Advanced flight control system study

A fly by wire flight control system architecture designed for high reliability includes spare sensor and computer elements to permit safe dispatch with failed elements, thereby reducing unscheduled maintenance. A methodology capable of demonstrating that the architecture does achieve the predicted performance characteristics consists of a hierarchy of activities ranging from analytical calculations of system reliability and formal methods of software verification to iron bird testing followed by flight evaluation. Interfacing this architecture to the Lockheed S-3A aircraft for flight test is discussed. This testbed vehicle can be expanded to support flight experiments in advanced aerodynamics, electromechanical actuators, secondary power systems, flight management, new displays, and air traffic control concepts

Validate implementation correctness using simulation: the TASTE approach

High-integrity systems operate in hostile environment and must guarantee a continuous operational state, even if unexpected events happen. In addition, these systems have stringent requirements that must be validated and correctly translated from high-level specifications down to code. All these constraints make the overall development process more time-consuming. This becomes especially complex because the number of system functions keeps increasing over the years. As a result, engineers must validate system implementation and check that its execution conforms to the specifications. To do so, a traditional approach consists in a manual instrumentation of the implementation code to trace system activity while operating. However, this might be error-prone because modifications are not automatic and still made manually. Furthermore, such modifications may have an impact on the actual behavior of the system. In this paper, we present an approach to validate a system implementation by comparing execution against simulation. In that purpose, we adapt TASTE, a set of tools that eases system development by automating each step as much as possible. In particular, TASTE automates system implementation from functional (system functions description with their properties – period, deadline, priority, etc.) and deployment(processors, buses, devices to be used) models. We tailored this tool-chain to create traces during system execution. Generated output shows activation time of each task, usage of communication ports (size of the queues, instant of events pushed/pulled, etc.) and other relevant execution metrics to be monitored. As a consequence, system engineers can check implementation correctness by comparing simulation and execution metrics

Closing the Digital Divide: Understanding Organizational Approaches to Digital Accessibility in Higher Education

Digital accessibility practices are becoming standardized in higher education as institutions seek to meet compliance with federal and state equal access laws. Students with disabilities have equal rights to access university programs and services in digital format. The widespread use of assistive technology, artificial intelligence, and content available in digital format brings forth ethical and legal concerns about equal access for individuals with disabilities. While broad approaches to digital accessibility in higher education are in the literature, there is a growing need for more studies to examine comprehensive approaches to digital accessibility across multiple units, disciplines, and the organization\u27s hierarchy. This case study examined individual participant interviews from 14 practitioners in different units and publicly available data to analyze how digital accessibility is addressed at three medium-sized public institutions of higher. During the inductive coding process, five main themes emerged related to implementing digital accessibility across the institutions, how it relates to people, practices, policies, and planning, and the larger body of literature on digital accessibility. The findings show there is no one-size-fits-all approach to digital accessibility. Institutions in higher education are motivated by risk management and compliance. A centralized and coordinated approach led to more organized efforts. Initiatives were largely led from the middle-level hierarchy. The availability of resources and funding affected the effectiveness of implementation efforts. The consistency of communication and uniformity of training affected the adoption of practices. Technology toolkits influenced the adoption of practices. Institutional policies and standards guided practices. Recommendations include prioritizing digital accessibility and student needs by designating a head of accessibility, coordinating efforts across units, centralizing processes, avoiding technology-only solutions, adopting the Higher Education Community Vendor Assessment Tool (HECVAT), and enacting an official policy that drives practices, expanding training for faculty, and providing consistent assistive technology support for students. An overall institutional coordinated plan for digital accessibility could lead to consistent and regular communication about policies and procedures and provide for a system of metrics and benchmarks