Automated detection of impulsive movements in HCI

This paper introduces an algorithm for automatically measuring impulsivity. This can be used as a major expressive movement feature in the development of systems for realtime analysis of emotion expression from human full-body movement, a research area which has received increased attention in the affective computing community. In particular, our algorithm is developed in the framework of the EUH2020- ICT Project DANCE aiming at investigating techniques for sensory substitution in blind people, in order to enable perception of and participation in non-verbal, artistic whole-body experiences. The algorithm was tested by applying it to a reference archive of short dance performances. The archive includes a collection of both impulsive and fluid movements. Results show that our algorithm can reliably distinguish impulsive vs. sudden performances

Formation and Alteration of Basaltic Soils on Mars

The current surface of Mars is an arid inhospitable environment, dominated by aeolian processes, composed of largely volcanic rocks that have little apparent indication of pervasive aqueous chemical weathering, and blanketed by dust. Rocks are composed of basalts and the “soil” sediments appear to be largely basaltic-derived, and are chemically similar on a global scale. If the climate was once warmer and wetter during the Noachian period, with environmental conditions favorable to the development of life, physically weathered remnants, such as large quantities of phyllosilicate minerals, should remain. Basaltic soils provide a crucial constraint on chemical and physical weathering processes, and are critical for determining the environmental and climatic history of Mars. To understand the origin of sediments, this dissertation investigated the (1) textures of sedimentary grains at Gusev Crater, (2) the chemical and mineral compositions of sediments at the Mars Exploration Rover landing sites in Meridiani Planum and Gusev Crater, and evaluated the potential chemical alteration from weathering, and (3) applied mineral fractionation experiments of analog basalt sediment with implications for interpreting the sorting of sediments on Mars. Textural results indicate that soils are continuously transported and modified by aeolian conditions, and originate primarily from comminuted impacted bedrock. Soil chemical compositions resemble unaltered basalt but mixing of sulfates and phyllosilicates is permissible. Comminuted and grain size sorted basalt analog sediments demonstrate the potential for significant compositional variations imposed by hydrodynamic sorting, an important determinant of soil compositions on Mars. Combined, these results show that soils on Mars are heterogeneous mixtures of comminuted locally derived rocks that have been minimally altered by chemical weathering from olivine dissolution, and are mixed with dust containing older phyllosilicates and sulfates

Statistical Modeling of SAR Images: A Survey

Statistical modeling is essential to SAR (Synthetic Aperture Radar) image interpretation. It aims to describe SAR images through statistical methods and reveal the characteristics of these images. Moreover, statistical modeling can provide a technical support for a comprehensive understanding of terrain scattering mechanism, which helps to develop algorithms for effective image interpretation and creditable image simulation. Numerous statistical models have been developed to describe SAR image data, and the purpose of this paper is to categorize and evaluate these models. We first summarize the development history and the current researching state of statistical modeling, then different SAR image models developed from the product model are mainly discussed in detail. Relevant issues are also discussed. Several promising directions for future research are concluded at last

The geology, sedimentology, geochronology and palaeo-environmental reconstruction of the Heelbo hillslope deposit, Free State Province, South Africa

