13,846 research outputs found
A WSDL-Based Type System for WS-BPEL
We tackle the problem of providing rigorous formal foundations to current software engineering technologies for web services. We focus on two of the most used XML-based languages for web services: WSDL and WS-BPEL. To this aim, first we select an expressive subset of WS-BPEL, with special concern for modeling the interactions among web service instances in a network context, and define its operational semantics. We call ws-calculus the resulting formalism. Then, we put forward a rigorous typing discipline that formalizes the relationship existing between ws-calculus terms and the associated WSDL documents and supports verification of their compliance. We prove that the type system and the operational semantics of ws-calculus are âsoundâ and apply our approach to an example application involving three interacting web services
On data skewness, stragglers, and MapReduce progress indicators
We tackle the problem of predicting the performance of MapReduce
applications, designing accurate progress indicators that keep programmers
informed on the percentage of completed computation time during the execution
of a job. Through extensive experiments, we show that state-of-the-art progress
indicators (including the one provided by Hadoop) can be seriously harmed by
data skewness, load unbalancing, and straggling tasks. This is mainly due to
their implicit assumption that the running time depends linearly on the input
size. We thus design a novel profile-guided progress indicator, called
NearestFit, that operates without the linear hypothesis assumption and exploits
a careful combination of nearest neighbor regression and statistical curve
fitting techniques. Our theoretical progress model requires fine-grained
profile data, that can be very difficult to manage in practice. To overcome
this issue, we resort to computing accurate approximations for some of the
quantities used in our model through space- and time-efficient data streaming
algorithms. We implemented NearestFit on top of Hadoop 2.6.0. An extensive
empirical assessment over the Amazon EC2 platform on a variety of real-world
benchmarks shows that NearestFit is practical w.r.t. space and time overheads
and that its accuracy is generally very good, even in scenarios where
competitors incur non-negligible errors and wide prediction fluctuations.
Overall, NearestFit significantly improves the current state-of-art on progress
analysis for MapReduce
Data integration through service-based mediation for web-enabled information systems
The Web and its underlying platform technologies have often been used to integrate existing software and information systems. Traditional techniques for data representation and transformations between documents are not sufficient to support a flexible and maintainable data integration solution that meets the requirements of modern complex Web-enabled software and information systems. The difficulty
arises from the high degree of complexity of data structures, for example in business and technology applications, and from the constant change of data and its
representation. In the Web context, where the Web platform is used to integrate different organisations or software systems, additionally the problem of heterogeneity
arises. We introduce a specific data integration solution for Web applications such as Web-enabled information systems. Our contribution is an integration technology
framework for Web-enabled information systems comprising, firstly, a data integration technique based on the declarative specification of transformation rules and the construction of connectors that handle the integration and, secondly, a mediator architecture based on information services and the constructed connectors to handle the integration process
A Penny a Function: Towards Cost Transparent Cloud Programming
Understanding and managing monetary cost factors is crucial when developing
cloud applications. However, the diverse range of factors influencing costs for
computation, storage, and networking in cloud applications poses a challenge
for developers who want to manage and minimize costs proactively. Existing
tools for understanding cost factors are often detached from source code,
causing opaqueness regarding the origin of costs. Moreover, existing cost
models for cloud applications focus on specific factors such as compute
resources and necessitate manual effort to create the models. This paper
presents initial work toward a cost model based on a directed graph that allows
deriving monetary cost estimations directly from code using static analysis.
Leveraging the cost model, we explore visualizations embedded in a code editor
that display costs close to the code causing them. This makes cost exploration
an integrated part of the developer experience, thereby removing the overhead
of external tooling for cost estimation of cloud applications at development
time.Comment: Proceedings of the 2nd ACM SIGPLAN International Workshop on
Programming Abstractions and Interactive Notations, Tools, and Environments
(PAINT 2023), 10 pages, 5 figure
- âŠ