A comparison of schedulability analysis methods using state and digraph models for the schedulability analysis of synchronous FSMs

Real-Time Systems - Synchronous reactive models are widely used in the development of embedded software and systems. The schedulability analysis of tasks obtained as the code implementation of...     

Reconfigurable natural interaction in smart environments: approach and prototype implementation

The vision of sensor-driven applications that adapt to the environment hold great promise, but it is difficult to turn these applications into reality because device and space heterogeneity is an obstacle to interoperability and mutual understanding of the smart devices and spaces involved. Smart Spaces provide shared knowledge about physical domains and they inherently enable cooperative and adaptable applications by keeping track of the semantic relations between objects in the environment. In this paper, the interplay between sensor-driven objects and Smart Spaces is investigated and a device with a tangible interface demonstrates the potential of the ${\sl smart{\text -}space{\text -}based}$ and ${\sl sensor{\text -}driven}$ computing paradigm. The proposed device is named REGALS (Reconfigurable Gesture based Actuator and Low Range Smartifier). We show how, starting from an interaction model proposed by Niezen, REGALS can reconfigure itself to support different functions like Smart Space creation (also called ${\sl environment\,smartification}$ ), interaction with heterogeneous devices and handling of semantic connections between gestures, actions, devices, and objects. This reconfiguration ability is based on the context received from the Smart Space. The paper also shows how tagged objects and natural gestures are recognized to improve the user experience reporting a use case and the performance evaluation of REGALS’ gesture classifier.     

Evaluating pattern conformance of UML models: a divide-and-conquer approach and case studies

A design pattern is realized in various forms depending on the context of the applications. There has been intensive research on detecting pattern instances in models and in implementations. However, little work addresses variations of pattern realization. This paper describes an approach for evaluating conformance of pattern variations. This approach uses a divide-and-conquer strategy to evaluate the structural conformance of a UML class diagram to the solution of a design pattern. A design pattern is specified in an extension of the UML that defines the pattern in terms of roles. To demonstrate the approach, we use the Visitor pattern and two case studies of a price calculator and a word processor. We also present a prototype tool that supports the approach.

A state-based approach to integration testing based on UML models

Correct functioning of object-oriented software depends upon the successful integration of classes. While individual classes may function correctly, several new faults can arise when these classes are integrated together. In this paper, we present a technique to enhance testing of interactions among modal classes. The technique combines UML collaboration diagrams and statecharts to automatically generate an intermediate test model, called SCOTEM (State COllaboration TEst Model). The SCOTEM is then used to generate valid test paths. We also define various coverage criteria to generate test paths from the SCOTEM model. In order to assess our technique, we have developed a tool and applied it to a case study to investigate its fault detection capability. The results show that the proposed technique effectively detects all the seeded integration faults when complying with the most demanding adequacy criterion and still achieves reasonably good results for less expensive adequacy criteria.     

From UML/OCL to SBVR specifications: A challenging transformation

UML is currently the most widely used modeling language for the specification of the conceptual schema (CS) of an information system (IS). However, UML falls short when it comes to allow business people to define in their own language (e.g. using their own terms in natural language) the policies and rules by which they run their business. To this purpose, the semantics of business vocabulary and business rules (SBVR) metamodel specification was proposed. SBVR is conceptualized optimally for business people and it is designed to be used for business purposes, independently of information systems designs.     

UML Distilled: From Difficulties to Assets

This month's Bookshelf features reviews of UML Distilled: A Brief Guide to the Standard Object Modeling Language, 3rd ed. by Martin Fowler, Testing Computer Software, 2nd ed. by Cem Kaner, Jack Falk, and Hung Quoc Nguyen, Test-Driven Development: By Example by Kent Beck, Lessons Learned in Software Testing by Cem Kaner, James Bach & Bret Pettichord, and Five Core Metrics: The Intelligence behind Successful Software Management by Lawrence H. Putnam and Ware Myers.     

