Proxy sip/rtp/rtcp a supporto della mobilita: Architettura

Proxy SIP per garantire la comunicazione tra due host

Proxy sip/rtp/rtcp a supporto della mobilita: Prestazioni.

Scenario VoIP, tecnologia PjSip e descrizione dell'implementazione di un Proxy Relay per la soluzione di alcune problematiche SIP

基于JMF的跨平台视频点播系统的设计与实现

利用Java媒体框架(JMF)开发的视频点播系统具有开发简单、跨平台、提供QoS保证和交互性好等优点,具有广泛的应用前景.介绍了JMF应用编程接口的特点和结构,阐述了基于JMF开发的跨平台的视频点播系统的整体结构设计,并详细介绍了基于RTP的实时媒体传输、基于RTCP的拥塞控制、完整VCR操作和穿越NAT等关键技术的具体实现.

基于网络的家庭服务机器人控制系统的研究

随着社会的进步和发展，人们不断追求舒适和安逸的生活，不愿意从事一些枯燥甚至不安全的工作，因此，能够代替人类完成简单工作并可以与人进行沟通的家庭服务机器人越来越受到人们的青睐，有着非常好的应用前景。 家庭服务机器人服务的对象是普通人群，不仅需要为用户提供一种友好、自然的人机交互手段，更为重要的是需要为不同位置、不同环境的人们提供所需求的服务。因此，本文研究的重点在于通过网络和机器人技术开发能够满足人们目前生活要求的基于网络的机器人控制系统。 本文以新松机器人股份有限公司的“家庭服务机器人项目”为背景，在对传统的机器人网络控制技术分析的基础上，主要从控制和视频两大部分展开研究。在控制部分，如何既能实现机器人的网络控制又能实现本地控制是本部分的主要研究内容。为此，本文采用模块化设计思想，分别对客户端模块、服务器端模块、机器人控制端模块进行了详细分析与设计，并且采用JNI（Java Native Interface）技术解决了不同语言的接口问题。针对如何实现代码的复用性以及扩展性问题上，本文提出了一种Applet-Servlet-Win32DLL-MFCDLL（Dynamic Link Library）模式的新型控制架构，实现了机器人的网络控制和本地控制。在视频部分，如何实现视频图像的实时传输是视频方面研究的重点。本文采用JMF（Java Media Frame）技术及RTP（Real Transport Protocol）/RTCP（Real Transport Control Protocol）协议，分别从视频发送模块、视频接收与播放模块进行了设计，达到了很好的实时效果。并且采用双缓冲、多线程技术解决了视频传输过程存在的闪烁、抖动等问题，通过实验验证了该方法的有效性。 最后，本文对机器人网络控制系统进行了实验验证，运行效果良好，并且在对本课题研究的基础上，对网络时延进行了分析及实验测试，简要分析了解决方案。

A novel nonrepudiable threshold multi-proxy multi-signature scheme with shared verification

Tzeng et al. proposed a new threshold multi-proxy multi-signature scheme with threshold verification. In their scheme, a subset of original signers authenticates a designated proxy group to sign on behalf of the original group. A message m has to be signed by a subset of proxy signers who can represent the proxy group. Then, the proxy signature is sent to the verifier group. A subset of verifiers in the verifier group can also represent the group to authenticate the proxy signature. Subsequently, there are two improved schemes to eliminate the security leak of Tzeng et al.’s scheme. In this paper, we have pointed out the security leakage of the three schemes and further proposed a novel threshold multi-proxy multi-signature scheme with threshold verification.

Stripping Sight Bare : Alison Jones’ ‘Portraits by Proxy’

