399 research outputs found

    Tracing Hardware Monitors in the GR712RC Multicore Platform: Challenges and Lessons Learnt from a Space Case Study

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    The demand for increased computing performance is driving industry in critical-embedded systems (CES) domains, e.g. space, towards the use of multicores processors. Multicores, however, pose several challenges that must be addressed before their safe adoption in critical embedded domains. One of the prominent challenges is software timing analysis, a fundamental step in the verification and validation process. Monitoring and profiling solutions, traditionally used for debugging and optimization, are increasingly exploited for software timing in multicores. In particular, hardware event monitors related to requests to shared hardware resources are building block to assess and restraining multicore interference. Modern timing analysis techniques build on event monitors to track and control the contention tasks can generate each other in a multicore platform. In this paper we look into the hardware profiling problem from an industrial perspective and address both methodological and practical problems when monitoring a multicore application. We assess pros and cons of several profiling and tracing solutions, showing that several aspects need to be taken into account while considering the appropriate mechanism to collect and extract the profiling information from a multicore COTS platform. We address the profiling problem on a representative COTS platform for the aerospace domain to find that the availability of directly-accessible hardware counters is not a given, and it may be necessary to the develop specific tools that capture the needs of both the user’s and the timing analysis technique requirements. We report challenges in developing an event monitor tracing tool that works for bare-metal and RTEMS configurations and show the accuracy of the developed tool-set in profiling a real aerospace application. We also show how the profiling tools can be exploited, together with handcrafted benchmarks, to characterize the application behavior in terms of multicore timing interference.This work has been partially supported by a collaboration agreement between Thales Research and the Barcelona Supercomputing Center, and the European Research Council (ERC) under the EU’s Horizon 2020 research and innovation programme (grant agreement No. 772773). MINECO partially supported Jaume Abella under Ramon y Cajal postdoctoral fellowship (RYC2013-14717).Peer ReviewedPostprint (published version

    Using Helmet Mounted Displays to Designate and Locate Targets in the Urban Environment

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    Technologies have developed within the last ten years to allow the Helmet Mounted Display (HMD) to be much more effective as an air-to-ground (A/G) weapons cue. HMD A/G accuracy and performance requirements should be added to the Joint Helmet Mounted Cueing System (JHMCS) specifications, detailed to be as good or better than the FA-18 heads-up-display (HUD). Because of target ranging and line-of-sight (LOS) errors, the JHMCS is only used as an area sensor cue in the urban close air support (CAS) role. Therefore, for use against point targets, improvements to JHMCS are needed. LOS errors have to be reduced from the current 13-mil error, which would equate to +/- 260 feet from a 20,000 ft slant range. To decrease this error, more accurate helmet trackers must be used with faster update rates. HMD Earth referenced symbol update rates, which are currently restricted to 20 Hz, must be increased to allow the helmet to provide accurate information, despite aggressive maneuvering or operations in a turbulent environment. Accurate ranging sources must be developed to enhance the target elevation algorithm in the FA-18 to ensure usable target data, once designations are made. During turbulent flight conditions, the difference between the actual target position on the ground and the unstable target designation (TD) diamond depicting it cause motion differences, which distract the pilot. Methods to filter the movement of earth-referenced symbols should be explored, as well as increasing JHMCS symbol write rates. Additionally, vibration levels during low-level flight and moderate turbulence levels make HMD A/G aiming and designation tasks very difficult. Buffet suppression algorithms are used during vibrations in the air-to-air (A/A) aiming role and should be implemented for A/G use as well. The purpose of this study is to focus on present capabilities with JHMCS. The author’s tactical experience has been achieved on the FA-18 A-F variants and tactical applicability will be directed to that platform. While most references to helmet displays will center on lessons learned from the JHMCS, helmet mounted display experience was gained while serving as an exchange officer with the UK Royal Air Force and evaluating the Guardian HMD system. The analysis contained within this thesis is based on the operational insights of operating within the demanding Close Air Support (CAS) environment and the tactical enhancement that has been demonstrated with the use of Helmet Mounted Cueing systems. Currently, JHMCS is available to about half the FA-18 fleet and operational assessments, resulting from its use in the Iraqi conflict, has accelerated the demand for increased capabilities to this target cueing device. Lessons learned from the current generation of HMDs will play a major role in the design of the cockpit for the Joint Strike Fighter (JSF)

    Undergraduate Catalog of Studies, 2023-2024

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    Undergraduate Catalog of Studies, 2023-2024

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    Security in Digital Aeronautical Communications A Comprehensive Gap Analysis

