Hassan H. Halawa’s research while affiliated with American University in Cairo and other places

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Publications (44)


FPGA-based Ethernet Switch for NCS with Partial Fault Tolerance
  • Conference Paper

December 2019

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36 Reads

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1 Citation

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Mohamed Refky

Recently, FPGA-based NCS applications have been widely used. Industrial environments have a lot of electromagnetic interference which may induce transient and permanent faults. As a result, Fault-Tolerant FPGA based NCS applications are required. In this paper, an NCS model composed of a combination of S2A architecture and In-Loop architecture connected to each other through Ethernet switch, is described. The S2A part of the model is an FPGA-based video sensor network which requires protection against transient faults. Several Fault-Tolerant techniques are mentioned in the literature for protection. Two Fault-Tolerant techniques are under study which are Hot Standby and Sift-Out. The fault model used is Single Event Upsets (SEUs). Dynamic Partial Recovery is used. Markov Models are used for reliability calculations. Results show that even though the Sift-Out technique is more reliable than Hot Standby, there may be situations where the difference in reliability cannot justify the extra cost.


Reliable FPGA-based Camera Sensor for NCS

June 2019

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12 Reads

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1 Citation

Networked Control Systems (NCSs) form an interesting architecture for industrial applications. They are composed of smart sensors, actuators and controllers. Also, FPGAs have recently been progressively used in industry. One of the main advantages of FPGAs is the feature of Dynamic Partial Reconfiguration (DPR) which is used to repair some failures without interrupting system operation. This paper combined both NCS and FPGAs in a new architecture that has several advantages. First, it includes an image storing capability which is very important in certain applications. Second, the architecture has several fault-tolerant features in order to prolong system lifetime. Third, even in the case of failure, raw video is never sent over the network. A case study is presented to quantify the increase in reliability of the presented system. Markov models were developed and the SHARPE package was used to compare the reliability of the proposed system to that of a comparable system in the literature; the results indicate that the proposed system is more reliable.


On the Reliability and Flexibility of FPGAs for Fault Tolerance in Sectored Networked Control Systems

June 2019

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35 Reads

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2 Citations

As Networked Control Systems grow more complex in industrial applications, moving network modules and cabling decrease overall system reliability. This paper presents an FPGA-based fault tolerance technique to reduce cabling and increase the overall reliability of such a system. A sectored sensor-to-actuator networked control system architecture with sensor-level sift-out modular redundancy is modeled and analyzed. The fault models considered in this study are Single Event Upsets and hard failures. A reliability analysis is then conducted to evaluate the reliability of each block in the system and study the overall system reliability. A generic reliability analysis is presented to investigate the flexibility of the fault tolerance technique and a case study demonstrates the reliability improvements over a system that does not utilize FPGAs and cable reduction.


Fig. 1 Proposed system architecture
Fig. 2 Greenhouse schematic
Fig. 3 Greenhouse cell
Fig. 12 Reliability versus Coverage = 100%
Reliability Markov Model with coverage = 100%

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A layered IoT architecture for greenhouse monitoring and remote control
  • Article
  • Publisher preview available

March 2019

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1,783 Reads

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74 Citations

SN Applied Sciences

Wireless Sensor Networks have been often used in the context of Greenhouse architectures. In this paper, an architecture is proposed for two Greenhouses based on Networked Control Systems. This architecture is IoT-based and built on top of switched Ethernet and Wi-Fi. Some sensors in the proposed architecture require a one-second real-time deadline. Riverbed simulations prove that there is zero packet loss and no over-delayed packets. An important contribution of this work is the design of a channel allocation scheme that prevents interference in this relatively large Greenhouse system. Another contribution of this work is the introduction of fault tolerance at the controller level. If one controller fails in one of the Greenhouses, the other controller automatically takes over the entire operation of the two-Greenhouse system. Riverbed simulations again show that this fault-tolerant system does not suffer any packet loss or over-delayed packets. Continuous Time Markov Chains are then developed to calculate the reliability as well as the steady state availability of the two-Greenhouse system. The Coverage parameter is taken into account. Finally, a case study is presented to quantitatively assess the advantage of fault tolerance in terms of downtime reduction; this is expected to be attractive especially in developing countries.

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On the Performability of Fault-Tolerant NCSs with Video Sensors: Volume 2

January 2019

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25 Reads

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1 Citation

Advances in Intelligent Systems and Computing

Smart sensors in Networked Control Systems are increasing in abundance with Industry 4.0. The use of such smart sensors can offer various advantages to a traditional networked control system. Furthermore, the utilization of such smart sensors is more realizable specifically due to the use of networked control systems, because of the abundance of bandwidth. This paper presents a networked control system, utilizing switched Ethernet, with sensors, actuators and an intelligent controller. The system also adds a smart sensor, which processes video through an onboard camera and embedded controller. The research investigated the impact of the video sensor on the system and proposed a fault-tolerant model that studies the utilization of the sensor’s onboard controller as a backup to the system’s main controller. The model is successfully simulated using Riverbed Network Modeler. Finally, a performability analysis is conducted on the proposed model.


