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This paper discusses the various aspects involving the research and development of smart grids. Discussed are applications, from large grid renewable integration, wide-area monitoring, protection, and control systems to microgrids. Load scheduling and power balance, communications issues, understanding customer behavior, large-area protection, and distribution control are only some aspects of the challenge of making power grids more robust and more intelligent. The potential complexity of such smart grids requires careful study and analysis before actual realization. This paper explains how such challenges are addressed using real-time simulation technologies in different laboratories around the world. [ABSTRACT FROM AUTHOR]

Quantum key distribution (QKD) relies on the laws of physics to establish a symmetric binary key between remote parties. A QKD link involves the realization of a quantum channel for the transmission of quantum key material encoded in certain photon properties, as well as a public channel for verification of the exchanged key material. This paper deals with the mutual dependence of these channels and analyzes the impact of performance of both channels on the overall key material establishment process. This paper presents measurement data obtained under laboratory conditions as well as the results obtained by establishing a virtual QKD link. Despite the common beliefs that increased quantum bit error rate implies a larger amount of traffic on the public channel, our measurements prove the opposite. The obtained data clearly show that the public channel has a major impact on the overall performance of the QKD link. [ABSTRACT FROM PUBLISHER]

Besides designing channel-hopping (CH) sequences, finding good methods of communication rendezvous is important for improving spectral efficiency and alleviating traffic load of cognitive radio (CR) networks. In this paper, new asynchronous-symmetric CH sequences are constructed and their (channel overlap, even-channel-use, and pairwise shift invariance) properties are investigated. Their operations in three transmission scenarios involving different basic collision-avoidance mechanisms are analyzed and compared in terms of maximum time-to-rendezvous, rendezvous-success (RS) rate, and RS variance. This paper shows that the new sequences have shorter period, larger cardinality, and smaller RS variations than other CH sequences, thus supporting greater number of secondary users and more frequent and uniform rendezvous in the CR networks. [ABSTRACT FROM PUBLISHER]

This paper surveys the literature over the last decades in the field of self-organizing multiagent systems. Self-organization has been extensively studied and applied in multiagent systems and other fields, e.g., sensor networks and grid systems. Self-organization mechanisms in other fields have been thoroughly surveyed. However, there has not been a survey of self-organization mechanisms developed for use in multiagent systems. In this paper, we provide a survey of existing literature on self-organization mechanisms in multiagent systems. We also highlight the future work on key research issues in multiagent systems. This paper can serve as a guide and a starting point for anyone who will conduct research on self-organization in multiagent systems. Also, this paper complements existing survey studies on self-organization in multiagent systems. [ABSTRACT FROM PUBLISHER]

Population dynamics have been widely used in the design of learning and control systems for networked engineering applications, where the information dependency among elements of the network has become a relevant issue. Classic population dynamics (e.g., replicator, logit choice, Smith, and projection) require full information to evolve to the solution (Nash equilibrium). The main reason is that classic population dynamics are deduced by assuming well-mixed populations, which limits the applications where this theory can be implemented. In this paper, we extend the concept of population dynamics for nonwell-mixed populations in order to deal with distributed information structures that are characterized by noncomplete graphs. Although the distributed population dynamics proposed in this paper use partial information, they preserve similar characteristics and properties of their classic counterpart. Specifically, we prove mass conservation and convergence to Nash equilibrium. To illustrate the performance of the proposed dynamics, we show some applications in the solution of optimization problems, classic games, and the design of distributed controllers. [ABSTRACT FROM PUBLISHER]

In this paper, we investigate the simultaneous wireless information and power transfer in a multiple-input multiple-output decode-and-forward relay system, where the relay is an energy harvesting (EH) multi-antenna node equipped with an EH receiver and an information decoding (ID) receiver. The relay harvests the energy from the radio frequency signals sent by the source and uses it to forward the signals to the destination. The main objective in this paper is to maximize the achievable transmission rate of the overall link by optimizing the source/relay precoders. First, we study an upper bound on the maximum achievable rate where we assume that the EH and ID receivers operate simultaneously and have access to the whole power of the received signals. Afterward, we study two practical schemes, which are the power splitting and time switching schemes, where the ID and EH receivers have partial access to the power or duration of the received signals. For each scheme, we have studied the complexity and the performance comparison. In addition, we considered the case of the imperfect channel estimation error and we have observed its impact on the achievable end-to-end rate and the harvested energy at the relay. [ABSTRACT FROM PUBLISHER]

Vehicle-to-vehicle (V2V) communication plays a pivotal role in intelligent transport systems (ITS) with cellular-vehicle to everything (C-V2X) and IEEE 802.11p being the two competing enabling technologies. This paper presents multi-dimensional discrete-time Markov chain (DTMC) based models to study the medium access control (MAC) layer performance of the IEEE 802.11p standard and C-V2X Mode 4, considering periodic cooperative awareness messages (CAMs) and event-driven decentralized environmental notification messages (DENMs). Closed-form solutions for the steady-state probabilities of the models are obtained, which are then utilized to derive expressions for several key performance metrics. Numerical results are provided to draw insights on the performance. In particular, a performance comparison between IEEE 802.11p and C-V2X Mode 4 in terms of the average delay, the collision probability, and the channel utilization is presented. The results show that IEEE 802.11p is superior in terms of average delay, whereas C-V2X Mode 4 excels in collision resolution. The paper also includes design insights on possible future MAC layer performance enhancements of both standards. [ABSTRACT FROM AUTHOR]

