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  • 1.
    Afshar, Sara Zargari
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Koroorian, Fereidon
    ABB, Västerås, Sweden.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Granlund, Anna
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Investigating Alternatives for System Architectures to Enhance Discrete Manufacturing2019In: International Journal of Distributed Sensor Networks, ISSN 1550-1329, E-ISSN 1550-1477, Vol. 15, no 8, article id 1550147719868668Article in journal (Refereed)
    Abstract [en]

    This article investigates the possibility of advancing discrete manufacturing using system architectures that are developed for Collaborative Process Automation Systems. Collaborative Process Automation System is a technology that has the potential to achieve production excellence for process industry. However, not much attention has been paid on using the architectures based on Collaborative Process Automation Systems for discrete manufacturing domains. In this article, we propose a base architecture consisting of three layers, and we discuss various alternatives to make the communications among the layers. We consider legacy components in the proposal, in contrast to most of the related works. In order to show the practicality of the proposed alternatives, we present an example that has been implemented in an ongoing project at ABB Robotics in Sweden.

  • 2.
    Aglianò, Simone
    et al.
    University of Catania, Catania, Italy.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lo Bello, Lucia
    University of Catania, Catania, Italy.
    Resource Management and Control in Virtualized SDN Networks2018In: CSI International Symposium on Real-Time and Embedded Systems and Technologies REST'18, 2018, p. 47-53Conference paper (Refereed)
    Abstract [en]

    Software defined networking and network virtual-ization are widely considered promising techniques for reducing the complexity of network management in many contexts that require high Quality of Service (QoS) and the support for heterogeneous architectures. In this paper we address a network architecture, here called a virtualized SDN network, that combines the benefits of SDN and virtualization. To cope with the demand for efficiently sharing a platform among several services, here a resource management mechanism to reserve and control network resources among various services in the virtualized SDN networks is proposed. The mechanism is implemented on an SDN controller and a set of experiments show the effectiveness of the proposed approach.

  • 3.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Multi-Hop Real-Time Communication over Switched Ethernet Technology2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Switched Ethernet technology has been introduced to be exploited in real-time communication systems due to its features such as its high throughput and wide availability, hence being a cost-effective solution. Many real-time switched Ethernet protocols have been developed, preserving the profits of traditional Ethernet technology, to overcome the limitations imposed by using commercially available (COTS) switches. These limitations mainly originate from the non-deterministic behavior of the Ethernet switches inherent in the use of FIFO queues and a limited number of priority levels.

     

    In our research we focus on two particular real-time communication technologies, one based on COTS Ethernet switches named the FTT-SE architecture and the other using a modified Ethernet switch called the HaRTES architecture. Both architectures are based on a master-slave technique supporting different and temporally isolated traffic types including real-time periodic, real-time sporadic and non-real-time traffic. Also, they provide mechanisms implementing adaptivity as a response to the requirements imposed by dynamic real-time applications. Nevertheless, the two mentioned architectures were originally developed for a simple network consisting of a single switch, and they were lacking support for multi-hop communication. In industrial applications, multi-hop communication is essential as the networks comprise a high number of nodes, that is far beyond the capability of a single switch.

     

    In this thesis, we study the challenges of building multi-hop communication using the FTT-SE and the HaRTES architectures. We propose different architectures to provide multi-hop communication while preserving the key characteristics of the single-switch architecture such as timeliness guarantee, resource efficiency, adaptivity and dynamicity. We develop a response time analysis for each proposed architecture and we compare them to assess their corresponding benefits and limitations. Further, we develop a simulation tool to evaluate the solutions.

  • 4.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Real-Time Communication over Switched Ethernet with Resource Reservation2016Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Due to the need for advanced computer-controlled functionality in distributed embedded systems the requirements on network communication are becoming overly intricate. This dissertation targets the requirements that are concerned with real-time guarantees, run-time adaptation, resource utilization and flexibility during the development. The Flexible Time-Triggered Switched Ethernet (FTT-SE) and Hard Real-Time Ethernet Switching (HaRTES) network architectures have emerged as two promising solutions that can cater for these requirements. However, these architectures do not support multi-hop communication as they are originally developed for single-switch networks. This dissertation presents a fundamental contribution in multi-hop real-time communication over the FTT-SE and HaRTES architectures targeting the above mentioned requirements. It proposes and evaluates various solutions for scheduling and forwarding the traffic through multiple switches in these architectures. These solutions preserve the ability of dynamic adaptation without jeopardizing real-time properties of the architectures. Moreover, the dissertation presents schedulability analyses for the timeliness verification and evaluation of the proposed solutions as well as several protocols to support run-time adaptation in the multi-hop communication. Finally, the work led to an end-to-end resource reservation framework, based on the proposed multi-hop architectures, to support flexibility during the development of the systems. The efficiency of the proposed solutions is evaluated on various case studies that are inspired from industrial systems.

  • 5.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    MTU Assignment in a Master-Slave Switched Ethernet Network2013Conference paper (Refereed)
    Abstract [en]

    In this paper, we investigate the problem of selecting the Maximal Transmission Unit (MTU) size that maximizes the schedulability of real-time messages. We focus on a bandwidth-efficient master-slave switched Ethernet protocol, namely the FTT-SE protocol. We propose an algorithm to find the MTU for each message in order to maximize the schedulability of the messages. Moreover, we evaluate our proposed algorithm and we show that setting the MTU for messages using the algorithm increases the schedulability of messages compared with assigning the MTU to the maximum value that the protocol can support.

  • 6.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. University of Porto, Porto, Portugal .
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    MTU Configuration for Real-Time Switched Ethernet Networks2016In: Journal of systems architecture, ISSN 1383-7621, E-ISSN 1873-6165, Vol. 70, p. 15-25Article in journal (Refereed)
    Abstract [en]

    In this paper, we show that in real-time switched Ethernet networks reducing the Maximum Transmission Unit (MTU) size may cause an increase or decrease in the response time of messages. This contradicting behavior arises an optimization problem for configuring the MTU size. We formulate the optimization problem in the context of the multi-hop HaRTES architecture, which is a hard real-time Ethernet protocol. As part of the solution, we propose a search-based algorithm to achieve optimum solutions. We modify the algorithm by presenting two techniques to reduce the search space. Then, we propose a heuristic algorithm with a pseudo-polynomial time complexity based on the search-based algorithm. We perform several experiments, and we show that the proposed heuristic results in an improvement regarding messages response times, compared with configuring the MTU to the maximum or minimum values. Moreover, we show in small network configurations that the heuristic performs as good as the search-based algorithm in many cases.

