| 1. |
- Aisa, Jesus, et al.
(författare)
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DoTHa - A Double-threshold Hand-off Algorithm for Managing Mobility in Wireless Mesh Networks
- 2016
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Ingår i: 21st IEEE Conference on Emerging Technologies and Factory Automation ETFA'16. - 9781509013142
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Konferensbidrag (refereegranskat)abstract
- Wireless communication will play an increasingly important role in future factory automation and process control, where the presence of mobile autonomous devices is expected to grow. However, wireless links are prone to errors due to shadowing and multi-path fading, which is even more severe in dynamic environments. These problems can be attenuated by using a mesh backbone to which mobile node connect to, using a hand-off algorithm. This solution is particularly important under real-time requirements typically found in factory automation. In this paper, we devise the Double-Threshold Hand-off (DoTHa) algorithm, a novel hand-off mechanism that triggers a hand-off in various environmental conditions. As a case study, we carry out the tele-operation of a mobile robot through a wireless mesh network in an indoor setting, using a wireless chain network protocol (WICKPro-SRT) that supports soft real-time traffic. We empirically compared DoTHa with two existing hand-off algorithms based on single and double hysteresis margin. The results revealed that DoTHa achieves Data Delivery Ratio (DDR) close to 100% whereas the single hysteresis-based hand-off suffers from frequent disconnections, dropping DDR to 88%. The double hysteresis-based hand-off shows higher ping-pong effect than DoTHa, doubling the number of hand-offs in some scenarios.
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| 2. |
- Blech, Jan Olaf, et al.
(författare)
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A Comparison of Formal Verification Approaches for IEC 61499
- 2016
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Ingår i: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA). - Piscataway, NJ : IEEE conference proceedings. - 9781509013142 - 9781509013135
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Konferensbidrag (refereegranskat)abstract
- Engineering and computer science have come up with a variety of techniques to increase the confidence in systems, increase reliability, facilitate certification, improve reuse and maintainability, improve interoperability and portability. Among them are various techniques based on formal models to enhance testing, validation and verification. In this paper, we are concentrating on formal verification both at runtime and design time of a system. Formal verification of a system property at design time is the process of mathematically proving that the property indeed holds. At runtime, one can check the validity of the property and report deviations by monitoring the system execution. Formal verification relies on semantic models, descriptions of the system and its properties. We report on ongoing verification work and present two different approaches for formal verification of IEC 61499-based programs. We provide two examples of ongoing work to exemplify the design and the runtime verification approaches
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| 3. |
- Chen, DeJiu, et al.
(författare)
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A Model-Based Approach to Qualified Process Automation for Anomaly Detection and Treatment
- 2016
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Ingår i: 21st IEEE International Conference on Emerging Technology & Factory Automation, ETFA 2016. - : IEEE conference proceedings. - 9781509013142
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Konferensbidrag (refereegranskat)abstract
- Modern machineries are becoming complex cyberphysicalsystems with increasingly intelligent support for processautomation. For the dependability and performance, acombination of measures for fault avoidance, robust architecture,and runtime anomaly handling is necessary. These in turn callfor a formalization of knowledge across different system lifecyclestages and a provision of novel methods and tools for qualifiedsystem synthesis and effective risk management. This paperpresents a model-based approach to qualified process automationfor the operation and maintenance of production systems. Thecontribution is centered on the formalizations of a wide range ofsystem concerns, and thereby a consolidation of the rationalebehind the design of run-time process logic in BPMN2.0. Inparticular, the approach allows an integration of formal systemdescriptions, FTA and FEMA based anomaly analysis, andexecutable process models for effective anomaly detection andtreatment. The approach adopts mature modeling methods andtools through EAST-ADL. In this paper, a prototype tool-chainwith MetaEdit+ Domain-Specific Modeling (DSM) Workbench,HiP-HOPS Analysis Tool and Camunda BPM Platform is alsopresented.
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| 4. |
- Faragardi, Hamid Reza, et al.
(författare)
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EAICA : An energy-aware resource provisioning algorithm for Real-Time Cloud services
- 2016
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 9781509013142
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Konferensbidrag (refereegranskat)abstract
- Cloud computing is receiving an increasing attention when it comes to providing a wide range of cost-effective services. In this context, energy consumption of communication and computing resources contribute to a major portion of the cost of services. On the other hand, growing energy consumption not only results in a higher operational cost, but it also causes negative environmental impacts. A large number of cloud applications in, e.g., telecommunication, multimedia, and video gaming, have real-time requirements. A cloud computing system hosting such applications, that requires a strict timing guarantee for its provided services, is denoted a Real-Time Cloud (RTC). Minimizing energy consumption in a RTC is a complicated task as common methods that are used for decreasing energy consumption can potentially lead to timing violations. In this paper, we present an online energy-aware resource provisioning framework to reduce the deadline miss ratio for real-time cloud services. The proposed provisioning framework not only considers the energy consumption of servers but it also takes the energy consumption of the communication network into account, to provide a holistic solution. An extensive range of simulation results, based on real data, show a noticeable improvement regarding energy consumption while keeping the number of timing violations less than 1% in average.
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| 5. |
- Farooqui, Ashfaq Hussain, 1990, et al.
(författare)
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Error handling within highly automated automotive industry: Current practice and research needs
- 2016
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 1946-0759 .- 1946-0740. - 9781509013142 ; 2016-November, s. Art no 7733628-
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Konferensbidrag (refereegranskat)abstract
- Fault tolerant systems, commonly found in literature, are implemented in various computer applications. Some of these methods have been studied and developed to aid manufacturing systems; however, they have rarely been integrated into the manufacturing process. Broadly, the problem seems to be integration of error handling procedures towards the end of physically building the manufacturing line, lack of a defined workflow, untested program logic and inadequately equipped personnel to name a few. To this end, a survey was conducted within the Swedish automotive industry to get an understanding of current error handling procedures and its shortcomings, and are presented here. Based on this data, and looking at the trends within the manufacturing industry, this paper also identifies research topics aimed towards defining methods to create next generation fault tolerant manufacturing systems.
