Blackfin处理器面向开源应用

在嵌入式应用中。随着“开源”C／C 代码越来越成为流行的用于替代基于版权算法的另一选择，挑战也随之而来。其中，最重要的问题是如何优化代码．使其在选定的处理器中更好地运行。本文将探讨开源算法在Blockfin处理器上的移植以及代码优化。     

Empirically derived subtypes of adolescent depression: Latent profile analysis of co-occurring symptoms in the Treatment for Adolescents with Depression Study (TADS).

A latent profile analysis was conducted on the co-occurring symptoms of 423 adolescents diagnosed with major depressive disorder as part of the Treatment for Adolescents with Depression Study (TADS), a multisite, randomized treatment trial. The participants had a mean (SD) age of 14.6 (1.5) years; of the sample, 45.6% was male and 73.8% was white. Scores on the primary subscales of Conners' Parent Rating Scale-Revised were used as indicators in the analysis. Five classes of symptoms best described the clinical presentation of adolescents enrolled in the TADS. Of the adolescents in the sample, 80% were assigned to classes with clinically significant elevations on 1 or more subscales of the Children's Depression Rating Scale-Revised. The 5 classes met empirical criteria for distinctiveness and were validated against clinical diagnoses, child-rated symptoms, and clinician-rated functional impairment. The findings are consistent with prior studies that showed a high rate of co-occurring symptoms among depressed adolescents. The discussion focuses on understanding subtypes and comorbidity in adolescent depression as well as the implications for treatment and for prevention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concealed weapon detection and visualization in a synthesized image

Images acquired by heterogeneous image sensors may provide complementary information about the scene, for instance, the visual image can provide personal identification information like the facial pattern while the infrared (IR) or millimeter wave image can detect the suspicious regions of concealed weapons. Usually, a technique, namely multiresolution pixel-level image fusion is applied to integrate the information from multi-sensor images. However, when the images are significantly different, the performance of the multiresolution fusion algorithms is not always satisfactory. In this study, a new strategy consisting of two steps is proposed. The first step is to use an unsupervised fuzzy k-means clustering to detect the concealed weapon from the IR image. The detected region is embedded in the visual image in the second step and this process is implemented with a multiresolution mosaic technique. Therefore, the synthesized image retains the quality comparable to the visual image while the region of the concealed weapon is highlighted and enhanced. The experimental results indicate the efficiency of the proposed approach.This material is based on part of the work carried out at the SPCR laboratory of Lehigh University and the work is partially supported by the U. S. Army Research Office under grant number DAAD19-00-1-0431. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred.     

Simulating the Child's Acquisition of the Lexicon and Syntax—Experiences With Babel

This paper describes the theory and implementation ofBabel, a system which explores the hypothesis that much of the differences in the world's languages may be characterized by the inventory and properties of the lexical items and functional categories of those languages. The structure ofBabel assumes that functional categories are originally lacking in a child's syntax, and are acquired through a statistical induction process of lexical acquisition.Babel then uses information induced from the structure of the lexicon to create a model of syntax via a deductive, rule-based process. This model makes a number of predictions about the time course of language acquisition. These predictions are tested by runningBabel as a simulation of child language acquisition, using large samples of adult speech to children as input. The simulation results are shown to highly correlate to longitudinal studies of child language acquisition in English and Polish. Finally, the approach to handling noisy data withBabel is detailed.     

A molecular dynamics simulation of bacteriophage T4 lysozyme

An analysis of a 400 ps molecular dynamics simulation of the164 amino acid enzyme T4 lysozyme is presented. The simulationwas carried out with all hydrogen atoms modeled explicitly,the inclusion of all 152 crystallographic waters and at a temperatureof 300 K. Temporal analysis of the trajectory versus energy,hydrogen bond stability, r.m.s. deviation from the startingcrystal structure and radius of gyration, demonstrates thatthe simulation was both stable and representative of the averageexperimental structure. Average structural properties were calculatedfrom the enzyme trajectory and compared with the crystal structure.The mean value of the C displacements of the average simulatedstructure from the X-ray structure was 1.1 ± 0.1 Å;differences of the backbone and angles between the averagesimulated structure and the crystal structure were also examined.Thermal-B factors were calculated from the simulation for heavyand backbone atoms and both were in good agreement with experimentalvalues. Relationships between protein secondary structure elementsand internal motions were studied by examining the positionalfluctuations of individual helix, sheet and turn structures.The structural integrity in the secondary structure units waspreserved throughout the simulation; however, the A helix didshow some unusually high atomic fluctuations. The largest backboneatom r.m.s. fluctuations were found in non-secondary structureregions; similar results were observed for r.m.s. fluctuationsof non-secondary structure and angles. In general, the calculatedvalues of r.m.s. fluctuations were quite small for the secondarystructure elements. In contrast, surface loops and turns exhibitedmuch larger values, being able to sample larger regions of conformationalspace. The C difference distance matrix and super-positioninganalyses comparing the X-ray structure with the average dynamicsstructure suggest that a ‘hinge-bending’ motionoccurs between the N- and C-terminal domains.     

