General regularization in covariate shift adaptation

Sample reweighting is one of the most widely used methods for correcting the error of least squares learning algorithms in reproducing kernel Hilbert spaces (RKHS), that is caused by future data distributions that are different from the training data distribution. In practical situations, the sample weights are determined by values of the estimated Radon-Nikod\'ym derivative, of the future data distribution w.r.t.~the training data distribution. In this work, we review known error bounds for reweighted kernel regression in RKHS and obtain, by combination, novel results. We show under weak smoothness conditions, that the amount of samples, needed to achieve the same order of accuracy as in the standard supervised learning without differences in data distributions, is smaller than proven by state-of-the-art analyses

On regularized Radon-Nikodym differentiation

We discuss the problem of estimating Radon-Nikodym derivatives. This problem appears in various applications, such as covariate shift adaptation, likelihood-ratio testing, mutual information estimation, and conditional probability estimation. To address the above problem, we employ the general regularization scheme in reproducing kernel Hilbert spaces. The convergence rate of the corresponding regularized algorithm is established by taking into account both the smoothness of the derivative and the capacity of the space in which it is estimated. This is done in terms of general source conditions and the regularized Christoffel functions. We also find that the reconstruction of Radon-Nikodym derivatives at any particular point can be done with high order of accuracy. Our theoretical results are illustrated by numerical simulations.Comment: arXiv admin note: text overlap with arXiv:2307.1150

One-pot preparation of alumina-modified polysulfone-graphene oxide nanocomposite membrane for separation of emulsion-oil from wastewater

In recent years, polysulfone-based nanocomposite membranes have been widely used for contaminated water treatment because they comprise properties such as high thermal stability and chemical resistance. In this study, a polysulfone (PSf) nanocomposite membrane was fabricated using the wet-phase inversion method with the fusion of graphene oxide (GO) and alumina (Al2O3) nanoparticles. We also showed that GO-Al2O3 nanoparticles were synthesised successfully by using a one-pot hydrothermal method. The nanocomposite membranes were characterised by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherms, energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water contact angle. The loading of GO and Al2O3 was investigated to improve the hydrophilic and oil rejection of the matrix membrane. It was shown that by using 1.5 wt.% GO-Al2O3 loaded in polysulfone, ~74% volume of oil was separated from the oil/water emulsion at 0.87 bar and 30 min. This figure was higher than that of the process using the unmodified membrane (PSf/GO) at the same conditions, in which only ~60% volume of oil was separated. The pH, oil/water emulsion concentration, separation time, and irreversible fouling coefficient (FRw) were also investigated. The obtained results suggested that the GO-Al2O3 nanoparticles loaded in the polysulfone membrane might have potential use in oily wastewater treatment applications

Research of Regenerative Braking Strategy for Electric Vehicles

In the context of global energy instability caused by the transformation of global demand for energy and energy resources, one of the most important areas in the automotive industry is the development of electric vehicles. Serial production of high-tech electric vehicles with a long range contributes to the stabilization of the energy market and the sustainable development of the whole fuel-energy sector. To evaluate the possibility of optimizing the electric vehicles energy consumption, various regenerative braking strategies are discussed in the article based on the Nissan Leaf electric vehicle, which simulation model includes submodules of the traction electric motor, hybrid braking system, traction rechargeable battery and tires. In order to test the adequacy of the simulation model to reproduce the relationship between the operating parameters of electric vehicles various systems and evaluate their ability to regenerate energy during braking the simulation results were compared with the actual experimental data published by the Lab Avt research laboratory (USA). The relative error of the mathematical modeling results of the braking energy regeneration processes is 4.5 %, which indicates the adequacy of the electric vehicle simulation model and the possibility of its using as a base for research and comparison of the energy efficiency of various regenerative braking strategies. As the results of experiments have shown, the usage of the proposed control strategy of the regenerative braking maximum force allows increasing 2.14 times the energy recharging traffic to the battery as compared with the basic control strategy of fixed coefficient braking forces distribution with an increase in braking distance by 10 m. An alternative control strategy of regenerative braking optimal efficiency as compared to the basic control strategy provides a reduction in braking distance by 13.2 % at increasing by 84.4 % the amount of energy generated by the electric motor for recharging the batteries. The carried out investigations confirm the available significant potential for improving the efficiency of the electric vehicles usage by developing the control strategy and algorithms of the braking energy regeneration