Existing microgrid communication relies on classical public key systems, which are vulnerable to attacks from quantum computers. This paper uses quantum key distribution (QKD) to solve these quantum-era microgrid challenges. Specifically, this paper makes the following novel contributions: 1) it devises a novel QKD simulator capable of simulating QKD protocols; 2) it offers a QKD-based microgrid communication architecture for microgrids; 3) it shows how to build a quantum-secure microgrid testbed in an RTDS environment; 4) it develops a key pool sharing (KPS) strategy to improve the cyberattack resilience of the QKD-based microgrid; and 5) it analyzes the impacts of critical QKD parameters with the testbed. Test results provide insightful resources for building a quantum-secure microgrid. [ABSTRACT FROM AUTHOR]

This paper investigates the event-triggered consensus of linear multiagent systems with periodic data sampling mechanisms, where random packet losses are taken into account. The random packet losses occur in communication links based on a certain probability, and it is subject to the Bernoulli distribution. A novel distributed control protocol is designed based on the combined measurement to achieve the mean square consensus. By using the Riccati inequalities and linear matrix inequalities, an event-triggered condition with fewer parameters is also designed to reduce the information updating number. The interaction among the control gain matrix, sampling interval, and packet losses probability is used to describe the consensus conditions. The maximum sampling interval is presented explicitly. It is shown that the advantages of the proposed event-triggered strategy with the data sampling mechanism can avoid the Zeno behavior of the systems and continuous monitoring of the states. The simulations are provided to verify the proposed control strategy. [ABSTRACT FROM AUTHOR]

This paper studies quasi-synchronization in networked heterogeneous harmonic oscillators. By introducing a leader, two distributed synchronization protocols are first proposed for heterogeneous networks by utilizing continuous real-time information and aperiodic sampled-data information. Then, the sufficient conditions on quasi-synchronization are established for heterogeneous networks coupled with nonidentical harmonic oscillators. It is found that each follower oscillator can converge to a bounded region of the leader by adopting either a continuous-time protocol or sampled-data protocol. The upper bound of the region is solved for networked heterogeneous harmonic oscillators. Finally, an electrical network is provided to illustrate the applicability of the theoretical results, and two examples are provided to illustrate the effectiveness of the sufficient criteria. [ABSTRACT FROM AUTHOR]

This paper is concerned with the fixed-time cooperative relay tracking control problem for a set of planar agents in a surveillance network. The plane is partitioned into multiple “capture regions” by using the Voronoi partition according to agents’ positions. Once an evader enters into a new capture region, one agent of the tracer team stops and the tracking mission is relayed to another one who is in charge of the new region. As a result, an impulsive model is proposed to describe the problem and a distributed fixed-time cooperative relay control strategy is provided that is not dependent on initial condition. Numerical simulations are provided to demonstrate the validness of the cooperative relay tracking scheme. [ABSTRACT FROM AUTHOR]

Intelligent reflecting surface (IRS) has emerged as a promising technique to enhance wireless communication performance cost-effectively. The existing literature has mainly considered IRS being deployed near user terminals to improve their performance. However, this approach may incur a high cost if IRSs need to be densely deployed in the network to cater to random user locations. To avoid such high deployment cost, in this paper we consider a new IRS aided wireless network architecture, where IRSs are deployed in the vicinity of each base station (BS) to assist in its communications with distributed users regardless of their locations. Besides significantly enhancing IRSs’ signal coverage, this scheme helps reduce the IRS-associated channel estimation overhead as compared to conventional user-side IRSs, by exploiting the nearly static BS-IRS channels over short distance. For this scheme, we propose a new two-stage transmission protocol to achieve IRS channel estimation and reflection optimization for uplink data transmission efficiently. In addition, we propose effective methods for solving the user-IRS association problem based on long-term/statistical channel knowledge and the selected user-IRS-BS cascaded channel estimation problem. Finally, all IRSs’ passive reflections are jointly optimized with the BS’s multi-antenna receive combining to maximize the minimum achievable rate among all users for data transmission. Numerical results show that the proposed co-site-IRS empowered BS scheme can achieve significant performance gains over the conventional BS without co-site IRS and existing schemes for IRS channel estimation and reflection optimization, thus enabling an appealing low-cost and high-performance BS design for future wireless networks. [ABSTRACT FROM AUTHOR]