Investigation of bio-ethanol steam reforming over cobalt-based catalysts

The catalytic performance of cobalt catalysts supported on γ-Al₂O₃, TiO₂, ZrO₂ were studied for bio-ethanol steam reforming (BESR) reaction. The supported catalysts (10 wt%Co) were prepared by impregnation and characterized through Thermogravimetric analysis (TGA), H₂ chemisorption, laser Raman Spectroscopy, Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), and temperature-programmed reaction (TPRxn). The metallic cobalt sites were found to correlate with the BESR reaction activity. The reaction and H₂ chemisorption showed that ZrO₂ supported catalyst showed the best dispersion and best catalytic activity. Over the 10% Co/ZrO₂ catalyst, using a H₂O:EtOH:inert molar ratio of 10:1:75 and a GHSV = 5000 h⁻¹, 100% ethanol conversion and a yield of 5.5 mol H₂/mol EtOH were obtained at 550 °C and atmospheric pressure.     

Wear Mechanisms of Chromia Refractories in Slagging Gasifiers

The hot-face refractory lining is a key component of gasification systems. The refractory liner protects the gasification system from the high-temperature corrosive gaseous and from the molten slag environment associated with the conversion of carbon feedstocks. This paper will discuss the effect of gasifier operating conditions and carbon feedstock slag/ash chemistry on the refractory service life. Particular attention is focused on the wear mechanism of chromia refractories, determined through postmortem analysis of spent refractory bricks from service in gasifiers. Also presented is the behavior of a phosphate-containing chromia refractory with improved resistance to structural spalling.     

Phytotoxic properties of cnicin,a sesquiterpene lactone fromcentaurea maculosa (spotted knapweed)

Water and solvent extracts from the aerial tissues ofCentaurea maculosa, spotted knapweed, inhibited the root growth of lettuce. Column chromatography and lettuce bioassay of a chloroform extract led to the isolation of cnicin, a sesquiterpene lactone. Pure cnicin was bioassayed at 0, 1, 2, 4, 6, 8, and 10 mg/5 ml water with lettuce, created wheatgrass, bluebunch wheatgrass, rough fescue, western larch, lodgepole pine, and spotted knapweed. Germination was inhibited at one or more concentrations for all species except lodgepole pine and spotted knapweed. Growth, particularly of the roots, was retarded between 1 and 4 mg of cnicin. Lettuce, bluebunch wheatgrass, and spotted knapweed were inhibited significantly at all concentrations tested.     

Entanglement networks of 1,2-polybutadiene crosslinked in states of strain. IV. States of ease and stress–strain behavior

Linear 1,2-polybutadiene, glass transition temperature (T_g) ?18°C, is crosslinked at ?10°C, to ?20°C by γ irradiation while strained in simple extension, with extension, ratios (λ₀) from 1.2 to 2.7. After release, the sample retracts to a state of ease (λ_s) at room temperature. From equilibrium stress–strain measurements up to a stretch ratio relative to the state of ease (Λ) of 1.2, together with λ₀ and λ_s, the concentration of network strands terminated by trapped entanglements (νN) is calculated. For this purpose, a three-constant Mooney–Rivlin formulation is used, in which the entanglement network is described by Mooney–Rivlin coefficients C_1N and C_2N, whereas the crosslink networks is described by the coefficient C_1x only. The ratio ψ_N = C_2N/(C_1N + C_2N) is estimated from parallel studies of nonlinear stress relaxation of the uncrosslinked polymer, taking into account the thermal history before and during irradiation. For substantial degrees of crosslinking, i.e., for R_0′ = ν_x/ν_N > 0.4 (where ν_N is the concentration of network strands terminated by crosslinks), and for λ₀ < 1.8, C_2N agrees rather well with the value obtained from stress relaxation of the uncrosslinked polymer in the range of time scale where it is nearly independent of time (1.87 X 10⁵ pascals). The corresponding value of ν_N is 2.3 × 10^?4 moles/cm³, in good agreement with that obtained from viscoelastic measurements of the uncrosslinked polymer in the plateau zone (2.5 × 10^?4). However, for R_0′ ? 0.2, smaller values of C_2N and ν_N are obtained, indicating that for low degrees of crosslinking the entanglements are not completely trapped. Also, for higher values of λ₀, C_2N and ν_N turn out to be somewhat smaller. Similar, less extensive results were obtained previously on a 1,2-polybutadiene with somewhat higher vinyl content and a higher T_g. Crosslinked samples of both these polymers were subjected to equilibrium stress–strain measurements in simple elongation from the state of ease at higher strains up to Λ = 1.7. The results agreed closely with calculations from the three-constant Mooney–Rivlin theory.