Exploiting Resolution-based Representations for MaxSAT Solving

Most recent MaxSAT algorithms rely on a succession of calls to a SAT solver in order to find an optimal solution. In particular, several algorithms take advantage of the ability of SAT solvers to identify unsatisfiable subformulas. Usually, these MaxSAT algorithms perform better when small unsatisfiable subformulas are found early. However, this is not the case in many problem instances, since the whole formula is given to the SAT solver in each call. In this paper, we propose to partition the MaxSAT formula using a resolution-based graph representation. Partitions are then iteratively joined by using a proximity measure extracted from the graph representation of the formula. The algorithm ends when only one partition remains and the optimal solution is found. Experimental results show that this new approach further enhances a state of the art MaxSAT solver to optimally solve a larger set of industrial problem instances

Patterns of innovation diffusion and technological competition in Portuguese manufacturing and service industries

This article uses data from the Portuguese Community Innovation Survey (CIS III) to analyse the inter-industry heterogeneity in the diffusion of innovations and level of technological competition in Portuguese manufacturing and service industries. The industries are classified with reference to the relationship between the level of participation in innovation and the strategies of innovative firms. Methods of multivariate statistics are used to synthesize the data and to group the observations into subsets. Four distinctive innovation patterns are identified, defined along the following dimensions: output-orientation of innovation, importance of disembodied innovation, role of technologically advanced innovation and level of innovation opportunities. It is also found that high levels of technological competition tend to occur in sectors with relatively low dimension, productivity and overall investment

Modelling radiation emission in the transition from the classical to the quantum regime

An emissivity formula is derived using the generalised Fermi-Weizacker-Williams method of virtual photons which accounts for the recoil the charged particle experiences as it emits radiation. It is found that through this derivation the formula obtained by Sokolov et al using QED perturbation theory is recovered. The corrected emissivity formula is applied to nonlinear Thomson scattering scenarios in the transition from the classical to the quantum regime, for small values of the nonlinear quantum parameter \chi. Good agreement is found between this method and a QED probabilistic approach for scenarios where both are valid. In addition, signatures of the quantum corrections are identified and explored.Comment: 11 pages, 4 figures, submitted for publicatio

Regenerative braking potencial and energy simulations for a plug-in hybrid electric vehicle under real driving conditions

There are several possible configurations and technologies for the powertrains of electric and hybrid vehicles, but most of them will include advanced energy storage systems comprising batteries and ultra-capacitors. Thus, it will be of capital importance to evaluate the power and energy involved in braking and the fraction that has the possibility of being regenerated. The Series type Plug-in Hybrid Electric Vehicle (SPHEV), with electric traction and a small Internal Combustion Engine ICE) powering a generator, is likely to become a configuration winner. The first part of this work describes the model used for the quantification of the energy flows of a vehicle, following a particular route. Normalised driving-cycles used in Europe and USA and real routes and traffic conditions were tested. The results show that, in severe urban drivingcycles, the braking energy can represent more than 70% of the required useful motor-energy. This figure is reduced to 40% in suburban routes and to a much lower 18% on motorway conditions. The second part of the work consists on the integration of the main energy components of an S-PHEV into the mathematical model. Their performance and capacity characteristics are described and some simulation results presented. In the case of suburban driving, 90% of the electrical motor-energy is supplied by the battery and ultra-capacitors and 10% by the auxiliary ICE generator, while on motorway these we got 65% and 35%, respectively. The simulations also indicate an electric consumption of 120 W.h/km for a small 1 ton car on a suburban route. This value increases by 11% in the absence of ultra-capacitors and a further 28% without regenerative braking.Fundação para a Ciência e a Tecnologia (FCT) - MIT-Pt/EDAMSMS/0030/200

ANTHROPOMETRIC EVALUATION OF A UNIVERSITY LECTURE HALL’S SEAT

Ergonomics deals with the methods and processes of designing workplaces so that they fit the individuals that make use of them. This paper focuses on the anthropometric evaluation of the lecture hall’s seat of a University. Two anthropometric dimensions, the popliteal height (PH) and the buttock-popliteal length (BP) of 188 undergraduate students using the University lecture hall were taken. The lecture hall’s seat has height of 465mm and depth of 405mm. It was found that 61% of the student population used for the study was in the fit range of the seat height. Examining the seat depth and buttock to popliteal length, it was observed that 53.7% of the students may be comfortable using the present seat depth design of 405mm dimension, while over 46% of the students’ population used for the study might not be able to utilize the backrest of the seat. From this study, it was found that the seat depth of the University lecture hall’s seats were not adequate and a model should be developed to determine the most appropriate seat depth required for the University’s lecture hall’s seats. &nbsp