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20 pages, 1885 KiB

Open AccessArticle

A Dynamic Topology Optimization Method for Tactical Edge Networks Based on Virtual Backbone Networks

by Zhixiang Kong, Zilong Jin and Chengsheng Pan

Sensors 2024, 24(17), 5489; https://doi.org/10.3390/s24175489 - 24 Aug 2024

Viewed by 637

To address the issues of low survivability and communication efficiency in wireless sensor networks caused by frequent node movement or damage in highly dynamic and high-mobility battlefield environments, we propose a dynamic topology optimization method based on a virtual backbone network. This method [...] Read more.

To address the issues of low survivability and communication efficiency in wireless sensor networks caused by frequent node movement or damage in highly dynamic and high-mobility battlefield environments, we propose a dynamic topology optimization method based on a virtual backbone network. This method involves two phases: topology reconstruction and topology maintenance, determined by a network coverage threshold. When the coverage falls below the threshold, a virtual backbone network is established using a connected dominating set (CDS) and non-backbone node optimization strategies to reconstruct the network topology, quickly restore network connectivity, effectively improve network coverage, and optimize the network structure. When the coverage is above the threshold, a multi-CDS scheduling algorithm and slight position adjustments of non-backbone nodes are employed to maintain the network topology, further enhancing network coverage with minimal node movement. Simulations demonstrate that this method can improve coverage and optimize network structure under different scales of network failures. Under three large-scale failure operational scenarios where the network coverage threshold was set to 80%, the coverage was enhanced by 26.12%, 15.88%, and 13.36%, and in small-scale failures, the coverage was enhanced by 7.55%, 4.90% and 7.84%. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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26 pages, 11764 KiB

Open AccessArticle

Beacon Success Rate versus Gateway Density in Sub-GHz Sensor Networks

by Başak Can, Bora Karaoğlu, Srikar Potta, Franklin Zhang, Artur Balanuta, Muhammed Faruk Gencel, Uttam Bhat, Johnny Huang, Pooja Patankar, Shruti Makharia, Radhakrishnan Suryanarayanan, Arvind Kandhalu and Vinay Sagar Krishnamurthy Vijaya Shankar

Sensors 2023, 23(23), 9530; https://doi.org/10.3390/s23239530 - 30 Nov 2023

Viewed by 1195

Abstract

Multiple Gateways (GWs) provide network connectivity to Internet of Things (IoT) sensors in a Wide Area Network (WAN). The End Nodes (ENs) can connect to any GW by discovering and acquiring its periodic beacons. This provides GW diversity, improving coverage area. However, simultaneous [...] Read more.

Multiple Gateways (GWs) provide network connectivity to Internet of Things (IoT) sensors in a Wide Area Network (WAN). The End Nodes (ENs) can connect to any GW by discovering and acquiring its periodic beacons. This provides GW diversity, improving coverage area. However, simultaneous periodic beacon transmissions among nearby GWs lead to interference and collisions. In this study, the impact of such intra-network interference is analyzed to determine the maximum number of GWs that can coexist. The paper presents a new collision model that considers the combined effects of the Medium Access Control (MAC) and Physical (PHY) layers. The model takes into account the partial overlap durations and relative power of all colliding events. It also illustrates the relationship between the collisions and the resulting packet loss rates. A performance evaluation is presented using a combination of analytical and simulation methods, with the former validating the simulation results. The system models are developed from experimental data obtained from field measurements. Numerical results are provided with Gaussian Frequency Shift Keying (GFSK) modulation. This paper provides guidance on selecting GFSK modulation parameters for low bit-rate and narrow-bandwidth IoT applications. The analysis and simulation results show that larger beacon intervals and frequency hopping help in reducing beacon loss rates, at the cost of larger beacon acquisition latency. On the flip side, the gateway discovery latency reduces with increasing GW density, thanks to an abundance of beacons. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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22 pages, 763 KiB

Open AccessArticle

An Efficient Early-breaking-estimation and Tree-splitting Missing RFID Tag Identification Protocol

by Mingqiu Fan, Lijuan Zhang, Lei Lei and Chunni Yu

Sensors 2023, 23(23), 9318; https://doi.org/10.3390/s23239318 - 21 Nov 2023

Cited by 1 | Viewed by 985

Abstract

Retailers grapple with inventory losses primarily due to missing items, prompting the need for efficient missing tag identification methods in large-scale RFID systems. Among them, few works considered the effect of unexpected unknown tags on the missing tag identification process. With the presence [...] Read more.