Thesis submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy University of the Witwatersrand South Africa 2015A multidisciplinary sedimentological, stratigraphic, mineralogical and geochronological analysis of a small, fossil-bearing, Holocene hillslope deposit, flanking a mesa, has enabled a reconstruction of the palaeo-environmental history of the region. The hillslope deposit, located on the farm Heelbo in the eastern Free State Povince, South Africa, overlies Jurassic mudrock and sandstone of the Elliot Formation, Karoo Supergroup. The deposit is located on a steep (~10°) slope and covers an area of ~7 km2 in two separate sections. It extends ~475 m downslope and reaches a maximum thickness of at least 6-8 m towards the base. Mineralogy indicates the deposit is sourced from the mesa but its fine grain size and location on a steep slope position Heelbo outside the scope of traditionally described alluvial fans or colluvial deposits. The hillslope deposit is described as an alluvial slope based on the morphology of the deposit and the grain size distribution against the slope gradient. The deposit comprises fine-sand to silt- grain size, but is found on a steep (~10°) slope. The source of the sediment is shown to be the sediment of the mesa, rather than input from an aeolian source. The grains are described as sub-angular and poorly sorted which also suggests a local provenance for the sediment. Microscopic and XRF analysis confirm the derivation of the sediment from the Elliot Formation, with the lithic fragments derived from subarkoses to arkoses of the underlying bedrock of the Upper Elliot Formation (UEF) in the Karoo Supergroup. Secondary calcite was visible in only two of the thin sections, thus it is likely due to a diagenetic overprint that is constrained by depth from the surface or time and not to specific layers. The deposit is cut by several mature and continuous gully networks with V-shaped profiles in the proximal slope, and combined V- and U-shaped profiles in the medial and distal sections. Gully formation is linked to both the sodium adsorption ratio (SARs), and high soil clay content, which facilitates swelling and shrinking. The Heelbo deposit comprises two palaeosols (BT1 and BT2) and four sediment (B1, B2, RB and TS) horizons. Through luminescence dating, the ages were found to be approximately 6390 ± 740 years BP for the oldest Brown (B1) horizon and 250 ± 170 years BP for the Red Brown (RB) horizon. The radiocarbon ages of the sediment were inconclusive, but the 14C ages of the fossil bones were in agreement with the luminescence ages. The multiple palaeosol horizons identified suggest two cycles of deposition, pedogenesis and erosion of the alluvial succession. The palaeosols and the presence of calcareous nodules and rhizocretions, and smectite and mixed-layer clay minerals, together with the total absence of illite and kaolinite, suggest protracted, dry periods with intermittent short periods of high rainfall. This is a similar climate regime to what the region experiences currently. Main findings: The Heelbo alluvial slope comprises locally derived sediment, rather than an aeolian source. Heelbo suggests that the hillslope deposits classification system needs to be re-evaluated and opens opportunities for wider study of Pleistocene-Holocene hillslope deposits in central / northern South Africa. This study also contributes to climate change debates in the Holocene

The geology, sedimentology, geochronology and palaeo-environmental reconstruction of the Heelbo hillslope deposit, Free State Province, South Africa

Thesis submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy University of the Witwatersrand South Africa 2015A multidisciplinary sedimentological, stratigraphic, mineralogical and geochronological analysis of a small, fossil-bearing, Holocene hillslope deposit, flanking a mesa, has enabled a reconstruction of the palaeo-environmental history of the region. The hillslope deposit, located on the farm Heelbo in the eastern Free State Povince, South Africa, overlies Jurassic mudrock and sandstone of the Elliot Formation, Karoo Supergroup. The deposit is located on a steep (~10°) slope and covers an area of ~7 km2 in two separate sections. It extends ~475 m downslope and reaches a maximum thickness of at least 6-8 m towards the base. Mineralogy indicates the deposit is sourced from the mesa but its fine grain size and location on a steep slope position Heelbo outside the scope of traditionally described alluvial fans or colluvial deposits. The hillslope deposit is described as an alluvial slope based on the morphology of the deposit and the grain size distribution against the slope gradient. The deposit comprises fine-sand to silt- grain size, but is found on a steep (~10°) slope. The source of the sediment is shown to be the sediment of the mesa, rather than input from an aeolian source. The grains are described as sub-angular and poorly sorted which also suggests a local provenance for the sediment. Microscopic and XRF analysis confirm the derivation of the sediment from the Elliot Formation, with the lithic fragments derived from subarkoses to arkoses of the underlying bedrock of the Upper Elliot Formation (UEF) in the Karoo Supergroup. Secondary calcite was visible in only two of the thin sections, thus it is likely due to a diagenetic overprint that is constrained by depth from the surface or time and not to specific layers. The deposit is cut by several mature and continuous gully networks with V-shaped profiles in the proximal slope, and combined V- and U-shaped profiles in the medial and distal sections. Gully formation is linked to both the sodium adsorption ratio (SARs), and high soil clay content, which facilitates swelling and shrinking. The Heelbo deposit comprises two palaeosols (BT1 and BT2) and four sediment (B1, B2, RB and TS) horizons. Through luminescence dating, the ages were found to be approximately 6390 ± 740 years BP for the oldest Brown (B1) horizon and 250 ± 170 years BP for the Red Brown (RB) horizon. The radiocarbon ages of the sediment were inconclusive, but the 14C ages of the fossil bones were in agreement with the luminescence ages. The multiple palaeosol horizons identified suggest two cycles of deposition, pedogenesis and erosion of the alluvial succession. The palaeosols and the presence of calcareous nodules and rhizocretions, and smectite and mixed-layer clay minerals, together with the total absence of illite and kaolinite, suggest protracted, dry periods with intermittent short periods of high rainfall. This is a similar climate regime to what the region experiences currently. Main findings: The Heelbo alluvial slope comprises locally derived sediment, rather than an aeolian source. Heelbo suggests that the hillslope deposits classification system needs to be re-evaluated and opens opportunities for wider study of Pleistocene-Holocene hillslope deposits in central / northern South Africa. This study also contributes to climate change debates in the Holocene

