Schedulability-Driven Frame Packing for Multi-Cluster Distributed Embedded Systems

We present an approach to frame packing for multi-cluster distributed embedded systems consisting of time-triggered and event-triggered clusters, interconnected via gateways. In our approach, the application messages are packed into frames such that the application is schedulable. Thus, we have also proposed a schedulability analysis for applications consisting of mixed event-triggered and time-triggered processes and messages, and a worst case queuing delay analysis for the gateways, responsible for routing inter-cluster traffic. Optimization heuristics for frame packing aiming at producing a schedulable system have been proposed. Extensive experiments and a real-life example show the efficiency of our frame-packing approach

Enhancing real-time CAN communications by the prioritization of urgent messages at the outgoing queue

To ensure the correct behaviour of a Networked Control System, the communication network mustprovide a reliable and timely communication service. The two components with the highest impact on thecommunication delays are the Medium Access Control (MAC) protocol and the local communication stack,therefore, the usage of an adequate communication stack is of utmost importance to guarantee the timingcorrectness of a feedback control application.In this paper, we propose the use of state-of-the-art scheduling algorithms to manage the outgoing queue of alocal communication stack. We demonstrate that it is possible to improve the responsiveness of applicationssupported by the CAN communication protocol, by using just a light scheduling middleware to adequatelyschedule the outgoing queue. We also show that implementing such middleware even on top of COTScommunication hardware, opens the possibility to enhance the communication process by minimizing thenumber of deadline misses for highly loaded network scenarios

Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)

An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined

Schedulability Analysis and Optimization for the Synthesis of Multi-Cluster Distributed Embedded Systems

Abstract 1 We present an approach to schedulability analysis for the synthesis of multi-cluster distributed embedded systems consisting of timetriggered and event-triggered clusters, interconnected via gateways. We have also proposed a buffer size and worst case queuing delay analysis for the gateways, responsible for routing inter-cluster traffic. Optimization heuristics for the priority assignment and synthesis of bus access parameters aimed at producing a schedulable system with minimal buffer needs have been proposed. Extensive experiments and a real-life example show the efficiency of our approaches. 1

Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 2: Army fault tolerant architecture design and analysis

Described here is the Army Fault Tolerant Architecture (AFTA) hardware architecture and components and the operating system. The architectural and operational theory of the AFTA Fault Tolerant Data Bus is discussed. The test and maintenance strategy developed for use in fielded AFTA installations is presented. An approach to be used in reducing the probability of AFTA failure due to common mode faults is described. Analytical models for AFTA performance, reliability, availability, life cycle cost, weight, power, and volume are developed. An approach is presented for using VHSIC Hardware Description Language (VHDL) to describe and design AFTA's developmental hardware. A plan is described for verifying and validating key AFTA concepts during the Dem/Val phase. Analytical models and partial mission requirements are used to generate AFTA configurations for the TF/TA/NOE and Ground Vehicle missions

Verification of automotive networks - what to expect (and not expect) from each technique

The presentation focuses on the verification of wired automotive buses and addresses the following topics: historical perspective of verification techniques, review of the different sets of messages and verification techniques along the development cycle, performance metrics and end-to-end constraints, early stage verification technique: schedulability analysis versus simulation

SatCat5: A Low-Power, Mixed-Media Ethernet Network for Smallsats

In any satellite, internal bus and payload systems must exchange a variety of command, control, telemetry, and mission-data. In too many cases, the resulting network is an ad-hoc proliferation of complex, dissimilar protocols with incomplete system-to-system connectivity. While standards like CAN, MIL-STD-1553, and SpaceWire mitigate this problem, none can simultaneously solve the need for high throughput and low power consumption. We present a new solution that uses Ethernet framing and addressing to unify a mixed-media network. Low-speed nodes (0.1-10 Mbps) use simple interfaces such as SPI and UART to communicate with extremely low power and minimal complexity. High-speed nodes use so-called “media-independent” interfaces such as RMII, RGMII, and SGMII to communicate at rates up to 1000 Mbps and enable connection to traditional COTS network equipment. All are interconnected into a single smallsat-area-network using a Layer-2 network switch, with mixed-media support for all these interfaces on a single network. The result is fast, easy, and flexible communication between any two subsystems. SatCat5 is presented as a free and open-source reference implementation of this mixed-media network switch, with power consumption of 0.2-0.7W depending on network activity. Further discussion includes example protocols that can be used on such networks, leveraging IPv4 when suitable but also enabling full-featured communication without the need for a complex protocol stack

The LVLASO I/O Concentrator Software Description

This paper describes the software written for the VO Concentrator Unit in support of the Low Visibility Landing and Surface Operations (LVLASO) experiment flown on-board NASA's Boeing 757 aircraft