Ligne-claire video encoding for power constrained mobile environments

In this paper we describe our experiments on digital video applications, concentrating on the static and dynamic tradeoffs involved in video playback. Our results were extracted from a controlled series of 272 tests, which we ran in three stages.In the first stage of 120 tests, we used a simple player-monitor tool to evaluate the effects of various static parameters: compression type, frame size, digitized rate, spatial quality and keyframe distribution. The tests were carried out on two Apple Macintosh platforms: at the lower end a Quadra 950, and at the higher end, a Power PC 7100/80. Our quantitative metrics included average playback rate, as well as the rate's variance over one-second intervals.The first set of experiments unveiled several anomalous latencies. To track them down we ran an additional 120 tests, from which we concluded that the video and IO operations were insufficiently tuned to each other.In the next step we attempted to correct this problem, by implementing our own video playback software and accompanying device-level handlers. Our emphasis was on achieving a controlled, deterministic coordination between the various system components. An additional set of 32 experiments were carried out on our platforms, which showed frame-rate increases of up to 325%, with associated reductions in rate variance.

Mobile technologies enable individuals to organize and manage their daily li ves through the mobile applications that are use d during the day. A ugmented reality is one of those applications that can be used on mobile devices. Expectations for the use of new technologies in educational environments increase in parallel with the technolog ical advancements. Thanks to advances in computer, internet and mobile technologies, numerous new applications have emerged that facilitate communication and interaction in educational environments. In particular, t he applications of the augmented reality technologies emerging with the advancing technology in the field of education are becoming widespread and easy -to-use. Augmented reality is a technology that enriches the learning process, created by real-time integration of the virtual elements and the real world elements. In geography teaching, different knowledge and skills are expected to be acquired by the learner , therefore augmented reality application s appeal ing to the different senses of learners can be utilized. AR technology can be used in various fields , especially in education. In addition to increasing productivity, mobile augmented reality applications would be used for multiple purposes in the field of education with the interactive facilities they offer to user such as 2D and 3D visual support and video playback.

Heterogenous cellular networks (HCN) introduce small cells within the transmission range of a macrocell. For the efficient operation of HCNs it is essential that the high-power macrocell shuts off its transmissions for an appropriate amount of time in order for the low-power small cells to transmit. This is a mechanism that allows time-domain resource partitioning (TDRP) and is critical to be optimized for maximizing the throughput of the complete HCN. In this paper, we investigate video communication in HCNs when TDRP is employed. After defining a detailed system model for video streaming in such an HCN, we consider the problem of maximizing the experienced video quality at all the users, by jointly optimizing the TDRP for the HCN, the rate allocated to each specific user, and the selected video quality transmitted to a user. The NP-hard problem is solved with a primal-dual approximation algorithm that decomposes the problem into simpler subproblems, making them amenable to fast well-known solution algorithms. Consequently , the calculated solution can be enforced in the time scale of real-life video streaming sessions. This last observation motivates the enhancement of the proposed framework to support video delivery with dynamic adaptive streaming over HTTP (DASH). Our extensive simulation results demonstrate clearly the need for our holistic approach for improving the video quality and playback performance of the video streaming users in HCNs.

Introduction: The introduction of Clinical Information Systems (CIS) to manage and store patient information has deeply modified the workflow of caregivers. As the information is no longer stored on a physical medium, caregivers depend on the presence of a computer to access patient data. This constraint has built up an invisible barrier between the source of information and the place of its use. The popularisation of mobile devices offers an oportunity to break this barrier by providing a ubiquitous access to information. The use of a mobile platform merges the advantages of a modern CIS and the mobility offered by paper. We have developed an application on a mobile device that nurses can carry along on all their visits. It allows the information gathered during their visits to be entered directly into the system. Method: The tool we present aims to manage the daily interventions of nurses. The interventions concern all kinds of treatments provided by nurses to patients. In the current organisation, nurses start their day by printing out all the daily interventions and use it as a procedure to follow. Every time a nurse performs an intervention, she takes a note indicating that the task has been done properly. When they have some spare time, nurses enter all the gathered information in the CIS. Once nurses are equipped with mobile devices, paper becomes useless. Consequently, the process is simplified. Replacing the paper by a mobile device application is not straightforward. In order to access patient information, the tool must be linked to the existing CIS of the hospital without creating too strong dependencies. Moreover, the mobile interface must be adapted to the specificities of the mobile device such as a smaller display size, a reduced computational power, a tactile-based interaction and a real-time usage. Results: In order to link the mobile application to the existing CIS, we relied on a Service Oriented Architecture (SOA). It was mandatory to think of a software architecture that would not create a dependency with any legacy system. Thus, we defined a gateway server providing centralised access for the mobile application to any required information to or from the CIS. Integrating any mobile application would only require integrating this bridge. The gateway server also clearly separates the services that are available remotely from the ones proposed as usual Web services. The developed application not only allows the validation of the interventions and the input of measures, but it also offers a simple way to define the context in which nurses are working. This context is necessary to identify the specific list of interventions for the patients under the caregiver’s responsibility. The current CIS of the HUG includes a module that provides information concerning the interventions. Its interface is adjusted for a personal computer screen. Since caregivers are accustomed to this organisation of the information, we aimed to develop an interface on a mobile device that guarantees a certain level of homogeneity with the existing PC application. However, a mobile device’s screen is of limited size, therefore the interface has been completely rebuilt to be adapted to the new display. To deal with the limited display size, we rely on hierarchy and indexicality principles. For instance, based on the hypothesis that all tasks belonging to one category and planned at the same time can be regrouped under a single item; we regroup the interventions of similar top level in a common item. Moreover, to minimise user manipulations, relevant items are automatically moved to the top. Conclusion: The current daily workflow of nurses cannot be managed consistently using a unique tool. The need to switch from paper to computer induces work overload and is a source of errors. Therefore, we have developed a program running on a mobile device that nurses can carry during their visits. This program allows to manage nurses' daily interventions in real-time. The development of such a tool has required a complete reconstruction of the classical personal computer interface. This new interface takes into account a smaller display size, an innovative interaction paradigm, and real-time constraints.