  • 7.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Performance Analysis of Master-Slave Multi-Hop Switched Ethernet Networks2013In: Proceedings of the 8th IEEE International Symposium on Industrial Embedded Systems, SIES 2013, 2013, p. 280-289Conference paper (Refereed)
    Abstract [en]

    There is an increasing trend towards using switched Ethernet in real-time distributed systems due to features like absence of collisions and high throughput. Nevertheless, a few problems persist, in particular related to priority inversion and limited length in queues. In this paper we focus on a protocol which uses a master-slave technique over standard switched Ethernet in order to overcome such problems, namely FTT-SE protocol. We present an improved response time analysis for such a network and we compare, analytically and with simulations, the results achieved with Network Calculus on a worst-case scenario. We show that our proposed response time analysis gives tighter bounds compared to Network Calculus. Moreover, we compare the performance of different solutions to scale the FTT-SE protocol with respect to the bandwidth utilization. Finally, we propose a new architecture to improve the average performance of master-slave switched Ethernet networks.

  • 8.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Malardalen Univ, Malardalen Real Time Res Ctr MRTC, POB 883, SE-72123 Vasteras, Sweden..
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Malardalen Univ, Malardalen Real Time Res Ctr MRTC, POB 883, SE-72123 Vasteras, Sweden..
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Malardalen Univ, Malardalen Real Time Res Ctr MRTC, POB 883, SE-72123 Vasteras, Sweden..
    SEtSim: A modular simulation tool for switched Ethernet networks2016In: Journal of systems architecture, ISSN 1383-7621, E-ISSN 1873-6165, Vol. 65, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Using high bandwidth network technologies in real-time applications, for example in automotive systems, is rapidly increasing. In this context, switched Ethernet-based protocols are becoming more popular due to their features such as providing a collision-free domain for transmission of messages. Moreover, switched Ethernet is a mature technology. Several protocols based on switched Ethernet have been proposed over the years, tuned for time critical applications. However, research for improving the features and performance of these protocols is still on-going. In order to evaluate the performance of early stage proposed protocols, the mathematical analysis and/or experiments are required. However, performing an experiment for complex network topologies with a large set of messages is not effortless. Therefore, using a simulation based approach for evaluating a protocol's performance and/or properties is highly useful. As a response to this we have developed a simulator, called SEtSim, for switched Ethernet networks. SEtSim is developed based on Simulink, and it currently supports different network topologies of the FIT-SE protocol as well as Ethernet AVB protocol. However, the kernel of SEtSim is designed such that it is possible to add and integrate other switched Ethernet-based protocols. In this paper, we describe the design of SEtSim and we show its scalability.

  • 9.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering. Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    SEtSim: A Modular Simulation Tool for Switched Ethernet Networks2014Report (Other academic)
    Abstract [en]

    Using high bandwidth network technologies in real-time applications, for example in automotive systems, is rapidly increasing. In this context, switched Ethernet-based protocols are becoming more popular due to their features such as providing a collision-free domain for transmission of messages. Moreover, switched Ethernet is a mature technology. Several protocols based on switched Ethernet have been proposed over the years, tuned for time critical applications. However, research for improving the features and performance of these protocols is still on-going. In order to evaluate the performance of early stage proposed protocols, the mathematical analysis and/or experiments are required. However, performing an experiment for complex network topologies with a large set of messages is not effortless. Therefore, using a simulation based approach for evaluating a protocol's performance and/or properties is highly useful. As a response to this we have, based on Simulink, developed a simulator, called SEtSim, for switched Ethernet networks. SEtSim currently supports different network topologies of the FTT-SE protocol, a master-slave protocol designed for standard Ethernet switches, as well as Ethernet AVB protocol. However, the kernel of SEtSim is designed such that it is possible to add and integrate other switched Ethernet-based protocols. In this paper, we describe the design of SEtSim and we show its scalability.

  • 10.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    The Design and Implementation of a Simulator for Switched Ethernet Networks2012In: 3rd International Workshop on Analysis Tools andMethodologies for Embeddedand Real-time Systems / [ed] Tommaso Cucinotta and Giuseppe Lipari, 2012, p. 57-62Conference paper (Refereed)
    Abstract [en]

    In the context of Switched Ethernet, the Flexible Time-Triggered Switched Ethernet protocol (FTT-SE) was proposed to overcome the limitations and related problems of using COTS switches in real-time networks, such as overflow of switch queues due to uncontrolled arrival of packets. Although the FTT-SE protocol has been validated by several experiments on real applications, evaluation of different architectures as well as evaluation of large scale networks is not straightforward. Therefore, a simulator to evaluate different network architectures based on the FTT-SE protocol is useful. In this paper we present such a simulator. We address the extended FTT-SE protocol using multiple switches and we present a modular simulator based on Simulink/Matlab to visualize message transmissions and to evaluate end-to-end delay bounds of messages.

  • 11.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Almeida, Luis
    University of Porto.
    Marau, Ricardo
    University of Porto.
    A Compact Approach to Clustered Master-Slave Ethernet Networks2012In: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, 2012, p. 157-160Conference paper (Refereed)
    Abstract [en]

    Ethernet switches are increasingly used in real-time distributed systems as a technical solution to guarantee the timeliness in communications. However, there are still limitations related to real-time behavior caused by the limited number of priority levels and the possibility of memory overruns with consequent message losses. These limitations can be eliminated using a master/slave technique such as proposed by the FTT paradigm. This led to the FTT-SE protocol that schedules transmissions centrally in a master node. While this protocol has already been well studied and investigated for small networks with a single switch, its extension to larger networks is still an open issue. In this paper we propose a compact clustered solution to scale the FTT-SE protocol to networks of multiple switches by organizing the network in sub-networks composed of one master and one switch each and which can be connected directly, without bridges. This paper also shows how the timeliness of the traffic can still be enforced. The validation is currently on-going.

