Realization of state equations by RC network and one controlled source†

The realization of a class of state equations by RC network and one voltage-controlled voltage source is described. The linear graph of the network has at least one complete tree such that the tree branches correspond to all capacitances, to all voltage sources and to the controlled source only.     

Why run 16 research and development centers in 3 continents? Wouldn’t one do?

We keep about 16,000 engineers on the ground across three continents to hear and understand your customers’ demands.     

Privacy preservation in secure group communications for?vehicular ad hoc networks

Secure communications for vehicular ad hoc networks (VANETs) have become an important research issue these years. Many protocols for secure vehicle-to-vehicle communications and vehicle-to-infrastructure communications have been proposed, yet fewer protocols are concerned with secure group communications for VANETs. Of those existing protocols for group communications, some of them form a group of vehicles based on geographical regions and provide broadcasting to the group members with or without message confidentiality. The others allow secure vehicle-to-vehicle communications within a group with session keys, but they do not preserve user privacy for communicating parties within the group. In this paper, we propose a novel group communication scheme for vehicular networks, in which a group is formed by a set of related vehicles of the same purpose, such as a platoon of recreational vehicles targeted for the same tourist spot. The scheme not only offers efficient and secure group communications but also provides privacy preservation for vehicle-to-vehicle communications within a group. Security analysis is given to demonstrate the robustness of the proposed scheme.     

Can energy optimization lead to economic and environmental waste in LPWAN architectures?

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.     

Consumers’ acceptance of information and communications technology in tourism: A review

The impact of information and communications technology (ICT) in tourism (e-tourism) has altered the ways tourism services are accessed and consumed. Ubiquitous and highly innovative ICTs provide different channels for consumers to use tourism services; thus, studies on e-tourism are numerous and fragmented. Different factors account for how consumers embrace these channels. The purpose of this study is to review studies on consumers’ acceptance or adoption of e-tourism in order to group the studies, synthesize the theories, models and frameworks used and identify the antecedents influencing consumers’ e-tourism acceptance and usage. A total of 71 studies from 2005 to 2016 (inclusive) from both tourism-based and non-tourism-based journals were selected, synthesized, and included. Based on their contexts, similarity and relevance, the 71 studies were segregated into three distinct groups. This study found that research among the groups is uneven. Implications and research directions are suggested.     

Zhao JiBin emphasizes China Tietong should enlarge private network coverage and make great progress in network regionalization

President Zhao Jibin of China Titong goes to Jiangsu to do some surveys and after listening to the working report of Jiangsu Tietong, he inspects the network development in Nanjing, Suzhou, Changzhou and other cities. Zhao JiBin emphasizes China Tietong should be on the way of ＂enlarge private network coverage and make great progress in network regionalization＂, make every effort to lay a solid management foundation and improve management level so as to ensure the accurate orientation and implement of the whole development strategy. All members of China Tietong must hold a clear understanding about future development direction.     

Cooperation-based resource allocation and call admission for?wireless network operators

The increasing number of radio access technologies and the availability of multi-radio devices boost the need for novel resource allocation schemes in cellular networks. This paper uses a cooperative game theoretic approach for resource allocation at the network level, while utilizing simultaneous use of available radio interfaces at the device level. We model resource allocation management using the well known bankruptcy model and apply Kalai-Smorodinsky bargaining solution method to find a distribution rule, based on which we propose resource allocation and call admission control schemes. Performance analysis of our allocation and control schemes demonstrates significant improvements over previous approaches in terms of utilization of the available bandwidth and the number of call drops. We also study the performance of proposed approach for different operator policies.     

Large-scale IP network behavior anomaly detection and?identification using substructure-based approach and?multivariate time series mining

In this paper, a substructure-based network behavior anomaly detection approach, called WFS (Weighted Frequent Subgraphs), is proposed to detect the anomalies of a large-scale IP networks. With application of WFS, an entire graph is examined, unusual substructures of which are reported. Due to additional information given by the graph, the anomalies are able to be detected more accurately. With multivariate time series motif association rules mining (MTSMARM), the patterns of abnormal traffic behavior are able to be obtained. In order to verify the above proposals, experiments are conducted and, together with application of backbone networks (Internet2) Netflow data, show some positive results.     

Bracketing or reinforcing? Socio-economic status,network power,and online deliberation

The extent to which the deliberative scenario brackets socio-economic inequalities (i.e., functioning as an ideal public sphere) has been long-debating. This study empirically addresses this question in the online setting. We test whether offline advantages (i.e., economic and cultural capitals) can be translated into power in online deliberation and how their dynamic relations further influence interlocutors’ deliberation experience (i.e., perceived procedural fairness and validity claim). Power is conceptualized as network power, including prestige (indegree), leadership (outdegree), and brokering power (betweenness). A national sample of Singaporeans participated in a three-week online deliberation, and network power is measured based on the web log. The participants answered a two-wave (i.e., pre- and post-deliberation) survey to indicate individual attributes. Structural equation modeling finds that online deliberation brackets as well as reinforces offline status. Economic capital is suppressed while cultural capital translates into network power, which further influences interlocutors’ evaluation of the deliberation.     

