IOT, Communication and Engineering

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.7	4.5	2011	16.9 Days	CHF 2400
Coatings coatings	3.4	4.7	2011	13.8 Days	CHF 2600
Energies energies	3.2	5.5	2008	16.1 Days	CHF 2600
Sensors sensors	3.9	6.8	2001	17 Days	CHF 2600
Symmetry symmetry	2.7	4.9	2009	16.2 Days	CHF 2400

25 pages, 4374 KiB

Open AccessArticle

Intelligent Drone Positioning via BIC Optimization for Maximizing LPWAN Coverage and Capacity in Suburban Amazon Environments

by Flávio Henry Cunha da Silva Ferreira, Miércio Cardoso de Alcântara Neto, Fabrício José Brito Barros and Jasmine Priscyla Leite de Araújo

Sensors 2023, 23(13), 6231; https://doi.org/10.3390/s23136231 - 07 Jul 2023

Viewed by 889

Abstract

This paper aims to provide a metaheuristic approach to drone array optimization applied to coverage area maximization of wireless communication systems, with unmanned aerial vehicle (UAV) base stations, in the context of suburban, lightly to densely wooded environments present in cities of the [...] Read more.

This paper aims to provide a metaheuristic approach to drone array optimization applied to coverage area maximization of wireless communication systems, with unmanned aerial vehicle (UAV) base stations, in the context of suburban, lightly to densely wooded environments present in cities of the Amazon region. For this purpose, a low-power wireless area network (LPWAN) was analyzed and applied. LPWAN are systems designed to work with low data rates but keep, or even enhance, the extensive area coverage provided by high-powered networks. The type of LPWAN chosen is LoRa, which operates at an unlicensed spectrum of 915 MHz and requires users to connect to gateways in order to relay information to a central server; in this case, each drone in the array has a LoRa module installed to serve as a non-fixated gateway. In order to classify and optimize the best positioning for the UAVs in the array, three concomitant bioinspired computing (BIC) methods were chosen: cuckoo search (CS), flower pollination algorithm (FPA), and genetic algorithm (GA). Positioning optimization results are then simulated and presented via MATLAB for a high-range IoT-LoRa network. An empirically adjusted propagation model with measurements carried out on a university campus was developed to obtain a propagation model in forested environments for LoRa spreading factors (SF) of 8, 9, 10, and 11. Finally, a comparison was drawn between drone positioning simulation results for a theoretical propagation model for UAVs and the model found by the measurements. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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16 pages, 4703 KiB

Open AccessArticle

Estimation of Heart Rate and Heart Rate Variability with Real-Time Images Based on Independent Component Analysis and Particle Swarm Optimization

by Te-Jen Su, Ya-Chung Hung, Tzung-Shiarn Pan, Wei-Hong Lin, Shih-Ming Wang and Yu-Cheng Lee

Appl. Sci. 2023, 13(13), 7605; https://doi.org/10.3390/app13137605 - 27 Jun 2023

Cited by 1 | Viewed by 1516

Abstract

With the rapid development of science and technology, the living habits of people have also changed from those in the past; the diet, living environment, various life pressures, etc., all overwhelm the body and mind, meaning that, nowadays, more people are suffering from [...] Read more.

With the rapid development of science and technology, the living habits of people have also changed from those in the past; the diet, living environment, various life pressures, etc., all overwhelm the body and mind, meaning that, nowadays, more people are suffering from mental illness and cardiovascular disease year on year. Therefore, a non-contact measurement of heart rate and heart rate variability (HRV) is proposed to assist physicians in diagnosing symptoms related to mental illness and cardiovascular disease. In this paper, continuous images are obtained by general network cameras with non-contact, facial feature points and regions of interest (ROI) employed to track faces and regional images; HRV parameters were analyzed with the green wavelength of RGB color space. The artifact signal is eliminated by a hybrid algorithm of independent component analysis (ICA) and particle swarming optimization (PSO). Finally, the values of heart rate and HRV are obtained with signal processes of using band-pass filter, fast Fourier transform (FFT), and power spectrum analysis in the time and frequency domains, respectively. The non-contact measurement performance of the proposed method can effectively not only avoid infection doubts and obtain heart rate and HRV quickly, but also provide better physiological parameters, root mean square error (RMSE), and mean absolute percentage error (MAPE), than those of recent published papers. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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21 pages, 18401 KiB

Open AccessArticle

Research on Channel Characteristics and Electrode Electrical Performance of Earth Current Field Information Transmission Technology

by Jingang He, Zhong Su, Zhan Xu, Zhe Kuang, Xiaowen Wen and Xin Zhou

Sensors 2023, 23(13), 5936; https://doi.org/10.3390/s23135936 - 26 Jun 2023

Viewed by 734

Abstract

Starting from the need for emergency rescue information transmission in tunnel engineering accidents, this article focuses on researching and solving the technical problems of information transmission between rescue personnel and trapped personnel after tunnel engineering collapse accidents, before and during the rescue process. [...] Read more.

Starting from the need for emergency rescue information transmission in tunnel engineering accidents, this article focuses on researching and solving the technical problems of information transmission between rescue personnel and trapped personnel after tunnel engineering collapse accidents, before and during the rescue process. The research objects are the information transmission channel and grounding electrode in the earth current field information transmission technology, and the electromagnetic characteristics of the earth medium and the electrical performance of the grounding electrode are studied and analyzed using the electromagnetic simulation software Maxwell based on finite element algorithm, establish a three-dimensional model based on the transmission of current field information of the ground electrode, analyze the effects of the electrode array, electrode depth, and radius on impedance. Research has shown that the impedance of the earth is related to the resistivity of the medium and is not a human-controllable factor. To reduce the contact impedance of an electric dipole antenna, one should start with the contact impedance of the earth electrode. The impedance of the transmitting end is an important factor affecting the efficiency of information transmission; parallel connection of multiple grounding electrodes, increasing the depth of grounding electrode penetration into the soil layer, and increasing the radius between grounding electrode pairs are all effective methods to reduce the contact impedance of electric dipole antennas, thereby improving information transmission capacity. To achieve wireless information transmission through the stratum, by appropriately selecting the operating frequency of electromagnetic waves, a certain distance of signal transmission can be achieved. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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19 pages, 8538 KiB

Open AccessArticle

Ackerman Unmanned Mobile Vehicle Based on Heterogeneous Sensor in Navigation Control Application

by Chi-Huang Shih, Cheng-Jian Lin and Jyun-Yu Jhang

Sensors 2023, 23(9), 4558; https://doi.org/10.3390/s23094558 - 08 May 2023

Cited by 1 | Viewed by 1628

Abstract

With the advancement of science and technology, the development and application of unmanned mobile vehicles (UMVs) have emerged as topics of crucial concern in the global industry. The development goals and directions of UMVs vary according to their industrial uses, which include navigation, [...] Read more.

