Sensing and networking have been regarded as key enabling technologies of future smart vehicles. Sensing allows vehicles to be context awareness, while networking empowers context sharing among ...ambients. Existing vehicular communication solutions mainly rely on homogeneous network, or heterogeneous network via data offloading. However, today's vehicular network implementations are highly heterogeneous. Therefore, conventional homogeneous communication and data offloading may not be able to satisfy the requirement of the emerging vehicular networking applications. In this paper, we apply the software-defined network (SDN) to the heterogeneous vehicular networks to bridge the gaps. With SDN, heterogeneous network resources can be managed with a unified abstraction. Moreover, we propose an SDN-based wireless communication solution, which can schedule different network resources to minimize communication cost. We investigate the problems in both single and multiple hop cases. We also evaluate the proposed approaches using traffic traces. The effectiveness and the efficiency are validated by the results.
Trust-based service management in IoT systems, a promising research direction provides an intelligent solution for the identification of appropriate and trustworthy service providers from a huge of ...number smart nodes providing similar services. An efficient trust-based service ranking scheme (TBSRS) is proposed. The novelty of our design lies in providing accurate trust evaluation and service ranking in the absence of assessment data or presence of untrustworthiness recommendations. TBSRS also addresses the issue about the trustworthiness evaluation of a new service. Service providers are ranking based on the binary fruit fly optimization algorithm in TBSRS. The experimental results demonstrate desirable convergence, accuracy, and resiliency properties of TBSRS, and also demonstrate that TBSRS outperforms Adaptive IoT Trust and IoT-HiTrust in terms of the precision of service selection and other a few performance metrics.
Trust systems have been widely studied in Internet of Things (IoT). However, there is a little work done on trust management in cross-domain Industrial Internet of Things (IIoT). Many of these models ...focus mainly or only on trust management in a single administrative domain where trust is evaluated based on the same criteria. In general, different administrative domains adopt different trust models and trust evaluation standards. Due to different trust evaluation standards, trust values from different administrative domain cannot be compared, directly. Therefore, there is a need for a well-defined trust computing scheme for such multi-domain IIoT environment. This paper focuses on the research of cross-domain trust and proposes a cross-domain trust computing scheme “CDTCS”, where trust recommendation value for an IIoT device in a domain can be transferred to a corresponding value in another domain. We analyze CDTCS performance in terms of trust accuracy and resiliency against attacks.
Abstract
Overlapping radio signals recognition is attracting more attention as the development and ubiquitous application of radio technologies. The traditional blind signal separation (BSS) method ...is mostly not effective when both radio propagation effects and low signal‐to‐noise ratio (SNR) scenarios are taken into consideration. In this letter, joint conformer and CNN model (JCCM) is proposed to separate and recognize the overlapping radio signals which are also unknown by the monitor node. JCCM utilizes the attention mechanism of conformer to encode signal spectrum into feature maps and decodes the feature maps into signal component proportions by perceiving the global and local features through convolutional neural networks (CNN). In addition, a signal preprocessing module is designed including MinPool and AvgPool layers for signal denoising. JCCM is evaluated in terms of signal separation, scaling preservation and principal signal classification experiments. The results show that JCCM has better performance especially in low SNR conditions.
In this paper, we study the three-dimensional (3D) trajectory optimization problems of unmanned aerial vehicles (UAV) with a solar energy supply, aiming to provide communication coverage for mobile ...users on the ground. In general, the higher UAVs fly, the more solar energy they collect, but the smaller the range of coverage they could achieve, and vice versa. How to plan optimal trajectories for UAVs so that more users can be encompassed, while allowing UAVs to collect enough solar energy, is a challenging issue. Moreover, we also consider how geographically fair coverage for each ground user can be achieved. To solve these problems, we designed a multiple solar-powered UAV (SP-UAV) energy consumption model and a fairness model, while designed an observation space, state space, action space, and reward function. Then, we proposed a multiple SP-UAV 3D trajectory optimization algorithm based on deep reinforcement learning (DRL). Our algorithm is able to balance the energy consumption of UAVs to extend the system’s lifetime, while avoiding both collisions and flying out of communication range. Finally, we trained our model through simulation experiments and conducted comparative experiments and analysis based on real network topology data. The results show that our algorithm is superior to the existing typical algorithms in coverage, fairness, and lifetime.
Fog-based Vehicular ad-hoc networks (VANETs) are new kinds of network that combine fog computing and mobile ad-hoc networks appeared in recent years, which can be used in monitoring traffic, smart ...driving, safe driving, and so on. Fog-based VANET is composed of a large number of dynamic nodes and static nodes, which is a heterogeneous network. Due to the heterogeneity of fog-based VANET, there is a large difference in clock rate between different nodes. It makes clock of nodes soon become inconsistent. The inaccurate clocks would lead to problems such as imprecise duty-cycle scheduling and wrong events sequence, etc. Synchronizing the clocks needs multiple message exchanges among the nodes. However, due to the mobility of the fog-based VANET, the network topology changes dynamically, which may cause synchronization packets to fail to be transmitted to a node that needs to be synchronized. In this paper, a precise time synchronization mechanism for fog-based VANET is proposed. The mechanism uses two-way message exchange method to estimate clock offset through analyzing the mobility of dynamic nodes. Clock skew is corrected using a carrier frequency offset (CFO) based hardware clock frequency estimation and considering the Doppler effect. Theoretical analyses and simulation results show that our time synchronization mechanism achieves highly accurate time synchronization.
