3148116
Modeling of wave behavior of substrate noise coupling for mixed-signal IC design
A new full-wave method is introduced for substrate noise analysis and simulation. The method is based on solution of the wave equation for the magnetic potential and can be implemented using standard circuit simulators. We compare the new method with the standard quasi-static method for typical substrate profiles and investigate the limits of validity of the quasi-static method.
5344006
Min/max on-chip inductance models and delay metrics
This paper proposes an analytical inductance extraction model for characterizing min/max values of typical on-chip global intercon-nect structures, and a corresponding delay metric that can be used to provide RLC delay prediction from physical geometries. The model extraction and analysis is efficient enough to be used within optimization and physical design exploration loops. The analytical min/max inductance approximations also provide insight into the effects caused by inductances.
9215156
Energy management using buffer memory for streaming data
This work presents a new approach for energy management by inserting data buffers. The buffers are managed using the concept of inventory control by treating energy as cost and computation as production. The data stored in the buffers are considered as merchandise. Our method provides a mathematical framework to develop general strategies managing the energy consumption in computers. The approach can solve a wide range of problems. For example, it can calculate the needed buffer sizes to achieve optimal energy savings. It can derive the conditions when a standby state saves energy. The method also shows the effect of load balancing on energy conservation and can handle the variations of data rates. We use sensor networks as case studies and demonstrate more than 20% energy savings.
14287933
Statistically optimal dynamic power management for streaming data
This paper presents a method that uses data buffers to create long periods of idleness to exploit power management. This method considers the power consumed by the buffers and assigns an energy penalty for buffer underflow. Our approach provides analytic formulas for calculating the optimal buffer sizes without subjective or heuristic decisions. We simulate four different hardware configurations with MPEG-1, MPEG-2, and MPEG-4 formats as a case study. Our results indicate that the optimal buffer size varies significantly for different data formats on different hardware. Simulation results indicate that 16 MB buffers are sufficient for MPEG-1, MPEG-2, and MPEG-4 video streams from a microdrive or a network card, but transfers from an IDE disk require buffer sizes ranging from 16 MB to 176 MB, depending on each video's statistical properties.
1334946
Program counter based techniques for dynamic power management
Reducing energy consumption has become one of the major challenges in designing future computing systems. We propose a novel idea of using program counters to predict I/O activities in the operating system. We present a complete design of program-counter access predictor (PCAP) that dynamically learns the access patterns of applications and predicts when an I/O device can be shut down to save energy. PCAP uses path-based correlation to observe a particular sequence of program counters leading to each idle period, and predicts future occurrences of that idle period. PCAP differs from previously proposed shutdown predictors in its ability to: (1) correlate I/O operations to particular behavior of the applications and users, (2) carry prediction information across multiple executions of the applications, and (3) attain better energy savings while incurring low mispredictions.
18145477
Wyner-Ziv Video Coding Based on Set Partitioning in Hierarchical Tree
In this paper, we propose a Wyner-Ziv video coding scheme based on set-partitioning in hierarchical trees (SPIHT) which can utilizing not only the spatial and temporal correlations but also the high-order statistical correlations. Wyner-Ziv theory on source coding with side information is employed as the basic coding principle, which makes the independent encoding and joint decoding become possible. In the proposed scheme, wavelet transform is first used to de-correlate the spatial dependency of a Wyner-Ziv frame. Then the quantized transform coefficients are organized by using magnitude with a set partitioning sorting algorithm. The ordered bit planes are coded using the Wyner-Ziv coding based on turbo codes. At the decoder, side information generated by motion compensated interpolation is used to conditionally decode the Wyner-Ziv frame. Since the high order statistical correlation is used, the proposed algorithm owns advantages over the traditional pixel-domain and transform-domain Wyner-ziv video coding schemes.
2412225
Dynamic Voltage Scaling for Multitasking Real-Time Systems With Uncertain Execution Time
Dynamic voltage and frequency scaling can save energy for real-time systems. Frequencies are generally assumed proportional to voltages. Previous studies consider the probabilistic distributions of tasks' execution time to assist dynamic voltage scaling in task scheduling. These studies use probability information for intratask voltage scheduling but do not sufficiently explore the opportunities for intertask scheduling to save more energy. This paper presents a new approach to combine intra- and intertask voltage scheduling for better energy savings in hard real-time systems with uncertain task execution time. Our approach takes three steps: 1) We calculate statistically the optimal voltage schedules for multiple concurrent tasks, using earliest deadline first scheduling for an ideal processor that can change the frequency continuously; 2) we then adapt the solution to a processor with a limited range of discrete frequencies, using a polynomial-time heuristic algorithm; and 3) finally, we improve our solution, considering the time and energy overheads of frequency switching for schedulability and energy reduction. Our simulation shows that the new approach can save more energy than existing solutions while meeting hard deadlines.