Multi-Fault Tolerance for Cartesian Data Distributions

Faults are expected to play an increasingly important role in how algorithms and applications are designed to run on future extreme-scale systems. Algorithm-based fault tolerance is a promising approach that involves modifications to the algorithm to recover from faults with lower overheads than replicated storage and a significant reduction in lost work compared to checkpoint-restart techniques. Fault-tolerant linear algebra algorithms employ additional processors that store parities along the dimensions of a matrix to tolerate multiple, simultaneous faults. Existing approaches assume regular data distributions (blocked or block-cyclic) with the failures of each data block being independent. To match the characteristics of failures on parallel computers, we extend these approaches to mapping parity blocks in several important ways. First, we handle parity computation for generalized Cartesian data distributions with each processor holding arbitrary subsets of blocks in a Cartesian-distributed array. Second, techniques to handle correlated failures, i.e., multiple processors that can be expected to fail together, are presented. Third, we handle the colocation of parity blocks with the data blocks and do not require them to be on additional processors. Several alternative approaches, based on graph matching, are presented that attempt to balance the memory overhead on processors while guaranteeing the same fault tolerance properties as existing approaches that assume independent failures on regular blocked data distributions. Evaluation of these algorithms demonstrates that the additional desirable properties are provided by the proposed approach with minimal overhead.     

Impact of the injection‐level‐dependent lifetime on Voc,FF, ideality m,J02, and the dim light response in a commercial PERC cell

The injection‐level‐dependent (ILD) lifetime of the silicon wafer impacts many characteristics of the final photovoltaic cell. While efficiency is commonly understood to be impacted by the silicon bulk lifetime (at the maximum power point injection level), this work demonstrates the wide ranging impacts of ILD lifetime on the V_oc, the fill factor (FF), the diode ideality factor m, and the dim light response. Instead of a two‐diode model, we utilize a boundary + ILD bulk lifetime model to analyze a commercial passivated emitter rear contact (PERC) cell featuring an AlO_x dielectric rear passivation. The ILD lifetime is directly measured and used to calculate the bulk recombination current across injection levels. With this boundary + ILD lifetime model, we demonstrate the role of the ILD lifetime on many cell parameters in this PERC cell. For most high efficiency commercial p‐type monocrystalline solar cells, the typically lower bulk lifetime at the maximum power point versus the lifetime at the open circuit point reduces the measured FF and pseudo‐FF. This work illustrates that for a commercial PERC cell with AlO_x rear passivation, the ILD lifetime is the primary mechanism behind reduced FF, ideality factors greater than 1, and the source of the J₀₂ term in the two‐diode model. The crucial implications of this work are not only to better understand commercial PERC cell loss mechanisms but also to encourage a focus on different metrics in cell diagnostics. One such metric is the V_oc at 0.1 or 0.05 suns. Copyright © 2016 John Wiley & Sons, Ltd.     

Probing stress effects in HfO2 gate stacks with time dependent measurements

Effects of constant voltage stress (CVS) on gate stacks consisting of an ALD HfO₂ dielectric with various interfacial layers were studied with time dependent sensing measurements: DC I–V, pulse I–V, and charge pumping (CP) at different frequencies. The process of injected electron trapping/de-trapping on pre-existing defects in the bulk of the high-κ film was found to constitute the major contribution to the time dependence of the threshold voltage (V_t) shift during stress. The trap generation observed with the low frequency CP measurements is suggested to occur within the interfacial oxide layer or the interfacial layer/high-κ interface, with only a minor effect on V_t.     

Contaminant blubber burdens in Atlantic bottlenose dolphins (Tursiops truncatus) from two southeastern US estuarine areas: Concentrations and patterns of PCBs, pesticides, PBDEs, PFCs, and PAHs

Polychlorinated biphenyls (PCBs), chlorinated pesticides (i.e., dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordanes (CHLs), dieldrin, hexachlorobenzene (HCB), and mirex), polybrominated diphenyl ethers (PBDEs), perfluorinated chemicals (PFCs), and polyaromatic hydrocarbons (PAHs) were measured in blubber biopsy samples collected from 139 wild bottlenose dolphins (Tursiops truncatus) during 2003-2005 in Charleston (CHS), SC and the Indian River Lagoon (IRL), FL. Dolphins accumulated a similar suite of contaminants with ∑ PCB dominating (CHS 64%, IRL 72%), followed by ∑ DDT (CHS 20%, IRL 17%), ∑ CHLs (CHS 7%; IRL 7%), ∑ PBDE (CHS 4%, IRL 2%), PAH at 2%, and dieldrin, PFCs and mirex each 1% or less. Together ∑ PCB and ∑ DDT concentrations contributed ∼ 87% of the total POCs measured in blubber of adult males. ∑ PCBs in adult male dolphins exceed the established PCB threshold of 17 mg/kg by a 5-fold order of magnitude with a 15-fold increase for many animals; 88% of the dolphins exceed this threshold. For male dolphins, CHS (93,980 ng/g lipid) had a higher ∑ PCBs geomean compared to the IRL (79,752 ng/g lipid) although not statistically different. In adult males, the PBDE geometric mean concentration was significantly higher in CHS (5920 ng/g lipid) than the IRL (1487 ng/g). Blubber ∑ PFCs concentrations were significantly higher in CHS dolphins. In addition to differences in concentration of PCB congeners, ∑ PBDE, TEQ, ∑ CHLs, mirex, dieldrin, and the ratios ∑ DDE/∑DDT and trans-nonachlor/cis-nonachlor were the most informative for discriminating contaminant loads in these two dolphin populations. Collectively, the current ∑ PCB, ∑ DDT, and ∑ PBDEs blubber concentrations found in CHS dolphins are among the highest reported values in marine mammals. Both dolphin populations, particularly those in CHS, carry a suite of organic chemicals at or above the level where adverse effects have been reported in wildlife, humans, and laboratory animals warranting further examination of the potential adverse effects of these exposures.     