Исследование стратегии рекуперативного торможения электромобилей

In the context of global energy instability caused by the transformation of global demand for energy and energy resources, one of the most important areas in the automotive industry is the development of electric vehicles. Serial production of high-tech electric vehicles with a long range contributes to the stabilization of the energy market and the sustainable development of the whole fuel-energy sector. To evaluate the possibility of optimizing the electric vehicles energy consumption, various regenerative braking strategies are discussed in the article based on the Nissan Leaf electric vehicle, which simulation model includes submodules of the traction electric motor, hybrid braking system, traction rechargeable battery and tires. In order to test the adequacy of the simulation model to reproduce the relationship between the operating parameters of electric vehicles various systems and evaluate their ability to regenerate energy during braking the simulation results were compared with the actual experimental data published by the Lab Avt research laboratory (USA). The relative error of the mathematical modeling results of the braking energy regeneration processes is 4.5 %, which indicates the adequacy of the electric vehicle simulation model and the possibility of its using as a base for research and comparison of the energy efficiency of various regenerative braking strategies. As the results of experiments have shown, the usage of the proposed control strategy of the regenerative braking maximum force allows increasing 2.14 times the energy recharging traffic to the battery as compared with the basic control strategy of fixed coefficient braking forces distribution with an increase in braking distance by 10 m. An alternative control strategy of regenerative braking optimal efficiency as compared to the basic control strategy provides a reduction in braking distance by 13.2 % at increasing by 84.4 % the amount of energy generated by the electric motor for recharging the batteries. The carried out investigations confirm the available significant potential for improving the efficiency of the electric vehicles usage by developing the control strategy and algorithms of the braking energy regeneration.В условиях энергетической нестабильности, вызванной трансформацией глобального спроса на энергию и энергоресурсы, одним из важнейших направлений в автомобилестроении является разработка транспортных средств на электрической тяге. Серийное производство высокотехнологичных электромобилей с большим запасом хода способствует стабилизации рынка энергоресурсов и устойчивому развитию всего топливно-энергетического сектора. Для оценки возможности оптимизации энергопотребления электромобилей в статье рассматриваются различные стратегии рекуперативного торможения на базе имитационной модели электромобиля Nissan Leaf, включающей субмодули тягового электродвигателя, гибридной тормозной системы, тяговой аккумуляторной батареи и шин. Результаты моделирования сопоставлялись с экспериментальными данными научно-исследовательской лаборатории Lab Avt (США), опубликованными для проверки адекватности имитационных моделей, воспроизводящих взаимосвязь между рабочими параметрами различных систем электромобиля и оценивающих их способность регенерировать энергию при торможении. Относительная погрешность результатов математического моделирования процессов рекуперации энергии составляет 4,5 %, что свидетельствует об адекватности имитационной модели электромобиля и возможности ее использования в качестве базовой для исследований и сопоставления энергоэффективности различных стратегий рекуперативного торможения. Как показали результаты экспериментов, использование предлагаемой стратегии управления максимальной силой рекуперативного торможения позволяет увеличить трафик энергии подзарядки в 2,14 раза по сравнению с базовой стратегией управления на основе фиксированного коэффициента распределения тормозных усилий по осям транспортного средства при увеличении тормозного пути на 10 м. Альтернативная стратегия управления оптимальной эффективностью рекуперативного торможения обеспечивает по сравнению с базовой стратегией уменьшение тормозного пути на 13,2 % при одновременном увеличении на 84,4 % количества вырабатываемой электродвигателем энергии для подзарядки тяговых аккумуляторных батарей. Проведенные исследования подтверждают имеющийся потенциал по повышению эффективности использования электромобилей за счет совершенствования стратегии и алгоритмов управления рекуперацией энергии торможения

