Composition and Correctness

AbstractThis paper presents an approach to ensure correctness of composed systems. It takes into consideration that correctness can usually be achieved only to a certain degree (except for some small and very mission-critical applications) and complete specifications are usually not practicable. By modelling the parts, the composition activities and the requirements specification we automise the checking procedures using model checking. An important issue hereby is that our approach allows partial modelling and specification

High-Dimensional Spatio-Temporal Indexing

There exist numerous indexing methods which handle either spatio-temporal or high-dimensional data well. However, those indexing methods which handle spatio-temporal data well have certain drawbacks when confronted with high-dimensional data. As the most efficient spatio-temporal indexing methods are based on the R-tree and its variants, they face the well known problems in high-dimensional space. Furthermore, most high-dimensional indexing methods try to reduce the number of dimensions in the data being indexed and compress the information given by all dimensions into few dimensions but are not able to store now - relative data. One of the most efficient high-dimensional indexing methods, the Pyramid Technique, is able to handle high-dimensional point-data only. Nonetheless, we take this technique and extend it such that it is able to handle spatio-temporal data as well. We introduce a technique for querying in this structure with spatio-temporal queries. We compare our technique, the Spatio-Temporal Pyramid Adapter (STPA), to the RST-tree for in-memory and on-disk applications. We show that for high dimensions, the extra query-cost for reducing the dimensionality in the Pyramid Technique is clearly exceeded by the rising query-cost in the RST-tree. Concluding, we address the main drawbacks and advantages of our technique

High-dimensional spatio-temporal indexing

There exist numerous indexing methods which handle either spatio-temporal or high-dimensional data well. How- ever, those indexing methods which handle spatio-temporal data well have certain drawbacks when confronted with high-dimensional data. As the most efficient spatio-temporal indexing methods are based on the R-tree and its variants, they face the well known problems in high-dimensional space. Furthermore, most high-dimensional indexing methods try to reduce the number of dimensions in the data being indexed and compress the information given by all dimensions into few dimensions but are not able to store now - relative data. One of the most efficient high-dimensional indexing methods, the Pyramid Technique, is able to handle high-dimensional point-data only. Nonetheless, we take this technique and extend it such that it is able to handle spatio-temporal data as well. We introduce a technique for querying in this structure with spatio-temporal queries. We compare our technique, the Spatio-Temporal Pyramid Adapter (STPA), to the RST-tree for in-memory and on-disk applications. We show that for high dimensions, the extra query-cost for reducing the dimensionality in the Pyramid Technique is clearly ex- ceeded by the rising query-cost in the RST-tree. Concluding, we address the main drawbacks and advantages of our technique

Automatic Code Generation of Safety Mechanisms in Model-Driven Development

In order to meet regulatory standards in the domain of safety-critical systems, these systems have to include a set of safety mechanisms depending on the Safety Integrity Level (SIL). This article proposes an approach for how such safety mechanisms may be generated automatically via Model-Driven Development (MDD), thereby improving developer productivity and decreasing the number of bugs that occur during manual implementation. The approach provides a structured way to define safety requirements, which may be parsed automatically and are used for the generation of software-implemented safety mechanisms, as well as the initial configuration of hardware-implemented safety mechanisms. The approach for software-implemented safety mechanisms relies on the Unified Modeling Language (UML) for representing these mechanisms in the model and uses model transformations to realize them in an intermediate model, from which code may be generated with simple 1:1 mappings. The approach for hardware-implemented safety mechanisms builds upon a template-based code snippet repository and a graphical user interface for configuration. The approach is applied to the development of a safety-critical fire detection application and the runtime of the model transformations is evaluated, indicating a linear scalability of the transformation steps. Furthermore, we evaluate the runtime and memory overhead of the generated code

Reusability of Concerns

Various recent approaches aim at improving the application of the separation of concerns principle by introducing new system units. Although they seem to have the potential to improve the system development process, additional challenges evolve. This paper addresses some challenges concerning the reusability of these new system units. Our considerations about reusability are twofold. First, the independence of these system units is regarded on the mechanism level. Second, the composition validation problem emerging from the composition of these new and also reusable system units is investigated. The problems are illustrated by means of two examples. 1 Introduction and Problem Classification Common to recent approaches exploring the future beyond "objects" is that they all aim at a better separation of concerns. Besides objects, they introduce new units encapsulating concerns along additional dimensions. In this paper we comprise these units in the term "units of concerns". Though th..

Robust Communication for Agricultural Process Management in Rural Areas : How dynamic Combination and Configuration of Communication Technologies enables robust Data Transfers in Rural Areas

Management of agricultural processes is often troubled by disconnections and data transfer failures. Limited cellular network coverage may prevent information exchange between mobile process participants. The research projects KOMOBAR and ISOCom designed, implemented und field-tested a delay tolerant platform for robust communication in rural areas and challenging environments. An adaptable combination of infrastructure-based cellular networks and infrastructure-free multihop ad hoc communication (WLAN) leads to a variety of new communication opportunities. Temporal storage and forwarding of data on mobile farm machinery as well as dynamic platform configurations during process runtime strongly enhance reliability and robustness of data transfers

Hunting Energy Bugs in Embedded Systems: A Software-Model-In-The-Loop Approach

Power consumption has become a major design constraint, especially for battery-powered embedded systems. However, the impact of software applications is typically considered in later phases, where both software and hardware parts are close to their finalization. Power-related issues must be detected in early stages to keep the development costs low, satisfy time-to-market, and avoid cost-intensive redesign loops. Moreover, the variety of hardware components, architectures, and communication interfaces make the development of embedded software more challenging. To manage the complexity of software applications, approaches such as model-driven development (MDD) may be used. This article proposes a power-estimation approach in MDD for software application models in early development phases. A unified modeling language (UML) profile is introduced to model power-related properties of hardware components. To determine the impact of software applications, we defined two analysis methods using simulation data and a novel in-the-loop concept. Both methods may be applied at different development stages to determine an energy trace, describing the energy-related behavior of the system. A novel definition of energy bugs is provided to describe power-related misbehavior. We apply our approach to a sensor node example, demonstrate an energy bug detection, and compare the runtime and accuracy of the analysis methods