With the advancement of science and technology, the development and application of unmanned mobile vehicles (UMVs) have emerged as topics of crucial concern in the global industry. The development goals and directions of UMVs vary according to their industrial uses, which include navigation, autonomous driving, and environmental recognition; these uses have become the priority development goals of researchers in various fields. UMVs employ sensors to collect environmental data for environmental analysis and path planning. However, the analysis function of a single sensor is generally affected by natural environmental factors, resulting in poor identification results. Therefore, this study introduces fusion technology that employs heterogeneous sensors in the Ackerman UMV, leveraging the advantages of each sensor to enhance accuracy and stability in environmental detection and identification. This study proposes a fusion technique involving heterogeneous imaging and LiDAR (laser imaging, detection, and ranging) sensors in an Ackerman UMV. A camera is used to obtain real-time images, and YOLOv4-tiny and simple online real-time tracking are then employed to detect the location of objects and conduct object classification and object tracking. LiDAR is simultaneously used to obtain real-time distance information of detected objects. An inertial measurement unit is used to gather odometry information to determine the position of the Ackerman UMV. Static maps are created using simultaneous localization and mapping. When the user commands the Ackerman UMV to move to the target point, the vehicle control center composed of the robot operating system activates the navigation function through the navigation control module. The Ackerman UMV can reach the destination and instantly identify obstacles and pedestrians when in motion. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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30 pages, 14999 KiB

Open AccessArticle

Low-Power IoT for Monitoring Unconnected Remote Areas

by Alessandro Andreadis, Giovanni Giambene and Riccardo Zambon

Sensors 2023, 23(9), 4481; https://doi.org/10.3390/s23094481 - 04 May 2023

Cited by 5 | Viewed by 2019

Abstract

This paper deals with IoT devices deployed in remote areas without terrestrial Internet connectivity. We consider connecting IoT devices on the ground to the Internet through an aerial system based on an Unmanned Aerial Vehicle (UAV) for smart agriculture and environmental monitoring. The [...] Read more.

This paper deals with IoT devices deployed in remote areas without terrestrial Internet connectivity. We consider connecting IoT devices on the ground to the Internet through an aerial system based on an Unmanned Aerial Vehicle (UAV) for smart agriculture and environmental monitoring. The UAV flying over the remote area receives data from distributed IoT devices. The transmissions between the ground sensors and the UAV are carried out via LoRa. We have proposed a synchronization protocol for the opportunistic communication of LoRa IoT devices with a gateway onboard the UAV to save node battery life. Class A LoRa nodes on the ground transmit only when the UAV is expected to pass close to them; otherwise, they stay in the sleeping state most of the time. This paper provides a detailed description of the formulation of the synchronization protocol. The UAV’s flying dynamics have been considered for characterizing its speed and the time of visibility of each IoT sensor. Our model has allowed an analytical approach that can help to determine the best settings for LoRa transmissions. Finally, experiments have been carried out to assess the path loss attenuation, and a laboratory setup of the synchronization protocol has been implemented for the preliminary validation of our scheme. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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17 pages, 6124 KiB

Open AccessReview

Industrial Internet Identity Resolution+5G Full Connection Digital Factory Research

by Dajiang Wang, Renben Jiang, Wenlei Sun, Xuedong Zhang, Cheng Lu and Yuxin Zou

Appl. Sci. 2023, 13(8), 4945; https://doi.org/10.3390/app13084945 - 14 Apr 2023

Viewed by 2040

Abstract

In this paper, in order to help improve the information capacity of modern factories, a full connection digital factory for industrial Internet identity resolution is built, and digital technology is used to perform the digital interconnection of the production equipment. The full connection [...] Read more.

In this paper, in order to help improve the information capacity of modern factories, a full connection digital factory for industrial Internet identity resolution is built, and digital technology is used to perform the digital interconnection of the production equipment. The full connection digital factory is an advanced factory with extensive connection of production units, deep integration of IT–OT, full release of data value, and improvement of the total factor productivity. This is enabled by the full integration and use of the new generation technologies represented by 5G, edge computing, and identity resolution to reach new factory level, workshop level, and production line level production scenarios. Based on the integration of infrastructure, information technology, and platform service resources, a full connection digital factory architecture is constructed. The fusion application of 5G, edge computing, and mark resolution technology in transformer discrete manufacturing digital plant is then discussed. The challenges and development trends are summarized. Finally, it is demonstrated that the full connection digital factory of identity resolution is a possible future development direction. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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39 pages, 6984 KiB

Open AccessReview

Internet of Things: A Comprehensive Overview on Protocols, Architectures, Technologies, Simulation Tools, and Future Directions

by Mohammad Mansour, Amal Gamal, Ahmed I. Ahmed, Lobna A. Said, Abdelmoniem Elbaz, Norbert Herencsar and Ahmed Soltan

Energies 2023, 16(8), 3465; https://doi.org/10.3390/en16083465 - 14 Apr 2023

Cited by 11 | Viewed by 8421

Abstract

The Internet of Things (IoT) is a global network of interconnected computing, sensing, and networking devices that can exchange data and information via various network protocols. It can connect numerous smart devices thanks to recent advances in wired, wireless, and hybrid technologies. Lightweight [...] Read more.

The Internet of Things (IoT) is a global network of interconnected computing, sensing, and networking devices that can exchange data and information via various network protocols. It can connect numerous smart devices thanks to recent advances in wired, wireless, and hybrid technologies. Lightweight IoT protocols can compensate for IoT devices with restricted hardware characteristics in terms of storage, Central Processing Unit (CPU), energy, etc. Hence, it is critical to identify the optimal communication protocol for system architects. This necessitates an evaluation of next-generation networks with improved characteristics for connectivity. This paper highlights significant wireless and wired IoT technologies and their applications, offering a new categorization for conventional IoT network protocols. It provides an in-depth analysis of IoT communication protocols with detailed technical information about their stacks, limitations, and applications. The study further compares industrial IoT-compliant devices and software simulation tools. Finally, the study provides a summary of the current challenges, along with a broad overview of the future directions to tackle the challenges, in the next IoT generation. This study aims to provide a comprehensive primer on IoT concepts, protocols, and future insights that academics and professionals can use in various contexts. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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15 pages, 3889 KiB

Open AccessArticle

Quantification of Dust Accumulation on Solar Panels Using the Contact-Characteristics-Based Discrete Element Method

by Shing-Lih Wu, Hung-Cheng Chen and Kai-Jun Peng

Energies 2023, 16(6), 2580; https://doi.org/10.3390/en16062580 - 09 Mar 2023

Cited by 1 | Viewed by 1502

Abstract

Dust comprises particles usually present in the atmosphere. The deposition of dust on the surface of the solar panel seriously affects the light transmittance, resulting in lower pow-er generation efficiency and shortening the service life of the solar panel. Therefore, it is important [...] Read more.

Dust comprises particles usually present in the atmosphere. The deposition of dust on the surface of the solar panel seriously affects the light transmittance, resulting in lower pow-er generation efficiency and shortening the service life of the solar panel. Therefore, it is important to understand the dust distribution on the surface of solar panels and discuss the influence of dust on the power generation efficiency of solar panels for the efficient prevention of dust deposition on the panel. In this study, to analyze the dust distribution on the surface of the solar panel, the discrete element method was used to establish the contact mechanics model between dust particles and the solar panel. The number of dust particles on the surface of solar panels was calculated at different solar panel inclination angles, wind speeds, and wind directions. The wind speed of 1 and 3 m/s did not affect the dust deposition significantly but the speed over 5 m/s reduced the dust particles from the surface of the solar panel. The inclination angle of 23° influenced dust deposition on the surface of the solar panel. Wind direction did not show a significant effect on dust deposition. The longer the deposition time, the more particles remained on the surface due to the increased force between the particles and the surface of the solar panel. The results from calculation and measurement from transmittance were similar with a different rate of 3.41%. Thus, the result of the proposed calculation in this study provides a basis for de-signing the solar power generation plant and decision-making on the maintenance of the solar panel. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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21 pages, 8659 KiB

Open AccessArticle

LoRaWAN Gateway Placement in Smart Agriculture: An Analysis of Clustering Algorithms and Performance Metrics

by Felipe Pinheiro Correia, Samara Ruthielle da Silva, Fabricio Braga Soares de Carvalho, Marcelo Sampaio de Alencar, Karcius Day Rosario Assis and Rodrigo Moreira Bacurau

Energies 2023, 16(5), 2356; https://doi.org/10.3390/en16052356 - 01 Mar 2023

Cited by 3 | Viewed by 2021

Abstract

The use of Wireless Sensor Networks (WSN) in smart agriculture has emerged in recent years. LoRaWAN (Long Range Wide Area Networks) is widely recognized as one of the most suitable technologies for this application, due to its capacity to transmit data over long [...] Read more.

