Enhanced Precision Time Synchronization for Wireless Sensor Networks

Time synchronization in wireless sensor networks (WSNs) is a fundamental issue for the coordination of distributed entities and events. Nondeterministic latency, which may decrease the accuracy and precision of time synchronization can occur at any point in the network layers. Specially, random back-off by channel contention leads to a large uncertainty. In order to reduce the large nondeterministic uncertainty from channel contention, we propose an enhanced precision time synchronization protocol in this paper. The proposed method reduces the traffic needed for the synchronization procedure by selectively forwarding the packet. Furthermore, the time difference between sensor nodes increases as time advances because of the use of a clock source with a cheap crystal oscillator. In addition, we provide a means to maintain accurate time by adopting hardware-assisted time stamp and drift correction. Experiments are conducted to evaluate the performance of the proposed method, for which sensor nodes are designed and implemented. According to the evaluation results, the performance of the proposed method is better than that of a traditional time synchronization protocol

Tests of IEEE 1588-based synchronization system in substation

Kao metoda sinkronizacije, IEEE1588 norma je primijenjena u trafostanici, to bi trebalo osigurati ispitanu i provjerenu sinkronizacijku točnost i čvora interoperabilnosti. Metoda sveobuhvatnog testiranja za IEEE1588 se predlaže u ovom radu. Nadalje, IEEE1588 platforma testiranja ure izgrađena je kao podrška predložene metode ispitivanja. Na temelju analize sinkronizacije pogreške ure i metode ispitivanja načela značajke, ocjenjene su točnost i stabilnost glavne ure i pomoćne ure. Drugo, ispitivanje usklađeno s normom za usvajanje odziva značajke je postignuto dizajniranjem konkretnog slučaju, na osnovi navedenog, a potom analizirati pojedinosti provedbe sukladnosti. Prema zahtjevima ispitivanja, dizajnirana je testna osnovna ploča. Konačno, pokus utemeljen na uređajima transfostanice proveden je uporabom IEEE1588 platforme testiranja ure. Izvedivost predloženih metoda dodatno je potvrđena s rezultatima testiranja.As a synchronization method, IEEE1588 standard has been applied in substation, it should be tested and verified ensure synchronization accuracy and node interoperability. A comprehensive testing method for the IEEE1588 is proposed in this paper. Furthermore, IEEE1588 clock testing platform is built to support the proposed testing method. Based on the analysis of the clock synchronization error and the performance testing principle method, the accuracy and stability of master clock and slave clock were evaluated. Secondly, the conformance testing to adopt performance response was achieved by designed specific case, based on the above, and then to analyse the conformance implementation details. According to testing requirements, test bed designed. Finally, the experiment based on substation devices was carried out using the IEEE1588 clock testing platform. The feasibility of the proposed methods was further verified with the testing results

Supporting and Securing Personal Mobile Devices Within an Existing Information Technology Environment

Personal mobile devices are becoming integrated into the daily operations of business. Managers are realizing that employees who are allowed to use personal mobile devices to access corporate information systems may reduce costs as users buy their own devices. The problem was that managers have a limited understanding of the need to secure or support personal mobile devices. The purpose of this survey study was to examine the relationship between employees\u27 desire to use personal mobile devices and corporation needs for security and support. Hypotheses were tested by examining the relationships between the requirement to support and secure personal mobile devices as the independent variables and the desire to use personal mobile devices as the dependent variable. The theoretical framework for the study included the IT product life-cycle management theory, IT security-management theory, and IT strategic-management theory. Survey data were collected from a convenience sample of 108 employees at the study-site organization from an estimated population of 170. Basic linear regression analyses performed found a correlation coefficient of 0.905 indicating the variables are highly correlated. This finding indicates that if personal mobile devices are given access to corporate information systems, then support and security will be necessary for successful operations. If the relationship between internal factors and operational success is clearly documented, organizations may be able to use the data to justify incorporating personal mobile devices within their own corporate information system to reduce costs, improve productivity, and increase employee satisfaction, thereby making a positive contribution to society

Enhancing graph-routing algorithm for industrial wireless sensor networks

Industrial Wireless Sensor Networks (IWSNs) are gaining increasing traction, especially in domains such as the Industrial Internet of Things (IIoT), and the Fourth Industrial Revolution (Industry 4.0). Devised for industrial automation, they have stringent requirements regarding data packet delivery, energy consumption balance, and End-to-End Transmission (E2ET) time. Achieving effective communication is critical to the fulfilment of these requirements and is significantly facilitated by the implementation of graph-routing – the main routing method in the Wireless Highway Addressable Remote Transducer (WirelessHART), which is the global standard of IWSNs. However, graph-routing in IWSN creates a hotspot challenge resulting from unbalanced energy consumption. This issue stems from the typical configuration of WirelessHART paths, which transfers data packets from sensor nodes through mesh topology to a central system called the Network Manager (NM), which is connected to a network gateway. Therefore, the overall aim of this research is to improve the performance of IWSNs by implementing a graph-routing algorithm with unequal clustering and optimisation techniques. In the first part of this thesis, a basic graph-routing algorithm based on unequal clustering topologies is examined with the aim of helping to balance energy consumption, maximise data packet delivery, and reduce the number of hops in the network. To maintain network stability, the creation of static clusters is proposed using the WirelessHART Density-controlled Divide-and-Rule (WDDR) topology. Graph-routing can then be built between Cluster Heads (CHs), which are selected according to the maximum residual energy rate between the sensor nodes in each static cluster. Simulation results indicate that graph-routing with the WDDR topology and probabilistic unequal clustering outperforms mesh topology, even as the network density increased, despite isolated nodes found in the WDDR topology. The second part of this thesis focuses on using the Covariance-Matrix Adaptation Evolution Strategy (CMA-ES) algorithm. This addresses the three IWSN requirements that form the focus of this research, by proposing three single-objective graph-routing paths: minimum distance (PODis), maximum residual energy (POEng), and minimum end-to-end transmission time (POE2E). The research also adapts the CMA-ES to balance multiple objectives, resulting in the Best Path of Graph-Routing with a CMA-ES (BPGR-ES). Simulation results show that the BPGR-ES effectively balances IWSN requirements, but single-objective paths of graph-routing does not achieve balanced energy consumption with mesh topology, resulting in a significant reduction in the efficiency of the network. Therefore, the third part of this thesis focuses on an Improvement of the WDDR (IWDDR) topology to avoid isolated nodes in the static cluster approaches. The IWDDR topology is used to evaluate the performance of the single-objective graph-routing paths (PODis, POEng, and POE2E). The results show that in IWDDR topology, single-objective graph-routing paths result in more balanced energy consumption

Enhanced Precision Time Synchronization for Wireless Sensor Networks

Time synchronization in wireless sensor networks (WSNs) is a fundamental issue for the coordination of distributed entities and events. Nondeterministic latency, which may decrease the accuracy and precision of time synchronization can occur at any point in the network layers. Specially, random back-off by channel contention leads to a large uncertainty. In order to reduce the large nondeterministic uncertainty from channel contention, we propose an enhanced precision time synchronization protocol in this paper. The proposed method reduces the traffic needed for the synchronization procedure by selectively forwarding the packet. Furthermore, the time difference between sensor nodes increases as time advances because of the use of a clock source with a cheap crystal oscillator. In addition, we provide a means to maintain accurate time by adopting hardware-assisted time stamp and drift correction. Experiments are conducted to evaluate the performance of the proposed method, for which sensor nodes are designed and implemented. According to the evaluation results, the performance of the proposed method is better than that of a traditional time synchronization protocol