System Engineering Strategy for Distributed Multi-Purpose Simulation Architectures

This paper describes the system engineering approach used to develop distributed multi-purpose simulations. The multi-purpose simulation architecture focuses on user needs, operations, flexibility, cost and maintenance. This approach was used to develop an International Space Station (ISS) simulator, which is called the International Space Station Integrated Simulation (ISIS)1. The ISIS runs unmodified ISS flight software, system models, and the astronaut command and control interface in an open system design that allows for rapid integration of multiple ISS models. The initial intent of ISIS was to provide a distributed system that allows access to ISS flight software and models for the creation, test, and validation of crew and ground controller procedures. This capability reduces the cost and scheduling issues associated with utilizing standalone simulators in fixed locations, and facilitates discovering unknowns and errors earlier in the development lifecycle. Since its inception, the flexible architecture of the ISIS has allowed its purpose to evolve to include ground operator system and display training, flight software modification testing, and as a realistic test bed for Exploration automation technology research and development

Space-Based Reconfigurable Software Defined Radio Test Bed Aboard International Space Station

The National Aeronautical and Space Administration (NASA) recently launched a new software defined radio research test bed to the International Space Station. The test bed, sponsored by the Space Communications and Navigation (SCaN) Office within NASA is referred to as the SCaN Testbed. The SCaN Testbed is a highly capable communications system, composed of three software defined radios, integrated into a flight system, and mounted to the truss of the International Space Station. Software defined radios offer the future promise of in-flight reconfigurability, autonomy, and eventually cognitive operation. The adoption of software defined radios offers space missions a new way to develop and operate space transceivers for communications and navigation. Reconfigurable or software defined radios with communications and navigation functions implemented in software or VHDL (Very High Speed Hardware Description Language) provide the capability to change the functionality of the radio during development or after launch. The ability to change the operating characteristics of a radio through software once deployed to space offers the flexibility to adapt to new science opportunities, recover from anomalies within the science payload or communication system, and potentially reduce development cost and risk by adapting generic space platforms to meet specific mission requirements. The software defined radios on the SCaN Testbed are each compliant to NASA's Space Telecommunications Radio System (STRS) Architecture. The STRS Architecture is an open, non-proprietary architecture that defines interfaces for the connections between radio components. It provides an operating environment to abstract the communication waveform application from the underlying platform specific hardware such as digital-to-analog converters, analog-to-digital converters, oscillators, RF attenuators, automatic gain control circuits, FPGAs, general-purpose processors, etc. and the interconnections among different radio components

Evaluation of structured questions using modified BLEU algorithm

This paper describes and exemplifies an application of a Structured Exam Questions Test Bank and Evaluation Using Modified Bilingual Evaluation Understudy (BLEU) Algorithm, a software system developed in pursuit of robust computerized marking of free-text answers to open-ended questions.It employs the Information System Development Research Methodology with modified BLEU Algorithm and Expert System for similar words.The system was developed to facilitate in managing and administrating structured questions for client/server architecture based on intranet. The system incorporates a number of processing modules specifically aim at providing an automated marking to reduce spelling errors, calculating scores, managing and administrating an exam.The system was trial-run by a group of students and lecturers, and modifications particularly on the interface have been modified and implemented. Problems and limitations discovered were then discussed and recommendations made to overcome the limitations for the future development of the research

Formal Modelling, Testing and Verification of HSA Memory Models using Event-B

The HSA Foundation has produced the HSA Platform System Architecture Specification that goes a long way towards addressing the need for a clear and consistent method for specifying weakly consistent memory. HSA is specified in a natural language which makes it open to multiple ambiguous interpretations and could render bugs in implementations of it in hardware and software. In this paper we present a formal model of HSA which can be used in the development and verification of both concurrent software applications as well as in the development and verification of the HSA-compliant platform itself. We use the Event-B language to build a provably correct hierarchy of models from the most abstract to a detailed refinement of HSA close to implementation level. Our memory models are general in that they represent an arbitrary number of masters, programs and instruction interleavings. We reason about such general models using refinements. Using Rodin tool we are able to model and verify an entire hierarchy of models using proofs to establish that each refinement is correct. We define an automated validation method that allows us to test baseline compliance of the model against a suite of published HSA litmus tests. Once we complete model validation we develop a coverage driven method to extract a richer set of tests from the Event-B model and a user specified coverage model. These tests are used for extensive regression testing of hardware and software systems. Our method of refinement based formal modelling, baseline compliance testing of the model and coverage driven test extraction using the single language of Event-B is a new way to address a key challenge facing the design and verification of multi-core systems.Comment: 9 pages, 10 figure