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    Aeronautical communications still heavily depend on analog radio systems, despite the fact that digital communication has been introduced to aviation in the 1990's. Since then, the digitization of civil aviation has been continued, as considerable pressure to rationalize the aeronautical spectrum has built up. In any modern digital communications system, the threat of digital attacks needs to be considered carefully. This is especially true for safety-critical infrastructure, which aviation's operational communication services clearly are. In this article, we reverse the traditional approach in the aeronautical industry of looking at a system from the safety perspective and assume a security-oriented point of view. We use the lens of security properties to review the requirements and specifications of aeronautical communications infrastructure as of 2021 and observe that most standards lack cybersecurity as a key requirement. Furthermore, we review the academic literature to identify possible solutions for the lack of cybersecurity measures in aeronautical communications system. We observe that most systems have been thoroughly analyzed within the academic security community, some for decades even, with many papers proposing concrete solutions to missing cybersecurity features. We conclude that there is a systematic problem in the design process of aeronautical communication systems. We provide a list of eight key findings and recommendations to improve the process of specifying such systems in a secure manner

    Autonomous Collision avoidance for Unmanned aerial systems

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    Unmanned Aerial System (UAS) applications are growing day by day and this will lead Unmanned Aerial Vehicle (UAV) in the close future to share the same airspace of manned aircraft.This implies the need for UAS to define precise safety standards compatible with operations standards for manned aviation. Among these standards the need for a Sense And Avoid (S&A) system to support and, when necessary, sub¬stitute the pilot in the detection and avoidance of hazardous situations (e.g. midair collision, controlled flight into terrain, flight path obstacles, and clouds). This thesis presents the work come out in the development of a S&A system taking into account collision risks scenarios with multiple moving and fixed threats. The conflict prediction is based on a straight projection of the threats state in the future. The approximations introduced by this approach have the advantage of high update frequency (1 Hz) of the estimated conflict geometry. This solution allows the algorithm to capture the trajectory changes of the threat or ownship. The resolution manoeuvre evaluation is based on a optimisation approach considering step command applied to the heading and altitude autopilots. The optimisation problem takes into account the UAV performances and aims to keep a predefined minimum separation distance between UAV and threats during the resolution manouvre. The Human-Machine Interface (HMI) of this algorithm is then embedded in a partial Ground Control Station (GCS) mock-up with some original concepts for the indication of the flight condition parameters and the indication of the resolution manoeuvre constraints. Simulations of the S&A algorithm in different critical scenarios are moreover in-cluded to show the algorithm capabilities. Finally, methodology and results of the tests and interviews with pilots regarding the proposed GCS partial layout are covered

    Graduate Catalogue 2021-2022

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    https://scholarship.shu.edu/graduate_catalogues/1021/thumbnail.jp

    A Method to Define Requirements for System of Systems

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    The purpose of this research was to develop and apply a systems-based method for defining System of Systems (SoS) requirements using an inductive research design. Just as traditional Systems Engineering (TSE) includes a requirements definition phase, so too does System of Systems Engineering (SoSE); only with a wider, more over- arching, systemic perspective. TSE addresses the design and development of a single system with generally a very specific functional purpose enabled by any number of subcomponents. SoSE however, addresses the design and development of a large, complex system to meet a wide range of functional purposes enabled by any number of constituent systems, each of which may have its own individually-managed and funded TSE effort in execution. To date, the body of prescriptive guidance on how to define SoS requirements is extremely limited and nothing exists today that offers a methodological approach capable of being leveraged against real-world SoS problems. As a result, SoSE practitioners are left attempting to apply TSE techniques, methods, and tools to address requirements for the more complex problems of the SoS domain. This research addressed this gap in the systems body of knowledge by developing a method, grounded in systems principles and theory, that offers practitioners a systemic, flexible method for defining unifying and measurable SoS requirements. This provides element system managers and engineers a SoS focus to their efforts while still maximizing their autonomy to achieve system-level requirements. A rigorous mixed-method research methodology, employing inductive methods with a case application was used to develop and validate the SoS Requirements Definition Method. Two research questions provided the research focus: • How does the current body of knowledge inform the definition of a system theoretic construct to define SoS requirements? • What results from the demonstration of the candidate construct for SoS requirements definition? Using Discoverers \u27 Induction (Whewell, 1858), coupled with coding techniques from the grounded theory method (Glaser & Strauss, 1967), a systems-based method for defining SoS requirements was constructed and applied to a real-world SoS requirements definition case. The structured systemic method advances the SoSE field and shows significant promise for further development to support SoSE practitioners in the area of SoS requirements engineering
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