In wireless sensor networks, rotating dominating set is an efficient method for balancing the energy consumption of nodes, and thereby extending the network operational time. This method can be ...abstracted as <inline-formula> <tex-math notation="LaTeX">k </tex-math></inline-formula>-Lifetime Dominating Set in bipartite graph, that partitions the set of graph vertices representing sensors into <inline-formula> <tex-math notation="LaTeX">k </tex-math></inline-formula> disjoint dominating sets. However, the considered problem has been proven to be NP-hard, and there is no hope of solving it in polynomial time unless P = NP. Existing studies mainly focus on developing approximation or heuristic algorithms, which usually cannot guarantee a solution for a given problem yes instance. In this study, we first propose a randomized algorithm that can generate a solution with guaranteed probability 1-<inline-formula> <tex-math notation="LaTeX">\varepsilon </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">0 < \varepsilon < 1 </tex-math></inline-formula>). Using the color coding method, we show that the randomized algorithm can be improved to guarantee the generation of a solution for a given problem yes instance in exponential time. Based on the idea of randomized partition, we further present a more practical centralized greedy algorithm, and then a distributed implementation. Simulation results indicate that the centralized algorithm can efficiently generate optimal solutions for almost all the given problem instances if the partition redundancy is above a certain limit. Compared with existing algorithm, the centralized algorithm increases the number of dominating sets by factors between 0% and 21%.
Noninvasive prenatal testing (NIPT), which involves analysis of circulating cell-free fetal DNA (cffDNA) from maternal plasma, is highly effective for detecting feto-placental chromosome aneuploidy. ...However, recent studies suggested that coverage-based shallow-depth NIPT cannot accurately detect smaller single or multi-loci genetic variants. To assess the fetal genotype of any locus using maternal plasma, we developed a novel genotyping algorithm named pseudo tetraploid genotyping (PTG). We performed paired-end captured sequencing of the plasma cell-free DNA (cfDNA), in which case a phenotypically healthy woman is suspected to be carrying a fetus with genetic defect. After a series of independent filtering of 111,407 SNPs, we found one variant in COL1A1 graded with high pathogenic potential which might cause osteogenesis imperfecta (OI). Then, we verified this mutation by Sanger sequencing of fetal and parental blood cells. In addition, we evaluated the accuracy and detection rate of the PTG algorithm through direct sequencing of the genomic DNA from maternal and fetal blood cells. Collectively, our study developed an intuitive and cost-effective method for the noninvasive detection of pathogenic mutations, and successfully identified a de novo variant in COL1A1 (c.2596 G > A, p.Gly866Ser) in the fetus implicated in OI.
A novel network paradigm of mobile edge computing, namely TMWSNs (two-tiered mobile wireless sensor networks), has just been proposed by researchers in recent years for its high scalability and ...robustness. However, only a few works have considered the security of TMWSNs. In fact, the storage nodes, which are located at the upper layer of TMWSNs, are prone to being attacked by the adversaries because they play a key role in bridging both the sensor nodes and the sink, which may lead to the disclosure of all data stored on them as well as some other potentially devastating results. In this paper, we make a comparative study on two typical schemes, EVTopk and VTMSN, which have been proposed recently for securing Top-
queries in TMWSNs, through both theoretical analysis and extensive simulations, aiming at finding out their disadvantages and advancements. We find that both schemes unsatisfactorily raise communication costs. Specifically, the extra communication cost brought about by transmitting the proof information uses up more than 40% of the total communication cost between the sensor nodes and the storage nodes, and 80% of that between the storage nodes and the sink. We discuss the corresponding reasons and present our suggestions, hoping that it will inspire the researchers researching this subject.
In the post-Cloud era, the proliferation of Internet of Things (IoT) has pushed the horizon of Edge computing, which is a new computing paradigm with data are processed at the edge of the network. As ...the important systems of Edge computing, wireless sensor and actuator networks (WSANs) play an important role in collecting and processing the sensing data from the surrounding environment as well as taking actions on the events happening in the environment. In WSANs, in-network data storage and information discovery schemes with high energy efficiency, high load balance and low latency are needed because of the limited resources of the sensor nodes and the real-time requirement of some specific applications, such as putting out a big fire in a forest. In this article, the existing schemes of WSANs on data storage and information discovery are surveyed with detailed analysis on their advancements and shortcomings, and possible solutions are proposed on how to achieve high efficiency, good load balance, and perfect real-time performances at the same time, hoping that it can provide a good reference for the future research of the WSANs-based Edge computing systems.
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