Creating telecommunication services based on object-oriented frameworks and SDL

This paper describes the tools and techniques being applied in the TINA Open Service Creation Architecture (TOSCA) project to develop object-oriented models of distributed telecommunication services in SDL. The paper also describes the way in which Tree and Tabular Combined Notation (TTCN) test cases are derived from these models and subsequently executed against the CORBA-based implementations of these services through a TTCN/CORBA gateway

Do System Test Cases Grow Old?

Companies increasingly use either manual or automated system testing to ensure the quality of their software products. As a system evolves and is extended with new features the test suite also typically grows as new test cases are added. To ensure software quality throughout this process the test suite is continously executed, often on a daily basis. It seems likely that newly added tests would be more likely to fail than older tests but this has not been investigated in any detail on large-scale, industrial software systems. Also it is not clear which methods should be used to conduct such an analysis. This paper proposes three main concepts that can be used to investigate aging effects in the use and failure behavior of system test cases: test case activation curves, test case hazard curves, and test case half-life. To evaluate these concepts and the type of analysis they enable we apply them on an industrial software system containing more than one million lines of code. The data sets comes from a total of 1,620 system test cases executed a total of more than half a million times over a time period of two and a half years. For the investigated system we find that system test cases stay active as they age but really do grow old; they go through an infant mortality phase with higher failure rates which then decline over time. The test case half-life is between 5 to 12 months for the two studied data sets.Comment: Updated with nicer figs without border around the

Experiences modelling and using object-oriented telecommunication service frameworks in SDL

This paper describes experiences in using SDL and its associated tools to create telecommunication services by producing and specialising object-oriented frameworks. The chosen approach recognises the need for the rapid creation of validated telecommunication services. It introduces two stages to service creation. Firstly a software expert produces a service framework, and secondly a telecommunications ‘business consultant' specialises the framework by means of graphical tools to rapidly produce services. Here the focus is given to the underlying technology required. In particular, the advantages and disadvantages of SDL and tools for this purpose are highlighted

Stateful Testing: Finding More Errors in Code and Contracts

Automated random testing has shown to be an effective approach to finding faults but still faces a major unsolved issue: how to generate test inputs diverse enough to find many faults and find them quickly. Stateful testing, the automated testing technique introduced in this article, generates new test cases that improve an existing test suite. The generated test cases are designed to violate the dynamically inferred contracts (invariants) characterizing the existing test suite. As a consequence, they are in a good position to detect new errors, and also to improve the accuracy of the inferred contracts by discovering those that are unsound. Experiments on 13 data structure classes totalling over 28,000 lines of code demonstrate the effectiveness of stateful testing in improving over the results of long sessions of random testing: stateful testing found 68.4% new errors and improved the accuracy of automatically inferred contracts to over 99%, with just a 7% time overhead.Comment: 11 pages, 3 figure

Towards the Usage of MBT at ETSI

In 2012 the Specialists Task Force (STF) 442 appointed by the European Telcommunication Standards Institute (ETSI) explored the possibilities of using Model Based Testing (MBT) for test development in standardization. STF 442 performed two case studies and developed an MBT-methodology for ETSI. The case studies were based on the ETSI-standards GeoNetworking protocol (ETSI TS 102 636) and the Diameter-based Rx protocol (ETSI TS 129 214). Models have been developed for parts of both standards and four different MBT-tools have been employed for generating test cases from the models. The case studies were successful in the sense that all the tools were able to produce the test suites having the same test adequacy as the corresponding manually developed conformance test suites. The MBT-methodology developed by STF 442 is based on the experiences with the case studies. It focusses on integrating MBT into the sophisticated standardization process at ETSI. This paper summarizes the results of the STF 442 work.Comment: In Proceedings MBT 2013, arXiv:1303.037

Enriching accounts of computer‐supported collaboration by using video data

This paper will discuss the approach to the evaluation of computer‐supported collaborative learning developed in our group over the past ten years. This approach depends on the collection of video data to allow the analysis of key features of problem‐solving behaviour within groups of students working on collaborative learning tasks. Our theoretical framework derives from two sources‐ the CIAOl framework for evaluating examples of CAL and an analysis of appropriate methods of evaluating computer‐supported collaboration. Our work in this area has been supported by developing the data capture facilities for the CALRG (Computers and Learning Research Group) at the Open University. We will draw on a number of studies to illustrate this approach and will present a brief case study from work done on a computer‐supported learning environment for statistics where we use video records of video‐mediated collaboration. This case study gives an example of the rich data that can be collected using video recording and analysed to increase understanding of computer‐supported collaboration

Teen Risk-Taking: Promising Prevention Programs and Approaches

To help close the knowledge gap and to help program directors, practitioners, and community leaders enlarge the network of effective programs and approaches for at-risk youth, Urban Institute researchers reviewed what is known about successful prevention interventions and their dissemination. They identified 51 problem behavior prevention interventions whose initial effectiveness has been demonstrated through scientific evaluation. A subset of 21 programs was selected on the basis of the rigor of their evaluations or the strength of their results for closer examination of the program elements and/or delivery modes that appeared to be associated with their effectiveness. The researchers also explored with the assistance of experienced prevention scientists and school-based practitioners what might be the essential elements of schools' and other community organizations' readiness to undertake research-based problem behavior prevention programming. This guidebook to promising programs and approaches offers the fruits of that research. It is our hope that it will provide a helpful starting point for the development of a larger, more sustainable network of effective prevention programs and approaches for at-risk teens.In the booklet you will find:An Update on Adolescent Risk-Taking -- what is known about the level and characteristics of teen risk-taking today and why it is both necessary and an opportune time to improve and expand the network of effective prevention programs for at-risk preteens and teens.The Common Elements of Successful Prevention Programs, briefly summarized, along with an explanation of the criteria used to select the 51 programs profiled in this guidebook.Moving from Research to Practice -- a discussion of the challenges facing practitioners seeking to replicate promising intervention programs or approaches, with some suggestions for ways to meet these challenges.A Prevention Readiness Questionnaire to help program directors and planners identify and assess factors necessary to create favorable conditions and circumstances for successful adaptation or replication of the programs or their salient components in new settings.Profiles of 51 Prevention Programs whose behavioral evaluations demonstrate their effectiveness. The profiles provide general information about the program, highlight unique features, summarize evaluation results, and give general contact information. The 21 (most) rigorously evaluated programs also have curriculum, training, and contact information included.A Handy Reference Chart for quick comparison of the 51 programs