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Multi-Model Communication and Data Assimilation for Mitigating Model Error and Improving Forecasts

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Chinese Annals of Mathematics,Series B 2019年第5期40卷 689-720页

作者： Yian CHEN samuel N.STECHMANN Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Statistics University of ChicagoChicagoIL 60637USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Models for weather and climate prediction are complex, and each model typically has at least a small number of phenomena that are poorly represented, such as perhaps the Madden-Julian Oscillation(MJO for short) or El Nino-Southern Oscillation(ENSO for short) or sea ice. Furthermore, it is often a very challenging task to modify and improve a complex model without creating new deficiencies. On the other hand, it is sometimes possible to design a low-dimensional model for a particular phenomenon, such as the MJO or ENSO, with significant skill, although the model may not represent the dynamics of the full weather-climate system. Here a strategy is proposed to mitigate these model errors by taking advantage of each model’s strengths. The strategy involves inter-model data assimilation, during a forecast simulation, whereby models can exchange information in order to obtain more faithful representations of the full weather-climate system. As an initial investigation, the method is examined here using a simplified scenario of linear models, involving a system of stochastic partial differential equations(SPDEs for short)as an imperfect tropical climate model and stochastic differential equations(SDEs for short) as a low-dimensional model for the MJO. It is shown that the MJO prediction skill of the imperfect climate model can be enhanced to equal the predictive skill of the lowdimensional model. Such an approach could provide a route to improving global model forecasts in a minimally invasive way, with modifications to the prediction system but without modifying the complex global physical model itself.

关键词： MJO Multi-Model communication Data assimilation Kalman filter algorithm

Synthesis, molecular docking and antibacterial evaluation of 2-（ 4-（ 4-aminophenylsulfonyl）phenylam ino ）-3-（thiophen-2- ylthio）naphthalene-1,4-dione derivatives

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Frontiers of Chemical Science and Engineering 2015年第1期9卷 46-56页

作者： Palanisamy RAVICHANDIRAN Dhanaraj PREMNATH samuel VASANTHKUMA Department of Chemistry School of Science & Humanities Karunya University Coimbatore-641 114 India Department of Bioinformatics School of Biotechnology and Health sciences Karunya University Coimbatore-641 114 India

A new series of 2-（4-（4-aminophenylsulfonyl） phenylamino）-3-（thiophen-2-ylthio）naphthalene-1,4-dione derivatives （3a-3n） were synthesized and characterized by spectral techniques. To understand the interaction of binding sites with bacterial protein receptor, the docking study was performed by the GLIDE program and compound N-（4-（4-（1,4-dioxo-3-（thiophen-2-ylthio）- 1,4- dihydronaphthalen-2-ylamino）phenylsulfonyl）phenyl）-3- methylbenzamide （3b） exhibited good glide and E model scores of-5.89 and -94.90, respectively. Moreover among all the molecules studied including the standards used, namely Sparfloxacin （4.8 μg/mL） and Norfloxacin （no inhibition observed） for their antibacterial property, compound N-（4-（4-（1,4-dioxo-3-（thiophen-2-ylthio）- 1,4- dihydronaphthalen-2-ylamino）phenylsulfonyl）phenyl）-4- nitrobenzamide （3e） exhibited the lowest minimum inhibitory concentration （MIC） value of 1.3 μg/mL against Proteus vulgaris.

关键词： MIC 2-thiophene thiol water as solvent acidchlorides sulfone

Deobfuscation,unpacking,and decoding of obfuscated malicious JavaScript for machine learning models detection performance improvement

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CAAI Transactions on Intelligence Technology 2020年第3期5卷 184-192页

作者： samuel Ndichu Sangwook Kim Seiichi Ozawa Graduate School of Engineering Kobe UniversityKobe CityJapan Center for Mathematical and Data Sciences Kobe UniversityKobe CityJapan

Obfuscation is rampant in both benign and malicious JavaScript(JS)*** generates an obscure and undetectable code that hinders comprehension and ***,accurate detection of JS codes that masquerade as innocuous scripts is *** existing deobfuscation methods assume that a specific tool can recover an original JS code *** a multi-layer obfuscation,general tools realize a formatted JS code,but some sections remain *** the detection of such codes,this study performs Deobfuscation,Unpacking,and Decoding(DUD-preprocessing)by function redefinition using a Virtual Machine(VM),a JS code editor,and a python int_to_str()function to facilitate feature learning by the FastText *** learned feature vectors are passed to a classifier model that judges the maliciousness of a JS *** performance evaluation,the authors use the Hynek Petrak’s dataset for obfuscated malicious JS codes and the SRILAB dataset and the Majestic Million service top 10,000 websites for obfuscated benign JS *** then compare the performance to other models on the detection of DUD-preprocessed obfuscated malicious JS *** experimental results show that the proposed approach enhances feature learning and provides improved accuracy in the detection of obfuscated malicious JS codes.

关键词： JavaScript editor python

Kinetic Alfven Waves Excited by Cometary Newborn Ions with Large Perpendicular Energies

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Plasma Science and Technology 2011年第2期13卷 135-139页

作者： George samuel Devi E SAVITHRI Venugopal CHANDU School of Pure and Applied Physics Mahatma Gandhi University

Stability of the kinetic Alfven wave in a plasma of hydrogen, oxygen and electrons is studied. Each species is modeled by drifting ring distributions in the direction parallel to the magnetic field, while in the perpendicular direction the distribution is simulated with a loss cone type distribution obtained through the subtraction of two Maxwellian distributions with different temperatures. It is found that for frequencies ω＊〈 ωcH with ω＊ and ωcH the Doppler shifted and hydrogen ion gyro-frequencies, respectively, the growth rate of the kinetic Alfven wave increases with the increase in propagation angles and density of oxygen ions. On the other hand, for frequencies ω＊〈 ωco with ωco the oxygen ion gyro-frequency the growth rate is independent of the oxygen ion density.

