Enhancing Search-based Testing with Testability Transformations for Existing APIs

Search-based software testing (SBST) has been shown to be an effective technique to generate test cases automatically. Its effectiveness strongly depends on the guidance of the fitness function. Unfortunately, a common issue in SBST is the so-called flag problem , where the fitness landscape presents a plateau that provides no guidance to the search. In this article, we provide a series of novel testability transformations aimed at providing guidance in the context of commonly used API calls (e.g., strings that need to be converted into valid date/time objects). We also provide specific transformations aimed at helping the testing of REST Web Services. We implemented our novel techniques as an extension to EvoMaster , an SBST tool that generates system-level test cases. Experiments on nine open-source REST web services, as well as an industrial web service, show that our novel techniques improve performance significantly.

The leaky semicolon: compositional semantic dependencies for relaxed-memory concurrency

Program logics and semantics tell a pleasant story about sequential composition: when executing (S1;S2), we first execute S1 then S2. To improve performance, however, processors execute instructions out of order, and compilers reorder programs even more dramatically. By design, single-threaded systems cannot observe these reorderings; however, multiple-threaded systems can, making the story considerably less pleasant. A formal attempt to understand the resulting mess is known as a “relaxed memory model.” Prior models either fail to address sequential composition directly, or overly restrict processors and compilers, or permit nonsense thin-air behaviors which are unobservable in practice. To support sequential composition while targeting modern hardware, we enrich the standard event-based approach with preconditions and families of predicate transformers. When calculating the meaning of (S1; S2), the predicate transformer applied to the precondition of an event e from S2 is chosen based on the set of events in S1 upon which e depends. We apply this approach to two existing memory models.

Women in the boardroom

Purpose This paper aims to review the latest management developments across the globe and pinpoint practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings Financial sector firms can improve performance by increasing the number of women directors in the boardroom. However, the likelihood of an indirect impact makes it important to identify factors able to mediate or moderate the relationship. Originality/value The briefing saves busy executives, strategists and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

Responsiveness: A Measure to Improve Performance of Rehabili-tation Organizations in Developing Countries

The article's abstract is not available.

INCENTIVE MECHANISM FOR PERFORMANCE-BASED PAYMENT OF INFRASTRUCTURE PPP PROJECTS: COUPLING OF REPUTATION AND RATCHET EFFECTS

The performance-based payment PPP model has been widely used in the infrastructure projects. However, the ratchet effect derived from performance-based reputation incentives has been largely overlooked. To overcome this shortcoming, ratchet effect is considered in the performance-based payment incentive process. A multi-period dynamic incentive mechanism is developed by coupling the reputation and ratchet effect. The main results show that: (1) Under the coupling of reputation and ratchet effects, the optimal incentive coefficient in the last performance assessment period is always greater than that of the first period. The bargaining power can replace part of the incentive effect; (2) Due to the ratchet effect, if the government improve performance targets through performance adjustment coefficients, it needs to increase incentives to overcome the decreasing effort of the private sector; (3) When the bargaining power and punishment coefficient are small, the reputation incentive is replacing the explicit incentive. The increasing incentive coefficient would make the ratchet effect dominant the reputation effect; (4) To prevent the incentive incompatibility derived from the ratchet effect, the government should increase the incentive while increasing the punishment to achieve the “penalties and rewards”. This study provides theoretical and methodological guidance to design incentive contracts for infrastructure PPP projects.

Integration of Feature Vectors from Raw Laboratory, Medication and Procedure Names Improves the Precision and Recall of Models to Predict Postoperative Mortality and Acute Kidney Injury

Introduction: Manuscripts that have successfully used machine learning (ML) to predict a variety of perioperative outcomes often use only a limited number of features selected by a clinician. We hypothesized that techniques leveraging a broad set of features for patient laboratory results, medications, and the surgical procedure name would improve performance as compared to a more limited set of features chosen by clinicians. Methods Feature vectors for laboratory results included 702 features total derived from 39 laboratory tests, medications consisted of a binary flag for 126 commonly used medications, procedure name used the Word2Vec package for create a vector of length 100. Nine models were trained: Baseline Features, one for each of the three types of data Baseline+Each data type (, all features, and then all features with feature reduction algorithm. Results Across both outcomes the models that contained all features (model 8) (Mortality ROC-AUC 94.42, PR-AUC 31.0; AKI ROC-AUC 92.47, PR-AUC 76.73) was superior to models with only subsets of features Conclusion Featurization techniques leveraging a broad away of clinical data can improve performance of perioperative prediction models.

Evaluation of minimum ramp distance in efforts to improve performance on Jakarta - Cikampek toll road

Toll road ramps that connect toll roads and arterial roads are often crowded until they are jammed by the activities of workers and school deliverers. And the rush hour that occurs in the morning and evening causes congestion on toll access roads both on and off ramps. The purpose of this research to find out how the performance condition of the toll access road with the distance that is currently available.. The method used in this paper is descriptive quantitative. By using the results of the Average Daily Traffic (ADT) survey at the intersection of West Bekasi, Cibitung and West Kerawang during the morning and evening rush hours. The results of the survey and analysis using the 1997 Indonesian Road Capacity Manual (IRCM) standard obtained a ratio of volume to capacity (v/c ratio), speed and traffic density, these characteristics were then used to find the Level Of Service (LOS) obtained by LOS F (VCR >1). The conclusion from the analysis is that the performance of the connecting road/ramp often occurs during rush hour with the lowest LOS F values in the morning and evening, so it is necessary to evaluate the minimum ramp distance.