Adaptive Network Coding for Scheduling Real-time Traffic with Hard Deadlines

We study adaptive network coding (NC) for scheduling real-time traffic over a single-hop wireless network. To meet the hard deadlines of real-time traffic, it is critical to strike a balance between maximizing the throughput and minimizing the risk that the entire block of coded packets may not be decodable by the deadline. Thus motivated, we explore adaptive NC, where the block size is adapted based on the remaining time to the deadline, by casting this sequential block size adaptation problem as a finite-horizon Markov decision process. One interesting finding is that the optimal block size and its corresponding action space monotonically decrease as the deadline approaches, and the optimal block size is bounded by the "greedy" block size. These unique structures make it possible to narrow down the search space of dynamic programming, building on which we develop a monotonicity-based backward induction algorithm (MBIA) that can solve for the optimal block size in polynomial time. Since channel erasure probabilities would be time-varying in a mobile network, we further develop a joint real-time scheduling and channel learning scheme with adaptive NC that can adapt to channel dynamics. We also generalize the analysis to multiple flows with hard deadlines and long-term delivery ratio constraints, devise a low-complexity online scheduling algorithm integrated with the MBIA, and then establish its asymptotical throughput-optimality. In addition to analysis and simulation results, we perform high fidelity wireless emulation tests with real radio transmissions to demonstrate the feasibility of the MBIA in finding the optimal block size in real time.Comment: 11 pages, 13 figure

Cellular delivery of antibodies: effective targeted subcellular imaging and new therapeutic tool

It is already more than a century since the pioneering work of the Nobel Laureate Ehrlich gave birth to the side chain theory1, which helped to define antibodies and their ability to target specific biological sites. However, the use of antibodies is still restricted to the extracellular space due to the lack of a suitable delivery vehicle for the efficient transport of antibodies into live cells without inducing toxicity. In this work, we report the efficient encapsulation and delivery of antibodies into live cells with no significant loss of cell viability or any deleterious affect on the cell metabolic activity. This delivery system is based on poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-(2-(diisopropylamino)ethyl methacrylate), (PMPC-PDPA), a pH sensitive diblock copolymer that self-assembles to form nanometer-sized vesicles, also known as polymersomes, at physiological pH. These polymersomes can successfully deliver relatively high antibody payloads within live cells. Once inside the cells, we demonstrate that these antibodies can target their epitope by immune-labelling of cytoskeleton, Golgi, and transcription factor proteins in live cells. We also demonstrate that this effective antibody delivery mechanism can be used to control specific subcellular events, as well as modulate cell activity and pro-inflammatory process

Effect of Sequence of Simulated and Clinical Practicum Learning Experiences on Clinical Competency of Nursing Students

Two different sequences of blocks of simulated and clinical practicum learning experiences compared the clinical competency development of nursing students using a randomized crossover design. Competency was measured 3 times: after each block of simulated and clinical experiences and after a final simulated experience. No significant differences in competency scores between the 2 groups across the 3 time points were found. Using alternative models of clinical and simulation learning may help address barriers to the delivery of clinical education faced by schools of nursin

Beyond the Min-Cut Bound: Deterministic Network Coding for Asynchronous Multirate Broadcast

In a single hop broadcast packet erasure network, we demonstrate that it is possible to provide multirate packet delivery outside of what is given by the network min-cut. This is achieved by using a deterministic non-block-based network coding scheme, which allows us to sidestep some of the limitations put in place by the block coding model used to determine the network capacity. Under the network coding scheme we outline, the sender is able to transmit network coded packets above the channel rate of some receivers, while ensuring that they still experience nonzero delivery rates. Interestingly, in this generalised form of asynchronous network coded broadcast, receivers are not required to obtain knowledge of all packets transmitted so far. Instead, causal feedback from the receivers about packet erasures is used by the sender to determine a network coded transmission that will allow at least one, but often multiple receivers, to deliver their next needed packet. Although the analysis of deterministic coding schemes is generally a difficult problem, by making some approximations we are able to obtain tractable estimates of the receivers' delivery rates, which are shown to match reasonably well with simulation. Using these estimates, we design a fairness algorithm that allocates the sender's resources so all receivers will experience fair delivery rate performance

A novel H.264 SVC encryption scheme for secure bit-rate transcoding

This paper presents a novel architecture for the secure delivery of encrypted H.264 SVC bitstreams. It relies on a block cipher and stream cipher used in a novel way that would allow an intermediary transcoder to truncate the bitstream to the appropriate bit-rate without decrypting the data. The system, called SVC-sec, is compared to other architectures presented in the literature and it is shown that SVC-sec offers many benefits, particularly when used with FGS streams.This paper presents a novel architecture for the secure delivery of encrypted H.264 SVC bitstreams. It relies on a block cipher and stream cipher used in a novel way that would allow an intermediary transcoder to truncate the bitstream to the appropriate bit-rate without decrypting the data. The system, called SVC-sec, is compared to other architectures presented in the literature and it is shown that SVC-sec offers many benefits, particularly when used with FGS stream

Supramolecular anticancer drug delivery systems based on linear–dendritic copolymers

Current cancer chemotherapy often suffers severe side-effects of the administered cancer drugs on the normal tissues. In addition, poor bioavailability, due to the low water solubility of the anticancer drugs, limits their applications in chemotherapy. New delivery technologies could help overcome this challenge by improving the water solubility and achieving the targeted delivery of the anticancer drugs. Linear–dendritic hybrid nanomaterials, which combine the highly branched architectures and multifunctionality of dendrimers with the processability of traditional linear–linear block copolymers, have been introduced as ideal carriers in anticancer drug delivery applications. This review presents recent advances in the investigational aspects of linear–dendritic copolymers to be applied as anticancer drug delivery vehicles. We highlight the structures, synthesis of linear–dendritic block copolymers, interaction mechanisms between linear–dendritic copolymers and anticancer drug molecules, and findings on their drug release behavior and anticancer efficacies in vitro and in vivo