Validity-Guided Synthesis of Reactive Systems from Assume-Guarantee Contracts

Automated synthesis of reactive systems from specifications has been a topic of research for decades. Recently, a variety of approaches have been proposed to extend synthesis of reactive systems from proposi- tional specifications towards specifications over rich theories. We propose a novel, completely automated approach to program synthesis which reduces the problem to deciding the validity of a set of forall-exists formulas. In spirit of IC3 / PDR, our problem space is recursively refined by blocking out regions of unsafe states, aiming to discover a fixpoint that describes safe reactions. If such a fixpoint is found, we construct a witness that is directly translated into an implementation. We implemented the algorithm on top of the JKind model checker, and exercised it against contracts written using the Lustre specification language. Experimental results show how the new algorithm outperforms JKinds already existing synthesis procedure based on k-induction and addresses soundness issues in the k-inductive approach with respect to unrealizable results.Comment: 18 pages, 5 figures, 2 table

Contemporary medical television and crisis in the NHS

This article maps the terrain of contemporary UK medical television, paying particular attention to Call the Midwife as its centrepiece, and situating it in contextual relation to the current crisis in the NHS. It provides a historical overview of UK and US medical television, illustrating how medical television today has been shaped by noteworthy antecedents. It argues that crisis rhetoric surrounding healthcare leading up to the passing of the Health and Social Care Act 2012 has been accompanied by a renaissance in medical television. And that issues, strands and clusters have emerged in forms, registers and modes with noticeable regularity, especially around the value of affective labour, the cultural politics of nostalgia and the neoliberalisation of healthcare

Work relations and the multiple dimensions of the work-life boundary: Hairstyling at home

This article proposes a multidimensional approach to analysis of the work-life boundary and examines the affects of particular social and organizational relations on the preservation or porous-ness of different dimensions. In line with Nippert-Eng (1996), it is suggested that different dimensions of the boundary are reinforced or weakened by different social and organizational pressures. Analysis describes a specific type of multidimensional breaching – instances when work is taken outside of the worksite (spatial breaching) and is carried out outside of work-time (temporal breaching). Empirical research was conducted among hairstylists working in salons and barbershops in a city in the North of England. Because of the nature of the tasks involved in hairstyling – that the skills involved are widely exchangeable and so may be employed in extra-work environments and temporalities – hairstylists provide a nice site for investigating the circumstances when this does (or does not) occur. Data collection involved a comprehensive self-completion survey of salons and barbershops in the city (response rate: 40%; N=132) and semi-structured interviews with 70 stylists working in 52 salons or barbershops. Findings demonstrate that work relations (hairstylists’ structural relations of production – whether a worker is an owner-proprietor, chair-renter, on-commission stylist, basic-only stylist, or trainee) are critical in determining both workers’ ability and desire to resist the seepage of work into their social lives as well as the particular dimensions of the boundary that are breached. This is because work relations affect the relative importance of four identified motivations for taking work out of the salon (income production; training; inter-personal reciprocity rooted in social relations; and inter-personal reciprocity rooted in the workplace)

The measurement of household consumption expenditures

Household-level data on consumer expenditures underpin a wide range of empirical research in modern economics, spanning micro-and macroeconomics. This research includes work on consumption and saving, on poverty and inequality, and on risk sharing and insurance. We review different ways in which such data can be collected or captured: traditional detailed budget surveys, less onerous survey procedures that might be included in more general surveys, and administrative or process data. We discuss the advantages and difficulties of each approach and suggest directions for future investigation. © 2014 by Annual Reviews. All rights reserved

On Deciding Local Theory Extensions via E-matching

Satisfiability Modulo Theories (SMT) solvers incorporate decision procedures for theories of data types that commonly occur in software. This makes them important tools for automating verification problems. A limitation frequently encountered is that verification problems are often not fully expressible in the theories supported natively by the solvers. Many solvers allow the specification of application-specific theories as quantified axioms, but their handling is incomplete outside of narrow special cases. In this work, we show how SMT solvers can be used to obtain complete decision procedures for local theory extensions, an important class of theories that are decidable using finite instantiation of axioms. We present an algorithm that uses E-matching to generate instances incrementally during the search, significantly reducing the number of generated instances compared to eager instantiation strategies. We have used two SMT solvers to implement this algorithm and conducted an extensive experimental evaluation on benchmarks derived from verification conditions for heap-manipulating programs. We believe that our results are of interest to both the users of SMT solvers as well as their developers