Recent years have witnessed a significant rise in the number, duration and variety of video contents, which contribute to the bulk of internet traffic. With increase in smartphone and tablet users, watching videos on mobile devices has become one of its most popular use cases. These devices live on limited battery energy which is still a major bottleneck and a source of user dissatisfaction during video playback. In this paper we introduce an intermediate framework called VIDalizer for power efficient video delivery to smartphones and tablets. This almost transparent to the user, battery aware framework takes away some of the video processing overhead from the device and intelligently tunes its parameters customized for the mobile device while delivering the video using a novel transport protocol. Our preliminary results show that this framework can significantly reduce energy consumption up to 45%–55% of a mobile device without compromising user experience.

Recently, screen recording technology is widely used by lots of applications, such as remote control, distance learning, and distance conference etc. A problem, called Asymmetric Screen Resolution (ASR) in this paper, will occur in these applications. The ASR problem means that the resolution of a recording computer is different from that of a display computer. Different computer system will have different screen resolution and the ASR problem will result in screen recording resolution mismatch between the recording computer and display computer. This paper proposes a novel CRA algorithm to apply advantage of the CUDA parallel computing for adjusting the resolution on the Graphics Processing Unit (GPU). This algorithm effectively reduces CPU utilization and guarantees the display quality after adjusting resolution. Four different application scenarios, web browsing, text editing, slide presentation, and video playback are used to test the performance of our proposed CRA algorithm. These experiments measure CPU utilization and the PSNR of image adjusted by the CRA algorithm. The experimental results show that CRA algorithm effectively reduce CPU utilization 32%~40% while using whole screen in resolution adjustment. The CRA algorithm effectively reduces CPU utilization 0.1%~13% while using difference rectangle in resolution adjustment. On image quality measurements, the PSNR value is controlled between 25db~28db while using the CRA algorithm to adjust screen resolution from 1920×1080 to 1536×864. The PSNR value is controlled between 26db~34db by using the CRA algorithm to adjust screen resolution from 1920×1080 to 960×540. Using CRA algorithm presented in this paper will definitely get a good image quality, and effectively reduce CPU utilization.

The development frameworks and the power efficiency in mobile devices have been studied separately. This paper deals with both topics together to determine how the selection of a development framework can impact on energy consumption of a mobile application. The focus is on applications with high processing load, audio and video playback. The results were analyzed and conclusions were reached.

Mobile systems and mobile applications have gained a lot of attention both in research and industry over the last years. The market share of mobile devices is constantly growing. More and more, users expect their mobile devices to provide functionality similar to the one they know from their desktop computers, but also to provide additional, mobile device specific functionality, like location based services. However, software development for mobile devices is still cumbersome and a methodology geared towards supporting the development of such mobile applications is still lacking. While there is broad agreement that developing for mobile devices is more difficult than traditional software engineering, we lack a precise understanding that goes beyond anecdotic evidence of why this is the case and how the situation can be ameliorated. We do not precisely know where and how the development of mobile application differs from “normal” software development and where new methodologies are needed. Aspects that need to be addressed in this context are, among others, the questions of software architectures for mobile applications, approaches to the software design for mobile applications and how the consequences of being mobile, e. g., changing location, changing context, changing connectivity, heterogeneous software and platforms influence the software development process and what design approaches do reflect the specialties of mobile applications and systems appropriately. While this special issue cannot provide a definite or complete answer to these questions, it does provide answers to some important aspects. In the following, we will first try to get a more thorough understanding of some of the main differences between mobile and classical application development and will then discuss how the papers contained in this special issue address these differences.

