Finito: A Faster, Permutable Incremental Gradient Method for Big Data Problems

Recent advances in optimization theory have shown that smooth strongly convex finite sums can be minimized faster than by treating them as a black box "batch" problem. In this work we introduce a new method in this class with a theoretical convergence rate four times faster than existing methods, for sums with sufficiently many terms. This method is also amendable to a sampling without replacement scheme that in practice gives further speed-ups. We give empirical results showing state of the art performance

Convex relaxation of mixture regression with efficient algorithms

We develop a convex relaxation of maximum a posteriori estimation of a mixture of regression models. Although our relaxation involves a semidefinite matrix variable, we reformulate the problem to eliminate the need for general semidefinite programming. In particular, we provide two reformulations that admit fast algorithms. The first is a max-min spectral reformulation exploiting quasi-Newton descent. The second is a min-min reformulation consisting of fast alternating steps of closed-form updates. We evaluate the methods against Expectation-Maximization in a real problem of motion segmentation from video data

The rich-club phenomenon across complex network hierarchies

The so-called rich-club phenomenon in a complex network is characterized when nodes of higher degree (hubs) are better connected among themselves than are nodes with smaller degree. The presence of the rich-club phenomenon may be an indicator of several interesting high-level network properties, such as tolerance to hub failures. Here we investigate the existence of the rich-club phenomenon across the hierarchical degrees of a number of real-world networks. Our simulations reveal that the phenomenon may appear in some hierarchies but not in others and, moreover, that it may appear and disappear as we move across hierarchies. This reveals the interesting possibility of non-monotonic behavior of the phenomenon; the possible implications of our findings are discussed.Comment: 4 page

Gender Differences in Smoking Among an Urban Emergency Department Sample.

BackgroundUrban emergency department (ED) patients have elevated smoking and substance use compared with the general population. We analyzed gender differences in smoking among an urban ED sample and assessed the contribution of substance use, demographic, and couple factors.MethodsWe conducted a secondary analysis of data obtained from a cross-sectional, observational survey (N = 1037 participants) on drinking, drug use, and intimate partner violence (IPV). Gender-specific logistic regression models for current (past 30-day) smoking and multinomial regression models for smoking intensity (light: ⩽5 cigarettes per day [CPD]; moderate: 6 to 10 CPD; heavier: >10 CPD) were estimated.ResultsSmoking prevalence was higher among men than women (35.5% vs 18.9%; P < .001). Substance use (frequency of intoxication, marijuana, amphetamine, and cocaine use), demographic (food insufficiency, unemployment), and couple-related factors (having a spouse/partner who smoked, IPV involvement, being in a same-gender couple) were differentially associated with current smoking and level of intensity among men and women.ConclusionsEmergency department staff should consider the impact of polysubstance use, food insufficiency, unemployment, and whether both partners in the couple smoke when screening patients for smoking and formulating cessation treatment plans. Women in same-gender relationships and those who have experienced IPV involvement may require additional referral

Corporate blended learning in Portugal: current status and future directions

The aim of this study is to characterize the current status of blended learning in Portugal, given that b-learning has grown exponentially in the Portuguese market over recent years. 38 organizations (representing 68% of all institutions certified to provide distance training by the Government Labour Office – DGERT -) participated in this study. The results revealed that in 2007, although the predominant instructional format in Portugal was still face-to-face training (65%), e-learning at 15% came in behind b-learning with 20%. Data also revealed that 50% of distance training department coordinators believe that b-learning produces better training outcomes than face-to-face training alone, when considering the same content and learning objectives. Furthermore, when comparing b-learning and e-learning outcomes with similar content and learning objectives, 78.1% of these coordinators declared that b-learning produces better outcomes than e-learning alone. Hence, the content analysis indicated positive perceptions with regard to the future direction of b-learning, leading to the conclusion that in the long-term, corporate b-learning training will develop considerably in this country

Microcredentials

Describing Life Long Learning implementation at Universidade Aberta across the years and the recent implementation of Microcredentials.N/

The Eastward Enlargement of the Eurozone: Trade and FDI

Trade and FDI, Economic Integration