  • 12.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pedreiras, Paulo
    University of Aveiro, Portugal.
    Bril, Reinder J.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Reduced Buffering Solution for Multi-Hop HaRTES Switched Ethernet Networks2014In: The 20th IEEE International Conference on embedded and Real-Time Computing Systems and Applications RTCSA'14, 2014, p. Article number 6910504-Conference paper (Refereed)
    Abstract [en]

    In the context of switched Ethernet networks, multi-hop communication is essential as the networks in industrial applications comprise a high amount of nodes, that is far beyond the capability of a single switch. In this paper, we focus on multi-hop communication using HaRTES switches. The HaRTES switch is a modified Ethernet switch that provides real-time traffic scheduling, dynamic Quality-of-Service and temporal isolation between real-time and non-real-time traffic. Herein, we propose a method, called Reduced Buffering Scheme, to conduct the traffic through multiple HaRTES switches in a multi-hop HaRTES architecture. In order to enable the new scheduling method we propose to modify the HaRTES switch structure. Moreover, we develop a response time analysis for the new method. We also compare the proposed method with a method previously proposed, called Distributed Global Scheduling, based on their traffic response times. We show that, the new method forwards all types of traffic including the highest, the medium and the lowest priority, faster than the previous method in most of the cases. Furthermore, we show that the new method performs even better for larger networks compared with the previous one.

  • 13.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Rodriguez-Navas, Guillermo
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Universitat de les Illes Balears, Spain.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Implementing a Clock Synchronization Protocol on a Multi-Master Switched Ethernet Network2013Conference paper (Refereed)
    Abstract [en]

    The interest to use Switched Ethernet technologies in real-time communication is increasing due to its absence of collisions when transmitting messages. Nevertheless, using COTS switches affect the timeliness guarantee inherent in potentially overflowing internal FIFO queues. In this paper we focus on a solution, called the FTT-SE protocol, which is developed based on a master-slave technique. Recently, an extension of the FTT-SE protocol has been proposed where the transmission of messages are controlled using multiple master nodes. In order to guarantee the correctness of the protocol, the masters should be timely synchronized. Therefore, in this paper we investigate using a clock synchronization protocol, based on the IEEE 1588 standard, among master nodes and we study the effects of this protocol on the network performance. In addition, we present a formal verification of this solution by means of model checking to prove the correctness of the FTT-SE protocol when the clock synchronization protocol is applied.

  • 14.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Du, Yong
    Almeida, L.
    University of Porto, Porto, Portugal .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dynamic reconfiguration in HaRTES switched ethernet networks2016In: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, 2016, article id Article number 7496510Conference paper (Refereed)
    Abstract [en]

    The ability of reconfiguring a system during runtime is essential for dynamic real-time applications in which resource usage is traded online for quality of service. The HaRTES switch, which is a modified Ethernet switch, holds this ability for the network resource, and at the same time it provides hard real-time support for both periodic and sporadic traffic. Although the HaRTES switch technologically caters this ability, a protocol to actually perform the dynamic reconfiguration is missing in multi-hop HaRTES networks. In this paper we introduce such a protocol that is compatible with the traffic scheduling method used in the architecture. We prove the correctness of the protocol using a model checking technique. Moreover, we conduct a set of simulation experiments to show the performance of the protocol and we also show that the reconfiguration process is terminated within a bounded time. 

  • 15.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Khalilzad, Nima
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IS (Embedded Systems).
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sander, Ingo
    Royal Institute of Technology, Sweden.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Designing End-to-end Resource Reservations in Predictable Distributed Embedded Systems2017In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 53, no 6, p. 916-956Article in journal (Refereed)
    Abstract [en]

    Contemporary distributed embedded systems in many domains have become highly complex due to ever-increasing demand on advanced computer controlled functionality. The resource reservation techniques can be effective in lowering the software complexity, ensuring predictability and allowing flexibility during the development and execution of these systems. This paper proposes a novel end-to-end resource reservation model for distributed embedded systems. In order to support the development of predictable systems using the proposed model, the paper provides a method to design resource reservations and an end-to-end timing analysis. The reservation design can be subjected to different optimization criteria with respect to runtime footprint, overhead or performance. The paper also presents and evaluates a case study to show the usability of the proposed model, reservation design method and end-to-end timing analysis. 

  • 16.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Liu, Meng
    Mälardalen University, School of Innovation, Design and Engineering.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering.
    Mifdaoui, A.
    University of Toulouse, France.
    Almeida, L.
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering.
    Worst-case delay analysis of master-slave switched ethernet networks2012In: Proceeings of the 2nd International Workshop on Worst-Case Traversal Time: Proceeding, 2012, p. 15-21Conference paper (Refereed)
    Abstract [en]

    Switched Ethernet is increasingly used in real-time communication due to its intrinsic features such as micro segmentation and high throughput. However, COTS switches may impose long blocking times due to their FIFO queues and can also experience buffer overflow in outgoing queues due to uncontrolled packets arrival. The FTT-SE protocol uses a Master-Slave technique to overcome the COTS switch limitations in real-time applications. Recently, we extended the protocol for large scale networks and in this paper we present the worst-case delay analysis using the Network Calculus formalism for such a network. Moreover, we assess the end-to-end delay of traffic with simulation concluding that the obtained analytical results present a good match with the observed delays, providing uppers bounds that vary between 0% and 50% above the maximum measured values. © 2012 ACM.

  • 17.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    End-to-end Resource Reservations in Distributed Embedded Systems2016In: Proceedings - 2016 IEEE 22nd International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2016, 2016, p. 1-11, article id 7579921Conference paper (Refereed)
    Abstract [en]

    The resource reservation techniques provide effective means to lower the software complexity, ensure predictability and allow flexibility during the development and execution of complex distributed embedded systems. In this paper we propose a new end-to-end resource reservation model for distributed embedded systems. The model is comprehensive in such a way that it supports end-to-end resource reservations on distributed transactions with various activation patterns that are commonly used in industrial control systems. The model allows resource reservations on processors and real-time network protocols. We also present timing analysis for the distributed embedded systems that are developed using the proposed model. The timing analysis computes the end-to-end response times as well as delays such as data age and reaction delays. The presented analysis also supports real-time networks that can autonomously initiate transmissions. Such networks are not supported by the existing analyses. We also include a case study to show the usability of the model and end-to-end timing analysis with resource reservations.

