Capacity of wireless erasure networks

In this paper, a special class of wireless networks, called wireless erasure networks, is considered. In these networks, each node is connected to a set of nodes by possibly correlated erasure channels. The network model incorporates the broadcast nature of the wireless environment by requiring each node to send the same signal on all outgoing channels. However, we assume there is no interference in reception. Such models are therefore appropriate for wireless networks where all information transmission is packetized and where some mechanism for interference avoidance is already built in. This paper looks at multicast problems over these networks. The capacity under the assumption that erasure locations on all the links of the network are provided to the destinations is obtained. It turns out that the capacity region has a nice max-flow min-cut interpretation. The definition of cut-capacity in these networks incorporates the broadcast property of the wireless medium. It is further shown that linear coding at nodes in the network suffices to achieve the capacity region. Finally, the performance of different coding schemes in these networks when no side information is available to the destinations is analyzed

On the capacity of wireless erasure networks

We determine the capacity of a certain class of wireless erasure relay networks. We first find a suitable definition for the "cut-capacity" of erasure networks with broadcast at transmission and no interference at reception. With this definition, a maxflow mincut capacity result holds for the capacity of these networks

Poset belief propagation-experimental results

Poset belief propagation, or PBP, is a flexible generalization of ordinary belief propagation which can be used to (approximately) solve many probabilistic inference problems. In this paper, we summarize some experimental results comparing the performance of PBP to conventional BP techniques

Kinematics of Spherical Robots Rolling Over 3D Terrains

Although the kinematics and dynamics of spherical robots (SRs) on flat horizontal and inclined 2D surfaces are thoroughly investigated, their rolling behavior on generic 3D terrains has remained unexplored. This paper derives the kinematics equations of the most common SRs configurations rolling over 3D surfaces. First, the kinematics equations for a geometrical sphere rolling over a 3D surface are derived along with the characterization of the modeling method. Next, a brief review of current SR mechanical configurations is presented as well as a novel classification for spherical robots based on their kinematics. Then, considering the mechanical constraints of each category, the kinematics equations for each group of spherical robots are presented. Afterwards, a path tracking method is utilized for a desired 3D trajectory. Finally, simulations are carried out to validate the developed models and the effectiveness of the proposed control scheme

Spinal codes

Spinal codes are a new class of rateless codes that enable wireless networks to cope with time-varying channel conditions in a natural way, without requiring any explicit bit rate selection. The key idea in the code is the sequential application of a pseudo-random hash function to the message bits to produce a sequence of coded symbols for transmission. This encoding ensures that two input messages that differ in even one bit lead to very different coded sequences after the point at which they differ, providing good resilience to noise and bit errors. To decode spinal codes, this paper develops an approximate maximum-likelihood decoder, called the bubble decoder, which runs in time polynomial in the message size and achieves the Shannon capacity over both additive white Gaussian noise (AWGN) and binary symmetric channel (BSC) models. Experimental results obtained from a software implementation of a linear-time decoder show that spinal codes achieve higher throughput than fixed-rate LDPC codes, rateless Raptor codes, and the layered rateless coding approach of Strider, across a range of channel conditions and message sizes. An early hardware prototype that can decode at 10 Mbits/s in FPGA demonstrates that spinal codes are a practical construction.Massachusetts Institute of Technology (Irwin and Joan Jacobs Presidential Fellowship)Massachusetts Institute of Technology (Claude E. Shannon Assistantship)Intel Corporation (Intel Fellowship

Chronic myeloid leukemia on imatinib with recurrent sub-dural haemorrhage

Imatinib is an FDA approved first-line treatment for Philadelphia-positive CML. It is a selective tyrosine kinase inhibitor specifically targeting BCR-ABL, c-KIT, PDGFRA. It has been reported with low incidence of adverse effects and high tolerability, with haemorrhagic events being a rare complication. We report here a case of 51-year-old female patient with chronic myeloid leukemia who was on high dose imatinib experienced recurrent sub-dural haemorrhage. This case report emphasizes on the need to consider Sub dural haemorrhage as an unusual cause of headache associated with vomiting in a patient taking high dose of imatinib

Robust nonlinear state feedback under structured uncertainty

This work follows the global input/output linearization approach for the design of control systems for nonlinear plants of Kravaris and Chung. A robust nonlinear state feedback is proposed for uncertainties considered as a class of bounded perturbations to the state model. A Liapunov-based approach is used to guarantee uniform ultimate boundedness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37402/1/690340708_ftp.pd

Dynamic Optimization of Batch Processes: I. Characterization of the Nominal Solution

LABest Paper of the Year Awar