The authors survey existing solutions to adaptive video multicast, providing a taxonomy of solutions according to several distinct features. They also review the principal techniques from both video coding and network transport perspectives. Finally, they discuss the evaluation methodologies and metrics for adaptive video multicast systems.
Video simulcasting enables a sender to generate multiple streams for the same video program but at different rates, targeting receivers of different capacities. Each stream is then distributed to the target receivers via broadcast or multicast channels. A key design issue of video simulcasting is how to strike a balance between bandwidth economy (as stream replication introduces redundancy) and user satisfaction (as there is a mismatch between a receiver's capacity and the limited choice of the stream rates). This paper presents a formal study on the above problem in a rate-limited network; specifically, given a session bandwidth budget, what is the optimal number of streams that should be generated and what is the optimal rate that should be allocated to each stream? We also derive efficient algorithms to solve these two problems with the objective of minimizing the expected bandwidth mismatch for all the receivers.
With the convergence of wired line Internet and mobile wireless networks, it's important to study its impacts on continuous media delivery and media streaming protocols. In this paper, we propose an end-to-end (wireless) multimedia streaming TCP-friendly protocol for media delivery over wireless Internet (WMSTFP). WMSTFP can effectively differentiate erroneous packet losses from congestive losses and filter out the abnormal round-trip-time values due to the highly varying wireless environment. Analytical and simulation results show that WMSTFP can achieve higher throughput in wireless Internet and can perform rate adjustment in a smooth and TCP-friendly manner.
Objective To understand the current intangible environment of Shanghai higher education institutions from students perspective and to analyze its influential factors. Methods The 1 600 undergraduate students from five higher education institutions, including two 985 universities and three ordinary universities, were surveyed by questionnaires. The questionnaires covered their perceptions towards the intangible environment of universities, which consisted of five aspects: education concept, academic atmosphere, learning atmosphere, campus life, and social practice. Then 1 246 valid questionnaires were returned. Results The results demonstrated that the average score of the intangible environment of Shanghai higher education institutions was above the average level( 3. 43 ± 0. 71). Among all aspects, the social practice gained the highest score( 3. 72 ± 0. 82), while the education concept got the lowest score( 3. 21 ± 0. 84). The evaluation scores of the intangible environment varied among students with different personal characteristics. The average score of academic atmosphere rated by junior students was higher than that rated by sophomores( P 0. 01). Compared to male students, the female students rated higher scores on social practice and academic atmosphere of their universities( P 0. 05). The total average score and all aspects scores of the university environment that rated by student cadres were significant higher than those rated by the rest students( P 0. 05). Moreover, the intangible environment scores of 985 higher education institutions were significant higher than other institutions' scores. Conclusion The students gave positive feedbacks for the intangible environment of Shanghai universities. But higher education institutions should further improve their environments.
Due to such features as low cost, ease of deployment, increased coverage, and enhanced capacity, multihop wireless networks such as ad hoc networks, mesh networks, and sensor networks that form the network in a self-organized manner without relying on fixed infrastructure is touted as the new frontier of wireless networking. Providing efficient quality of service (QoS) support is essential for such networks, as they need to deliver real-time services like video, audio, and voice over IP besides the traditional data service. Various solutions have been proposed to provide soft QoS over multihop wireless networks from different layers in the network protocol stack. However, the layered concept was primarily created for wired networks, and multihop wireless networks oppose strict layered design because of their dynamic nature, infrastructureless architecture, and time-varying unstable links and topology. The concept of cross-layer design is based on architecture where different layers can exchange information in order to improve the overall network performance. Promising results achieved by cross-layer optimizations initiated significant research activity in this area. This paper aims to review the present study on the cross-layer paradigm for QoS support in multihop wireless networks. Several examples of evolutionary and revolutionary cross-layer approaches are presented in detail. Realizing the new trends for wireless networking, such as cooperative communication and networking, opportunistic transmission, real system performance evaluation, etc., several open issues related to cross-layer design for QoS support over multihop wireless networks are also discussed in the paper.
In this paper, the operation of MPEG-2 systems is modeled and simulated when an MPEG-2 transport stream is delivered through a ATM network with jitter. A novel approach to analyzing the decoder buffer behavior in the presence of network jitter is presented. The probability density function of the interarrival time of the ATM adaptation layer 5 (AAL5) Protocol Data Unit (PDU) is derived from a MPEG-2 video source model and an ATM network jitter model. Based on a real-time decoding requirement of the MPEG-2 transport stream (TS) system target decoder (T-STD), the decoder buffer behavior is simulated. The modeling; and simulation results show that jitter affects decoder buffer size and packet loss ratio in a significant way.
Abstract As part of the NIH Helping to End Addiction Long-term (HEAL) Initiative, the National Center for Advancing Translational Sciences (NCATS) is dedicated to the development of new pharmacological tools and investigational drugs for managing and treating pain, as well as the prevention and treatment of opioid misuse and addiction. In line with these objectives, we created a comprehensive, annotated small molecule library including drugs, probes, and tool compounds that act on published pain and addiction-relevant targets. Nearly 3,000 small molecules associated with approximately 200 known and hypothesized HEAL targets have been assembled, curated, and annotated in one collection. Physical samples of the library compounds have been acquired and plated in 1536-well format, enabling rapid and efficient high throughput screen (HTS) against a wide range of assays. The creation of the HEAL Targets and Compounds Library, coupled with an integrated computational platform for AI-driven machine learning (ML), structural modeling, and virtual screening (VS), provides a valuable source for strategic drug repurposing, innovative profiling, and hypothesis testing of novel targets related to pain and opioid use disorder (OUD). The library is available to investigators for screening pain and OUD-relevant phenotypes.
The homogeneity and uniformity of static data storage and access make data leakage one of the most severe security threats. Dynamic data techniques such as data randomization and diversification, are effective approaches to mitigate data theft and illegal data modification. By increasing data diversity and dynamics, the data attack surface shifting space can be expanded to confuse attackers and influence their further actions. However, there are only a few dynamic data techniques developed because of the difficulty in encoding multiple data formats and the loss of compatibility in data formats. In this paper, we propose a new dynamic data approach that integrates the data deception techniques based on Moving Target Defense (MTD). By changing the data size, data authenticity, and users' data access privilege, the approach significantly expands the data attack surface shifting space. Moreover, the approach provides dynamic data access based upon both users' attributes and users' operations. Through dynamic analysis and experiments, the paper shows that the proposed dynamic data technique can expand the attack surface shifting space at a lower cost, protect the sensitive data, and impose no significant burden on the system.
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