46 research outputs found
BOLA360: Near-optimal View and Bitrate Adaptation for 360-degree Video Streaming
Recent advances in omnidirectional cameras and AR/VR headsets have spurred
the adoption of 360-degree videos that are widely believed to be the future of
online video streaming. 360-degree videos allow users to wear a head-mounted
display (HMD) and experience the video as if they are physically present in the
scene. Streaming high-quality 360-degree videos at scale is an unsolved problem
that is more challenging than traditional (2D) video delivery. The data rate
required to stream 360-degree videos is an order of magnitude more than
traditional videos. Further, the penalty for rebuffering events where the video
freezes or displays a blank screen is more severe as it may cause
cybersickness. We propose an online adaptive bitrate (ABR) algorithm for
360-degree videos called BOLA360 that runs inside the client's video player and
orchestrates the download of video segments from the server so as to maximize
the quality-of-experience (QoE) of the user. BOLA360 conserves bandwidth by
downloading only those video segments that are likely to fall within the
field-of-view (FOV) of the user. In addition, BOLA360 continually adapts the
bitrate of the downloaded video segments so as to enable a smooth playback
without rebuffering. We prove that BOLA360 is near-optimal with respect to an
optimal offline algorithm that maximizes QoE. Further, we evaluate BOLA360 on a
wide range of network and user head movement profiles and show that it provides
to more QoE than state-of-the-art algorithms. While ABR
algorithms for traditional (2D) videos have been well-studied over the last
decade, our work is the first ABR algorithm for 360-degree videos with both
theoretical and empirical guarantees on its performance.Comment: 25 page
A FRAMEWORK FOR ORGANIZATIONAL ARCHITECTURE OF ELECTRONIC CITY AND ELECTRONIC MUNICIPALITY
This study provides a framework for enterprise architecture in electronic city is electronic municipality. Nowadays, information technology as an emerging phenomenon has a special place in the world. Development of information and communication technology causes many changes in various fields, including emerging e-cities, municipalities and citizens. However, e-city and e-municipality need essential enterprise architecture. In order to develop enterprise architecture of e-city and e-municipality, enterprise architecture maturity method should be applied. Therefore, one of the most important needs of organizations is to choose important activities according to limitations. The studies show that there is a close relationship between IT, enterprise architecture, e- city and e-municipality. This study aimed to clarify the concept of IT, enterprise architecture, electronic city and e- municipality and how they are related to each other. Is the existence of each of IT, enterprise architecture, electronic and electronic municipal requires each other
THE ROLE OF GREEN ROOFS IN URBAN SUSTAINABILITY
Dynamic urban processes and constant evolutions in the types of living as well as technological advances have changed and manipulated living environments for human beings. The increasing growth in the population of urban regions and the escalation of socioeconomic problems have forced human beings to live in matchbox apartments during the last a few decades. Modern human beings have to encounter different daily activities to make living; hence, having a shelter which can bring peace and relief has become a dream for him. Recent urban views and sights have been changed into apartments and tall towers in the residential areas which have made human habitats gloomy and bleak and have created several problems for modern citizens. It can be argued that, regardless of the internal peace of houses, urban citizens need beautiful and green natural views and sceneries far from the tensions of work environments so as to comfort their minds and imaginations. Projects for modernizing, optimizing and creating new urban spaces are realized in different areas for many years. The present study is intended to examine the concept and idea of green garden which has been proposed by developed countries. The concept of green garden was proposes as an attempt to fulfill tranquility, peace and a desirable habitat. The present study investigated and evaluated this proposition based on the following criteria: compatibility, desirability, efficiency, comfort, safety and health
REVIEW AND ANALYSIS THE INDICATORS OF GREEN CITY WITH NDVI (STUDY CASE SHEIKH TAPPEH NEIGHBORHOOD IN URMIA)
Increasing urbanization and rapid population expansion and its specific problems such as air and water pollution, environmental degradation, increase in mental illness, housing, infrastructure, education and transportation and other problems of urban society more than ever threatens this contrary which is against the principles of sustainable development and green city projects is one of the urban environment measures in this field that has achieved success in the world. The idea is that the city is a place that forms human opportunities and abilities and in addition each city has its own life, soul and even its own special character therefore each city most be recognized as a whole and form it as a place of residence. Specific problems of urbanization has faced urban management with challenges in the field of population density, housing shortages, environmental degradation, pollution and supplying infrastructure services and facilities, and issues of the Green City project is more involved which results less public participating in cities sustainable development. This study analyzes the characteristics of green city’s indexes in Sheikh Tappeh neighborhood in Urmia. This is a descriptive -analysis study and data collection was conducted by library documents and field survey. According to survey results Sheikh Tappeh neighborhood is far from favorable indicators of health status and standards of green city and city planning and public participation is required