Retailers grapple with inventory losses primarily due to missing items, prompting the need for efficient missing tag identification methods in large-scale RFID systems. Among them, few works considered the effect of unexpected unknown tags on the missing tag identification process. With the presence of unknown tags, some missing tags may be falsely identified as present. Thus, the system’s reliability is hardly guaranteed. To resolve these challenges, we propose an efficient early-breaking-estimation and tree-splitting-based missing tag identification (ETMTI) protocol for large-scale RFID systems. ETMTI employs innovative early-breaking-estimation and deactivation methods to swiftly handle unknown tags. Subsequently, a tree-splitting-based missing tag identification method is proposed, employing a B-ary splitting tree, to rapidly identify missing tags. Additionally, a bit-tracking response strategy is implemented to reduce processing time. Theoretical analysis is conducted to determine optimal parameters for ETMTI. Simulation results illustrate that our proposed ETMTI protocol significantly outperforms benchmark methods, offering a shorter processing time and a lower false negative rate. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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13 pages, 2628 KiB

Open AccessArticle

Bistability of AlGaAs/GaAs Resonant-Tunneling Diodes Heterostructural Channel

by Natalia Vetrova, Evgeny Kuimov, Vladimir Sinyakin, Sergey Meshkov, Mstislav Makeev and Vasiliy Shashurin

Sensors 2023, 23(18), 7977; https://doi.org/10.3390/s23187977 - 19 Sep 2023

Cited by 2 | Viewed by 1194

Abstract

This paper presents an effective compact model of current transfer for the estimation of hysteresis parameters on the volt-ampere characteristics of resonant-tunneling diodes. In the framework of the compact model, the appearance of hysteresis is explained as a manifestation of internal bistability due [...] Read more.

This paper presents an effective compact model of current transfer for the estimation of hysteresis parameters on the volt-ampere characteristics of resonant-tunneling diodes. In the framework of the compact model, the appearance of hysteresis is explained as a manifestation of internal bistability due to interelectronic interaction in the channel of the resonant-tunneling structure. Unlike the models based on the method of equivalent circuits, the interelectronic interaction in the compact model is taken into account using the concentration parameter. Model validation allowed us to confirm the high accuracy of the model not only at the initial section of the volt-ampere characteristics, but also at the hysteresis parameters traditionally predicted with low accuracy, namely the loop width (∆ < 0.5%) and contrast (∆ < 7%). Thus, it is concluded that the models are promising for integration into systems for synthesizing the electrical characteristics of resonant-tunneling diodes. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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25 pages, 959 KiB

Open AccessArticle

Optimal Scheduling in General Multi-Queue System by Combining Simulation and Neural Network Techniques

by Dmitry Efrosinin, Vladimir Vishnevsky and Natalia Stepanova

Sensors 2023, 23(12), 5479; https://doi.org/10.3390/s23125479 - 10 Jun 2023

Cited by 4 | Viewed by 1755

Abstract

The problem of optimal scheduling in a system with parallel queues and a single server has been extensively studied in queueing theory. However, such systems have mostly been analysed by assuming homogeneous attributes of arrival and service processes, or Markov queueing models were [...] Read more.

The problem of optimal scheduling in a system with parallel queues and a single server has been extensively studied in queueing theory. However, such systems have mostly been analysed by assuming homogeneous attributes of arrival and service processes, or Markov queueing models were usually assumed in heterogeneous cases. The calculation of the optimal scheduling policy in such a queueing system with switching costs and arbitrary inter-arrival and service time distributions is not a trivial task. In this paper, we propose to combine simulation and neural network techniques to solve this problem. The scheduling in this system is performed by means of a neural network informing the controller at a service completion epoch on a queue index which has to be serviced next. We adapt the simulated annealing algorithm to optimize the weights and the biases of the multi-layer neural network initially trained on some arbitrary heuristic control policy with the aim to minimize the average cost function which in turn can be calculated only via simulation. To verify the quality of the obtained optimal solutions, the optimal scheduling policy was calculated by solving a Markov decision problem formulated for the corresponding Markovian counterpart. The results of numerical analysis show the effectiveness of this approach to find the optimal deterministic control policy for the routing, scheduling or resource allocation in general queueing systems. Moreover, a comparison of the results obtained for different distributions illustrates statistical insensitivity of the optimal scheduling policy to the shape of inter-arrival and service time distributions for the same first moments. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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14 pages, 1537 KiB

Open AccessArticle

An Anomaly Intrusion Detection for High-Density Internet of Things Wireless Communication Network Based Deep Learning Algorithms

by Emad Hmood Salman, Montadar Abas Taher, Yousif I. Hammadi, Omar Abdulkareem Mahmood, Ammar Muthanna and Andrey Koucheryavy

Sensors 2023, 23(1), 206; https://doi.org/10.3390/s23010206 - 25 Dec 2022

Cited by 17 | Viewed by 2558

Abstract

Telecommunication networks are growing exponentially due to their significant role in civilization and industry. As a result of this very significant role, diverse applications have been appeared, which require secured links for data transmission. However, Internet-of-Things (IoT) devices are a substantial field that [...] Read more.

