4540340
Transistor sizing for reliable domino logic design in dual threshold voltage technologies
Dynamic logic is much susceptible to noise specially in ul tra deep submicron technology The keeper transistor has to be carefully sized to maintain noise margin without much speed penalty In this paper we analyze the keeper tran sistor sizing with respect to the size of NMOS transistors in the evaluation tree Based on the analytical results we propose a keeper transistor sizing method HSPICE simula tion results show that the proposed keeper transistor sizing method can be broadly applied to all domino logic gates
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.
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>>
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>>
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.
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%.
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.
17348246
Lighting interpolation by shadow morphing using intrinsic lumigraphs
Densely-sampled image representations such as the light field or lumigraph have been effective in enabling photorealistic image synthesis. Unfortunately, lighting interpolation with such representations has not been shown to be possible without the use of accurate 3D geometry and surface reflectance properties. In this paper we propose an approach to image-based lighting interpolation that is based on estimates of geometry and shading from relatively few images. We decompose captured light fields at different lighting conditions into intrinsic images (reflectance and illumination images), and estimate view-dependent scene geometries using multi-view stereo. We call the resulting representation an intrinsic lumigraph. In the same way that the lumigraph uses geometry to permit more accurate view interpolation, the intrinsic lumigraph uses both geometry and intrinsic images to allow high-quality interpolation at different views and lighting conditions. Joint use of geometry and intrinsic images is effective in the computation of shadow masks for shadow prediction at new lighting conditions. We illustrate our approach with images of real scenes.
16190492
Noise Estimation from a Single Image
In order to work well, many computer vision algorithms require that their parameters be adjusted according to the image noise level, making it an important quantity to estimate. We show how to estimate an upper bound on the noise level from a single image based on a piecewise smooth image prior model and measured CCD camera response functions. We also learn the space of noise level functions how noise level changes with respect to brightness and use Bayesian MAP inference to infer the noise level function from a single image. We illustrate the utility of this noise estimation for two algorithms: edge detection and featurepreserving smoothing through bilateral filtering. For a variety of different noise levels, we obtain good results for both these algorithms with no user-specified inputs.
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.
18462898
Rendering with Non-uniform Approximate Concentric Mosaics
In this paper, we explore the more practical aspects of building and rendering concentric mosaics. First, we use images captured with only approximately circular camera trajectories. The image sequence capture can be achieved by holding a camcorder in position and rotating the body all around. In addition, we investigate the use of variable input sampling and fidelity of scene geometry based on the level of interest (and hence quality of view synthesized) on the objects in the scene. We achieve the tolerance for minor perturbations about the exact circular camera path and variable input sampling by using and analyzing a variant of the Hough space of all captured rays. Examples using real scenes are shown to validate our approach.