Nearest neighbor search in metric spaces through Content-Addressable Networks     

Fabrizio Falchi  Claudio Gennaro  Pavel Zezula 《Information processing & management》2008

Most of the Peer-to-Peer search techniques proposed in the recent years have focused on the single-key retrieval. However, similarity search in metric spaces represents an important paradigm for content-based retrieval in many applications. In this paper we introduce an extension of the well-known Content-Addressable Network paradigm to support storage and retrieval of more generic metric space objects. In particular we address the problem of executing the nearest neighbors queries, and propose three different algorithms of query execution. An extensive experimental study on real-life data sets explores the performance characteristics of the proposed algorithms by showing their advantages and disadvantages.  相似文献   

Mental Preparation Strategies of Olympic Archers During Competition: an exploratory investigation     

Claudio Robazza  Laura Bortoli 《High Ability Studies》1998,9(2):219-235

Extensive interviews were conducted with all eight members of the 1996 Italian Olympic archery team regarding psychological factors associated with excellence and mental preparation strategies adopted during competition. Hierarchical inductive analysis revealed that positive expectations, concentration, facilitating emotions, body awareness and technical preparation were the mental aspects described by archers necessary for effective performance. Furthermore, the archers outlined a variety of mental preparation strategies including (a) autonomic control (emotion control, somatic control, internal dialogue, and focus on shooting), (b) imagery (visualization, self‐talk), (c) task‐focused concentration (body and action control, thought control) and (d) reaction to mistake (focus on correct execution, mistake disregard, shooting analysis). The idiosyncratic nature of the athlete's competition strategies highlights the need of gaining information about the particular demands of the sport and the mental procedures spontaneously developed by the performer, to provide suitable counselling or psychological intervention.  相似文献   

A novel Cervical Spine Protection device for reducing neck injuries in contact sports: design concepts and preliminary in vivo testing*     

Paolo Caravaggi  Alberto Leardini  Claudio Belvedere 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(3):382-394

Abstract

Head and neck injuries are common in contact sports such as American football. Different mechanisms can produce such injuries, including compressive impact forces on the crown of the helmet with the neck in a flexed chin-down position. The aim of this paper was developing and testing a novel Cervical Spine Protection Device (CSPD) designed to keep the neck within its safe physiological range. The cervical spine range of motion (ROM) of ten participants was measured under four conditions: free; wearing a football gear; wearing the CSPD; and wearing the CSPD underneath the gear. The CSPD was tested in terms of passive and active restraint of head motion, and for its capability to improve endurance time of the neck extensor muscles. Wearing the CSPD resulted in a significant 40–60% reduction in ROM across the three anatomical planes, and in increased endurance of the neck extensor muscles (FREE: 114 ± 57 s; CSPD: 214 ± 95 s; p = 0.004). In quasi-static loading conditions the CSPD was capable of keeping the neck within its physiological range, thus it may be used to decrease the risk of severe injuries due to dangerous chin-down positions.  相似文献   

Measuring systematic long-term trajectories of school effectiveness improvement     

Juan Pablo Valenzuela  Cristián Bellei  Claudio Allende 《School Effectiveness & School Improvement》2016,27(4):473-491

The objective of this study was to identify trajectories of school improvement experienced by Chilean elementary schools over the last decade. Using econometric analysis and controlling for potential confounding factors, we created an index of school performance combining outcome indicators focused on different school dimensions, and estimated the 2002/2010 evolution of school improvement for all Chilean schools with available data. Broadly, we estimated an average increase in the school performance of about 0.19 SD; nevertheless, while 41% of the schools increased their educational performance by at least 0.1 SD, 25% of the schools decreased it during the same period; we also found that improving school effectiveness was more probable among schools with lower student socioeconomic status (SES). Finally, we found that the observed school improvement trajectories tended to be non-linear; thus, we estimated that only 13.4% of the schools improved their performance in a systematic way during the entire decade.  相似文献   

