VoltDB and IBM Present: The Key to Unlocking the Economic Value of Fast Data in the Cloud
Service Virtualization —Increase Test Environment Reliability
Revisiting Amplify-and-Forward Relaying in Cooperative Communications and Underlay Cognitive Radio
Abstract of the talk: Relay-assisted cooperative communications exploits spatial diversity to combat wireless fading, and is an appealing technology for next generation wireless systems. In amplify-and-forward (AF) relaying, the relay amplifies the signal it receives from the source and forwards it to the destination. AF relaying is considered to be simple to implement since the relay does not need to decode the received signal. While different variants of AF relaying have been extensively investigated in the literature, we argue in this talk that they are ad hoc and sub-optimal as they restrict the relay’s gain or transmit power. To this end, we first develop a novel and optimal AF relay gain adaptation policy for a two-hop relay system. In this, an average power-constrained relay adapts its gain and transmit power to minimize the fading-averaged symbol error probability (SEP) at the destination. Second, we generalize the above policy and apply it to underlay cognitive radio, which is a mode of access that promises to ease the severe spectrum crunch currently faced by wireless systems. In this generalization, we determine how the AF relay should optimally adapt its gain as a function of its local channel gains to the secondary source, secondarydestination, and primary receiver so as to satisfy a constraint on the average interference it causes to the primary receiver.
IEEE CASS-CS Delhi Section Lecture Series
*Lecture 1: Prof. Radu Marculsecu, Carnegie Mellon University* *Time: 2:00-3:00 PM* *Title: Entering the Labyrinth of (Inexact) Computer Science: A Cyber-Physical Approach* *Abstract*: During high school, I was fascinated by science. I used to read stories about Nobel Prize laureates and dream about their discoveries. Despite this, I became an engineer and, over the years, got to appreciate the power and transformative nature of computing in all human endeavors. In recent years, due to the cyber-physical systems (CPS) advent, I have found renewed interest and (somehow unexpected) opportunities to revisit some long forgotten topics in math and physics realizing that they can actually offer a much deeper understanding of CPS modeling and optimization. Truth being told, designing cyber-physical systems still feels more like an art rather than science but, in order to harness their huge potential, we need to reach beyond the established confines of computer systems design and (re)define a new science of CPS design. Starting from these overarching ideas, I discuss the theoretical foundations and practical implications of using a communication-centric approach to developing new mathematical models and tools needed to guide the CPS optimization ranging from hardware, to dense networks of interacting bacteria and to quorum quenching in pathogen networks. In other words, this talk is precisely about the subtle interplay between science and engineering and the joy of seeing things come full circle. Speaker Bio: Dr. Radu Marculescu is a Professor in the Dept. of Electrical and Computer Engineering at Carnegie Mellon University, USA. He received his Ph.D. in Electrical Engineering from the University of Southern California in 1998. He has received several best paper awards in the area of design automation and embedded systems design. He has been involved in organizing several international symposia, conferences, workshops, as well as guest editor of special issues in archival journals and magazines. His research focuses on modeling and optimization of embedded systems, cyber-physical systems, and biological systems. Radu Marculescu is a Fellow of IEEE. ************************************************************************************************ *Lecture 2: Prof. Partha Pratim Pande, Washigton State University* *Time: 3:00-4:00 PM* *Title: Wireless NoC as Interconnection Backbone for Multicore Chips: Promises and Challenges* Abstract: The continuing progress and integration levels in silicon technologies make complete end-user systems on a single chip possible. This massive level of integration makes modern multi-core chips all pervasive in domains ranging from weather forecasting, astronomical data analysis, and biological applications to consumer electronics and smart phones. NoCs have emerged as communication backbones to enable a high degree of integration in multi-core SoCs. Despite their advantages, an important performance limitation in traditional NoCs arises from planar metal interconnect-based multi-hop communications, wherein the data transfer between far-apart blocks causes high latency and power consumption. The latency, power consumption, and interconnect routing problems of NoCs can be simultaneously addressed by replacing multi-hop wired paths with high-bandwidth single-hop long-range wireless links. In this talk, we will present an overview of the various wireless NoC (WiNoC) architectures proposed so far designed in traditional 2D IC substrate. After this, we introduce how high bandwidth and low power WiNoC architectures can be designed by incorporating the small-world architecture. We will present detailed performance evaluation and necessary design trade-offs for the small-world WiNoCs with respect to their conventional wireline counterparts. We will also discuss different media access control (MAC)mechanisms