Proof explanation for a nonmonotonic Semantic Web rules language

In this work, we present the design and implementation of a system for proof explanation in the Semantic Web, based on defeasible reasoning. Trust is a vital feature for Semantic Web. If users (humans and agents) are to use and integrate system answers, they must trust them. Thus, systems should be able to explain their actions, sources, and beliefs. Our system produces automatically proof explanations using a popular logic programming system (XSB), by interpreting the output from the proof’s trace and converting it into a meaningful representation. It also supports an XML representation for agent communication, which is a common scenario in the Semantic Web. In this paper, we present the design and implementation of the system, a RuleML language extension for the representation of a proof explanation, and we give some examples of the system. The system in essence implements a proof layer for nonmonotonic rules on the Semantic Web.     

Uniaxial deformation of an elastomer nanocomposite containing modified carbon nanofibers by in situ synchrotron X-ray diffraction

Structure and property of a nanocomposite consisting of modified carbon nanofibers (MCNFs), homogenously dispersed in an elastomeric ethylene/propylene (EP) random copolymer (84.3 wt% P) matrix, were studied by in situ synchrotron X-ray diffraction during uniaxial deformation. The MCNF acted as a nucleating agent for crystallization of the α-form of isotactic polypropylene (iPP) in the matrix. During deformation at room temperature, strain-induced crystallization took place, while the transformation from the γ phase to α phase also occurred for both unfilled and 10 wt% MCNF-filled samples. The tensile strength of the filled material was consistently higher than that of pure copolymer. However, when compared with pure copolymer, the highly stretched nanocomposite exhibited a higher amount of unoriented crystals, a lower degree of crystal orientation and a higher amount of γ crystals. This behavior indicated that polymer crystals in the filled nanocomposite experienced a reduced load, suggesting an effective load transfer from the matrix to MCNFs. At elevated temperatures, the presence of MCNFs resulted in a thermally stable physically cross-linked network, which facilitated strain-induced crystallization and led to a remarkable improvement in the mechanical properties. For example, the toughness of the 10 wt% nanocomposite was found to increase by a factor of 150 times at 55 °C.     

Virtual social interactions: Evolutionary, social psychological and technological perspectives

This paper represents an exploratory and quantitative investigation into online dating from evolutionary, psychological, and technological points of view. In the past decade, the relatively inexpensive availability of user-friendly, fast, and reliable Internet technology has appealed to millions of consumers who suddenly found themselves engrossed by this sensational medium of communication, information, consumerism, and service. The majority of Internet users tend to be either recreational or utilitarian oriented, using such medium for a wide variety of tasks ranging from corresponding with friends and significant others, information gathering, purchasing goods and services, and, increasingly so, seeking and securing suitable dating and marital partners. The following research questions constitute the driving force for the current investigation: What are the evolutionary and social psychological intricacies of online dating? What are the technological variants or dimensions that render the consumption of online dating services appealing to users? An online survey was administered to 247 subjects to explore these questions and determine the technological dimensions of virtual social interaction. Exploratory factor analysis was then conducted to analyse the data. Eight technological dimensions emerged as a result of the analysis and served as the basis for the study’s technological perspectives model of virtual social interactions.     

Statistical accuracy of a moving equivalent dipole method to identify sites of origin of cardiac electrical activation

While radio frequency (RF) catheter ablation (RCA) procedures for treating ventricular arrhythmias have evolved significantly over the past several years, the use of RCA has been limited to treating slow ventricular tachycardias (VTs). In this paper, we present preliminary results from computer and animal studies to evaluate the accuracy of an algorithm that uses the single equivalent moving dipole (SEMD) model in an infinite homogeneous volume conductor to guide the RF catheter to the site of origin of the arrhythmia. Our method involves measuring body surface electrocardiographic (ECG) signals generated by arrhythmic activity and by bipolar current pulses emanating from a catheter tip, and representing each of them by a SEMD model source at each instant of the cardiac cycle, thus enabling rapid repositioning of the catheter tip requiring only a few cycles of the arrhythmia. We found that the SEMD model accurately reproduced body surface ECG signals with a correlation coefficients > 0.95. We used a variety of methods to estimate the uncertainty of the SEMD parameters due to measurement noise and found that at the time when the arrhythmia is mostly localized during the cardiac cycle, the estimates of the uncertainty of the spatial SEMD parameters (from ECG signals) are between 1 and 3 mm. We used pacing data from spatially separated epicardial sites in a swine model as surrogates for focal ventricular arrhythmic sources and found that the spatial SEMD estimates of the two pacing sites agreed with both their physical separation and orientation with respect to each other. In conclusion, our algorithm to estimate the SEMD parameters from body surface ECG can potentially be a useful method for rapidly positioning the catheter tip to the arrhythmic focus during an RCA procedure.     

Automated techniques in serum lipid analysis

Semi- and partially-automated procedures for the analysis of serum lipids directly on the initial solvent extract which have been developed recently by the author and other investigators are reviewed. Techniques are discussed which involve either colorimetric or fluorimetric estimation of the concentration of the individual lipid components of serum such as total cholesterol, acyl esters, phospholipids, triglycerides and free fatty acids. The results obtained with the automated methods are presented and evaluated by comparison to established manual methods now routinely used in clinical laboratories, and the advantage as well as the limitations of the automated procedures are indicated. Presented at the Symposium, “Automation in Lipid Research,” AOCS Meeting, Los Angeles, April 1966.     

An investigation of the economic perspective in modeling occupational risk

The existing approaches to modeling occupational risk assume that the goals of the enterprise and the worker are identical and that they are served through a mutually optimal performance level. This paper aims to challenge this assumption and indicate the implications in the absence of it. This discussion is conducted by focusing on the economic perspective through the application of utility analysis in workplace risk. Different cases of employment status are examined with special reference to rational and biased decision‐making under uncertainty. This analysis does not offer a new alternative to risk modeling on its own, but it can offer some important insight into this process. © 2010 Wiley Periodicals, Inc.     

Feed-in tariffs for promotion of energy storage technologies

Faster market integration of new energy technologies can be achieved by use of proper support mechanisms that will create favourable market conditions for such technologies. The best examples of support mechanisms presented in the last two decades have been the various schemes for the promotion of renewable energy sources (RES). In the EU, the most successful supporting schemes are feed-in tariffs which have significantly increased utilisation of renewable energy sources in Germany, Spain, Portugal, Denmark and many other EU countries. Despite the successful feed-in tariffs for RES promotion, in many cases RES penetration is limited by power system requirements linked to the intermittency of RES sources and technical capabilities of grids. These problems can be solved by implementation of energy storage technologies like reversible or pumped hydro, hydrogen, batteries or any other technology that can be used for balancing or dump load. In this paper, feed-in tariffs for various energy storage technologies are discussed along with a proposal for their application in more appropriate regions. After successful application on islands and outermost regions, energy storage tariffs should be also applied in mainland power systems. Increased use of energy storage could optimise existing assets on the market.     

Food-packaging migration models: A critical discussion

ABSTRACT

The widely accepted and used migration models that describe the mass transport from polymeric packaging material to food and food simulants are confirmed here. A critical review of the most accepted models is presented in detail. Their main advantages and weak points, regarding their predictive accuracy, are discussed and weighted toward their usage extensiveness. By identifying the specific areas where using such models may not provide a strong correlation between theoretical and actual results, this work also aims in outlining some particular directions regarding further research on food – packaging interactions.