Most of the evolution in ambient assisted living is due to embedded
systems that dynamically adapt themself to react to environmental
changes or component/subsystem failures to maintain a certain level of
safety. Following this evolution fault tree analysis techniques have been
extended with concept for dynamic adaptation but resulting techniques
such as dynamic fault trees or state event fault trees analysis are not
widely used as expected.
In this report we describe a controlled experiment to analyze these two
techniques with regard to their applicability and efficiency in modeling
dynamic behavior of ambient assisted living systems.
Results of the experiment show that Dynamic Fault Trees are easier and more effective
to use, although they produce better results (models) with State Events Fault Trees.
Most innovation in the automotive industry is driven by embedded systems. They make usage of dynamic adaption to environmental changes or component/subsystem failures for remaining safe. Following this evolution, fault tree analysis techniques have been extended with concept for dynamic adaptation but resulting techniques like state event fault tree analysis, are not widely used in practice.
In this report we present the results of a controlled experiment that analyze these two techniques (State Events Fault Trees and Faul trees combined with markov chains) with regard to their applicability and efficiency in modeling dynamic behavior of dynamic embedded systems.
The experiment was conducted with students of the TU Kaiserslautern to modeli different safety aspects of an ambient assisted living system.
The main results of the experiment show that SEFTs where more easy and effective to use.
Conditional Compilation (CC) is frequently used as a variation mechanism in software product lines (SPLs). However, as a SPL evolves the variable code realized by CC erodes in the sense that it becomes overly complex and difficult to understand and maintain. As a result, the SPL productivity goes down and puts expected advantages more and more at risk. To investigate the variability erosion and keep the productivity above a sufficiently good level, in this paper we 1) investigate several erosion symptoms in an industrial SPL; 2) present a variability improvement process that includes two major improvement strategies. While one strategy is to optimize variable code within the scope of CC, the other strategy is to transition CC to a new variation mechanism called Parameterized Inclusion. Both of these two improvement strategies can be conducted automatically, and the result of CC optimization is provided. Related issues such as applicability and cost of the improvement are also discussed.
As a Software Product Line (SPL) evolves with increasing number of features and feature values, the feature correlations become extremely intricate, and the specifications of these correlations tend to be either incomplete or inconsistent with their realizations, causing misconfigurations in practice. In order to guide product configuration processes, we present a solution framework to recover complex feature correlations from existing product configurations. These correlations are further pruned automatically and validated by domain experts. During implementation, we use association mining techniques to automatically extract strong association rules as potential feature correlations. This approach is evaluated using a large-scale industrial SPL in the embedded system domain, and finally we identify a large number of complex feature correlations.
A translation contract is a binary predicate corrTransl(S,T) for source programs S and target programs T. It precisely specifies when T is considered to be a correct translation of S. A certifying compiler generates --in addittion to the target T-- a proof for corrTransl(S,T). Certifying compilers are important for the development of safety critical systems to establish the behavioral equivalence of high-level programs with their compiled assembler code. In this paper, we report on a certifying compiler, its proof techniques, and the underlying formal framework developed within the proof assistent Isabelle/HOL. The compiler uses a tiny C-like language as input, has an optimization phase, and generates MIPS code. The underlying translation contract is based on a trace semantics. We investigate design alternatives and discuss our experiences.
This paper deals with the handling of deformable linear objects (DLOs), such as hoses, wires, or leaf springs. It investigates usable features for the vision-based detection of a changing contact situation between a DLO and a rigid polyhedral obstacle and a classification of such contact state transitions. The result is a complete classification of contact state transitions and of the most significant features for each class. This knowledge enables reliable detection of changes in the DLO contact situation, facilitating implementation of sensor-based manipulation skills for all possible contact changes.
This paper describes motion primitives which solve some common recurrent problems encountered when manipulating deformable linear objects. As one example for the usefulness of these manipulations skills, the mounting of a leaf spring is presented here.
Die Domäne der Operationsroboter liegt heute in Fräsarbeiten an knöchernen Strukturen. Da Roboter über eine extreme Präzision verfügen und nicht ermüden bietet sich ihr Einsatz ins-besondere bei langwierigen und zugleich hochpräzisen Fräsvorgängen im Bereich der later-alen Schädelbasis an. Aus diesem Grunde wurde ein Verfahren entwickelt, welches aus einer geometrischen Beschreibung des Implantates eine geeignete Fräsbahn errechnet und eine kraftgeregelte Prozesskontrolle des Fräsvorganges implementiert. Mit einem 6*achsigen Knickarmroboter erfolgten die Untersuchungen primär an Tierpräparaten und zur Optimierung an Felsenbeinpräparaten.
While handling deformable linear objects (DLOs), such as hoses, wires or leaf springs, with an industrial robot at high speed, unintended and undesired oscillations that delay further operations may occur. This paper analyzes oscillations based on a simple model with one degree of freedom (DOF) and presents a method for active open-loop damping. Different ways to interpret an oscillating DLO as a system with 1 DOF lead to translational and rotational adjustment motions. Both were implemented as a manipulation skill with a sepa-rate program that can be executed immediately after any robot motion. We showed how these manipulation skills can generate the needed adjustment motions automatically based on the readings of a wrist-mounted force/torque sensor. Experiments demonstrated the effectiveness under various conditions.
Diese Arbeit beschreibt verschiedene Bewegungsprimitive zur Lösung einiger häufig auftre-tender Probleme bei der Handhabung von deformierbaren linearen Objekten. Anhand der beispielhaften Montage einer Feder wird die Nützlichkeit der verschiedenen Manipulation-Skills im einzelnen, aber auch deren Kombination dargestellt.
Empirical Evaluation of State Event Fault Tree and Dynamic Fault Tree for the Safety Analysis of Ambient Assisted Living
(2013)
