Discussion of ``V-Matrix Method of Solving Statistical Inference Problems" by Vlamidir Vapnik and Rauf Izmailov

We would like to begin by stating that we have not fully understood the formulation of V-matrix conceptually. However, We are fascinated by the idea of estimation of conditional probability function without assuming any probabilistic model. In this short discussion, we would like to present that the proposed constrained quadratic optimization problem for conditional probability estimation using v-matrix based method may not have a consistent solution always. We are sure that the paper will stimulate a deeper exploration of V-matrix based methods for inference in high-dimensional problems in future research.

Karakterisasi Paparan Long Term Particulate Matter di Puspiptek Serpong-Kota Tangerang Selatan

Pencemaran partikulat udara (PM10 dan PM2.5) tidak mengenal batas administrasi wilayah hal ini disebabkan bahwa pencemaran udara tidak hanya berasal dari wilayah lokal namun dapat bertransportasi dari provinsi maupun negara lain. Unsur sampel partikulat yang dikumpulkan di Serpong, Tangerang Selatan selama 24 jam periode tahun 2011 sampai dengan 2013 diidentifikasikan dengan Spekstroskopi Florensensi Sinar-X (XRF). Karekterisasi faktor dilakukan dengan menggunakan reseptor model positive matrix factorization (PMF) dan perkiraan lokasi sumber pencemar menggunakan metode Conditional Probability Function (CPF). Hasil menunjukkan rentang rata-rata konsentrasi massa PM2.5 adalah 12.63 ± 1.60 to 15.89 ± 1.70 μg/m3 sedangkan untuk PM10 berkisar 29.00 ± 3.96 to 31.04 ± 3:28 μg/m3. Multi unsur yang teridentifikasi dengan XRF adalah Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Si, Ti, V dan Zn. Karakterisasi partikulat halus (PM2.5) teridentifikasi 5 faktor yaitu industri peleburan logam Pb (9.61%), debu tanah (17%), campuran industri peleburan logam dan garam laut (13.02%), trasnportasi (44.36%) serta pembakaran biomassa (22.58%).Kata kunci : polusi udara, spektroskopi XRF, sumber pembagian, fungsi probabilitasbersyarat

Atmospheric speciated mercury concentrations on an island between China and Korea: sources and transport pathways

As a global pollutant, mercury (Hg) is of particular concern in East Asia, where anthropogenic emissions are the largest. In this study, speciated Hg concentrations were measured on Yongheung Island, the westernmost island in Korea, located between China and the Korean mainland to identify the importance of local and regional Hg sources. Various tools including correlations with other pollutants, conditional probability function, and back-trajectory-based analysis consistently indicated that Korean sources were important for gaseous oxidized mercury (GOM) whereas, for total gaseous mercury (TGM) and particulate bound mercury (PBM), regional transport was also important. A trajectory cluster based approach, considering both Hg concentration and the fraction of time each cluster was impacting the site, was developed to quantify the effect of Korean sources and out-of-Korean sources. This analysis suggests that contributions from out-of-Korean sources were similar to Korean sources for TGM whereas Korean sources contributed slightly more to the concentration variations of GOM and PBM compared to out-of-Korean sources. The ratio of GOM/PBM decreased when the site was impacted by regional transport, suggesting that this ratio may be a useful tool for identifying the relative significance of local sources vs. regional transport. The secondary formation of PBM through gas-particle partitioning with GOM was found to be important at low temperatures and high relative humidity.

Atmospheric speciated mercury concentrations on an island between China and Korea: sources and transport pathways

As a global pollutant, mercury (Hg) is of particular concern in East Asia where anthropogenic emissions are the largest. In this study, speciated Hg concentrations were measured in the western most island in Korea, located between China and the Korean mainland to identify the importance of local, regional and distant Hg sources. Various tools including correlations with other pollutants, conditional probability function, and back-trajectory based analysis consistently indicated that Korean sources were important for gaseous oxidized mercury (GOM) whereas, for total gaseous mercury (TGM) and particulate bound mercury (PBM), long-range and regional transport were also important. A trajectory cluster based approach considering both Hg concentration and the fraction of time each cluster was impacting the site was developed to quantify the effect of Korean sources and out-of-Korean source. This analysis suggests that Korean sources contributed approximately 55 % of the GOM and PBM while there were approximately equal contributions from Korean and out-of-Korean sources for the TGM measured at the site. The ratio of GOM / PBM decreased when the site was impacted by long-range transport, suggesting that this ratio may be a useful tool for identifying the relative significance of local sources vs. long-range transport. The secondary formation of PBM through gas-particle partitioning with GOM was found to be important at low temperatures and high relative humidity.

Source apportionment of PM2.5 at two receptor sites in Brisbane, Australia

Environmental contextFine particles affect air quality locally, regionally and globally. Determining the sources of fine particle is therefore critical for developing strategies to reduce their adverse effects. Advanced data analysis techniques were used to determine the sources of fine particles at two sites, providing information for future pollution reduction strategies not only at the study sites but in other areas of the world as well. AbstractIn this study, samples of particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) collected at two sites in the south-east Queensland region, a suburban (Rocklea) and a roadside site (South Brisbane), were analysed for H, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Pb and black carbon (BC). Samples were collected during 2007–10 at the Rocklea site and 2009–10 at the South Brisbane site. The receptor model Positive Matrix Factorisation was used to analyse the samples. The sources identified included secondary sulfate, motor vehicles, soil, sea salt and biomass burning. Conditional probability function analysis was used to determine the most likely directions of the sources. Future air quality control strategies may focus on the particular sources identified in the analysis.

TEMPERATURE ESTIMATION IN THE TWO-DIMENSIONAL ISING MODEL

We present two new algorithms for the estimation of the temperature from a realization of a 2-D Ising model. The methods here introduced are based in the maximization of pseudo likelihood and on the minimum mean squared error (MSE) fit of the conditional probability function. We derive the analytical expressions of these estimators and also we include computational results comparing these new techniques with the traditional method. A very good performance in terms of the average absolute error and the average standard deviation is demonstrated through simulations in a 100 × 100 lattice in the ferromagnetic and antiferromagnetic cases. Summarizing, we have provided two new useful computational tools that allow us to measure the "virtual" temperature of an Ising like system.