The rejection rates of upper-limb prosthetic devices in adults are high, currently averaging 26% and 23% for body-powered and electric devices, respectively. While many factors influence acceptance, prosthesis training methods relying on novel virtual reality systems have been cited as a critical factor capable of increasing the likelihood of long-term, full-time use. Despite that, these implementations have not yet garnered widespread traction in the clinical setting, and their use remains immaterial. This review aims to explore the reasons behind this situation by identifying trends in existing research that seek to advance Extended Reality “X-Reality” systems for the sake of upper-limb prosthesis rehabilitation and, secondly, analyzing barriers and presenting potential pathways to deployment for successful adoption in the future. The search yielded 42 research papers that were divided into two categories. The first category included articles that focused on the technical aspect of virtual prosthesis training. Articles in the second category utilize user evaluation procedures to ensure applicability in a clinical environment. The review showed that 75% of articles that conducted whole system testing experimented with non-immersive virtual systems. Furthermore, there is a shortage of experiments performed with amputee subjects. From the large-scale studies analyzed, 71% of those recruited solely non-disabled participants. This paper shows that X-Reality technologies for prosthesis rehabilitation of upper-limb amputees carry significant benefits. Nevertheless, much still must be done so that the technology reaches widespread clinical use. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicle (UAV)-based streaming media transmission may become unstable when the bit rate generated by the source load exceeds the channel capacity owing to the UAV location and speed change. The change of the location can affect the network connection, leading to reduced transmission rate; the change of the flying speed can increase the video payload due to more I-frames. To improve the transmission reliability, in this paper we design a Client-Server-Ground&User (C-S-G&U) framework, and propose an algorithm of splitting-merging stream (SMS) for multi-link concurrent transmission. We also establish multiple transport links and configure the routing rules for the cross-layer design. The multi-link transmission can achieve higher throughput and significantly smaller end-to-end delay than a single-link especially in a heavy load situation. The audio and video data are packaged into the payload by the Real-time Transport Protocol (RTP) before being transmitted over the User Datagram Protocol (UDP). The forward error correction (FEC) algorithm is implemented to promote the reliability of the UDP transmission, and an encryption algorithm to enhance security. In addition, we propose a Quality of Service (QoS) strategy so that the server and the user can control the UAV to adapt its transmission mode dynamically, according to the load, delay, and packet loss. Our design has been implemented on an engineering platform, whose efficacy has been verified through comprehensive experiments. [ABSTRACT FROM AUTHOR]

The work presented in this paper describes a multi-issue negotiation protocol between active consumers and a management platform in order to establish load coordination in a highly congested network. The multi-issue negotiation protocol considers simultaneously the consumption interval, the price, and the size of the energy packages, which is the main contribution of this work. Regarding the implementation methodology, the proposed algorithms have been implemented using MATLAB classes that allow emulating the behaviour of a multi-agent system in which each vehicle is an agent that interacts with the platform, which is another agent. In the present work, and without loss of generality, the algorithm is applied to coordinate the charging of electric vehicles (EVs) in a distribution network in which building loads represent critical loads. The algorithm is tested in a realistic environment, and its stability and performance are evaluated. Furthermore, the description of the algorithm is provided in a generic form, and it could be applied to any other scenario. [ABSTRACT FROM AUTHOR]

This paper provides a summary of media distribution in the 3GPP 5G System. We provide a status overview on the basics of 5G and in particular the Release 16 technologies on 5G Media Streaming and 5G Broadcast. Particular focus in this document are the recent Release-17 activities including extensions to 5G Media Streaming and 5G Broadcast. On the former, for example the integration of edge computing into media streaming is a major focus. On the latter, 5G Broadcast is extended to support co-existence of the technology with other broadcast technologies in the UHF band. A new set of functionalities is developed under the 5G Multicast–Broadcast Services (5MBS) umbrella work item. This includes new user service and system architecture functions to support broadcast and multicast throughout the 5G system. Particular focus in this paper are the radio layer and physical layer extensions to support point-to-multipoint delivery on top of New Radio (NR). We also touch briefly on the relevance of the 5G media distribution for third party ecosystems and industry with special focus on collaboration of media verticals and the 5G ecosystem. [ABSTRACT FROM AUTHOR]

The state estimation problem of heterogeneous multi-agent systems with random transport protocol is investigated in this paper. Due to the dependency of the agent dynamics and the random sparse structure induced by the random transport protocol, the optimal state estimation design becomes complex and challenging. An optimal state estimator is successfully designed by the Hadamard product and gradient method. Based on the analysis of the matrix functions, a sufficient condition is established to guarantee that the average estimate error covariance is limited. Finally, a numerical example and a smart grid model are utilized to demonstrate the effectiveness of the deigned estimator. [ABSTRACT FROM AUTHOR]

This paper investigates the exponential synchronization of coupled Lur’e dynamical networks with multiple time-varying delays and derivative coupling. In order to synchronize the Lur’e dynamical networks to the corresponding Lur’e systems, we propose a kind of impulsive pinning control strategy, where different functions of impulsive effects are taken into account. Sufficient conditions are derived for the exponential synchronization of the derivative coupled Lur’e dynamical networks by jointly applying the contradiction proof method, the concept of an average impulsive interval, comparison principle, and the extended parameters variation formula. Simultaneously, the convergence rates of exponential synchronization are obtained according to the definition of the impulsive solution equation on different functions of impulsive effects. Furthermore, three numerical examples are presented to demonstrate the validity of the theoretical analysis and the control protocol. [ABSTRACT FROM AUTHOR]

