Data collection algorithm for wireless sensor networks using collaborative mobile elements

The simplest approach to reduce network latency for data gathering in wireless sensor networks (WSN) is to use multiple mobile elements rather than a single mobile sink. However, the most challneging issues faced this approach are firstly the high network cost as a result of using large number of mobile elements. Secondly, it suffers from the difficulty of network partitioning to achieve an efficient load balancing among these mobile elements. In this study, a collaborative data collection algorithm (CDCA) is developed. Simulation results presented in this paper demonstrated that with this algorithm the latency is significantly reduced at small number of mobile elements. Furthermore, the performance of CDCA algorithm is compared with the Area Splitting Algorithm (ASA). Consequently, the CDCA showed superior performance in terms of network latency, load balancing, and the required number of mobile elements

Data Gathering in Wireless Sensor Networks Using Intermediate Nodes

ABSTRACT Energy consumption is an essential concern to Wireless Sensor Networks (WSNs).The major cause of the energy consumption in WSNs is due to the data aggregation. A data aggregation is a process of collecting data from sensor nodes and transmitting these data to the sink node or base station. An effective way to perform such a task is accomplished by using clustering. In clustering, nodes are grouped into clusters where a number of nodes, called cluster heads, are responsible for gathering data from other nodes, aggregate them and transmit them to the Base Station (BS). In this paper we produce a new algorithm which focused on reducing the transmission bath between sensor nodes and cluster heads. A proper utilization and reserving of the available power resources is achieved with this technique compared to the well-known LEACH_C algorithm

Physical layer security for authentication, confidentiality, and malicious node detection: a paradigm shift in securing IoT networks

The pervasiveness of commercial Internet of Things (IoT) around the globe is expected to reach significant levels with the upcoming sixth generation of mobile networks (6G). Throughout the past years, wireless standardization units worldwide have been prominently active in the deployment and performance optimization of such IoT networks and fusing them with current and futuristic cellular networks. Nonetheless, the openness of wireless transmissions and the forecasted overwhelm in connected devices will provoke unprecedented security leakages and vulnerabilities. In addition to the key targets of the 6G and IoT, it has been of paramount importance to cater to decent and lightweight security mechanisms in ultra-massively connected heterogeneous networks. Recently, significant efforts have been made to pave the way for the integration of physical layer security (PLS) in contemporary and futuristic networks. The primary motivation behind its deployment resides in its low complexity and ability to provide information-theoretic secure transmissions, which alleviates the complexity burden caused by implementing complex cryptographic schemes. This survey overviews the recent advancement in PLS techniques with a particular interest in its application to the Internet of Things (IoT). We review essentially recent PLS techniques aiming at ensuring message confidentiality along with node/message authentication and malicious nodes’ detection, where their corresponding application scenarios and underlying pros and cons are discussed. On top of that, we explore recent findings in the incorporation of cutting-edge technologies at the physical layer, such as non-orthogonal multiple-access, reconfigurable intelligent surfaces, joint communication and sensing, and optical wireless/Terahertz communications in boosting confidentiality and authentication at the physical layer. Lastly, promising extensions and future directions are discussed based on the quantified pros and cons of each PLS category, opening up ways for timely research directions within the topic and current/future challenges faced by PLS

Data confidentiality for IoT networks: cryptographic gaps and physical-layer opportunities

The conventional solution for providing data confidentiality is by means of encryption (a branch of cryptography). However, encryption schemes are generally designed to provide a certain level of security without necessarily taking resource consumption into account. This poses an issue for Internet of Things (IoT) devices which are limited in terms of storage capacity and computational capabilities. In this paper, we discuss the capabilities of cryptographic solutions for providing data confidentiality and we evaluate whether these solutions are appropriate for IoT networks in terms of resource consumption. Based on the identified drawbacks of cryptographic solutions, we discuss opportunities within the area of physical-layer security (PLS). Finally, we provide an overview of PLS schemes which aim to enhance data confidentiality in IoT networks

Efficient Cluster Heads Selection Based on Index-Modulation in Wireless Sensor Networks

Index-Modulation (IM) has been recently emerged as a promising direction towards improving error performance and spectral efficiency in wireless networks. To this end, IM-based Wireless Sensor Networks (IM-WSN) has been recently applied as a decision gathering scheme in clustered Wireless Sensor Networks, by which a significant improvement in the decision error rate (DER) is achieved. Later, following the same IM principle, efficient IM-WSN scheme (EIM-WSN) has been introduced, but with the emphasis on reducing the computational complexity of IM-WSN while improving the error performance. Although in these schemes cluster heads (CHs) vary dynamically, still they suffer from the unfair distribution of the CH role among nodes. As a result, nodes energy will be unequally dissipated, and hence the network lifetime will be deteriorated. In this study, aiming at balancing the CH role among cluster nodes, a new decision reporting scheme, namely index-shift, is proposed. The performance of proposed scheme is analysed in terms of DER and network lifetime and compared with the previous IM reporting schemes, IM-WSN and EIM-WSN. Analytical and simulation results show that the proposed scheme demonstrates fair distribution of CH role among all cluster nodes. This, in turn, led to extend the network lifetime up to 50% compared to other schemes, in addition to acheive DER that is better than IM-WSN and almost identical to EIM-WSN