Systematic reviews of complementary therapies - an annotated bibliography. Part 1: Acupuncture

Background Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with acupuncture. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of acupuncture; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pretested form and summarized descriptively. Results From a total of 48 potentially relevant reviews preselected in a screeening process 39 met the inclusion criteria. 22 were on various pain syndromes or rheumatic diseases. Other topics addressed by more than one review were addiction, nausea, asthma and tinnitus. Almost unanimously the reviews state that acupuncture trials include too few patients. Often included trials are heterogeneous regarding patients, interventions and outcome measures, are considered to have insufficient quality and contradictory results. Convincing evidence is available only for postoperative nausea, for which acupuncture appears to be of benefit, and smoking cessation, where acupuncture is no more effective than sham acupuncture. Conclusions A large number of systematic reviews on acupuncture exists. What is most obvious from these reviews is the need for (the funding of) well-designed, larger clinical trials

California Men's Health Study (CMHS): a multiethnic cohort in a managed care setting

BACKGROUND: We established a male, multiethnic cohort primarily to study prostate cancer etiology and secondarily to study the etiologies of other cancer and non-cancer conditions. METHODS/DESIGN: Eligible participants were 45-to-69 year old males who were members of a large, prepaid health plan in California. Participants completed two surveys on-line or on paper in 2002 – 2003. Survey content included demographics; family, medical, and cancer screening history; sexuality and sexual development; lifestyle (diet, physical activity, and smoking); prescription and non-prescription drugs; and herbal supplements. We linked study data with clinical data, including laboratory, hospitalization, and cancer data, from electronic health plan files. We recruited 84,170 participants, approximately 40% from minority populations and over 5,000 who identified themselves as other than heterosexual. We observed a wide range of education (53% completed less than college) and income. PSA testing rates (75% overall) were highest among black participants. Body mass index (BMI) (median 27.2) was highest for blacks and Latinos and lowest for Asians, and showed 80.6% agreement with BMI from clinical data sources. The sensitivity and specificity can be assessed by comparing self-reported data, such as PSA testing, diabetes, and history of cancer, to health plan data. We anticipate that nearly 1,500 prostate cancer diagnoses will occur within five years of cohort inception. DISCUSSION: A wide variety of epidemiologic, health services, and outcomes research utilizing a rich array of electronic, biological, and clinical resources is possible within this multiethnic cohort. The California Men's Health Study and other cohorts nested within comprehensive health delivery systems can make important contributions in the area of men's health

Experimental Quantum Teleportation of a Two-Qubit Composite System

Quantum teleportation, a way to transfer the state of a quantum system from one location to another, is central to quantum communication and plays an important role in a number of quantum computation protocols. Previous experimental demonstrations have been implemented with photonic or ionic qubits. Very recently long-distance teleportation and open-destination teleportation have also been realized. Until now, previous experiments have only been able to teleport single qubits. However, since teleportation of single qubits is insufficient for a large-scale realization of quantum communication and computation2-5, teleportation of a composite system containing two or more qubits has been seen as a long-standing goal in quantum information science. Here, we present the experimental realization of quantum teleportation of a two-qubit composite system. In the experiment, we develop and exploit a six-photon interferometer to teleport an arbitrary polarization state of two photons. The observed teleportation fidelities for different initial states are all well beyond the state estimation limit of 0.40 for a two-qubit system. Not only does our six-photon interferometer provide an important step towards teleportation of a complex system, it will also enable future experimental investigations on a number of fundamental quantum communication and computation protocols such as multi-stage realization of quantum-relay, fault-tolerant quantum computation, universal quantum error-correction and one-way quantum computation.Comment: 16pages, 4 figure