Control flow in the wild : a first look at 13K Java projects (Extended abstract)

No abstract

Empirical analysis of the relationship between CC and SLOC in a large corpus of Java methods and C functions

Measuring the internal quality of source code is one of the traditional goals of making software development into an engineering discipline. Cyclomatic complexity (CC) is an often used source code quality metric, next to source lines of code (SLOC). However, the use of the CC metric is challenged by the repeated claim that CC is redundant with respect to SLOC because of strong linear correlation.We conducted an extensive literature study of the CC/SLOC correlation results. Next, we tested correlation on large Java (17.6 M methods) and C (6.3 M functions) corpora. Our results show that linear correlation between SLOC and CC is only moderate as a result of increasingly high variance. We further observe that aggregating CC and SLOC as well as performing a power transform improves the correlation.Our conclusion is that the observed linear correlation between CC and SLOC of Java methods or C functions is not strong enough to conclude that CC is redundant with SLOC. This conclusion contradicts earlier claims from literature but concurs with the widely accepted practice of measuring of CC next to SLOC

Metformin Associated With Lower Cancer Mortality in Type 2 Diabetes: ZODIAC-16

OBJECTIVE - Several Studies have suggested an association between specific diabetes treatment and cancer mortality. We studied the association between metformin use and cancer mortality in a prospectively followed cohort. RESEARCH DESIGN AND METHODS - in 1998 and 1999,1,353 patients With type 2 diabetes were enrolled in the Zwolle Outpatient Diabetes project Integrating Available Care 0 (ZODIAC) study in the Netherlands. Vital status was assessed in January 2009. Cancer mortality rate was evaluated using Standardized Mortality ratios (SMRs), and the association between metformin use and cancer mortality was evaluated with a Cox proportional hazards model, taking possible confounders into account. RESULTS - Median follow-up time was 9.6 years, average age at baseline was 68 years, and average A1C was 7.5%. Of the patients, 570 died, of which 122 died of malignancies. The SMR for cancer mortality was 1.47 (95% CI 1.22-1.76). In patients taking metformin compared with patients not taking metformin at baseline, the adjusted hazard ratio (HR) for cancer mortality was 0.43 (95% Cl 0.23-0.80), and the HR With every increase of I g of metformin was 0.58 (95% CI 0.36-093), CONCLUSIONS - in general, patients with type 2 diabetes are at increased risk for cancer mortality. In our group, metformin use was associated with lower cancer mortality compared with nonuse of metformin. Although the design cannot provide a conclusion about causality, our results suggest a protective effect of metformin on cancer mortality

First-principles Simulations of the stretching and final breaking of Al nanowires: Mechanical properties and electrical conductance

The evolution of the structure and conductance of an Al nanowire subject to a tensile stress has been studied by first-principles total-energy simulations. Our calculations show the correlation between discontinuous changes in the force (associated to changes in the bonding structure of the nanowire) and abrupt modifications of the conductance as the nanowire develops a thinner neck, in agreement with the experiments. We reproduce the characteristic increase of the conductance in the last plateau, reaching a value close to the conductance quantum $G_0 = 2 e^2 / h$ before the breaking of the nanowire. A dimer defines the contact geometry at these last stages, with three channels (one dominant) contributing to the conductance.Comment: 4 pages, 4 figure

Modeling the Subsurface Structure of Sunspots

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

Empirical analysis of the relationship between CC and SLOC in a large corpus of Java methods

Measuring the internal quality of source code is one of the traditional goals of making software development into an engineering discipline. Cyclomatic Complexity (CC) is an often used source code quality metric, next to Source Lines of Code (SLOC). However, the use of the CC metric is challenged by the repeated claim that CC is redundant with respect to SLOC due to strong linear correlation. We test this claim by studying a corpus of 17.8M methods in 13K open-source Java projects. Our results show that direct linear correlation between SLOC and CC is only moderate, as caused by high variance. We observe that aggregating CC and SLOC over larger units of code improves the correlation, which explains reported results of strong linear correlation in literature. We suggest that the primary cause of correlation is the aggregation. Our conclusion is that there is no strong linear correlation between CC and SLOC of Java methods, so we do not conclude that CC is redundant with SLOC. This conclusion contradicts earlier claims from literature, but concurs with the widely accepted practice of measuring of CC next to SLOC