In this paper, the scaling law of the network throughput of a special type of heterogeneous networks is studied, where a secondary network composed of cognitive users shares the same resources opportunistically with a primary network of licensed users. Some pioneering works in this area showed that this type of heterogeneous networks performs as well as two stand-alone networks under the dense network model. A key assumption behind this conclusion is that the density of the secondary network is higher than that of the primary network in the order sense, which essentially decouples the two overlaid networks as the secondary network dominates asymptotically. In this paper, we endeavor to investigate this problem with a weaker condition that the dimensions of the two overlaid networks are on the same order, under the extended network model. Our analysis shows that, with the ratio of the two network sizes larger than a threshold, this weaker (and arguably more practical) condition does not degrade either network throughput scaling. Our result further reveals the potential of cognitive radio (CR) technology in real applications. [ABSTRACT FROM PUBLISHER]

This paper presents the overall framework for high-performance vehicle streams that integrates the transportation and the communication layered architectures together. It shows the process in establishing an infrastructure for high-performance vehicles and the theoretical development and deployment of cooperative adaptive cruise control (CACC) for heterogeneous vehicles that is integrated with lateral control. The system is designed to be fault tolerant and uses the concept of subplatoons. Our framework is based on integrating a transportation layered architecture with the Wireless Access in Vehicular Environment (WAVE) communication protocol. [ABSTRACT FROM PUBLISHER]

Assuming noisy feedback channels, this paper investigates the data transmission efficiency and robustness of different automatic repeat request (ARQ) schemes using adaptive power allocation. Considering different block-fading channel assumptions, the long-term throughput, the delay-limited throughput, the outage probability, and the feedback load of different ARQ protocols are studied. A closed-form expression for the power-limited throughput optimization problem is obtained, which is valid for different ARQ protocols and feedback channel conditions. Furthermore, the paper presents numerical investigations on the robustness of different ARQ protocols to feedback errors. It is shown that many analytical assertions about the ARQ protocols are valid both when the channel remains fixed during all retransmission rounds and when it (in)dependently changes in each round. As demonstrated, optimal power allocation is crucial for the performance of noisy ARQ schemes when the goal is to minimize the outage probability. [ABSTRACT FROM PUBLISHER]

In this paper, the leader-following consensus problem of multiagent systems with general dynamics under event-triggered mechanisms is investigated. A centralized event-triggered mechanism (CEM) is first proposed. Then, a distributed dynamic event-triggered mechanism is developed by introducing an internal variable. In the CEM case, each agent uses global information of the multiagent system, while in the distributed case, each agent only uses local information of its own and its neighbors. The multiagent system can achieve asymptotic consensus as well as exclude the Zeno phenomenon under the designed event-triggered rules in both cases. A multiagent system consisting of interconnected pendulums is provided to demonstrate the merits and correctness of the proposed methods. [ABSTRACT FROM AUTHOR]

Vehicular ad hoc networks (VANETs) are wireless self-organizing networks, whose communication is conducted through open wireless channels, thus making it vulnerable to various attacks. It is therefore necessary to employ encryption technology to ensure secure communication. In view of the foregoing, key agreement techniques are introduced to VANET communications. The group key agreement (GKA) protocol allows a group of participants to establish a public session key for a secure communication channel over an insecure network. The traditional GKA protocol is inefficient, however, and consumes considerable amounts of resources. With the aim of resolving problems related to information security and privacy preservation in VANETs, this paper proposes a full session key agreement scheme based on chaos mapping. In this paper, the first phase describes the key agreement between the fog server and group administrator; the second phase describes the group key agreement for vehicle nodes in the group where the vehicle can only communicate with vehicles having the same group key without the aid of a trusted key center or centralized key distributor. The proposed scheme is based on Chebyshev chaotic mapping algorithm, in which a chaotic map is utilized to provide a one-way hash; Chebyshev polynomial is also employed to establish a public multi-party key; it avoids the modular multiplication index or scalar multiplication on the elliptic curve. The proposed scheme does not only satisfy the security requirements in VANETs but also performs detailed analysis. [ABSTRACT FROM AUTHOR]

In this paper we propose a two-way protocol of physical layer security using the method of privacy amplification against eavesdroppers. First we justify our proposed protocol by analyzing the physical layer security provided by the classic wiretap channel model (i.e. one-way protocol). In the Gaussian channels, the classic one-way protocol requires Eve’s channel to be degraded w.r.t. Bob’s channel. However, this channel degradation condition depends on Eve’s location and whether Eve’s receiving antenna is more powerful than Bob’s. To overcome this limitation, we introduce a two-way protocol inspired in IEEE TIT (1993) that eliminates the channel degradation condition. In the proposed two-way protocol, on a first phase, via Gaussian channel, Bob sends randomness to Alice, which is partially leaked to Eve. Then, on a second phase, Alice transmits information to Bob over a public noiseless channel. We derive the secrecy capacity of the two-way protocol when the channel to Eve is also Gaussian. We show that the capacity of the two-way protocol is always positive. We present numerical values of the capacities illustrating the gains obtained by our proposed protocol. We apply our result to simple yet realistic models of satellite communication channels. [ABSTRACT FROM AUTHOR]

