A study of the suitability of videophones for psychometric assessment

In order to determine whether videophones are appropriate communication tools for psychometric assessments, we need to determine whether the quality of videophones is adequate to enable this type of assessment or whether it places a burden on the communication. The purpose of this study is to measure the subjective quality of video and audio features of commercially available videophones in the context of a psychometric assessment session. We recruited 52 subjects who used the videophone to participate in a psychometric assessment using the Perceived Stress Scale. After each session, participants filled out the ITU-T P.920 that assesses the context-specific quality of the video-call. Findings indicate that the overall audio and image quality of the video-call was satisfactory and participants perceived the videophones as useful in the context of psychometric assessment. These findings strengthen the call for use of video mediated communication in home and hospice settings and disease management.     

Real faces and robot faces: The effects of representation on computer-mediated communication

While there is much research regarding audio, video and text based communication, there has been little work concerning how users communicate via avatars—that is graphical embodiments of remote users. The aim of this study was to explore the effects of different forms of representation, by examining how users communicate via high quality video images and basic graphical representations in different communicative contexts. Communication analysis revealed that video images facilitate turn-taking, although they are not necessarily perceived very differently from basic avatars in terms of questionnaire responses. Using eye-tracking techniques, we found that while participants generally gaze more often at video images, this is dependent on the communicative context and is not necessarily an advantage in a problem-solving situation. This study has demonstrated the value of employing various measures and tasks in order to evaluate computer-mediated interactions. The results have implications for the use of video and graphical representations in computer mediated communication and suggest that the benefits of video must be considered in relation to the user's requirements (e.g. communication process versus outcome) and context in which the system is to be applied (e.g. problem-solving or social).     

User models of subjective image quality assessment on virtual viewpoint in free-viewpoint video system

In this paper, we present a user model of subjective quality assessment on virtual viewpoint image (VVI) for free-viewpoint video system. VVIs are rendered through neighbor viewpoint color and depth images, and it is a new type of image that generated for human-computer interaction (HCI) in free-viewpoint video system. In this system, a natural scene is captured by multi-viewpoint cameras, and users can view the scene from any desired viewpoint, regardless the real or virtual one. The subjective quality of VVIs is crucial for the quality of experiences for HCI, because the magnitude of VVI is much greater than the real. In order to find the user model of VVI quality assessment, we organize three sets of stimuli, including Symmetric Stimuli, Asymmetric Stimuli Part I and Part II, to reveal the psychological responses of participants. A psychometric function is consequently obtained to determine the relationship between stimulus and psychological responses. Further discussions on the factors of distortion level, gender, age and academic background are examined to find the influence on the user model. We find that the distortion level of neighbor viewpoint color images has the dominant impact on the user model, while other factors contribute little.     

Contribution of display size to speech intelligibility in videophone systems

Widespread use of videophones has been limited due to cost factors and human factors. If demands for image size and quality were relaxed while preserving the communicational value added by visual data, low end videophones may become feasible. After a review of pertinent research, we describe an experiment indicating modest visual augmentation significantly aids speech intelligibility. The results suggest several directions for further research.     

移动智能终端安全即时通信方法

针对移动智能终端即时通信安全问题,提出了一种不可信互联网条件下移动智能终端安全通信方法。该方法设计并实现了一种在服务器和通信信道均不可信情况下的可信密钥协商协议。理论分析表明,所提出的密钥协商协议可以确保通信双方所协商会话密钥的真实性、新鲜性和机密性等诸多安全特性。密钥协商完成之后,基于透明加解密技术即可以确保即时通信双方语音/视频通信信息的机密性和完整性。真实移动互联网环境下的测试也表明该方法是高效和安全的,密钥协商可以在1~2 s完成,攻击者无法获取即时通信的明文信息。     

Automatic prediction of perceptual quality of multimedia signals—a survey

We survey recent developments in multimedia signal quality assessment, including image, audio, video, and combined signals. Such an overview is timely given the recent explosion in all-digital sensory entertainment and communication devices pervading the consumer space. Owing to the sensory nature of these signals, perceptual models lie at the heart of multimedia signal quality assessment algorithms. We survey these models and recent competitive algorithms and discuss comparison studies that others have conducted. In this context we also describe existing signal quality assessment databases. We envision that the reader will gain a firmer understanding of the broad topic of multimedia quality assessment, of the various sub-disciplines corresponding to different signal types, how these signals types co-relate in producing an overall user experience, and what directions of research remain to be pursued.     