Algorithm and program for earthquake prediction based on the geological, geophysical, geomorphological and seismic data

By applying an improved  method of the Earth's crust classification, we develop an algorithm and build an earthquake prediction program using a combination of geological, geophysical, geomorphological and seismic data.This program includes a system of multiple windows with different functions, which can divide fault zones into the different segments by the maximum magnitude values Mmax. Using the constructed program, we carried out an earthquake prediction test for the Northwest Vietnam by a combination of geological, geophysical, geomorphological and seismic data. According to the received results, zoning maps of maximum earthquake prediction for the researched region has been established. The results show that the   areas, capable of generating earthquakes with Mmax = 6.5 - 6.8  are primarily concentrated along some major fault zones such as Lai Chau-Dien Bien, Son La, Song Ma, Song Da, Tuan Giao or near the intersection of these fault zones. The received results show a good accordance with the actual seismotectonic characteristics of the researched region.References Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La - Bac Yen fault zone. Journal of Sciences of the Earth 35, 53-49.Cao Dinh Trieu, 1999. Probable approach for long-term earthquake prediction in Vietnam based on the regulation of epicentral distribution. Journal of Geology, Series A (251), 14-21, Hanoi (in Vietnamese).Cao Dinh Trieu, Nguyen Huu Tuyen, Thai Anh Tuan, 2006. The correlation between the structure of the Earth’s crust and seismic activities in the Northwest region of Vietnam”. Journal of Sciences of the Earth, 28, 155-164, Hanoi (in Vietnamese).Cao Dinh Trieu, Ngo Thi Lu, Cao Xuan Bach et al., 2007. Prediction of maximum earthquake occurrence in Vietnam on the basis of crustal characteristics”. Proceedings of the 5th Vietnam’s Scientific Conference on Geophysics, 159-171, Science and Technics Publishing House, Hanoi (in Vietnamese).Dang Thanh Hai, Nguyen Duc Vinh, Cao Dinh Trieu, 2002. Long-term earthquake prediction in Lai Chau-Dien Bien region on the basis of time - magnitude model. Journal of Science and Technology, 40(4), 45-53, Hanoi (in Vietnamese).Dang Thanh Hai, 2003. Study on deep structures of the Earth’s crust and seismotectonic zoning in Northern Vietnam. Physics Ph.D. Thesis, 170p, Hanoi (in Vietnamese).Grishin A.P., 2001. The statistical model for predicting the occurrence time and magnitude of the earthquake”. Journal of Volcanology and Seismology (4), 60-65, Russian Academy of Sciences, Moscow. (in Russian).Grishin A.P., N.V. Kondoskaya, L.E. Levin, L.N. Solodinov, A.L. Petrov, O.M. Petrov, 2001. “Experiment of statistical prediction in Kaspi region (occurrence time, epicenter coordinate and magnitude value of the earthquake). Geophysics in the 21th century, The 3rd Collection of Reading Materials on Geophysics, Scientific World, 149-156.Gubin I.E., 1950. The method of seismotectonic zoning. The projects of The Geophysical Center, Russian Academy of Sciences, 13.Gumbel E.J., 1958. Statistics of Extremes”. Columbia Univ. Press.Gutenberg B. and G.F. Richter, 1954. Seismicity of the Earth and associated phenomena. Princeton Univ. Press.Ngo Thi Lu, Tran Viet Phuong, 2012. About the approach to building algorithms and processes to predict earthquakes by statistical model. Journal of Sciences of the Earth, 34(4), 535-541.Ngo Thi Lu, Tran Viet Phuong, 2013. Building a new algorithm of the program for separation of forshock and aftershock groups from earthquake catalog to ensure the independence of the events. Journal of Marine Science and Technology. 