This paper considers leader-following bipartite consensus of single-integrator multiagent systems in the presence of measurement noise. To attenuate the noise, a time-varying consensus gain ${q}$ (${t}$) is introduced into the stochastic approximation-type protocol. Necessary and sufficient conditions for ensuring a strong mean square leader-following bipartite consensus are given. In particular, in the absence of measurement noise, the convergence speed of error dynamics is dependent on the eigenvalues of Laplacian and the rate of ${\int ^{{t}}_{0}{q}({s})\text {d}{s}}$ approaching infinity. By appropriately choosing ${q}$ (${t}$), the speed of leader-following bipartite consensus convergence can be improved in a fixed communication topology. It is proven that conditions for the signed digraph to be structurally balanced and having a spanning tree are necessary and sufficient to ensure leader-following bipartite consensus, regardless of measurement noise. [ABSTRACT FROM AUTHOR]

This paper considers the consensus control problem of heterogeneous linear multiagent systems. A distributed proportional–integral (PI) protocol is presented to ensure consensus of heterogeneous linear multiagent systems with directed communication graphs. Sufficient conditions for the choice of control parameters are derived. For the case that the agents are subject to the external time-varying but bounded disturbances, the proposed distributed PI protocol can assure uniformly ultimate boundedness of the consensus error. The effectiveness of the results is illustrated both theoretically and numerically. [ABSTRACT FROM AUTHOR]

A fast retransmit, which reduces the sender’s waiting time before retransmitting a lost segment, is applied to guarantee data integrity with no data loss in transmission. Based on fast retransmit, many application protocols have been enhanced and evolved to ensure quality of service and reduce data transmission time. One of application protocols is the multipath transmission control protocol which is catholically applied in modern computer networks. Communication lines used in this kind of network have different states, namely, failure, partial failure, and maintenance. Therefore, a computer network with a fast retransmit can be classified as stochastic and is called a stochastic-flow computer network with a fast retransmit (SCNFR). This paper assesses the system reliability of SCNFR for the successful transmission of demand d through ${k}$ (${k} \,\, >1$) separate minimal paths (${k}$ SMiP) under the latency. An algorithm is proposed to find all minimal capacity vectors (MCVs) that satisfy the demand and latency. Then, the system reliability is computed based on all MCVs. We adopt two practical cases of the pan-European research and education network and the Taiwan academic network to explore the effectiveness of the algorithm. The results show that the system reliability can be classified as decision reference while the manager decides the better ${k}$ SMiP with higher system reliability. [ABSTRACT FROM AUTHOR]

Since nondeterministic behavior is key to exposing shared-memory errors, nonsynchronized parallel programs are often used for verification and test of multicore chips. In the verification phase, however, the slow execution in a simulator requires nonconventional constraints for enabling error exposure with shorter programs. This paper proposes two novel techniques that build upon conventional random test generation for efficient shared-memory verification. The first technique exploits canonical dependence chains for constraining the random generation of instruction sequences so that the races induced at runtime are likely to raise the coverage of state transitions due to memory events conflicting at a same shared location. The second one exploits address space constraints for biasing random address assignment so that the competition of distinct shared locations for a same cache set can be controlled for raising the coverage of state transitions due to eviction events. We built generators relying on each of the proposed techniques, as well as on their combination, and we compared them to a conventional constrained random test generator for 8, 16, and 32-core architectures. Each of the four generators synthesized 1200 distinct test programs for verifying ten faulty designs derived from each of the three architectures (144 000 verification runs in total). For 32-core designs, the combination of the proposed techniques made at least 50% of the generation space capable of exposing errors, improved the median functional coverage by 44% and 83% at the two highest hierarchical levels, and reduced the average verification effort by one order of magnitude in many cases. [ABSTRACT FROM AUTHOR]

In this paper, the noncooperative optimal control problem is investigated for a class of discrete time-varying networked control systems subject to exogenous nonlinear disturbances. To relive the transmission burden in the sensor-to-controller channel, the Round-Robin protocol is adopted to schedule the sensor transmissions. On the other hand, the controller operates in an event-triggered manner so as to reduce the transmission frequency and thereby preserving the energy in the controller-to-actuator channel. In the presence of the underlying scheduling and triggering mechanism, it is literally impossible to acquire the accurate value of the individual cost function for each controller and, as an effective alternative, a certain upper bound is derived on the individual cost function. Then, in virtue of the completing-the-square technique and the Moore–Penrose pseudo inverse, such an upper bound is minimized at each time instant. Furthermore, a sufficient condition is established to guarantee the boundedness of the derived upper bound over the infinite horizon. Finally, a numerical example on the power grid is provided to verify the validity of the proposed methodology. [ABSTRACT FROM AUTHOR]

The increasing complexity of distributed real-time control systems in the vehicular area has led to the development of new protocols, such as controller area network with a flexible data rate (CAN-FD), that provides high-bandwidth communication with FD rate. Different topologies are used to interconnect electronic control units in safety-critical applications in the automotive area and the applied communication protocols, such as CAN-FD, must comply with reliability requirements. Moreover, the functional operations must be tested to their limits, since they require appropriate assessment techniques for different application scenarios. Recent research has highlighted that power switching systems cause transient faults that affect the communication network. In light of this concern, this paper explores the IEC/TS 62228:2007 and ISO 26262-3/4/9:2018 standards that can act as guidelines for the development of a test method and testing board for evaluating the impact of electrical fast transients on the performance of a distributed automotive control system. Metrics such as difference jitter, average jitter, and packet loss, are used to determine the fault impact on the control law of a critical vehicular control system. The experiments that were conducted show that during the four test scenarios in which the testing board was used, the average jitter increased from 10.41 to 29.05% in the worst case scenario. These results highlight the importance of carrying out consistent tests to prevent critical situations and that these data can be used in software requirements specification phases to improve reliability in vehicular control systems. [ABSTRACT FROM AUTHOR]

