In this paper, we first identify the potential violations of control assumptions inherent in standard real-time scheduling approaches (because presence jitters) that causes, degradation performance and may even lead to instability. We then develop practical founded on theory deal with these violations. Our approach is based notion compensations wherein controller parameters are adjusted at runtime for jitters. Through time memory overhead analysis, by elaborating implementation details,...

In this paper we present algorithms for the joint scheduling of periodic and aperiodic tasks in statically scheduled distributed real-time systems. Periodic are precedence constrained, distributed, communicating over nodes Both soft hard handled. After a static schedule has been created first step, determine amount distribution unused resources leeway it. These then used to incorporate into by shifting tasks' execution, without violating their feasibility. Run-time mechanisms simple require...

In many modern embedded platforms, safety-critical functionalities that must be certified correct to very high levels of assurance co-exist with less critical software are not subject certification requirements. Recent research in real-time scheduling theory has yielded some promising techniques for meeting the dual goals (i) being able certify under conservative assumptions, and (ii) ensuring utilization platform resources pessimistic assumptions. This centered on an event-triggered/...

High-performance embedded systems require the execution of many applications on multicore platforms and are subject to stringent restrictions constraints. The ACTORS project approach provides temporal isolation through resource reservation over a platform, adapting available resources basis overall quality requirements. architecture is fully operational both ARM MPCore x86 platforms.

Many industrial applications with real-time demands are composed of mixed sets tasks a variety requirements. These can be in the form standard timing constraints, such as periods and deadlines, or complex, e.g. to express application-specific nontemporal reliability, performance, etc. Arrival patterns determine whether treated periodic, sporadic aperiodic. As many algorithms only focus on specific task types system design has those supported by particular algorithm, at expense rest. In this...

Closed-loop control systems are dynamic subject to perturbations. One of the main concerns is design controllers correct or limit deviation that transient perturbations cause in controlled system response. The smaller and shorter deviation, better achieved performance. However, such have been traditionally implemented using fixed timing constraints (periods deadlines). This precludes execute dynamically, accordingly dynamics, which may lead sub-optimal implementations: although higher...

Wireless networks are currently considered as extension of typical wired to increase flexibility and scalability. However, this design freedom is accompanied by the reduced reliability real-time capability wireless communication. To put these advantages disadvantages in required relationship, we introduce a use case analysis factory automation applications within paper. Additionally, compare performance indicators industrial communication systems enable evaluation arising hybrid...

This paper presents an engineering approach to the design of distributed real-time systems, which guarantee hard deadlines and can tolerate a specified set faults. The methodology covers stepwise refinement given requirements, expressed in form transactions, task protocol executions. It also includes timing analysis dependability evaluation still incomplete design. testability evolving system is considered be essential concern. A coherent tools for support described some detail. assumes that...

Airbus is investigating COTS multicore platforms for safety-critical avionics applications, pursuing helicopter-style autonomous and electric aircraft. These aircraft need to be ultra-lightweight future mobility in the urban city landscape. As a step towards certification, identified new methods that preserve ARINC 653 single core schedule of Helicopter Terrain Awareness Warning System (HTAWS) application while scheduling additional partitions on other cores. As some HTAWS are...

Decoding MPEG-2 video streams imposes hard real-time constraints for consumer devices such as TV sets. The freedom of encoding choices provided by the standard results in high variability inside streams, particular with respect to frame structures and their sizes. In this paper, we identify realistic timing demanded decoding. We present from a study analyze validity common assumptions software decoding number misconceptions. Furthermore, imposed buffer handling discussed implications on...

Scheduling theory generally assumes that real-time systems are mostly composed of activities with hard requirements. Many built today by composing different applications or components in the same system, leading to a mixture many kinds requirements small parts system having and other larger for more flexible scheduling quality service. Hard techniques extremely pessimistic latter part application, consequently it is necessary use let resources be fully utilized achieve highest possible...

