14664253
A Bit-Width Optimization Methodology for Polynomial-Based Function Evaluation
We present an automated bit-width optimization methodology for polynomial-based hardware function evaluation. Due to the analytical nature of the approach, overflow protection and precision accurate to one unit in the last place (ulp) can be guaranteed. A range analysis technique based on computing the root of the derivative of a signal is utilized to determine the minimal number of integer bits. Fractional bit requirements are established using an analytical error expression derived from the functions that occur along the data path. Global fractional bit optimization across multiple computation stages is performed using simulated annealing and circuit area estimation functions
2458216
Non-uniform Segmentation for Hardware Function Evaluation
This paper presents a method for evaluating functions in hardware based on polynomial approximation with non-uniform segments. The novel use of non-uniform segments enables us to approximate non-linear regions of a function particularly well. The appropriate segment address for a given function can be rapidly calculated in run time by a simple combinational circuit. Scaling factors are used to deal with large polynomial coefficients and to trade precision with range. Our function evaluator is based on first-order polynomials, and is suitable for applications requiring high performance with small area, at the expense of accuracy. The proposed method is illustrated using two functions, \(\sqrt{-\ln(x)}\) and cos(2 πx), which have been used in Gaussian noise generation.
17000769
On crossing minimization problem
In this paper, we consider a problem related to global routing postoptimization: the crossing minimization problem (CMP). Given a global routing representation, the CMP is to minimize redundant crossings between every pair of nets. In particular, there are two kinds of CMP: constrained CMP (CCMP) and unconstrained CMP (UCMP). These problems have been studied previously where an O(m/sup 2/n) algorithm was proposed for CCMP, and where an (mn/sup 2/+/spl xi//sup 2/) algorithm was proposed for UCMP where m is the total number of modules, n is the number of nets, and /spl xi/ is the number of crossings defined by an initial global routing topology. We present a simpler and faster O(mn) algorithm for CCMP and an O[n(m+/spl xi/)] time algorithm for UCMP. Both algorithms improve over the time bounds of the previously proposed algorithms. The novel part of our algorithm is that it uses the plane embedding information of globally routed nets in the routing area to construct a graph-based framework and obtain a good junction terminal assignment that minimizes the number of crossings.
7800252
Imprecise data computation for high performance asynchronous processors
Instruction level parallelism(ILP) is strictly limited by various dependencies. In particular , data dependency is the major performance bottleneck of data intensive applications. To accelerate the execution of sequential code serialized due to data dependencies, this paper proposes an imprecise computation as a fast data computing technique for a high-performance asynchronous processor. To show the performance benefits of the suggested computing model, simulation results are presented. The imprecise computation can be used effectively in data intensive processing with a microprocessor, a Digital Signal Processor or a multimedia processor.
7421438
A reliable position estimation method of the service robot by map matching
In this paper, a reliable position estimation method of the indoor service robot is proposed. The service robot PSR1 is a wheeled mobile manipulator which navigates in office buildings. Our localization method is a map-matching scheme using scanned range data, without using any artificial landmark. The proposed algorithm can provide solutions for both a global localization problem and a local position tracking. A probabilistic position estimation scheme is designed based on MCL (Monte Carlo localization). Two measure functions are developed for computing positional probabilities. The robot automatically decides whether it uses geometric pattern matching (i.e. walls, pillars) by Hough transform. The proposed scheme shows reliable performance in both polygonal environments and non-polygonal environments even there exist many obstacles. Experimental results demonstrate the validity and feasibility of the proposed localization algorithm for the service robot to navigate in an office building, using the natural environmental characteristics.
38005392
Towards Web-Based Computing
In a problem solving environment for geometric computing, a graphical user interface, or GUI, for visualization has become an essential component for geometric software development. In this paper we describe a visualization system, called GeoJAVA, which consists of a GUI and a geometric visualization library that enables the user or algorithm designer to (1) execute and visualize an existing algorithm in the library or (2) develop new code over the Internet. The library consists of geometric code written in C/C++. The GUI is written using the Java programming language. Taking advantage of the socket classes and system-independent application programming interfaces (API's) provided with the Java language, GeoJAVA offers a platform independent environment for distributed geometric computing that combines Java and C/C++. Users may remotely join a "channel" or discussion group in a location transparent manner to do collaborative research. The visualization of an algorithm, a C/C++ program located locally or remotely and controlled by a "floor manager", can be viewed by all the members in the channel through a visualization sheet called GeoJAVASheet. A chat box is also provided to enable dialogue among the members. Furthermore, this system not only allows visualization of pre-compiled geometric code, but also serves as a web-based programming environment where the user may submit a geometric code, compile it with the libraries provided by the system, and visualize it directly over the web sharing it with other users immediately.
17000976
A Faster One-Dimensional Topological Compaction Algorithm
We consider the problem of one-dimensional topological compaction with jog insertions. Combining both geometric and graph theoretic approaches we present a faster and simpler algorithm, improving over previous results. The compaction algorithm takes as input a sketch consisting of a set F of features and a set W of wires, and minimizes the horizontal width of the sketch while maintaining its routability. The algorithm consists of the following steps: constructing a horizontal constraint graph, computing all possible jog positions, computing the critical path, relocating the features and reconstructing a new sketch homotopic to the input sketch suitable for detailed routing. The algorithm runs in O(|F| · |W|) worst-case time and space, which is asymptotically optimal in the worst case. Experimental results are also presented.