5194747
ESD design rule checker
Electrostatic discharge (ESD) protection circuitry is essential for every I/O cell design and has its own set of design rules. These design rules are not only complex but also beyond the scope of commercial DRC tools. In this paper, we present the framework of our ESD design rule checker, and address some of the open issues in the ESD design rule checker presented by Sinha et al. (1998).
13548202
Noise constrained power optimization for dual V/sub T/ domino logic
In dual threshold voltage techniques, significant subthreshold leakage current is one of the most important design problems. When dual threshold voltage is applied to the domino logic, noise immunity has to be carefully considered because the significant subthreshold current makes dynamic nodes much more susceptible to noise. In this paper, an analytical model for proper keeper transistor sizing to meet noise constraint is presented. Based on the same noise constraint, we propose dual threshold voltage domino logic technique to save power consumption.
40491047
Domino logic synthesis based on implication graph
In this paper, we present a new approach to the problem of inverter elimination in domino logic synthesis. A small piece of static CMOS logic is introduced to the circuit to avoid significant area penalty resulting from duplication. To maximize the domino logic part and to minimize the static CMOS logic part, a generalized automatic test pattern generation (ATPG)-based logic transformation is proposed to eliminate or relocate a target inverter. Based on the new concept of dominating set of mandatory assignment (DSMA) and the corresponding implication graph, we propose algorithms to identify a minimum candidate set for a target inverter. Experimental results show that logic transformation based on the implication graph can reduce transistor counts by 25% on average, while the delay increases less than 3%.
14376041
Feasible region approximation using convex polytopes
A new technique for polytope approximation of the feasible region for a design is presented. This method is computationally less expensive than the simplicial approximation method. Results on several circuits are presented. It is shown that the quality of the polytope approximation is substantially better than an ellipsoidal approximation.<<ETX>>
13489029
An integrated approach to realistic worst-case design optimization of MOS analog circuits
The authors present a new integrated approach for the optimization of MOS analog circuit performance by using realistic worst-case device parameter files, each corresponding to a performance measure. Nonlinear response surfaces are constructed for the performance measures of interest, and the worst-case device parameter files are identified by solving a set of suitably cast nonlinear programming problems. The worst-case files are shown to depend on the values of the designable parameters. An efficient method of incorporating this dependence during worst-case design optimization has been developed. This method enables the design of circuits with optimal performance and high parametric yields. Some illustrative analog circuit examples are given to demonstrate the application of the worst-case design optimization procedure.<<ETX>>
44275614
Cell-level placement for improving substrate thermal distribution
The dramatic increase of power consumption in very large scale integration circuits has led to high operating temperature and large thermal gradient, thereby resulting in serious timing and reliability concerns. Temperature-tracking is thus becoming of paramount importance in modern electronic design automation (EDA) tools. In this paper we present two thermal placement tools for standard cell and macro cell design styles respectively. They are aimed at reducing hot spots in a design without compromising traditional design metrics such as area and wire length. We developed a compact substrate thermal model that can be used by the placer to calculate the temperature profile of a placement efficiently, or to convert the user-specified temperature constraint into the corresponding power distribution constraint as an alternative placement objective. As a result, our method is much more efficient than directly employing temperature profile simulation during the placement process. The simulation results show noticeable improvement of thermal distribution over the traditional placement algorithm, with little impact on area and wire length of the final layout.
5958118
Delayed stability and performance of distributed congestion control
Recent research efforts to design better Internet transport protocols combined with scalable Active Queue Management (AQM) have led to significant advances in congestion control. One of the hottest topics in this area is the design of discrete congestion control algorithms that are asymptotically stable under heterogeneous feedback delay and whose control equations do not explicitly depend on the RTTs of end-flows. In this paper, we show that max-min fair congestion control methods with a stable symmetric Jacobian remain stable under arbitrary feedback delay (including heterogeneous directional delays) and that the stability condition of such methods does not involve any of the delays. To demonstrate the practicality of the obtained result, we change the original controller in Kelly's work [14] to become robust under random feedback delay and fixed constants of the control equation. We call the resulting framework Max-min Kelly Control (MKC) and show that it offers smooth sending rate, exponential convergence to efficiency, and fast convergence to fairness, all of which make it appealing for future high-speed networks.
