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Using formal methods to support testing
Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent
years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing
Vertical intra-industry trade and the EU accession: The case of Hungarian agri-food sector
The aim of this paper is to examine the relationship between the factor endowment and the
pattern of intra-industry trade. Our empirical analysis relates to Hungary’s intra-industry trade
in agri-food products with 26 member states of the EU over the period 1999-2010.
Estimations reject the comparative advantage explanation of vertical intra-industry trade and
provide partial support the prediction of Flam and Helpman model. Findings highlight that
nature of factor endowments play also important role in explanation of vertical intra-industry
trade. Other variables like market size and distance confirm the theoretical expectations. In
addition, trade with new member states positively, whilst the EU accession ambigouosly
influence the share of vertical IIT
Naming the Pain in Requirements Engineering: A Design for a Global Family of Surveys and First Results from Germany
For many years, we have observed industry struggling in defining a high
quality requirements engineering (RE) and researchers trying to understand
industrial expectations and problems. Although we are investigating the
discipline with a plethora of empirical studies, they still do not allow for
empirical generalisations. To lay an empirical and externally valid foundation
about the state of the practice in RE, we aim at a series of open and
reproducible surveys that allow us to steer future research in a problem-driven
manner. We designed a globally distributed family of surveys in joint
collaborations with different researchers and completed the first run in
Germany. The instrument is based on a theory in the form of a set of hypotheses
inferred from our experiences and available studies. We test each hypothesis in
our theory and identify further candidates to extend the theory by correlation
and Grounded Theory analysis. In this article, we report on the design of the
family of surveys, its underlying theory, and the full results obtained from
Germany with participants from 58 companies. The results reveal, for example, a
tendency to improve RE via internally defined qualitative methods rather than
relying on normative approaches like CMMI. We also discovered various RE
problems that are statistically significant in practice. For instance, we could
corroborate communication flaws or moving targets as problems in practice. Our
results are not yet fully representative but already give first insights into
current practices and problems in RE, and they allow us to draw lessons learnt
for future replications. Our results obtained from this first run in Germany
make us confident that the survey design and instrument are well-suited to be
replicated and, thereby, to create a generalisable empirical basis of RE in
practice
Flexible Invariants Through Semantic Collaboration
Modular reasoning about class invariants is challenging in the presence of
dependencies among collaborating objects that need to maintain global
consistency. This paper presents semantic collaboration: a novel methodology to
specify and reason about class invariants of sequential object-oriented
programs, which models dependencies between collaborating objects by semantic
means. Combined with a simple ownership mechanism and useful default schemes,
semantic collaboration achieves the flexibility necessary to reason about
complicated inter-object dependencies but requires limited annotation burden
when applied to standard specification patterns. The methodology is implemented
in AutoProof, our program verifier for the Eiffel programming language (but it
is applicable to any language supporting some form of representation
invariants). An evaluation on several challenge problems proposed in the
literature demonstrates that it can handle a variety of idiomatic collaboration
patterns, and is more widely applicable than the existing invariant
methodologies.Comment: 22 page
Semantic Matchmaking as Non-Monotonic Reasoning: A Description Logic Approach
Matchmaking arises when supply and demand meet in an electronic marketplace,
or when agents search for a web service to perform some task, or even when
recruiting agencies match curricula and job profiles. In such open
environments, the objective of a matchmaking process is to discover best
available offers to a given request. We address the problem of matchmaking from
a knowledge representation perspective, with a formalization based on
Description Logics. We devise Concept Abduction and Concept Contraction as
non-monotonic inferences in Description Logics suitable for modeling
matchmaking in a logical framework, and prove some related complexity results.
We also present reasonable algorithms for semantic matchmaking based on the
devised inferences, and prove that they obey to some commonsense properties.
Finally, we report on the implementation of the proposed matchmaking framework,
which has been used both as a mediator in e-marketplaces and for semantic web
services discovery
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