The use of Wireless Sensor Networks (WSN) in smart agriculture has emerged in recent years. LoRaWAN (Long Range Wide Area Networks) is widely recognized as one of the most suitable technologies for this application, due to its capacity to transmit data over long distances while consuming little energy. Determining the number and location of gateways (GWs) in a production setting is one of the most challenging tasks of planning and building this type of network. Various solutions to the LoRaWAN gateway placement problem have been proposed in the literature, utilizing clustering algorithms; however, few works have compared the performance of various strategies. Considering all these facts, this paper proposes a strategy for planning the number and localization of LoRaWAN GWs, to cover a vast agricultural region. Four clustering algorithms were used to deploy the network GWs: K-Means and its three versions: Minibatch K-Means; Bisecting K-Means; and Fuzzy c-Means (FCM). As performance metrics, uplink delivery rate (ULDR) and energy consumption were used, to provide subsidies for the network designer and the client, with which to choose the best setup. A stochastic energy model was used to evaluate power consumption. Simulations were performed, considering two scenarios: Scenario 1 with lower-medium concurrence, and Scenario 2 with higher-medium concurrence. The simulations showed that the use of more than two GWs in Scenario 1 did not lead to significant improvements in ULDR and energy consumption, whereas, in Scenario 2, the suggested number of GWs was between 11 and 15. The results showed that for Scenario 1, the FCM algorithm was superior to all alternatives, regarding the ULDR and mean energy consumption, while the K-Means algorithm was superior with respect to maximum energy consumption. In relation to Scenario 2, K-Means caused the best ULDR and mean consumption, while FCM produced the lowest maximum consumption. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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18 pages, 1110 KiB

Open AccessArticle

Bio-Inspired Sleep Control for Improving the Energy Efficiency of a MEC System

by Jaesung Park and Yujin Lim

Appl. Sci. 2023, 13(4), 2620; https://doi.org/10.3390/app13042620 - 17 Feb 2023

Cited by 2 | Viewed by 1084

Abstract

The energy consumption of a multi-access edge computing (MEC) system must be reduced to save operational costs. Determining a set of active MEC servers (MECSs) that can minimize the energy consumption of the MEC system while satisfying the service delay requirements of the [...] Read more.

The energy consumption of a multi-access edge computing (MEC) system must be reduced to save operational costs. Determining a set of active MEC servers (MECSs) that can minimize the energy consumption of the MEC system while satisfying the service delay requirements of the tasks is an NP-complete problem. To solve this problem, we take a bio-inspired approach. We note that the sleep control problem of the MECS differentiates the operational mode among neighboring MECSs. Therefore, by mimicking the cell differentiation process in a biological system, we designed a distributed sleep control method. Each MECS periodically gathers the utilization and delta levels of the neighboring MECSs. Subsequently, by using the gathered information and the Delta–Notch inter-cell signaling model, a MECS autonomously decides whether to sleep. We evaluated the performance of our method through extensive simulations. Compared with a conventional method, the proposed method reduces energy consumption in a MEC system by more than

13 %

while providing a comparable service delay. In addition, our method reduces the variations in the service delay by more than

35 %

. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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19 pages, 1228 KiB

Open AccessArticle

Preference-Matched Multitask Assignment for Group Socialization under Mobile Crowdsensing

by Mingyuan Zhang, Shiyong Chen, Zihao Wei and Yucheng Wu

Sensors 2023, 23(4), 2275; https://doi.org/10.3390/s23042275 - 17 Feb 2023

Cited by 2 | Viewed by 1311

Abstract

Mobile crowdsensing (MCS) has been an emerging sensing paradigm in recent years, which uses a sensing platform for real-time processing to support various services for the Internet of Things (IoT) and promote the development of IoT. As an important component of MCS, how [...] Read more.

Mobile crowdsensing (MCS) has been an emerging sensing paradigm in recent years, which uses a sensing platform for real-time processing to support various services for the Internet of Things (IoT) and promote the development of IoT. As an important component of MCS, how to design task assignment algorithms to cope with the coexistence of multiple concurrent heterogeneous tasks in group-oriented social relationships while satisfying the impact of users’ preferences on heterogeneous multitask assignment and solving the preference matching problem under heterogeneous tasks, is one of the most pressing issues. In this paper, a new algorithm, group-oriented adjustable bidding task assignment (GO-ABTA), is considered to solve the group-oriented bilateral preference-matching problem. First, the initial leaders and their collaborative groups in the social network are selected by group-oriented collaboration, and then the preference assignment of task requesters and users is modeled as a stable preference-matching problem. Then, a tunable bidding task assignment process is completed based on preference matching under budget constraints. Finally, the individual reasonableness, stability, and convergence of the proposed algorithm are demonstrated. The effectiveness of the proposed algorithm and its superiority to other algorithms are verified by simulation results. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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20 pages, 3026 KiB

Open AccessArticle

Deep Reinforcement Learning for Edge Caching with Mobility Prediction in Vehicular Networks

by Yoonjeong Choi and Yujin Lim

Sensors 2023, 23(3), 1732; https://doi.org/10.3390/s23031732 - 03 Feb 2023

Cited by 2 | Viewed by 1687

Abstract

As vehicles are connected to the Internet, various services can be provided to users. However, if the requests of vehicle users are concentrated on the remote server, the transmission delay increases, and there is a high possibility that the delay constraint cannot be [...] Read more.

As vehicles are connected to the Internet, various services can be provided to users. However, if the requests of vehicle users are concentrated on the remote server, the transmission delay increases, and there is a high possibility that the delay constraint cannot be satisfied. To solve this problem, caching can be performed at a closer proximity to the user which in turn would reduce the latency by distributing requests. The road side unit (RSU) and vehicle can serve as caching nodes by providing storage space closer to users through a mobile edge computing (MEC) server and an on-board unit (OBU), respectively. In this paper, we propose a caching strategy for both RSUs and vehicles with the goal of maximizing the caching node throughput. The vehicles move at a greater speed; thus, if positions of the vehicles are predictable in advance, this helps to determine the location and type of content that has to be cached. By using the temporal and spatial characteristics of vehicles, we adopted a long short-term memory (LSTM) to predict the locations of the vehicles. To respond to time-varying content popularity, a deep deterministic policy gradient (DDPG) was used to determine the size of each piece of content to be stored in the caching nodes. Experiments in various environments have proven that the proposed algorithm performs better when compared to other caching methods in terms of the throughput of caching nodes, delay constraint satisfaction, and update cost. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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14 pages, 4070 KiB

Open AccessArticle

Strategies on Visual Display Terminal Lighting in Office Space under Energy-Saving Environment

by Yusen Lin, Cheng-Chen Chen and Yasser Ashraf Gandomi

Energies 2023, 16(3), 1317; https://doi.org/10.3390/en16031317 - 26 Jan 2023

Cited by 2 | Viewed by 1634

Abstract

In this work, we have studied how the vertical illuminance of the human eye position, illuminance of the horizontal work surface, and the brightness of the computer screen in the office space lighting are correlated under an energy-saving environment. This investigation was conducted [...] Read more.

