Neural Collaborative Filtering

In recent years, deep neural networks have yielded immense success on speech recognition, computer vision and natural language processing. However, the exploration of deep neural networks on recommender systems has received relatively less scrutiny. In this work, we strive to develop techniques based on neural networks to tackle the key problem in recommendation -- collaborative filtering -- on the basis of implicit feedback. Although some recent work has employed deep learning for recommendation, they primarily used it to model auxiliary information, such as textual descriptions of items and acoustic features of musics. When it comes to model the key factor in collaborative filtering -- the interaction between user and item features, they still resorted to matrix factorization and applied an inner product on the latent features of users and items. By replacing the inner product with a neural architecture that can learn an arbitrary function from data, we present a general framework named NCF, short for Neural network-based Collaborative Filtering. NCF is generic and can express and generalize matrix factorization under its framework. To supercharge NCF modelling with non-linearities, we propose to leverage a multi-layer perceptron to learn the user-item interaction function. Extensive experiments on two real-world datasets show significant improvements of our proposed NCF framework over the state-of-the-art methods. Empirical evidence shows that using deeper layers of neural networks offers better recommendation performance.Comment: 10 pages, 7 figure

Field Measurements Of Blade Stresses On Industrial Turbomachines

PaperPg. 23-34.High blade stresses can be induced in axial compressors by various asymmetrical flow conditions or adverse working conditions. A series of measurements were carried out on industrial and gas turbine axial compressors. After a brief review of the various measuring methods, test results are presented and commented. The information gained refers to various working conditions, such as rotating stall, surging, partial injection of the turbine of superchargers for Diesel engines as well as to the influence of the wake of blading, especially for compressors with movable guide vanes. The influence of lacing wires on axial compressor bladings is presented and commented with respect to efficiency loss and increase of noise level

Gene induction during differentiation of human monocytes into dendritic cells: an integrated study at the RNA and protein levels

Changes in gene expression occurring during differentiation of human monocytes into dendritic cells were studied at the RNA and protein levels. These studies showed the induction of several gene classes corresponding to various biological functions. These functions encompass antigen processing and presentation, cytoskeleton, cell signalling and signal transduction, but also an increase in mitochondrial function and in the protein synthesis machinery, including some, but not all, chaperones. These changes put in perspective the events occurring during this differentiation process. On a more technical point, it appears that the studies carried out at the RNA and protein levels are highly complementary.Comment: website publisher: http://www.springerlink.com/content/ha0d2c351qhjhjdm

A new lab facility for measuring bidirectional reflectance/emittance distribution functions of soils and canopies

Recently, a laboratory measurement facility has been realized for assessing the anisotropic reflectance and emittance behaviour of soils, leaves and small canopies under controlled illumination conditions. The facility consists of an ASD FieldSpec 3 spectroradiometer covering the spectral range from 350 – 2500 nm at 1 nm spectral sampling interval. The spectroradiometer is deployed using a fiber optic cable with either a 1°, 8° or 25° instantaneous field of view (IFOV). These measurements can be used to assess the plant pigment (chlorophyll, xanthophyll, etc.) and non-pigment system (water, cellulose, lignin, nitrogen, etc.). The thermal emittance is measured using a NEC TH9100 Infrared Thermal Imager. It operates in a single band covering the spectral range from 8 – 14 mm with a resolution of 0.02 K. Images are 320 (H) by 240 (V) pixels with an IFOV of 1.2 mrad. A 1000 W Quartz Tungsten Halogen (QTH) lamp is used as illumination source, approximating the radiance distribution of the sun. This one is put at a fixed position during a measurement session. Multi-angular measurements are achieved by using a robotic positioning system allowing to perform either reflectance or emittance measurements over almost a complete hemisphere. The hemisphere can be sampled continuously between 0° and 80° from nadir and up to a few degrees from the hot-spot configuration (depending on the IFOV of the measurement device) for a backscattering target. Measurement distance to targets can be varied between 0.25 and 1 m, although with a distance of more than 0.6 m it is not possible to cover the full hemisphere. The goal is to infer the BRDF (bidirectional reflectance distribution function) and BTDF (bidirectional thermal distribution function) from these multi-angular measurements for various surface types (like soils, agricultural crops, small tree canopies and artificial objects) and surface roughness. The steering of the robotic arm and the reading of the spectroradiometer and the thermal camera are all fully automated

Seasonal Climatology of Hydrographic Conditions in the Upwelling Region Off Northern Chile

Over 30 years of hydrographic data from the northern Chile (18°S-24°S) upwelling region are used to calculate the surface and subsurface seasonal climatology extending 400 km offshore. The data are interpolated to a grid with sufficient spatial resolution to preserve crossshelf gradients and then presented as means within four seasons: austral winter (JulySeptember), spring (October-December), summer (January-March), and fall (April-June). Climatological monthly wind forcing, surface temperature, and sea level from three coastal stations indicate equatorward (upwelling favorable) winds throughout the year, weakest in the north. Seasonal maximum alongshore wind stress is in late spring and summer (DecemberMarch). Major water masses of the region are identified in climatological T-S plots and their sources and implied circulation discussed. Surface fields and vertical transects of temperature and salinity confirm that upwelling occurs year-round, strongest in summer and weakest in winter, bringing relatively fresh water to the surface nearshore. Surface geostrophic flow nearshore is equatorward throughout the year. During summer, an anticyclonic circulation feature in the north which extends to at least 200 rn depth is evident in geopotential anomaly and in both temperature and geopotential variance fields. Subsurface fields indicate generally poleward flow throughout the year, strongest in an undercurrent near the coast. This undercurrent is strongest in summer and most persistent and organized in the south (south of 21°S). A subsurface oxygen minimum, centered at ~250 m, is strongest at lower latitudes. Low-salinity subsurface water intrudes into the study area near 100 m, predominantly in offshore regions, strongest during summer and fall and in the southernmost portion of the region. The climatological fields are compared to features off Baja within the somewhat analogous California Current and to measurements from higher latitudes within the Chile-Peru Current system. Copyright 2001 by the American Geophysiccal Union

