scholarly journals Do Judge a Test by its Cover

2021 ◽  
pp. 264-291
Author(s):  
Harrison Goldstein ◽  
John Hughes ◽  
Leonidas Lampropoulos ◽  
Benjamin C. Pierce
Keyword(s):  
Cartesian Product ◽  
Combinatorial Testing ◽  
Data Types ◽  
Regular Tree ◽  
Random Test ◽  
Random Generators ◽  
Algebraic Data Types ◽  
Definition Of ◽  
High Level ◽  
System F

AbstractProperty-based testing uses randomly generated inputs to validate high-level program specifications. It can be shockingly effective at finding bugs, but it often requires generating a very large number of inputs to do so. In this paper, we apply ideas from combinatorial testing, a powerful and widely studied testing methodology, to modify the distributions of our random generators so as to find bugs with fewer tests. The key concept is combinatorial coverage, which measures the degree to which a given set of tests exercises every possible choice of values for every small combination of input features.In its “classical” form, combinatorial coverage only applies to programs whose inputs have a very particular shape—essentially, a Cartesian product of finite sets. We generalize combinatorial coverage to the richer world of algebraic data types by formalizing a class of sparse test descriptions based on regular tree expressions. This new definition of coverage inspires a novel combinatorial thinning algorithm for improving the coverage of random test generators, requiring many fewer tests to catch bugs. We evaluate this algorithm on two case studies, a typed evaluator for System F terms and a Haskell compiler, showing significant improvements in both.

scholarly journals The ins and outs of Clean I/O

1995 ◽  
Vol 5 (1) ◽  
pp. 81-110 ◽  
Author(s):  
Peter Achten ◽  
Rinus Plasmeijer
Keyword(s):  
Programming Languages ◽  
Programming Language ◽  
Functional Programming ◽  
Data Types ◽  
Spreadsheet Program ◽  
Functional Programming Languages ◽  
Hard Time ◽  
Functional Programming Language ◽  
Algebraic Data Types ◽  
High Level

AbstractFunctional programming languages have banned assignment because of its undesirable properties. The reward of this rigorous decision is that functional programming languages are side-effect free. There is another side to the coin: because assignment plays a crucial role in Input/Output (I/O), functional languages have a hard time dealing with I/O. Functional programming languages have therefore often been stigmatised as inferior to imperative programming languages because they cannot deal with I/O very well. In this paper, we show that I/O can be incorporated in a functional programming language without loss of any of the generally accepted advantages of functional programming languages. This discussion is supported by an extensive account of the I/O system offered by the lazy, purely functional programming language Clean. Two aspects that are paramount in its I/O system make the approach novel with respect to other approaches. These aspects are the technique of explicit multiple environment passing, and the Event I/O framework to program Graphical User I/O in a highly structured and high-level way. Clean file I/O is as powerful and flexible as it is in common imperative languages (one can read, write, and seek directly in a file). Clean Event I/O provides programmers with a high-level framework to specify complex Graphical User I/O. It has been used to write applications such as a window-based text editor, an object based drawing program, a relational database, and a spreadsheet program. These graphical interactive programs are completely machine independent, but still obey the look-and-feel of the concrete window environment being used. The specifications are completely functional and make extensive use of uniqueness typing, higher-order functions, and algebraic data types. Efficient implementations are present on the Macintosh, Sun (X Windows under Open Look) and PC (OS/2).

scholarly journals Termination analysis based on operational semantics

1995 ◽  
Vol 24 (492) ◽  
Author(s):  
Flemming Nielson ◽  
Hanne Riis Nielson
Keyword(s):  
Operational Semantics ◽  
Denotational Semantics ◽  
Theorem Prover ◽  
Functional Language ◽  
Data Types ◽  
Termination Analysis ◽  
Standard Ml ◽  
Polymorphic Type ◽  
Algebraic Data Types ◽  
Definition Of

In principle termination analysis is easy: find a well-founded partial order and prove that calls decrease with respect to this order. In practice this often requires an oracle (or a theorem prover) for determining the well-founded order and this oracle may not be easily implementable. Our approach circumvents some of these problems by exploiting the inductive definition of algebraic data types and using pattern matching as in functional languages. We develop a termination analysis for a higher-order functional language; the analysis incorporates and extends polymorphic type inference and axiomatizes a class of well-founded partial orders for multiple-argument functions (as in Standard ML and Miranda). Semantics is given by means of operational (natural-style) semantics and soundness is proved; this involves making extensions to the semantic universe and we relate this to the techniques of denotational semantics. For dealing with the partiality aspects of the soundness proof, it suffices to incorporate approximations to the desired fixed points; for dealing with the totality aspects of the soundness proof, we also have to incorporate functions that are forced to terminate (in a way that might violate the monotonicity of denotational semantics).