In this paper I analyse UK artist Alison Jones’ sonic interventions Portrait of the Artist by Proxy (2008), Voyeurism by Proxy (2008) and Art, Lies and Audio Tapes (2009). In Portrait of the Artist by Proxy, Jones – who, due to deteriorating vision, has not seen her reflection in a mirror in years – asks and trusts participants to audio-describe her own image back to her. In Voyeurism by Proxy, Jones asks participants to audio-describe erotic drawings by Gustav Klimt. In Art, Lies and Audio Tapes, Jones asks participants to audio-describe other artworks, such as W.F. Yeames’ And When Did You Last see Your Father?. In these portraits by proxy, Jones opens her image, and other images, to interpretation. In doing so, Jones draws attention to the way sight is privileged as a mode of access to fixed, fundamental truths in Western culture – a mode assumed to be untainted by filters that skew perception of the object. “In a culture where vision is by far the dominant sense,” Jones says, “and as a visual artist with a visual impairment, I am reliant on audio-description …Inevitably, there are limitations imposed by language, time and the interpreter’s background knowledge of the subject viewed, as well as their personal bias of what is deemed important to impart in their description” . In these works, Jones strips these background knowledges, biases and assumptions bare. She reveals different perceptions, as well as tendencies or censor, edit or exaggerate descriptions. In this paper, I investigate how, by revealing unconscious biases, Jones’ works renders herself and her participants vulnerable to a change of perception. I also examine how Jones’ later editing of the audio-descriptions allows her to show the instabilities of sight, and, in Portrait of the Artist by Proxy, to reclaim authorship of her own image.

Disclosure of proxy voting information by Australian managed investment schemes

The US Securities and Exchange Comission requires registered management investment companies to disclose how they vote proxies relating to portfolio securities they hold. The primary purpose of this rule is to enable fund investors to monitor the role of institutional shareholders in the corporate governance practices of public companies. In Australia, despite reform proposals, there are no regulations requiring institutional investors to report proxy voting procedures and practises. There is little evidence of voluntary disclosure of proxy voting by Australian managed investment schemes in equities, indicating that there are costs involved in such disclosure.

Self-proxy agreement and weekly school travel behaviour in a sectarian divided society

Proxy reports from parents and self-reported data from pupils have often been used interchangeably to identify factors influencing school travel behaviour. However, few studies have examined the validity of proxy reports as an alternative to self-reported data. In addition, despite research that has been conducted in a different context, little is known to date about the impact of different factors on school travel behaviour in a sectarian divided society. This research examines these issues using 1624 questionnaires collected from four independent samples (e.g. primary pupils, parent of primary pupils, secondary pupils, and parent of secondary pupils) across Northern Ireland. An independent sample t test was conducted to identify the differences in data reporting between pupils and parents for different age groups using the reported number of trips for different modes as dependent variables. Multivariate multiple regression analyses were conducted to then identify the impacts of different factors (e.g. gender, rural–urban context, multiple deprivations, and school management type, net residential density, land use diversity, intersection density) on mode choice behaviour in this context. Results show that proxy report is a valid alternative to self-reported data, but only for primary pupils. Land use diversity and rural–urban context were found to be the most important factors in influencing mode choice behaviour.

Efficacy of proxy definitions for identification of fatigue/sleep-related crashes : an Australian evaluation

Fatigue/sleepiness is recognised as an important contributory factor in fatal and serious injury road traffic incidents (RTIs), however, identifying fatigue/sleepiness as a causal factor remains an uncertain science. Within Australia attending police officers at a RTI report the causal factors; one option is fatigue/sleepiness. In some Australian jurisdictions police incident databases are subject to post hoc analysis using a proxy definition for fatigue/sleepiness. This secondary analysis identifies further RTIs caused by fatigue/sleepiness not initially identified by attending officers. The current study investigates the efficacy of such proxy definitions for attributing fatigue/sleepiness as a RTI causal factor. Over 1600 Australian drivers were surveyed regarding their experience and involvement in fatigue/sleep-related RTIs and near-misses during the past five years. Driving while fatigued/sleepy had been experienced by the majority of participants (66.0% of participants). Fatigue/sleep-related near misses were reported by 19.1% of participants, with 2.4% being involved in a fatigue/sleep-related RTI. Examination of the characteristics for the most recent event (either a near miss or crash) found that the largest proportion of incidents (28.0%) occurred when commuting to or from work, followed by social activities (25.1%), holiday travel (19.8%), or for work purposes (10.1%). The fatigue/sleep related RTI and near-miss experience of a representative sample of Australian drivers does not reflect the proxy definitions used for fatigue/sleepiness identification. In particular those RTIs that occur in urban areas and at slow speeds may not be identified. While important to have a strategy for identifying fatigue/sleepiness related RTIs proxy measures appear best suited to identifying specific subsets of such RTIs.