Gaussian thermal loss channels are of particular importance to quantum communication theory since they model realistic optical communication channels. Except for special cases, the quantum capacity ...of Gaussian thermal loss channels is not yet quantified completely. In this paper, we provide improved upper bounds of the Gaussian thermal loss channel capacity, both in energy-constrained and unconstrained scenarios. We briefly review Gottesman-Kitaev-Preskill (GKP) codes and discuss their experimental implementation. We then prove, in the energy-unconstrained case, that a family of GKP codes achieves the quantum capacity of Gaussian thermal loss channels up to at most a constant gap from the improved upper bound. In the energy-constrained case, we formulate a biconvex encoding and decoding optimization problem to maximize entanglement fidelity. Then, we solve the biconvex optimization heuristically by an alternating semi-definite programming method and report that, starting from Haar random initial codes, our numerical optimization yields a hexagonal GKP code as an optimal encoding in a practically relevant regime.
Bilateral teleoperation technology has been widely concerned by its unique advantages in human-machine interaction-based cooperative operation systems. Communication delay, various nonlinearities, ...and uncertainties in teleoperation system are the main challenging issues to achieve system stability and good transparency performance. In this paper, a globally stable adaptive fuzzy backstepping control design is proposed for nonlinear bilateral teleoperation manipulators to handle the aforementioned issues. For the communication channel, instead of direct transmission of environmental torque signals, the fuzzy-based nonpower approximate environmental parameters are transmitted to the master side for environmental torque prediction, which effectively avoids the transmission of power signals in the delayed communication channel and solves the passivity problem in the traditional teleoperation system. A trajectory generator is implemented in the master side and a trajectory smoothing is applied in the slave side. Subsequently, nonlinear adaptive fuzzy backstepping controllers for master and slave are separately designed to handle the nonlinearities and uncertainties. Theoretically, the great transparency performance of both position tracking and force feedback can be achieved, and the global stability is still guaranteed under communication delay. Comparative experiments are conducted on the real platform, which verify the effectiveness and advantages of the proposed control design in some typical working scenarios.
By engaging in corporate social responsibility (CSR) activities, companies can not only generate favorable stakeholder attitudes and better support behaviors (e.g. purchase, seeking employment, ...investing in the company), but also, over the long run, build corporate image, strengthen stakeholder–company relationships, and enhance stakeholders' advocacy behaviors. However, stakeholders' low awareness of and unfavorable attributions towards companies' CSR activities remain critical impediments in companies' attempts to maximize business benefits from their CSR activities, highlighting a need for companies to communicate CSR more effectively to stakeholders. In light of these challenges, a conceptual framework of CSR communication is presented and its different aspects are analyzed, from message content and communication channels to company‐ and stakeholder‐specific factors that influence the effectiveness of CSR communication.
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Optical fibre underpins the global communications infrastructure and has experienced an astonishing evolution over the past four decades, with current commercial systems transmitting data rates in ...excess of 10 Tb/s over a single fibre core. The continuation of this dramatic growth in throughput has become constrained due to a power dependent nonlinear distortion arising from a phenomenon known as the Kerr effect. The mitigation of fibre nonlinearities is an area of intense research. However, even in the absence of nonlinear distortion, the practical limit on the transmission throughput of a single fibre core is dominated by the finite signal-to-noise ratio (SNR) afforded by current state-of-the-art coherent optical transceivers. Therefore, the key to maximising the number of information bits that can be reliably transmitted over a fibre channel hinges on the simultaneous optimisation of the modulation format and code rate, based on the SNR achieved at the receiver. In this work, we use an information theoretic approach based on the mutual information and the generalised mutual information to characterise a state-of-the-art dual polarisation m-ary quadrature amplitude modulation transceiver and subsequently apply this methodology to a 15-carrier super-channel to achieve the highest throughput (1.125 Tb/s) ever recorded using a single coherent receiver.
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The Internet of Things (IoT) revitalizes the world with tremendous capabilities and potential to be utilized in vehicular networks. The Smart Transport Infrastructure (STI) era depends mainly on the ...IoT. Advanced machine learning (ML) techniques are being used to strengthen the STI smartness further. However, some decisions are very challenging due to the vast number of STI components and big data generated from STIs. Computation cost, communication overheads, and privacy issues are significant concerns for wide-scale ML adoption within STI. These issues can be addressed using Federated Learning (FL) and blockchain. FL can be used to address the issues of privacy preservation and handling big data generated in STI management and control. Blockchain is a distributed ledger that can store data while providing trust and integrity assurance. Blockchain can be a solution to data integrity and can add more security to the STI. This survey initially explores the vehicular network and STI in detail and sheds light on the blockchain and FL with real-world implementations. Then, FL and blockchain applications in the Vehicular Ad Hoc Network (VANET) environment from security and privacy perspectives are discussed in detail. In the end, the paper focuses on the current research challenges and future research directions related to integrating FL and blockchain for vehicular networks.