In this work, we have studied how the vertical illuminance of the human eye position, illuminance of the horizontal work surface, and the brightness of the computer screen in the office space lighting are correlated under an energy-saving environment. This investigation was conducted in a full-scale laboratory that simulates an office space with 20 adults. It was found that when the indoor ambient lighting illuminance changes, the vertical illuminance of the subject’s eye position is affected accordingly, and the two factors are strongly correlated. On the other hand, when the surrounding environment is brighter and the vertical illuminance increases, the illuminance of the horizontal working surface adjusted by the subject during the visual display terminal (VDT) operation is significantly reduced. The horizontal illuminance value can even be lower than the value frequently employed in various countries around the world, since the computer screen brightness will be adjusted accordingly. Therefore, in an energy-saving environment, the illuminance of the horizontal working surface and the brightness of the computer screen adjusted by the users will vary with the ambient lighting. Especially in the current mainstream VDT operating environment and within a certain range of conditions, the interior setting can be lower than the current horizontal illuminance benchmark for additional energy conservation. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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22 pages, 753 KiB

Open AccessArticle

A Novel Low Complexity Two-Stage Tone Reservation Scheme for PAPR Reduction in OFDM Systems

by Yung-Ping Tu and Chiao-Che Chang

Sensors 2023, 23(2), 950; https://doi.org/10.3390/s23020950 - 13 Jan 2023

Cited by 4 | Viewed by 1425

Abstract

Orthogonal frequency division multiplexing (OFDM) has the characteristics of high spectrum efficiency and excellent anti-multipath interference ability. It is the most popular and mature technology currently in wireless communication. However, OFDM is a multi-carrier system, which inevitably has the problem of a high [...] Read more.

Orthogonal frequency division multiplexing (OFDM) has the characteristics of high spectrum efficiency and excellent anti-multipath interference ability. It is the most popular and mature technology currently in wireless communication. However, OFDM is a multi-carrier system, which inevitably has the problem of a high peak-to-average power ratio (PAPR), and s signal with too high PAPR is prone to distortion when passing through an amplifier due to nonlinearity. To address the troubles caused by high PAPR, we proposed an improved tone reservation (I-TR) algorithm to alleviate the above native phenomenon, which will pay some modest pre-calculations to estimate the rough proportion of peak reduction tone (PRT) to determine the appropriate output power allocation threshold then utilize a few iterations to converge to the near-optimal PAPR. Furthermore, our proposed scheme significantly outperforms previous works in terms of PAPR performance and computational complexity, such as selective mapping (SLM), partial transmission sequence (PTS), TR, tone injection (TI), etc. The simulation results show that in our proposed scheme, the PAPR is appreciably reduced by about 6.44 dB compared with the original OFDM technique at complementary cumulative distribution function (CCDF) equal to

10^{- 3}

, and the complexity of I-TR has reduced by approximately 96% compared to TR. Besides, as for bit error rate (BER), our proposed method always outperforms the original OFDM without any sacrifice. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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18 pages, 5261 KiB

Open AccessArticle

Nonlinear Adaptive Fuzzy Control Design for Wheeled Mobile Robots with Using the Skew Symmetrical Property

by Yung-Hsiang Chen and Yung-Yue Chen

Symmetry 2023, 15(1), 221; https://doi.org/10.3390/sym15010221 - 12 Jan 2023

Cited by 6 | Viewed by 1480

Abstract

This research presents a nonlinear adaptive fuzzy control method as an analytical design and a simple control structure for the trajectory tracking problem in wheeled mobile robots with skew symmetrical property. For this trajectory tracking problem in wheeled mobile robots, it is not [...] Read more.

This research presents a nonlinear adaptive fuzzy control method as an analytical design and a simple control structure for the trajectory tracking problem in wheeled mobile robots with skew symmetrical property. For this trajectory tracking problem in wheeled mobile robots, it is not easy to find an analytical adaptive fuzzy control solution due to the complicated error dynamics between the controlled wheeled mobile robots and desired trajectories. For deriving the analytical adaptive fuzzy control law of this trajectory tracking problem, a filter link is firstly adopted to find the solvable error dynamics, then the research is based on the skew symmetrical property of the transformed error dynamics. This proposed nonlinear adaptive fuzzy control solution has the advantages of low computational resource consumption and elimination of modeling uncertainties. From the results for tracking two simulation scenarios (an S type trajectory and a square trajectory), the proposed nonlinear adaptive fuzzy control method demonstrates a satisfactory trajectory tracking performance for the trajectory tracking problem in wheeled mobile robots with huge modeling uncertainties and outperforms the existing H₂ control method. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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23 pages, 3557 KiB

Open AccessArticle

Optimization of Software Test Scheduling under Development of Modular Software Systems

by Tao Huang and Chih-Chiang Fang

Symmetry 2023, 15(1), 195; https://doi.org/10.3390/sym15010195 - 09 Jan 2023

Cited by 2 | Viewed by 2182

Abstract

Software testing and debugging is a crucial part of the software development process since defective software not only incurs customer dissatisfaction but also might incur legal issues. However, the managers of a software development company cannot arbitrarily prolong their software debugging period due [...] Read more.

Software testing and debugging is a crucial part of the software development process since defective software not only incurs customer dissatisfaction but also might incur legal issues. However, the managers of a software development company cannot arbitrarily prolong their software debugging period due to their software testing budget and opportunity in the market. Accordingly, in order to propose an advantageous testing project, the managers should be aware of the influence of the testing project on cost, quality, and time to make the best decision. In this study, a new software reliability growth model (SRGM) with consideration of the testing staff’s learning effect is proposed to achieve better prediction. The methods of estimating the model’s parameters and the symmetric confidence intervals are also proposed in the study. Moreover, in the past, most of the SRGMs focused on a single software system. However, in practice, some software systems were developed using modular-based system engineering approaches. Therefore, traditional software testing work can be changed to multiple modular testing work in this scenario. Therefore, the manager can use this to dispatch multiple staff groups to perform the individual testing work simultaneously. The study proposes two mathematical programming models to handle the scheduling of modular testing work. Additionally, the design of a computerized decision support system is also proposed in the study for the application in practice. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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26 pages, 16160 KiB

Open AccessArticle

Vibration Characterization and Fault Diagnosis of a Planetary Gearbox with a Wireless Embedded Sensor

by Li-Te Huang and Jen-Yuan Chang

Appl. Sci. 2023, 13(2), 729; https://doi.org/10.3390/app13020729 - 04 Jan 2023

Cited by 3 | Viewed by 1769

Abstract

A planetary gearbox is more complex in structure and motion than a gearbox with a fixed shaft, making it difficult to monitor and make a fault diagnosis in practice. Components must be frequently inspected to avoid excessive wear, but there is no simple [...] Read more.

A planetary gearbox is more complex in structure and motion than a gearbox with a fixed shaft, making it difficult to monitor and make a fault diagnosis in practice. Components must be frequently inspected to avoid excessive wear, but there is no simple way to directly measure wear. The most direct method is to log vibration and temperature signals using external sensors. Wireless sensors offer more space advantages than a wired one, so this study developed a measurement system that features a three-axis MEMS accelerometer, temperature sensing and wireless modules that are integrated into a planetary gearbox. Along with the system, a virtual instrument (VI) utilizing graphics programming language LabVIEW was developed to acquire and display data time and frequency domains to detect the gear’s faults. To determine the root cause of vibrations in a planetary gearbox, determine the vibration signal model of amplitude modulation (AM) and frequency modulation (FM) due to gear damage and derive the characteristic frequencies of vibrations for a planetary gearbox, the characteristic frequencies and AMFM modulation were summarized in closed form. Different degrees of each gear damage were then detected in the planetary gearbox. The vibration signal model was validated by experiments to indicate the sideband around the gear meshing frequency and its feasibility for fault diagnosis of a planetary gearbox with the wireless embedded sensor. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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14 pages, 3968 KiB

Open AccessArticle

Self-Sensing Antenna for Soil Moisture: Beacon Approach

by Maja Škiljo, Zoran Blažević, Lea Dujić-Rodić, Toni Perković and Petar Šolić

Sensors 2022, 22(24), 9863; https://doi.org/10.3390/s22249863 - 15 Dec 2022

Cited by 6 | Viewed by 2765

Abstract

On the way from the Internet of things (IoT) to the Internet of underground things (IoUT) the main challenge is antenna design. The enabling technologies still rely on simple design and low cost, but the systems are more complex. The LoRa-based system combined [...] Read more.

