Publications

This paper proposes a practical and scalable technique for point-to-point routing in wireless sensornets. This method, called Beacon Vector Routing (BVR), assigns coordinates to nodes based on the vector of distances (hop count) to a small set of beacons, and then defines a distance metric on these coordinates. Packets are routed greedily, being forwarded to the next hop that is the closest (according to this beacon vector distance metric) to the destination. This approach is evaluated through both simulation and a prototype implementation on motes.

Human trajectory forecasting is an inherently multi-modal problem. Uncertainty in future trajectories stems from two sources: (a) sources that are known to the agent but unknown to the model, such as long term goals and (b) sources that are unknown to both the agent and the model, such as the intent of other agents and irreducible randomness in decisions. We propose to factorize this uncertainty into its epistemic and aleatoric sources. We model the epistemic uncertainty through multimodality in long term goals and the aleatoric uncertainty through multimodality in way-points and paths. To exemplify this dichotomy, we also propose a novel long term trajectory forecasting setting, with prediction horizons up to a minute, up to an order of magnitude longer than prior works. Finally, we present Y-net, a scene compliant trajectory forecasting network that exploits the proposed epistemic and aleatoric structure for diverse trajectory predictions across long prediction horizons. Y-net significantly improves previous state-of-the-art performance on both (a) The short prediction horizon setting on the Stanford Drone (31.7% in FDE) and ETH/UCY datasets (7.4% in FDE) and (b) The proposed long horizon setting on the re-purposed Stanford Drone and Intersection Drone datasets.

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

No abstract is provided for this article.

Synthetic strategies to access both regiorandom and regioregular polythiophenes containing electron-withdrawing carboxylate substituents have been developed. Although these polymers have extended conjugation lengths, they provide better oxidative doping stability than conventional polythiophenes due to the lowering of the HOMO energy levels by approximately 0.5 eV. These materials are highly crystalline and exhibit very small π−π-stacking distances in the solid state. High charge mobilities are observed as a result of the close ordering of the polymer chains, and top-contact organic thin-film transistors (OTFTs) fabricated entirely in air had measured mobilities averaging 0.06 cm2/V·s with on/off ratios >105. Off currents in these devices remained low over a period of months, demonstrating the low propensity of these materials toward p-doping by molecular oxygen.

Abstract The evolutionary role of the so-called “changing-look” (CL) active galactic nucleus (AGN), which is characterized by spectral-type transitions within ∼10 yr, has been suggested in the past few years. By focusing on CL-AGNs having spectra similar to those of broad-line Seyfert 1 galaxies, some authors have proposed that CL-AGNs tend to be at a special evolutionary stage associated with intermediate-to-old stellar populations. Here we attempt to verify this evolutionary role by extending the sample to CL narrow-line Seyfert 1 (NLS1) galaxies, which are believed to be “young” AGNs with a less massive supermassive black hole and high accretion rate. Combining the recent large NLS1 catalog provided by V. S. Paliya et al. and the fifth Sloan Digital Sky Survey (SDSS-V) DR19 spectral survey returns only three CL-NLS1s out of a parent sample of 884 objects, reinforcing the rarity of CL-NLS1s. Subsequent spectral analysis shows that the evolutionary role mentioned above still holds, although CL-NLS1s tend to occupy the young end of the intermediate-old population. Finally, we propose that off-center SDSS spectra caused by the “fiber drop” effect have great potential for determining the properties of the narrow-line region of NLS1s.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

GaN 1 − x As x alloys grown across the composition range by low temperature molecular beam epitaxy have great technological potential for photovoltaic applications owing to their strong absorption coefficient and wide tunability of band gap and band edges. We found that amorphous GaN1−xAsx alloys that are formed for the compositions x, in the range of x∼0.3–0.7 are stable up to 700 °C. This is surprising since growth of GaN1−xAsx above 400 °C results in phase segregation. At annealing temperatures higher than 700 °C the alloy phase segregates into GaAs:N and GaN:As. The relative size of the nanocrystals depends on the initial film composition and annealing conditions.

Abstract The developmental patterns of subcortical brain volumes in males and females observed in previous studies have been inconsistent. To help resolve these discrepancies, we examined developmental trajectories using three independent longitudinal samples of participants in the age-span of 8-22 years (total 216 participants and 467 scans). These datasets, including Pittsburgh (PIT; University of Pittsburgh, USA), NeuroCognitive Development (NCD; University of Oslo, Norway), and Orygen Adolescent Development Study (OADS; The University of Melbourne, Australia), span three countries and were analyzed together and in parallel using mixed-effects modeling with both generalized additive models and general linear models. For all regions and across all samples, males were found to have significantly larger volumes as compared to females, and significant sex differences were seen in age trajectories over time. However, direct comparison of sample trajectories and sex differences identified within samples were not consistent. The trajectories for the amygdala, putamen, and nucleus accumbens were most consistent between the three samples. Our results suggest that even after using similar preprocessing and analytic techniques, additional factors, such as image acquisition or sample composition may contribute to some of the discrepancies in sex specific patterns in subcortical brain changes across adolescence, and highlight region-specific variations in congruency of developmental trajectories.

Iron-doped nickel (oxy)­hydroxide catalysts (Fe x Ni1–x OOH) exhibit high electrocatalytic behavior for the oxygen evolution reaction in base. Recent findings suggest that the incorporation of Fe3+ into a NiOOH lattice leads to nearly optimal adsorption energies for OER intermediates on active Fe sites. Utilizing electrochemical impedance spectroscopy and activation energy measurements, we find that pure NiOOH and FeOOH catalysts exhibit exceedingly high Faradaic resistances and activation energies 40–50 kJ/mol−1 higher than those of the most active Fe x Ni1–x OOH catalysts. Furthermore, the most active Fe x Ni1–x OOH catalysts in this study exhibit activation energies that approach those previously reported for IrO2 OER catalysts.

Adv. Healthcare Mater. 2023, 12, 2201588 https://doi.org/10.1002/adhm.202201588 In the published version of this article, the cytoskeleton image in Figure 4A on the far right (SF-TGF-β1, E7) is a duplicate of Figure 7B in an earlier publication from the same authors (Z. N. Mao, X. W. Bi, F. Ye, X. Shu, L. Sun, J. Guan, R. O. Ritchie, S. J. Wu, ACS Biomater. Sci. Eng. 2020, 6(8), 4512–4522. https://doi.org/10.1021/acsbiomaterials.0c00752), due to a mistake by the authors when compiling the images for their figures from the same file which contained all their images of their cytoskeleton/nuclear staining tests. The new Figure 4 to replace is shown below. The authors confirm that this correction does not affect the overall results and conclusions from this work. The authors apologize for any inconvenience caused.