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36.
A Survey of Man In The Middle Attacks Conti, Mauro; Dragoni, Nicola; Lesyk, Viktor
IEEE Communications surveys and tutorials,
01/2016, Volume:
18, Issue:
3
Journal Article
Peer reviewed
The Man-In-The-Middle (MITM) attack is one of the most well known attacks in computer security, representing one of the biggest concerns for security professionals. MITM targets the actual data that ...flows between endpoints, and the confidentiality and integrity of the data itself. In this paper, we extensively review the literature on MITM to analyse and categorize the scope of MITM attacks, considering both a reference model, such as the open systems interconnection (OSI) model, as well as two specific widely used network technologies, i.e., GSM and UMTS. In particular, we classify MITM attacks based on several parameters, like location of an attacker in the network, nature of a communication channel, and impersonation techniques. Based on an impersonation techniques classification, we then provide execution steps for each MITM class. We survey existing countermeasures and discuss the comparison among them. Finally, based on our analysis, we propose a categorisation of MITM prevention mechanisms, and we identify some possible directions for future research.
The digitization of the banking sector is not a novelty. It has been occurring much faster compared to many other business sectors. Consequently, banks have also accepted digital advertising channels ...for their services offered to users. Their goal was undoubtedly to keep pace with the times, enhance user experience, and increase their revenue. Loans, as the most significant banking service, have not remained immune to the process of digitization. Nowadays, banks offer loans through their mobile applications, electronic banking, websites, social networks, as well as through paid advertising and marketing collaborations. The aim of this study is to analyze the efficiency of digital communication channels in offering banking loans through the application of empirical analysis. To achieve this, a survey was conducted in the Nišava District, followed by data processing using the SPSS software package. The obtained results indicate that loan advertising through digital platforms has a greater impact on women in the Nišava District. Additionally, factors such as education level, monthly income, and security significantly influence the visibility of ads, opening rates, and communication with banks via digital channels, as perceived by users.
During the communication process of malware, a large amount of malicious traffic will be generated, malicious traffic usually uses various methods to avoid traditional security protection and ...detection. With the development of the Internet, public blockchains (such as Bitcoin, Ethereum, etc.) are frequently exploited by attackers to build malicious traffic communication channels. Because the blockchain has the characteristics of anonymity, decentralization, immutability, and difficulty in closure, and the blockchain provides a distributed P2P networking at the bottom. This paper investigates three botnet models which employ blockchain technology to build malicious traffic communication channels. By analyzing the security threats of malicious traffic communication technology based on blockchain, this paper examines its issues and challenges, along with possible future research directions including possible countermeasures.
As Cooperative Extension Services (CES) grow, agriculture evolves, and urbanization increases, Extension professionals are challenged to continue meeting the needs of their constituents by providing ...reliable, research-backed information to their communities. This includes utilizing appropriate communication means to reach their constituents. Therefore, the purpose of this study was to examine the communication preferences of University of Idaho CES professionals and their constituents and the communication types and channels most used. We used a cross-sectional descriptive census survey design and administered the survey to all University of Idaho CES faculty and educators. We analyzed the data via descriptive statistics, Wilcoxon signed rank tests, and paired sample t-tests. University of Idaho CES professionals ranked mainly individual communication channels as their preferred method of communication. However, they felt their constituents may prefer mass or group communication channels more than they do. CES professionals should utilize audience segmentation to serve their constituents better. COVID-19 also significantly increased the time spent preparing communications and utilizing mass communications. While technological-based communication increased during COVID-19, it is important to consider access and availability to constituents. Understanding what resources constituents have available and how they prefer to receive their information, can help CES professionals maintain relationships with their audiences.
This paper considers the design of structured Luenberger observers to generate sparse sensor-estimator communication networks. We first illustrate the relationship between the topology of ...communication channels and the structure of the observer gain matrix. To balance the estimation error and the communication cost, we formulate the design of the sparsity-promoting observer as a regularized <inline-formula><tex-math notation="LaTeX">\ell _{1}</tex-math></inline-formula>-optimization problem. Then we characterize its first-order optimality condition using gradient information and propose a linear programming method to verify stationary solutions. We further develop a multi-block alternating direction method of multipliers (ADMM) algorithm with linear matrix inequality-based warm start for computation. We prove that the solution returned by our algorithm is at least a stationary solution. Numerical simulations are provided to verify the proposed theoretical results and show that the communication burden of networked control systems can be greatly relieved by using the designed observers.
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