Telecommunication networks are growing exponentially due to their significant role in civilization and industry. As a result of this very significant role, diverse applications have been appeared, which require secured links for data transmission. However, Internet-of-Things (IoT) devices are a substantial field that utilizes the wireless communication infrastructure. However, the IoT, besides the diversity of communications, are more vulnerable to attacks due to the physical distribution in real world. Attackers may prevent the services from running or even forward all of the critical data across the network. That is, an Intrusion Detection System (IDS) has to be integrated into the communication networks. In the literature, there are numerous methodologies to implement the IDSs. In this paper, two distinct models are proposed. In the first model, a custom Convolutional Neural Network (CNN) was constructed and combined with Long Short Term Memory (LSTM) deep network layers. The second model was built about the all fully connected layers (dense layers) to construct an Artificial Neural Network (ANN). Thus, the second model, which is a custom of an ANN layers with various dimensions, is proposed. Results were outstanding a compared to the Logistic Regression algorithm (LR), where an accuracy of 97.01% was obtained in the second model and 96.08% in the first model, compared to the LR algorithm, which showed an accuracy of 92.8%. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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25 pages, 6072 KiB

Open AccessArticle

Dynamic Smoothing, Filtering and Differentiation of Signals Defining the Path of the UAV

by Aleksey S. Antipov, Julia G. Kokunko, Svetlana A. Krasnova and Victor A. Utkin

Sensors 2022, 22(23), 9472; https://doi.org/10.3390/s22239472 - 4 Dec 2022

Cited by 4 | Viewed by 1820

Abstract

On the example of a control system for an unmanned aerial vehicle, we consider the problems of filtering, smoothing and restoring derivatives of reference action signals. These signals determine the desired spatial path of the plant at the first approximation. As a rule, [...] Read more.

On the example of a control system for an unmanned aerial vehicle, we consider the problems of filtering, smoothing and restoring derivatives of reference action signals. These signals determine the desired spatial path of the plant at the first approximation. As a rule, researchers have considered these problems separately and have used different methods to solve each of them. The paper aims to develop a unified approach that provides a comprehensive solution to mentioned problems. We propose a dynamic admissible path generator. It is constructed as a copy of the canonical control plant model with smooth and bounded sigmoid corrective actions. For the deterministic case, a synthesis procedure has been developed, which ensures that the output variables of the generator track a non-smooth reference signal. Moreover, it considers the constraints on the velocity and acceleration of the plant. As a result, the generator variables produce a naturally smoothed spatial curve and its derivatives, which are realizable reference actions for the plant. The construction of the generator does not require exact knowledge of the plant parameters. Its dynamic order is less than that of the standard differentiators. We confirm the effectiveness of the approach by the results of numerical simulation. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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12 pages, 3353 KiB

Open AccessArticle

On the Problem of State Recognition in Injection Molding Based on Accelerometer Data Sets

by Julian Brunthaler, Patryk Grabski, Valentin Sturm, Wolfgang Lubowski and Dmitry Efrosinin

Sensors 2022, 22(16), 6165; https://doi.org/10.3390/s22166165 - 17 Aug 2022

Cited by 3 | Viewed by 2106

Abstract

The last few decades have been characterised by a very active application of smart technologies in various fields of industry. This paper deals with industrial activities, such as injection molding, where it is required to monitor continuously the manufacturing process to identify both [...] Read more.

The last few decades have been characterised by a very active application of smart technologies in various fields of industry. This paper deals with industrial activities, such as injection molding, where it is required to monitor continuously the manufacturing process to identify both the effective running time and down-time periods. Supervised machine learning algorithms are developed to recognize automatically the periods of the injection molding machines. The former algorithm uses directly the features of the descriptive statistics, while the latter one utilizes a convolutional neural network. The automatic state recognition system is equipped with an 3D-accelerometer sensor whose datasets are used to train and verify the proposed algorithms. The novelty of our contribution is that accelerometer data-based machine learning models are used to distinguish producing and non-producing periods by means of recognition of key steps in an injection molding cycle. The first testing results show the approximate overall balanced accuracy of 72–92% that illustrates the large potential of the monitoring system with the accelerometer. According to the ANOVA test, there are no sufficient statistical differences between the comparative algorithms, but the results of the neural network exhibit higher variances of the defined accuracy metrics. Full article

(This article belongs to the Special Issue Internet of Mobile Things and Wireless Sensor Networks)

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