新型三方口令认证密钥协商协议的安全性分析与改进

口令认证密钥协商(PAKA)是认证密钥协商(AKA)中的重要分支之一。研究了一种新型三方口令认证密钥协商--3REKA的安全性,发现如果参与双方的验证值丢失,将导致严重的中间人攻击,这一攻击的结果是敌手可以与参与者各自建立独立的会话密钥。描述了这一攻击,并对原协议进行了改进,提出了I-3REKA协议。安全性和性能分析表明,所提出的协议以较低的计算量实现了参与双方的安全通信。     

The development of a sound viewer for an open hypermedia system

Abstract

While rich support for a wide variety of media such as text, video and image is common among contemporary hypermedia systems, so too is the inadequate support for audio. The primary reason that audio has not attracted as much attention as other media can be attributed to its obvious lack of visual identity. The main focus of this work was to identify a generic and meaningful visual representation of audio within a hypermedia context, and significantly promote hypermedia support for audio through the provision of a sound viewer.

This paper describes the inherent difficulties in providing a consistent interface to audio, and discusses in some depth the issues raised during the development process. The sound viewer is then introduced and the associated concepts described. The creation and traversal of links to and from audio are facilitated by the sound viewer across formats including WAV (proprietary digital sound file format from Microsoft), CD (Compact Disc) Audio and MIDI (Musical Instrument Digital Interface). The resultant viewer provides a unified and extensible framework for interacting with audio from within an open hypermedia environment. The open hypermedia system Microcosm was used as the development platform for this work. Microcosm can be augmented to supply a hypermedia link service to additional media with minimal overhead.     

Partial encryption and watermarking scheme for audio files with controlled degradation of quality

With the rapid progress in communication and multimedia technology, protection of multimedia assets has become a major concern. Encryption and watermarking are two complementary techniques that are used for safeguarding multimedia data like audio, video and images. These methods serve two different purposes; encryption helps in making the media unintelligible, while watermarking helps in providing copyright information in it. In this paper a combination of both encryption and watermarking is incorporated on audio files with this aim in view. Discrete Wavelet Transformation (DWT) is performed on audio files up to third level which gives rise to a binary tree like structure. The areas for watermark embedding and encryption are selected among the wavelet coefficients in the leaf nodes of the tree. Detailed experimentation is carried out with analysis of SNR values, that leads to the determination of degree of degradation of the audio quality after encryption. Such controlled degradation can be used for safe distribution of audio contents over public networks, whereby only the authorized users can have access to the high quality contents, while other users can only access a lower quality version.     

基于WebRTC技术的诊后医疗系统实时通信研究

WebRTC技术的出现提出了实时音视频处理的解决方案,所具有的开放标准为研究实时音视频的处理流程提供了技术依据.通过对WebRTC的核心音视频操作库进行研究,将WebRTC的技术方案应用于诊后医疗系统的在线问诊模块,用以提升线上问诊服务的音视频质量.通过对实时通信进行研究并依托WebRTC协议的通信体系结构,设计了信令和媒体代理方案并最终实现了诊后医疗系统的实时通信.     

Video games as virtual teachers: Prosocial video game use by children and adolescents from different socioeconomic groups is associated with increased empathy and prosocial behaviour

ObjectiveThe main aim of this study was to determine if there was a positive relationship between prosocial video game use and prosocial behaviour in children and adolescents.MethodThis study had a cross-sectional correlational design. Data were collected from 538 9–15 year old children and adolescents between March and December 2014. Participants completed measures of empathy, prosocial behaviour and video game habits. Teachers rated the prosocial behaviour of participants. The socioeconomic status of participants was also gathered.ResultsMultiple linear regressions were conducted on these data. Prosocial video game use was positively associated with the tendency to maintain positive affective relationships, cooperation and sharing as well as empathy. This association remained significant after controlling for gender, age, school type (disadvantaged/non-disadvantaged), socioeconomic status, weekly game play and violent video game use.ConclusionsThese findings provide evidence that prosocial video game use could develop empathic concern and improve affective relationships in a diverse population of young people.     

