Source-level runtime validation through interval temporal logic

The high degree of software complexity achievable through current software development practices makes software more prone to failure. A number of work and work practices has evolved in order to reduce risks related to software correctness and reliability. One of which is validation, which monitors the system execution at runtime and verifies that the system states entered are valid according to the behavioural specification. This paper describes a framework providing an assertion like validation environment for integrating software properties specified in interval temporal logic. The framework consists in three parts. The first part provides a mechanism for converting the human readable assertion to a symbolic automata, which is then used by the second part of the framework that performs the validation.peer-reviewe

Automated verification of model-based programs under uncertainty

Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 89-91).Highly robust embedded systems have been enabled through software executives that have the ability to reason about their environment. Those that employ the model-based autonomy paradigm automatically diagnose and plan future actions, based on models of themselves and their environment. This includes autonomous systems that must operate in harsh and dynamic environments, like, deep space. Such systems must be robust to a large space of possible failure scenarios. This large state space poses difficulties for traditional scenario-based testing, leading to a need for new approaches to verification and validation. We propose a novel verification approach that generates an analysis of the most likely failure scenarios for a model-based program. By finding only the lost likely failures, we increase the relevance and reduce the quantity of information the developer must examine. First, we provide the ability to verify a stochastic system that encodes both off-nominal and nominal scenarios. We incorporate uncertainty into the verification process by acknowledging that all such programs may fail, but in different ways, with different likelihoods. The verification process is one of finding the most likely executions that fail the specification. Second, we provide a capability for verifying executable specifications that are fault-aware. We generalize offline plant model verification to the verification of model-based programs, which consist of both a plant model that captures the physical plant's nominal and off-nominal states and a control program that specifies its desired behavior. Third, we verify these specifications through execution of the RMPL executive itself. We therefore circumvent the difficulty of formalizing the behavior of complex(cont.) software executives. We present the RMPL Verifier, a tool for verification of model-based programs written in the Reactive Model-based Programming Language (RMPL) for the Titan execution kernel. Using greedy forward-directed search, this tool finds as counterexamples to the program's goal specification the most likely executions that do not achieve the goal within a given time bound.by Tazeen Mahtab.M.Eng.and S.B

Earth Observations and the Role of UAVs: A Capabilities Assessment

This three-volume document, based on the draft document located on the website given on page 6, presents the findings of a NASA-led capabilities assessment of Uninhabited Aerial Vehicles (UAVs) for civil (defined as non-DoD) use in Earth observations. Volume 1 is the report that presents the overall assessment and summarizes the data. The second volume contains the appendices and references to address the technologies and capabilities required for viable UAV missions. The third volume is the living portion of this effort and contains the outputs from each of the Technology Working Groups (TWGs) along with the reviews conducted by the Universities Space Research Association (USRA). The focus of this report, intended to complement the Office of the Secretary of Defense UAV Roadmap, is four-fold: 1) To determine and document desired future Earth observation missions for all UAVs based on user-defined needs; 2) To determine and document the technologies necessary to support those missions; 3) To discuss the present state of the art platform capabilities and required technologies, including identifying those in progress, those planned, and those for which no current plans exist; 4) Provide the foundations for development of a comprehensive civil UAV roadmap. It is expected that the content of this report will be updated periodically and used to assess the feasibility of future missions. In addition, this report will provide the foundation to help influence funding decisions to develop those technologies that are considered enabling or necessary but are not contained within approved funding plans. This document is written such that each section will be supported by an Appendix that will give the reader a more detailed discussion of that section's topical materials

Earth Observations and the Role of UAVs: A Capabilities Assessment

This document provides an assessment of the civil UAV missions and technologies and is intended to parallel the Office of the Secretary of Defense UAV Roadmap. The intent of this document is four-fold: 1. Determine and document desired future missions of Earth observation UAVs based on user-defined needs 2. Determine and document the technologies necessary to support those missions 3. Discuss the present state of the platform capabilities and required technologies, identifying those in progress, those planned, and those for which no current plans exist 4. Provide the foundations for development of a comprehensive civil UAV roadmap to complement the Department of Defense (DoD) effort (http://www.acq.osd.mil/uas/). Two aspects of the President's Management Agenda (refer to the document located at: www.whitehouse.gov/omb/budget/fy2002/mgmt.pdf ) are supported by this undertaking. First, it is one that will engage multiple Agencies in the effort as stakeholders and benefactors of the systems. In that sense, the market will be driven by the user requirements and applications. The second aspect is one of supporting economic development in the commercial sector. Market forecasts for the civil use of UAVs have indicated an infant market stage at present with a sustained forecasted growth. There is some difficulty in quantifying the value of the market since the typical estimate excludes system components other than the aerial platforms. Section 2.4 addresses the civil UAV market forecast and lists several independent forecasts. One conclusion that can be drawn from these forecasts is that all show a sustained growth for the duration of each long-term forecast