DETONATION CLASSIFICATION FROM ACOUSTIC SIGNATURE WITH THE RESTRICTED BOLTZMANN MACHINE

We compare the recently proposed Discriminative Restricted Boltzmann Machine (DRBM) to the classical Support Vector Machine (SVM) on a challenging classification task consisting in identifying weapon classes from audio signals. The three weapon classes considered in this work (mortar, rocket, and rocket‐propelled grenade), are difficult to reliably classify with standard techniques because they tend to have similar acoustic signatures. In addition, specificities of the data available in this study make it challenging to rigorously compare classifiers, and we address methodological issues arising from this situation. Experiments show good classification accuracy that could make these techniques suitable for fielding on autonomous devices. DRBMs appear to yield better accuracy than SVMs, and are less sensitive to the choice of signal preprocessing and model hyperparameters. This last property is especially appealing in such a task where the lack of data makes model validation difficult.     

The three-dimensional model of Dictyostelium discoideum racE based on the human rhoA-GDP crystal structure

The three-dimensional structure of racE was modeled using several homologous small G proteins, and the best model obtained using the human rhoA as modeling template is reported. The three-dimensional fold of the racE model is remarkably similar to the cellular form of human ras p21 crystal structure. Its secondary structure consists of six alpha-helices, six beta-strands and three 3(10) helices. The model retains its secondary structure after a 300 K, 300 ps molecular dynamics (MD) simulation. Important domains of the protein include its effector loop (residues 34-46), the insertion domain (residues 121-136), and the polybasic motif (between 210 and 220) not modeled in the current structure. The effector loop is inherently flexible and the structure docked with GDP exhibits the effector loop moving significantly closer to the nucleotide binding pocket, forming a tighter complex with the bound GDP. The mobility of the effector loop is conferred by a single residue 'hinge' point at residue 34Asp, also allowing the Switch I region, immediately preceding the effector loop, to be equally mobile. In comparison, the Switch II region shows average mobility. The insertion domain is highly flexible, with the insertion taking the form of a helical domain, with several charged residues forming a complex charged interface over the entire insertion region. While the GDP moiety is loosely held in the active site, the metal cation is extensively co-ordinated. The critical residue 38Thr exhibits high mobility, and is seen interacting directly with the metal ion at a distance of 2.64 A, and indirectly via an intervening water molecule. 64Gln, a key residue involved in GTP hydrolysis in ras, is seen facing the beta-phosphate group and the metal ion. Certain residues (i.e. 51Asn, 38Thr and 65Glu) exhibit unique characteristics and these residues, together with 158Val, may play important roles in the maintenance of the protein's integrity and function. There is strong consensus of secondary structural elements between models generated using various templates, such as h-rac1, h-rhoA and h-cdc42 bound to RhoGDI, all sharing only 50-55% sequence identity with racE, which suggests that this model is in all probability an accurate prediction of the true tertiary structure of racE.     

Synthesis and spectral properties of Ce[Ag(CN)2]3

Cerium ion luminescence in crystalline hosts forms the basis of many blue phosphor and scintillator technologies. We report the synthesis of luminescent single crystals of cerium dicyanoargentate. The luminescence properties are characterized using both steady-state and time-resolved spectroscopy. The broad, overlapping dicyanoargentate and Ce³⁺ emissions are decomposed into three Gaussians, revealing the characteristic dicyanoargentate emission at 350 nm while the Ce³⁺ 5d–4f transitions are observed at 359 nm and 391 nm. Excitation measurements show that the 4f–5d Ce³⁺ absorption overlaps the 320 nm emission of the dicyanoargentate ions, leading to a strong coupling between the dicyanoargentate energy donors and Ce³⁺ acceptors. We conclude that the cerium is excited through an energy transfer process from the dicyanoargentate species, resulting in strong room temperature luminescence.     