On the way from the Internet of things (IoT) to the Internet of underground things (IoUT) the main challenge is antenna design. The enabling technologies still rely on simple design and low cost, but the systems are more complex. The LoRa-based system combined with a machine learning approach can be used for the estimation of soil moisture by using signal strength data, but for the improvement of the system performance we propose the optimization of the antenna for underground use. The soil properties are frequency-dependent and varying in time, which may cause variations in the signal wavelength and input impedance of the antenna underground. Instead of using wideband antenna design or standard helical antenna provided in LoRa module, which are typical in the IoUT research community for communication links, we propose a narrow-band antenna design for the application in soil moisture sensing. It is shown that the approach of simply matching the antenna buried in dry sand can provide a substantial signal level difference, ranging from approximately 10 dB (achieved by proof-of-concept measurements) to as much as 40 dB (calculated by a full wave simulator) in reflection coefficient when the moisture content is being increased by 20%. This can ensure more reliable radio sensing in novel sensorless technology where soil moisture information is extracted from the signal strength of a transmitting device. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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20 pages, 1003 KiB

Open AccessArticle

An Evaluation Process for IoT Platforms in Time-Sensitive Domains

by Marisol García-Valls and Eva Palomar-Cosín

Sensors 2022, 22(23), 9501; https://doi.org/10.3390/s22239501 - 05 Dec 2022

Cited by 2 | Viewed by 2347

Abstract

Determining the temporal behavior of an IoT platform is of utmost importance as IoT systems are time-sensitive. IoT platforms play a central role in the operation of an IoT system, impacting the overall performance. As a result, initiating an IoT project without the [...] Read more.

Determining the temporal behavior of an IoT platform is of utmost importance as IoT systems are time-sensitive. IoT platforms play a central role in the operation of an IoT system, impacting the overall performance. As a result, initiating an IoT project without the exhaustive knowledge of such a core software piece may lead to a failed project if the finished systems do not meet the needed temporal response and scalability levels. Despite this fact, existing works on IoT software systems focus on the design and implementation of a particular system, providing a final evaluation as the validation. This is a risky approach as an incorrect decision on the core IoT platform may involve great monetary loss if the final evaluation proves that the system does not meet the expected validation criteria. To overcome this, we provide an evaluation process to determine the temporal behavior of IoT platforms to support early design decisions with respect to the appropriateness of the particular platform in its application as an IoT project. The process defines the steps towards the early evaluation of IoT platforms, ranging from the identification of the potential software items and the determination of the validation criteria to running the experiments and obtaining results. The process is exemplified on an exhaustive evaluation of a particular mainstream IoT platform for the case of a medical system for patient monitoring. In this time-sensitive scenario, results report the temporal behavior of the platform regarding the validation parameters expressed at the initial steps. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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15 pages, 17289 KiB

Open AccessArticle

Inductive Power Transfer Battery Charger with IR-Based Closed-Loop Control

by Po-Hsuan Chen, Chaojie Li, Zhaoyang Dong and Matthew Priestley

Energies 2022, 15(21), 8319; https://doi.org/10.3390/en15218319 - 07 Nov 2022

Cited by 2 | Viewed by 1961

Abstract

A wireless battery charger with inductive power transfer (IPT) was proposed in this paper. The commonly used constant-current constant-voltage (CC-CV) charging method is accomplished by a closed-loop controlled IPT with a hybrid resonant circuit on the secondary side. A smooth transition between the [...] Read more.

A wireless battery charger with inductive power transfer (IPT) was proposed in this paper. The commonly used constant-current constant-voltage (CC-CV) charging method is accomplished by a closed-loop controlled IPT with a hybrid resonant circuit on the secondary side. A smooth transition between the CC stage and the CV stage can be made simply by swapping exactly the associated switches on resonant capacitors. The required charging voltage and current are regulated by controlling the phase-shifted angle of the high-frequency inverter on the primary side. To stabilize the charging current and voltage, a closed-loop digital controller was introduced with infrared (IR) transmission feedback. Precise regulation of the resonant inverter on a relative small ranged phase-shifted angle can be realized by two 16-bit microcontroller units (MCUs) with compact encoding and decoding techniques. A hybrid resonant inverter was designed for a 600 W prototype of the proposed IPT battery charger. Experimental results from exemplar cases have demonstrated that the battery charger can provide a stable charging current at the CC stage and then transit smoothly into the CV stage. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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18 pages, 8968 KiB

Open AccessArticle

Investigations into the Photocatalytic and Antibacterial Activity of the Nitrogen-Annealed Titanium Oxide/Silver Structure

by Jun-Kai Zhang, Kui-Shou You, Chen-Hao Huang, Pin-Jyun Shih and Day-Shan Liu

Coatings 2022, 12(11), 1671; https://doi.org/10.3390/coatings12111671 - 03 Nov 2022

Cited by 1 | Viewed by 1423

Abstract

In this study, a thin silver (Ag) layer was evaporated onto the anatase-titanium oxide (TiO_x) film. This structure was then annealed at various temperatures under nitrogen ambient to realize the Ag nanoparticles formed on the TiO_x surface. The photocatalytic activities [...] Read more.

In this study, a thin silver (Ag) layer was evaporated onto the anatase-titanium oxide (TiO_x) film. This structure was then annealed at various temperatures under nitrogen ambient to realize the Ag nanoparticles formed on the TiO_x surface. The photocatalytic activities of these TiO_x/Ag structures to decompose pollutants were determined from the rate constant while they were applied to decolorize the methylene blue (MB) solution in the presence of the UV light irradiation. According to the investigations on their surface bond configurations, the Ag nanoparticles were favorable for the transformation of the Ti⁴⁺ into the Ti³⁺ state in the TiO_x film, which functioned to prohibit the recombination of the photogenerated electron-hole-pairs on the TiO_x surface. The exposed TiO_x surface distributed over the 500 °C-annealed TiO_x/Ag structure performed an increase of about 40% in the rate constant compared to the individual TiO_x film. Moreover, this surface morphology composed of the anatase-TiO_x structures and Ag nanoparticles which was abundant in the oxide-related radical and Ag⁺ chemical state also showed a perfect antibacterial efficiency against Escherichia coli. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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17 pages, 542 KiB

Open AccessReview

Operation of Power-to-X-Related Processes Based on Advanced Data-Driven Methods: A Comprehensive Review

by Mehar Ullah, Daniel Gutierrez-Rojas, Eero Inkeri, Tero Tynjälä and Pedro H. J. Nardelli

Energies 2022, 15(21), 8118; https://doi.org/10.3390/en15218118 - 31 Oct 2022

Cited by 3 | Viewed by 2393

Abstract

This study is a systematic analysis of selected research articles about power-to-X (P2X)-related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels, which has led to a huge amount of greenhouse gas [...] Read more.

