Developing Visualization Tools for an Out-of-Order Execution Simulator

Researchers and students require visualization tools in order to efficiently evaluate microprocessor designs as they run in a simulator. The SimpleScalar toolkit, a popular and versatile program for simulating numerous processors, would benefit from such tools. While some visualization tools have been made before for SimpleScalar, few have yet supported the out-of-order execution simulator, where independent instructions are processed in parallel, out of program order. There are several factors that a designer must assess to develop visualization tools that can run on numerous hardware architectures and operating systems: code portability, the graphical user interface (GUI), and running speed. Code portability refers to the choice of programming language/languages and supported compilers and platforms, which determines the system configuration required to run the software. The design of the graphical user interface determines the effectiveness with which a user can interact with the visualization tool, and the underlying simulator itself. Both of these factors will have an effect o

Measuring Parameter Variation on an FPGA Using Ring Oscillators

As processor clock frequencies become faster, architecture-level design is becoming increasingly limited by factors such as on-chip variation. Parameter variation occurs in integrated circuits as the result of a variety of manufacturing and physical factors. In this paper, we examine the degree to which there is parameter variation on an FPGA. Data were gathered from a combinatorial logic device instantiated on the FPGA. We analyze these data with respect to variance, and provide a confidence interval for the variance and standard deviation.

Abstract Totally Distributed Key Management for Dynamic Groups in MANETs

Most existing solutions to group security in Mobile Ad Hoc Networks (MANETs) rely on a multicast Core Based Tree (CBT) for key distribution. Such solutions, although suitable for systems with low mobility and static characteristics, are highly unsuitable for dynamic and sparse groups with changing neighborhoods. Also, tree based solutions are prone to a man-in-the-middle attack. This might lead to network partitioning with the attacker controlling one or more sections of the network. Another issue with tree based schemes is that a group controller is required to control the key generation process. In this paper, we propose an entirely decentralized key generation mechanism. Using our approach, keys can be established between group members with absolutely no prior communication, as long as the group members are known. The solution relies on threshold cryptography and introduces a novel concept of Node-Group-Key (NGK) mapping. Although our primary focus has been on group communication, our scheme can be easily extended to peer-to-peer communication, establishment of a distributed certification authority etc. We have provided an extensive analytical model for the computations involved, the communication costs and have also provided a ‘lie ’ detection and prevention mechanism. Simulation results show appreciable performance improvement and enhanced robustness. I. INRODUCTION The last few years have witnessed increased research in the field of group security in ad hoc networks. A group ca

UNCORRECTED PROOF

PP: 1-11 (col.fig.: nil