5,167 research outputs found

    Survey of image-based representations and compression techniques

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    In this paper, we survey the techniques for image-based rendering (IBR) and for compressing image-based representations. Unlike traditional three-dimensional (3-D) computer graphics, in which 3-D geometry of the scene is known, IBR techniques render novel views directly from input images. IBR techniques can be classified into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories and their representative techniques. IBR techniques demonstrate a surprising diverse range in their extent of use of images and geometry in representing 3-D scenes. We explore the issues in trading off the use of images and geometry by revisiting plenoptic-sampling analysis and the notions of view dependency and geometric proxies. Finally, we highlight compression techniques specifically designed for image-based representations. Such compression techniques are important in making IBR techniques practical.published_or_final_versio

    On the data compression and transmission aspects of panoramic video

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    This paper proposes efficient data compression and transmission techniques for panoramic video. Panoramic videos have been used as a means for representing dynamic scenes or paths along a static environment. They allow the user to change viewpoints interactively at a point in time or space. High-resolution panoramic videos, while desirable, consume a significant amount of storage and bandwidth for transmission, and make real-time decoding very compute-intensive. A high performance MPEG-like compression algorithm, which takes into account the random access requirements and the redundancies of the panoramic video, is presented. The transmission aspects of panoramic video over cable network, LAN and Internet are also briefly discussed.published_or_final_versio

    Predictors of health-related quality of life in korean patients with myocardial infarction: a longitudinal observational study

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    © 2018 Elsevier Inc. Background: Experience of myocardial infarction (MI) negatively affects different aspects of health-related quality of life (HRQoL). Objectives: This study aimed to examine trends in HRQoL of MI patients and to identify demographic, clinical and psychosocial predictors of HRQoL at three months. Methods: A total of 150 patients in South Korea were completed the study questionnaires at baseline. After three months from discharge, 136 participants completed follow-up questionnaires, including the Korean version of the MacNew Quality of Life after Myocardial Infarction Questionnaire (MacNew). Results: HRQoL significantly improved over three months. Younger age, ST-elevation MI, and higher LVEF, lower level of depression, better understanding of the illness and higher perceived social support at baseline were associated with better HRQoL at three months. Conclusion: Providing adequate information about the illness and social support as well as reducing negative psychological experiences in early days after MI may improve HRQoL of MI patients

    Correlates of health-related quality of life in patients with myocardial infarction: A literature review

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    © 2017 Elsevier Ltd Background By the increasing emphasis on health-related quality of life (HRQoL) in patients with myocardial infarction (MI), it is necessary to explore factors that affect HRQoL in this population. Objectives This study aimed to identify correlates of HRQoL in patients with MI. Design A literature review of the factors that affect HRQoL in patients with MI (1995–2016). Data sources Three main databases—CINAHL, MEDLINE and PsychINFO—were searched to retrieve relevant peer-reviewed articles published in English. Review methods In consultation with a medical librarian, we identified relevant MeSH terms and used them for searching the literature: health-related quality of life/quality of life/HRQoL/QoL, myocardial infarction/heart attack/MI and predict*/factor. Data elements were extracted and narratively described variables synthesised into four categories. Results A total of 48 studies met the inclusion criteria and were included in the review. Correlates of HRQoL in patients with MI were identified in the following categories: demographic, behavioural, disease-related, and psychosocial factors. Specific correlates included age and gender-identity for demographic factors; physical activity and smoking for behavioural factors; severity of MI, symptoms, and comorbidities for disease-related factors; anxiety and depression for psychosocial factors. Conclusions Identifying correlates of HRQoL can help identify patients who are at risk for poor HRQoL in the recovery or rehabilitation stage of post-MI. Future intervention should focus on adjustable correlates such as behavioural and psychosocial factors to promote HRQoL among patients after experiencing MI