This study is a systematic analysis of selected research articles about power-to-X (P2X)-related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels, which has led to a huge amount of greenhouse gas emissions that are the source of global warming. One of the most supported actions against such a phenomenon is to employ renewable energy resources, some of which are intermittent, such as solar and wind. This brings the need for large-scale, longer-period energy storage solutions. In this sense, the P2X process chain could play this role: renewable energy can be converted into storable hydrogen, chemicals, and fuels via electrolysis and subsequent synthesis with CO₂. The main contribution of this study is to provide a systematic articulation of advanced data-driven methods and latest technologies such as the Internet of Things (IoT), big data analytics, and machine learning for the efficient operation of P2X-related processes. We summarize our findings into different working architectures and illustrate them with a numerical result that employs a machine learning model using historic data to define operational parameters for a given P2X process. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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17 pages, 3405 KiB

Open AccessArticle

A BiLSTM-Based DDoS Attack Detection Method for Edge Computing

by Yiying Zhang, Yiyang Liu, Xiaoyan Guo, Zhu Liu, Xiankun Zhang and Kun Liang

Energies 2022, 15(21), 7882; https://doi.org/10.3390/en15217882 - 24 Oct 2022

Cited by 7 | Viewed by 1922

Abstract

With the rapid development of smart grids, the number of various types of power IoT terminal devices has grown by leaps and bounds. An attack on either of the difficult-to-protect end devices or any node in a large and complex network can put [...] Read more.

With the rapid development of smart grids, the number of various types of power IoT terminal devices has grown by leaps and bounds. An attack on either of the difficult-to-protect end devices or any node in a large and complex network can put the grid at risk. The traffic generated by Distributed Denial of Service (DDoS) attacks is characterised by short bursts of time, making it difficult to apply existing centralised detection methods that rely on manual setting of attack characteristics to changing attack scenarios. In this paper, a DDoS attack detection model based on Bidirectional Long Short-Term Memory (BiLSTM) is proposed by constructing an edge detection framework, which achieves bi-directional contextual information extraction of the network environment using the BiLSTM network and automatically learns the temporal characteristics of the attack traffic in the original data traffic. This paper takes the DDoS attack in the power Internet of Things as the research object. Simulation results show that the model outperforms traditional advanced models such as Recurrent Neural Network (RNN) and Long Short Term Memory (LSTM) in terms of accuracy, false detection rate, and time delay. It plays an auxiliary role in the security protection of the power Internet of Things and effectively improves the reliability of the power grid. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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21 pages, 4020 KiB

Open AccessArticle

Soil Nitrogen Content Detection Based on Near-Infrared Spectroscopy

by Baohua Tan, Wenhao You, Shihao Tian, Tengfei Xiao, Mengchen Wang, Beitian Zheng and Lina Luo

Sensors 2022, 22(20), 8013; https://doi.org/10.3390/s22208013 - 20 Oct 2022

Cited by 10 | Viewed by 3136

Abstract

Traditional soil nitrogen detection methods have the characteristics of being time-consuming and having an environmental pollution effect. We urgently need a rapid, easy-to-operate, and non-polluting soil nitrogen detection technology. In order to quickly measure the nitrogen content in soil, a new method for [...] Read more.

Traditional soil nitrogen detection methods have the characteristics of being time-consuming and having an environmental pollution effect. We urgently need a rapid, easy-to-operate, and non-polluting soil nitrogen detection technology. In order to quickly measure the nitrogen content in soil, a new method for detecting the nitrogen content in soil is presented by using a near-infrared spectrum technique and random forest regression (RF). Firstly, the experiment took the soil by the Xunsi River in the area of Hubei University of Technology as the research object, and a total of 143 soil samples were collected. Secondly, NIR spectral data from 143 soil samples were acquired, and chemical and physical methods were used to determine the content of nitrogen in the soil. Thirdly, the raw spectral data of soil samples were denoised by preprocessing. Finally, a forecast model for the soil nitrogen content was developed by using the measured values of components and modeling algorithms. The model was optimized by adjusting the changes in the model parameters and Gini coefficient (∆Gini), and the model was compared with the back propagation (BP) and support vector machine (SVM) models. The results show that: the RF model modeling set prediction R²_C is 0.921, the RMSEC is 0.115, the test set R²_P is 0.83, and the RMSEP is 0.141; the detection of the soil nitrogen content can be realized by using a near-infrared spectrum technique and random forest algorithm, and its prediction accuracy is better than that of the BP and SVM models; using ∆ Gini to optimize the RF modeling data, the spectral information of the soil nitrogen content can be extracted, and the data redundancy can be reduced effectively. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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18 pages, 533 KiB

Open AccessArticle

Design and Analysis of Multi-User Faster-Than-Nyquist-DCSK Communication Systems over Multi-Path Fading Channels

by Mohamed Dawa, Marijan Herceg and Georges Kaddoum

Sensors 2022, 22(20), 7837; https://doi.org/10.3390/s22207837 - 15 Oct 2022

Cited by 2 | Viewed by 1546

Abstract

In this paper, we present a new multi-user chaos-based communication system using Faster-than-Nyquist sampling to achieve higher data rates and lower energy consumption. The newly designed system, designated Multi-user Faster Than Nyquist Differential Chaos Shift Keying (MU-FTN-DCSK), uses the traditional structure of Differential [...] Read more.

In this paper, we present a new multi-user chaos-based communication system using Faster-than-Nyquist sampling to achieve higher data rates and lower energy consumption. The newly designed system, designated Multi-user Faster Than Nyquist Differential Chaos Shift Keying (MU-FTN-DCSK), uses the traditional structure of Differential Chaos Shift Keying (DCSK) communication systems in combination with a filtering system that goes below the Nyquist limit for data sampling. The system is designed to simultaneously enable transmissions from multiple users through multiple sampling rates resulting in semi-orthogonal transmissions. The design, performance analysis, and experimental results of the MU-FTN-DCSK system are presented to demonstrate the utility of the newly proposed system in enabling multi-user communications and enhancing the spectral efficiency of the basic DCSK design without the addition of new blocks. The MU-FTN-DCSK system presented in this paper demonstrates spectral gains for one user of up to 23% and a combined gain of 25% for four (

U = 4

) users. In this paper, we present a proof of concept demonstrating a new degree of freedom in the design of Chaos-based communication systems and their improvement in providing wireless transmissions without complicated signal processing tools or advanced hardware designs. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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26 pages, 2758 KiB

Open AccessArticle

Natural Language Processing and Artificial Intelligence for Enterprise Management in the Era of Industry 4.0

by Pascal Muam Mah, Iwona Skalna and John Muzam

Appl. Sci. 2022, 12(18), 9207; https://doi.org/10.3390/app12189207 - 14 Sep 2022

Cited by 19 | Viewed by 10338

Abstract

Introduction: The advances in the digital era have necessitated the adoption of communication as the main channel for modern business. In the past, business negotiations, profiling, seminars, shopping, and agreements were in-person but today everything is almost digitalized. Objectives: The study aims to [...] Read more.