Europe

2020 ◽  
pp. 649-666
Author(s):  
Andrea Renda
Keyword(s):  
Artificial Intelligence ◽  
Digital Technology ◽  
Policy Framework ◽  
Expert Group ◽  
Ethical Guidelines ◽  
Ethical Implications ◽  
Strong Focus ◽  
Ethics Guidelines ◽  
Definition Of ◽  
High Level

This chapter assesses Europe’s efforts in developing a full-fledged strategy on the human and ethical implications of artificial intelligence (AI). The strong focus on ethics in the European Union’s AI strategy should be seen in the context of an overall strategy that aims at protecting citizens and civil society from abuses of digital technology but also as part of a competitiveness-oriented strategy aimed at raising the standards for access to Europe’s wealthy Single Market. In this context, one of the most peculiar steps in the European Union’s strategy was the creation of an independent High-Level Expert Group on AI (AI HLEG), accompanied by the launch of an AI Alliance, which quickly attracted several hundred participants. The AI HLEG, a multistakeholder group including fifty-two experts, was tasked with the definition of Ethics Guidelines as well as with the formulation of “Policy and Investment Recommendations.” With the advice of the AI HLEG, the European Commission put forward ethical guidelines for Trustworthy AI—which are now paving the way for a comprehensive, risk-based policy framework.

scholarly journals Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Strain Field ◽  
Element Analysis ◽  
Inverse Finite Element Method ◽  
Shape Sensing ◽  
Definition Of ◽  
High Level ◽  
Element Method

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.

scholarly journals A fatal toxic shock-like syndrome post COVID-19 infection in a child

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Houda Ajmi ◽  
Wissem Besghaier ◽  
Wafa Kallala ◽  
Abdelhalim Trabelsi ◽  
Saoussan Abroug
Keyword(s):  
Ejection Fraction ◽  
Pediatric Intensive Care ◽  
Fresh Frozen Plasma ◽  
Multiple Organ ◽  
Clinical Feature ◽  
Fresh Frozen ◽  
Life Threatening ◽  
High Doses ◽  
Definition Of ◽  
High Level

Abstract Background Children affected by Coronavirus disease 2019 (COVID-19) showed various manifestations. Some of them were severe cases presenting with multi-system inflammatory syndrome (MIS-C) causing multiple organ dysfunction. Case presentation We report the case of a 12-year-old girl with recent COVID-19 infection who presented with persistent fever, abdominal pain and other symptoms that meet the definition of MIS-C. She had lymphopenia and a high level of inflammatory markers. She was admitted to pediatric intensive care unit since she rapidly developed refractory catecholamine-resistant shock with multiple organ failure. Echocardiography showed a small pericardial effusion with a normal ejection fraction (Ejection Fraction = 60%) and no valvular or coronary lesions. The child showed no signs of improvement even after receiving intravenous immunoglobulin, fresh frozen plasma, high doses of Vasopressors and corticosteroid. His outcome was fatal. Conclusion Pediatric patients affected by the new COVID-19 related syndrome may show severe life-threatening conditions similar to Kawasaki disease shock syndrome. Hypotension in these patients results from heart failure and the decreased cardiac output. We report a new severe clinical feature of SARS-CoV-2 infection in children in whom hypotension was the result of refractory vasoplegia.

scholarly journals Differential Co-Expression Analyses Allow the Identification of Critical Signalling Pathways Altered during Tumour Transformation and Progression

2020 ◽  
Vol 21 (24) ◽  
pp. 9461
Author(s):  
Aurora Savino ◽  
Paolo Provero ◽  
Valeria Poli
Keyword(s):  
Cancer Biology ◽  
Regulatory Networks ◽  
Tumour Progression ◽  
External Perturbation ◽  
Data Types ◽  
Differential Gene ◽  
Gene Regulatory ◽  
Experimental Validations ◽  
Definition Of ◽  
Future Work