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| 6. |
- Ferreira, Luis Lino, et al.
(författare)
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QoS-as-a-Service in the local cloud
- 2016
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Ingår i: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA). - Piscataway, NJ : IEEE conference proceedings. - 9781509013142 - 9781509013135
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Konferensbidrag (refereegranskat)abstract
- This paper presents an architecture that supports Quality of Service (QoS) in an Arrowhead-compliant System of Systems (SoS). The Arrowhead Framework supports local cloud functionalities for automation applications, provided by means of a Service Oriented Architecture (SOA), by offering a number of services that ease application development. On such applications the QoS guarantees are required for service fruition, and are themselves requested as services from the framework. To fulfil this objective we start by describing the Arrowhead architecture and the components needed to dynamically in run-time negotiate a system configuration that guarantees the QoS requirements between application services
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| 7. |
- Leon, Miguel, et al.
(författare)
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Designing optimal harmonic filters in power systems using greedy adaptive Differential Evolution
- 2016
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 9781509013142
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Konferensbidrag (refereegranskat)abstract
- Harmonic filtering has been widely applied to reduce harmonic distortion in power distribution systems. This paper investigates a new method of exploiting Differential Evolution (DE) to support the optimal design of harmonic filters. DE is a class of stochastic and population-based optimization algorithms that are expected to have stronger global ability than trajectory-based optimization techniques in locating the best component sizes for filters. However, the performance of DE is largely affected by its two control parameters: scaling factor and crossover rate, which are problem dependent. How to decide appropriate setting for these two parameters presents a practical difficulty in real applications. Greedy Adaptive Differential Evolution (GADE) algorithm is suggested in the paper as a more convenient and effective means to automatically optimize filter designs. GADE is attractive in that it does not require proper setting of the scaling factor and crossover rate prior to the running of the program. Instead it enables dynamic adjustment of the DE parameters during the course of search for performance improvement. The results of tests on several problem examples have demonstrated that the use of GADE leads to the discovery of better filter circuits facilitating less harmonic distortion than the basic DE method.
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| 8. |
- Lindgren, Per, et al.
(författare)
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Towards Certified Compilation of RTFM-core Applications
- 2016
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Ingår i: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA). - Piscataway, NJ : IEEE conference proceedings. - 9781509013142 - 9781509013135
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Konferensbidrag (refereegranskat)abstract
- Concurrent programming is dominated by threadbased solutions with lock based critical sections. Careful attentionhas to be paid to avoid race and deadlock conditions. Real-Timefor The Masses (RTFM) takes an alternative language approach,introducing tasks and named critical sections (via resources)natively in the RTFM-core language. RTFM-core programs canbe compiled to native C-code, and efficiently executed ontosingle-core platforms under the Stack Resource Policy (SRP)by the RTFM-kernel. In this paper we formally define thewell-formedness criteria for SRP based resource management,and develop a certified (formally proven) implementation ofthe corresponding compilation from nested critical sections ofthe input RTFM-core program to a resulting flat sequence ofprimitive operations and scheduling primitives. Moreover weformalise the properties for resource ceilings under SRP anddevelop a certified algorithm for their computation.The feasibility of the described approach is shown throughthe adoption of the Why3 platform, which allows the necessaryverification conditions to be automatically generated and dischargedthrough a variety of automatic external SMT-solversand interactive theorem provers. Moreover, Why3 supports theextraction of certified Ocaml code for proven implementationsin WhyML. As a proof of concept the certified extracteddevelopment is demonstrated on an example system.
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| 9. |
- Lindner, Marcus, et al.
(författare)
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Safe tasks : run time verification of the RTFM-lang model of computation
- 2016
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Ingår i: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA). - Piscataway, NJ : IEEE conference proceedings. - 9781509013142 - 9781509013135
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Konferensbidrag (refereegranskat)abstract
- Embedded systems for critical applications are typicallyspecified with requirements on predictable timing andsafety. While ensuring predictable timing, the RTFM-lang (Real-Time For the Masses) model of computation (MoC) currentlylacks memory access protection among real-time tasks. In thispaper, we discuss how to safely verify task execution given aspecification using the RTFM-MoC. Furthermore, an extensionto the RTFM-core infrastructure is outlined and tested with usecases of embedded development. We propose a method for runtime verification exploiting memory protection hardware. Forthis purpose, we introduce memory resources to the declarativelanguage RTFM-core allowing compliance checks. As a proofof concept, compiler support for model analysis and automaticgeneration of run time verification code is implemented togetherwith an isolation layer for the RTFM-kernel. With this verificationfoundation, functional run time checks as well as furtheroverhead assessments are future research questions.
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| 10. |
- Mercader, Pedro, et al.
(författare)
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Autotuning of an In-Line pH Control System
- 2016
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Ingår i: 2016 IEEE 21st Conference on Emerging Technologies and Factory Automation (ETFA 2016). - 9781509013142
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Konferensbidrag (refereegranskat)abstract
- A novel autotuning procedure is presented through application to an industrial in-line pH control system. The procedure has three advantages over classical relay auto-tuners: experiment duration is very short (no need for limit-cycle convergence); all data is used for identification (instead of only peaks and switch instances); a parameter uncertainty model is identified and utilized for robust controller synthesis.
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