196 research outputs found

    New Predicted Spiral Search Block Matching Algorithm - PSSBMA

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    This article describes the modification of the full search algorithm ESBMA (Exhaustive Search Block Matching Algorithm), which leads up to 40% speed increase. The modification is based on the ESBMA motion field analysis results. The major modifications to the ESBMA are: - Introduction of sub-optimality by thresholding the matching criterion (MAEthr); - Respecting constraints on motion vectors resulting from "head and shoulder" scenes by changing the position of the search start; - Respecting the dependence of motion vectors (MV) by prediction introduction

    Teaching the principle of conservation of Mechanical Energy using a conceptual change approach

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    Magister Educationis - MedThe purpose of this study was to investigate the effect of the conceptual-change teaching strategy on the Principle of Conservation of Mechanical Energy in the absence of dissipative forces. Specifically, the study used the scientific investigation and interactive simulations in the teaching of the Principle of Conservation of Mechanical Energy concepts. The research design adopted for the study was a case study in which a mixed method approach was used. A sample of thirty learners was purposively selected from a grade 10 Physical Sciences class in the rural Eastern Cape. Data were collected using the pre-test, concept map and semi-structured interviews. The pre-test and the concept map were systematically assessed for validity and reliability by involving experts in Science Education and through pilot study. Mean, standard deviation and thematic analysis were employed in the analysis of data. The quantitative results indicated that learners who held to their alternative conceptions hinder their learning and understanding of scientific concepts. Results also indicated a significant improvement in the learners' understanding of the energy concept and its conservation after the use of the conceptual change strategy. The qualitative results indicated that learners learn better through the conceptual change approach as learners are actively involved in restructuring their conceptual framework and the knowledge gained becomes more meaningful. Learners find the conceptual change approach effective as it is motivational and engages them in dialogues and debates that iron out grey areas. Based on these findings the study recommends that teachers should endeavour to incorporate the conceptual change model as one of the teaching approaches to be adopted in schools since it increases the learners' interest and learning in Science, especially in Physic

    Direct observation of the band gap transition in atomically thin ReS2_2

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    ReS2_2 is considered as a promising candidate for novel electronic and sensor applications. The low crystal symmetry of the van der Waals compound ReS2_2 leads to a highly anisotropic optical, vibrational, and transport behavior. However, the details of the electronic band structure of this fascinating material are still largely unexplored. We present a momentum-resolved study of the electronic structure of monolayer, bilayer, and bulk ReS2_2 using k-space photoemission microscopy in combination with first-principles calculations. We demonstrate that the valence electrons in bulk ReS2_2 are - contrary to assumptions in recent literature - significantly delocalized across the van der Waals gap. Furthermore, we directly observe the evolution of the valence band dispersion as a function of the number of layers, revealing a significantly increased effective electron mass in single-layer crystals. We also find that only bilayer ReS2_2 has a direct band gap. Our results establish bilayer ReS2_2 as a advantageous building block for two-dimensional devices and van der Waals heterostructures

    Pointing to visible and invisible targets

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    We investigated how the visibility of targets influenced the type of point used to provide directions. In Study 1 we asked 605 passersby in three localities for directions to well-known local landmarks. When that landmark was in plain view behind the requester, most respondents pointed with their index fingers, and few respondents pointed more than once. In contrast, when the landmark was not in view, respondents pointed initially with their index fingers, but often elaborated with a whole-hand point. In Study 2, we covertly filmed the responses from 157 passersby we approached for directions, capturing both verbal and gestural responses. As in Study 1, few respondents produced more than one gesture when the target was in plain view and initial points were most likely to be index finger points. Thus, in a Western geographical context in which pointing with the index finger is the dominant form of pointing, a slight change in circumstances elicited a preference for pointing with the whole hand when it was the second or third manual gesture in a sequence

    Wedge resection versus lobectomy in T1 lung cancer patients: a propensity matched analysis

