ISEP – CISTER – Artigos
Permanent URI for this collection
Browse
Browsing ISEP – CISTER – Artigos by Title
Now showing 1 - 10 of 357
Results Per Page
Sort Options
- 3D convolutional neural networks based automatic modulation classification in the presence of channel noisePublication . Khan, Rahim; Yang, Qiang; Ullah, Inam; Rehman, Ateeq Ur; Tufail, Ahsan Bin; NOOR, ALAM; Rehman, Abdul; Cengiz, KorhanAutomatic modulation classification is a task that is essentially required in many intelligent communication systems such as fibre-optic, next-generation 5G or 6G systems, cognitive radio as well as multimedia internet-ofthings networks etc. Deep learning (DL) is a representation learning method that takes raw data and finds representations for different tasks such as classification and detection. DL techniques like Convolutional Neural Networks (CNNs) have a strong potential to process and analyse large chunks of data. In this work, we considered the problem of multiclass (eight classes) classification of modulated signals, which are, Binary Phase Shift Keying, Quadrature Phase Shift Keying, 16 and 64 Quadrature Amplitude Modulation corrupted by Additive White Gaussian Noise, Rician and Rayleigh fading channels using 3D-CNN architectures in both frequency and spatial domains while deploying three approaches for data augmentation, which are, random zoomed in/out, random shift and random weak Gaussian blurring augmentation techniques with a cross-validation (CV) based hyperparameter selection statistical approach. Simulation results testify the performance of 10-fold CV without augmentation in the spatial domain to be the best while the worst performing method happens to be 10-fold CV without augmentation in the frequency domain and we found learning in the spatial domain to be better than learning in the frequency domain.
- 5G network as key-enabler for vehicular platooningPublication . Duarte, Paulo; Soyturk, Mujdat; Robles, Ramiro; Araújo, Marco; Yaman, Berkay; Goes, Adriano; Mendes, Bruno; Javanmardi, Gowhar; Gutiérrez Gaitán, MiguelThe future of goods transportation will rely on increased efficiency, lower risks, and diminished delays through the use of vehicle platoons that benefit from vehicular connectivity using V2X (Vehicle to Everything) applications. This article describes a system that offers the aforementioned vehicular connectivity to platoons, based on AI-enhanced 5G for resource allocation in wireless platoon intra-communications under three scenarios (latency emergency braking, platoon wireless resource management in tunnels, V2X communications interference in a traffic congestion). Demos are described for each of the scenarios, targeting different layers, starting by the PHY (physical) layer where propagation models are implemented, then a simulation-based MAC (medium access control) layer that allows the allocation of resources to the connected User Equipments (UE) and finally a management and orchestration layer capable of monitoring and managing the radio network, offering features such as network slicing management using O-RAN (Open Radio Access Network) standards.
- Active Flow Control using Dense Wireless Sensor and Actuator NetworksPublication . Robles, Ramiro; Viana, Júlio; Loureiro, João; Cintra, João; Rocha, André; Tovar, EduardoThis paper describes the design of an active flow control (AFC) system for aeronautics applications based on dense wireless sensor and actuator networks (WSANs). The objective of this AFC system is to track gradients of pressure (or wall shear stress) across the surface of the fuselage of commercial aircraft. This collected information is used to activate a set of actuators that will attempt to reduce the skin drag effect produced by the separation between laminar and turbulent flows. This is expected to be translated into increased lift-off forces, higher vehicle speeds, longer ranges and reduced fuel consumption. The paper describes the architecture of the system in the context of the European research project DEWI (dependable embedded wireless infrastructure) using the concept of the DEWI Bubble and its three-tier architecture especially designed to ensure dependability and interoperability in industrial WSANs. A system-level simulator is also proposed to model each process of the AFC system and the aeronautics DEWI Bubble infrastructure, highlighting the interactions between the network simulation and the results of the computational fluid dynamics (CFD) simulation. The key element in the proposed solution is a polygonal patch of wired sensors and actuators. This patch is provided with a wireless link to a central coordinator or access point conveniently located in the aircraft to maximize coverage to a network of distributed patches. A trade-off between scalability, size of the patches, fluid speed/viscosity, sampling sensor and actuator rates in space and time, and the capacity/delay characteristic of the wireless inter-patch and the wireline intra-patch communication technologies is also here discussed. The hybrid wireless/wired sensor and actuator network achieves great flexibility, scalability, manageability, troubleshooting, and modularity as compared to a solution exclusively based on wireline or wireless components. The final details of the prototype and results in a wind tunnel test-bed are here described, demonstrating the validity of the concept and the use of wireless technologies for aeronautical applications (flexible architecture and innovative services). Future issues regarding security, safety and trustiness of the AFC system are also briefly introduced in the context of the spin-off European project SCOTT (secure connected trusted things).
