Borderline Over-sampling for Imbalanced Data Classification

Traditional classification algorithms, in many times, perform poorly on imbalanced data sets in which some classes are heavily outnumbered by the remaining classes. For this kind of data, minority class instances, which are usually much more of interest, are often misclassified. The paper proposes a method to deal with them by changing class distribution through over-sampling at the borderline between the minority class and the majority class of the data set. A Support Vector Machines (SVMs) classifier then is trained to predict new unknown instances. Compared to other over-sampling methods, the proposed method focuses only on the minority class instances lying around the borderline due to the fact that this area is most crucial for establishing the decision boundary. Furthermore, new instances will be generated in such a manner that minority class area will be expanded further toward the side of the majority class at the places where there appear few majority class instances. Experimental results show that the proposed method can achieve better performance than some other over-sampling methods, especially with data sets having low degree of overlap due to its ability of expanding minority class area in such cases

The Design and Operation of The Keck Observatory Archive

The Infrared Processing and Analysis Center (IPAC) and the W. M. Keck Observatory (WMKO) operate an archive for the Keck Observatory. At the end of 2013, KOA completed the ingestion of data from all eight active observatory instruments. KOA will continue to ingest all newly obtained observations, at an anticipated volume of 4 TB per year. The data are transmitted electronically from WMKO to IPAC for storage and curation. Access to data is governed by a data use policy, and approximately two-thirds of the data in the archive are public.Comment: 12 pages, 4 figs, 4 tables. Presented at Software and Cyberinfrastructure for Astronomy III, SPIE Astronomical Telescopes + Instrumentation 2014. June 2014, Montreal, Canad

HST Imaging Polarimetry of the Gravitational Lens FSC10214+4724

We present imaging polarimetry of the extremely luminous, redshift 2.3 IRAS source FSC10214+4724. The observations were obtained with HST's Faint Object Camera in the F437M filter, which is free of strong emission lines. The 0.7 arcsec long arc is unresolved to 0.04 arcsec FWHM in the transverse direction, and has an integrated polarization of 28 +/- 3 percent, in good agreement with ground-based observations. The polarization position angle varies along the arc by up to 35 deg. The overall position angle is 62 +/- 3 deg east of north. No counterimage is detected to B = 27.5 mag ($3\sigma$), giving an observed arc to counterimage flux ratio greater than 250, considerably greater than the flux ratio of 100 measured previously in the I-band. This implies that the configuration of the object in the source plane at the B-band is different from that at I-band, and/or that the lensing galaxy is dusty.Comment: 17 pages, 3 figures. Accepted for publication in Astronomical Journal, February 199

Regional and local emissions in red river delta, Northern Vietnam

Fine (PM2.2) and coarse (PM2.2–10) particles concurrently collected in urban (Hanoi) and rural (Lucnam) areas were analyzed for ionic and elemental compositions to provide input for PMF receptor modeling of emission sources in the Red River Delta (RRD), a key economic development region in Vietnam. Long-range transport (LRT) aerosol, coal fly ash from major coal-fired plants in RRD, and marine aerosols are regional sources, which explain the minor variability of the mass concentrations of fine particles across the region. Local sources include soil/resuspended road dust, local coal fly ash, and biomass burning. Soil/resuspended road dust is the largest source component of coarse particles at the two sites. It is more abundant in Hanoi than in Lucnam reflecting the urban–rural contrast in traffic and construction works. Receptor models reveal the incorporation of secondary sulfate, nitrate, and ammonium into the various primary particles, i.e., soot, minerals, soil organic matter, and sea salt. Soot particles from LRT carry the largest amounts of sulfate and ammonium mass concentrations measured at the two sites. Based on receptor models, the yields and possible chemical forms of secondary sulfate, nitrate, and ammonium in different types of primary particles can be inferred