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    Objectives: Performing wedge resection rather than lobectomy for primary lung cancer remains controversial. Recent studies demonstrate no survival advantage for non-anatomical resection compared to lobectomy in patients with early-stage lung cancer. The objective of this study was to investigate whether in patients with T1 tumours, non-anatomical wedge resection is associated with equivalent survival to lobectomy. Methods: This was a retrospective cohort study of patients who underwent lung resection at the Lancashire Cardiac Centre between April 2005 and April 2018. Patients were subjected to multidisciplinary team discussion. The extent of resection was decided by the team based on British Thoracic Society guidelines. The primary outcome was overall survival. Propensity matching of patients with T1 tumours was also performed to determine whether differences in survival rates exist in a subset of these patients with balanced pre-operative characteristics. Results: There were 187 patients who underwent non-anatomical wedge resection and 431 patients who underwent lobectomy. Cox modelling demonstrated no survival difference between groups for the first 1.6 years then a risk of death 3-fold higher for wedge resection group after 1.6 years (HR 3.14, CI 1.98–4.79). Propensity matching yielded 152 pairs for which 5-year survival was 66.2% for the lobectomy group and 38.5% for the non-anatomical wedge group (SMD = 0.58, p = 0.003). Conclusions: Non-anatomical wedge resection was associated with significantly reduced 5-year survival compared to lobectomy in matched patients. Lobectomy should remain the standard of care for patients with early-stage lung cancer who are fit enough to undergo surgical resection

    Gestural communication of the gorilla (Gorilla gorilla): repertoire, intentionality and possible origins

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    Social groups of gorillas were observed in three captive facilities and one African field site. Cases of potential gesture use, totalling 9,540, were filtered by strict criteria for intentionality, giving a corpus of 5,250 instances of intentional gesture use. This indicated a repertoire of 102 gesture types. Most repertoire differences between individuals and sites were explicable as a consequence of environmental affordances and sampling effects: overall gesture frequency was a good predictor of universality of occurrence. Only one gesture was idiosyncratic to a single individual, and was given only to humans. Indications of cultural learning were few, though not absent. Six gestures appeared to be traditions within single social groups, but overall concordance in repertoires was almost as high between as within social groups. No support was found for the ontogenetic ritualization hypothesis as the chief means of acquisition of gestures. Many gestures whose form ruled out such an origin, i.e. gestures derived from species-typical displays, were used as intentionally and almost as flexibly as gestures whose form was consistent with learning by ritualization. When using both classes of gesture, gorillas paid specific attention to the attentional state of their audience. Thus, it would be unwarranted to divide ape gestural repertoires into ‘innate, species-typical, inflexible reactions’ and ‘individually learned, intentional, flexible communication’. We conclude that gorilla gestural communication is based on a species-typical repertoire, like those of most other mammalian species but very much larger. Gorilla gestures are not, however, inflexible signals but are employed for intentional communication to specific individuals

    Predictive Process Monitoring Methods: Which One Suits Me Best?

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    Predictive process monitoring has recently gained traction in academia and is maturing also in companies. However, with the growing body of research, it might be daunting for companies to navigate in this domain in order to find, provided certain data, what can be predicted and what methods to use. The main objective of this paper is developing a value-driven framework for classifying existing work on predictive process monitoring. This objective is achieved by systematically identifying, categorizing, and analyzing existing approaches for predictive process monitoring. The review is then used to develop a value-driven framework that can support organizations to navigate in the predictive process monitoring field and help them to find value and exploit the opportunities enabled by these analysis techniques

    Inland Waters Increasingly Produce and Emit Nitrous Oxide

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    Nitrous oxide (N 2O) is a long-lived greenhouse gas and currently contributes ∼10% to global greenhouse warming. Studies have suggested that inland waters are a large and growing global N 2O source, but whether, how, where, when, and why inland-water N 2O emissions changed in the Anthropocene remains unclear. Here, we quantify global N 2O formation, transport, and emission along the aquatic continuum and their changes using a spatially explicit, mechanistic, coupled biogeochemistry-hydrology model. The global inland-water N 2O emission increased from 0.4 to 1.3 Tg N yr -1 during 1900-2010 due to (1) growing N 2O inputs mainly from groundwater and (2) increased inland-water N 2O production, largely in reservoirs. Inland waters currently contribute 7 (5-10)% to global total N 2O emissions. The highest inland-water N 2O emissions are typically in and downstream of reservoirs and areas with high population density and intensive agricultural activities in eastern and southern Asia, southeastern North America, and Europe. The expected continuing excessive use of nutrients, dam construction, and development of suboxic conditions in aging reservoirs imply persisting high inland-water N 2O emissions
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