A steganographic method based on optimized audio embedding technique for secure data communication in the internet of things

The rapid growth of the internet and the internet of things (IoT) refers to the next phase of information revolution whose context involves billions of smart devices and sensors interconnected to facilitate speedy information and data exchange under soft real-time constraints. Digital information revolution has caused significant changes in the data communication. This data communication may require private, secure, and sometimes malicious communication. Competent secrecy can be accomplished by applying novel and inventive audio steganography. This article focuses on the secret message followed by shuffled embedded bit substitution in original audio stream by adopting optimized audio embedding technique (OAET) from the technological observation. To hide the information in the deeper layer of the audio stream, this method uses a new elevated bit range least significant bit (LSB) audio steganography technique that decreases distortion and improves the robustness of the embedded audio stream. The proposed technique proves that the perceptual quality of audio steganography is better than the previous standard LSB technique. Experiment results proved that the cladding of the OAET provides high-level security to the universal cyber data. The interpretation of results shows that embedding data in audio enhances the level of security when used as IoT smart speakers, where the attackers could not distinguish between the original audio and the embedded audio streams.     

Real‐time multicast tree visualization and monitoring

The exponential growth of the Internet combined with the increasing popularity of streaming audio and video are pushing Internet bandwidth constraints to their limits. Methods of managing and more efficiently utilizing existing bandwidth are becoming increasingly vital. Using IP multicast to deliver content, especially streaming audio and video, can provide enormous bandwidth savings. A decade of effort at deploying multicast, combined with the rising need for better traffic management for bandwidth‐hungry applications has led to significant momentum for multicast use and deployment. One of the remaining barriers to widespread adoption is the lack of multicast monitoring and debugging tools. To address this need we introduce MHealth, a graphical, near real‐time multicast monitoring tool. MHealth utilizes existing tools to collect comprehensive data about Realtime Transport Protocol (RTP) based streaming audio/video sessions. By using a combination of application‐level protocol data for participant information and a multicast route tracing tool for topology information, MHealth is able to present a multicast tree's topology and information about the quality of received data. In this paper we describe the design and implementation of MHealth and include an example analysis of multicast tree statistics. Copyright © 2000 John Wiley & Sons, Ltd.     

Enhancing instructional outcomes with gamification: An empirical test of the Technology-Enhanced Training Effectiveness Model

BackgroundGamification, the use of game elements in non-game contexts, has become a popular technique to improve instructional outcomes in both organizational and educational contexts. In the organizational context, the Technology-Enhanced Training Effectiveness Model [TETEM] provides a framework to understand how technologies, like gamification, can effect change in various instructional outcomes. Specifically, application of TETEM suggests that gamification may not effect change in instructional outcomes when learner attitudes towards game-based learning and experience with video games are low.MethodIn this study, we test this model in the gamification context by assigning potential learners to read scenarios describing gamified instruction or traditional, PowerPoint instruction in a random order and assessing their training valence.ResultsOn average, participants anticipated greater value from gamified instruction, but as predicted by TETEM, this effect was moderated by both video game experience and attitudes towards game-based learning. Among potential learners with high experience and attitudes, gamification produces better outcomes than PowerPoint, but among potential learners with low experience and attitudes, gamification produces worse outcomes than PowerPoint.ImplicationsWe provide empirical support for TETEM and conclude that for gamification to be successful, the attitudes and experience of participants must be assessed and ensured before gamification is implemented.     

