898 resultados para Video semantics


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Answer Set Programming (ASP) is a popular framework for modelling combinatorial problems. However, ASP cannot be used easily for reasoning about uncertain information. Possibilistic ASP (PASP) is an extension of ASP that combines possibilistic logic and ASP. In PASP a weight is associated with each rule, whereas this weight is interpreted as the certainty with which the conclusion can be established when the body is known to hold. As such, it allows us to model and reason about uncertain information in an intuitive way. In this paper we present new semantics for PASP in which rules are interpreted as constraints on possibility distributions. Special models of these constraints are then identified as possibilistic answer sets. In addition, since ASP is a special case of PASP in which all the rules are entirely certain, we obtain a new characterization of ASP in terms of constraints on possibility distributions. This allows us to uncover a new form of disjunction, called weak disjunction, that has not been previously considered in the literature. In addition to introducing and motivating the semantics of weak disjunction, we also pinpoint its computational complexity. In particular, while the complexity of most reasoning tasks coincides with standard disjunctive ASP, we find that brave reasoning for programs with weak disjunctions is easier.

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Realising memory intensive applications such as image and video processing on FPGA requires creation of complex, multi-level memory hierarchies to achieve real-time performance; however commerical High Level Synthesis tools are unable to automatically derive such structures and hence are unable to meet the demanding bandwidth and capacity constraints of these applications. Current approaches to solving this problem can only derive either single-level memory structures or very deep, highly inefficient hierarchies, leading in either case to one or more of high implementation cost and low performance. This paper presents an enhancement to an existing MC-HLS synthesis approach which solves this problem; it exploits and eliminates data duplication at multiple levels levels of the generated hierarchy, leading to a reduction in the number of levels and ultimately higher performance, lower cost implementations. When applied to synthesis of C-based Motion Estimation, Matrix Multiplication and Sobel Edge Detection applications, this enables reductions in Block RAM and Look Up Table (LUT) cost of up to 25%, whilst simultaneously increasing throughput.

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Direct experience of social work in another country is making an increasingly important contribution to internationalising the social work academic curriculum together with the cultural competency of students. However at present this opportunity is still restricted to a limited number of students. The aim of this paper is to describe and reflect on the production of an audio-visual presentation as representing the experience of three students who participated in an exchange with a social work programme in Pune, India. It describes and assesses the rationale, production and use of video to capture student learning from the Belfast/Pune exchange. We also describe the use of the video in a classroom setting with a year group of 53 students from a younger cohort. This exercise aimed to stimulate students’ curiosity about international dimensions of social work and add to their awareness of poverty, social justice, cultural competence and community social work as global issues. Written classroom feedback informs our discussion of the technical as well as the pedagogical benefits and challenges of this approach. We conclude that some benefit of audio-visual presentation in helping students connect with diverse cultural contexts, but that a complementary discussion challenging stereotyped viewpoints and unconscious professional imperialism is also crucial.

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PURPOSE: To study the effect of multimedia education on acceptance of comprehensive eye examinations (CEEs), critical for detecting glaucoma and diabetic eye disease, among rural Chinese patients using a randomized, controlled design.
METHODS: Patients aged ≥40 years were recruited from 52 routine clinic sessions (26 intervention, 26 control) conducted at seven rural hospitals in Guangdong, China. Subjects answered demographic questionnaires, were tested on knowledge about CEEs and chronic eye disease, and were told the cost of examination (range US$0-8). At intervention sessions, subjects were cluster-randomized to view a 10-minute video on the value of CEEs and retested. Control subjects were not retested. Trial outcomes were acceptance of CEEs (primary outcome) and final knowledge scores (secondary outcome).
RESULTS: At baseline, >70% (p = 0.70) of both intervention (n = 241, 61.2 ± 12.3 years) and control (n = 218, 58.4 ± 11.7 years) subjects answered no knowledge questions correctly, but mean scores on the test (maximum 5 points) increased by 1.39 (standard deviation 0.12) points (p < 0.001) after viewing the video. Intervention (73.0%) and control (72.9%) subjects did not differ in acceptance of CEEs (p > 0.50). In mixed-effect logistic regression models, acceptance of CEEs was associated with availability of free CEEs (odds ratio 18.3, 95% confidence interval 1.32-253.0), but not group assignment or knowledge score. Acceptance was 97.5% (79/81) when free exams were offered.
CONCLUSIONS: Education increased knowledge about but not acceptance of CEEs, which was generally high. Making CEEs free could further increase acceptance.