Validation and automatic test generation on UML models: the AGATHA approach

The related economic goals of test generation are quite important for software industry. Manufacturers ever seeking to increase their productivity need to avoid malfunctions at the time of system specification: the later the defaults are detected, the greater the cost is. Consequently, the development of techniques and tools able to efficiently support engineers who are in charge of elaborating the specification constitutes a major challenge whose fallout concerns not only sectors of critical applications but also all those where poor conception could be extremely harmful to the brand image of a product.This article describes the design and implementation of a set of tools allowing software developers to validate UML (the Unified Modeling Language) specifications. This toolset belongs to the AGATHA environment, which is an automated test generator, developed at CEA/LIST.The AGATHA toolset is designed to validate specifications of communicating concurrent units described using an EIOLTS formalism (Extended Input Output Labeled Transition System). The goal of the work described in this paper is to provide an interface between UML and an EIOLTS formalism giving the possibility to use AGATHA on UML specifications.In this paper we describe first the translation of UML models into the EIOLTS formalism, and the translation of the results of the behavior analysis, provided by AGATHA, back into UML. Then we present the AGATHA toolset; we particularly focus on how AGATHA overcomes several problems of combinatorial explosion. We expose the concept of symbolic calculus and detection of redundant paths, which are the main principles of AGATHA's kernel. This kernel properly computes all the symbolic behaviors of a system specified in EIOLTS and automatically generates tests by way of constraint solving. Eventually we apply our method to an example and explain the different results that are computed.     

Validation and automatic test generation on UML models: the AGATHA approach

UML-based methodologies take more and more space in the software development domain. In addition, the need to validate applications as early as possible in the development cycle is now mandatory to satisfy cost and time-to-market constraints. In this context, this paper describes, first, how to bridge the gap between semiformal UML models and a formal technology ensuring test case generation. Second, the formal tool used to automatically generate test sequences, named AGATHA, is described in minute detail. Finally, this approach is illustrated throughout by a toy example of an elevator system.     

Applying black-box testing to UML/OCL database models

Most Unified Modeling Language (UML) computer-aided software engineering tools have been insufficient in the development process because they provide little support for conceptual model testing. Model testing aims to ensure the correctness of a UML/OCL class diagram, or, in other words, that a given class diagram can perfectly meet the user’s requirements. This study proposes the validation of class diagrams with black-box testing, a technique used to test software without focusing on the software’s implementation or structure. An approach is proposed for the automatic transformation of the constraints of a UML/OCL class diagram into test cases. Following the creation of the test cases, they are executed with JUnit and the results produced are shown to the tester. To demonstrate the applicability of this approach, an effectiveness evaluation and an efficiency evaluation are performed here. Evaluation studies show that all faults included in a class diagram have been detected within an efficient time.     

From fine-grained to abstract process models: A semantic approach

Organizations actively managing their business processes face a rapid growth of the number of process models that they maintain. Business process model abstraction has proven to be an effective means to generate readable, high-level views on business process models by showing coarse-grained activities and leaving out irrelevant details. In this way, abstraction facilitates a more efficient management of process models, as a single model can provide for many relevant views. Yet, it is an open question how to perform abstraction in the same skillful way as experienced modelers combine activities into more abstract tasks. This paper presents an approach that uses semantic information of a process model to decide on which activities belong together, which extends beyond existing approaches that merely exploit model structural characteristics. The contribution of this paper is twofold: we propose a novel activity aggregation method and suggest how to discover the activity aggregation habits of human modelers. In an experimental validation, we use an industrial process model repository to compare the developed activity aggregation method with actual modeling decisions, and observe a strong correlation between the two. The presented work is expected to contribute to the development of modeling support for the effective process model abstraction.     

Synthesis of simulation and implementation code for OpenMAX multimedia heterogeneous systems from UML/MARTE models

Multimedia Tools and Applications - The design of multimedia systems is becoming a more and more challenging task due to the combination of growing functionalities and strict performance...     

From requirements to UML models and back: how automatic processing of text can support requirements engineering

Software engineering is supposed to be a structured process, but manual tasks leave much leeway. Ideally, these tasks lie in the hands of skilled analysts and software engineers. This includes creating the textual specification of the envisioned system as well as creating models for the software engineers. Usually, there is quite a bit of erosion during the process due to requirement changes, implementation decisions, etc. To deliver the software as specified, textual requirements, models, and the actual software need to be synchronized. However, in practice, the cost of manually maintaining consistency is too high. Our requirements engineering feedback system automates the process of keeping textual specification and models consistent when the models change. To improve overall processing of natural language specifications, our approach finds flaws in natural language specifications. In addition to the already published workshop paper, we show how well our tools support even non-software-engineers in improving texts. The case studies show that we can speed up the process of creation texts with fewer flaws significantly.     