    Deformation and stress of a composite-metal assembly

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    Compliant structures, e.g. automobile body panel and airplane wing box are widely used. A compliant structure consists of one or more flexible parts, and these parts share the mating features among them. Because of process-induced deformation and part-to-part variations, external forces are applied during the assembly process and the parts are deformed. As a result, the final assembly is pre-stressed and its geometrical shape may deviate from the designed shape. Therefore, the assembly variation and residual stress need to be analysed in order to evaluate the structure performance. In this study, a new approach based on response surface methodology is developed. A number of organised virtual experiments are conducted with the aid of finite element analysis and regression models are fitted to the resulting data. These regression models relate part variations to assembly variation and residual stress. Monte Carlo simulation can be conveniently done using these simple regression models. The effectiveness of this method was illustrated using a composite–metal assembly. It is shown that the method presented in this paper provides a practical and reliable solution to the analysis of compliant structures

    Influence of Social and Behavioural Characteristics of Users on Their Evaluation of Subjective Loudness and Acoustic Comfort in Shopping Malls

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    A large-scale subjective survey was conducted in six shopping malls in Harbin City, China, to determine the influence of social and behavioural characteristics of users on their evaluation of subjective loudness and acoustic comfort. The analysis of social characteristics shows that evaluation of subjective loudness is influenced by income and occupation, with correlation coefficients or contingency coefficients of 0.10 to 0.40 (p<0.05 or p<0.01). Meanwhile, evaluation of acoustic comfort evaluation is influenced by income, education level, and occupation, with correlation coefficients or contingency coefficients of 0.10 to 0.60 (p<0.05 or p<0.01). The effect of gender and age on evaluation of subjective loudness and acoustic comfort is statistically insignificant. The effects of occupation are mainly caused by the differences in income and education level, in which the effects of income are greater than that of education level. In terms of behavioural characteristics, evaluation of subjective loudness is influenced by the reason for visit, frequency of visit, and length of stay, with correlation coefficients or contingency coefficients of 0.10 to 0.40 (p<0.05 or p<0.01). Evaluation of acoustic comfort is influenced by the reason for visit to the site, the frequency of visit, length of stay, and also season of visit, with correlation coefficients of 0.10 to 0.30 (p<0.05 or p<0.01). In particular, users who are waiting for someone show lower evaluation of acoustic comfort, whereas users who go to shopping malls more than once a month show higher evaluation of acoustic comfort. On the contrary, the influence of the period of visit and the accompanying persons are found insignificant

    Effect of storage media and time on fin explants culture in the goldfish, Carassius auratus

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    The effect of storage media and time was investigated on fin explants culture in the goldfish (Carassius auratus). Fin explants under sterile conditions were able to produce cells at different storage media and time. On the outgrowth of cells, fin explants stored for seven days before culturing showed significantly higher growth (P&lt;0.05) as observed on the fin explants stored in Dulbecco’s modified Eagles medium (DMEM, 84.44%), phosphate buffered saline (PBS, 62.42%) and in control/fresh fin explants (100%), compared with the explants with no storage medium (25.56%) at day three of culture. From day seven to 14, all caudal fin explants exhibited a 100% outgrowth of cells regardless of treatment. However, caudal fin explants kept for 10 days in 4°C showed a significant difference (P&lt;0.05) from fin explants stored in DMEM (96.67%), PBS (75.57%) and the control (100%), as compared with no storage medium (no growth) on day three. Moreover, only 6.67% of no storage medium group could maintain outgrowth of cells, while other treatment group reached 100% of outgrowth after 14 days of culture.Key words: Carassius auratus, fin explants, goldfish, storage

    Intelligent medical case based e-learning system

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    Educational theory has purported the notion that student-centric modes of learning are more effective in enhancing student engagement and by extension, learning outcomes. However, the translation of this theoretical pedagogy of learning into an applied model for medical training has been fraught with difficulty due to the structural complexity of creating a classroom environment that enables students to exercise full autonomy. In this paper, we propose an intelligent computational e-learning platform for case-based learning (CBL) in Medicine that enriches and enhances the learning experiences of medical students by exposing them to simulated real-world clinical contexts. We argue that computational systems in Medicine should not merely provide a passive outlay of information, but instead promote active engagement through an immersive learning experience. This is achieved through a digital platform that renders a virtual patient simulation, which allows students to assess, diagnose, treat and test patients as they would in the real-world
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