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BACKGROUND: This study aims to assess the quality of various steps of manual small incision cataract surgery and predictors of quality, using video recordings.
DESIGN: This paper applies a retrospective study.
PARTICIPANTS: Fifty-two trainees participated in a hands-on small incision cataract surgery training programme at rural Chinese hospitals.
METHODS: Trainees provided one video each recorded by a tripod-mounted digital recorder after completing a one-week theoretical course and hands-on training monitored by expert trainers. Videos were graded by two different experts, using a 4-point scale developed by the International Council of Ophthalmology for each of 12 surgical steps and six global factors. Grades ranged from 2 (worst) to 5 (best), with a score of 0 if the step was performed by trainers.
MAIN OUTCOME MEASURES: Mean score for the performance of each cataract surgical step rated by trainers.
RESULTS: Videos and data were available for 49/52 trainees (94.2%, median age 38 years, 16.3% women and 77.5% completing > 50 training cases). The majority (53.1%, 26/49) had performed ≤ 50 cataract surgeries prior to training. Kappa was 0.57∼0.98 for the steps (mean 0.85). Poorest-rated steps were draping the surgical field (mean ± standard deviation = 3.27 ± 0.78), hydro-dissection (3.88 ± 1.22) and wound closure (3.92 ± 1.03), and top-rated steps were insertion of viscoelastic (4.96 ± 0.20) and anterior chamber entry (4.69 ± 0.74). In linear regression models, higher total score was associated with younger age (P = 0.015) and having performed >50 independent manual small incision cases (P = 0.039).
CONCLUSIONS: More training should be given to preoperative draping, which is poorly performed and crucial in preventing infection. Surgical experience improves ratings.© 2015 Royal Australian and New Zealand College of Ophthalmologists.

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PURPOSE. To evaluate an educational intervention promoting acceptance of cataract surgery in rural China using a randomized controlled design. METHODS. Patients aged 50 years or older with presenting visual acuity (PVA) less than 6/18 in one or both eyes due to cataract were recruited from 26 screening sessions (13 intervention, 13 control) conducted by five rural hospitals in Guangdong, China. At intervention sessions, subjects were shown a 5- minute informational video, and counseled about cataract, surgery, and surgical cost. During screening, all subjects answered questionnaires on knowledge and attitudes about cataract, their finances, and transportation, and were referred for definitive examination if eligible. Study outcomes were acceptance of surgery (principal outcome) and hospital followup. RESULTS. Subjects in the intervention group were younger than controls (P = 0.01), but the groups did not otherwise differ. Among 212 intervention patients and 222 controls, no differences in knowledge and attitude regarding cataract were found. Surgery was accepted by 31.1% of intervention patients and 34.2% of controls (P > 0.50). Predictors of acceptance included younger age, worse logMAR PVA, knowing that cataract can be treated surgically only, greater anticipated loss in income from hospitalization, and greater house floor space per person. Membership in the intervention group was not associated with accepting surgery (odds ratio [OR]=1.11, 95% confidence interval [CI] 0.67-1.84) or hospital follow-up (OR= 1.03, 95% CI = 0.63-1.67). CONCLUSIONS. Educational interventions that successfully impart the knowledge that cataract can be only treated surgically may be more effective in increasing uptake in this setting. © 2012 The Association for Research in Vision and Ophthalmology, Inc.

