Real-time interactive video streaming over lossy networks: high performance low delay error resilient algorithms

According to Cisco's latest forecast, two-thirds of the world's mobile data traffic and 62 percent of the consumer Internet traffic will be video data by the end of 2016. However, the wireless networks and Internet are unreliable, where the video traffic may undergo packet loss and delay. Thus robust video streaming over unreliable networks, i.e., Internet, wireless networks, is of great importance in facing this challenge. Specifically, for the real-time interactive video streaming applications, such as video conference and video telephony, the allowed end-to-end delay is limited, which makes the robust video streaming an even more difficult task. In this thesis, we are going to investigate robust video streaming for real-time interactive applications, where the tolerated end-to-end delay is limited. Intra macroblock refreshment is an effective tool to stop error propagations in the prediction loop of video decoder, whereas redundant coding is a commonly used method to prevent error from happening for video transmission over lossy networks. In this thesis two schemes that jointly use intra macroblock refreshment and redundant coding are proposed. In these schemes, in addition to intra coding, we proposed to add two redundant coding methods to enhance the transmission robustness of the coded bitstreams. The selection of error resilient coding tools, i.e., intra coding and/or redundant coding, and the parameters for redundant coding are determined using the end-to-end rate-distortion optimization. Another category of methods to provide error resilient capacity is using forward error correction (FEC) codes. FEC is widely studied to protect streamed video over unreliable networks, with Reed-Solomon (RS) erasure codes as its commonly used implementation method. As a block-based error correcting code, on the one hand, enlarging the block size can enhance the performance of the RS codes; on the other hand, large block size leads to long delay which is not tolerable for real-time video applications. In this thesis two sub-GOP (Group of Pictures, formed by I-frame and all the following P/B-frames) based FEC schemes are proposed to improve the performance of Reed-Solomon codes for real-time interactive video applications. The first one, named DSGF (Dynamic sub-GOP FEC Coding), is designed for the ideal case, where no transmission network delay is taken into consideration. The second one, named RVS-LE (Real-time Video Streaming scheme exploiting the Late- and Early-arrival packets), is more practical, where the video transmission network delay is considered, and the late- and early-arrival packets are fully exploited. Of the two approaches, the sub-GOP, which contains more than one video frame, is dynamically tuned and used as the RS coding block to get the optimal performance. For the proposed DSGF approach, although the overall error resilient performance is higher than the conventional FEC schemes, that protect the streamed video frame by frame, its video quality fluctuates within the Sub-GOP. To mitigate this problem, in this thesis, another real-time video streaming scheme using randomized expanding Reed-Solomon code is proposed. In this scheme, the Reed-Solomon coding block includes not only the video packets of the current frame, but also all the video packets of previous frames in the current group of pictures (GOP). At the decoding side, the parity-check equations of the current frameare jointly solved with all the parity-check equations of the previous frames. Since video packets of the following frames are not encompassed in the RS coding block, no delay will be caused for waiting for the video or parity packets of the following frames both at encoding and decoding sides. The main contribution of this thesis is investigating the trade-off between the video transmission delay caused by FEC encoding/decoding dependency, the FEC error-resilient performance, and the computational complexity. By leveraging the methods proposed in this thesis, proper error-resilient tools and system parameters could be selected based on the video sequence characteristics, the application requirements, and the available channel bandwidth and computational resources. For example, for the applications that can tolerate relatively long delay, sub-GOP based approach is a suitable solution. For the applications where the end-to-end delay is stringent and the computational resource is sufficient (e.g. CPU is fast), it could be a wise choice to use the randomized expanding Reed-Solomon code

Cost effective technology applied to domotics and smart home energy management systems

Premio extraordinario de Trabajo Fin de Máster curso 2019/2020. Máster en Energías Renovables DistribuidasIn this document is presented the state of art for domotics cost effective technologies available on market nowadays, and how to apply them in Smart Home Energy Management Systems (SHEMS) allowing peaks shaving, renewable management and home appliance controls, always in cost effective context in order to be massively applied. Additionally, beyond of SHEMS context, it will be also analysed how to apply this technology in order to increase homes energy efficiency and monitoring of home appliances. Energy management is one of the milestones for distributed renewable energy spread; since renewable energy sources are not time-schedulable, are required control systems capable of the management for exchanging energy between conventional sources (power grid), renewable sources and energy storage sources. With the proposed approach, there is a first block dedicated to show an overview of Smart Home Energy Management Systems (SMHEMS) classical architecture and functional modules of SHEMS; next step is to analyse principles which has allowed some devices to become a cost-effective technology. Once the technology has been analysed, it will be reviewed some specific resources (hardware and software) available on marked for allowing low cost SHEMS. Knowing the “tools” available; it will be shown how to adapt classical SHEMS to cost effective technology. Such way, this document will show some specific applications of SHEMS. Firstly, in a general point of view, comparing the proposed low-cost technology with one of the main existing commercial proposals; and secondly, developing the solution for a specific real case.En este documento se aborda el estado actual de la domótica de bajo coste disponible en el mercado actualmente y cómo aplicarlo en los sistemas inteligentes de gestión energética en la vivienda (SHEMS) permitiendo el recorte de las puntas de demanda, gestión de energías renovables y control de electrodomésticos, siempre en el contexto del bajo coste, con el objetivo de lograr la máxima difusión de los SHEMS. Adicionalmente, más allá del contexto de la tecnología SHEMS, se analizará cómo aplicar esta tecnología para aumentar la eficiencia energética de los hogares y para la supervisión de los electrodomésticos. La gestión energética es uno de los factores principales para lograr la difusión de las energías renovables distribuidas; debido a que las fuentes de energía renovable no pueden ser planificadas, se requieren sistemas de control capaces de gestionar el intercambio de energía entre las fuentes convencionales (red eléctrica de distribución), energías renovables y dispositivos de almacenamiento energético. Bajo esta perspectiva, este documento presenta un primer bloque en el que se exponen las bases de la arquitectura y módulos funcionales de los sistemas inteligentes de gestión energética en la vivienda (SHEMS); el siguiente paso será analizar los principios que han permitido a ciertos dispositivos convertirse en dispositivos de bajo coste. Una vez analizada la tecnología, nos centraremos en los recursos (hardware y software) existentes que permitirán la realización de un SHEMS a bajo coste. Conocidas las “herramientas” a nuestra disposición, se mostrará como adaptar un esquema SHEMS clásico a la tecnología de bajo coste. Primeramente, comparando de modo genérico la tecnología de bajo coste con una de las principales propuestas comerciales de SHEMS, para seguidamente desarrollar la solución de bajo coste a un caso específico real

