Improving the Performance of Web-Streaming by Super-Resolution Upscaling

In order to provide the user with the best quality of experience, handling network heterogeneity is essential. In this paper, we investigate the design of a cross layer architecture for scalable video streaming applications in the context of heterogeneous broadband networks. We use the data rate adaptation feature in the video streaming application to meet the destination MAC/physical layer conditions and resource availability. Resources include the end-to-end available bandwidth between the source video server and customers from heterogeneous networks including WiMax, WiFi, 3G, and wired networks. We also introduce an enhanced admission control function at the destination gateway (to which the destination is attached) that takes into account video adaptability property. In order to illustrate the effectiveness of our mechanism, we implemented our solution named CLO (Cross Layer Optimizer) in the QualNet simulator over a WiMAX network. We utilize the existing MAC management messages exchanged between base and subscriber stations (BS and SS) and provide them to the video streaming application via a specific CLO interface. In order to assess the performance of CLO, we conducted extensive simulations using a personalized scalable video traffic generator, capable of providing different video data rates. The simulation results confirm remarkable improvement in the quality perceived by the user.

To determine the prevalence of small lung nodules on low-dose helical computed tomography (CT) in a Western Australian cohort of asymptomatic long-term cigarette smokers and to compare this with a large, similarly derived cohort of North Americans from the Mayo Clinic Lung Cancer Screening Trial. Forty-nine asymptomatic long-term cigarette smokers of minimum age 50 years underwent a low-dose 64-slice helical CT of the lungs. Images were viewed on a soft copy reporting station with thin section axial and coronal images, maximum intensity projection images, and advanced image manipulation tools. The prevalence of all nodules was 39%, significantly lower than the Mayo Clinic cohort prevalence of 51% (P < 0.01, Fisher's exact test), despite the use of more advanced imaging technology and image manipulation designed to increase the sensitivity for nodules. The prevalence of small nodules in asymptomatic long-term cigarette smokers in Western Australia is high, though significantly less than that found in a large study in North America. The authors postulate this is due to the relatively low rates of mycobacterium tuberculosis and soil-derived fungal pulmonary infections in Western Australia, as well as a lower degree of urban air pollution.

We analyze how fast we can solve general systems of multivariate equations of various low degrees over \({\mathbb{F}_{2}}\); this is a well known hard problem which is important both in itself and as part of many types of algebraic cryptanalysis. Compared to the standard exhaustive search technique, our improved approach is more efficient both asymptotically and practically. We implemented several optimized versions of our techniques on CPUs and GPUs. Our technique runs more than 10 times faster on modern graphic cards than on the most powerful CPU available. Today, we can solve 48+ quadratic equations in 48 binary variables on a 500-dollar NVIDIA GTX 295 graphics card in 21 minutes. With this level of performance, solving systems of equations supposed to ensure a security level of 64 bits turns out to be feasible in practice with a modest budget. This is a clear demonstration of the computational power of GPUs in solving many types of combinatorial and cryptanalytic problems.

A new type of three-dimensional (3-D) display recently introduced on the market holds great promise for the future of 3-D visualization, communication, and entertainment. This so-called automultiscopic display can deliver multiple views without glasses, thus allowing a limited "look-around" (correct motion-parallax). Central to this technology is the process of multiplexing several views into a single viewable image. This multiplexing is a complex process involving irregular subsampling of the original views. If not preceded by low-pass filtering, it results in aliasing that leads to texture as well as depth distortions. In order to eliminate this aliasing, we propose to model the multiplexing process with lattices, find their parameters and then design optimal anti-alias filters. To this effect, we use multidimensional sampling theory and basic optimization tools. We derive optimal anti-alias filters for a specific automultiscopic monitor using three models: the orthogonal lattice, the nonorthogonal lattice, and the union of shifted lattices. In the first case, the resulting separable low-pass filter offers significant aliasing reduction that is further improved by hexagonal-passband low-pass filter for the nonorthogonal lattice model. A more accurate model is obtained using union of shifted lattices, but due to the complex nature of repeated spectra, practical filters designed in this case offer no additional improvement. We also describe a practical method to design finite-precision, low-complexity filters that can be implemented using modern graphics cards.

We present a fully parallelized, high-performance, OpenGL-based approach to compute obstructed area-to-area (A2A) view factors for radiative heat transfer. The A2A view factors are computed from the defining surface integral by Gaussian quadrature. The values of the integrand, i.e. the point-to-area view factors, are computed using an OpenGL-based hemicube (HC) method to efficiently solve the obstruction problem by exploiting the hardware-accelerated visibility testing on modern graphics cards. The final steps to maximize hardware usage are rendering the HC and performing the numerical quadrature in parallel such that data transfer times are completely shadowed by computations. To demonstrate the power of our approach we compute the A2A view factor matrices for a warehouse equipped with ceramic infrared heaters and a test cabin conforming to EN 442 containing a section of a panel radiator. To judge the quality of the results we measure the deviation from unity of the area-weighted column sums of the view factor matrix and the error in radiant flux balance. Compared to a previous, ray-tracing-based implementation, we gain three orders of magnitude in speed in the view factor computation. Conservation of radiant flux is also substantially improved.

