A hybrid approach of rough set theory and genetic algorithm for fault diagnosis

[[abstract]]This paper proposes an integrated intelligent system that builds a fault diagnosis inference model based on the advantage of rough set theory and genetic algorithms (GAs). Rough set theory is a novel data mining approach that deals with vagueness and can be used to find hidden patterns in data sets. Based on this approach, minimal condition variable subsets and induction rules are established and illustrated using an application for motherboard electromagnetic interference (EMI) test fault diagnosis. This integrated system successfully integrated the rough set theory for handling uncertainty with a robust search engine, GA. The result shows that the proposed method can reduce the number of conditional attributes used in motherboard EMI fault diagnosis and maintain acceptable classification accuracy. The average diagnostic accuracy of 80% shows that this hybrid model is a promising approach to EMI diagnostic support systems

Flocking and turning: a new model for self-organized collective motion

Birds in a flock move in a correlated way, resulting in large polarization of velocities. A good understanding of this collective behavior exists for linear motion of the flock. Yet observing actual birds, the center of mass of the group often turns giving rise to more complicated dynamics, still keeping strong polarization of the flock. Here we propose novel dynamical equations for the collective motion of polarized animal groups that account for correlated turning including solely social forces. We exploit rotational symmetries and conservation laws of the problem to formulate a theory in terms of generalized coordinates of motion for the velocity directions akin to a Hamiltonian formulation for rotations. We explicitly derive the correspondence between this formulation and the dynamics of the individual velocities, thus obtaining a new model of collective motion. In the appropriate overdamped limit we recover the well-known Vicsek model, which dissipates rotational information and does not allow for polarized turns. Although the new model has its most vivid success in describing turning groups, its dynamics is intrinsically different from previous ones in a wide dynamical regime, while reducing to the hydrodynamic description of Toner and Tu at very large length-scales. The derived framework is therefore general and it may describe the collective motion of any strongly polarized active matter system

Musculoskeletal pain is associated with very low levels of vitamin D in men: results from the European Male Ageing Study

Introduction: a study was undertaken to test the hypothesis that musculoskeletal pain is associated with low vitamin D levels but the relationship is explained by physical inactivity and/or other putative confounding factors.Methods: men aged 40–79 years completed a postal questionnaire including a pain assessment and attended a clinical assessment (lifestyle questionnaire, physical performance tests, 25-hydroxyvitamin D3 (25-(OH)D) levels from fasting blood sample). Subjects were classified according to 25-(OH)D levels as ‘normal’ (≥15 ng/ml) or ‘low’ (<15 ng/ml). The relationship between pain status and 25-(OH)D levels was assessed using logistic regression. Results are expressed as ORs and 95% CIs.Results: 3075 men of mean (SD) age 60 (11) years were included in the analysis. 1262 (41.0%) subjects were pain-free, 1550 (50.4%) reported ‘other pain’ that did not satisfy criteria for chronic widespread pain (CWP) and 263 (8.6%) reported CWP. Compared with patients who were pain-free, those with ‘other pain’ and CWP had lower 25-(OH)D levels (n=239 (18.9%), n=361 (23.3) and n=67 (24.1%), respectively, p<0.05). After adjusting for age, having ‘other pain’ was associated with a 30% increase in the odds of having low 25-(OH)D while CWP was associated with a 50% increase. These relationships persisted after adjusting for physical activity levels. Adjusting for additional lifestyle factors (body mass index, smoking and alcohol use) and depression attenuated these relationships, although pain remained moderately associated with increased odds of 20% of having low vitamin D levels.Conclusions: these findings have implications at a population level for the long-term health of individuals with musculoskeletal pain