Introduction: The advances in the digital era have necessitated the adoption of communication as the main channel for modern business. In the past, business negotiations, profiling, seminars, shopping, and agreements were in-person but today everything is almost digitalized. Objectives: The study aims to examine how the Internet of things (IoTs) connects text-object as part of NLP and AI responding to human needs. Also, how precipitated changes in the business environment and modern applications such as NLP and AI embedded with IoTs services have changed business settings. Problem statement: As communication takes lead in the business environment, companies have developed sophisticated applications of NLP that take human desires and fulfill them instantly with the help of text, phone calls, smart records, and chatbots. The ease of communication and interaction has shown a greater influence on customer choice, desires, and needs. Modern service providers now use email, text, phone calls, smart records, and virtual assistants as first contact points for almost all of their dealings, customer inquiries, and most preferred trading channels. Method: The study uses text content as part of NLP and AI to demonstrate how companies capture customers’ insight and how they use IoTs to influence customers’ reactions, responses, and engagement with enterprise management in Industry 4.0. The “Behavior-oriented drive and influential function of IoTs on Customers in Industry 4.0” concept was used in this study to determine the influence of Industry 4.0 on customers. Results: The result indicates the least score of 12 out of 15 grades for all the measurements on a behavior-oriented drive and influential function of IoTs on customers. Conclusion: The study concluded that NLP and AI are the preferred system for enterprise management in the era of Industry 4.0 to understand customers’ demands and achieve customer satisfaction. Therefore, NLP and AI techniques are a necessity to attain business goals. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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19 pages, 4312 KiB

Open AccessArticle

A Novel Secure End-to-End IoT Communication Scheme Using Lightweight Cryptography Based on Block Cipher

by Agus Winarno and Riri Fitri Sari

Appl. Sci. 2022, 12(17), 8817; https://doi.org/10.3390/app12178817 - 01 Sep 2022

Cited by 5 | Viewed by 2868

Abstract

Personal data security is a cybersecurity trend that has captured the world’s attention. Governments, practitioners and academics are jointly building personal data security in various communication systems, including IoT. The protocol that is widely used in IoT implementation is MQTT. By default, MQTT [...] Read more.

Personal data security is a cybersecurity trend that has captured the world’s attention. Governments, practitioners and academics are jointly building personal data security in various communication systems, including IoT. The protocol that is widely used in IoT implementation is MQTT. By default, MQTT does not provide data security features in the form of data encryption. Therefore, this research was carried out on the design of Secure End-to-End Encryption MQTT with Block Cipher-Based Lightweight Cryptography. The protocol is designed by utilizing the Galantucci secret sharing scheme and a lightweight cryptographic algorithm based on a block cipher. The algorithms used include AES-128 GCM mode, GIFT-COFB, Romulus N1, and Tiny JAMBU. We tested the Secure End-to-End for MQTT protocol on the ARM M4 and ESP8266 processors. Our testing results on NodeMCU board, Tiny JAMBU have an average encryption time of 313

μ s

and an average decryption time of 327

μ s

. AES-128 GCM mode has an average encryption time of 572

μ s

and an average decryption time of 584

μ s

. GIFT-COFB has an average encryption time of 1094

μ s

and an average decryption time of 1110

μ s

. Meanwhile, Romulus N1 has an average encryption time of 2157

μ s

and an average decryption time of 2180

μ s

. On STM32L4 discovery, Tiny JAMBU had average encryption of 82

μ s

and an average decryption time of 85

μ s

. AES-128 GCM mode has an average encryption time of 163

μ s

and an average decryption time of 164

μ s

. GIFT-COFB has an average encryption time of 164

μ s

and an average decryption time of 165

μ s

. Meanwhile, Romulus N1 has an average encryption time of 605

μ s

and an average decryption time of 607

μ s

. Our experiment shows that the fastest performance is produced by Tiny JAMBU, followed by AES-128 Mode GCM, GIFT-COFB and Romulus N1. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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22 pages, 1841 KiB

Open AccessArticle

A Survey of Digital Television Interactivity Technologies

by Volnei da Silva Klehm, Rodrigo de Souza Braga and Vicente Ferreira de Lucena, Jr.

Sensors 2022, 22(17), 6542; https://doi.org/10.3390/s22176542 - 30 Aug 2022

Cited by 1 | Viewed by 2498

Abstract

This paper presents a survey of the worldwide use of Digital Television interactivity (DTVi) standards. First, we recall some concepts of first-generation interactivity middlewares released in the early 2000s, such as the European MHP (based on Java) and the Japanese BML (based on [...] Read more.

This paper presents a survey of the worldwide use of Digital Television interactivity (DTVi) standards. First, we recall some concepts of first-generation interactivity middlewares released in the early 2000s, such as the European MHP (based on Java) and the Japanese BML (based on XML). Then, we cover the new standards (emerging after 2010) that introduced the new Integrated Broadcast Broadband (IBB) model, which combines broadcast signals with a broadband interface and leverages synergies to offer high-quality, flexible, interactive and customized services and applications to viewers. Regarding IBB systems, we also cover the main aspects of their architectures and innovations introduced by this kind of technology, such as support to companion devices, e.g., smartphones, tablets, targeted advertisements, and integration with Internet-of-Things (IoT) devices. Finally, we show the current adoption of different IBB systems around the world as well as current challenges regarding IBB technologies. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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15 pages, 4764 KiB

Open AccessArticle

Backscatter-Assisted Collision-Resilient LoRa Transmission

by Fei Xiao, Wei Kuang, Huixin Dong and Yiyuan Wang

Sensors 2022, 22(12), 4471; https://doi.org/10.3390/s22124471 - 13 Jun 2022

Cited by 1 | Viewed by 1573

Abstract

Low-power wide-area networks (LPWANs), such as LoRaWAN, play an essential role and are expanding quickly in miscellaneous intelligent applications. However, the collision problem is also expanding significantly with the mass promotion of LPWAN nodes and providing collision-resilient techniques that are urgently needed for [...] Read more.

Low-power wide-area networks (LPWANs), such as LoRaWAN, play an essential role and are expanding quickly in miscellaneous intelligent applications. However, the collision problem is also expanding significantly with the mass promotion of LPWAN nodes and providing collision-resilient techniques that are urgently needed for these applications. This paper proposes BackLoRa, a lightweight method that enables collision-resilient LoRa transmission with extra propagation information provided by backscatter tags. BackLoRa uses several backscatter tags to create multipath propagation features related to the LoRa nodes’ positions and offers a lightweight algorithm to extract the feature and correctly distinguish each LoRa node. Further, BackLoRa proposes a quick-phase acquisition algorithm with low time complexity that can carry out the iterative recovery of symbols for robust signal reconstructions in low-SNR conditions. Finally, comprehensive experiments were conducted in this study to evaluate the performance of BackLoRa systems. The experimental results show th compared with the existing scheme, our scheme can reduce the symbol error rate from 65.3% to 5.5% on average and improve throughput by 15× when SNR is −20 dB. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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11 pages, 450 KiB

Open AccessArticle

Enhanced Flow Control for Low Latency in QUIC

by Sunwoo Lee and Donghyeok An

Energies 2022, 15(12), 4241; https://doi.org/10.3390/en15124241 - 09 Jun 2022

Viewed by 2242

Abstract

Low-latency communication is becoming more popular as applications that demand real-time interaction, such as autonomous mobile vehicles and tactile Internet, have recently gained prominence. In this paper, we propose a fast autotuning algorithm to support low-latency communication in the Quick UDP Internet Connection [...] Read more.

Low-latency communication is becoming more popular as applications that demand real-time interaction, such as autonomous mobile vehicles and tactile Internet, have recently gained prominence. In this paper, we propose a fast autotuning algorithm to support low-latency communication in the Quick UDP Internet Connection (QUIC) protocol. The transmission rate is adjusted by the fast autotuning based on the quantity of unused buffers. If the buffer has large free space, the receive window is quickly enlarged to increase the transmission rate and reduce the transmission delay. The fast autotuning is evaluated in this paper through extensive simulations, and the results show that the fast autotuning effectively reduces the transmission latency and increases throughput. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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23 pages, 34777 KiB

Open AccessArticle

Design and Implementation of Real-Time Localization System (RTLS) Based on UWB and TDoA Algorithm

by Fengyun Zhang, Li Yang, Yuhuan Liu, Yulong Ding, Shuang-Hua Yang and Hao Li

Sensors 2022, 22(12), 4353; https://doi.org/10.3390/s22124353 - 08 Jun 2022

Cited by 10 | Viewed by 4869

Abstract

Nowadays, accurate localization plays an essential role in many fields, such as target tracking and path planning. The challenges of indoor localization include inadequate localization accuracy, unreasonable anchor deployment in complex scenarios, lack of stability, and the high cost. So, the universal positioning [...] Read more.