- Adaptive Fuzzy Model-free Control For 3d Trajectory Tracking Of QuadrotorPublication . Chekakta, Zakaria; Zerikat, Mokhtar; Bouzid, Yasser; Koubaa, AnisThis paper presents a novel adaptive control strategy with rejection ability for unmanned aerial vehicles (UAVs), namely fuzzy model-free control (FMFC). It is based on the model-free control (MFC) concept, where the control parameters are tuned online using fuzzy logic. The controller assumes an ultra-local model that can compensate unknown/unmodelled dynamics, uncertainties and external disturbances, ensuring a good robustness level. Moreover, the fuzzy logic system is used to tune online the proportional-derivative terms due to its heuristic aspect. These compensation and adaptation mechanisms allow ensuring good compromise robustness-performance even in the presence of disturbances. Several experiments, using RotorS Gazebo micro aerial vehicle (MAV) simulator, are provided to demonstrate the effectiveness of the proposed controller compared with other techniques. The fuzzy model-free controller shows superior performance without the time-consuming and tedious tuning task.
- Adaptive offloading for infotainment systemsPublication . Ferreira, Luís Lino; Pinho, Luís Miguel; Albano, Michele; Teixeira, CésarInfotainment applications in vehicles are currently supported both by the in-vehicle platform, as well as by user’s smart devices, such as smartphones and tablets. More and more the user expects that there is a continuous service of applications inside or outside of the vehicle, provided in any of these devices (a simple but common example is hands-free mobile phone calls provided by the vehicle platform). With the increasing complexity of ‘apps’, it is necessary to support increasing levels of Quality of Service (QoS), with varying resource requirements. Users may want to start listening to music in the smartphone, or video in the tablet, being this application transparently ‘moved’ into the vehicle when it is started. This paper presents an adaptable offloading mechanism, following a service-oriented architecture pattern, which takes into account the QoS requirements of the applications being executed when making decisions.
- Advanced sensor-based maintenance in real-world exemplary casesPublication . Albano, Michele; Lino Ferreira, Luis; Orio, Giovanni Di; Maló, Pedro; Webers, Godfried; Jantunen, Erkki; Gabilondo, Iosu; Viguera, Mikel; Papa, GregorCollecting complex information on the status of machinery is the enabler for advanced maintenance activities, and one of the main players in this process is the sensor. This paper describes modern maintenance strategies that lead to Condition-Based Maintenance. This paper discusses the sensors that can be used to support maintenance, as of different categories, spanning from common off-the-shelf sensors, to specialized sensors monitoring very specific characteristics, and to virtual sensors. This paper also presents four different real-world examples of project pilots that make use of the described sensors and draws a comparison between them. In particular, each scenario has unique characteristics requiring different families of sensors, but on the other hand provides similar characteristics on other aspects.
- An Analytical Hierarchy Process-Based Approach to Solve the Multi-Objective Multiple Traveling Salesman ProblemPublication . Trigui, Sahar; Cheikhrouhou, Omar; Koubâa, Anis; Zarrad, Anis; Youssef, HabibWe consider the problem of assigning a team of autonomous robots to target locations in the context of a disaster management scenario while optimizing several objectives. This problem can be cast as a multiple traveling salesman problem, where several robots must visit designated locations. This paper provides an analytical hierarchy process (AHP)-based approach to this problem, while minimizing three objectives: the total traveled distance, the maximum tour, and the deviation rate. The AHP-based approach involves three phases. In the first phase, we use the AHP process to define a specific weight for each objective. The second phase consists in allocating the available targets, wherein we define and use three approaches: market-based, robot and task mean allocation-based, and balanced-based. Finally, the third phase involves the improvement in the solutions generated in the second phase. To validate the efficiency of the AHP-based approach, we used MATLAB to conduct an extensive comparative simulation study with other algorithms reported in the literature. The performance comparison of the three approaches shows a gap between the market-based approach and the other two approaches of up to 30%. Further, the results show that the AHP-based approach provides a better balance between the objectives, as compared to other state-of-the-art approaches. In particular, we observed an improvement in the total traveled distance when using the AHP-based approach in comparison with the distance traveled when using a clustering-based approach.