The Locus of Redundant-Targets and Nontargets Effects: Evidence From the Psychological Refractory Period Paradigm.

In target detection tasks, responses are faster when displays have 2 targets (redundant-targets effect; RTE) and slower when they have no targets (nontargets effect; NTE) relative to displays with a single target. The psychological refractory period paradigm was used to localize these effects. In Experiment 1, participants classified tones as high or low and then classified letters as targets or nontargets after a short or long stimulus onset asynchrony (SOA). The magnitudes of the RTE and NTE did not depend on SOA. In Experiment 2, the order of the tasks was reversed, and at short SOAs the RTE and NTE had similar magnitudes for both tone discrimination and target detection responses. These findings suggest that the RTE and NTE arise during response selection. Interactive effects of tone pitch with the number and type of target features were also observed, and these were tentatively interpreted as synesthetic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The internship supply-demand imbalance: The APPIC perspective.

The internship has long been considered the capstone experience in the sequence of doctoral education in professional psychology. Since at least 1999, the number of available internship positions in the United States and Canada has been outstripped by the number of students seeking these positions. The resulting imbalance between supply and demand for internship positions has grown substantially since 2002 and now should be considered to have reached crisis proportions. Although no complete solution to this imbalance is imminently feasible, a comprehensive approach to addressing the crisis requires that both the supply of internships and the growth in demand be addressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Three‐Dimensionally Ordered Macroporous Polymeric Materials by Colloidal Crystal Templating for Reversible CO2 Capture

The design and preparation of porous materials with controlled structures and functionalities is crucial to a variety of absorption‐ or separation‐relevant applications, including CO₂ capture. Here, novel functional polymeric materials with three‐dimensionally ordered macroporous (3DOM) structures are prepared by using colloidal crystals as templates using relatively simple, rapid, and inexpensive approaches. These ordered structures are used for the reversible CO₂ capture from ambient air by humidity swing. Typically, the colloidal crystal template is synthesized from polymer latex particles of poly(methyl methacrylate) (PMMA) or polystyrene (PS). To maintain the functionality of the material, it is important to prevent the porous structure collapsing, which can occur by the hydrolysis of the ester bonds in conventional crosslinkers under basic conditions. This hydrolysis can be prevented by using a water‐soluble crosslinker containing two quaternary ammonium moieties, which can be used to prepare stable porous crosslinked polymers with the monomer (vinylbenzyl)trimethylammonium chloride (VBTMACl) and using a PMMA‐based colloidal crystal template. The hydroxide‐containing monomer and dicationic crosslinker are synthesized from their chloride precursors, avoiding the ion‐exchange step which causes shrinkage of the pores. An analysis of different methods for infiltrating the monomer solution into the colloidal crystal template shows that infiltration using capillary forces leads to fewer defects than infiltration under a partial vacuum. In addition, functional macroporous films with micrometer thickness are prepared from a template of PS‐based colloidal crystals in a thin film. In general, the colloidal crystal templated materials showed improved CO₂ absorption/desorption rates and swing sizes compared to a commercially available material with similar functional groups. This work could easily be extended to create a new generation of ordered macroporous polymeric materials with tunable functionalities for other applications.     

The aggression paradox: Understanding links among aggression, sensation seeking, and the consideration of future consequences.

Four studies involving 573 female and 272 male college students demonstrated that multiple forms and measures of aggression were associated with high levels of sensation seeking, impulsivity, and a focus on the immediate consequences of behavior. Multiple regression analyses and structural equation models supported a theoretical model based on the general aggression model (C. A. Anderson & B. J. Bushman, 2002), positing that hostile cognition and negative affect mediate the relationships between the aforementioned individual differences and aggression. Sensation seeking also predicted a desire to engage in physical and verbal aggression. The final study demonstrated that relative to those scoring low, individuals scoring high on the consideration of future consequences are only less aggressive when aggression is likely to carry future costs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MVA Processing of Speech Features

In this paper, we investigate a technique consisting of mean subtraction, variance normalization and time sequence filtering. Unlike other techniques, it applies auto-regression moving-average (ARMA) filtering directly in the cepstral domain. We call this technique mean subtraction, variance normalization, and ARMA filtering (MVA) post-processing, and speech features with MVA post-processing are called MVA features. Overall, compared to raw features without post-processing, MVA features achieve an error rate reduction of 45% on matched tasks and 65% on mismatched tasks on the Aurora 2.0 noisy speech database, and an average 57% error reduction on the Aurora 3.0 database. These improvements are comparable to the results of much more complicated techniques even though MVA is relatively simple and requires practically no additional computational cost. In this paper, in addition to describing MVA processing, we also present a novel analysis of the distortion of mel-frequency cepstral coefficients and the log energy in the presence of different types of noise. The effectiveness of MVA is extensively investigated with respect to several variations: the configurations used to extract and the type of raw features, the domains where MVA is applied, the filters that are used, the ARMA filter orders, and the causality of the normalization process. Specifically, it is argued and demonstrated that MVA works better when applied to the zeroth-order cepstral coefficient than to log energy, that MVA works better in the cepstral domain, that an ARMA filter is better than either a designed finite impulse response filter or a data-driven filter, and that a five-tap ARMA filter is sufficient to achieve good performance in a variety of settings. We also investigate and evaluate a multi-domain MVA generalization