Security is an increasingly growing concern for network communications and video is an emerging segment of network traffic that uses large amounts of bandwidth. Streaming video, vs. downloading a video for later viewing, requires a continuous, high data rate. The data rate will vary depending on the quality of the video. Video surveillance is a streaming video application that in addition may require securing the data stream to prevent others from viewing it as well as prevent any tampering of that video stream. There are two parts to secure communication, key distribution and ciphers. A cipher requires a secret key that is used to encrypt data (plaintext), transforming it into an unreadable form (ciphertext) and then to decrypt it back into its original form. Key distribution is the method used to exchange the secret key between the desired end users and no one else. Current block ciphers are relatively slow compared to existing bandwidth because they require a substantial amount of processing that must compete for CPU cycles with the video encoding and compression processing. Frequently changing keys is thought to increase security, but the public key exchange method requires even more processing than the cipher. Cipher and key exchange processing can be off-loaded from the CPU, when the communication end point is the other end of the link, by using dedicated hardware called a link encryptor. Current classical security algorithms are based on the perceived computational complexity of certain mathematical functions and have not been proved secure. The public key algorithm is at risk from future quantum computers, whereas block ciphers are only weakened and an easy fix is to double the length of the key. Both are constantly at risk from a potential break through algorithm. Communications channels that exploit properties unique to quantum systems have been shown to enable functionality that cannot be achieved by classical means. If a high level of security is deemed necessary for the video stream, one might consider the use of a One-Time-Pad cipher [Wikipedia 2010], the only provably secure cipher, along with Quantum Key Distribution (QKD), also a provably secure method of exchanging the secret keys used by a cipher. QKD is a protocol based on the quantum laws of physics and is provably information theoretically secure to accomplish key distribution [Gisin, et al., 2002]. QKD keys, when used with a One-Time-Pad cipher, can provide secure communications. A One-Time-Pad cipher algorithm performs an Exclusive OR (XOR) on a random secret key and the message. This is a simple operation that incurs little overhead compared to the more common

Adaptive and ubiquitous video streaming over Wireless Mesh Networks

Quality of experience (QoE) over wireless networks has attracted attention from industry and academia due to an increase in video streaming applications. Several researchers have attempted to understand the factors affecting QoE and design appropriate quality control strategies. Normally, video streaming is initiated by a user who accesses video contents over wireless networks using a smart device held at various viewing distances. Each aforementioned factor has the potential to affect QoE of the viewed session. However, several studies explore the behavior of wireless networks on video streaming QoE. To understand the effects of other factors on QoE, this paper investigates the influence of the device's visual features, viewing distance, and content factors on video streaming. The study adopted an emulation technique to conduct multi-factor experiments designed using the Taguchi method. The 5-ways ANOVA analysis revealed that the effects of smart-device visual features, viewing distance, and content types are significant on video streaming QoE at p&lt;0.05. Moreover, smart devices with a pixel density index of more than 200 ppi produce high QoE, with the viewing distance limited to 45 cm. Lastly, the video bitrate greater than 1024 kbps produced a good QoE regardless of the frame rates.

Documentation is a fundamental activity of modern book conservation to record both historical evidence and the state of conservation of objects to assess (and plan) their needs for treatment, digitization, exhibitions, and other activities. Documentation generally involves the careful description of materials, techniques, and structures, recording the physical characteristics of the artefacts examined and statistical analyses of such information as well as illustrations, diagrams, and/or photographs. Historically, documentation records resided in paper archives, while today, most departments have switched to digital documents and ad hoc databases. In addition to descriptive records, photographic documentation for many years has been used as a vital source of information on the state of conservation of books and documents, and, more recently, high resolution and advanced imaging and image processing are becoming increasingly important, as their ability to enhance documentation can expand the capabilities of conservation and preservation professionals. This chapter provides an overview of book conservation documentation, balancing what can be conveyed through verbal descriptions and pictorial representations, and presents current trends and foreseen technological advancements in the field.

Replication strategy has been considered as a promising technique for improving data accessibility as well as reducing gateway overload in wireless mesh networks (WMNs). In this regard, popular data is stored in some indicated mesh routers within the network being closer to the users. However, in video streaming applications over WMNs, due to the large size of the videos, it is very challenging for replication strategies to achieve a high quality of experience (QoE) while consuming a minimum storage capacity requirement (SCR). In this paper, as a solution, we propose a novel replication strategy to overcome such challenge by determining an optimal replication density for each segment of a video streaming. The optimal result is based on exploiting not only the skewed access probabilities of video segments as conventional replication strategies but also the skewed encoding rate-distortion information and the loss probability of each frame of a segment. We carefully study the optimization problem in two forms. In the original problem form, our method consumes a minimum SCR under a given constraint of quality playback. In the duality problem form, the proposed scheme provides highest quality playback for a given SCR constraint. Simulation results show that our proposed approach gains a better performance in terms of QoE improvement and SCR saving compared to other existing replication strategies.