S2A Architecture with Sift-Out at the Sensor Level: Volume 2

January 2019

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18 Reads

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1 Citation

Advances in Intelligent Systems and Computing

Networked Control Systems (NCSs) are being widely deployed to meet the demands of many critical industrial applications. This paper proposes an NCS system employing a sensor to actuator (S2A) architecture and sectoring. It is shown using Riverbed Modeler simulations that the proposed system guarantees zero packet loss with no over delayed packets using unmodified Gigabit Ethernet thus succeeding in meeting all required real-time control constraints. System performance is then quantitatively compared to similar in-loop and Sensor-to-Actuator (S2A) systems. Finally, sift-out modular redundancy is applied at the sensor level. It is shown that the system can sustain the extra network load without violating the required end-to-end control deadline and with strict zero packet loss. A case study is then carried out to calculate the expected increase in reliability in order to justify the extra cost of the sift-out system.






Citations (28)


... In today's world, automated systems are favoured over manual ones [1,4]. The Internet of Things (IoT) is a promising technology utilized for linking and controlling household devices through the Internet [5]. The field of communications technology has garnered significant interest in smart home automation systems. ...

Reference:

Implementation of a Smart Home Intruder Detection System using a Vibrometer and ESP 32 CAM
A layered IoT architecture for greenhouse monitoring and remote control

SN Applied Sciences

... The authors in [6] present a simulated study using Riverbed modeler to test the performance in term of packet loss rate, LTE response time, end-to-end delay and handover delay of manned and unmanned car connectivity using LTE communication protocol. It is stated in the paper that end-to-end delay for V2V or V2I is between 0.628ms to 1.41ms for a speed less than 37mph but in the study, free space model is used for prediction. ...

Heterogeneous ITS Architecture for Manned and Unmanned Cars in Suburban Areas
  • Citing Conference Paper
  • September 2018

... The first is the classic HSCS, which has become the dominant physical structure of bioreactor control systems since its invention (Rolf et al., 1982). Subsequently, novel fieldbus control and NCSs were developed, which can both be described as FOCSs, followed by the recently developed KBCS (Kohout et al., 2015;Van Loon, 2015;Ibrahim et al., 2018). Together with the application of smart sensors and actuators, these novel bioreactor control systems could have a profound impact on bioprocess control in the near future. ...

A High Availability Networked Control System Architecture for Precision Agriculture
  • Citing Conference Paper
  • August 2018

... Reliability, in this context, refers to the network's ability to withstand and overcome faults, including energy depletion of nodes and network failures arising from human mobility. These approaches safeguard against potential disruptions and facilitate patient mobility, particularly when patients move beyond Wi-Fi network coverage [20]. ...

Performance of fault tolerant WBAN for healthcare
  • Citing Conference Paper
  • May 2017

... The shortcoming of TMR can be solved using penta modular redundancy (5MR), which can mitigate SEUs, as well as DEUs [13,14] and follows the same methodology as that of TMR. Five identical copies of the module (M) are connected to an error detection and recovery mechanism. ...

Highly reliable controller implementation using a network-based fully reconfigurable FPGA for industrial applications
  • Citing Conference Paper
  • September 2017

... This approach can be investigated for other systems having more objectives. Additionally, neural network, fuzzy logic (Ibrahim et al., 2018;Qureshi et al., 2018;Sun et al., 2011;Massou and Boumhidi, 2017) or other optimisation techniques (Kumar and Narayan, 2017;Katal and Narayan, 2017;Singh et al., 2017b) can also be used for model order reduction. ...

Fuzzy-based Wi-Fi localisation with high accuracy using fingerprinting

International Journal of Systems Control and Communications

... Delays in response to firemen's in the delivery of information at the site inside the fire and delays in judgment at the site, which can be seen as a lack of communication means due to problems with radio equipment [1]. Frequently, fire fighters can suffer from many injuries and fatalities due to the lack of information about the fire site [2]. Thus, in order to enhance the internalization and efficiency of firefighting activities, this paper proposes the design and communication algorithm of voice recognition-based fire helmets that can deliver voice between the field crew and the control command headquarters without the operation of radio using WiFi and Bluetooth communication. ...

Enhanced data gathering for firefighting applications
  • Citing Conference Paper
  • July 2017

... The railway communication applications have different requirements that a single access technology cannot satisfy. These requirements are depicted in table 2. Railway operators have deployed diverse wireless access technologies like cellular [18], satellite [19], LPWANs [20], and Wi-Fi [21] for different needs. These technologies still need to be combined in a Multi-RAT architecture for efficient rail communication. ...

Novel system architecture for railway wireless communications
  • Citing Conference Paper
  • July 2017

... The focus of this research is to develop a new architecture where fault-tolerance is applied at the sensor level. This new architecture is based on the ones described in [14,17] with 16 S, 4 A and a supervisor. Two S and two A are wireless while the remaining 14 S and 2 A are wired. ...

Wired & wireless S2A for NCS — A case study