Myriad: Design and implementation of a federated database prototype

A key problem in providing ‘enterprise-wide’ information is the integration of databases that have been independently developed. An important requirement is to accommodate heterogeneity and maintain the autonomy of component databases. Myriad is a federated database prototype developed at the University of Minnesota, to provide a testbed for investigating alternatives in architecture and algorithms for database integration, query processing and optimization, and concurrency control and recovery. The system incorporates our group's research results in these areas. This paper describes our experiences in the design and implementation of Myriad, and in the project management. Special emphasis is given to discussing design alternatives and their impact on Myriad. This paper also presents the software engineering principles and the project management techniques we used in developing Myriad and the lessons we learned. We believe these lessons would be useful for practitioners who wish to develop a similar system. Handling heterogeneity and autonomy were prime objectives throughout the prototyping effort. We are convinced that a prototype federated database is an important infrastructural requirement for the overall goal of ‘enterprise-integration’, and believe Myriad to be a significant contribution towards this.     

Synthesizing test scenarios in UML activity diagram using a bio-inspired approach

The model-based analysis is receiving a wide acceptance as compare to code-based analysis in the context of prioritizing and guiding the testing effort and speeding up the development process. Ordinarily, system analysts as well as developers follow Unified Modeling Language (UML) activity diagrams to render all realizable flows of controls commonly recognized as scenarios of use cases. This paper applies a bio-inspired algorithm to produce test scenarios for the concurrent section in UML activity diagram. Here, the heuristic draws its inspiration from the internal mechanism of the slime mould Physarum Polycephalum, a large single-celled amoeboid organism. Simulations are performed using eight subject systems taken from the LINDHOLMEN data-set, two models taken from real life student projects and five synthetic models. The results obtained through different approaches are validated through the statistical analysis which demonstrates that our proposed approach is better than the existing Ant Colony Optimization (ACO) and Genetic Algorithm (GA) by a number of feasible test scenarios generated.     

OWL rules: A proposal and prototype implementation

Although the OWL Web Ontology Language adds considerable expressive power to the Semantic Web it does have expressive limitations, particularly with respect to what can be said about properties. We present the Semantic Web Rule Language (SWRL), a Horn clause rules extension to OWL that overcomes many of these limitations. SWRL extends OWL in a syntactically and semantically coherent manner: the basic syntax for SWRL rules is an extension of the abstract syntax for OWL DL and OWL Lite; SWRL rules are given formal meaning via an extension of the OWL DL model-theoretic semantics; SWRL rules are given an XML syntax based on the OWL XML presentation syntax; and a mapping from SWRL rules to RDF graphs is given based on the OWL RDF/XML exchange syntax. We discuss the expressive power of SWRL, showing that the ontology consistency problem is undecidable, provide several examples of SWRL usage, and discuss a prototype implementation of reasoning support for SWRL.     

An inferential approach to Information Retrieval and its implementation using a manual thesaurus

Most inferential approaches to Information Retrieval (IR) have been investigated within the probabilistic framework. Although these approaches allow one to cope with the underlying uncertainty of inference in IR, the strict formalism of probability theory often confines our use of knowledge to statistical knowledge alone (e.g. connections between terms based on their co-occurrences). Human-defined knowledge (e.g. manual thesauri) can only be incorporated with difficulty. In this paper, based on a general idea proposed by van Rijsbergen, we first develop an inferential approach within a fuzzy modal logic framework. Differing from previous approaches, the logical component is emphasized and considered as the pillar in our approach. In addition, the flexibility of a fuzzy modal logic framework offers the possibility of incorporating human-defined knowledge in the inference process. After defining the model, we describe a method to incorporate a human-defined thesaurus into inference by taking user relevance feedback into consideration. Experiments on the CACM corpus using a general thesaurus of English, Wordnet, indicate a significant improvement in the system's performance.