Instance-Specific Accelerators for Minimum Covering

This paper presents the acceleration of minimum-cost covering problems by instance-specific hardware. First, we formulate the minimum-cost covering problem and discuss a branch & bound algorithm to solve it. Then we describe instance-specific hardware architectures that implement branch & bound in 3-valued logic and use reduction techniques similar to those found in software solvers. We further present prototypical accelerator implementations and a corresponding design tool flow. Our experiments reveal significant raw speedups up to five orders of magnitude for a set of smaller unate covering problems. Provided that hardware compilation times can be reduced, we conclude that instance-specific acceleration of hard minimum-cost covering problems will lead to substantial overall speedups.     

Stressors, resources, and strain at work: A longitudinal test of the triple-match principle.

[Correction Notice: An erratum for this article was reported in Vol 92(1) of Journal of Applied Psychology (see record 2006-23339-016). The issue number at the upper left corner of the title page (p. 1359) is wrongly stated as 5 rather than 6. Furthermore, in Table 1 (p. 1362), the value in Column 12, Row 4 (Emo resources) should be -.07 rather than -0.7.] Two longitudinal studies investigated the issue of match between job stressors and job resources in the prediction of job-related strain. On the basis of the triple-match principle (TMP), it was hypothesized that resources are most likely to moderate the relation between stressors and strains if resources, stressors, and strains all match. Resources are less likely to moderate the relation between stressors and strains if (a) only resources and stressors match, (b) only resources and strains match, or (c) only stressors and strains match. Resources are least likely to moderate the relation between stressors and strains if there is no match among stressors, resources, and strains. The TMP was tested among 280 and 267 health care workers in 2 longitudinal surveys. The likelihood of finding moderating effects was linearly related to the degree of match, with 33.3% of all tested interactions becoming significant when there was a triple match, 16.7% when there was a double match, and 0.0% when there was no match. Findings were most consistent if there was an emotional match or a physical match. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pulse-driven Josephson digital/analog converter [voltage standard]

The authors have designed and demonstrated a pulse-driven Josephson digital/analog converter. When used as a programmable voltage standard, this device can synthesize metrologically accurate ac waveforms as well as stable dc voltages. We show through simulations that Josephson quantization produces a nearly ideal quantization noise spectrum when a junction is driven with a typical waveform produced by a digital code generator. This technique has been demonstrated in preliminary experiments with arrays of 1000 junctions clocked at frequencies up to 6 Gb/s, where sine waves of a few millivolts in amplitude were synthesized at frequencies up to 1 MHz     

Optimization and Adaptation of Error Control Algorithms for Wireless ATM

A common problem of all wireless digital datatransmission systems is the bit error rates of the radiosubsystem, which can be several orders of magnitudehigher than for a wire- or fiber-based technology. Forward error correction (FEC), automaticrepeat request (ARQ), and interleaving are used as meansto improve throughput and bandwidth efficiency. Thispaper presents some considerations on the optimization and adaptation of these algorithms with focuson recent wireless ATM developments. The optimization,with respect to the target bit error rate and themapping of the wireless connection quality to the ATM quality of service (QoS) concept, is discussedin detail. In addition to the theoretical evaluation,which is verified by extensive simulations, we presentcomprehensive architecture and implementation considerations on the design of an adaptiveerror control system for a wireless ATMnetwork.     

Understanding the Catalytic Conversion of Automobile Exhaust Emissions Using Model Catalysts: CO + NO Reaction on Pd(111)

The CO + NO reaction is one of the profoundly important reactions that take place on Pd-based industrial three-way catalysts (TWC). In this review, we discuss results from polarization modulation infrared reflection absorption spectroscopy (PM-IRAS) and conventional IRAS experiments on CO adsorption, NO adsorption and the CO + NO reaction on a Pd(111) model catalyst surface within a wide range of pressures (10^?6–450 Torr) and temperatures (80–650 K). It will be shown that these studies allow for a detailed understanding of the adsorption behavior of these species as well as the nature of the products that are formed during their reaction under realistic catalytic conditions. CO adsorption experiments on Pd(111) at elevated pressures reveal that CO overlayers exhibit similar adsorption structures as found for ultrahigh vacuum (UHV) conditions. On the other hand, in the case of the CO + NO reaction on Pd(111), the pressure dependent formation of isocyanate containing species' was observed. The importance of this observation and its effects on the improvement of the catalytic NO _x abatement is discussed. The kinetics of the CO + NO reaction on Pd(111) were also investigated and the factors affecting its selectivity are addressed.