Corrosion protective performances of commercial low-VOC epoxy/urethane coatings on hot-rolled 1010 mild steel

The protective properties of low-VOC epoxy/urethane paint systems of commercial grade have been investigated using a variety of techniques such as electrochemical impedance spectroscopy (EIS). One epoxy-polyamide mastic/urethane, three high-solid epoxy-amine/urethane coatings, one solvent-free epoxy-amine/urethane, one water-based epoxy-amine and one high-VOC alkyd paint system (used as paint reference system) were applied on hot-rolled 1010 mild steel panels and exposed for up to 2000 h in the salt spray cabinet (SSC) or for 1 year at an outdoor marine test site. These paints were tested for their barrier properties, corrosion-induced adhesion loss and visual defects, as well as for their flexibility and resistance to direct impact. The barrier properties increased in the following order: alkyd相似文献   

The effect of climbing bean adoption on the welfare of smallholder common bean growers in Rwanda

This paper assessed the effect of climbing bean adoption on the welfare of the bean growers in Rwanda, using four indicators: per capita consumption expenditure, poverty head count, quantity of bean consumed per person and food security. The analysis was based on cross sectional data from a nationally representative survey of bean growers, conducted in 2011. Instrumental variables and control function approaches were used to address the endogeneity of climbing bean adoption decisions in household welfare outcomes. Results demonstrated that investments in climbing bean research and dissemination efforts contributed significantly to improve household welfare. One additional kilogram of climbing bean seed planted raises per capita consumption expenditure by 0.9% and that of bean consumption by 2.8%, and increases the probability that a household is food secure by 0.6% while decreasing the likelihood of being poor by 0.6%. These findings highlight the important role climbing bean adoption can play in reducing food insecurity and poverty in land constrained areas.     

Beta PDGFR-IgG chimera demonstrates that human beta PDGFR Ig-like domains 1 to 3 are sufficient for high affinity PDGF BB binding

To localize human beta PDGFR binding determinants, we constructed a fusion protein comprising beta PDGFR Ig-like domains 1 to 3 and an IgG1 Fc domain (beta PDGFR-HFc). beta PDGFR-HFc was expressed as a 200 kDa dimeric molecule and contained Fc epitopes as demonstrated by anti-mouse Fc antibody recognition. Scatchard analysis revealed that PDGF BB possessed a dissociation constant of 1.5 nM for beta PDGFR-HFc. Thus, beta PDGFR Ig-like domains 1 to 3 are sufficient for high affinity PDGF BB binding. We exploited this fusion protein technology to identify and characterize beta PDGFR antagonists using a sensitive beta PDGFR immunosorbent assay. In this assay, beta PDGFR-HFc half-maximally bound to PDGF BB with an affinity of around 150 pM. Suramin, as well as bacterially expressed and refolded human alpha PDGFR domains 1-3, inhibited beta PDGFR-HFc binding to PDGF BB half-maximally at 25 microM and 10 nM respectively. Therefore, alpha PDGFR D1-3, like beta PDGFR D1-3, are sufficient for high affinity PDGF BB binding. Furthermore, the beta PDGFR-HFc immunosorbent assay will be useful to identify beta PDGFR antagonists as well as to study alpha and beta PDGFR substitution mutants which further map receptor binding determinants.     

Learning where to attend with deep architectures for image tracking

We discuss an attentional model for simultaneous object tracking and recognition that is driven by gaze data. Motivated by theories of perception, the model consists of two interacting pathways, identity and control, intended to mirror the what and where pathways in neuroscience models. The identity pathway models object appearance and performs classification using deep (factored)-restricted Boltzmann machines. At each point in time, the observations consist of foveated images, with decaying resolution toward the periphery of the gaze. The control pathway models the location, orientation, scale, and speed of the attended object. The posterior distribution of these states is estimated with particle filtering. Deeper in the control pathway, we encounter an attentional mechanism that learns to select gazes so as to minimize tracking uncertainty. Unlike in our previous work, we introduce gaze selection strategies that operate in the presence of partial information and on a continuous action space. We show that a straightforward extension of the existing approach to the partial information setting results in poor performance, and we propose an alternative method based on modeling the reward surface as a gaussian process. This approach gives good performance in the presence of partial information and allows us to expand the action space from a small, discrete set of fixation points to a continuous domain.