Hybrid ac/dc power systems will rely on power electronics to enable controlled energy exchange between different dc and ac systems. Multiport dc–dc–ac (MP-DC2AC) converters offer the ability to exchange power between two dc systems and an ac system using a single converter structure. Potential benefits include reduced energy conversion stages and a more compact station footprint. To date, limited information is available on modeling, operation, and control of MP-DC2AC converters suitable for HVDC and MVDC applications. This paper helps to fill this gap by presenting a generalized modeling and control framework for two yet unexplored MP-DC2AC modular multilevel converters. Based on derived analytical models of internal power transfer mechanisms, a dynamic controller is proposed that allows independent control of port power flows while keeping capacitor voltages regulated. Results are validated by extensive time-domain simulations. A comprehensive comparative analysis between four different MP-DC2AC topologies is carried out. [ABSTRACT FROM AUTHOR]

This paper studies the achievable throughput performance of the cognitive uplink under a limited primary cooperation scenario wherein the primary base station cannot feed back all interference channel gains to the secondary base station. To cope with the limited primary cooperation, we propose a feedback protocol called K -out-of- N feedback protocol, in which the primary base station feeds back only the KN smallest interference channel gains, out of N of them, to the secondary base station. We characterize the throughput performance under the K -out-of- N feedback protocol by analyzing the achievable multiuser diversity gains (MDGs) in cognitive uplinks for three different network types. Our results show that the proposed feedback mechanism is asymptotically optimum for interference-limited (IL) and individual-power-and-interference-limited (IPIL) networks for a fixed positive KN . It is further shown that the secondary network throughput in the IL and IPIL networks (under both the full and limited cooperation scenarios) logarithmically scales with the number of users in the network. In total-power-and-interference-limited (TPIL) networks, on the other hand, the K -out-of- N feedback protocol is asymptotically optimum for {K_{N}}= N^\delta , where \delta \in \left ({0,1}\right )$ . We also show that, in TPIL networks, the secondary network throughput under both the limited and full cooperation scales logarithmically double with the number of users in the network. These results indicate that the cognitive uplink can achieve the optimum MDG even with limited cooperation from the primary network. They also establish the dependence of pre-log throughput scaling factors on the distribution of fading channel gains for different network types. [ABSTRACT FROM AUTHOR]

Proliferation of virtualized systems opens a new opportunity to improve the scalability of multi-core architectures. Among the scalability bottlenecks in multi-cores, cache coherence has been one of the most critical problems. Although snoop-based protocols have been dominating commercial multi-core designs, it has been difficult to scale them for more cores, as snooping protocols require high network bandwidth and power consumption for snooping all the caches.In this paper, we propose a novel snoop-based cache coherence protocol, called virtual snooping, for virtualized multi-core architectures. Virtual snooping exploits memory isolation across virtual machines and prevents unnecessary snoop requests from crossing the virtual machine boundaries. Each virtual machine becomes a virtual snoop domain, consisting of a subset of the cores in a system. Although the majority of virtual machine memory is isolated, sharing of cachelines across VMs still occur. To address such data sharing, this paper investigates three factors, data sharing through the hypervisor, virtual machine relocation, and content-based sharing. In this paper, we explore the design space of virtual snooping with experiments on emulated and real virtualized systems including the mechanisms and overheads of the hypervisor. In addition, the paper discusses the scheduling impact on the effectiveness of virtual snooping. [ABSTRACT FROM AUTHOR]

The time synchronization in vehicular ad hoc networks (VANETs) has gained significant attention in recent times. In this paper, we focus on the time synchronization in large-scale VANETs and propose an adaptive beacon time synchronization (ABTS) algorithm to enhance timing message synchronization. ABTS algorithm selects the best time synchronization pairs to decrease the number of timing messages transmitted. To guarantee the reliability of synchronization, the clock offset of the connected vehicles periodically readjust to provide a better degree of synchronization accuracy with minimum energy consumption. Based on two-way timing message synchronization, we derive maximum likelihood (ML) estimation and its equivalent Cramer-Rao lower bound (CRLB) for clock offset design in the generalized sender-to-receiver system by assuming a Gaussian noise model. We propose node pair selection algorithms to improve pairwise beacon message timing synchronization. The simulation results validate that our proposed ABTS algorithm performs better than other protocols in terms of synchronization accuracy, the rate of convergence and energy efficiency. [ABSTRACT FROM AUTHOR]

This paper focuses on the mean square practical leader–following consensus of second-order nonlinear multiagent systems with noises and unmodeled dynamics, where all agents are influenced by noises emerging from the input channels. We present a new distributed protocol, which contains a designed signal to dominate the effects of unmodeled dynamics, to solve the mean square leader–following consensus problem for the nonlinear multiagent systems. The protocol is designed without using any global information, even the eigenvalues of the Laplacian matrix. The Lipschitz constant of the nonlinear function is also unknown to all followers. Using the Lyapunov functional approach and the stochastic theory, it is proven that the mean square practical leader–following consensus is achieved by the designed protocol. Finally, two examples are provided to illustrate the effectiveness of the designed algorithm. [ABSTRACT FROM AUTHOR]

