Design space exploration of a jet engine component using a combined object model for function and geometry

The design of aircraft and engine components hinges on the use of computer aided design (CAD) models and the subsequent geometry-based analyses for evaluation of the quality of a concept. However, the generation (and variation) of CAD models to include radical or novel design solutions is a resource intense modelling effort. While approaches to automate the generation and variation of CAD models exist, they neglect the capture and representation of the product’s design rationale—what the product is supposed to do. The design space exploration approach Function and Geometry Exploration (FGE) aims to support the exploration of more functionally and geometrically different product concepts under consideration of not only geometrical, but also teleological aspects. The FGE approach has been presented and verified in a previous presentation. However, in order to contribute to engineering design practice, a design method needs to be validated through application in industrial practice. Hence, this publication reports from a study where the FGE approach has been applied by a design team of a Swedish aerospace manufacturers in a conceptual product development project. Conceptually different alternatives were identified in order to meet the expected functionality of a guide vane (GV). The FGE was introduced and applied in a series of workshops. Data was collected through participatory observation in the design teams by the researchers, as well as interviews and questionnaires. The results reveal the potential of the FGE approach as a design support to: (1) Represent and capture the design rationale and the design space; (2) capture, integrate and model novel solutions; and (3) provide support for the embodiment of novel concepts that would otherwise remain unexplored. In conclusion, the FGE method supports designers to articulate and link the design rationale, including functional requirements and alternative solutions, to geometrical features of the product concepts. The method supports the exploration of alternative solutions as well as functions. However, scalability and robustness of the generated CAD models remain subject to further research

Zone-based formal specification and timing analysis of real-time self-adaptive systems

Self-adaptive software systems are able to autonomously adapt their behavior at run-time to react to internal dynamics and to uncertain and changing environment conditions. Formal specification and verification of self-adaptive systems are tasks generally very difficult to carry out, especially when involving time constraints. In this case, in fact, the system correctness depends also on the time associated with events. This article introduces the Zone-based Time Basic Petri nets specification formalism. The formalism adopts timed adaptation models to specify self-adaptive behavior with temporal constraints, and relies on a zone-based modeling approach to support separation of concerns. Zones identified during the modeling phase can be then used as modules either in isolation, to verify intra-zone properties, or all together, to verify inter-zone properties over the entire system. In addition, the framework allows the verification of (timed) robustness properties to guarantee self-healing capabilities when higher levels of reliability and availability are required to the system, especially when dealing with time-critical systems. This article presents also the ZAFETY tool, a Java software implementation of the proposed framework, and the validation and experimental results obtained in modeling and verifying two time-critical self-adaptive systems: the Gas Burner system and the Unmanned Aerial Vehicle system

Requirements Engineering

Requirements Engineering (RE) aims to ensure that systems meet the needs of their stakeholders including users, sponsors, and customers. Often consid- ered as one of the earliest activities in software engineering, it has developed into a set of activities that touch almost every step of the software development process. In this chapter, we reflect on how the need for RE was first recognised and how its foundational concepts were developed. We present the seminal papers on four main activities of the RE process, namely (i) elicitation, (ii) modelling & analysis, (iii) as- surance, and (iv) management & evolution. We also discuss some current research challenges in the area, including security requirements engineering as well as RE for mobile and ubiquitous computing. Finally, we identify some open challenges and research gaps that require further exploration

MoVES: A Model-Driven Methodology for Vehicular Embedded Systems

This paper introduces a novel model-driven methodology for the software development of real-time distributed vehicular embedded systems on single-and multi-core platforms. The proposed methodology discloses the opportunity of improving the cost-efficiency of the development process by providing automated support to identify viable design solutions with respect to selected non-functional requirements. To this end, it leverages the interplay of modeling languages for the vehicular domain whose integration is achieved by a suite of model transformations. An instantiation of the methodology is discussed for timing requirements, which are among the most critical ones for vehicular systems. To support the design of temporally correct systems, cooperation between EAST-ADL and the Rubus component model is opportunely built-up by means of model transformations, enabling timing-aware design and model-based timing analysis of the system. The applicability of the methodology is demonstrated as the proof of concepts on industrial use cases performed in cooperation with our industrial partners

Annual Research Report, 2009-2010

Annual report of collaborative research projects of Old Dominion University faculty and students in partnership with business, industry and governmenthttps://digitalcommons.odu.edu/or_researchreports/1001/thumbnail.jp

Towards automated conceptual design space exploration

In\ua0mature and safety-concerned industries, such as the aerospace industry, product development is often incremental and design solutions are limited to improvements of an existing design. Radical changes to the known product architecture are avoided, for reasons of reliability, lack of technology or lack of design space exploration (DSE) methods. This thesis aims to investigate into the challenges for DSE, and how it can be improved to be faster, wider and more systematic. This research has been undertaken in four different research projects, addressing the challenges of the aerospace industry. The process of exploring the design space, the set of all possible designs, can be divided into three phases: to define the design space boundaries, to populate this design space with concepts, and lastly, to analyse the different concepts to find the one which provides the highest value. A deficiency in the description of functions and constraints which constitute the design space dimensions and boundaries, rooted in the lack of methods, has been identified to reduce the available search space already in the beginning. To populate this search space, developers need to generate representations of their new designs. These representations, commonly 3D geometries in the form of CAD models, are too rigid in the form they are used today. Therefore, it is expensive to create many variants, which differ in solutions and shape. This reduces the design space population to only a few concepts, derived from the legacy design. The analysis of alternative concepts is challenged through different maturities and variety of concepts.The coverage of multiple hierarchical search spaces, from geometry over solutions to value, has been identified as a driver for wider DSE. Furthermore, the need for a product development approach that is capable to bridge the levels of modelling abstraction. Enhanced Function-Means (EF-M) modelling, a function model applied in all studies referenced in this thesis, bridges the abstraction from a verbal description to a teleological graph, while enabling a more systematic capture of the design space boundaries. However, a subsequent gap towards geometry models could be observed in all studies. This hindered a faster design space exploration, since extensive manual labour is required to bridge these abstraction levels. For further work, the closing of the abstraction gap in the product modelling methods is seen as the primary goal for further work, either by extending the already applied function- and geometry modelling methods, or by including other frameworks