VARIANCE INFLATION FACTORS IN REGRESSION MODELS WITH DUMMY VARIABLES

Variance Inflation Factors (VIFs) are used to detect collinearity among predictors in regression models. Textbook explanation of collinearity and diagnostics such as VIFs have focused on numeric predictors as being co-linear or co-planar , with little attention paid to VIFs when a dummy variable is included in the model. This work was motivated by two regression models with high VIFs, where standard\u27 interpretations of causes of collinearity made no sense. The first was an alfalfa-breeding model with two numeric predictors and two dummy variables. The second was an economic model with one numeric predictor, one dummy and the numeric x dummy cross-product. This paper gives formulas for VIFs for several regression models with a dummy variable which indicate that these VIFs are functions of the numeric predictors\u27 means, sums of squares and sample sizes within the two dummy groups. The economic regression model is also presented to illustrate how high VIFs occurred in this data. Researchers should be cautious in using high VIFs as a reason for deleting predictors in general but especially if dummy variables are involved. It is recommended that collinearity diagnostics be applied to the numeric predictors first to check for collinearity without the influence of any dummies, then add dummy variables in one at a time to see their effect on VIFs

Qualite et vitesse de decomposition des litieres des principaux arbustes natifs de la savane humide au centre de la Cote d’Ivoire

Cette étude a été conduite en zone de savane humide de Côte d’Ivoire pour évaluer la qualité et la vitesse de décomposition des litières de feuilles de trois espèces d’arbustes dominantes: Crossopteryx febrifuga, Terminalia schimperiana et Piliostigma thonningii et la contribution des termites dans ce processus. La vitesse de décomposition a été suivie pendant six mois dans des sachets (Litterbags) puis le coefficient de décomposition k a été déterminé. La contribution des termites a été estimée à travers la quantité de sol « termitique » déposée sur les sachets. Les résultats montrent que les teneurs des litières en C, N, K et Mg étaient plus élevés avec C. febrifuga qu’avec P. thonningii et T. schimperiana respectivement. Le rapport N/P suivait exactement la même tendance. La teneur en P n’a pas varié significativement avec les espèces. Les rapports C/N et C/P n’ont pas non plus varié significativement. La concentration de Ca des litières était plus élevée avec P. thonningii. La densité surfacique des litières (caractéristique physique) était plus élevée avec P. thonningii qu’avec les autres espèces. La décomposition des litières de T. schimperiana (0,64 mois-1) était plus rapide que celles de C. febribuga (0,52 mois-1) et de P. thonningii (0,39 mois-1). L’activité des termites était plus importante sous les litières les plus denses (P. thonningii). L’espèce C. febrifuga est apparue comme ayant le meilleur potentiel d’amélioration de la fertilité du sol.   English title: Quality and decomposition rate of native shrub species’ leaf litters in a wet savanna in central Côte d’Ivoire This study was conducted in Central Côte d’Ivoire, aimed to assess the quality and rate of decomposition of the dominant native shrub species’ leaf litters, namely Crossopteryx febrifuga, Terminalia schimperiana and Piliostigma thonningii and the termite’s contribution in this process. Investigations took place in the Lamto Natural Reserve, including five replicate trees per species. Leaf litters were left to decompose in litterbags for six months and then, the decomposition coefficient (k) was determined. The termites’ contribution to decomposition was estimated by the amount of soil they deposited on the litterbags. Results showed that higher leaf litter C, N, K and Mg concentrations were associated with C. febrifuga compared to P. thonningii and T. schimperiana, respectively. The N/P ratio followed the same order. Litter P, C/N and C/P ratios did not varied across species. Higher litter Ca was observed with P. thonningii. Litter surface area was higher with P. thonningii compared to the other two species while decomposition was faster with T. schimperiana (k = 0.64 month-1) followed by C. febribuga (k = 0.52 month-1) and P. thonningii (0.39 months-1). The contribution of the termites to decomposition were found to be greater on high surface area-leaf litters, supposedly more ligneous (P. thonningii). These results suggest that C. febrifuga holds a greater ability to improve soil fertility