  • 18.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    End-to-end Resource Reservation Model2016Manuscript (preprint) (Other academic)
  • 19.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Patti, Gaetano
    University of Catania, Italy.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Alderisi, Giuliana
    University of Catania, Italy.
    Lo Bello, Lucia
    University of Catania, Italy.
    Schedulability Analysis of Ethernet Audio Video Bridging Networks with Scheduled Traffic Support2017In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 53, no 4, p. 526-577Article in journal (Refereed)
    Abstract [en]

    The IEEE Audio Video Bridging (AVB) technology is nowadays under consideration in several automation domains, such as, automotive, avionics, and industrial communications. AVB offers several benefits, such as open specifications, the existence of multiple providers of electronic components, and the real-time support, as AVB provides bounded latency to real-time traffic classes. In addition to the above mentioned properties, in the automotive domain, comparing with the existing in-vehicle networks, AVB offers significant advantages in terms of high bandwidth, significant reduction of cabling costs, thickness and weight, while meeting the challenging EMC/EMI requirements. Recently, an improvement of the AVB protocol, called the AVB ST, was proposed in the literature, which allows for supporting scheduled traffic, i.e., a class of time-sensitive traffic that requires time-driven transmission and low latency. In this paper, we present a schedulability analysis for the real-time traffic crossing through the AVB ST network. In addition, we formally prove that, if the bandwidth in the network is allocated according to the AVB standard, the schedulability test based on response time analysis will fail for most cases even if, in reality, these cases are schedulable. In order to provide guarantees based on analysis test a bandwidth over-reservation is required. In this paper, we propose a solution to obtain a minimized bandwidth over-reservation. To the best of our knowledge, this is the first attempt to formally spot the limitation and to propose a solution for overcoming it. The proposed analysis is applied to both the AVB standard and the AVB ST. The analysis results are compared with the results of several simulative assessments, obtained using OMNeT++, on both automotive and industrial case studies. The comparison between the results of the analysis and the simulation ones shows the effectiveness of the analysis proposed in this work.

  • 20.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pedreiras, P.
    University of Aveiro, Aveiro, Portugal .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, L.
    University of Porto, Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Evaluation of dynamic reconfiguration architecture in multi-hop switched ethernet networks2014In: 19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014, 2014, p. Article number 7005322-Conference paper (Refereed)
    Abstract [en]

    On-the-fly adaptability and reconfigurability are recently becoming an interest in real-time communications. To assure a continued real-time behavior, the admission control with a quality-of-service mechanism is required, that screen all adaptation and reconfiguration requests. In the context of switched Ethernet networks, the FTT-SE protocol provides adaptive real-time communication. Recently, we proposed two methods to perform the online reconfiguration in multi-hop FTT-SE architectures. However, the methods lack the experimental evaluation. In this paper, we evaluate both methods in terms of the reconfiguration time. 

  • 21.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pedreiras, P.
    DETI/IT, University of Aveiro, Aveiro, Portugal .
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bril, Reinder J.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Technische Universiteit Eindhoven (TU/e), Netherlands .
    Almeida, L.
    Technische Universiteit Eindhoven (TU/e), Netherlands .
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Response time analysis of multi-hop HaRTES Ethernet Switch networks2014In: IEEE Int. Workshop Factory Commun. Syst. Proc. WFCS, 2014Conference paper (Refereed)
    Abstract [en]

    In this paper we focus on micro-segmented switched-Ethernet networks with HaRTES switches. HaRTES switches provide synchronous and asynchronous real-time traffic scheduling, dynamic Quality-of-Service adaptation and transparent integration of real-time and non-real-time nodes. Herein we investigate the challenges of connecting multiple HaRTES switches in order to build multi-hop communication and we propose a method, named Distributed Global Scheduling, to handle the traffic forwarding in such an architecture while preserving the unique properties of the single HaRTES switch case. Moreover, we develop a response time analysis for the method. We also evaluate the level of pessimism embodied in the anal-ysis. Finally, we show the applicability of the proposed method in an industrial setting by applying it in an automotive case study.

  • 22.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pedreiras, Paulo
    University of Aveiro, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dynamic Reconfiguration in Multi-Hop Switched Ethernet Networks2014In: ACM SIGBED Review. Special Issue on 6th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2014), ISSN 1551-3688, Vol. 11, no 3, p. 62-65Article in journal (Refereed)
    Abstract [en]

    The FTT-SE protocol provides adaptive real-time communication on Ethernet networks. To assure a continued real-time behavior, FTT-SE integrates admission control with a quality-of-service mechanism, which screen all adaptation and reconfiguration requests, accepting only those that do not compromise the system timeliness. The adaptability and reconfigurability have been deeply studied in the case of single switch FTT-SE architectures, whereas the extension of that for the multi-hop FTT-SE architecture was not yet investigated. Therefore, in this paper we study the challenges of enabling dynamic reconfiguration in multi-hop FTT-SE networks, we propose two methods (one centralized and one distributed) and we present a qualitative comparison between them.

  • 23.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pedreiras, Paulo
    University of Aveiro, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    University of Porto, Portugal.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Supporting Multi-Hop Communications with HaRTES Ethernet Switches2013Conference paper (Refereed)
    Abstract [en]

    In this paper we identify the challenges of multi-hop communication when using a micro-segmented switched-Ethernet protocol with enhanced HaRTES switches. The HaRTES architecture has been explored in the scope of single-switch topology, and provides dynamic virtual channels that can be composed hierarchically and provide bounded latency together with temporal isolation. Herein we propose two different solutions regarding the traffic forwarding in multi-switch architectures, while maintaining the unique properties of the single HaRTES switch case. In the first approach, the traffic is buffered and scheduled sequentially in each hop. In the second solution the traffic is scheduled once and forwarded immediately through multiple switches without buffering. In this paper we present a brief comparison of both approaches and we report on the on-going work towards effective support to real-time communications in dynamic and complex Cyber-Physical Systems.

  • 24.
    Ashjaei, Mohammad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. MRTC Malardalen Univ, Vasteras, Sweden..
    Silva, Luis
    DETI IT Univ Aveiro, Aveiro, Portugal..
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. MRTC Malardalen Univ, Vasteras, Sweden..
    Pedreiras, Paulo
    DETI IT Univ Aveiro, Aveiro, Portugal..
    Bril, Reinder J.
    Tech Univ Eindhoven TU E, Eindhoven, Netherlands..
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. MRTC Malardalen Univ, Vasteras, Sweden.;IT DEEC Univ Porto, Oporto, Portugal..
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. MRTC Malardalen Univ, Vasteras, Sweden..
    Improved Message Forwarding for Multi-Hop HaRTES Real-Time Ethernet Networks2016In: Journal of Signal Processing Systems, ISSN 1939-8018, E-ISSN 1939-8115, Vol. 84, no 1, p. 47-67Article in journal (Refereed)
    Abstract [en]

    Nowadays, switched Ethernet networks are used in complex systems that encompass tens to hundreds of nodes and thousands of signals. Such scenarios require multi-switch architectures where communications frequently occur in multiple hops. In this paper we investigate techniques to allow efficient multi-hop communication using HaRTES switches. These are modified Ethernet switches that provide real-time traffic scheduling, dynamic bandwidth management and temporal isolation between real-time and non-real-time traffic. This paper addresses the problem of forwarding traffic in HaRTES networks. Two methods have been recently proposed, namely Distributed Global Scheduling (DGS) that buffers traffic between switches, and Reduced Buffering Scheme (RBS), that uses immediate forwarding. In this paper, we discuss the design and implementation of RBS within HaRTES and we carry out an experimental validation with a prototype implementation. Then, we carry out a comparison between RBS and DGS using worst-case response time analysis and simulation. The comparison clearly establishes the superiority of RBS concerning end-to-end response times. In fact, with sample message sets, we achieved reductions in end-to-end delay that were as high as 80 %.