3A(13), 79-85.Ngo Thi Lu (Project manager), 2011. Assessment of the seismic potential in Vietnam based on a combination of geological, geophysical and seismic data”. The international scientific cooperation between Vietnam Academy of Science and Technology and Russian Academy of Sciences under the state-level protocol (2008-2010), Final Report, 163p, Hanoi (in Vietnamese).Ngo Thi Lu (Project manager), 2013. Establishment of experimental program for short-term earthquake prediction based on the statistical model combined with tectonophysics in Vietnam and adjacent regions. The independent project of Vietnam Academy of Science and Technology, Code VAST.DL.09/11-12, 125p, Hanoi (in Vietnamese).Nguyen Hong Phuong, 1991. Probabilistic assessment of earthquake hazard in Vietnam based on seismotectonic regionalization. Tecronophysics, 198, 81-93.Nguyen Hong Phuong, 1997. Evaluation of the maximum earthquake for seismic source zones in Vietnam by a combination of probability methods. The scientific works on geology and marine geophysics (3), 48-65, Science and Technics Publishing House, Hanoi (in Vietnamese).Nguyen Hong Phuong, 2001. Probabilistic Seismic Hazard Assessment Along the Southeastern Coast of Vietnam, Natural Hazards 24, 53-74.Nguyen Hong Phuong, Pham The Truyen, 2014. Probabilistic Seismic Hazard Assessment for the South Central Vietnam. Vietnam Journal of Earth Sciences 36, 451-461.Nguyen Dinh Xuyen (Project manager), Nguyen Ngoc Thuy et al., 1996. Database of earthquake mitigation measures in Vietnam. The final report of state-level independent project, Code KT-DL 92-07, 3 volumes, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, 2002. Earthquake and earthquake hazard level. Internal document, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, Pham Dinh Nguyen, Pham Quang Hung, Nguyen Anh Duong, 2003. Experiment of long-term earthquake prediction based on the mechanism of foreshock activities. Journal of Sciences of the Earth, 25(3), 193-200, Hanoi (in Vietnamese).Phan Trong Trinh, Ngo Van Liem, Nguyen Van Huong, Hoang Quang Vinh, Bui Van Thom, Bui Thi Thao, Mai Thanh Tan, Nguyen Hoang, 2012. Late Quaternary tectonics and seismotectonics along the Red River fault zone, North Vietnam. Earth-Science Reviews 114(3), 224-235.Phan Trong Trinh , Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. Active fault segmentation and seismic hazard in Hoa-Binh reservoir, Vietnam. Cent. Eur. J. Geosci. 5(2), 223-235.Pham Van Thuc and Kijko, A., 1985. Estimation of maximum magnitude and seismic hazard in Southeast Asia and Vietnam. Acta Geophys. Pol., XXX111 (4), 377-387.Pham Van Thuc, 2007. Seismology and earthquake in Vietnam. The monographs on natural resources and environment in Vietnam, Publishing House for Science and Technology, Vietnam Academy of Science and Technology, 378p (in Vietnamese).Reisner G.I., L.I. Ioganson, M.G. Reisner, Iu.E. Baranov, 1993. Characteristic classification of the Earth’s crust and the modern geological process. Publishing House of Russian Academy of Sciences, Moscow, 210p (in Russian).Reisner G.I., L.I. Ioganson, 1996. The Extraregional Seismotectonic Method for the Assessment of Seismic Potential. Natural Hazards 14, 3-10 (Kluwer Academic Publishers, printed in the Netherlands).Tran Thi My Thanh, 2002. Assessment of seismic hazard in Vietnam and adjacent regions. Physics Ph.D. Thesis, 161 pages, Hanoi (in Vietnamese).Vu Thi Hoan, Ngo Thi Lu, M.V. Rodkin, Tran Viet Phuong, 2014. Application of the generalized extreme value distribution to study the seismicity of the Southeast Asian. Journal of Geology. Series A, 341-345. Hanoi. 

