Feature cardinalities in feature diagrams determine the number of times a feature and its subtree can be duplicated during configuration by an operation named "cloning".Other authors already investigated the problem and published different proposals of semantics for this construct. However, this previous work is not easily amenable to the formal study of the various properties of feature diagrams and their derived configurations. Also, cross-tree constraint languages still need to be properly extended to account for feature cardinalities.This paper presents an extension of an earlier formal semantics of feature diagrams by adding support for feature cardinalities.
Strings are ubiquitous in software. Tools for specification,verification and test-case generation of software rely in various degrees onrepresenting and reasoning about strings. Reasoning about strings isparticularly important in several security critical applications, such asweb sanitizers. Besides a basic representation of strings, applicationsalso use string recognizers and transducers.This paper presents a proposal for an SMT-LIBization of strings and regularexpressions. It introduces a theory of sequences, generalizing strings,and builds a theory of regular experssions on top of sequences.The logic QF_BVRE is designed to capture a common substrate amongexisting tools for string constraint solving.
The evaluation of new reagents and instruments in clinical chemistry leads to complex studies with large volumes of data, which are difficult to handle. This paper presents the design and development of a program that supports an evaluator in the definition of a study, the generation of data structures, communication with the instrument (analyser), online and offline data capture and in the processing of the results. The program is called CAEv, and it runs on a standard PC under MS-DOS. Version 1 of the program was tested in a multicentre instrument evaluation. The concept and the necessary hardware and software are discussed. In addition, requirements for instrument/host communication are given. The application of the laboratory part of CAEv is described from the user's point of view. The design of the program allows users a high degree of flexibility in defining their own standards with regard to study protocol, and/or experiments, without loss of performance. CAEv's main advantages are a pre-programmed study protocol, easy handling of large volumes of data, an immediate validation of the experimental results and the statistical evaluation of the data.
In this paper, we explore a novel application domain for SMT solvers: configuration problems. Configuration problems are everywhere and particularly in product lines, where different yet similar products (e.g., cars or customizable software) are built from a shared set of assets. Designing a product line requires enumerating the different product features and the constraints that determine their valid combinations. Various categories of constraint solvers exist, but SMT solvers appear to be a solution of choice for configuration problems. This is mostly due to their high efficiency and expressiveness which have already proved useful in a variety of practical applications. In this paper, we recall what configuration problems are, describe a language to represent them, and map from configuration problems to the satisfiability problem over SMT theories. Variability Modelling and Configuration ProblemProduct lines have become an integral part of modern industry, be it in the manufacturing, the service or the software sectors [20]. Many kinds of products such as cars, insurance contracts or operating systems are developed as assemblies and customizations of reusable components, called configurations. Some configurations are valid, some are not, depending on numerous constraints including physical, mechanical, business, legal and design constraints. Moreover, manufacturers have an economic incentive, often dubbed with a legal obligation, in making sure that every possible configuration will result in a viable, safe, secure and useable product. Languages exist in which configuration problems can be encoded. These are often called variability modeling languages. Software tools have been built to automate all sorts of reasoning on variability models so as to uncover errors and inconsistencies [2].Cars are probably the most well-known example of a configurable product. Cars can be equipped with different types of engines, transmissions and gearboxes. Similarly, different bodyworks (sedan, break, sport, cabriolet, etc.), paints, wheel types, and dozens of other options are available for most recent models. When designing a new car model, the manufacturer has to establish a list the various possible options and all the applicable configuration constraints. Some options are obviously incompatible (e.g. a cabriolet cannot have a moonroof), but dependencies among certain options can be subtle (e.g. an integrated GPS requires a color screen, which in turn requires a multifunction steering wheel).To build a car configurator similar to those found on the websites of car manufacturers, all these constraints need to be taken into account in order to guarantee that the final configuration will correspond to a car (1) that can actually be built and (2) that the manufacturer wishes to sell. When the variability model of a new car has been produced, the manufacturer can use it to verify properties of the products that can be derived, e.g., "Do all LPG cars also include a
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