Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

物件導向軟體之架構(Object-Oriented Software Construction)探討

ing WS1S Systems to Verify Parameterized Networks . . . . . . . . . . . . 188 Kai Baukus, Saddek Bensalem, Yassine Lakhnech and Karsten Stahl FMona: A Tool for Expressing Validation Techniques over Infinite State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 J.-P. Bodeveix and M. Filali Transitive Closures of Regular Relations for Verifying Infinite-State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Bengt Jonsson and Marcus Nilsson Diagnostic and Test Generation Using Static Analysis to Improve Automatic Test Generation . . . . . . . . . . . . . 235 Marius Bozga, Jean-Claude Fernandez and Lucian Ghirvu Efficient Diagnostic Generation for Boolean Equation Systems . . . . . . . . . . . . 251 Radu Mateescu Efficient Model-Checking Compositional State Space Generation with Partial Order Reductions for Asynchronous Communicating Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Jean-Pierre Krimm and Laurent Mounier Checking for CFFD-Preorder with Tester Processes . . . . . . . . . . . . . . . . . . . . . . . 283 Juhana Helovuo and Antti Valmari Fair Bisimulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Thomas A. Henzinger and Sriram K. Rajamani Integrating Low Level Symmetries into Reachability Analysis . . . . . . . . . . . . . 315 Karsten Schmidt Model-Checking Tools Model Checking Support for the ASM High-Level Language . . . . . . . . . . . . . . 331 Giuseppe Del Castillo and Kirsten Winter Table of

Tools and Algorithms for the Construction and Analysis of Systems. Proc. TACAS 2009

All one needs to know about fog computing and related edge computing paradigms: A complete survey

Digital twin can be defined as a virtual representation of a physical asset enabled through data and simulators for real-time prediction, optimization, monitoring, controlling, and improved decision making. Recent advances in computational pipelines, multiphysics solvers, artificial intelligence, big data cybernetics, data processing and management tools bring the promise of digital twins and their impact on society closer to reality. Digital twinning is now an important and emerging trend in many applications. Also referred to as a computational megamodel, device shadow, mirrored system, avatar or a synchronized virtual prototype, there can be no doubt that a digital twin plays a transformative role not only in how we design and operate cyber-physical intelligent systems, but also in how we advance the modularity of multi-disciplinary systems to tackle fundamental barriers not addressed by the current, evolutionary modeling practices. In this work, we review the recent status of methodologies and techniques related to the construction of digital twins mostly from a modeling perspective. Our aim is to provide a detailed coverage of the current challenges and enabling technologies along with recommendations and reflections for various stakeholders.

/pdf/digital-twin-values-challenges-and-enablers-from-a-modeling-3hpoelaogn.pdf

Digital Twin: Values, Challenges and Enablers From a Modeling Perspective

The enhancements being developed by the Time-Sensitive Networking Task Group as part of IEEE 802.1 emerge as the future of real-time communication over Ethernet networks for automotive and industrial application domains. In particular IEEE 802.1Qbv is key to enabling timeliness guarantees via so-called time-aware shapers. In this paper, we address the computation of fully deterministic schedules for 802.1Qbv-compliant multi-hop switched networks. We identify and analyze key functional parameters affecting the deterministic behaviour of real-time communication under 802.1Qbv and, based on a generalized configuration of these parameters, derive the required constraints for computing offline schedules guaranteeing low and bounded jitter and deterministic end-to-end latency for critical communication flows. Furthermore, we discuss several optimization directions and concrete configurations exposing trade-offs against the required computation time. We also show the performance of our approach via synthetic network workloads on top of different network configurations.

Scheduling Real-Time Communication in IEEE 802.1Qbv Time Sensitive Networks

Networks for real-time systems have stringent end-to-end latency and jitter requirements. One cost-efficient way to meet these requirements is the time-triggered communication paradigm which plans the transmission points in time of the frames off-line. This plan prevents contentions of frames on the network and is called a time-triggered schedule (tt-schedule). In general the tt-scheduling is a bin-packing problem, known to be NP-complete, where the complexity is mostly driven by the freedom in topology of the network, its associated hardware restrictions, and application-imposed constraints. Multi-hop networks, in particular, require the synthesis of path-dependent tt-schedules to maintain full determinism of time-triggered communication from sender to receiver. Our experiments using the YICES SMT solver show that the scheduling problem can be solved by YICES out-of-the-box for a few hundred random frame instances on the network. A customized tt-scheduler using YICES as a back-end solver allows to increase this number of frame instances up to tens of thousands. In terms of scheduling quality, the synthesis produces up to ninety percent maximum utilization on a communication link with schedule synthesis times of about half an hour for the biggest examples we have studied. As a nice side-effect the YICES out-of-the-box approach is immediately applicable for the verification of existing (even large-scale) tt-schedules and for debugging more sophisticated tt-schedulers.