Changing students' attitudes towards risky motor tasks: an application of the IZOF model     

Robazza C  Bortoli L 《Journal of sports sciences》2005,23(10):1075-1088

The aim of this study was to evaluate the effectiveness of an intervention programme in the physical education setting designed to change attitudes and emotions triggered by potentially risky motor tasks. The individual zones of optimal functioning (IZOF) model was used as a theoretical framework for the study. Italian male and female high school students (N = 84) took part in a 12 lesson intervention and in test-retest sessions. The assessment was conducted using the Motor Activity Anxiety Test to measure the students' approach-avoidance attitudes in the face of physical education tasks purported to engender strong emotional reactions. An idiosyncratic emotional profile was also implemented using a list of pleasant/unpleasant emotional adjectives. Two experimental groups were involved in the learning and performing of several potentially risky, highly emotion-arousing tasks, while two control groups were engaged in low-risk team sports. According to the hypothesis of the study, the programme was effective in decreasing the students' avoidance tendencies towards thrilling tasks and in increasing optimal-pleasant emotions. Our findings also demonstrated the feasibility and utility of applying the IZOF model to the context of physical education.  相似文献   

History,Science and Culture: Curricular Experiences in Brazil     

Reis  José Claudio  Guerra  Andreia  Braga  Marco  Freitas  Jairo 《Science & Education》2001,10(4):369-378

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The building stones of the ancient centre of Naples (Italy): Piperno from Campi Flegrei. A contribution to the knowledge of a long-time-used stone     

Domenico Calcaterra  Piergiulio Cappelletti  Alessio Langella  Vincenzo Morra  Abner Colella  Roberto de Gennaro 《Journal of Cultural Heritage》2000,1(4)

Piperno, a Late Quaternary magmatic rock cropping out on the eastern side of the Campi Flegrei (Italy), is probably the most important building stone of Naples, used over a time-span from at least the Roman age until the beginning of the 20th century. Despite its wide diffusion in the monumental architecture of Naples, very little is known about this rock, as regards its technical features, as well as the geological aspects. This paper aims at providing a first overall contribution towards a rediscovery of this long-time-used material, in view of careful restoration works, which nowadays at Naples only take into account the proper geological features of the stone in a few peculiar cases. Thus, it seems of extreme importance to understand the basic parameters of Piperno and, above all, its response to weathering agents. Main mineralogical, petrographical and engineering–geological properties are presented here for the first time, with specific reference to two sampling areas, located at Pianura and Soccavo, in the western sector of the Neapolitan urban area. As far as many of its physico–mechanical features are concerned, Piperno extends over a wide range of values, which allow different varieties of the rock to be identified. This preliminary result is seemingly in accordance with data from old historical literature, which stated the existence of six horizons in the Piperno formation.  相似文献   

Why Sirtes's claims () do not square with reality     

Filippo Radicchi  Claudio Castellano 《Journal of Informetrics》2012,6(4):615-618

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Modelling Mechanical Wave Propagation: Guidelines and experimentation of a teaching–learning sequence     

Claudio Fazio  Ivan Guastella  Giovanni Tarantino 《International Journal of Science Education》2013,35(11):1491-1530

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Foresight for public procurement and regional innovation policy: The case of Lombardy     

Riccardo Vecchiato  Claudio Roveda 《Research Policy》2014

Public procurement can be a major source of innovation. The potential benefits of public procurement might be fully exploited through the acquisition not only of appliances which are already available in the market, but also of new appliances which are tailored to the specific needs of the local community and might be exported as well to the international markets. In this way, public procurement might allow to improve the services delivered to the local community and to increase the technological competitiveness of the local industrial and research system. In this context, regional foresight might help identify both long-term societal needs and the patterns of evolution of emerging technologies that can match these needs. The purpose of this paper is to illustrate, trough the recent experience of the regional government of Lombardy, the role of foresight for enhancing public procurement and innovation policy at the regional level.  相似文献