Age-related delay in information accrual for faces: Evidence from a parametric, single-trial EEG approach

Background: In this study, we quantified age-related changes in the time-course of face processing by means of an innovative single-trial ERP approach. Unlike analyses used in previous studies, our approach does not rely on peak measurements and can provide a more sensitive measure of processing delays. Young and old adults (mean ages 22 and 70 years) performed a non-speeded discrimination task between two faces. The phase spectrum of these faces was manipulated parametrically to create pictures that ranged between pure noise (0% phase information) and the undistorted signal (100% phase information), with five intermediate steps. Results: Behavioural 75% correct thresholds were on average lower, and maximum accuracy was higher, in younger than older observers. ERPs from each subject were entered into a single-trial general linear regression model to identify variations in neural activity statistically associated with changes in image structure. The earliest age-related ERP differences occurred in the time window of the N170. Older observers had a significantly stronger N170 in response to noise, but this age difference decreased with increasing phase information. Overall, manipulating image phase information had a greater effect on ERPs from younger observers, which was quantified using a hierarchical modelling approach. Importantly, visual activity was modulated by the same stimulus parameters in younger and older subjects. The fit of the model, indexed by R2, was computed at multiple post-stimulus time points. The time-course of the R2 function showed a significantly slower processing in older observers starting around 120 ms after stimulus onset. This age-related delay increased over time to reach a maximum around 190 ms, at which latency younger observers had around 50 ms time lead over older observers. Conclusion: Using a component-free ERP analysis that provides a precise timing of the visual system sensitivity to image structure, the current study demonstrates that older observers accumulate face information more slowly than younger subjects. Additionally, the N170 appears to be less face-sensitive in older observers

Modelling fruit and vegetable consumption : a comparative study of two cities with high and low consumption

The importance of the consumption of a diet rich in fruit and vegetables, for overall health, has been highlighted by the UK government in recent years. Consumption of fruit and vegetables is considerably lower in Scotland than in other parts of the UK. Behavioural change is most likely to come about through a comprehensive understanding of the range of factors influencing fruit and vegetable consumption, and the nature of the interaction of these factors. With variations in fruit and vegetable consumption by place and social class, this study focused on an area of low fruit and vegetable consumption in Scotland, and compared this to an area of high fruit and vegetable consumption in England, with socio-economic profile matched. The determinants of consumption, and their interrelationship, were investigated using qualitative information from focus group discussions, and quantitative data from a structured questionnaire. Multivariate models of fruit and vegetables consumption were developed, using log linear analysis, logistic regression and discriminant analysis. The models developed identified significant differences between fruit and vegetable consumption behaviour. Fruit consumption was mainly influenced by sociodemographic variables,in particulars mokers tatus. The impact of place and social class was substantial, when these variables were considered in interaction with the other socio-demographic variables. In contrast, vegetable consumption was influenced by motivational and attitudinal factors. Of these, the extent to which vegetables satisfied `convenience' expectations, and `hedonic motivations' were the most important influences, critical to vegetable consumption. The findings also suggest that the development of a generic model of food choice may not be an achievable goal, since the models of these two (similar) foodstuffs are so different. Strategies to promote fruit and vegetable consumption, must address the different characteristics, and priorities, of low fruit and vegetable consumers