Practices

We examine an economy where professionals provide services to clients and where a professional can sell his practice to another. Professionals vary in quality, and clients in their need (or willingness-to-pay) for high-quality service. efficiency is measured as the number of matches between high-quality professionals and high-need clients. However, agent types are unobservable a priori. We find that trade in practices can facilitate the transmission of information about agent types; sometimes full efficiency is achieved. In cases where it is not, a tax on the sale of practices (based on the seller's age) can be used to achieve full efficiency. In addition, a ceiling on the price of services can be used to adjust the distribution of surplus between clients and professionals, while preserving efficiency.signaling, professional services, practices, goodwill

Practices

We examine an economy where professionals provide services to clients and where a professional can sell his practice to another. Professionals vary in quality, and clients in their need (or willingness-to-pay) for high-quality service. efficiency is measured as the number of matches between high-quality professionals and high-need clients. However, agent types are unobservable a priori. We find that trade in practices can facilitate the transmission of information about agent types; sometimes full efficiency is achieved. In cases where it is not, a tax on the sale of practices (based on the seller's age) can be used to achieve full efficiency. In addition, a ceiling on the price of services can be used to adjust the distribution of surplus between clients and professionals, while preserving efficiency

Programmez vos IHM avec Interacto: une démonstration

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Journal First: Interacto: A Modern User Interaction Processing Model

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Levothyroxine treatment generates an abnormal uterine contractility patterns in an in vitro animal model

AbstractObjectiveAbnormal uterine contraction patterns were recently demonstrated in uterine strips from pregnant women treated with Levothyroxine (T4). These abnormalities were correlated with an increased risk of C-section delivery and associated surgical complications. To date, no study has investigated whether uterine contractility is modified by hypothyroidism or T4 treatment. Herein, we analyze the physiological role of T4 on uterine contractions.Study designFemale non-pregnant Sprague–Dawley rats (N = 22) were used and divided into four groups: 1) control, 2) hypothyroidism, 3) hypothyroidism treated with low T4 doses (20 μg/kg/day) and 4) with high T4 doses (100 μg/kg/day). Hypothyroidism was induced by an iodine-deficient diet. Isometric tension measurements were performed in vitro on myometrium tissues in isolated organ baths. Contractile activity parameters were quantified (amplitude, duration, frequency and area under the curve) using pharmacological tools to assess their effect.ResultsScreening of thyroid function confirmed a hypothyroid state for all rats under iodine-free diet to which T4 was subsequently administered to counterbalance hypothyroidism. Results demonstrate that hypothyroidism significantly decreased contractile duration (−17%) and increased contractile frequency (+26%), while high doses of T4 increased duration (+200%) and decreased frequency (−51%). These results thus mimic the pattern of abnormal contractions previously observed in uterine tissue from T4-treated hypothyroid pregnant women.ConclusionOur data suggest that changes in myometrial reactivity are induced by T4 treatment. Thus, in conjunction with our previous observations on human myometrial strips, management of hypothyroidism should be improved to reduce the rate of C-sections in this group of patients

HyperAST: Enabling Efficient Analysis of Software Histories at Scale

International audienceSyntax Trees (ASTs) are widely used beyond compilers in many tools that measure and improve code quality, such as code analysis, bug detection, mining code metrics, refactoring. With the advent of fast software evolution and multistage releases, the temporal analysis of an AST history is becoming useful to understand and maintain code. However, jointly analyzing thousands versions of ASTs independently faces scalability issues, mostly combinatorial, both in terms of memory and CPU usage. In this paper, we propose a novel type of AST, called HyperAST , that enables efficient temporal code analysis on a given software history by: 1/ leveraging code redundancy through space (between code elements) and time (between versions); 2/ reusing intermediate computation results. We show how the HyperAST can be built incrementally on a set of commits to capture all multiple ASTs at once in an optimized way. We evaluated the HyperAST on a curated list of large software projects. Compared to Spoon, a state-of-the-art technique, we observed that the HyperAST outperforms it with an order-of-magnitude difference from ×6 up to ×8076 in CPU construction time and from ×12 up to ×1159 in memory footprint. While the HyperAST requires up to 2 h 22 min and 7.2 GB for the biggest project, Spoon requires up to 93 h and 31 min and 2.2 TB. The gains in construction time varied from 83.4 % to 99.99 % and the gains in memory footprint varied from 91.8 % to 99.9 %. We further compared the task of finding references of declarations with the HyperAST and Spoon. We observed on average 90 % precision and 97 % recall without a significant difference in search time

Software Diversity: Challenges to handle the imposed, Opportunities to harness the chosen

National audienceDiversity emerges as a critical concern that spans all activities in software engineering (from design to verification, from deployment to runtime resilience) and appears in all sorts of domains, which rely on software intensive systems, from systems of systems to pervasive combinations of Internet of Things and Internet of Services. If these domains are apparently radically different, we envision a strong convergence of the scientific principles underpinning their construction and validation towards flexible and open yet dependable systems. In this paper, we discuss the software engineering challenges raised by these requirements for flexibility and openness, focusing on four dimensions of diversity: the diversity of functionalities required by the different customers; the diversity of languages used by the stakeholders involved in the construction of these systems; the diversity of runtime environments in which software has to run and adapt; the diversity of failures against which the system must be able to react. In particular, we want to emphasize the challenges for handling imposed diversity, as well as the opportunities to leverage chosen diversity. The main challenge is that software diversity imposes to integrate the fact that software must adapt to changes in the requirements and environment -- in all development phases and in unpredictable ways. Yet, exploiting and increasing software diversity is a great opportunity to allow the spontaneous exploration of alternative software solutions and proactively prepare for unforeseen changes. Concretely, we want to provide software engineers with the ability: to characterize an 'envelope' of possible variations; to compose 'envelopes' (to discover new macro envelopes in an opportunistic manner); to dynamically synthesize software inside a given envelop

Untangling Spaghetti of Evolutions in Software Histories to Identify Code and Test Co-evolutions

International audienceVersion Control Systems are key elements of modern software development. They provide the history of software systems, serialized as lists of commits. Practitioners may rely on this history to understand and study the evolutions of software systems, including the co-evolution amongst strongly coupled development artifacts such as production code and their tests. However, a precise identification of code and test co-evolutions requires practitioners to manually untangle spaghetti of evolutions. In this paper, we propose an automated approach for detecting co-evolutions between code and test, independently of the commit history. The approach creates a sound knowledge base of code and test co-evolutions that practitioners can use for various purposes in their projects. We conducted an empirical study on a curated set of 45 open-source systems having Git histories. Our approach exhibits a precision of 100 % and an underestimated recall of 37.5 % in detecting the code and test co-evolutions. Our approach also spotted different kinds of code and test co-evolutions, including some of those researchers manually identified in previous work

A Demonstration for Building Modular and Efficient DSLs: The Kermeta v2 Experience

National audienceThis demonstration presents the new version (v2) of the Kermeta workbench that uses one domain-specific meta-language per language implementation concern. We show that the usage and combination of those meta-languages is simple and intuitive enough to deserve the term mashup and implemented as an original modular compilation scheme in the new version of Kermeta. This demonstration illustrates the use of the new version of Kermeta by presenting its use to design and implement two DSLs: Kompren, a DSL for designing and implementing model slicers; KCVL, the Commun Variability Language dedicated to variability management in software design models