposed NGDC. To verify the design concept, a tunable NGDC is designed and fabricated. The measured center frequency is tuned from 0.8 to 1.3 GHz and the measured NGD time is tuned from −1 to −10 ns. The insertion loss varies from 16.0 to 34.5 dB. In the process of tuning the center frequency and NGD time, the return losses keep better than 30 dB. [ABSTRACT FROM AUTHOR]

In this communication a 2 × 2 dielectric resonator antenna (DRA) array is proposed with a wideband frequency response. An air bridgeless coplanar waveguide (CPW) power divider network is first time used to feed the 2 × 2 DRA array. Four rectangular DRAs are used as array element and exited in TE111 mode by four slots at the end of the CPW lines in the feed network. The straight CPW phase delay line in feed network is further meandered resulting an enhanced radiation performance. The proposed DRA array exhibits a wideband response with an impedance bandwidth of 16% while maintaining a stable broadside radiation pattern with the gain range from 8 to 9.4 dBi. The proposed design is fabricated and measured, reaching good agreement with simulation results. [ABSTRACT FROM AUTHOR]