  • 25.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Bengtsson, Marcus
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation. IS (Embedded Systems).
    Enhancing Smart Maintenance Management Using Fog Computing Technology2017In: 2017 International Conference on Industrial Engineering and Engineering Management IEEM, 2017, p. 1561-1565Conference paper (Refereed)
    Abstract [en]

    In order for factories to stay competitive in the current open global market, there should be efforts to put on optimizing the value stream of producing goods. Within this context, Industrial Internet of Things (IIoT) has been emerged as a technology aiming at achieving high productivity performance in manufacturing. A smart manufacturing approach also requires a smart maintenance management as it plays a crucial role in securing the productivity. IIoT applications are traditionally completed by the cloud computing technology to serve the required services. In this paper, we argue that maintenance processes have requirements that cannot be accomplished by solely the cloud computing technology. We identify several of these requirements. Then, we propose a platform using the fog computing technology, as a recently raised technology in IIoT, to enhance the smart maintenance management. We also discuss the ability of the platform in fulfilling the identified requirements.

  • 26.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Clegg, Kester
    Univ York, York, N Yorkshire, England..
    Corneo, Lorenzo
    Uppsala Univ, Uppsala, Sweden..
    Hawkins, Richard
    Univ York, York, N Yorkshire, England..
    Jaradat, Omar
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Gulisano, Vincenzo Massimiliano
    Chalmers Univ, Gothenburg, Sweden..
    Nikolakopoulos, Yiannis
    Chalmers Univ, Gothenburg, Sweden..
    Service Level Agreements for Safe and Configurable Production Environments2018In: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), IEEE , 2018, p. 1252-1255Conference paper (Refereed)
    Abstract [en]

    This paper focuses on Service Level Agreements (SLAs) for industrial applications that aim to port some of the control functionalities to the cloud. In such applications, industrial requirements should be reflected in SLAs. In this paper, we present an approach to integrate safety-related aspects of an industrial application to SLAs. We also present the approach in a use case. This is an initial attempt to enrich SLAs for industrial settings to consider safety aspects, which has not been investigated thoroughly before.

  • 27.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Clegg, Kester
    University of York, UK.
    Corneo, Lorenzo
    Uppsala University, Sweden.
    Hawkins, Richard
    University of York, UK.
    Jaradat, Omar
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Gulisano, Vincenzo
    Chalmers University of Technology, Göteborg, Sweden.
    Nikolakopoulos, Yiannis
    Chalmers University of Technology, Göteborg, Sweden.
    Service Level Agreements for Safe and Configurable Production Environments2018In: International Conference on Emerging Technologies and Factory Automation - Work in Progress Session ETFA-WiP'18, 2018, p. 1252-1255, article id 8502568Conference paper (Refereed)
    Abstract [en]

    This paper focuses on Service Level Agreements (SLAs) for industrial applications that aim to port some of the control functionalities to the cloud. In such applications, industrial requirements should be reflected in SLAs. In this paper, we present an approach to integrate safety-related aspects of an industrial application to SLAs. We also present the approach in a use case. This is an initial attempt to enrich SLAs for industrial settings to consider safety aspects, which has not been investigated thoroughly before.

  • 28.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Khalilzad, Nima
    Qamcom Research and Technology, Stockholm, Sweden.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Modeling, Designing and Analyzing Resource Reservations in Distributed Embedded Systems2018In: Real-Time Modelling and Processing for Communication Systems / [ed] Springer, Springer , 2018, p. 203-256Chapter in book (Other academic)
  • 29.
    Ashjaei, Seyed Mohammad Hossein
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lundbäck, John
    Arcticus Systems AB, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Sweden.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Sweden.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Modeling and Timing Analysis of Vehicle Functions Distributed over Switched Ethernet2017In: IECON 2017 - 43RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, 2017, p. 8419-8424Conference paper (Refereed)
    Abstract [en]

    This paper proposes an approach to model switched Ethernet communication within a model- and component-based software development framework for vehicular distributed embedded systems. The paper also presents a method to extract the network timing model from the systems that use switched Ethernet networks. In order to provide a proof of concept, an existing industrial component model and its tool suite, namely RCM and Rubus-ICE respectively, are extended by implementing the modeling technique, the timing model extraction method and response-time analysis of the Ethernet AVB protocol. The extensions to RCM are backward compatible with the modeling and end-to-end timing analysis of traditional in-vehicle networks and legacy (previously developed) vehicular distributed embedded systems. Furthermore, the paper discusses the implementation and test strategy used in this work. Finally, the usability of the modeling approach and implemented timing analysis is demonstrated by modeling and time analyzing a vehicular application case study with the extended component model and tool suite.

  • 30.
    Cao, Jingyue
    et al.
    Eindhoven University of Technology, Netherlands.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Cuijpers, Pieter J.L.
    Eindhoven University of Technology, Netherlands.
    J. Bril, Reinder
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lukkien, Johan
    Eindhoven University of Technology, Netherlands.
    An Independent yet Efficient Analysis of Bandwidth Reservation for Credit-based Shaping in Ethernet TSN2018In: International Workshop on Factory Communication Systems WFCS'18, Imperia, Italy, 2018, p. 1-10Conference paper (Refereed)
    Abstract [en]

    Ethernet TSN is an upcoming communication standard for industrial distributed embedded systems with high demands on bandwidth and traffic delay. In this paper, we present and prove an improved analysis to determine bandwidth reservations for credit based shapers in a single Ethernet TSN switch. We compare this new analysis, which is based on eligible intervals, to the state-of-the-art bandwidth reservation analysis based on busy periods through experiments. Despite its low complexity and the independence of the knowledge of the interfering traffic, the results show an improvement of efficiency, i.e., a decrease of the required bandwidth, for the new analysis.