Diagnosis and Prognosis of Weapon Systems

The Prognostics Framework is a set of software tools with an open architecture that affords a capability to integrate various prognostic software mechanisms and to provide information for operational and battlefield decision-making and logistical planning pertaining to weapon systems. The Prognostics NASA Tech Briefs, February 2005 17 Framework is also a system-level health -management software system that (1) receives data from performance- monitoring and built-in-test sensors and from other prognostic software and (2) processes the received data to derive a diagnosis and a prognosis for a weapon system. This software relates the diagnostic and prognostic information to the overall health of the system, to the ability of the system to perform specific missions, and to needed maintenance actions and maintenance resources. In the development of the Prognostics Framework, effort was focused primarily on extending previously developed model-based diagnostic-reasoning software to add prognostic reasoning capabilities, including capabilities to perform statistical analyses and to utilize information pertaining to deterioration of parts, failure modes, time sensitivity of measured values, mission criticality, historical data, and trends in measurement data. As thus extended, the software offers an overall health-monitoring capability

Towards an Open, Distributed Software Architecture for UxS Operations

To address the growing need to evaluate, test, and certify an ever expanding ecosystem of UxS platforms in preparation of cultural integration, NASA Langley Research Center's Autonomy Incubator (AI) has taken on the challenge of developing a software framework in which UxS platforms developed by third parties can be integrated into a single system which provides evaluation and testing, mission planning and operation, and out-of-the-box autonomy and data fusion capabilities. This software framework, named AEON (Autonomous Entity Operations Network), has two main goals. The first goal is the development of a cross-platform, extensible, onboard software system that provides autonomy at the mission execution and course-planning level, a highly configurable data fusion framework sensitive to the platform's available sensor hardware, and plug-and-play compatibility with a wide array of computer systems, sensors, software, and controls hardware. The second goal is the development of a ground control system that acts as a test-bed for integration of the proposed heterogeneous fleet, and allows for complex mission planning, tracking, and debugging capabilities. The ground control system should also be highly extensible and allow plug-and-play interoperability with third party software systems. In order to achieve these goals, this paper proposes an open, distributed software architecture which utilizes at its core the Data Distribution Service (DDS) standards, established by the Object Management Group (OMG), for inter-process communication and data flow. The design decisions proposed herein leverage the advantages of existing robotics software architectures and the DDS standards to develop software that is scalable, high-performance, fault tolerant, modular, and readily interoperable with external platforms and software

Trust Management and Security in Satellite Telecommand Processing

New standards and initiatives in satellite system architecture are moving the space industry to more open and efficient mission operations. Primarily, these standards allow multiple missions to share standard ground and space based resources to reduce mission development and sustainment costs. With the benefits of these new concepts comes added risk associated with threats to the security of our critical space assets in a contested space and cyberspace domain. As one method to mitigate threats to space missions, this research develops, implements, and tests the Consolidated Trust Management System (CTMS) for satellite flight software. The CTMS architecture was developed using design requirements and features of Trust Management Systems (TMS) presented in the field of distributed information systems. This research advances the state of the art with the CTMS by refining and consolidating existing TMS theory and applying it to satellite systems. The feasibility and performance of this new CTMS architecture is demonstrated with a realistic implementation in satellite flight software and testing in an emulated satellite system environment. The system is tested with known threat modeling techniques and a specific forgery attack abuse case of satellite telecommanding functions. The CTMS test results show the promise of this technique to enhance security in satellite flight software telecommand processing. With this work, a new class of satellite protection mechanisms is established, which addresses the complex security issues facing satellite operations today. This work also fills a critical shortfall in validated security mechanisms for implementation in both public and private sector satellite systems

Embedded control system for autarep - a novel autonomous articulated robotic educational platform