Segmentation of Cells from 3-D Confocal Images of Live Embryo
Abstract: Partial-differential-equation-based segmentation has been employed to accurately extract the shapes of membranes and nuclei from time lapse confocal microscopy images, taken throughout early Zebrafish embryogenesis. This strategy is a prerequisite for an accurate quantitative analysis of cell shape and morphodynamics during organogenesis and is the basis for an integrated understanding of biological processes. This data will also serve for the measurement of the variability between individuals in a population. The segmentation of cellular structures is achieved by first using an edge-preserving image filtering method for noise reduction and then applying an algorithm for cell shape reconstruction based on the Subjective Surfaces technique
REVIEW AND ANALYSIS THE INDICATORS OF GREEN CITY WITH NDVI (STUDY CASE SHEIKH TAPPEH NEIGHBORHOOD IN URMIA)
Increasing urbanization and rapid population expansion and its specific problems such as air and water pollution, environmental degradation, increase in mental illness, housing, infrastructure, education and transportation and other problems of urban society more than ever threatens this contrary which is against the principles of sustainable development and green city projects is one of the urban environment measures in this field that has achieved success in the world. The idea is that the city is a place that forms human opportunities and abilities and in addition each city has its own life, soul and even its own special character therefore each city most be recognized as a whole and form it as a place of residence. Specific problems of urbanization has faced urban management with challenges in the field of population density, housing shortages, environmental degradation, pollution and supplying infrastructure services and facilities, and issues of the Green City project is more involved which results less public participating in cities sustainable development. This study analyzes the characteristics of green city’s indexes in Sheikh Tappeh neighborhood in Urmia. This is a descriptive -analysis study and data collection was conducted by library documents and field survey. According to survey results Sheikh Tappeh neighborhood is far from favorable indicators of health status and standards of green city and city planning and public participation is required
Competitive Algorithms for the Online Multiple Knapsack Problem with Application to Electric Vehicle Charging
We introduce and study a general version of the fractional online knapsack problem with multiple knapsacks, heterogeneous constraints on which items can be assigned to which knapsack, and rate-limiting constraints on the assignment of items to knapsacks. This problem generalizes variations of the knapsack problem and of the one-way trading problem that have previously been treated separately, and additionally finds application to the real-time control of electric vehicle (EV) charging. We introduce a new algorithm that achieves a competitive ratio within an additive factor of one of the best achievable competitive ratios for the general problem and matches or improves upon the best-known competitive ratio for special cases in the knapsack and one-way trading literatures. Moreover, our analysis provides a novel approach to online algorithm design based on an instance-dependent primal-dual analysis that connects the identification of worst-case instances to the design of algorithms. Finally, we illustrate the proposed algorithm via trace-based experiments of EV charging
Competitive Algorithms for the Online Multiple Knapsack Problem with Application to Electric Vehicle Charging
We introduce and study a general version of the fractional online knapsack problem with multiple knapsacks, heterogeneous constraints on which items can be assigned to which knapsack, and rate-limiting constraints on the assignment of items to knapsacks. This problem generalizes variations of the knapsack problem and of the one-way trading problem that have previously been treated separately, and additionally finds application to the real-time control of electric vehicle (EV) charging. We introduce a new algorithm that achieves a competitive ratio within an additive factor of one of the best achievable competitive ratios for the general problem and matches or improves upon the best-known competitive ratio for special cases in the knapsack and one-way trading literatures. Moreover, our analysis provides a novel approach to online algorithm design based on an instance-dependent primal-dual analysis that connects the identification of worst-case instances to the design of algorithms. Finally, we illustrate the proposed algorithm via trace-based experiments of EV charging
Markers of Prominence in Persian General Practitioners’ Books and Online Medical Journals
Giving certain elements more significance than others in the same context is called prominence. This study aims at identifying and comparing markers of focal and thematic prominence in Persian general practitioners’ books (GPBs) and Persian online medical journals (OMJs) based on Levinsohn’s model. The data were gathered from 100 texts from two written Persian GPBs and 100 texts from two Persian OMJs. SPSS software version 24 was used to evaluate the data. Results demonstrated “emphatic markers” such as fæqæt ‘just’ were used for focal prominence much more frequently in OMJs than in GPBs. In addition, significant differences were observed between GPBs and OMJs with regard to the markers of focal prominence and prominence in general, but not with regard to markers of thematic prominence. This may be related to the twofold effect of the different discourse types and different addressees of these texts