Contractual Testing

Variants of must testing approach have been successfully applied in Service Oriented Computing for capturing compliance between (contracts exposed by) a client and a service and for characterising safe replacement, namely the fact that compliance is preserved when a service exposing a ’smaller’ contract is replaced by another one with a ’larger’ contract. Nevertheless, in multi-party interactions, partners often lack full coordination capabilities. Such a scenario calls for less discriminating notions of testing in which observers are, e.g., the description of uncoordinated multiparty contexts or contexts that are unable to observe the complete behaviour of the process under test. In this paper we propose an extended notion of must preorder, called contractual preorder, according to which contracts are compared according to their ability to pass only the tests belonging to a given set. We show the generality of our framework by proving that preorders induced by existing notions of compliance in a distributed setting are instances of the contractual preorder when restricting to suitable sets of observers

Characterising Testing Preorders for Finite Probabilistic Processes

In 1992 Wang & Larsen extended the may- and must preorders of De Nicola and Hennessy to processes featuring probabilistic as well as nondeterministic choice. They concluded with two problems that have remained open throughout the years, namely to find complete axiomatisations and alternative characterisations for these preorders. This paper solves both problems for finite processes with silent moves. It characterises the may preorder in terms of simulation, and the must preorder in terms of failure simulation. It also gives a characterisation of both preorders using a modal logic. Finally it axiomatises both preorders over a probabilistic version of CSP.Comment: 33 page

Layered Fixed Point Logic

We present a logic for the specification of static analysis problems that goes beyond the logics traditionally used. Its most prominent feature is the direct support for both inductive computations of behaviors as well as co-inductive specifications of properties. Two main theoretical contributions are a Moore Family result and a parametrized worst case time complexity result. We show that the logic and the associated solver can be used for rapid prototyping and illustrate a wide variety of applications within Static Analysis, Constraint Satisfaction Problems and Model Checking. In all cases the complexity result specializes to the worst case time complexity of the classical methods

The Forward Testing Effect: Interim Testing Enhances Inductive Learning.

Induction refers to the process in which people generalize their previous experience when making uncertain inferences about the environment that go beyond direct experience. Here we show that interim tests strongly enhance inductive learning. Participants studied the painting styles of eight famous artists across four lists, each comprising paintings by one pair of artists. In an interim test group participants’ induction was tested after each list. In two control groups participants solved math problems (interim math group) or studied additional new paintings (interim study group) following each of Lists 1–3 and were asked to classify new paintings on List 4. In the List 4 interim test, the interim test group significantly outperformed the other two groups, indicating that interim testing enhances new inductive learning. In a final cumulative test, accuracy in the interim test group at classifying new paintings by studied artists was nearly double that of the other two groups, indicating the major importance of interim testing in inductive learning. This enhancing effect of interim testing on inductive learning was associated with metacognitive awareness

Physics as a Mechanism for Including ELLs in Classroom Discourse

English Language Learners (ELLs) are frequently left on the periphery of classroom interactions. Due to misalignment of language skills, teachers and peers communicate with these students less often, decreasing the number of opportunities to engage. Exclusion can be avoided with learning activities that invite all students to participate and contribute ideas. We argue that environments and activities that privilege scientific inductive reasoning increase possibilities for emerging bilingual students to engage. This study investigated first-grade students' discussions about factors that affect how objects float. Students came from a variety of language backgrounds; all were considered beginner/intermediate ELLs. Results show that the goal of inducing principles from actual phenomena encouraged students to communicate their ideas and reasoning, boosting students' confidence in expressing themselves. Following the hybrid space argument of Vygotsky's theory of concept formation, we illustrate that physics can be particularly suitable context for the co-development of concepts and English language skills.Comment: 4 Pages; Physics Education Research Conference Proceedings - 2013, Portland O

Inductive sensor

Tato práce se zabývá problematikou indukčnostního snímače s vnesenou impedancí, která je využívána pro nedestruktivní zkoušení materiálů. Popisuje a realizuje postup při měření metodou vířivých proudů s použitím příložné cívky. Práce obsahuje výsledné hodografy odpovídající literatuře pro magneticky vodivý a magneticky nevodivý měřený materiál. Poslední část práce se zabývá rozborem vhodné volby pracovního bodu snímače odvozeného od naměřených hodnot.This bachelor thesis deals with indukčnostního-loaded impedance sensor, which is used for non-destructive materials testing. Describes a procedure for measuring the eddy current method using a straight coil. This thesis includes the final locus corresponding literature ferromagnetic and non-ferromagnetic for the measured material. The last part deals with the analysis of the appropriate choice of operating point derived from the sensor readings.

Bisimilarity as a Theory of Functional Programming

AbstractMorris-style contextual equivalence — invariance of termination under any context of ground type — is the usual notion of operational equivalence for deterministic functional languages such as FPC (PCF plus sums, products and recursive types). Contextual equivalence is hard to establish directly. Instead we define a labelled transition system for call-by-name FPC (and variants) and prove that CCS-style bisimilarity equals contextual equivalence — a form of operational extensionality. Using co-induction we establish equational laws for FPC. By considering variations of Milner's ‘bisimulations up to ∼’ we obtain a second co-inductive characterisation of contextual equivalence in terms of reduction behaviour and production of values. Hence we use co-inductive proofs to establish contextual equivalence in a series of stream-processing examples. Finally, we consider a form of Milner's original context lemma for FPC, but conclude that our form of bisimilarity supports simpler co-inductive proofs

The Use of Proof Planning for Cooperative Theorem Proving

AbstractWe describebarnacle: a co-operative interface to theclaminductive theorem proving system. For the foreseeable future, there will be theorems which cannot be proved completely automatically, so the ability to allow human intervention is desirable; for this intervention to be productive the problem of orienting the user in the proof attempt must be overcome. There are many semi-automatic theorem provers: we call our style of theorem provingco-operative, in that the skills of both human and automaton are used each to their best advantage, and used together may find a proof where other methods fail. The co-operative nature of thebarnacleinterface is made possible by the proof planning technique underpinningclam. Our claim is that proof planning makes new kinds of user interaction possible.Proof planning is a technique for guiding the search for a proof in automatic theorem proving. Common patterns of reasoning in proofs are identified and represented computationally as proof plans, which can then be used to guide the search for proofs of new conjectures. We have harnessed the explanatory power of proof planning to enable the user to understand where the automatic prover got to and why it is stuck. A user can analyse the failed proof in terms ofclam's specification language, and hence override the prover to force or prevent the application of a tactic, or discover a proof patch. This patch might be to apply further rules or tactics to bridge the gap between the effects of previous tactics and the preconditions needed by a currently inapplicable tactic