Nowadays, accurate localization plays an essential role in many fields, such as target tracking and path planning. The challenges of indoor localization include inadequate localization accuracy, unreasonable anchor deployment in complex scenarios, lack of stability, and the high cost. So, the universal positioning technologies cannot meet the real application requirements scarcely. To overcome these shortcomings, a comprehensive ultra wide-band (UWB)-based real-time localization system (RTLS) is presented in this paper. We introduce the architecture of a real-time localization system, then propose a new wireless clock synchronization (WCS) scheme, and finally discuss the time difference of arrival (TDoA) algorithm. We define the time-base selection strategy for the TDoA algorithm, and we analyze the relationship between anchor deployment and positioning accuracy. The extended Kalman filter (EKF) method is presented for non-linear dynamic localization estimation, and it performs well in terms of stability and accuracy on moving targets. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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14 pages, 1832 KiB

Open AccessArticle

Vulnerability Analysis of LTE-R Train-to-Ground Communication Time Synchronization

by Yong Chen, Zhixian Zhan and Kaiyu Niu

Appl. Sci. 2022, 12(11), 5572; https://doi.org/10.3390/app12115572 - 30 May 2022

Cited by 1 | Viewed by 1617

Abstract

The time synchronization of LTE-R train-to-ground communication systems plays an important role in ensuring the safety of high-speed railways. In the LTE-R time synchronization process, existing problems, such as the time synchronization message broadcast address and LTE-R all-IP architecture, are vulnerable to attack. [...] Read more.

The time synchronization of LTE-R train-to-ground communication systems plays an important role in ensuring the safety of high-speed railways. In the LTE-R time synchronization process, existing problems, such as the time synchronization message broadcast address and LTE-R all-IP architecture, are vulnerable to attack. In order to analyze the impact of these problems, we propose a new vulnerability analysis method of LTE-R time synchronization based on stochastic Petri nets. Firstly, we construct a stochastic Petri net model of an LTE-R time synchronization process under attack. Secondly, steady-state probability expressions are obtained using the model isomorphism Markov chain. Finally, bychanging the firing rate of several key vulnerable nodes, the relationship curve between the firing rate and the steady-state probability of the clock node is obtained. Simulations show that the vulnerability of LTE-R time synchronization is most affected by the attack on eNodeB of the LTE-R base station. The results can provide a certain theoretical basis for the evolution of high-speed railway GSM-R communication systems to LTE-R. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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19 pages, 3303 KiB

Open AccessArticle

A Rapid Deployment Mechanism of Forwarding Rules for Reactive Mode SDN Networks

by Ming-Tsung Kao, Shang-Juh Kao, Hsueh-Wen Tseng and Fu-Min Chang

Symmetry 2022, 14(5), 1026; https://doi.org/10.3390/sym14051026 - 17 May 2022

Viewed by 1763

Abstract

In reactive mode software-defined networking (SDN) networks, a new initiated flow requires back-and-forth communications between the controller and the switches along the forwarding route. As SDN is getting popularly accepted, many studies have reported on how to reduce the amount of communication traffic [...] Read more.

In reactive mode software-defined networking (SDN) networks, a new initiated flow requires back-and-forth communications between the controller and the switches along the forwarding route. As SDN is getting popularly accepted, many studies have reported on how to reduce the amount of communication traffic and to release the controller’s loading. Several techniques have been proposed, such as proactive and active mode integration, MPLS adoption, and various forwarding rule installation techniques. In this paper, we adopt the idea of the tunnel penetration technique, called the tunnel boring machine in SDN or SDN-TBM, to effectively cut down the traffic between switches and the controller as well as to speed up packet delivery. Using the TBM mechanism, the communication symmetry between the controller and the switches on the path is broken and transformed into asymmetry. Only the first and last switches of each application flow need to make forwarding queries to the controller, and all intermediate switches simply forward packets consisting of the forwarding information needed to determine the next-hop switch. An M/M/1 queueing model is developed to verify the feasibility and efficiency of the proposal. Under the simulation of more than a million flows with 3–8 intermediate switches, the packet sojourn time using SDN-TBM mechanism is less than that of adopting the conventional SDN and JumpFlow model. Additionally, by adopting SDN-TBM, both the number of packet-in and packet-out packets and the controller’s loading are significantly reduced. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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10 pages, 1885 KiB

Open AccessEssay

Optimal Energy Efficiency Used DDPG in IRS-NOMA Wireless Communications

by Quanjin Liu, Jianlan Wu, Langtao Hu, Songjiao Bi, Wen Ji and Rui Yang

Symmetry 2022, 14(5), 1018; https://doi.org/10.3390/sym14051018 - 17 May 2022

Cited by 2 | Viewed by 1879

Abstract

Combining Intelligent Reflecting Surface (IRS) with Non-Orthogonal Multiple Access (NOMA) technology is a viable option for increasing communication performance. Firstly, a NOMA downlink transmission system assisted by IRS is established in this study, for maximizing its energy efficiency. Then a Deep Deterministic Policy [...] Read more.

Combining Intelligent Reflecting Surface (IRS) with Non-Orthogonal Multiple Access (NOMA) technology is a viable option for increasing communication performance. Firstly, a NOMA downlink transmission system assisted by IRS is established in this study, for maximizing its energy efficiency. Then a Deep Deterministic Policy Gradient (DDPG) algorithm with symmetric properties is used to further optimize the energy efficiency of the system by intelligently adjusting the beam-forming matrix of the access point (AP) and the phase-shift matrix of the IRS. According to the simulation results, the proposed IRS-assisted NOMA downlink network based on the DDPG algorithm presented a considerably higher energy efficiency than the orthogonal multiple access network. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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23 pages, 11251 KiB

Open AccessArticle

An Enhanced Routing and Scheduling Mechanism for Time-Triggered Traffic with Large Period Differences in Time-Sensitive Networking

by Hongrui Nie, Shaosheng Li and Yong Liu

Appl. Sci. 2022, 12(9), 4448; https://doi.org/10.3390/app12094448 - 28 Apr 2022

Cited by 7 | Viewed by 2483

Abstract

In the field of the automotive area as well as industrial control, real-time communication requires deterministic delivery with low delay and bounded jitter. Real-time communication in these networks requires transmission schedule and routing, which is an NP-hard problem. In this paper, we present [...] Read more.

In the field of the automotive area as well as industrial control, real-time communication requires deterministic delivery with low delay and bounded jitter. Real-time communication in these networks requires transmission schedule and routing, which is an NP-hard problem. In this paper, we present an offline routing and scheduling method based on integer linear programming (ILP), with a flow preprocessing step to explore the period correlation of time-triggered (TT) traffic in time-sensitive networking (TSN). First, a multiperiod flow routing and scheduling algorithm based on flow classification is proposed to improve the scheduling success rate and reduce execution time. The flow classification technique obtained a more fine-grained TT traffic classification, which can be superimposed on any routing and scheduling algorithms. Second, an adaptive period compensation scheduling algorithm based on flow classification is proposed in simple network architecture conditions. The evaluations demonstrate that the proposed algorithms improve scheduling success rate and reduce execution time compared with baseline methods in all test cases. In addition, we can adapt our different proposed algorithms in different network architecture conditions to schedule various flows with different periods and sizes. Full article

(This article belongs to the Topic IOT, Communication and Engineering)

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