Biological systems respond to perturbations through the rewiring of molecular interactions, organised in gene regulatory networks (GRNs). Among these, the increasingly high availability of transcriptomic data makes gene co-expression networks the most exploited ones. Differential co-expression networks are useful tools to identify changes in response to an external perturbation, such as mutations predisposing to cancer development, and leading to changes in the activity of gene expression regulators or signalling. They can help explain the robustness of cancer cells to perturbations and identify promising candidates for targeted therapy, moreover providing higher specificity with respect to standard co-expression methods. Here, we comprehensively review the literature about the methods developed to assess differential co-expression and their applications to cancer biology. Via the comparison of normal and diseased conditions and of different tumour stages, studies based on these methods led to the definition of pathways involved in gene network reorganisation upon oncogenes’ mutations and tumour progression, often converging on immune system signalling. A relevant implementation still lagging behind is the integration of different data types, which would greatly improve network interpretability. Most importantly, performance and predictivity evaluation of the large variety of mathematical models proposed would urgently require experimental validations and systematic comparisons. We believe that future work on differential gene co-expression networks, complemented with additional omics data and experimentally tested, will considerably improve our insights into the biology of tumours.

PROPERTIES OF QUASI-RELABELING TREE BIMORPHISMS

2010 ◽  
Vol 21 (03) ◽  
pp. 257-276 ◽  
Author(s):  
ANDREAS MALETTI ◽  
CĂTĂLIN IONUŢ TÎRNĂUCĂ
Keyword(s):  
Cartesian Product ◽  
Canonical Representation ◽  
Finite Union ◽  
Top Down ◽  
Tree Language ◽  
Regular Tree ◽  
Fundamental Properties ◽  
Tree Transducers ◽  
Tree Languages ◽  
Context Free

The fundamental properties of the class QUASI of quasi-relabeling relations are investigated. A quasi-relabeling relation is a tree relation that is defined by a tree bimorphism (φ, L, ψ), where φ and ψ are quasi-relabeling tree homomorphisms and L is a regular tree language. Such relations admit a canonical representation, which immediately also yields that QUASI is closed under finite union. However, QUASI is not closed under intersection and complement. In addition, many standard relations on trees (e.g., branches, subtrees, v-product, v-quotient, and f-top-catenation) are not quasi-relabeling relations. If quasi-relabeling relations are considered as string relations (by taking the yields of the trees), then every Cartesian product of two context-free string languages is a quasi-relabeling relation. Finally, the connections between quasi-relabeling relations, alphabetic relations, and classes of tree relations defined by several types of top-down tree transducers are presented. These connections yield that quasi-relabeling relations preserve the regular and algebraic tree languages.

The Impact of the Privacy Rule on Cancer Research: Variations in Attitudes and Application of Regulatory Standards

2009 ◽  
Vol 27 (24) ◽  
pp. 4014-4020 ◽  
Author(s):  
Elizabeth Goss ◽  
Michael P. Link ◽  
Suanna S. Bruinooge ◽  
Theodore S. Lawrence ◽  
Joel E. Tepper ◽  
...  
Keyword(s):  
Cancer Research ◽  
Future Research ◽  
Research Committee ◽  
Data Repositories ◽  
Privacy Rule ◽  
Regulatory Standards ◽  
American Society ◽  
Definition Of ◽  
High Level ◽  
The Impact

Purpose The American Society of Clinical Oncology (ASCO) Cancer Research Committee designed a qualitative research project to assess the attitudes of cancer researchers and compliance officials regarding compliance with the US Privacy Rule and to identify potential strategies for eliminating perceived or real barriers to achieving compliance. Methods A team of three interviewers asked 27 individuals (13 investigators and 14 compliance officials) from 13 institutions to describe the anticipated approach of their institutions to Privacy Rule compliance in three hypothetical research studies. Results The interviews revealed that although researchers and compliance officials share the view that patients' cancer diagnoses should enjoy a high level of privacy protection, there are significant tensions between the two groups related to the proper standards for compliance necessary to protect patients. The disagreements are seen most clearly with regard to the appropriate definition of a “future research use” of protected health information in biospecimen and data repositories and the standards for a waiver of authorization for disclosure and use of such data. Conclusion ASCO believes that disagreements related to compliance and the resulting delays in certain projects and abandonment of others might be eased by additional institutional training programs and consultation on Privacy Rule issues during study design. ASCO also proposes the development of best practices documents to guide 1) creation of data repositories, 2) disclosure and use of data from such repositories, and 3) the design of survivorship and genetics studies.

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