vSkyConf: Cloud-assisted Multi-party Mobile Video Conferencing

As an important application in the busy world today, mobile video conferencing facilitates virtual face-to-face communication with friends, families and colleagues, via their mobile devices on the move. However, how to provision high-quality, multi-party video conferencing experiences over mobile devices is still an open challenge. The fundamental reason behind is the lack of computation and communication capacities on the mobile devices, to scale to large conferencing sessions. In this paper, we present vSkyConf, a cloud-assisted mobile video conferencing system to fundamentally improve the quality and scale of multi-party mobile video conferencing. By novelly employing a surrogate virtual machine in the cloud for each mobile user, we allow fully scalable communication among the conference participants via their surrogates, rather than directly. The surrogates exchange conferencing streams among each other, transcode the streams to the most appropriate bit rates, and buffer the streams for the most efficient delivery to the mobile recipients. A fully decentralized, optimal algorithm is designed to decide the best paths of streams and the most suitable surrogates for video transcoding along the paths, such that the limited bandwidth is fully utilized to deliver streams of the highest possible quality to the mobile recipients. We also carefully tailor a buffering mechanism on each surrogate to cooperate with optimal stream distribution. We have implemented vSkyConf based on Amazon EC2 and verified the excellent performance of our design, as compared to the widely adopted unicast solutions.Comment: 10 page

Covid-19 and its impacts on consumer decision-making process

The term "virus" derives from the Latin word for "venom" and refers to a microscopic infectious agent. On the other hand, "corona" is named by its shape to look like a crown ring – the scientists who coined the word coronavirus in 1968 reasoned that the virus they were studying under a microscope resembled a solar corona (Steinmetz, 2020). COVID-19 was introduced when it was first detected in late 2019 and used letters from CO-Rona-VI-rus D-isease (Bhargava, 2020). Corona infections were initially seen as cold in 1965 (Kahn & McIntosh, 2005), which is almost six decades ago. Corona was formerly thought to be a basic, non-fatal virus to human beings until 2002. Before the world witnessed a Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) outbreak in November 2002, it was assumed that this virus mainly infected animals. However, this was proven incorrect. Ten years after that, a new pathogenic coronavirus known as the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) spread throughout the Middle East and caused a pandemic in several countries (Shereen et a., 2020)

Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

Publisher PD

An efficient routing tree construction algorithm with buffer insertion, wire sizing and obstacle considerations

In this thesis, we present a fast algorithm to construct a performance driven routing tree with simultaneous buffer insertion and wire sizing in the presence of wire and buffer obstacles. Recently several algorithms like Ptree, Stree, Sptree, and graph-RTBW have been published addressing the routing tree construction problem. But all these algorithms are slow and not scalable. Here we present an algorithm which is fast and scalable with problem size. The main idea of algorithm is to specify some important high-level features of the whole routing tree so that it can be broken down into several components. We apply stochastic search to find the best specification. Since we need very few high-level features to evaluate a routing tree, the size of stochastic search space is small which can be searched in very less time. The solutions for the components are either pre-generated and stored in lookup tables, or generated by extremely fast algorithms whenever needed. Since, the solutions of the components can be constructed efficiently, we can construct and evaluate the whole routing tree efficiently for each specification. Experimental results show that, for trees of moderate size, our algorithm is at least several hundred times faster than the recently proposed algorithms, Sptree and graph-RTBW, with not much difference in delay and resource consumption

Interconnect optimizations for nanometer VLSI design

textAs the semiconductor technology scales into deeper sub-micron domain, billions of transistors can be used on a single system-on-chip (SOC) makes interconnection optimization more important roughly for two reasons. First, congestion, power, timing in routing and buffering requirements make inter- connection optimization more and more challenging. Second, gate delay get- ting shorter while the RC delay gets longer due to scaling. Study of interconnection construction and optimization algorithms in real industry flows and designs ends up with interesting findings. One used to be overlooked but very important and practical problem is how to utilize over- the-block routing resources intelligently. Routing over large IP blocks needs special attention as there is almost no way to insert buffers inside hard IP blocks, which can lead to unsolvable slew/timing violations. In current design flows we have seen, the routing resources over the IP blocks were either dealt as routing blockages leading to a significant waste, or simply treated in the same way as outside-the-block routing resources, which would violate the slew constraints and thus fail buffering. To handle that, this work proposes a novel buffering-aware over-the- block rectilinear Steiner minimum tree (BOB-RSMT) algorithm which helps reclaim the “wasted” over-the-block routing resources while meeting user-specified slew constraints. Proposed algorithm incrementally and efficiently migrates initial tree structures with buffering-awareness to meet slew constraints while minimizing wire-length. Moreover, due to the fact that timing optimization is important for the VLSI design, in this work, timing-driven over-the-block rectilinear Steiner tree (TOB-RST) is also studied to optimize critical paths. This proposed TOB-RST algorithm can be used in routing or post-routing stage to provide high-quality topologies to help close timing. Then a follow-up problem emerges: how to accomplish the whole routing with over-the-block routing resources used properly. Utilizing over-the- block routing resources could dramatically improve the routing solution, yet require special attention, since the slew, affected by different RC on different metal layers, must be constrained by buffering and is easily violated. Moreover, even of all nets are slew-legalized, the routing solution could still suffer from heavy congestion problem. A new global router, BOB-Router, is to solve the over-the-block global routing problem through minimizing overflows, wire-length and via count simultaneously without violating slew constraints. Based on my completed works, BOB-RSMT and BOB-Router tremendously improve the overall routing and buffering quality. Experimental results show that proposed over-the-block rectilinear Steiner tree construction and routing completely satisfies the slew constraints and significantly outperforms the obstacle-avoiding rectilinear Steiner tree construction and routing in terms of wire-length, via count and overflows.Electrical and Computer Engineerin

Simulation Optimization Studies of Routing and Process Flow Problems

Computer aided simulation is emerging as a powerful tool for numerical analysis and in conducting performance evaluations of complex systems that depend on a multitude of variables. The primary objective in such simulation studies is to gauge the performance of the system under a various constraints and operating conditions. The effects of changing the operating parameter space can thus be analyzed without having to implement costly changes. Simulations are also carried out for the baseline scenarios to verity and validate the basic underlying system model. In this thesis research, two practical problems were studied through numerical modeling, and optimized solutions obtained for both. Optimizing the pick-up and delivery routes using a commercial software tool was the first task. Optimization of a production assembly line using a discrete event simulation tool was the second project that was carried out. The primary objective for the first task was to explore various routing scenarios and determine delivery routes that would minimize the total network mileage, while maintaining the pick-up time slots requested by the clients. A related task was to evaluate the possible advantages of centralizing all routing activity from a single site, instead of the two-hub scenario currently in effect. A total of eight different scenarios were studied as part of this effort. The second task involved optimization of the throughput of a fuel injector plant by placing buffers within the assembly lines for increased productivity