This paper is concerned with the fault-tolerant consensus control for a class of uncertain multiagent systems (MASs) via weighted edge dynamics. Different from the existing consensus results, the considered communication graph is weighted and the system model is assumed to be completely unknown. First, based on an important factorization of Laplacian matrix, a novel system named as weighted edge dynamics is introduced, and it is then proved that the stabilizing controller design for the transformed weighted edge dynamics is equivalent to the consensus controller design for the initial MAS. Within this framework, an efficient data-based algorithm is given to derive the fault-tolerant stabilizing controller, and the consensus of the initial MAS can be further ensured under the designed control protocol. Finally, some simulation examples on the LC oscillator networks are given to demonstrate the validity of theoretical results. [ABSTRACT FROM AUTHOR]

The compute-and-forward (C&F) protocol in quasi-static channels normally employs lattice codes based on the rational integers $\mathbb {Z}$ , the Gaussian integers $\mathbb {Z} [i]$ , or the Eisenstein integers $\mathbb {Z} [\omega ]$ , while its extension to more general channels often assumes channel state information at transmitters (CSIT). In this paper, we propose a novel scheme for C&F in block-fading channels without CSIT, which is referred to as ring C&F because the fading coefficients are quantized to the canonical embedding of a ring of algebraic integers. Owing to the multiplicative closure of the algebraic lattices employed, a relay is able to decode an algebraic–integer linear combination of lattice codewords. We analyze its achievable computation rates and show it outperforms conventional C&F based on the $\mathbb {Z}$ -lattices. By investigating the effect of the Diophantine approximation by algebraic conjugates, we prove that the degrees of freedom (DoFs) of the optimized computation rate are ${n}/{L}$ , where $n$ is the number of blocks and $L$ is the number of users. [ABSTRACT FROM AUTHOR]

Recently, the demagnetization has been actively researched to reduce the magnetic field of a warship according to the development of the magnetic detection technology of the magnetic mines. In these studies, it was assumed that the warship was composed of one magnetic material in order to establish an effective deperming protocol. However, since the actual warship was composed of various materials, the magnetic interaction between the materials inevitably occurs during the demagnetization process. Due to the interaction, demagnetization may not be performed well. Therefore, in this paper, the effects of interactions in demagnetization of multiple materials were studied by using the Preisach model, and the optimal protocol was proposed. [ABSTRACT FROM AUTHOR]

In a cognitive radio network (CRN), two nodes have a rendezvous when they tune to the same channel simultaneously. Providing rendezvous guarantee between any pair of nodes is essential because a rendezvous is necessary for communication. Some existing works claim that rendezvous guarantee can be provided by using a dedicated common control channel to negotiate the channel being used. A serious problem of these mechanisms is that a globally available channel may not exist. Some channel hopping protocols try to provide a rendezvous guarantee without using a common control channel. However, these solutions may suffer from a poor number of rendezvous or uneven channel utilization. In this paper, we propose a novel distributed channel hopping protocol: Quorum and Latin square channel hopping (QLCH). The QLCH scheme efficiently provides rendezvous guarantee by utilizing the concept of quorum systems and Latin squares. The former is utilized to guarantee balanced rendezvous among nodes, whereas the latter is adopted to share the rendezvous among channels. QLCH efficiently provides fast rendezvous guarantee and can cooperate with other channel hopping protocols to enhance network throughput. Analytical and simulation results verify the improvement of QLCH. For example, when there are 30 flows using 11 channels in a CRN, the achieved time to rendezvous of QLCH is 9.84 times lower than that of the existing protocol SYNC-ETCH, whereas the achieved network throughput of QLCH is 362% higher than that of the existing protocol, i.e., Quorum-based channel hopping (L-QCH). [ABSTRACT FROM PUBLISHER]

We show an explicit (that is, efficient and deterministic) capacity approaching interactive coding scheme that simulates any interactive protocol under random errors with nearly optimal communication rate. Specifically, over the binary symmetric channel with crossover probability $\epsilon $ , our coding scheme achieves a communication rate of $1 - O(\sqrt {H({\epsilon })})$ , together with negligible $\exp (-\Omega (\epsilon ^{4}\,\,n/\log n))$ failure probability (over the randomness of the channel). A rate of $1 - \tilde \Theta (\sqrt {H({\epsilon })})$ is likely asymptotically optimal as a result of Kol and Raz (2013) suggests. Prior to this paper, such a communication rate was achievable only using randomized coding schemes [Kol and Raz (2013); Hauepler (2014)]. [ABSTRACT FROM AUTHOR]

This paper proposes a novel decentralized on-line fault diagnosis approach based on the solution of some integer linear programming problems for discrete event systems in a Petri net framework. The decentralized architecture consists of a set of local sites communicating with a coordinator that decides whether the system behavior is normal or subject to some possible faults. To this aim, some results allow defining the rules applied by the coordinator and the local sites to provide the global diagnosis results. Moreover, two protocols for the detection and diagnosis of faults are proposed: they differ for the information exchanged between local sites and coordinator and the diagnostic capability. In addition, a sufficient and necessary condition under which the second presented protocol can successfully diagnose a fault in the decentralized architecture is proved. Finally, some examples are presented to show the efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