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OBJECTIVE: To test an educational intervention promoting the purchase of spectacles among Chinese children. DESIGN: Randomized, controlled trial. PARTICIPANTS: Children in years 1 and 2 of all 20 junior and senior high schools (ages 12-17 years) in 3 rural townships in Guangdong, China. METHODS: Children underwent visual acuity (VA) testing, and parents of participants with presenting VA worse than 6/12 in either eye improving by more than 2 lines with cycloplegic refraction were recommended to purchase glasses. Children at 10 randomly selected schools received a lecture, video, and classroom demonstration promoting spectacle purchase. MAIN OUTCOME MEASURES: Self-reported purchase of spectacles (primary outcome) and observed wear or possession of newly purchased glasses (secondary outcome) at follow-up examinations (mean, 219 ± 87 days after the baseline visit). RESULTS: Among 15 404 eligible children, examinations were completed for 6379 (74.6%) at intervention schools and 5044 (73.6%) at control schools. Spectacles were recommended for 2236 (35.1%) children at intervention schools and for 2212 (43.9%) at control schools. Of these, 417 (25.7%) intervention schools children and 537 (34.0%, P = 0.45) control schools children reported buying glasses. Predictors of purchase in regression models included female gender (P = 0.02), worse uncorrected VA (P < 0.001), and higher absolute value of refractive error (P = 0.001). Neither the rate of self-reported purchase of glasses or observed wear or possession of newly purchased glasses differed between control schools and intervention schools in mixed-effect logistic regression models. Among children not purchasing glasses, 21.7% had better-eye VA of worse than 6/18. CONCLUSIONS: An intervention based on extensive pilot testing and focus groups in the area failed to promote spectacle purchase or wear. The high burden of remaining uncorrected poor vision underscores the need to develop better interventions. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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ABSTRACT
The proliferation in the use of video lecture capture in universities worldwide presents an opportunity to analyse video watching patterns in an attempt to quantify and qualify how students engage and learn with the videos. It also presents an opportunity to investigate if there are similar student learning patterns during the equivalent physical lecture. The goal of this action based research project was to capture and quantitatively analyse the viewing behaviours and patterns of a series of video lecture captures across several university Java programming modules. It sought to study if a quantitative analysis of viewing behaviours of Lecture Capture videos coupled with a qualitative evaluation from the students and lecturers could be correlated to provide generalised patterns that could then be used to understand the learning experience of students during videos and potentially face to face lectures and, thereby, present opportunities to reflectively enhance lecturer performance and the students’ overall learning experience. The report establishes a baseline understanding of the analytics of videos of several commonly used pedagogical teaching methods used in the delivery of programming courses. It reflects on possible concurrences within live lecture delivery with the potential to inform and improve lecturing performance.

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In this paper we give an overview of current investigations into the incorporation of cutting edge technologies within the Higher Education teaching domain. In particular, the role of audio is discussed through a number of case studies. The paper then concludes with a discussion of the authors' plans to incorporate audio and video content as supplementary course material for a technical undergraduate module

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A key issue for the social work profession concerns the nature, quality and content of communicative encounters with children and families. This article introduces some findings from a project funded by the Economic and Social Research Council (ESRC) that took place across the United Kingdom between 2013 and 2015, which explored how social workers communicate with children in their everyday practice. The Talking and Listening to Children (TLC) project had three phases: the first was ethnographic, involving observations of social workers in their workplace and during visits; the second used video-stimulated recall with a small number of children and their social workers; and the third developed online materials to support social workers. This paper discusses findings from the first phase. It highlights a diverse picture regarding the context and content of communicative processes; it is argued that attention to contextual issues is as important as focusing on individual practitioners’ behaviours and outlines a model for so doing.

