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.
10010061
Energy-efficient skewed static logic design with dual Vt
In this paper, we describe skewed static logic (S/sup 2/L) with topology-dependent dual Vt which exhibits energy-efficient operation. S/sup 2/L consumes less dynamic and static power compared to Monotonic Static (MS) CMOS. Speed degradation of S/sup 2/L can be offset by the accelerator. We have designed NAND-NOR gate chains using 0.18 /spl mu/m CMOS technology and verified that S/sup 2/L reduces energy/spl times/delay over MS CMOS by 27-50%. Synthesis algorithm for S/sup 2/L developed and the experimental results show S/sup 2/L consumes 23% less power than MS CMOS with minor increase in delay.
5129503
Detailed layer assignment for MCM routing
A new routing environment model, called the k-MCM model, is developed to take into account the unique features of a multilayer MCM, such as the availability of “segmented vias” , and the presence of two “active” or terminal-bearing layers. A detailed layer assignment problem is formulated on the k-MCM model. A fast heuristic algorithm for the layer assignment problem is proposed. and experimental results on twelve test examples with net counts up to 842 are presented.
16084555
2.4GHz ZigBee radio architecture with fast frequency offset cancellation loop
This paper describes a radio architecture with fast analog frequency offset cancellation loop which is based on a SigmaDelta fractional-N frequency synthesizer and a frequency offset detector. The offset detector is composed of a frequency/phase detector (PFD) and a new non-uniform resolution time-to-digital converter (TDC). By adopting the weighted delay-length for the TDC, only 60-DFFs are used to generate digitized timing difference of 250ns with a minimum resolution of 1ns. For the 2.4GHz ZigBee transceiver with 4MHz IF, designed for 0.18mum CMOS process, the frequency offset cancellation time takes about 30mus under the PLL loop-bandwidth of 100 kHz
1671645
Domino logic synthesis minimizing crosstalk
Based on the new concept of crosstalk immunity set (CIS), procedures to minimize capacitive cross-coupling effects are developed for domino logic circuit. The nets in a crosstalk immunity set are free from crosstalk effects for any combination of input vectors. New algorithms for CIS identification and minimization are proposed to maximize the chance of crosstalk minimization in routing step. Our routing algorithm augmented with CIS information searches for optimal solution to minimize maximum crosstalk the circuit would experience. Experimental results show that the reduction of maximum crosstalk is up to 30% with CIS-augmented routing.
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>>
30593608
Skyeye: An Instruction Simulator with Energy Awareness
This paper presents a novel strategy aimed at modeling the instruction energy consumption of ARM microprocessors with dynamic voltage scaling (DVS) support. A novel energy estimation algorithm is designed, which can record the function calls, and generate a detailed energy profile for each function in a specific program. Some of the optimization policies for implementation are also discussed. These optimization policies reduce the workload of the energy estimators for the individual SOC systems. The prototype system, SKYEYE, can automatically detect the voltage/frequency variation activated by DVS system, and adjust the energy estimation model accordingly. The experiment results further prove the effectiveness of the algorithm.
40596005
Survey of image-based representations and compression techniques
We survey the techniques for image-based rendering (IBR) and for compressing image-based representations. Unlike traditional three-dimensional (3-D) computer graphics, in which 3-D geometry of the scene is known, IBR techniques render novel views directly from input images. IBR techniques can be classified into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories and their representative techniques. IBR techniques demonstrate a surprising diverse range in their extent of use of images and geometry in representing 3-D scenes. We explore the issues in trading off the use of images and geometry by revisiting plenoptic-sampling analysis and the notions of view dependency and geometric proxies. Finally, we highlight compression techniques specifically designed for image-based representations. Such compression techniques are important in making IBR techniques practical.
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.
2304584
Directional histogram model for three-dimensional shape similarity
In this paper, we propose a novel shape representation we call directional histogram model (DHM). It captures the shape variation of an object and is invariant to scaling and rigid transforms. The DHM is computed by first extracting a directional distribution of thickness histogram signatures, which are translation invariant. We show how the extraction of the thickness histogram distribution can be accelerated using conventional graphics hardware. Orientation invariance is achieved by computing the spherical harmonic transform of this distribution. Extensive experiments show that the DHM is capable of high discrimination power and is robust to noise.
16869035
An approach to virtual allocation in storage systems
This article presents virtual allocation, a scheme for flexible storage allocation. Virtual allocation separates storage allocation from the file system. It employs an allocate-on-write strategy which lets applications fit into the actual usage of storage space, without regard to the configured file system size. This improves flexibility by allowing storage space to be shared across different file systems. This article presents the design of virtual allocation and its evaluation through benchmarks. To illustrate our approach, we implemented a prototype system on PCs running Linux. We present the results from the prototype implementation and its evaluation.