In the nowadays enterprise computerized context, there is a trend that shifts the business applications to the new mobile environments. In the light of this information, it is highly important to be knowledgeable about the software development methodologies available in order to make the right choice when it comes to developing a mobile application. The current research aims to presenting the methodological approaches regarding the development cycle of classic enterprise software versus mobile apps. In the first part of the paper a brief literature review regarding the mobile is made, for the purpose of justifying the current research theme. The most consistent part of the article puts face-to-face the classical and the new development methodologies adapted to the requirements of the new mobile environment trends. The paper also presents the challenges and limitations of mobile applications as well as few of the future trends in the researched domain.Keywords: Application 's Lifecycle Models, Agile Models, Mobile Environment, Mobile Apps1 Introduction to Mobile ApplicationsMobile applications, also referred to as mobile apps, are software applications that are usually designed to be ran on smart phones and tablet computers [1], The term apps had become extremely popular and, as a consequence, in 2010 was listed as Word of the Year by the American Dialect Society. Mobile applications are available through application distribution platforms, which are managed by mobile operating system developer.There are several major trends that we believe it contributes to the boost of using the today mobile applications:* the increased availability and options to Internet connection for mobile devices;* the shift to the new mobile environments for the business applications;* cloud application's development;* the newest research findings that identifies new technologies which increased the performance of mobile device while the price remained at the same level, allowed mobile devices to became available for a wider variety of users.Another important aspect, when it comes to mobile application development, is the number of users. Thus, the number of mobile worldwide workers in 2013 is over 1 billion and accounts for about 35% of the worldwide workforce. The structure of the above ratio shows that Asia/Pacific (including Japan) have the largest total number of mobile workers, 785 million, while the second place is taken by Western Europe whose mobile workforce reached 129.5 million in 2013 and accounts for about half of the Western European workforce population. The study [2] also highlights that US has the highest percentage of mobile workers in its workforce, with 75.5% by the end 2013 accounting to 119.7 million mobile workers. A quick glimpse to the future is displayed in the two most recent studies which predict that mobile worker population will reach 1.2 billion by 2014 (a VDC study [3]) and 1.3 billion by 2015 (an IDC study [4]).Every day, hundred thousands of mobile devices are sold and about the same number of applications is downloaded. By 2015, International Data Corporation (IDC) predicts [5] that 182.7 billion mobile will be downloaded. That's a 1600 % increase from the 10.7 billion downloaded in 2010. This information highlights the mobile user's appetite for a wide range of software applications.Cloud application development brings innovation [6] to mobile computing as mobile devices use clouds for a wide range of purposes, from data processing and data storage to other intensive data and information transactions. So far, there are few mobile cloud applications (like Google Maps, Gmail for iPhone and Cisco's WebEx on iPad and several others that use Software as a Service model) but the trend is highly increasing.The main purpose of the paper is to present the methodologies for developing classic enterprise application versus mobile applications. …

Content Centric Networking (CCN), a future Internet architecture, brings new challenges in maintaining the Quality of Experience (QoE) for video streaming. Because of the universal caching capability of CCN routers, streaming from multiple sources will be common, and switching between content sources might affect QoE by inducing delays and consequently stalls in video playback. This paper proposes a new QoE-aware multi-source video streaming scheme for CCN. First, the content distributions of video files among CCN nodes for different caching methods are studied. Second, an adaptive video streaming with distributed caching (ASDC) algorithm is designed to guarantee QoE during the switching between content sources. The ASDC algorithm considers the delivery of scalable video streams. It automatically adapts the layers in a video stream when there is source switching, based on a QoE model that characterizes the effect of stalling. Experimental results show that the ASDC algorithm outperforms dynamic adaptive streaming over HTTP (DASH) in the CCN platform in terms of the QoE obtained from human subjective tests.

Video streaming services using Transmission Control Protocol (TCP) as a transport layerprotocol---represented by YouTube---are becoming increasingly popular and,accordingly, have come to account for asignificant portion of Internet traffic. TCP is greedy; that is, it tries to exhaust theentire bandwidth.Thus, video streaming over TCP tends to unnecessarilytake bandwidth from competing traffic. In this paper, we first investigate the data transfer mechanisms of the currentvideo streaming services using TCP and showthat they perform data transfer at much higher rates than the video playback rate.We then propose a new transfer mechanism for video streaming over TCP,one that controls the data transfer ratebased on the network congestion level and the amount of buffered video data at the receiver.Simulation results show that the proposed mechanism has two characteristics lacked bycurrent video streaming over TCP, specifically (1) a low frequency of buffer underflow at the receiverand (2) a lack of excessive bandwidth ``stealing'' from competing traffic.