Nanogranular MgB2 thin films on SiC buffered Si substrates prepared by in-situ method

MgB2 thin films were deposited on SiC buffered Si substrates by sequential electron beam evaporation of B-Mg bilayer followed by in-situ annealing. The application of a SiC buffer layer enables the maximum annealing temperature of 830 C. The Transmission Electron Microscopy analysis confirms the growth of a nanogranular MgB2 film and the presence of a Mg2Si compound at the surface of the film. The 150-200 nm thick films show a maximum zero resistance critical temperature TC0 above 37 K and a critical current density JC ~ 106 A/cm2 at 11K.Comment: 7 pages, 6 figures, submitted to Applied Physics Letter

Seasonal and interannual variablity of pigment concentrations across a California Current frontal zone

Previously published physical and biological data document a zonally oriented frontal region within the California Current system separating colder and more eutrophic water north of ≈33°N from warmer; more stratified, and oligotrophic water farther to the south. Satellite images of phytoplankton pigment from the coastal zone color scanner from 1979-1983 and 1986 are used to examine the seasonal and interannual variability of both the latitudinal position of this front and the pigment concentrations associated with it. Many temporal and spatial characteristics of the pigment structure are repeated in different years, and a general seasonal cycle is described. Variations in the frontal structure are controlled primarily by changes in pigment concentrations north of the front. Seasonality is minimum south of the front where concentrations remain low (2.0 mg m⁻³) are present north of the front. Lower pigment concentrations within the sampled region (0.5-1.0 mg m⁻³) north of the front in mid-late summer (June-August), resulting from a seasonal shift in the cross-shelf distribution of pigment, reduce and often eliminate the pigment gradient forming the front. Concentrations greater than 1.0 mg m⁻³ typically extend 150-250 km farther offshore in spring (April) than in summer (June-July). Superimposed on this general seasonality is strong interannual variability in the magnitude of the frontal gradient, its latitudinal position, and the seasonal development of higher biomass in regions north of the front. Pigment concentrations during the El Niño year of 1983 are distinctly lower than those of other years. The patterns evident in the satellite data are compared with available in situ measured hydrographic data and nutrient and phytoplankton concentrations. A comparison of the seasonal and interannual variability of these patterns to surface wind shows little direct relation between frontal strength or position and wind forcing.Keywords: phytoplankton pigment, California CurrentKeywords: phytoplankton pigment, California Curren

Comparison of velocity estimates from advanced very high resolution radiometer in the Coastal Transition Zone

Two methods of estimating surface velocity vectors from advanced very high resolution radiometer (AVHRR) data were applied to the same set of images and the results were compared with in situ and altimeter measurements. The first method used and automated feature –tracking algorithm and the second method used an inversion of the heat equation. The 11 images were from 3 days in July 1988 during the Coastal Transition Zone field program and the in situ data included acoustic Doppler current profiler (ADCP) vectors and velocities from near surface drifters. The two methods were comparable in their degree of agreement with the in situ data, yielding velocity magnitudes that were 30-50% less than drifter and ADCP velocities measured at 15-20 m depth, with rms directional differences of about 60°. These differences compared favorably with a baseline difference estimate between ADCP vectors interpolated to drifter locations within a well-sampled region. High correlations between the AVHRR estimates and the coincident Geosat geostrophic velocity profiles suggested that the AVHRR methods adequately resolved the important flow features. The flow field was determined to consist primarily of a meandering southward flowing current, interacting with several eddies, including a strong anticyclonic eddy to the north of the jet. Incorporation of sparse altimeter data into the AVHRR estimates gave a modest improvement in comparisons with in situ data

Cross-Cultural Counseling: Bridge Between Desegregation and Integration. A Study Relative to Group Counseling and its Impact on Students and Faculty

For the past several years; much emphasis has been placed on open enrollment plans involving bussing that enable black and white students to attend schools together. The Laboratory School of the University of Northern Iowa in Cedar Falls has been involved in such a program since 1968. As the project developed; the potential for very serious problems relating to racial tension and student frustration became evident. To approach these problems and to promote more openness and understanding between students from different communities and differing cultural backgrounds; cross-cultural group counseling sessions were developed. The groups during the past two years have consisted of combined 7th and 8th graders and combined 9th through 12th graders. Due to administrative support; student requests; and observed behavior change; a similar grouping of students will be employed during the 1972-73 academic year. Counselor observations of the program are examined; and student and faculty questionnaires and analyses of them are also included in this paper. (Author