This research introduces an open-source framework, AUTonomous Articulated Robotic Educational Platform (AUTAREP). The platform is centred on a 6 Degree Of Freedom (DOF) arm with multiple feedbacks to ensure precision and autonomy. The sensory system consists of vision, position and force feedbacks while the actuation system comprises six precise DC servo motors. In particular, this paper presents the design of an embedded controller for AUTAREP. The proposed design of the control hardware and software interface has been tailored as per academic requirements of relevant undergraduate and postgraduate courses. Low level commands have been provided to permit readily development of applications for trainees. Advanced users can further exploit the open-source architecture of the platform. The performance of the proposed control system has been demonstrated by various experiments on the fabricated hardware. The control has been subjected to various test inputs to analyse its transient and steady state behaviour. The robot has been tested to achieve a set-point position successfully and the encoder data corresponding to all the joints has been recorded. Finally, a common application of "pick and place" has been implemented. The proposed platform is potentially beneficial in teaching engineering courses, training in industrial sector and research of advanced algorithms

The Fascinator: A lightweight, modular contribution to the Fedora-commons world

4th International Conference on Open RepositoriesThis presentation was part of the session : Fedora User Group PresentationsDate: 2009-05-20 01:30 PM – 03:00 PMThe Australian government has supported the development of repository infrastructure for several years now. One product of this support was the ARROW project (Australian Research Repositories Online to the World). The ARROW project sponsored a hybrid commercial/open-source approach to building vendor-supported repository infrastructure with open-source underpinnings. One of the open-source contributions, which complements the vendor-sourced product adopted by many of the ARROW partners is a simple to install and configure front-end web service for Fedora repositories known as "The Fascinator". The Fascinator was conceived initially as a way to prove a point in an ongoing dialogue within the ARROW project about repository architecture. The goal was to test the hypothesis that it would be possible to build a useful, fast, flexible web front end for a repository using a single fast indexing system to handle browsing via facets, full-text search, multiple 'portal' views of subsets of a large corpus, and most importantly, easy-to administer security that could handle the most common uses cases seen in the ARROW community. This contrasted with the approach taken by ARROW's commercial partner, which used several different indices to achieve only some of the same functionality in an environment which was much more complex to manage and configure. We will give an overview of the product in both functional and technical terms. Functionally, The Fascinator offers: Click-to-create portals. Easy to configure security based on a query-based filter system, the repository owner can express security in terms of saved-searches that define what a user or group is allowed to see. Highly flexible indexing of a Fedora repository for administrators (and by extension anything the harvesting module can scrape-up). Technically, The Fascinator is a modular system, written in Java so it is easy to deploy with Fedora and Solr, consisting of: An indexing system for Fedora which builds on the standard G-Search supplied with the software, and some work done by the Muradora team. A configurable harvesting application which can ingest data from OAI-PMH, ORE, and local file systems. A web portal application which can be used to build flexible front end websites or act as a service to other sites via an HTTP API. An OAI-PMH (and ATOM archive) system which can create sub-feeds from a repository very easily without complexities like OAI-PMH sets. An easy to use installer for Unix based platforms allowing a systems administrator to install the application along with Fedora and Solr with a few keystrokes. While The Fascinator's goals were modest it has been met with some enthusiasm by repository managers in Australia and beyond, and is being trialled and/or piloted in a small number of sites across the world.ARROW project, Monash Universit

Property-based testing for the robot operating system

The Robot Operating System (ROS) is an open source framework for the development of robotic software, in which a typical system consists of multiple processes communicating under a publisher-subscriber architecture. A great deal of development time goes into orchestration and making sure that the communication interfaces comply with the expected contracts (e.g. receiving a message leads to the publication of another message). Orchestration mistakes are only detected during runtime, stressing the importance of component and integration testing in the verification process. Property-based Testing is fitting in this context, since it is based on the specification of contracts and treats tested components as black boxes, but there is no support for it in ROS. In this paper, we present a first approach towards automatic generation of test scripts for property-based testing of various configurations of a ROS system.The authors would like to thank the anonymous referees for their valuable comments and helpful suggestions. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia within project PTDC/CCI-INF/29583/2017 (POCI-01-0145-FEDER-029583)