Adaptive delivery of real-time streaming video

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 87-92).While there is an increasing demand for streaming video applications on the Internet, various network characteristics make the deployment of these applications more challenging than traditional Internet applications like email and the Web. The applications that transmit data over the Internet must cope with the time-varying bandwidth and delay characteristics of the Internet and must be resilient to packet loss. This thesis examines these challenges and presents a system design and implementation that ameliorates some of the important problems with video streaming over the Internet. Video sequences are typically compressed in a format such as MPEG-4 to achieve bandwidth efficiency. Video compression exploits redundancy between frames to achieve higher compression. However, packet loss can be detrimental to compressed video with interdependent frames because errors potentially propagate across many frames. While the need for low latency prevents the retransmission of all lost data, we leverage the characteristics of MPEG-4 to selectively retransmit only the most important data in order to limit the propagation of errors. We quantify the effects of packet loss on the quality of MPEG-4 video, develop an analytical model to explain these effects, and present an RTP-compatible protocol-which we call SR-RTP--to adaptively deliver higher quality video in the face of packet loss. The Internet's variable bandwidth and delay make it difficult to achieve high utilization, Tcp friendliness, and a high-quality constant playout rate; a video streaming system should adapt to these changing conditions and tailor the quality of the transmitted bitstream to available bandwidth. Traditional congestion avoidance schemes such as TCP's additive-increase/multiplicative/decrease (AIMD) cause large oscillations in transmission rates that degrade the perceptual quality of the video stream. To combat bandwidth variation, we design a scheme for performing quality adaptation of layered video for a general family of congestion control algorithms called binomial congestion control and show that a combination of smooth congestion control and clever receiver-buffered quality adaptation can reduce oscillations, increase interactivity, and deliver higher quality video for a given amount of buffering. We have integrated this selective reliability and quality adaptation into a publicly available software library. Using this system as a testbed, we show that the use of selective reliability can greatly increase the quality of received video, and that the use of binomial congestion control and receiver quality adaptation allow for increased user interactivity and better video quality.by Nicholas G. Feamster.M.Eng

Molecular phylogeny of horseshoe crab using mitochondrial Cox1 gene as a benchmark sequence

An effort to assess the utility of 650 bp Cytochrome C oxidase subunit I (DNA barcode) gene in delineating the members horseshoe crabs (Family: xiphosura) with closely related sister taxa was made. A total of 33 sequences were extracted from National Center for Biotechnological Information (NCBI) which include horseshoe crabs, beetles, common crabs and scorpion sequences. Constructed phylogram showed beetles are closely related with horseshoe crabs than common crabs. Scorpion spp were distantly related to xiphosurans. Phylogram and observed genetic distance (GD) date were also revealed that Limulus polyphemus was closely related with Tachypleus tridentatus than with T.gigas. Carcinoscorpius rotundicauda was distantly related with L.polyphemus. The observed mean Genetic Distance (GD) value was higher in 3rd codon position in all the selected group of organisms. Among the horseshoe crabs high GC content was observed in L.polyphemus (38.32%) and lowest was observed in T.tridentatus (32.35%). We conclude that COI sequencing (barcoding) could be used in identifying and delineating evolutionary relatedness with closely related specie

Crab and cockle shells as heterogeneous catalysts in the production of biodiesel

In the present study, the waste crab and cockle shells were utilized as source of calcium oxide to transesterify palm olein into methyl esters (biodiesel). Characterization results revealed that the main component of the shells are calcium carbonate which transformed into calcium oxide upon activated above 700 °C for 2 h. Parametric studies have been investigated and optimal conditions were found to be catalyst amount, 5 wt.% and methanol/oil mass ratio, 0.5:1. The waste catalysts perform equally well as laboratory CaO, thus creating another low-cost catalyst source for producing biodiesel. Reusability results confirmed that the prepared catalyst is able to be reemployed up to five times. Statistical analysis has been performed using a Central Composite Design to evaluate the contribution and performance of the parameters on biodiesel purity

Integrated mission management operations

Operations required to launch a modular space station and to provides sustaining ground operations for support of that orbiting station throughout its 10 year mission are studied. A baseline, incrementally manned program and attendent experiment program options are derived. In addition, features of the program that significantly effect initial development and early operating costs are identified, and their impact on the program is assessed. A preliminary design of the approved modular space station configuration is formulated

Energy: A continuing bibliography with indexes, issue 17

This bibliography lists 1292 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1978 through March 31, 1978