Nonlinear network coding based on multiplication and exponentiation in GF（2^m）

This article proposes a novel nonlinear network code in the GF(2m) finite field. Different from previous linear network codes that linearly mix multiple input flows, the proposed nonlinear network code mixes input flows through both multiplication and exponentiation in the GF(2m). Three relevant rules for selecting proper parameters for the proposed nonlinear network code are discussed, and the relationship between the power parameter and the coding coefficient K is explored. Further analysis shows that the proposed nonlinear network code is equivalent to a linear network code with deterministic coefficients.     

Can COVID-19 pandemic influence experience response in mobile learning?

The mass spreading of COVID-19 has changed the paradigm of the education industry. In China and many other nations, universities have introduced compulsory remote education programs such as mobile learning (m-learning) to prevent public health hazards caused by the pandemic. However, so far, there is still a lack of understanding of student’s learning experience responses in compulsory m-learning programs. As such, there is a necessity to explore the factors and mechanisms which drives students’ experience. This paper evaluates the influence of both pedagogy and technology on learner’s compulsory m-learning experience response (ER) by extending the mobile technology acceptance model (MTAM) during the COVID-19 pandemic. An online self-administered questionnaire was used to collect the data, which was then analysed through SmartPLS 3.2.9. Importance-performance matrix analysis was applied as a post-hoc procedure to gauge the importance and performance of the exogenous constructs. The results revealed that perceptions of m-learning’s learning content quality, user interface, and system’s connectivity affect the perceived mobile usefulness and easiness which in turn affects ER. This paper validates MTAM in the field of education by integrating MTAM with pedagogy and technology attributes under a social emergency setting such as the COVID-19 pandemic. In addition, the current research explains users' ER rather than behaviour intention which is commonly adopted in past studies.     

Can smartphones be specialists? Effects of specialization in mobile advertising

Based on the Computers Are Social Actors (CASA) paradigm, this study extends the expectations regarding the superiority of specialists over generalists to mobile technology by examining whether the specialization of a hardware agent (i.e., a smartphone) and a software agent (i.e., an application) has psychological effects on smartphone users who are exposed to mobile advertisements. Results from a between-subjects experiment (N = 80) show that specialist smartphones and applications induce greater trust in advertisements and an increased purchase intention toward the advertised products than generalist smartphones and applications. In addition, the effects of specialization on purchase intention are mediated by trust in advertisements. Theoretical and practical implications of these findings are discussed.     

Does the IEEE 802.11 MAC protocol work well in multihop wireless adhoc networks?

The IEEE 802.11 MAC protocol is the standard for wireless LANs; it is widely used in testbeds and simulations for wireless multihop ad hoc networks. However, this protocol was not designed for multihop networks. Although it can support some ad hoc network architecture, it is not intended to support the wireless mobile ad hoc network, in which multihop connectivity is one of the most prominent features. In this article we focus on the following question: can the IEEE 802.11 MAC protocol function well in multihop networks? By presenting several serious problems encountered in an IEEE 802.11-based multihop network and revealing the in-depth cause of these problems, we conclude that the current version of this wireless LAN protocol does not function well in multihop ad hoc networks. We thus doubt whether the WaveLAN-based system is workable as a mobile ad hoc testbed     

Forward and Reverse Converters and Moduli Set Selection in Signed-Digit?Residue?Number?Systems

This paper presents an investigation into using a combination of two alternative digital number representations; the residue number system (RNS) and the signed-digit (SD) number representation in digital arithmetic circuits. The combined number system is called RNS/SD for short. Since the performance of RNS/SD arithmetic circuits depends on the choice of the moduli set (a set of pairwise prime numbers), the purpose of this work is to compare RNS/SD number systems based on different sets. Five specific moduli sets of different lengths are selected. Moduli-set-specific forward and reverse RNS/SD converters are introduced for each of these sets. A generic conversion technique for moduli sets consisting of any number of elements is also presented. Finite impulse response (FIR) filters are used as reference designs in order to evaluate the performance of RNS/SD processing. The designs are evaluated with respect to delay and circuit area in a commercial 0.13 μm CMOS process. For the case of FIR filters it is shown that generic moduli sets with five or six moduli results in designs with the best area × delay products.

Are there so many sons per node in a wireless sensor network data aggregation tree?

Some authors seem to believe that the average number of sons in a Wireless Sensor Network (WSN) data aggregation tree can be kept constant, even when the distances from the sink increase. But this assumption is impossible to stand in a dense and uniformly deployed network, as the number of nodes in a given level would grow exponentially, while the perimeter just grows linearly. In this letter, it is shown that the average number of sons of a given tree node is in average a quite low number, slightly higher than one, and that it tends to 1, as the distance to sink, or node depth, increases, both for 2-D, and for 3-D WSNs.