- An efficient adaptive modulation technique over realistic wireless communication channels based on distance and SINRPublication . Khan, Rahim; Yang, Qiang; NOOR, ALAM; Altaf Khattak, Sohaib Bin; Guo, Liang; Tufail, Ahsan BinA growing trend has been observed in recent research in wireless communication systems. However, several limitations still exist, such as packet loss, limited bandwidth and inefficient use of available bandwidth that needs further investigation and research. In light of the above limitations, this paper uses adaptive modulation under various parameters, such as signal to interference plus noise ratio (SINR), and communication channel 19s distances. The primary goal is to minimize bit error rate (BER), improve throughput and utilize the available bandwidth efficiently. Additionally, the impact of Additive White Gaussian Noise (AWGN), Rayleigh and Rician fading channels on the performance of various modulation schemes are also studied. The simulation results demonstrate that our proposed technique optimally improves the BER and spectral efficiency in the long-range communication as compared to the fixed modulation schemes under the co-channel interference of surrounding base stations. The results indicate that the performance of fixed modulation schemes is suitable only either at high SINR and low distance or at low SINR and high distance values. Moreover, on the other hand, its performance was suboptimal in the entire wireless communication channel due to high distortion and attenuation. Lastly, we also noted that BER performance in the AWGN channel is better than Rayleigh and Rician channels with Rayleigh channel exhibiting poor performance than the Rician channel.
- An Enhanced WLAN Security System With FPGA Implementation for Multimedia ApplicationsPublication . Hayajneh, Thaier; Ullah, Sana; Jamil Mohd, Bassam; Balagani, KiranMaintaining a high level of data security with a low impact on system performance is more challenging in wireless multimedia applications. Protocols that are used for wireless local area network (WLAN) security are known to significantly degrade performance. In this paper, we propose an enhanced security system for a WLAN. Our new design aims to decrease the processing delay and increase both the speed and throughput of the system, thereby making it more efficient for multimedia applications. Our design is based on the idea of offloading computationally intensive encryption and authentication services to the end systems’ CPUs. The security operations are performed by the hosts’ central processor (which is usually a powerful processor) before delivering the data to a wireless card (which usually has a low-performance processor). By adopting this design, we show that both the delay and the jitter are significantly reduced. At the access point, we improve the performance of network processing hardware for real-time cryptographic processing by using a specialized processor implemented with field-programmable gate array technology. Furthermore, we use enhanced techniques to implement the Counter (CTR) Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) and the CTR protocol. Our experiments show that it requires timing in the range of 20–40 μs to perform data encryption and authentication on different end-host CPUs (e.g., Intel Core i5, i7, and AMD 6-Core) as compared with 10–50 ms when performed using the wireless card. Furthermore, when compared with the standard WiFi protected access II (WPA2), results show that our proposed security system improved the speed to up to 3.7 times.
- An Enhanced WLAN Security System With FPGA Implementation for Multimedia ApplicationsPublication . Hayajneh, Thaier; Ullah, Sana; Mohd, Bassam J.; Balagani, Kiran S.Maintaining a high level of data security with a low impact on system performance is more challenging in wireless multimedia applications. Protocols that are used for wireless local area network (WLAN) security are known to significantly degrade performance. In this paper, we propose an enhanced security system for a WLAN. Our new design aims to decrease the processing delay and increase both the speed and throughput of the system, thereby making it more efficient for multimedia applications. Our design is based on the idea of offloading computationally intensive encryption and authentication services to the end systems’ CPUs. The security operations are performed by the hosts’ central processor (which is usually a powerful processor) before delivering the data to a wireless card (which usually has a low-performance processor). By adopting this design, we show that both the delay and the jitter are significantly reduced. At the access point, we improve the performance of network processing hardware for real-time cryptographic processing by using a specialized processor implemented with field-programmable gate array technology. Furthermore, we use enhanced techniques to implement the Counter (CTR) Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) and the CTR protocol. Our experiments show that it requires timing in the range of 20–40 μs to perform data encryption and authentication on different end-host CPUs (e.g., Intel Core i5, i7, and AMD 6-Core) as compared with 10–50 ms when performed using the wireless card. Furthermore, when compared with the standard WiFi protected access II (WPA2), results show that our proposed security system improved the speed to up to 3.7 times.