7236201
Catadioptric self-calibration
We have assembled a standalone, movable system that can capture long sequences of omnidirectional images (up to 1,500 images at 6.7 Hz and a resolution of 1140/spl times/090). The goal of this system is to reconstruct complex large environments, such as an entire floor of a building, from the captured images only. In this paper, we address the important issue of how to calibrate such a system. Our method uses images of the environment to calibrate the camera, without the use of any special calibration pattern, knowledge of camera motion, or knowledge of scene geometry. It uses the consistency of pairwise tracked point features across a sequence based on the characteristics of catadioptric imaging. We also show how the projection equation for this catadioptric camera can be formulated to be equivalent to that of a typical rectilinear perspective camera with just a simple transformation.
16309802
Virtual Navigation of Complex Scenes using Clusters of Cylindrical Panoramic Images
The traditional approach of generating novel virtual views of an object or a scene is to render the appropriate 3-D model. Higher realism can be achieved by texture-mapping object surfaces or simulating surface reflectance properties. The alternative is to render directly from the original images; this approach, which is based on pixel interpolation or reprojection, is called image-based rendering. In this technical report, we describe a technique that enables virtual navigation within a complex environment using an image-based rendering technique. In particular, we make use of clusters of cylindrical panoramic images. Each cluster of panoramic images allows the user to smoothly navigate within a particular area, say within a single room. Having a collection of such interconnected clusters would enable the user to seamlessly navigate within a complex environment, such as an entire floor of a building, with each cluster representing a room. To achieve this goal, we examine a few techniques for image-based rendering using a cluster of cylindrical panoramic images to synthesize views from virtual viewpoints. We also describe our method for enabling smooth transition between clusters. 1Computer Science Dept., Duke University, Durham, NC 27708 c Digital Equipment Corporation, 1997 This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of the Cambridge Research Laboratory of Digital Equipment Corporation in Cambridge, Massachusetts; an acknowledgment of the authors and individual contributors to the work; and all applicable portions of the copyright notice. Copying, reproducing, or republishing for any other purpose shall require a license with payment of fee to the Cambridge Research Laboratory. All rights reserved. CRL Technical reports are available on the CRL’s web page at http://www.crl.research.digital.com. Digital Equipment Corporation Cambridge Research Laboratory One Kendall Square, Building 700 Cambridge, Massachusetts 02139
8347342
Keyword-based document clustering
Document clustering is an aggregation of related documents to a cluster based on the similarity evaluation task between documents and the representatives of clusters. Terms and their discriminating features of terms are the clue to the clustering and the discriminating features are based on the term and document frequencies. Feature selection method on the basis of frequency statistics has a limitation to the enhancement of the clustering algorithm because it does not consider the contents of the cluster objects. In this paper, we adopt a content-based analytic approach to refine the similarity computation and propose a keyword-based clustering algorithm. Experimental results show that content-based keyword weighting outperforms frequency-based weighting method.
61448634
Single-Image Vignetting Correction
In this paper, we propose a method for determining the vignetting function given only a single image. Our method is designed to handle both textured and untextured regions in order to maximize the use of available information. To extract vignetting information from an image, we present adaptations of segmentation techniques that locate image regions with reliable data for vignetting estimation. Within each image region, our method capitalizes on frequency characteristics and physical properties of vignetting to distinguish it from other sources of intensity variation. The vignetting data acquired from regions are weighted according to a presented reliability measure to promote robustness in estimation. Comprehensive experiments demonstrate the effectiveness of this technique on a broad range of images.