We recently proposed a convolutional neural network (CNN) for remote sensing image pansharpening obtaining a significant performance gain over the state of the art. In this paper, we explore a number of architectural and training variations to this baseline, achieving further performance gains with a lightweight network that trains very fast. Leveraging on this latter property, we propose a target-adaptive usage modality that ensures a very good performance also in the presence of a mismatch with respect to the training set and even across different sensors. The proposed method, published online as an off-the-shelf software tool, allows users to perform fast and high-quality CNN-based pansharpening of their own target images on general-purpose hardware. [ABSTRACT FROM AUTHOR]

This paper clearly demonstrates the architecture of time synchronization network of experimental advanced superconducting tokamak (EAST) poloidal field (PF) power supply control system and analyzes characteristics of the IEEE 1588 in detail at the same time. IEEE 1588 has unique advantages for this paper to utilize as protocol in order to improve the accuracy of the time synchronization network (TSN). Consequently, we design a time synchronization system based on PCI eXtensions for Instrumentation-6683H. This paper utilizes one master node to synchronize all slave nodes on the time network in each second. The result shows that the synchronization accuracy can be achieved within 50 ns. According to results of experiments, this system can perfectly meet the requirements of EAST PF power supply control system. [ABSTRACT FROM AUTHOR]

An important ingredient of the future 5G systems will be ultra-reliable low-latency communication (URLLC). A way to offer URLLC without intervention in the baseband/PHY layer design is to use interface diversity and integrate multiple communication interfaces, each interface based on a different technology. In this paper, we propose to use coding to seamlessly distribute coded payload and redundancy data across multiple available communication interfaces. We formulate an optimization problem to find the payload allocation weights that maximize the reliability at specific target latency values. In order to estimate the performance in terms of latency and reliability of such an integrated communication system, we propose an analysis framework that combines traditional reliability models with technology-specific latency probability distributions. Our model is capable to account for failure correlation among interfaces/technologies. By considering different scenarios, we find that the optimized strategies can in some cases significantly outperform strategies based on $k$ -out-of- $n$ erasure codes, where the latter do not account for the characteristics of the different interfaces. The model has been validated through simulation and is supported by experimental results. [ABSTRACT FROM PUBLISHER]

Real-time media flow protocol (RTMFP) is a protocol developed by Adobe for multimedia delivery under both client–server and peer-to-peer (P2P) paradigms. Currently, major Internet video service providers, such as PPTV and iQIYI, have already built their Web-based video streaming systems with RTMFP. In such a system, a user only needs to install a Flash Player plug-in on his Web browser, and can stream videos in a peer-assisted way. Despite its wide usage, RTMFP has received little attention from the measurement community. In this paper, we select PPTV as an example and study the RTMFP video streaming technology with a measurement approach. We reveal the architecture of PPTV’s RTMFP streaming system and show that, compared with proprietary P2P networks, the RTMFP network has a different content distribution policy, and exhibits different features on peers’ streaming behaviors, potential system bottleneck, and network dynamics. We also study RTMFP’s video transmission and find that the protocol’s selective retransmission scheme can effectively overcome packet losses and improve the video playback quality; however, the TCP-like congestion control mechanism of RTMFP does not lead to fairness between RTMFP and Transmission Control Protocol (TCP) traffics, due to the mismatch between the inherited pull-based video segment distribution model of the P2P streaming application and the protocol’s built-in congestion control mechanism. This paper provides insights into the RTMFP-based video streaming technology and is helpful for people to construct better peer-assisted video systems with RTMFP. [ABSTRACT FROM PUBLISHER]

Consider a group of stations connected through a multiple-access channel, with the constraint that if at a time instant exactly one station transmits a message, then the message is successfully received by any other station, whereas if two or more stations simultaneously transmit their messages then a conflict occurs and all messages are lost. Let us assume that $n$ is the number of stations and that an (arbitrary) subset $A$ of them, $|A|\leq k\leq n$ , is active, that is, there are at most $k$ stations that have a message to send over the channel. In the classical conflict resolution problem, the issue is to schedule the transmissions of each station to let every active station use the channel alone (i.e., without conflict) at least once, and this requirement must be satisfied whatever might be the set of active stations $A$ . The parameter to optimize is, usually, the worst case number of transmissions that any station has to attempt before all message transmissions are successful. In this paper, we study the following question: is it possible to obtain a significant improvement on the protocols that solve the classical conflict resolution problem if we allow the protocols to fail over a “small” fraction of all possible subsets of active stations? In other words, is it possible to significantly reduce the number of transmissions that must be attempted if the set of active stations is chosen uniformly at random and the conflict resolution algorithm is only required to work correctly with “high” probability? In this paper, we will show that this is indeed the case. Our main technical tool is a generalization of selectors, a recently introduced combinatorial structure that has found applications in several areas. As it turned out for selectors, we believe that our new combinatorial structures are likely to be useful also outside the present context. [ABSTRACT FROM PUBLISHER]