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The paper presents recent technological advancements that have been made by Siemens PLM in its simulation tools for multi-body analyses and multi-physics simulation in order to run physics-based high fidelity models in real-time. The motivation is enable reuse of simulation models developed during the engineering phase during the validation phase with hardware or humans in the loop. To demonstrate...
This paper proposes an approach to modelling and analysis of distributed real-time actor systems, which is based on the Uppaal statistical model checker (SMC). SMC was chosen because it automatizes simulations, offers a temporal logic language to formalize specifications and exploits statistical techniques to infer quantitative measures about a model. The approach is integrated in a system life-cycle...
1To tackle the unavoidable self-suspension behavior due to I/O-intensive interactions, multi-core processors, computation offloading systems with coprocessors, etc., the dynamic and the segmented self-suspension sporadic task models have been widely used in the literature. We propose new self-suspension models that are hybrids of the dynamic and the segmented models. Those hybrid models are capable...
Distributed real-time simulation allows the sharing of simulator equipment and components connected in Hardware-In-the-Loop experiments. In this paper, we analyze the challenges of geographically distributed real-time power system simulation and how dynamic phasors could be applied to improve the accuracy of the simulation results for large time steps. The time step is of particular interest since...
In this paper, we deal with the problem of determining when and where a bus should short-turn on a single bi-directional line in real-time. We formulate a decision rule for when to short-turn among candidate short-turning locations that is based on the objective of minimizing total generalized passenger travel cost including waiting times and forced transfer. Computational results and analysis are...
Real-time Calculus (RTC) is a non-stochastic queuing theory to the worst-case performance analysis of distributed real-time systems. Workload as well as resources are modelled as piece-wise linear, pseudo-periodic curves and the system under investigation is modelled as a sequence of algebraic operations over these curves. The memory footprint of computed curves increases exponentially with the sequence...
The purpose of a real-time simulation is to provide a closed loop system required for validating the control firmware or application. Detailed plant model with tolerable accuracy and achieving required real-time model execution time are conflicting requirements for a given embedded target hardware. In design of control methods for Pulse Width Modulation (PWM) inverters analytical models are important...
DAG-based scheduling models have been shown to effectively express the parallel execution of current many-core heterogeneous architectures. However, their applicability to real-time settings is limited by the difficulties to find tight estimations of the worst-case timing parameters of tasks that may arbitrarily be preempted/migrated at any instruction. An efficient approach to increase the system...
We present an approach to model the deployment costs, including compute and IO costs, of Microservice-based applications deployed to a public cloud. Our model, which we dubbed CostHat, supports both, Microservices deployed on traditional IaaS or PaaS clouds, and services that make use of novel cloud programming paradigms, such as AWS Lambda. CostHat is based on a network model, and allows for what-if...
Real-time systems with functional dependencies between tasks often require end-to-end (as opposed to task-level) guarantees. For many of these systems, it is even possible to accept the possibility of longer end-to-end delays if one can bound their frequency. Such systems are called weakly-hard. In this paper we provide end-to-end deadline miss models for systems with task chains using Typical Worst-Case...
REDEFINE is a distributed dynamic dataow architecture, designed for exploiting parallelism at various granularities as an embedded system-on-chip (SoC). is paper dwells on the exibility of REDEFINE architecture and its execution model in accelerating real-time applications coupled with a WCET analyzer that computes execution time bounds of real time applications.
The amount of security critical information that is only available in digital form is increasing constantly. Some of these data, such as medical or tax data, need to be preserved for long periods of time. Thus, several schemes for long-term integrity protection of long-lived and archived data were developed. However, a comprehensive security analysis is still missing. In this paper we discuss existing...
Modeling and Simulation methods have been used to better analyze the behavior of complex physical systems and it is now common to use simulation as a part of the scientific and technological discovery process. Formal M&S proved to be successful in providing a sound base for the development of discrete-event simulation models, improving the ease of model definition and enhancing application development...
Real-time streaming applications with cyclic data dependencies that are executed on multiprocessor systems with processor sharing usually require a temporal analysis to give guarantees on their temporal behavior at design time. Current accurate analysis techniques for cyclic applications that are scheduled with Static Priority Preemptive (SPP) schedulers are however limited to the analysis of applications...
This paper proposes an extension to dataflow models with timing specifications to facilitate the construction of deterministic, platform independent, precisely timed models of software in cyber-physical systems (CPS). Dataflow models are often used to describe the software/cyber part of a CPS, owing to their succinct and analyzable representation of computation and concurrency. To capture the interaction...
The development of Internet and Web systems in recent years has made it difficult and challenging to deal with large-scale data. What we usually need to process is incremental data, the scale of which will enlarge with the changing of time. Nowadays, many general queries over data is traditionally based on the full amount of raw data, which becomes a great challenge to performance when the data increases...
Providing guarantees on the system behavior is mandatory in order to let the robots enter our every-day life. Among these guarantees, proving the fulfillment of real-time constraints on the software is a key issue, as their violation could result into unexpected and unsafe behaviors. In this paper, we present a methodology to guarantee real-time constraints on component-based software architectures...
The automatic generation of witness and counterexample is considered as the key advantage of model checking. It provides a useful source of diagnostic information and a basis for automated test generation. However, some of the witness traces may be unreasonably long and highly redundant that makes achieving test purpose even for small systems inefficient. This paper presents a technique for automated...
With the rapid development of big data analytics in online marketing, real-time bidding (RTB) has emerged as a promising business model in recent years and now becomes one of the major online advertising channels. Based on analysis of Web Cookies, RTB platforms are able to precisely identify the features and preferences of target audiences visiting publishers' websites, and forward the information...
Network calculus (also known as real-time calculus) and event stream theory are two theories designed to compute upper bounds on response time for real-time systems. Both generalise the common periodic request arrival to any kind of workload using cumulative functions. In network calculus, a data flow is modelled by its cumulative curve, A(t), representing the amount of data sent by the flow up to...
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