Generating Complete and Finite Test Suite for ioco: Is It Possible?

Testing from Input/Output Transition Systems has been intensely investigated. The conformance between the implementation and the specification is often determined by the so-called ioco-relation. However, generating tests for ioco is usually hindered by the problem of conflicts between inputs and outputs. Moreover, the generation is mainly based on nondeterministic methods, which may deliver complete test suites but require an unbounded number of executions. In this paper, we investigate whether it is possible to construct a finite test suite which is complete in a predefined fault domain for the classical ioco relation even in the presence of input/output conflicts. We demonstrate that it is possible under certain assumptions about the specification and implementation, by proposing a method for complete test generation, based on a traditional method developed for FSM.Comment: In Proceedings MBT 2014, arXiv:1403.704

A comprehensive approach in performance evaluation for modernreal-time operating systems

In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.Publicad

"Pricing the major hub airports"

Implementing congestion pricing at twenty-seven major US airports would reduce delays by thirteen passenger-years and one thousand aircraft-hours every day, saving three to five million dollars. Chicago and Atlanta would save about one thousand dollars per aircraft. Airport revenues would increase about eleven million dollars daily. A bottleneck model with stochastic queues estimates substantial welfare gains whether or not airlines internalize self-imposed delays. Erroneously imposing fees from the non-internalizing specification on internalizing airlines, however, would be a costly mistake. The model calculates equilibrium traffic rates, queuing delays, layover times, connection times, and congestion fee schedules by minute of the day.airport congestion pricing, stochastic queuing, bottleneck model.

The Grass Is Not Always Greener: A Look at National Health Care Systems Around the World

Critics of the U.S. health care system frequently point to other countries as models for reform. They point out that many countries spend far less on health care than the United States yet seem to enjoy better health outcomes. The United States should follow the lead of those countries, the critics say, and adopt a government- run, national health care system. However, a closer look shows that nearly all health care systems worldwide are wrestling with problems of rising costs and lack of access to care. There is no single international model for national health care, of course. Countries vary dramatically in the degree of central control, regulation, and cost sharing they impose, and in the role of private insurance. Still, overall trends from national health care systems around the world suggest the following: Health insurance does not mean universal access to health care. In practice, many countries promise universal coverage but ration care or have long waiting lists for treatment. Rising health care costs are not a uniquely American phenomenon. Although other countries spend considerably less than the United States on health care, both as a percentage of GDP and per capita, costs are rising almost everywhere, leading to budget deficits, tax increases, and benefit reductions. In countries weighted heavily toward government control, people are most likely to face waiting lists, rationing, restrictions on physician choice, and other obstacles to care. Countries with more effective national health care systems are successful to the degree that they incorporate market mechanisms such as competition, cost sharing, market prices, and consumer choice, and eschew centralized government control. Although no country with a national health care system is contemplating abandoning universal coverage, the broad and growing trend is to move away from centralized government control and to introduce more market-oriented features. The answer then to America's health care problems lies not in heading down the road to national health care but in learning from the experiences of other countries, which demonstrate the failure of centralized command and control and the benefits of increasing consumer incentives and choice

10421 Abstracts Collection -- Model-Based Testing in Practice

From 17.10. to 22.10.2010, the Dagstuhl Seminar 10421 ``Model-Based Testing in Practice \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Simulation of Mixed Critical In-vehicular Networks

Future automotive applications ranging from advanced driver assistance to autonomous driving will largely increase demands on in-vehicular networks. Data flows of high bandwidth or low latency requirements, but in particular many additional communication relations will introduce a new level of complexity to the in-car communication system. It is expected that future communication backbones which interconnect sensors and actuators with ECU in cars will be built on Ethernet technologies. However, signalling from different application domains demands for network services of tailored attributes, including real-time transmission protocols as defined in the TSN Ethernet extensions. These QoS constraints will increase network complexity even further. Event-based simulation is a key technology to master the challenges of an in-car network design. This chapter introduces the domain-specific aspects and simulation models for in-vehicular networks and presents an overview of the car-centric network design process. Starting from a domain specific description language, we cover the corresponding simulation models with their workflows and apply our approach to a related case study for an in-car network of a premium car

The complexity of asynchronous model based testing

This is the post-print version of the final paper published in Theoretical Computer Science. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.In model based testing (MBT), testing is based on a model MM that typically is expressed using a state-based language such as an input output transition system (IOTS). Most approaches to MBT assume that communications between the system under test (SUT) and its environment are synchronous. However, many systems interact with their environment through asynchronous channels and the presence of such channels changes the nature of testing. In this paper we investigate the situation in which the SUT interacts with its environment through asynchronous channels and the problems of producing test cases to reach a state, execute a transition, or to distinguish two states. In addition, we investigate the Oracle Problem. All four problems are explored for both FIFO and non-FIFO channels. It is known that the Oracle Problem can be solved in polynomial time for FIFO channels but we also show that the three test case generation problems can also be solved in polynomial time in the case where the IOTS is observable but the general test generation problems are EXPTIME-hard. For non-FIFO channels we prove that all of the test case generation problems are EXPTIME-hard and the Oracle Problem in NP-hard, even if we restrict attention to deterministic IOTSs

Discovering Job Preemptions in the Open Science Grid

The Open Science Grid(OSG) is a world-wide computing system which facilitates distributed computing for scientific research. It can distribute a computationally intensive job to geo-distributed clusters and process job's tasks in parallel. For compute clusters on the OSG, physical resources may be shared between OSG and cluster's local user-submitted jobs, with local jobs preempting OSG-based ones. As a result, job preemptions occur frequently in OSG, sometimes significantly delaying job completion time. We have collected job data from OSG over a period of more than 80 days. We present an analysis of the data, characterizing the preemption patterns and different types of jobs. Based on observations, we have grouped OSG jobs into 5 categories and analyze the runtime statistics for each category. we further choose different statistical distributions to estimate probability density function of job runtime for different classes.Comment: 8 page