Video streaming over wireless (networks) has gained popularity in recent times with the development of 3G and 4G mobile networks. The demand and market for video based services is expected to grow substantially in the future. When UDP is used for video streaming, the inherent unreliability of UDP frequently results in corrupted video packets and jitter during video playback. Such an aberration is especially pronounced in wireless networks due to the fading and multipath interference impediments in wireless channels. TCP based video transmission provides reliability at the cost of severely increased delay arising from frequent retransmissions in case of packet error over wireless links and constraints from session and application layers for in-sequence delivery. These delays are substantially worsened in low SNR (signal-to-noise power ratio) wireless environments. Multiple TCP connections, which efficiently utilize the bandwidth of the wireless channel, have been demonstrated to yield significantly improved quality of video streaming over wireless channels while enhancing the reliability of video delivery compared to UDP. In this paper we propose a new scalable hierarchical wavelet decomposition based layered video coding over parallel TCP scheme for reliable video transmission over MIMO wireless channels while reducing the delay and jitter of video streaming.

This paper introduces iFringe, a mobile application that attempts to incorporate the resource heavy fringe analysis algorithms into the smart mobile devices platform. This first step taken towards mobility in the optical processing field aims to become a catalyst for modernization of various aspects of the field as well as to diversify developments to other applications. Predominantly, the motivation of this work stems from the vastly indifferent human interactive method of mobile devices, which enable images displayed on its touch screen to be manipulated in ways that could enhance the fringe analysis experience. Furthermore, given its hardware compatibility to the conventional fringe projection system, these mobile devices could potentially serve as a much more compact replacement. However, one imperative weakness that mobile devices pose is its limited computing ability. Therefore, to examine the feasibility of incorporating the fringe analysis algorithms into a mobile platform, we have implemented two fundamental fringe analysis techniques, namely the Fourier transform fringe analysis method and the phase-shifting technique. Formulas and processing procedures such as discrete Fourier transform (DFT) and quality-guided phase unwrapping, were included in accordance to their original algorithms to test their performance and usability on a smart mobile device. Details of the implementation and the performance results will also be presented in this paper to demonstrate the practicality of these algorithms on the smart mobile device platform.

Mobile devices are becoming increasingly common place among users, particularly corporate personnel. The Mobile devices pose a greater danger to corporate security than PCs according to their larger attack surface. Mobiles are used by individuals and enterprises for a variety of purposes including planning and organizing professional life. This led to significantly altering how information systems and Mobile applications are structured, consequently, Cyber Security safeguards all data on Mobiles, other computing and network devices. Raising awareness about Mobile security threats and recommended practices has become a primary focus due to the continuous emergence of new vulnerabilities in Mobile devices. There is an emergency need to adopt approaches and best practices to secure Mobiles, computing devices and their connected networks to defence against threats and attacks. To address these significant challenges, this paper aims to identify and describe in details the well-known Mobile threats and attacks. The paper recommends a set of Mobile security best practices that were suggested for Mobile users and organizations to secure their mobile devices against different types of threats and attacks.

Remote screen recording is a system that records whole actions on a remote computer screen, and displays the actions on a client computer screen at the same time. Traditionally, screen recording are streamed in a video format, which large data usually results in high CPU utilization and heavy network loading. Therefore, in order to reduce CPU utilization and network bandwidth loading, the screen recording system records and only sends the blocks which have updates on the recording screen. A screen update on any part of the recording screen is called a "changed block" in this paper. Only recording and sending the changed blocks definitely reduces the network bandwidth and CPU loading. Because of only sending changed blocks, this study comes up with a media synchronization problem between a video stream and remote screen data stream in a distance learning system due to an unstable network environment. This study proposes a fast skip mechanism, called Fast Media Synchronization (FMS), to match the video stream playback by adjusting the remote screen data stream. The FMS quickly determines whether the changed blocks overlap. In the fast skip mechanism of FMS, overlapping areas among changed blocks in a screen data stream will be effectively deleted. In this paper, four different scenarios web browsing, document editing, slide presentation, and video playback, are designed to test the effectiveness of applying FMS. The experiment results shows that the FMS mechanism approximately reduces 85% of processing time, 57% to 99% of the frequency of pasting times, 70% to 90% the number of comparisons, and 70% to 90% the total pasting area. Furthermore, the proposed FMS mechanism can also be applied to improve the efficiency of different screen recording systems, such as remote desktop, distance conferencing, and video streaming, etc.