  • 31.
    Causevic, Aida
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lisova, Elena
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashgar, Syed Usman
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    On incorporating security parameters in service level agreements2019In: CLOSER 2019 - Proceedings of the 9th International Conference on Cloud Computing and Services Science, SciTePress , 2019, p. 48-57Conference paper (Refereed)
    Abstract [en]

    With development of cloud computing new ways for easy, on-demand, Internet-based access to computing resources have emerged. In such context a Service Level Agreement (SLA) enables contractual agreements between service providers and users. Given an SLA, service users are able to establish trust in that the service outcome corresponds to what they have demanded during the service negotiation process. However, an SLA provides a limited support outside of basic Quality of Service (QoS) parameters, especially when it comes to security. We find security as an important factor to be included in adjusting an SLA according to user defined objectives. Incorporating it in an SLA is challenging due to difficulty to provide complete and quantifiable metrics, thus we propose to focus on a systematic way of addressing security using the security process. In this paper we investigate ways in which security might be incorporated already in the service negotiation process and captured in an SLA. We propose a corresponding process to develop and maintain an SLA that considers both design-, and run-time. To demonstrate the approach we built upon the existing SLAC language and extend its syntax to support security. An example of a service being provided with security guarantees illustrates the concept.

  • 32.
    Danielsson, Jakob
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sörensen, Thomas
    Westermo Teleindustri AB, Västerås, Sweden.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Performance Evaluation of Network Convergence Time Measurement Techniques2017In: International Conference on Emerging Technologies And Factory Automation ETFA'17, 2017, p. 1-7Conference paper (Refereed)
    Abstract [en]

    In this paper we evaluate solutions that provide measurements for the network convergence time in switched Ethernet networks when links failures happen. We evaluate three solutions to measure the network convergence time in a faulty situation. Compared to the commercially available solutions, our proposals are cost-effective, portable, and open source. Thus, they are easy to deploy on many testbeds. We show the performance of the solutions by measuring different metrics including jitter, network convergence time and packet loss during the network recovery time. Our measurements indicate that it is possible to accurately measure the network convergence time using a packet sender which does not suffer interference from the overlying operating system. Furthermore, we noticed that the packet sniffer TShark did not suffer from kernel interrupts from overlying operating systems.

  • 33. Ghaderi, Adnan
    et al.
    Daneshtalab, Masoud
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Loni, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Design challenges in hardware development of time-sensitive networking: A research plan2019In: CEUR Workshop Proceedings, CEUR-WS , 2019, Vol. 2457Conference paper (Refereed)
    Abstract [en]

    Time-Sensitive Networking (TSN) is a set of ongoing projects within the IEEE standardization to guarantee timeliness and low-latency communication based on switched Ethernet for industrial applications. The huge demand is mainly coming from industries where intensive data transmission is required, such as in the modern vehicles where cameras, lidars and high-bandwidth modern sensors are connected. The TSN standards are evolving over time, hence the hardware needs to change depending upon the modifications. In addition, high performance hardware is required to obtain a full benefit from the standards. In this paper, we present a research plan for developing novel techniques to support a parameterized and modular hardware IP core of the multi-stage TSN switch fabric in VHSIC (Very High Speed Integrated Circuit) Hardware Description Language (VHDL), which can be deployed in any Field-Programmable-Gate-Array (FPGA) devices. We present the challenges on the way towards the mentioned goal. 

  • 34.
    Girs, Svetlana
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Designing a Bandwidth Management Scheme for Heterogeneous Virtualized Networks2018In: International Conference on Emerging Technologies and Factory Automation - Work in Progress Session ETFA-WiP'18, 2018, p. 1079-1082, article id 8502450Conference paper (Refereed)
    Abstract [en]

    With envisioned increased density and complexity of future industrial networks, software defined networking (SDN) and network virtualization are considered to be promising techniques for network organization and management. Thus, in this paper we look at heterogeneous software defined networks consisting of several virtual slices and present a bandwidth control algorithm, which is designed to provide control over shared bandwidth both in wired and wireless parts of the network. The designed algorithm has been implemented in real hardware and in this paper we present the initial test results.

  • 35.
    Girs, Svetlana
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Designing a Bandwidth Management Scheme for Heterogeneous Virtualized Networks2018In: 2018 IEEE 23RD INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA), IEEE , 2018, p. 1079-1082Conference paper (Refereed)
    Abstract [en]

    With envisioned increased density and complexity of future industrial networks, software defined networking (SDN) and network virtualization are considered to be promising techniques for network organization and management. Thus, in this paper we look at heterogeneous software defined networks consisting of several virtual slices and present a bandwidth control algorithm, which is designed to provide control over shared bandwidth both in wired and wireless parts of the network. The designed algorithm has been implemented in real hardware and in this paper we present the initial test results.

  • 36.
    Inam, Rafia
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Mäki-Turja, Jukka
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering.
    Afshar, Sara
    Mälardalen University, School of Innovation, Design and Engineering.
    Hierarchical Scheduling Framework Implementation in FreeRTOS2011Report (Other academic)
    Abstract [en]

    This report presents the implementation of hierarchical scheduling framework HSF on an open source real-time operating system FreeRTOS to support the temporal isolation of a number of real-time components (or applications) onto a single processor. The goal is to achieve predictable integration and reusability of independently developed components or tasks. It presents the initial results of the HSF implementation by running it on an AVR 32-bit board EVK1100. It addresses the fixed-priority preemptive scheduling at both global and local scheduling levels. It describes the detailed design of HSF with the emphasis of doing minimal changes to the underlying FreeRTOS kernel and keeping its API intact. Finally it provides (and compares) the results for the performance measures of periodic and deferrable servers with respect to the overhead of the implementation. Index Terms: real-time systems; hierarchical scheduling framework; fixed-priority scheduling

  • 37.
    Inam, Rafia
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Mäki-Turja, Jukka
    Mälardalen University, School of Innovation, Design and Engineering.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering.
    Afshar, Sara
    Mälardalen University, School of Innovation, Design and Engineering.
    Support for Hierarchical Scheduling in FreeRTOS2011In: 2011 IEEE 16TH CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION (ETFA) / [ed] IEEE Industrial Electronic Society, IEEE conference proceedings, 2011, p. 1-10Conference paper (Refereed)
    Abstract [en]

    This paper presents the implementation of a HierarchicalScheduling Framework (HSF) on an open sourcereal-time operating system (FreeRTOS) to support the temporalisolation between a number of applications, on a single processor.The goal is to achieve predictable integration and reusability ofindependently developed components or applications. We presentthe initial results of the HSF implementation by running it onan AVR 32-bit board EVK1100.

