Accuracy between optical and inertial motion capture systems for assessing trunk speed during preferred gait and transition periods     

Martin Kokholm Fleron  Niels Christian Hauerbach Ubbesen  Francesco Battistella  David Leandro Dejtiar 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(4):366-377

Motion capture through inertial sensors is becoming popular, but its accuracy to describe kinematics during changes in walking speed is unknown. The aim of this study was to determine the accuracy of trunk speed extracted using an inertial motion system compared to a gold standard optical motion system, during steady walking and stationary periods. Eleven participants walked on pre-established paths marked on the floor. Between each lap, a 1-second stationary transition period at the initial position was included prior to the next lap. Resultant trunk speed during the walking and transition periods were extracted from an inertial (240 Hz sampling rate) and an optical system (120 Hz sampling rate) to calculate the agreement (Pearson’s correlation coefficient) and relative root mean square errors between both systems. The agreement for the resultant trunk speed between the inertial system and the optical system was strong (0.67 < r ≤ 0.9) for both walking and transition periods. Moreover, relative root mean square error during the transition periods was greater in comparison to the walking periods (>40% across all paths). It was concluded that trunk speed extracted from inertial systems have fair accuracy during walking, but the accuracy was reduced in the transition periods.  相似文献   

Protective action against fungal growth of two consolidating products applied to wood     

Marina Clausi  Gino Mirocle Crisci  Mauro Francesco La Russa  Marco Malagodi  Annamaria Palermo  Silvestro Antonio Ruffolo   《Journal of Cultural Heritage》2011,12(1):28-33

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Indirect estimation of injected mortar volume in historical walls using the electrical resistivity tomography     

Nasser Abu Zeid  Marco Balducci  Francesco Bartocci  Roberto Regni  Giovanni Santarato 《Journal of Cultural Heritage》2010,11(2):220-227

The electrical resistivity tomography (ERT) represents one of the widely used geophysical techniques for the exploration of the subsurface. In the last few years, this method has been demonstrated to be an efficient reconnaissance tool not only for monitoring degradation status of walls and foundations of historical buildings, but also for imaging the spatial distribution of injected mortar, commonly employed for consolidation purposes. A 3D resistivity tomography survey was carried out on four selected wall portions of the historical church of Montepetriolo, Perugia, Central Italy. The obtained 3D resistivity distribution models before and after grouting provided suggestive images of the internal structure of the studied walls. Moreover, the spatial distribution of the zones being filled with mortar was determined quantitatively by scaling the post- to the preinjection resistivity values. Using a well known correlation between resistivity and porosity, established in the geophysical community, a further step towards a more quantitative assessment was attempted to indirectly determine the unit volumes of the injected mortar The obtained results were satisfactory and in some cases almost similar to the yard data. Furthermore, two flat-jack tests confirmed the local increment of the mechanical resistance of the studied left front (2) and right lateral (3) wall portions.  相似文献   

How do socioeconomic attainment gaps in early mathematical ability arise?     

Ella James-Brabham  Toni Loveridge  Francesco Sella  Paul Wakeling  Daniel J. Carroll  Emma Blakey 《Child development》2023,94(6):1550-1565

Socioeconomic attainment gaps in mathematical ability are evident before children begin school, and widen over time. Little is known about why early attainment gaps emerge. Two cross-sectional correlational studies were conducted in 2018–2019 with socioeconomically diverse preschoolers, to explore four factors that might explain why attainment gaps arise: working memory, inhibitory control, verbal ability, and frequency of home mathematical activities (N = 304, 54% female; 84% White, 10% Asian, 1% black African, 1% Kurdish, 4% mixed ethnicity). Inhibitory control and verbal ability emerged as indirect factors in the relation between socioeconomic status and mathematical ability, but neither working memory nor home activities did. We discuss the implications this has for future research to understand, and work towards narrowing attainment gaps.  相似文献   

The Effects of Concreteness on Mathematical Manipulative Choice     

Megan Foulkes  Francesco Sella  Theresa Elise Wege  Camilla Gilmore 《Mind, Brain, and Education》2023,17(3):185-196

There is mixed evidence as to whether concrete manipulatives (e.g., toy animals) are better than abstract manipulatives (e.g., counters) for teaching mathematical concepts to children. Concreteness is defined as the amount of extraneous information a manipulative provides, and in this study we aimed to unpick which dimensions of concreteness influence manipulative choice. Researchers, teachers, and parents completed a comparative judgment task comparing images of manipulatives varying in different dimensions of concreteness, selecting which they would choose to teach arithmetic to children. The findings indicated homogeneous, 3-dimensional manipulatives were the most preferred across all groups to teach arithmetic to children, regardless of more extraneous features. This contradicts research recommendations to minimize the use of concrete manipulatives due to their distractive qualities. Instead, it suggests that some concrete features may be preferred in more naturalistic contexts. More research is required to investigate how different dimensions of concreteness influence learning outcomes for children both in artificial research contexts and in practice.  相似文献