Received signal strength based localisation in wireless sensor networks

Thousands of English as a Second Language students in Western universities strive to meet the daily challenge of preparing written assignments. These texts need to comply with the demands and preferences of their university lecturers with regard to clarity of meaning, the logical flow of ideas and the use of an academic vocabulary. However, a characteristic of ESL students’ written work is a weakness of content and a lack of logical organisation of their ideas (Roberts and Cimasko 2008). In many intensive English language programmes, students are taught to use the process-writing approach, the success of which is related to how it is perceived and introduced to the students (Lefkowitz 2009). Atkinson (2003) emphasised that the process-writing approach perceives writing to be a cognitive process that is highly private or individualistic, where writers use specific cognitive phases, such as pre-writing, drafting, and revising, to generate their text. However, writing has been increasingly recognized as a socially and culturally situated activity connecting people with each other in ways that carry particular social meanings (Hyland 2003). Despite this view of writing as a social act, Lefkowitz (2009) claimed that many English Language Programme Centres (ELPCs) superficially implement process-writing in class by aiding students in revising their essays to achieve grammatical accuracy; however the generation, formation and revision of ideas are considered to be of less importance. This study investigates the use of an electronic portfolio (TaskStream e-portfolio) in an ESL writing course as a tool to support students as they work through the key phases of the writing process. The aim was to help them adopt a consistent approach to their writing practice (self-consistency), to encourage a positive view of the value and importance of writing (self-belief), to foster a realistic appraisal of their strengths and weaknesses as writers (self-judgement), and to examine the relationship between these characteristics and the students’ overall writing performance. To that end, the study addressed four main questions: • Does utilising a web-based learning platform encourage a change in ESL learners’ writing self-belief? • Does utilising a web-based learning platform encourage a change in ESL students’ writing self-efficacy? • Does utilising a web-based learning platform encourage ESL students to consistently apply a process approach to writing? • Does utilizing a web-based learning platform lead to a change in ESL students’ overall writing performance? Using a non-equivalent pre-/post-test quasi-experimental research design, 46 ESL students from the same English Language Centre were recruited. The students were divided into a control group and an experimental group and the study ran during the spring and summer terms of 2010. A mixed methodology was used, consisting of an online questionnaire, writing sampling, online tracking and interviews in order to collect relevant data. The findings from the pre-test showed no significant differences between the participants in the two groups. The post-intervention results indicated no significant improvement among the control group’s motivational constructs and performance in writing, whereas significant differences were found in the experimental group’s writing performance and in the students’ perceived value with regard to writing, writing self-concept, writing self-efficacy and writing process approach self-consistency, following the implementation of the web-based course. However, no significant differences in ESL students’ anxiety about writing were observed. These findings suggested that e-portfolio software has the potential to promote change in ESL students’ writing self-belief and performance. Limitations of the study are discussed, implications of the findings explored, and recommendations for further research in this field are suggested.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Performance Analysis of Dual-Hop UAV-Assisted mmWave Links Considering Orientation Fluctuations

In emergency scenarios, infrastructure of wireless networks is usually damaged and becomes out of service. Therefore, Unmanned Aerial Vehicles (UAVs) have been widely nominated as an alternative to provide prompt and efficient wireless connectivity. To this end, UAV-assisted communication systems are recently being under investigation. In this paper, the focus is on UAV-assisted dual-hop links in which the source, relay and destination can be either ground-based or aerial nodes. Specifically, the paper analyzes the performance of these links in terms of the outage probability (OP) and the bit error rate (BER) considering eight different setups of dual-hop UAV-assisted links operating over the millimeter wave (mmWave) band. Unlike others, the performance analysis is conducted considering practical models of the channel fading, path loss, antennas gain and UAVs’ fluctuations. A generalized mathematical framework is followed to obtain the cumulative distribution function (CDF) and the probability density function (pdf) of the overall signal-to-noise ratio (SNR), which are utilized to characterize closed form expressions for the average OP and BER for all proposed setups. Analytical results are validated by Monte Carlo simulations which investigate the role of many setup parameters including the number of antenna elements, the fluctuation intensity, the transmit power and the modulation order. Moreover, results indicate that increasing the number of aerial entities in the link negatively affects its performance due to the impact of the fluctuations on the directional antennas in the mmWave band