    The paper addresses the fixed-priority preemptive schedulingat both global and local scheduling levels. It describes the detaileddesign of HSF with the emphasis of doing minimal changes tothe underlying FreeRTOS kernel and keeping its API intact.Finally it provides (and compares) the results for the performancemeasures of idling and deferrable servers with respect to theoverhead of the implementation.

  • 38.
    Iqbal, Zahid
    et al.
    University of Porto, Portugal.
    Almeida, Luis
    University of Porto, Portugal.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Analyzing the Efficiency of Sporadic Reservations on Ethernet with FTT-SE2017In: International Conference on Emerging Technologies And Factory Automation ETFA'17, 2017Conference paper (Refereed)
    Abstract [en]

    Ethernet is a promising candidate for networking real-time embedded systems such as automobiles, and it is already used in several embedded scopes, such as airplanes and trains. Moreover, its higher bandwidth enables applications made of dispersed embedded systems that exchange large amounts of data through the so-called Internet-of-Things, such as wide-area video sensing. In this realm, network reservations are an important design element that favor composability in the time domain thereby supporting the design of complex systems. However, reservations may impact negatively on the network bandwidth efficiency due to over-specification, particularly when they are designed to meet worst-case delay constraints. In this work, we use a specific Ethernet protocol that provides real-time reservations, namely FTT-SE, and we assess through extensive simulations the efficiency of a worst-case network delay analysis for sporadic reservations associated to asynchronous messages. Essentially, we compare the analytical worst-case delay with the one observed in the simulations using two data sets comprising up to 20000 and 100000 message sets, respectively, and we change the system configuration, namely properties of the message sets and network and protocol configuration parameters. We find that the analysis is accurate, i.e. matches observations, for a significant percentage of messages in the message sets (up to 60% on average). Conversely, we found that a small percentage of message sets (below 6%) generated rather pessimistic analytic estimates exceeding the observations by 6 times, thus with a negative impact on efficiency. The results we present in the paper, particularly their distributions, inform system designers of how to tune their designs to improve network bandwidth efficiency under strict timing constraints.

  • 39.
    Khalilzad, Nima
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IT/DEEC/University of Porto, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Adaptive Multi-Resource End-to-End Reservations for Component-Based Distributed Real-Time Systems2015In: ESTIMedia 2015 - 13th IEEE Symposium on Embedded Systems for Real-Time Multimedia, 2015, p. Article number 7351772-Conference paper (Refereed)
    Abstract [en]

    Complexity in the real-time embedded softwaredomain has been growing rapidly. The component-based softwaredevelopment approach facilitates the development process of suchsoftware systems by dividing a complex system into a numberof simpler components. Resource reservation techniques havebeen widely used for providing resources to real-time softwarecomponents. In this paper we target real-time components operatingon a distributed resource infrastructure. Furthermore,we target a class of software components which demonstratedynamic resource consumption behavior. A prime example ofsuch components is a multimedia software component. In thepaper, we present a framework supporting multi-resource endto-end resource reservations. We reserve resource bandwidths onboth processor resources as well as on the network resources. Theproposed framework utilizes a Multiple Input Multiple Output(MIMO) controller which adjusts the sizes of reservations trackingthe dynamic resource demands of the software components. Finally, we present a case study using a multimedia component todemonstrate the performance and efficiency of our framework.

  • 40.
    Khalilzad, Nima
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Almeida, Luis
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. University of Porto, Portugal.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Towards Adaptive Resource Reservations for Component-Based Distributed Real-Time Systems2015In: ACM SIGBED Review - Special Issue on the 7th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2015), 2015, p. 24-27Conference paper (Refereed)
    Abstract [en]

    —In this paper we present our ongoing work on developing a framework supporting adaptive resource reservations targeting component-based distributed real-time systems. The components may be spread over different resources in a distributed system. The proposed framework utilizes a reservationbased scheduling technique in which the sizes of reservations are adjusted during run-time to deal with dynamic resource demands of the software components. We present our modeling approach, we describe design options made and we present corresponding challenges.

  • 41.
    Leonardi, Luca
    et al.
    University of Catania, Italy.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fotouhi, Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lo Bello, Lucia
    University of Catania, Italy.
    A Proposal Towards Software-Defined Management of Heterogeneous Virtualized Industrial Networks2019In: IEEE International Conference on Industrial Informatics INDIN'19, 2019Conference paper (Refereed)
  • 42.
    Moghaddami Khalilzad, Nima
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sander, Ingo
    Royal Institute of Technology (KTH), Sweden.
    Towards Designing Efficient End-to-end Resource Reservations for Distributed Embedded Systems2016In: Forum on specification & Design Languages FDL'16, Bremen, Germany, 2016Conference paper (Refereed)
  • 43.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Abbaspour Asadollah, Sara
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pei-Breivold, Hongyu
    ABB Corporate Research, Sweden.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IS (Embedded Systems).
    Management of Service Level Agreements for Cloud Services in IoT: A Systematic Mapping Study2017In: IEEE Access, E-ISSN 2169-3536, no 99Article in journal (Refereed)
    Abstract [en]

    Cloud computing and Internet of Things (IoT) are computing technologies that provide services to consumers and businesses, allowing organizations to become more agile and flexible. Therefore, ensuring Quality of Service (QoS) through Service Level Agreements (SLAs) for such cloud-based services is crucial for both the service providers and service consumers. As SLAs are critical for cloud deployments and wider adoption of cloud services, the management of SLAs in cloud and IoT has thus become an important and essential aspect. This paper investigates the existing research on the management of SLAs in IoT applications that are based on cloud services. For this purpose, a Systematic Mapping study (a well-defined method) is conducted to identify the published research results that are relevant to SLAs. The paper identifies 328 primary studies and categorizes them into seven main technical classifications: SLA management, SLA definition, SLA modeling, SLA negotiation, SLA monitoring, SLA violation and trustworthiness, and SLA evolution. The paper also summarizes the research types, research contributions, and demographic information in these studies. The evaluation of the results show that most of the approaches for managing SLAs are applied in academic or controlled experiments with limited industrial settings rather than in real industrial environments. Many studies focus on proposal models and methods to manage SLAs, and there is a lack of focus on the evolution perspective and a lack of adequate tool support to facilitate practitioners in their SLA management activities. Moreover, the scarce number of studies focusing on concrete metrics for qualitative or quantitative assessment of QoS in SLAs urges the need for in-depth research on metrics definition and measurements for SLAs.