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With the rapid development of internet-of-things (IoT), face scrambling has been proposed for privacy protection during IoT-targeted image/video distribution. Consequently in these IoT applications, biometric verification needs to be carried out in the scrambled domain, presenting significant challenges in face recognition. Since face models become chaotic signals after scrambling/encryption, a typical solution is to utilize traditional data-driven face recognition algorithms. While chaotic pattern recognition is still a challenging task, in this paper we propose a new ensemble approach – Many-Kernel Random Discriminant Analysis (MK-RDA) to discover discriminative patterns from chaotic signals. We also incorporate a salience-aware strategy into the proposed ensemble method to handle chaotic facial patterns in the scrambled domain, where random selections of features are made on semantic components via salience modelling. In our experiments, the proposed MK-RDA was tested rigorously on three human face datasets: the ORL face dataset, the PIE face dataset and the PUBFIG wild face dataset. The experimental results successfully demonstrate that the proposed scheme can effectively handle chaotic signals and significantly improve the recognition accuracy, making our method a promising candidate for secure biometric verification in emerging IoT applications.

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Research in the field of sports performance is constantly developing new technology to help extract meaningful data to aid in understanding in a multitude of areas such as improving technical or motor performance. Video playback has previously been extensively used for exploring anticipatory behaviour. However, when using such systems, perception is not active. This loses key information that only emerges from the dynamics of the action unfolding over time and the active perception of the observer. Virtual reality (VR) may be used to overcome such issues. This paper presents the architecture and initial implementation of a novel VR cricket simulator, utilising state of the art motion capture technology (21 Vicon cameras capturing kinematic profile of elite bowlers) and emerging VR technology (Intersense IS-900 tracking combined with Qualisys Motion capture cameras with visual display via Sony Head Mounted Display HMZ-T1), applied in a cricket scenario to examine varying components of decision and action for cricket batters. This provided an experience with a high level of presence allowing for a real-time egocentric view-point to be presented to participants. Cyclical user-testing was carried out, utilisng both qualitative and quantitative approaches, with users reporting a positive experience in use of the system.

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Among the many discussions and studies related to video games, one of the most recurrent, widely debated and important relates to the experience of playing video games. The gameplay experience – as appropriated in this study – is the result of the interplay between two essential elements: a video game and a player. Existing studies have explored the resulting experience of video game playing from the perspective of the video game or the player, but none appear to equally balance both of these elements. The study presented here contributes to the ongoing debate with a gameplay experience model. The proposed model, which looks to equally balance the video game and the player elements, considers the gameplay experience to be both an interactive experience (related to the process of playing the video game) and an emotional experience (related to the outcome of playing the video game). The mutual influence of these two experiences during video game play ultimately defines the gameplay experience. To this gameplay experience contributes several dimensions, related to both the video game and player: the video game includes a mechanics, interface and narrative dimension; the player includes a motivations, expectations and background dimension. Also, the gameplay experience is initially defined by a gameplay situation, conditioned by an ambient in which gameplay takes place and a platform on which the video game is played. In order to initially validate the proposed model and attempt to show a relationship among the multiple model dimensions, a multi-case study was carried out using two different video games and player samples. In one study, results show significant correlations between multiple model dimensions, and evidence that video game related changes influence player motivations as well as player visual behavior. In specific player related analysis, results show that while players may be different in terms of background and expectations regarding the game, their motivation to play are not necessarily different, even if their performance in the game is weak. While further validation is necessary, this model not only contributes to the gameplay experience debate, but also demonstrates in a given context how player and video game dimensions evolve during video game play.

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Abstract of paper delivered at the 17th International Reversal Theory Conference, Day 3, session 4, 01.07.15

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This paper reports on the first known empirical use of the Reversal Theory State Measure (RTSM) since its publication by Desselles et al. (2014). The RTSM was employed to track responses to three purposely-selected video commercials in a between-subjects design. Results of the study provide empirical support for the central conceptual premise of reversal theory, the experience of metamotivational reversals and the ability of the RTSM to capture them. The RTSM was also found to be psychometrically sound after adjustments were made to two of its three component subscales. Detailed account and rationale is provided for the analytical process of assessing the psychometric robustness of the RTSM, with a number of techniques and interpretations relating to component structure and reliability discussed. Agreeability and critique of the two available versions of the RTSM – the bundled and the branched – is also examined. Researchers are encouraged to assist development of the RTSM through further use, taking into account the analysis and recommendations presented.