Polarized Narrow-Line Emission from the Nucleus of NGC 4258

The detection of polarized continuum and line emission from the nucleus of NGC 4258 by Wilkes et al. (1995) provides an intriguing application of the unified model of Seyfert nuclei to a galaxy in which there is known to be an edge-on, rotating disk of molecular gas surrounding the nucleus. Unlike most Seyfert nuclei, however, NGC 4258 has strongly polarized narrow emission lines. To further investigate the origin of the polarized emission, we have obtained spectropolarimetric observations of the NGC 4258 nucleus at the Keck-II telescope. The narrow-line polarizations range from 1.0% for [S II] 6716 to 13.9% for the [O II] 7319,7331 blend, and the position angle of polarization is oriented nearly parallel to the projected plane of the masing disk. A correlation between critical density and degree of polarization is detected for the forbidden lines, indicating that the polarized emission arises from relatively dense (n_e > 10^4 cm^-3) gas. An archival Hubble Space Telescope narrow-band [O III] image shows that the narrow-line region has a compact, nearly unresolved core, implying a FWHM size of <2.5 pc. We discuss the possibility that the polarized emission might arise from the accretion disk itself and become polarized by scattering within the disk atmosphere. A more likely scenario is an obscuring torus or strongly warped disk surrounding the inner portion of a narrow-line region which is strongly stratified in density. The compact size of the narrow-line region implies that the obscuring structure must be smaller than ~2.5 pc in diameter.Comment: To appear in the Astronomical Journal. 13 pages, including 1 table and 4 figures. Uses emulateapj.st

Sustainable Farming Systems in the Sub-Sahelian Zone of Burkina Faso : Key Factors

Rapid population growth and climatic change threatens the sustainability of natural resources. Farming practices can mitigate environmental change and degradation. The aim of this research conducted in Yatenga region was to describe and to analyse manure practices management. In 2005, a survey was carried out to assess the evolution of farming practices. A survey was initially conducted with a sample of 44 farmers, selected randomly in the three neighbouring villages. Subsequently, 18 farms were selected for in-depth interviews. The grain yield was measured and the different practices of soil and water conservation developed by farmers were compared. According to the enquiries, two practices, called “zaï” and “djengo”, were largely used in cereals production. The “zaï” practice, known as a traditional technique for restoration of degraded soil, is characterized by the capture of runoff by micro-watersheds and a localized organic matter supply at the soil-plant system scale. The “djengo” practice is based on the same principle of the “zaï” practice but was applied on the sandy soil as traditionally “zaï” concerned the degraded and crusty soils. The two practices could increase grain crop production but moreover could limit the risk of crops failure. In addition, our observations also showed that frequent tree regenerations occurred in plots and watersheds where “zaï” or “djengo” practices were used. This study highlights the necessity of better controlling soil, water and organic matter to improve agrosystem sustainability in sub Saharan Africa.Rapid population growth and climatic change threatens the sustainability of natural resources. Farming practices can mitigate environmental change and degradation. The aim of this research conducted in Yatenga region was to describe and to analyse manure practices management. In 2005, a survey was carried out to assess the evolution of farming practices. A survey was initially conducted with a sample of 44 farmers, selected randomly in the three neighbouring villages. Subsequently, 18 farms were selected for in-depth interviews. The grain yield was measured and the different practices of soil and water conservation developed by farmers were compared. According to the enquiries, two practices, called “zaï” and “djengo”, were largely used in cereals production. The “zaï” practice, known as a traditional technique for restoration of degraded soil, is characterized by the capture of runoff by micro-watersheds and a localized organic matter supply at the soil-plant system scale. The “djengo” practice is based on the same principle of the “zaï” practice but was applied on the sandy soil as traditionally “zaï” concerned the degraded and crusty soils. The two practices could increase grain crop production but moreover could limit the risk of crops failure. In addition, our observations also showed that frequent tree regenerations occurred in plots and watersheds where “zaï” or “djengo” practices were used. This study highlights the necessity of better controlling soil, water and organic matter to improve agrosystem sustainability in sub Saharan Africa