Mikael Åkerholm

Evaluation of component technologies with respect to industrial requirements

We compare existing component technologies for embedded systems with respect to industrial requirements. The requirements are collected from the vehicular industry, but our findings are applicable to similar industries developing resource constrained safety critical embedded distributed real-time computer systems. One of our conclusions is that none of the studied technologies is a perfect match for the industrial requirements. Furthermore, no single technology stands out as being a significantly better choice than the others; each technology has its own pros and cons. The results of our evaluation can be used to guide modifications or extensions to existing technologies, making them better suited for industrial deployment. Companies that want to make use of component-based software engineering as available today can use this evaluation to select a suitable technology.

Introducing a Component Technology for Safety Critical Embedded Real-Time Systems

Safety critical embedded real-time systems represent a class of systems that has attracted relatively little attention in research addressing component based software engineering. Hence, the most widely spread component technologies are not used for resource constrained safety critical real-time systems. They are simply to resource demanding, to complex and to unpredictable. In this paper we show how to use component based software engineering for low footprint systems with very high demands on safe and reliable behaviour. The key concept is to provide expressive design time models and yet resource effective run-time models by statically resolve resource usage and timing by powerful compile time techniques. This results in a component technology for resource effective and temporally verified mapping of a component model to a commercial real-time operating system.

Optimizing resource usage in component-based real-time systems

The embedded systems domain represents a class of systems that have high requirements on cost efficiency as well as run-time properties such as timeliness and dependability. The research on component-based systems has produced component technologies for guaranteeing real-time properties. However, the issue of saving resources by allocating several components to real-time tasks has gained little focus. Trade-offs when allocating components to tasks are, e.g., CPU-overhead, footprint and integrity. In this paper we present a general approach for allocating components to real-time tasks, while utilizing existing real-time analysis to ensure a feasible allocation. We demonstrate that CPU-overhead and memory consumption can be reduced by as much as 48% and 32% respectively for industrially representative systems.

Towards a dependable component technology for embedded system applications

Component-based software engineering is a technique that has proven effective to increase reusability and efficiency in development of office and Web applications. Though being promising also for development of embedded and dependable systems, the true potential in this domain has not yet been realized. In this paper, we present a prototype component technology developed with safety-critical automotive applications in mind. The technology is illustrated by a case-study, which is also used as the basis for an evaluation and a discussion of the appropriateness and applicability in the considered domain. Our study provides initial positive evidence of the suitability of our technology, but also shows that it needs to be extended to be fully applicable in an industrial context.

A Model for Reuse and Optimization of Embedded Software Components

In software engineering for embedded systems generic reusable software components must often be discarded in favor of using resource optimized solutions. In this paper we outline a model that enables the utilization of component-based principles even for embedded systems with high optimization demands. The model supports the creation of component variants optimized for different scenarios, through the introduction of an entrance preparation step and an ending verification step into the component design process. These activities are proposed to be supported by tools working on metadata associated with components, where the metadata is possible to automatically retrieve from many development tools. This paper outlines the theoretical model that is the basis for our current realization work.

Application of built-in-testing in component-based embedded systems

This work-in-progress paper discusses challenges with application of Built-In Testing (BIT) in component-based embedded-systems. Testing constitutes a large part of the time and budget in development of embedded software systems. Such systems are often mission-critical, making testing highly important, and at the same time testing embedded systems is challenging because of their limited observability. We investigate the possible application of BIT in components for embedded systems, as a technique to advance the technology and knowledge for analysis and verification of functional correctness, real-time behavior, safety, and reliability of these systems.

Key factors for achieving project success in integration of automotive mechatronics

In this paper, we present a multiple case study on integration of automotive mechatronic components. Based on the findings, we identify that the root causes of problems in integration are largely related to decisions omitted in electronic strategy. We present and recommend use of checklists defining key factors to address in order to achieve successful integration projects in terms of cost and quality. Our recommendations are defined by checklists for critical decisions in areas: functionality, platform, integration, and stakeholder involvement. The recommendations are established based on practitioner experience and then validated in a multiple case study. Five cases of integration are studied for different heavy vehicles in one company, and the fulfillment of our recommendations is measured. Finally we define project success criteria and we compare the level of fulfillment with the project success in terms of time plan and resource consumption. The main contribution of this study is the validated recommendations, each including a set of checkpoints that defines recommendation fulfillment. We also present defining characteristics to identify a high-risk project. We provide a set of observable project properties and show how they affect project risk.

Efficient software component reuse in safety-critical systems --- an empirical study

The development of software components to be reused in safety-critical systems involves a number of challenges. These are related to both the goals of using the component in several systems, with different definitions of system-specific hazards, and on the high demands of todays safety standards, which assume a top-down system and software development process. A large part of the safety-related activities is therefore left for integrator, and there is a risk that a pre-existing component will neither be feasible nor more efficient to use than internal development of the same functionality. In this paper we address five important challenges, based on an empirical study consisting of interviews with experts in the field, and a case study. The result is twelve concrete practices found to improve the overall efficiency of such component development, and their subsequent reuse. These are related to the component architecture and configuration interface, component and system testing and verification, and the information to be provided with the component.

Introducing Component Based Software Engineering at an Embedded Systems Sub-Contractor

Attractive benefits with successful implementation of component-based principles include managing complexity, reduction of time-to-market, increased quality, and reusability. Deployment of component-based development is however not simple - it depends on many strategic, technical, and business decisions. In this paper we report experiences from our attempts with finding a correct implementation of component-based principles for the business situation of sub-contractors of embedded systems. Findings related to suitable component models, component technologies, and component management are presented. Overall the results confirm the suitability of component-based principles for the domain, but also show the need (and potential) in further development of CBSE theory and technology for embedded systems.

An Event Algebra Extension of the Triggering Mechanism in a Component Model for Embedded Systems

In this article we present how the component triggering in SaveCCM, a component model intended for embedded vehicular systems, can be extended by means of an event algebra. The extension allows components to be triggered by complex event patterns, and not only by clock signals or single external events. Separating the detection of triggering conditions from the definition of the triggered services permits more general components and thus improves component reusability. Providing event detection mechanisms within the component model means that triggering conditions are explicitly available for system analysis at design time. An event algebra is used to define the complex triggering conditions. This algebra has a relatively simple declarative semantics and well documented algebraic properties, which facilitates formal and informal reasoning about the system. The algebra also ensures that detection of triggering conditions can be efficiently implemented with limited resources, which is critical in embedded applications.