一种基于SIP的交互式高清晰视频会议系统

文中提出一种专门用于远程教育中实时授课的视频会议系统(HDVShow),它采用SIP作为会话控制协议,采用可靠混合组播协议(RCMP)作为多媒体传输协议,可传输1080iHD的教室全场景高清晰视频,完全再现教室中发生的教学活动.RCMP结合了IP组播和应用层组播(ESM)的优点,解决了传统C/S结构带来的服务器负载过重问题.系统采用重传和FEC编码相结合的机制恢复网络传输过程中丢失的视频帧,从而有效改善了网络状况欠佳时的视频质量.实验表明,和传统的视频会议相比, HDVShow在高带宽下能充分利用可用带宽,从而有更高质量的视音频;在低带宽下也可有更加稳定的视音频质量.     

ViComp: composition of user-generated videos

We propose ViComp, an automatic audio-visual camera selection framework for composing uninterrupted recordings from multiple user-generated videos (UGVs) of the same event. We design an automatic audio-based cut-point selection method to segment the UGV. ViComp combines segments of UGVs using a rank-based camera selection strategy by considering audio-visual quality and camera selection history. We analyze the audio to maintain audio continuity. To filter video segments which contain visual degradations, we perform spatial and spatio-temporal quality assessment. We validate the proposed framework with subjective tests and compare it with state-of-the-art methods.     

Combating Viruses on Microcomputers and LANs

ABSTRACT

The HTTP protocol is designed for stateless transactions, but many Web applications require a session to be maintained between a Web browser and a server creating a stateful environment. Each Web application decides how its session is managed and needs to be able to trust the session identifier. However, it is possible for sessions to be hijacked, and an intruder can gain unauthorized access to the hijacked session. The purpose of this paper is to provide an analysis of current session management mechanisms and examine various hijacking techniques. The primary issues that will be addressed pertain to session management and the importance of securing the creation, deletion, and transmission of a session token. We provide a broader view of the session hijacking threat environment by analyzing existing Web application implementations to help demonstrate the need for session hijacking prevention. We will identify the session management areas that are targeted by attackers and will identify and examine various attacks that can lead to a session being hijacked.     

Automatic Segmentation of News Items Based on Video and Audio Features

The automatic segmentation of news items is a key for implementing the automatic cataloging system of news video.This paper presents an approach which manages audio and video feature infomation to automatically segment news items.The integration of audio and visual analyses can overcome the weakness of the approach using only image analysis techniques.It makes the approach more adaptable to various situations of news items.The proposed approach detects silence segments in accompanying audio,and integrates them with shot segmentation results,as ewll as anchor shot detection results,to determine the boundaries among news items,Expeimental results show that the integration of audio and video features is an effective approach to solving the problem of automatic segmentation of news items.     

Private Camera Conversation: a new method for eliciting user responses?

Abstract

This paper discusses a new method called Private Camera Conversation. This method can be used to elicit user opinions on various subjects like their use of products. Initial impressions of the method are given on the basis of three small studies in which the method was employed. The method has not yet been validated and compared with existing human factors methods. This study reports the first findings of the application of the method. With Private Camera Conversation people are invited to talk about a particular topic in private to a video camera. The participants themselves decide when they want to start and when they want to stop the recording session. Initial impressions arc that the method has potential benefits for eliciting rich and useful responses even with respect to ‘personal’ issues. The Private Camera Conversation method seems particularly suitable for obtaining information about the social context in which products are used and about qualitative aspects of product use. The method is inviting and entertaining for participants and easy and effective to carry out. Optimal exploitation of the method has to be realized through further development. We hope this article will be a catalyst for further research.     

A robust method for estimating synchronization and delay of audio and video for communication services

One of the main contributions to the quality of experience in streaming services or in two-way communication of audio and video applications is synchronization. This has been shown in several studies and experiments but methods to measure synchronization are less frequent, especially for situations without internal access to the application and independent of platform and device. In this paper we present a method for measuring synchronization skewness as well as delay for audio and video. The solution incorporates audio and video reference streams, where audio and video frames are marked with frame numbers which are decoded on the receiver side to enable calculation of synchronization and delay. The method has been verified in a two-way communication application in a transparent network with and without inserting known delays, as well as in a network with 5 and 10 % packet loss levels. The method can be used for both streaming and two-way communication services, both with and without access to the internal structures, and enables measurements of applications running on e.g. smartphones, tablets, and laptops under various conditions.