Effect of the supporting electrolyte anion on the thickness of PSS/PAH multilayer films and on their permeability to an electroactive probe.

Quartz crystal microbalance and cyclic voltammetry are used to investigate the influence of the supporting salt of polyelectrolyte solutions on the buildup and the structure of PSS/PAH polyelectrolyte multilayers (PSS: poly(4-styrene sulfonate); PAH: poly(allylamine hydrochloride)). This film constitutes a model polyelectrolyte multilayer system. The supporting electrolytes were sodium salts where the nature of the anion was changed by following the Hofmeister series from cosmotropic to chaotropic anions (F-, Cl-, NO3-, ClO4-). For all the investigated anions, the film thickness increases linearly with the number of deposition steps.Wefind that chaotropic anions lead to larger thickness increments per bilayer during the film buildup than cosmotropic ones, confirming results found on PSS/PDADMA multilayers (PDADMA:poly(diallyldimethylammonium)). Films constituted by more than nine PSS/PAH bilayers are still permeable to hexacyanoferrate(II) ions, Fe(CN)(6)4-, whatever the nature of the supporting salt anion. On the other hand, these films are impermeable to ruthenium(II) hexamine ions, Ru(NH3)(6)2+, after the third PAH layer in the presence of NaF, NaCl, or NaNO3. These results are explained by the presence of an excess of positive charges in the film, which leads to a positive Donnan potential. We find that this potential is more positive when more chaotropic anions are used during the film buildup. We also find that a film constructed in the presence of chaotropic anions swells and becomes more permeable to Fe(CN)(6)4- ions when the film is brought into contact with a solution containing more cosmotropic anions. All our experimental findings can be explained by a strong interaction between chaotropic anions with the NH3+groups of PAH that is equivalent, as far as the multilayer buildup and electrochemical response is concerned, to a deprotonation of PAH as it is observed when the film is constructed at a higher pH. We thus arrive to a coherent explanation of the effect of the nature of the anions of the supporting electrolyte on the polyelectrolyte multilayer. We also find that great care must be taken when investigating polyelectrolyte multilayer films by electrochemical probing because electrochemical reactions involving the probes can appreciably modify the multilayer structure.journal articleresearch support, non-u.s. gov't2009 Feb 17importe

Symbiotic organs shaped by distinct modes of genome evolution in cephalopods.

Microbes have been critical drivers of evolutionary innovation in animals. To understand the processes that influence the origin of specialized symbiotic organs, we report the sequencing and analysis of the genome of Euprymna scolopes, a model cephalopod with richly characterized host-microbe interactions. We identified large-scale genomic reorganization shared between E. scolopes and Octopus bimaculoides and posit that this reorganization has contributed to the evolution of cephalopod complexity. To reveal genomic signatures of host-symbiont interactions, we focused on two specialized organs of E. scolopes: the light organ, which harbors a monoculture of Vibrio fischeri, and the accessory nidamental gland (ANG), a reproductive organ containing a bacterial consortium. Our findings suggest that the two symbiotic organs within E. scolopes originated by different evolutionary mechanisms. Transcripts expressed in these microbe-associated tissues displayed their own unique signatures in both coding sequences and the surrounding regulatory regions. Compared with other tissues, the light organ showed an abundance of genes associated with immunity and mediating light, whereas the ANG was enriched in orphan genes known only from E. scolopes Together, these analyses provide evidence for different patterns of genomic evolution of symbiotic organs within a single host

A Retrospective Analysis of the Haemodynamic and Metabolic Effects of Fluid Resuscitation in Vietnamese Adults with Severe Falciparum Malaria

BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs