Requirements traceability in model-driven development: Applying model and transformation conformance

The variety of design artifacts (models) produced in a model-driven design process results in an intricate relationship between requirements and the various models. This paper proposes a methodological framework that simplifies management of this relationship, which helps in assessing the quality of models, realizations and transformation specifications. Our framework is a basis for understanding requirements traceability in model-driven development, as well as for the design of tools that support requirements traceability in model-driven development processes. We propose a notion of conformance between application models which reduces the effort needed for assessment activities. We discuss how this notion of conformance can be integrated with model transformations

Safeguard: Progress and Test Results for a Reliable Independent On-Board Safety Net for UAS

As demands increase to use unmanned aircraft systems (UAS) for a broad spectrum of commercial applications, regulatory authorities are examining how to safely integrate them without compromising safety or disrupting traditional airspace operations. For small UAS, several operational rules have been established; e.g., do not operate beyond visual line-of-sight, do not fly within five miles of a commercial airport, do not fly above 400 feet above ground level. Enforcing these rules is challenging for UAS, as evidenced by the number of incident reports received by the Federal Aviation Administration (FAA). This paper reviews the development of an onboard system - Safeguard - designed to monitor and enforce conformance to a set of operational rules defined prior to flight (e.g., geospatial stay-out or stay-in regions, speed limits, and altitude constraints). Unlike typical geofencing or geo-limitation functions, Safeguard operates independently of the off-the-shelf UAS autopilot and is designed in a way that can be realized by a small set of verifiable functions to simplify compliance with existing standards for safety-critical systems (e.g. for spacecraft and manned commercial transportation aircraft systems). A framework is described that decouples the system from any other devices on the UAS as well as introduces complementary positioning source(s) for applications that require integrity and availability beyond what can be provided by the Global Positioning System (GPS). This paper summarizes the progress and test results for Safeguard research and development since presentation of the design concept at the 35th Digital Avionics Systems Conference (DASC '16). Significant accomplishments include completion of software verification and validation in accordance with NASA standards for spacecraft systems (to Class B), development of improved hardware prototypes, development of a simulation platform that allows for hardware-in-the-loop testing and fast-time Monte Carlo evaluations, and flight testing on multiple air vehicles. Integration testing with NASA's UAS Traffic Management (UTM) service-oriented architecture was also demonstrated

EMERGING TECHNOLOGIES: COMMERCIAL READINESS INDEX (CRI) FOR MEDICAL ADDITIVE MANUFACTURING (AM)

ArticleTechnology Readiness Level (TRL) is widely used as a measure of technology maturity. However, TRL is not necessarily a good indicator of commercial readiness. In the renewable energy sector a Commercial Readiness Index (CRI) is used where only a technology with a high TRL qualifies for commercial readiness. Similarly TRL is used to measure the maturity of Additive Manufacturing (AM) technologies. This research proposes a Commercial Readiness Index (CRI) for Additive Manufacturing. A case-study on maxillofacial Ti6Al4V implants manufactured with AM is referred to

Modeling families of public licensing services: a case study

Software Product Lines (SPLs) enable the development of families of software systems by taking advantage of the commonalities and variabilities of the members of the family. Despite its many advantages, it is an unexplored area in the electronic government domain, an area with evident families of services, and with high demands to develop faster and better services to citizens and businesses while reducing costs. This paper discusses the need of formal methods to model SPLs for such domain. It presents a case study of a family of public licensing services modeled in UPPAAL and based on Featured Timed Automata, an extension of Timed Automata to model realtime SPLs. It analyzes the suitability of FTA to model distributed families of services, while provides hints on a possible enrichment of FTA to better support modularization and compositionality of services.This work is part of the project SMARTEGOV: Harnessing EGOV for Smart Governance (Foundations, Methods, Tools) / NORTE-01-0145-FEDER-000037, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The first author is further supported by FCT under grant PD/BD/52238/2013

An Analytical Model for Wireless Mesh Networks with Collision-Free TDMA and Finite Queues

Wireless mesh networks are a promising technology for connecting sensors and actuators with high flexibility and low investment costs. In industrial applications, however, reliability is essential. Therefore, two time-slotted medium access methods, DSME and TSCH, were added to the IEEE 802.15.4 standard. They allow collision-free communication in multi-hop networks and provide channel hopping for mitigating external interferences. The slot schedule used in these networks is of high importance for the network performance. This paper supports the development of efficient schedules by providing an analytical model for the assessment of such schedules, focused on TSCH. A Markov chain model for the finite queue on every node is introduced that takes the slot distribution into account. The models of all nodes are interconnected to calculate network metrics such as packet delivery ratio, end-to-end delay and throughput. An evaluation compares the model with a simulation of the Orchestra schedule. The model is applied to Orchestra as well as to two simple distributed scheduling algorithms to demonstrate the importance of traffic-awareness for achieving high throughput.Comment: 17 pages, 14 figure

Trusted product lines

This thesis describes research undertaken into the application of software product line approaches to the development of high-integrity, embedded real-time software systems that are subject to regulatory approval/certification. The motivation for the research arose from a real business need to reduce cost and lead time of aerospace software development projects. The thesis hypothesis can be summarised as follows: It is feasible to construct product line models that allow the specification of required behaviour within a reference architecture that can be transformed into an effective product implementation, whilst enabling suitable supporting evidence for certification to be produced. The research concentrates on the following four main areas: 1. Construction of an argument framework in which the application of product line techniques to high-integrity software development can be assessed and critically reviewed. 2. Definition of a product-line reference architecture that can host components containing variation. 3. Design of model transformations that can automatically instantiate products from a set of components hosted within the reference architecture. 4. Identification of verification approaches that may provide evidence that the transformations designed in step 3 above preserve properties of interest from the product line model into the product instantiations. Together, these areas form the basis of an approach we term “Trusted Product Lines”. The approach has been evaluated and validated by deployment on a real aerospace project; the approach has been used to produce DO-178B/ED-12B Level A applications of over 300 KSLOC in size. The effect of this approach on the software development process has been critically evaluated in this thesis, both quantitatively (in terms of cost and relative size of process phases) and qualitatively (in terms of software quality). The “Trusted Product Lines” approach, as described within the thesis, shows how product line approaches can be applied to high-integrity software development, and how certification evidence created and arguments constructed for products instantiated from the product line. To the best of our knowledge, the development and effective application of product line techniques in a certification environment is novel and unique