During the design phase of many real-time systems, designers often have a range acceptable period values for which some levels safety or quality service are guaranteed. The choice influences system schedulability and computational complexity analysis, especially rate monotonic (RM) scheduling algorithm. It has been shown that RM guarantees 100% utilization if periods harmonic, i.e., Each is an integer multiple shorter periods. In this paper, we address harmonic assignment problem where each...

Ethernet has become one of the most researched network technologies for modern, safety-critical, distributed systems due to its maturity and low cost. Standard Ethernet, however, is unsuitable safety-critical applications lack delivery guarantees delay bounds. The Time-Sensitive Networking (TSN) task group proposes several extensions address these shortcomings. One proposed Time-Aware Shaper (TAS, IEEE 802.1Qbv-2015) which introduces a gate mechanism that enables scheduled transmissions...

Low latency and on demand resource availability enable fog computing to host industrial applications in a cloud like manner. One domain which stands benefit from the advantages of is robotics. However, challenges developing implementing fog-based robotic system are manifold. To illustrate this, this paper we discuss involving robots robot cells at factory level, then highlight main building blocks necessary for achieving such functionality system. Further, elaborate an architecture, with...

This paper explores virtualization technologies and cloud computing for migrating an existing real-time safety-critical railway use-case from dedicated hardware solutions. Cloud is rapidly gaining popularity in many domains as they provide benefits such higher availability, scalability, efficient resource utilization. We examine deploying a (private) Real-Time(RT)-Cloud on COTS server to run while meeting stringent safety security requirements. base our migration review comparison relevant...

The requirements of industrial applications only rarely permit the exclusive use single paradigms in development real-time systems. Product cost, reuse existing solutions, and efficiency require diverse, or even opposing methods to coexist be integrated. In this paper, we deal with one problem encountered during a system for motion control automotive vehicles, integration static scheduling interrupts. user mandates pre run-time number reasons, e.g., predictability, testability low overhead....

Off-line scheduling and fixed priority (FPS) are often considered as complementing incompatible paradigms. A number of industrial applications demand temporal properties (predictability, jitter constraints, end-to-end deadlines, etc.) that typically achieved by using off-line scheduling. The rigid schemes used, however do not provide for flexibility. FPS has been widely studied used in a applications, mostly due to its simple run-time scheduling, small overhead. It can more flexibility, but...

The inherent properties of wireless sensor networks (WSN) disqualify most classic methods targeting timeliness guarantees. Assumptions such as well a restrictive notion borrowed from real-time systems clash with the indeterminism realistic scenarios. In this paper, we introduce generalized which allows to provide meaningful performance metrics under unreliable conditions, common in WSN. We present probabilistic metric capture level confidence for without restricting its applicability. It...

A number of algorithms have been presented for handling software decoding MPEG-2 streams based on buffering or rate adjustment focusing providing good average quality. The potentially arising drops in quality are tolerated, e.g., transmissions over the Internet; they cannot be accepted high consumer products: these mandate real-time methods. When resources, such as processing power network bandwidth, limited and not all frames can handled, best effort decoders incur unnecessary decrease...

The periodic task model has been widely used in real-time systems due to the behavior of many applications or observation patterns environmental events as control applications. While tasks some have inherent values for periods, can be defined via ranges acceptable values. designer choice period consequences w.r.t. To utilization set and resulting hyper period. Harmonic sets are favored, e.g., their polynomial-time worst case response time analysis small which is major concern visors...

The increasing application of flexible and powerful real-time distributed control systems is presently characterizing the industrial automation field. Such involve three main disciplines: systems, communication systems. Control due their stringent timing constraints, demand computing technology. In addition, are needed for data messaging between field devices. We propose an integrated approach to design implementation such show that by a separate its posterior implementation, system...

Fixed priority scheduling (FPS) has been widely studied and used in a number of applications, mostly due to its flexibility, simple run-time mechanism small overhead. However, preemption related overhead FPS may cause undesired high processor utilization, energy consumption, or, some cases, even infeasibility. In this paper, we propose method reduce the preemptions legacy systems consisting tasks with priorities, periods offsets. Unlike other approaches, our algorithm does not require...