Guarded Evaluation: An Algorithm for Dynamic Power Reduction in FPGAs

Guarded evaluation is a power reduction technique that involves identifying sub-circuits (within a larger circuit) whose inputs can be held constant (guarded) at specific times during circuit operation, thereby reducing switching activity and lowering dynamic power. The concept is rooted in the property that under certain conditions, some signals within digital designs are not "observable" at design outputs, making the circuitry that generates such signals a candidate for guarding. Guarded evaluation has been demonstrated successfully for custom ASICs; in this work, we apply the technique to FPGAs. In ASICs, guarded evaluation entails adding additional hardware to the design, increasing silicon area and cost. Here, we apply the technique in a way that imposes minimal area overhead by leveraging existing unused circuitry within the FPGA. The LUT functionality is modified to incorporate the guards and reduce toggle rates. The primary challenge in guarded evaluation is in determining the specific conditions under which a sub-circuit's inputs can be held constant without impacting the larger circuit's functional correctness. We propose a simple solution to this problem based on discovering gating inputs using "non-inverting paths" and trimming inputs using "partial non-inverting paths" in the circuit's AND-Inverter graph representation. Experimental results show that guarded evaluation can reduce switching activity by as much as 32% for FPGAs with 6-LUT architectures and 25% for 4-LUT architectures, on average, and can reduce power consumption in the FPGA interconnect by 29% for 6-LUTs and 27% for 4-LUTs. A clustered architecture with four LUTs to a cluster and ten LUTs to a cluster produced the best power reduction results. We implement guarded evaluation at various stages of the FPGA CAD flow and analyze the reductions. We implement the algorithm as post technology mapping, post packing and post placement optimizations. Guarded Evaluation as a post technology mapping algorithm inserted the most number of guards and hence achieved the highest activity and interconnect reduction. However, guarding signals come with a cost of increased fanout and stress on routing resources. Packing and placement provides the algorithm with additional information of the circuit which is leveraged to insert high quality guards with minimal impact on routing. Experimental results show that post-packing and post-placement methods have comparable reductions to post-mapping with considerably lesser impact on the critical path delay and routability of the circuit

Monetary policy report to the Congress, March 1, 2011

Monetary policy - United States ; Economic conditions - United States

The IPS fidelity scale as a guideline to implement Supported Employment

info:eu-repo/semantics/publishe

Regulating Ex Post: How Law Can Address the Inevitability of Financial Failure

Unlike many other areas of regulation, financial regulation operates in the context of a complex interdependent system. The interconnections among firms, markets, and legal rules have implications for financial regulatory policy, especially the choice between ex ante regulation aimed at preventing financial failure and ex post regulation aimed at responding to that failure. Regulatory theory has paid relatively little attention to this distinction. Were regulation to consist solely of duty-imposing norms, such neglect might be defensible. In the context of a system, however, regulation can also take the form of interventions aimed at mitigating the potentially systemic consequences of a financial failure. We show that this dual role of financial regulation implies that ex ante regulation and ex post regulation should be balanced in setting financial regulatory policy, and we offer guidelines for achieving that balance

Congressional Oversight Panel March oversight report : the final report of the Congressional Oversight Panel.

"March 16, 2011."Shipping list no.: 2011-0268-P.Includes bibliographical references.Mode of access: Internet

The first global financial crisis of the 21st century: Part II, June-December, 2008

This book is a selection of VoxEU.org columns that deal with the ongoing global financial crisis. VoxEU.org is a portal for research-based policy analysis and commentary written by leading economists. It was launched in June 2007 with the aim of enriching the economic policy debate by making it easier for serious researchers to contribute and to make their contributions more accessible to the public

A Citizen\u27s Guide to the 2009 Financial Report of the U.S. Government

Oversight report containing a section on the Automotive Industry Financing Program (AIFP), which includes the Bridge Loans to GM and Chrysler