7167027
Power and thermal effects of SRAM vs. latch-mux design styles and clock gating choices
This paper studies the impact on energy efficiency and thermal behavior of design style and clock-gating style in queue and array structures. These structures are major sources of power dissipation, and both design styles and various clock gating schemes can be found in modern, high-performance processors. Although some work in the circuits domain has explored these issues from a power perspective, thermal treatments are less common, and we are not aware of any work in the architecture domain. We study both SRAM and latch and multiplexer ("latch-mux") designs and their associated clock-gating options. Using circuit-level simulations of both design styles, we derive power-dissipation ratios which are then used in cycle-level power/performance/thermal simulations. We find that even though the "unconstrained" power of SRAM designs is always better than latch-mux designs, latch-mux designs dissipate less power in practice when a structure's average occupancy is low but access rate is high, especially when "stall gating" is used to minimize switching power. We also find that latch-mux designs with stall gating are especially promising from a thermal perspective, because they exhibit lower power density than SRAM designs. Overall, when combined with implementation and verification challenges for SRAMs, latch-mux designs with stall gating appear especially promising for designs with thermal constraints. This paper also shows the importance of considering the interaction between architectural and circuit design choices when performing early-stage design exploration.
2533092
State-preserving vs. non-state-preserving leakage control in caches
This paper compares the effectiveness of state-preserving and non-state-preserving techniques for leakage control in caches by comparing drowsy cache and gated-V/sub ss/ for data caches using 70nm technology parameters. To perform the comparison, we introduce "HotLeakage", a new architectural model for subthreshold and gate leakage that explicitly models the effects of temperature, voltage, and parameter variations, and has the ability to recalculate leakage currents dynamically as temperature and voltage change at runtime due to operating conditions, DVS techniques, etc. By comparing drowsy-cache and gated-V/sub ss/ at different L2 latencies and different gate oxide thickness values, we are able to identify a range of operating parameters at which gated-V/sub ss/ is more energy efficient than drowsy-cache, even though gated-V/sub ss/ does not preserve data in cache lines that have been deactivated. We are also able to show potential further benefits of gated-V/sub ss/ if an effective dynamic adaptation technique can be found. These results debunk a fairly widespread belief that state-preserving techniques are inherently superior to non-state-preserving techniques.
1371524
Continuous-time digital signal processors
In this paper, we discuss how asynchronous design techniques can be used in the implementation of continuous-time signal processors. Such processors are presented by signals developed by continuous-time analog-to-digital converters which involve no sampling, and thus do not exhibit aliasing; in addition, the resulting in-band quantization error is lower than in conventional techniques. Several design considerations are given, and preliminary experimental results are presented.
18839021
Adaptive-Subcube Fault Tolerant Routing in Dual-Cube with Very Large Number of Faulty Nodes
The dual-cube is a newly proposed interconnection network for linking a large amount of nodes with low node degree. It uses low-dimensional hypercubes as building blocks and keeps the main desired properties of the hypercubes. In this paper, we give an efficient algorithm for fault tolerant routing in dual-cube networks with a large number of faulty nodes. Our algorithm uses the adaptive-subcube technique to select a suitable dimension to route a node. This technique not only increases the routing speed but also shortens the path and improves the successful routing rate. The experimental results show that, with high percentages of node failures, the algorithm can build routing paths with a very high probability. Our simulation results show that when a dual-cube with 32,768 nodes contains up to 20 percent faulty nodes, the success rate of constructing a faultfree path between any two nonfaulty nodes is 99.5 percent with a 4-subcube.
16081168
Sample dependence correction for order selection in fMRI analysis
Multivariate analysis methods such as independent component analysis (ICA) have been applied to the analysis of functional magnetic resonance imaging (fMRI) data to study the brain function. The selection of the proper number of signals of interest is an important step in the analysis to reduce the risk of over/underfilling. The inherent sample dependence in the spatial or temporal dimension of the fMRI data violates the assumption of independent and identically distributed (i.i.d.) samples and limits the usefulness of the practical formulations of information-theoretic order selection criteria. We propose a novel method using an entropy rate matching principle to mitigate the effects of such sample dependence in order selection. We perform order selection experiments on the simulated fMRI data and show that the incorporation of the proposed method significantly improves the accuracy of the order selection by different criteria. We also use the proposed method to estimate the number of latent sources in fMRI data acquired from multiple subjects performing a visuomotor paradigm. We show that the proposed method improves the order selection by alleviating the over-estimation due to the intrinsic smoothness and the effect of smooth preprocessing on the fMRI data
14632183
Collection of network information in active networks
Collection of information about the state of the network is very important for applications both in active networks and in traditional passive networks. However, the existing methods for the collection and prediction of network state cannot meet the needs of complex and intelligent applications. Active networks provide an environment that supports the injection and execution of application-specified codes in the network nodes, and consequently suggest possibilities for the solving of such a problem. In this article we present a new method for the collection of network state information by describing how active network techniques can be used to collect this information more freely and in a user-specific way. We give also an implementation of this approach to collect network resource information and evaluate it by measurements. By using this method, users can specify both the content and the format of the network resource information that they want to acquire as well as nodes at which they want to gather these information.
40993420
Heuristic Walkthroughs Evaluation of Pen-Based Chinese Word Edit System (PCWES) Usability
An evaluation experiment was conducted to compare four interface styles: Hanwang Fixed Window, Translucent Mobile Single Window, Translucent Mobile Double Window, and No Window. Subjects tested the four styles on a pen_based word edit system in free-form mode. The result shows that traditional interface style of the Hanwang Fix Window didn't satisfy the requirement of the nature interaction of the end user. And the TMDW mode are very suitable for user to perform the word processing task, in terms of the task performing time and mean accuracy rate. And the NW is the most nature and promising style, in terms of the subjective preference and the error rate of the performing time and accuracy rate of the experimental data. The experiment also shows that the moving window would influent the accuracy rate of the recognition. This experiment confirmed that a proper employment of interface style could improve the interactive efficiency of word editing systems. Also we give out some useful interface hints to improve the performance of the interface. Our tests for the first time give statistical support to the view that free pen_based interface is meaningful in the nature pen and gesture input of the word edit system.