| 1. |
- Ghaderi, Adnan, et al.
(författare)
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Design challenges in hardware development of time-sensitive networking : A research plan
- 2019
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Ingår i: CEUR Workshop Proceedings, Volume 2457. - : CEUR-WS.
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Afshar, Sara Zargari, et al.
(författare)
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Investigating Alternatives for System Architectures to Enhance Discrete Manufacturing
- 2019
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Ingår i: International Journal of Distributed Sensor Networks. - Sweden : SAGE Publications. - 1550-1329 .- 1550-1477. ; 15:8
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Aglianò, Simone, et al.
(författare)
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Resource Management and Control in Virtualized SDN Networks
- 2018
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Ingår i: CSI International Symposium on Real-Time and Embedded Systems and Technologies REST'18. - 9781538614754 ; , s. 47-53
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 4. |
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| 5. |
- Ashjaei, Mohammad, et al.
(författare)
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Dynamic reconfiguration in HaRTES switched ethernet networks
- 2016
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Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS. - 9781509023394
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 6. |
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| 7. |
- Ashjaei, Mohammad, et al.
(författare)
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End-to-end Resource Reservations in Distributed Embedded Systems
- 2016
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Ingår i: Proceedings - 2016 IEEE 22nd International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2016. ; , s. 1-11
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 8. |
- Ashjaei, Mohammad, et al.
(författare)
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Improved Message Forwarding for Multi-Hop HaRTES Real-Time Ethernet Networks
- 2016
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Ingår i: Journal of Signal Processing Systems. - : Springer Science and Business Media LLC. - 1939-8018 .- 1939-8115. ; 84:1, s. 47-67
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Tidskriftsartikel (refereegranskat)abstract
- 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 %.
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| 9. |
- Ashjaei, Mohammad, et al.
(författare)
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MTU Configuration for Real-Time Switched Ethernet Networks
- 2016
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Ingår i: Journal of systems architecture. - : Elsevier BV. - 1383-7621 .- 1873-6165. ; 70, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 10. |
- Ashjaei, Mohammad, 1980-
(författare)
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Real-Time Communication over Switched Ethernet with Resource Reservation
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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