An Evaluation of SMT-Based Schedule Synthesis for Time-Triggered Multi-hop Networks

Networks are a core element of many industrial and automation systems at present. Often these networks transport time- and safety-critical messages that control physical processes. Thus, timely and guaranteed delivery is an essential property of networks for such critical systems. Over the past decade, a variety of network solutions have evolved to satisfy said properties. However, these solutions are largely incompatible with each other and many system architects are forced to deploy different solutions in parallel due to their different capabilities. IEEE 802.1 Time-Sensitive Networking (TSN) is a standardization group that enhances IEEE networking standards, most prominently Ethernet-based networks, with said properties and has the unique potential to evolve as a cross-industry mainstream networking technology. In this survey paper, we give an overview of TSN in industrial communication and automation systems and discuss specific TSN standards and projects in detail as well as their applicability to various industries.

A Perspective on IEEE Time-Sensitive Networking for Industrial Communication and Automation Systems

In this study the authors are interested in safety-critical real-time applications implemented on distributed architectures supporting the time-sensitive networking (TSN) standard. The on-going standardisation of TSN is an IEEE effort to bring deterministic real-time capabilities into the IEEE 802.1 Ethernet standard supporting safety-critical systems and guaranteed quality-of-service. TSN will support time-triggered (TT) communication based on schedule tables, audio-video-bridging (AVB) flows with bounded end-to-end latency as well as best-effort messages. The authors first present a survey of research related to the optimisation of distributed cyber-physical systems using real-time Ethernet for communication. Then, the authors formulate two novel optimisation problems related to the scheduling and routing of TT and AVB traffic in TSN. Thus, the authors consider that they know the topology of the network as well as the set of TT and AVB flows. The authors are interested to determine the routing of both TT and AVB flows as well as the scheduling of the TT flows such that all frames are schedulable and the AVB worst-case end-to-end delay is minimised. The authors have proposed an integer linear programming formulation for the scheduling problem and a greedy randomised adaptive search procedure-based heuristic for the routing problem. The proposed approaches have been evaluated using several test cases.

/pdf/design-optimisation-of-cyber-physical-distributed-systems-u4m5bumlmk.pdf

Design optimisation of cyber-physical distributed systems using IEEE time-sensitive networks

Many safety-critical real-time applications are implemented using distributed architectures, composed of heterogeneous processing elements interconnected in a network. Our focus in this paper is on the TTEthernet protocol, a deterministic, synchronized and congestion-free network protocol based on the Ethernet standard and compliant with the ARINC 664 Specification Part 7. TTEthernet is highly suitable for safety-critical real-time applications since it offers separation for messages using the concept of virtual links and supports three time-criticality classes: Time-Triggered (TT), Rate-Constrained (RC) and Best-Effort. In this paper we are interested in the design optimization of TTEthernet networks used to transmit real-time application messages. Given the set of TT and RC messages, and the topology of the network, our approach optimizes the packing of messages in frames, the assignment of frames to virtual links, the routing of virtual links and the TT static schedules, such that all frames are schedulable and the worst-case end-to-end delay of the RC messages is minimized. We propose a Tabu Search-based metaheuristic for this optimization problem. The proposed algorithm has been evaluated using several benchmarks.

http://www2.compute.dtu.dk/~paupo/publications/Tamas-Selicean2015aa-Design%20Optimization%20of%20TTEther-Real-Time%20Systems%20Journal.pdf

Wilfried Steiner

Papers

Scheduling Real-Time Communication in IEEE 802.1Qbv Time Sensitive Networks

An Evaluation of SMT-Based Schedule Synthesis for Time-Triggered Multi-hop Networks

A Perspective on IEEE Time-Sensitive Networking for Industrial Communication and Automation Systems

Design optimisation of cyber-physical distributed systems using IEEE time-sensitive networks

Design optimization of TTEthernet-based distributed real-time systems