  • 44.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Integrating Response-Time Analyses for Heterogeneous Automotive Networks in MPS-CAN Analyzer2015In: 6th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems WATERS 2015, 2015Conference paper (Refereed)
    Abstract [en]

    MPS-CAN analyzer is a research tool that supports the Response Time Analysis (RTA) for Controller Area Network (CAN). It takes into account various queueing policies; buffer limitations in the CAN controllers; and mixed transmission patterns supported by the higher-level protocols. In this paper, we extend the MPS-CAN analyzer to support RTA of heterogeneous automotive networks. Within this context, first we implement RTA for Ethernet Audio/Video Bridging (AVB) messages in a single-switch architecture. We then integrate the analyses for CAN and Ethernet AVB by exploiting the analysis for CAN to Ethernet AVB gateway. With this integration, the MPS-CAN analyzer supports the analysis for heterogeneous messages that traverse through heterogeneous networks consisting of CAN and Ethernet AVB. We also evaluate the newly implemented analyses by conducting an automotive-application case study.

  • 45.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lundbäck, J.
    Arcticus Systems AB, Järfälla, Sweden .
    Lundbäck, K-L
    Arcticus Systems AB, Järfälla, Sweden .
    Integrating Response-time Analysis for Heterogeneous Networks with Rubus Analysis Framework: Challenges and Preliminary Solutions2015In: 2015 IEEE 20th Conference on Emerging Technologies & Factory Automation (ETFA 2015): Proceedings of a meeting held 8-11 September 2015, Luxembourg., 2015Conference paper (Refereed)
    Abstract [en]

    In this paper we discuss the challenges that are faced when the state-of-the-art research results are transferred to a model-based tool chain for the industrial use. These challenges are often overlooked when the research results are implemented in an academic environment. In particular, we discuss various challenges regarding the implementation and integration of the response-time analysis for heterogeneous networks, comprising of CAN and Ethernet AVB, as a plug-in for the Rubus Analysis Framework. Rubus tool suite is used for the model- and component-based development of software for vehicular real-time systems by several international companies. We also discuss preliminary solutions to deal with the challenges.

  • 46.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Mohammad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolte, Thomas
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Lundbäck, John
    Arcticus Systems AB, Järfälla, Sweden.
    Gålnander, Mattias
    Arcticus Systems AB, Järfälla, Sweden.
    Lundbäck, Kurt-Lennart
    Arcticus Systems AB, Järfälla, Sweden.
    Modeling of End-to-end Resource Reservations in Component-based Vehicular Embedded Systems2016In: Software Engineering and Advanced Applications (SEAA), 2016 42th Euromicro Conference on, 2016, p. 283-292Conference paper (Refereed)
    Abstract [en]

    There is a plethora of models, techniques and toolsthat support model- and component-based software developmentof vehicular distributed embedded systems. However, a large ma-jority of them have a limited or no support to model and specifyend-to-end resource reservations on the software architecturesof these systems. Resource reservations allow flexibility duringthe development and execution of such complex systems withoutjeopardizing their predictable behavior. As a result, severalapplications in the system that share the same hardware platformcan be developed independently. In this paper we identify severalrequirements that any existing component model should fulfill inorder to support the modeling of end-to-end resource reservationson the software architectures of such systems. As a proof ofconcept, we extend the Rubus Component Model (RCM) byfulfilling these requirements. RCM is used for the development ofcontrol functionality in vehicular embedded systems by severalinternational companies. We also provide a technique to extractexecution models from the software architectures of these systemswith resource reservations. In order to show the usability of ourtechnique, we model a vehicular distributed embedded systemwith the extended component model and extract the executionmodel from the software architecture augmented with end-to-endresource reservations.

  • 47.
    Mubeen, Saad
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Nolin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Holistic Modeling of Time Sensitive Networking in Component-based Vehicular Embedded SystemsIn: Euromicro Conference on Software Engineering and Advanced Applications SEAA 2019, Kallithea, Chalkidiki, GreeceConference paper (Refereed)
    Abstract [en]

    This paper presents the first holistic modeling approach for Time-Sensitive Networking (TSN) communication that integrates into a model- and component-based software development framework for distributed embedded systems. Based on these new models, we also present an end-to-end timing model for TSN-interconnected distributed embedded systems. Our approach is expressive enough to model the timing information of TSN and the timing behaviour of software that communicates over TSN, hence allowing end-to-end timing analysis. A proof of concept for the proposed approach is provided by implementing it for a component model and tool suite used in the vehicle industry. Moreover, a use case from the vehicle industry is modeled and analyzed with the proposed approach to demonstrate its usability.

  • 48.
    Papadopoulos, Alessandro
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Abbaspour Asadollah, Sara
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Arcticus Systems AB, Järfälla, Sweden.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Arcticus Systems AB, Järfälla, Sweden.
    Pei Breivold, Hongyu
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. ABB Corporate Research, Sweden.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    SLAs for Industrial IoT: Mind the Gap2017In: The 4th International Symposium on Inter-cloud and IoT (ICI 2017) ICI'17, 2017, p. 75-78Conference paper (Refereed)
    Abstract [en]

    Cloud computing and Internet of Things (IoT) are computing technologies that provide services to consumers and businesses, allowing organizations to become more agile and flexible. The potential business values that cloud consumers can achieve depend a lot on the quality of service in the provided cloud services. Therefore, ensuring the quality of service through service-level agreements (SLA) for such cloud-based services is crucial for both the service providers and service consumers. As SLA is critical for cloud deployments and wider adoption of cloud services, the management of SLA in cloud and IoT has thus become an important and essential issue. In this paper we provide an understanding of the current status and maturity level of SLA management in industrial IoT and academic efforts in this field. We also conduct a preliminary survey of current research on SLA management in order to identify open challenges and gaps that need to be addressed in future research directions. In particular, we investigate how to provide useful SLA management support adapted to the maturity level and current industrial practices, and shorten the gap between academia and industry.

  • 49.
    Struhar, Vaclav
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Craciunas, Silviu
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    DART: Dynamic Bandwidth Distribution Framework for Virtualized Software Defined Networks2019In: IEEE 45th Annual Conference of the Industrial Electronics Society IECON'19, 2019Conference paper (Refereed)
  • 50.
    Zahid, I.
    et al.
    University of Porto, Porto, Portugal.
    Almeida, L.
    University of Porto, Porto, Portugal.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Behnam, Moris
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    On the efficiency of sporadic servers on ethernet with FTT-SE2017In: SIGBED Review, ISSN 1551-3688, Vol. 14, no 3, p. 32-34Article in journal (Refereed)
1 - 50 of 50
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