Vehicular ad-hoc networks (VANETs) are used for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. The IEEE 802.11p/WAVE (Wireless Access in Vehicular Environment) and with WAVE Short Messaging Protocol (WSMP) has been proposed as the standard protocol for designing applications for VANETs. This communication protocol must be thoroughly tested before reliable and efficient applications can be built using its protocols. In this paper, we perform on-road experiments in a variety of scenarios to evaluate the performance of the standard. We use commercial VANET devices with 802.11p/WAVE compliant chipsets for both BSM (basic safety messages) as well as video streaming applications using WSMP as a communication protocol. We show that while the standard performs well for BSM application in lightly loaded conditions, the performance becomes inferior when traffic and other performance metric increases. Furthermore, we also show that the standard is not suitable for video streaming due to the bursty nature of traffic and the bandwidth throttling, which is a major shortcoming for V2X applications.

We study the design tradeoffs involved in video streaming in networks with QoS guarantees. We approach this problem by using a utility function to quantify the benefit a user derives from the received video sequence. This benefit is expressed as a function of the total distortion. In addition, we also consider the cost, in network resources, of a video streaming system. The goal of the network user is then to obtain the most benefit for the smallest cost. We formulate this utility maximization problem as a joint constrained optimization problem. The difference between the utility and the network cost is maximized subject to the constraint that the decoder buffer does not underflow. We present a deterministic dynamic programming approach to find the optimal tradeoff for both the constant bit rate (CBR) and renegotiated constant bit rate (RCBR) service classes. Experimental results demonstrate the benefits and the performance of the proposed approach.

WiMAX employes high speed wireless technology and enables high bit rates real time video streaming in wireless environment. Many researchers have proposed various techniques and methods to evaluate and improve video transmission over WiMAX. However, dropped packets seem always exist. This paper implements java based video streaming application over WiMAX network and examines whole frame post-decoding concealment method to reduce dropped packet effect. The result is that packet drop impact in frame can be reduced with PSNR improvement about x dB. However, as concealment performed after decoding, there is additional delay in displaying the image which causes short flicker.

In this study, a system with reinforcement learning for push-pull mesh based video streaming applications running over p2p networks is designed. In push-pull based video streaming systems, each node in the system may receive video data from more than one parent. In the proposed system, a node which started to receive insufficient video data from any parent selects a new parent with a probabilistic method based on its previous experience. Afterwards, it learns that parent's performance with Q-learning. In this paper, design parameters of the proposed system is given and performance results obtained from simulations are compared with random parent selection method. The observed results show that the proposed system is superior than the random parent selection method in terms of average bitrate and the number of parent exchanges.

Inthis paper weperform anexperimental investigation of using videoframedifferentiation inconjunction withthe TXOP facility toenhance thetransmission ofparallel multimedia streaming sessions inIEEE802.11 e.Thedelay constraints associated withtheaudio andvideo streams that comprise amultimedia session posethegreatest challenge since real-time multimedia isparticularly sensitive todelay as thepackets require astrict bounded end-to-end delay. Video streaming applications areconsidered tobebursty. This burstiness isduetotheframerateofvideo, theintrinsic hierarchical structure oftheconstituent videoframe types, andthedifferent compression ratios forthedifferent video frametypes. TheTXOP facility isparticularly suited to efficiently dealwiththis burstiness since itcanbeusedto reserve bandwidth fortheduration ofthepacket burst associated witha packetised videoframe.Through experimental investigation, weshowthat there isasignificant performance improvement forvideostreaming applications underheavily loaded conditions bydifferentiating between theconstituent video frame types. Theresults showthat video frame differentiation reduces themeanloss rate by12%and increases themeanPSNRby13.1 dB. I. INTRODUCTION Therearemanyperformance-related issues associated with thedelivery oftime-sensitive multimedia content using current IEEE802.11 WLAN standards. Amongthemost significant arelowdelivery rates, high error rates, contention betweenstations foraccesstothemedium,back-off mechanisms, collisions, signal attenuation withdistance, signal interference, etc. Forreal-time multimedia applications packet loss andpackets dropped duetoexcessive delay are theprimary factors affecting theuser-perceived quality. Realtimemultimedia isparticularly sensitive todelay asithasa strict bounded end-to-end delay constraint. Every multimedia packet mustarrive attheclient before itsplayout timewith enough time todecode anddisplay thecontents ofthepacket. Forvideo streams thedelay incurred intransmitting theentire videoframefromthesender totheclient isofparticular importance. Thelossrates incurred duetopackets being delayed pasttheir playout timeisheavily dependent onthe delayconstraint imposed on thevideostream. Video streaming applications typically impose anupper limit onthe tolerable packet loss. Specifically, thepacket lossratio is required tobekeptbelowathreshold toachieve acceptable visual quality. Although WLAN networks allow forpacket retransmissions intheeventofanunsuccessful transmission attempt, theretransmitted packet mustarrive before its