Design of Asynchronous Circuits for High Soft Error Tolerance in Deep Submicron CMOS Circuits

As the devices are scaling down, the combinational logic will become susceptible to soft errors. The conventional soft error tolerant methods for soft errors on combinational logic do not provide enough high soft error tolerant capability with reasonably small performance penalty. This paper investigates the feasibility of designing quasi-delay insensitive (QDI) asynchronous circuits for high soft error tolerance. We analyze the behavior of null convention logic (NCL) circuits in the presence of particle strikes, and propose an asynchronous pipeline for soft-error correction and a novel technique to improve the robustness of threshold gates, which are basic components in NCL, against particle strikes by using Schmitt trigger circuit and resizing the feedback transistor. Experimental results show that the proposed threshold gates do not generate soft errors under the strike of a particle within a certain energy range if a proper transistor size is applied. The penalties, such as delay and power consumption, are also presented

Blind Multilinear Identification

We discuss a technique that allows blind recovery of signals or blind identification of mixtures in instances where such recovery or identification were previously thought to be impossible: (i) closely located or highly correlated sources in antenna array processing, (ii) highly correlated spreading codes in CDMA radio communication, (iii) nearly dependent spectra in fluorescent spectroscopy. This has important implications --- in the case of antenna array processing, it allows for joint localization and extraction of multiple sources from the measurement of a noisy mixture recorded on multiple sensors in an entirely deterministic manner. In the case of CDMA, it allows the possibility of having a number of users larger than the spreading gain. In the case of fluorescent spectroscopy, it allows for detection of nearly identical chemical constituents. The proposed technique involves the solution of a bounded coherence low-rank multilinear approximation problem. We show that bounded coherence allows us to establish existence and uniqueness of the recovered solution. We will provide some statistical motivation for the approximation problem and discuss greedy approximation bounds. To provide the theoretical underpinnings for this technique, we develop a corresponding theory of sparse separable decompositions of functions, including notions of rank and nuclear norm that specialize to the usual ones for matrices and operators but apply to also hypermatrices and tensors.Comment: 20 pages, to appear in IEEE Transactions on Information Theor

How to speedup fault-tolerant clock generation in VLSI systems-on-chip via pipelining

Fault-tolerant clocking schemes become inevitable when it comes to highly-reliable chip designs. Because of the additional hardware overhead, existing solutions are considerably slower than their non-reliable counterparts. In this paper, we demonstrate that pipelining is a viable approach to speed up the distributed fault-tolerant DARTS clock generation approach introduced in (Függer, Schmid, Fuchs, Kempf, EDCC'06), where a distributed Byzantine fault-tolerant tick generation algorithm has been used to replace the traditional quartz oscillator and highly balanced clock tree in VLSI Systems-on-Chip (SoCs). We provide a pipelined version of the original DARTS algorithm, termed pDARTS, together with a novel modeling and analysis framework for hardware-implemented asynchronous fault-tolerant distributed algorithms, which is employed for rigorously analyzing its correctness & performance. Our results, which have also been confirmed by the experimental evaluation of an FPGA prototype implementation, reveal that pipelining indeed allows to entirely remove the adverse effect of large interconnect delays on the achievable clock frequency, and demonstrate again that methods and results from distributed algorithms research can successfully be applied in the VLSI context

Artful Good Faith: An Essay on Law, Custom, and Intermediaries in Art Markets

This Essay explores relationships between custom and law in the United States in the context of markets for art objects. The Essay argues that these relationships are dynamic, not static, and that law can prompt evolution in customary practice well beyond the law\u27s formal requirements. Understanding these relationships in the context of art markets requires due attention to two components distinctive to art markets: the role of dealers and auction houses as transactional intermediaries as well as the role of museums as end-collectors. In the last decade, the business practices of major transactional intermediaries reflected a significant shift in customary practice, with attention newly focused on the provenance (ownership history) of objects consigned for sale and on long-standing concerns with an object\u27s condition and authorship. During the same time major museums developed new policies and practices applicable to new acquisitions and objects already in held in collections, focused in particular on archaeological objects and ancient art, as well as paintings present in European countries subject to the Nazi regime between 1932 and 1945. The Essay argues that, in both cases, law furnished the backdrop to significant shifts in customary practice, augmented by heightened public knowledge and concern. Custom evolved in response to salient episodes of enforcement of the law, which furnished further rallying points for newly broadened or awakened public interest and concern. The relationships explored in this Essay are relevant to ongoing debate about the merits of the underlying law. In the United States, it has long been true that nemo dat quod non habet—no one can give what one does not have—with the consequence that a thief cannot convey good title. The subsequent transferees lack good title and are not insulated against claims by the rightful owner even when the transferees acted in good faith. To be sure, an elapsed statute of limitations may furnish a defense, as may the equitable doctrine of laches. Prior scholarship notes that the United States is unusual, but not unique, because it does not recognize any good-faith purchaser defense in this context and because it does not require that the rightful owner of a stolen object compensate the good-faith purchaser as a condition of obtaining the return of the object. However, this scholarship does not acknowledge (or does not emphasize) the significance of transactional intermediaries within art markets or the operation of customary practices of museums and transactional intermediaries. This Essay thus adds the context requisite to evaluating the merits of the relevant law