End-to-End Industrial Study of Retiming

Sequential circuits are combinational circuits that are separated by registers. Retiming is considered as the most promising technique for optimizing sequential circuits, that involves moving the edge-triggered registers across the combinational logic without changing the functionality. Despite significant efforts spent on sequential optimization since 1980's, there are few works discussed its performance in an end to-end design flow. The retiming algorithms were mostly evaluated at the logic level. However, it turns out that the retiming results at logic level could be significantly different than evaluating the physical level.This paper provides the findings of how retiming algorithms perform in an end-to-end industrial design flow, with seven industry designs taken from a recent 14nm microprocessor. Experiments are conducted with several complete industrial design flows. The evaluations are made at the end of the physical design flow. The experimental results show that the performance (design quality) of the retiming algorithms vary on the designs. Based these experimental results, we discover a feature that describes the retiming potentials of sequential designs. This model successfully forecast whether the given industrial designs could be significantly improved by retiming in an end-to-end design flow, regarding timing, area, and power

Mix & Latch: An Optimization Flow for High-Performance Designs with Single-Clock Mixed-Polarity Latches and Flip-Flops

Flip-flops are the most used sequential elements in synchronous circuits, but designs based on latches can operate at higher frequencies and occupy less area. Techniques to increase the maximum operating frequency of flip-flop based designs, such as time-borrowing, rely on tight hold constraints that are difficult to satisfy using traditional back-end optimization techniques. We propose Mix & Latch , a methodology to increase the operating frequency of synchronous digital circuits using a single clock tree and a mixed distribution of positive- and negative-edge-triggered flops, and positive- and negative-level-sensitive latches. An efficient mathematical model is proposed to optimize the type and location of the sequential elements of the circuit. We ensure that the initial registers are not moved from their initial location, although they may change type, thus allowing the use of equivalence checking and static timing analysis to verify formally the correctness of the transformation. The technique is validated using a 28nm CMOS FDSOI technology, obtaining 1.33X post-layout average operating frequency improvement on a broad set of benchmarks over a standard commercial design flow. Additionally, the circuit area was also reduced by more than 1.19X on average for the same benchmarks, although the overall area reduction is not a goal of the optimization algorithm. To the best of our knowledge, this is the first work that proposes combining mixed-polarity flip-flops and latches to improve the circuit performance

Three Essays on Investment.

This dissertation studies the supply and demand of capital goods, and the effects of investment tax incentives. Chapter II examines the effects of investment tax incentives. The evidence indicates that subsidies increase capital goods purchases more than domestic production so investment subsidies also stimulate foreign capital goods producers. At capital producing firms, measures of economic increase substantially following an investment tax subsidy. The data is used to estimate the key parameters of a multi-sector, open-economy DSGE model with capita and labor adjustment costs. In the estimated model, investment tax incentives are strong enough to cause noticeable changes in aggregate economic activity. The import supply elasticity is considerable, allowing investment to rise even in the short-run in response to investment subsidies. Chapter III develops an equilibrium model of investment with retiming costs at the micro-level. In the benchmark case in which investment retiming costs are zero, this model and standard fixed-costs models generate virtually identical aggregate predictions. If the timing adjustment costs are positive, then capital goods prices may exhibit predictable changes over time. Simulated impulse responses in the quantitative model are then used to analyze the effects of retiming costs on the effectiveness of investment of tax subsidies, the economy’s reaction to transitory investment supply shocks, and an out-of-steady state distribution of capital vintages. In the presence of retiming costs, temporary subsidies are less effective and cause a fall in investment after they expire. Additionally, investment supply shocks have an attenuated effect of investment relative to the benchmark case. Chapter IV studies the supply of capital goods. The data indicate that for equipment, the elasticity of investment supply is considerable, while for structures the elasticity of investment supply is close to unity. After calibrating the elasticity of investment supply, investment supply shocks are recovered for each capital type. Using a mix of reduced-form and structural time-series techniques, the structural parameters of the permanent and transitory components for each series are estimated from the data. The analysis suggests that permanent shocks are more prominent than transitory shocks and that the permanent and transitory components are strongly negatively correlated.PhDEconomicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/116656/1/ammocanu_1.pd

Business improvement districts in urban freight sustainability initiatives: a case study approach

The paper extends research into the importance of freight transport partnerships by considering the role of Business Improvement Districts (BIDs) in supporting sustainable urban freight initiatives. A review of the freight transport-related work that has been carried out in BIDs in central London is included. A detailed case study of a freight project in the Baker Street Quarter (BSQ) Partnership provides insight into work carried out in the multi-tenanted office and hotel sectors. The findings of this research in terms of freight transport and logistics activity patterns at the businesses studied together with the potential freight transport solutions identified are discussed

Evaluating Architectural, Redundancy, and Implementation Strategies for Radiation Hardening of FinFET Integrated Circuits

In this article, authors explore radiation hardening techniques through the design of a test chip implemented in 16-nm FinFET technology, along with architectural and redundancy design space exploration of its modules. Nine variants of matrix multiplication were taped out and irradiated with neutrons. The results obtained from the neutron campaign revealed that the radiation-hardened variants present superior resiliency when either local or global triple modular redundancy (TMR) schemes are employed. Furthermore, simulation-based fault injection was utilized to validate the measurements and to explore the effects of different implementation strategies on failure rates. We further show that the interplay between these different implementation strategies is not trivial to capture and that synthesis optimizations can effectively break assumptions about the effectiveness of redundancy schemes

Future broadband access network challenges

Copyright @ 2010 IEEEThe optical and wireless communication systems convergence will activate the potential capacity of photonic technology for providing the expected growth in interactive video, voice communication and data traffic services that are cost effective and a green communication service. The last decade growth of the broadband internet projects the number of active users will grow to over 2 billion globally by the end of 2014. Enabling the abandoned capacity of photonic signal processing is the promising solution for seamless transportation of the future consumer traffic demand. In this paper, the future traffic growth of the internet, wireless worldwide subscribers, and the end-users during the last and next decades is investigated. The challenges of the traditional access networks and Radio over Fiber solution are presented