Robust Visual Servoing of Robot Manipulators with Neuro Compensation

This paper considers the problem of visual servoing of planar robot manipulators in the presence of uncertainty associated with robot dynamics, camera system and Jacobian matrix. By using radial basis function neural networks, these uncertainties can be compensated effectively. Two kinds of robust visual servoing are proposed, one is for image uncertainties, another is for Jacobian matrix uncertainty. By Lyapunov method and input-to-state stability technique, we prove that these robust controllers with neural compensators are stable. Real-time experiments are presented to show the applicability of the approach presented in this paper.     

Assistant principals in high-stakes accountability environments: The effects of job attributes and school characteristics

This study addressed the topic of job specifications and school characteristics since there is a shortage of quality AP applicants in high-stakes accountability environments. It is important to learn about allocation of duties from educational administrators with on-the-job experience as well as to learn why current APs would consider applying for other AP positions. The purpose of this study was to investigate the impact of job attributes (instruction, discipline), school level (elementary, middle, high), and school achievement (in-need-of-assistance, progressing, meets goal) on applicant’s rating of an AP position. This research study used an experimental design. A main effect for job attributes indicated that instruction was significantly higher than discipline when attracting assistant principals. Implications for practice and research are discussed.     

The skill bias effect of technological and organisational change: Evidence and policy implications

Previous studies have suggested that technological change is the main cause of the recent increase in demand for highly skilled workers in developed countries. However, a more recent strand of literature has also introduced the “Skill Biased Organisational Change” hypothesis, according to which the increasing diffusion of new organisational practices within firms plays a role in the increasing demand for skilled workers. We estimate a SUR model for a sample of 400 Italian manufacturing firms, showing that upskilling is more a function of reorganisational strategy than a consequence of technological change alone. Moreover, some evidence of superadditive effects emerges, which is consistent with the notion that technology and organisation jointly affect the demand for labour.     

What determines technological hits?: Geography versus firm competencies

The centrality of firms vis-à-vis regions underlines a general contrast between two models of producing innovations. This paper uses a new database composed of 4262 European chemical patents applied by 693 firms during 1987–1996 to compare the relative effect of firm and regional characteristics on the production of technological “hits” (highly cited patents). By using extensive controls, the main finding of the paper is that technological hits in the “traditional” chemical sectors are explained only by R&D intensity at the firm level and the scale of the research projects. Firm competencies, particularly technological specialisation, are still important in biotechnology. However, the distinct feature of the biotechnology model is that localised knowledge spillovers also matter.     

Organic-inorganic material for the consolidation of plaster

Organic-inorganic materials to be used as hydrophobic consolidants for plasters were synthesized starting from an inorganic precursor (Tetraethoxysilane [TEOS]), added to a polysiloxane epoxy formulation and thermally cured with Ytterbium as acid catalyst. The TEOS reduces the viscosity of the resin, contributing to the mechanical properties of the film, without causing cracking. Solvents, that are harmful for workers and environment and show some drawbacks in the practice of restoration, were not used. The film properties and the formation of silica clusters were investigated. The products were applied by brush on plaster's samples and their compatibility and effectiveness were verified. Thanks to the organic content, the products penetrate deeply, are more stable to photo-oxidative degradation, and the hydrophobicity of the resin, provided by the silicone component, is not altered.     

Noninvasive physicochemical characterization of two 19th century English ferrotypes

The present work was one of the first attempts to analyze the conservation status of two ferrotypes, ancient photographic plates realized on a support made of iron. The photographic material was constituted of collodion as binder for the photosensitive silver halides grains. The two ferrotypes studied belonged to a private collection of a family from Durham, UK, and were made at the end of the 19th century. The analytical techniques used for the morphological and physicochemical characterization were noninvasive. The surface morphology was studied by means of optical microscopy (OM) and environmental scanning electron microscopy (ESEM) coupled with an energy dispersive X-rays (EDX) system for the elemental analysis. These techniques, together with microreflectance Fourier transform infrared spectroscopy (μ-FTIR) and contact angle, allowed to obtain information on both the chemical – elemental – composition of the materials constituting the ferrotypes, and the conservation status of these photographic plates. The study showed that the physicochemical diagnostics allowed to characterize the two ferrotypes that, despite their similar age and provenance, showed different conservation status, surface properties, and elemental composition.     

Effectiveness of pedalling retraining in reducing bilateral pedal force asymmetries

ABSTRACT

Previous studies have been limited to describe asymmetries during pedalling and suggest possible repercussion on performance and/or injury risks. However, few studies have presented strategies to mitigate asymmetries. The purpose of this study was to assess the effectiveness of a pedalling retraining intervention to reduce bilateral pedal force asymmetries. Twenty cyclists were assessed and 10 enrolled in a pedalling retraining method receiving visual and verbal feedback of pedal forces. The asymmetry index was computed for comparison of bilateral peak pedal forces and used during retraining (12 trials at 70% of peak power). Significantly larger asymmetry was observed for asymmetrical cyclists at the first three trials (P < 0.01 and ES = 1.39), which was reduced when post-retraining was compared to measures from symmetrical cyclists (P = 0.69 and ES = 0.18). Cyclists with larger asymmetry (>20%) in bilateral pedal forces reduce their asymmetries using sessions of pedalling retraining and achieve asymmetry indices similar to symmetrical cyclists.     

Self-citations as strategic response to the use of metrics for career decisions

There is limited knowledge on the extent to which scientists may strategically respond to metrics by adopting questionable practices, namely practices that challenge the scientific ethos, and the individual and contextual factors that affect their likelihood. This article aims to fill these gaps by studying the opportunistic use of self-citations, i.e. citations of one’s own work to boost metric scores. Based on sociological and economic literature exploring the factors driving scientists’ behaviour, we develop hypotheses on the predictors of strategic increase in self-citations. We test the hypotheses in the Italian Higher Education system, where promotion to professorial positions is regulated by a national habilitation procedure that considers the number of publications and citations received. The sample includes 886 scientists from four of science’s main disciplinary sectors, employs different metrics approaches, and covers an observation period beginning in 2002 and ending in 2014. We find that the introduction of a regulation that links the possibility of career advancement to the number of citations received is related to a strong and significant increase in self-citations among scientists who can benefit the most from increasing citations, namely assistant professors, associate professors and relatively less cited scientists, and in particular among social scientists. Our findings suggest that while metrics are introduced to spur virtuous behaviours, when not properly designed they favour the usage of questionable practices.     

Contingent Valuation of a Cultural Public Good and Policy Design: The Case of ``Napoli Musei Aperti'

The aim of the paper is twofold: to report on theapplication of a contingent valuation survey todetermine the value to the Naples population ofmaintaining ``Napoli Musei Aperti', a cultural publicgood provided by the city of Naples, and to exploresome alternative schemes of cultural policy. The paperis divided in two parts. The first presents someresults of the contingent valuation study. The seconddiscusses the use of the contingent valuation as apolicy instrument in the public cultural sector.