关键词： kinetic Alfven wave stability multi-ion cometary plasma

Methyl acetate-methanol mixture separation by extractive distillation:Economic aspects

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 670-682页

作者： Elena Graczova Branislav Sulgan samuel Barabas Pavoi Steltenpohl Institute of Chemical and Environmental Engineering Faculty of Chemical and Food Technology Slovak University of Technology in Bratislava81237 BratislavaSlovakia

Methyl acetate is considered low toxicity volatile solvent produced either as a by-product during methanol carbonylation or via acetic acid esterification with methanol. In both cases, pure methyl acetate has to be isolated from the reaction mixture. Simulation of methyl acetate separation from its mixture with methanol by extraction distillation was carried out in ASPEN + software. In total three case studies were assumed using two different extraction solvents and two solvent regeneration strategies. In case A, novel extraction solvent 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid, was considered. Raw material separation was achieved in an extraction distillation column while the solvent regeneration was accomplished in a second distillation column in this case. In case study B, the same extraction solvent was used; however, its regeneration was carried out in a single-effect evaporator. Dimethyl sulfoxide was the second extraction solvent selected. Its use in methyl acetate-methanol separation is presented in case study C. As high purity of dimethyl sulfoxide was required for the methyl acetate-methanol azeotrope breaking, its regeneration was carried out in the second distillation column only. To simulate the ternary methyl acetate-methanol-extraction solvent mixtures separation, vapor-liquid equilibrium was predicted based on the NRTL equation. Further, unknown properties of the considered ionic liquid and variation of these properties with temperature were predicted and introduced into the ASPEN + components properties database. Based on these data, optimum operation parameters of the respective separation equipment were established. In all case studies, the same condition had to be fulfilled, namely minimum methyl acetate content in the distillate from the extraction distillation column of 99.5mol-%. Results of simulations using the respective optimum operation parameters were employed in the economic evaluation of the three separation un

关键词： methyl acetate 1-ethyl-3-methylimidazolium trifluoromethanesulfonate extraction distillation dimethyl sulfoxide economic evaluation

Thermodynamic analysis for a third grade fluid through a vertical channel with internal heat generation

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Journal of Hydrodynamics 2015年第2期27卷 264-272页

作者： ADESANYA samuel O. MAKINDE Oluwole D. Department of Mathematical Sciences Redeemer's University Faculty of Military Science Stellenbosch University

This paper makes the thermodynamic analysis in forced convective flow of a third grade fluid through a vertical channel. Due to the reactive nature of the fluid, the effect of internal heat generation is considered and assumed to be a linear function of temperature. The coupled nonlinear dimensionless ordinary differential equations governing the fluid flow are solved by using the Adomian decomposition method（ADM）. The effects of various physical parameters such as third grade material parameter, buoyancy parameter and heat generation parameter on the thermal structure of flow are presented and discussed.

关键词： energy conservation vertical channel third grade fluid internal heat generation Adomian decomposition method(ADM)

Field report:Sailing around the exhumed roots of the Mesozoic Patagonian paleo-accretionary wedge(Diego de Almagro Island,Chile)

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Geoscience Frontiers 2018年第5期9卷 1591-1594页

作者： samuel Angiboust Jesus Munoz Institut de Physique du Globe de Paris Sorbonne Paris CitéUniversity Paris DiderotCNRSF-75005ParisFrance GFZ German Research Centre for Geosciences D-14473PotsdamGermany Carrera de Geología Universidad Andres BelloSazie2119SantiagoChile

We undertook a boat expedition to explore the geological framework of a very remote, lesser-known island, in the Chilean Patagonia: the Diego de Almagro Island(latitude S51°330'). This uninhabited, ca.400 km^2 Island is one of the very rare exposures of the Mesozoic accretionary subduction complex along the Chilean margin. Unstable weather, strong winds, steep topography, and very dense vegetation make an on-land mission difficult. Careful preparation based on high-resolution satellite images is advised to optimize shore access and minimize risks of injury. Despite a relatively important degree of regional reequilibration of metamorphic assemblages due to sluggish exhumation through the forearc crust, our results have shown that the island is composed of a nappe stack of ocean-floor derived slivers of metasedimentary units that exhibit very different pressure-temperature-time paths during burial by subduction under the Chilean margin and subsequent exhumation. These rocks are witness to a complex thermal evolution of the subduction zone between Jurassic and Cretaceous times from granulite facies to blueschist facies conditions as well as multiple episodes of accretion at ca. 35 -40 km in depth for almost100 Ma over the Mesozoic era.

关键词： Patagonia Accretionary wedge Blueschists Subduction Chile

Prediction of the Cu oxidation state from EELS and XAS spectra using supervised machine learning

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npj Computational Materials 2024年第1期10卷 927-936页

作者： samuel P.Gleason Deyu Lu Jim Ciston National Center for Electron Microscopy Facility Molecular FoundryLawrence Berkeley National LaboratoryBerkeleyCAUSA Department of Chemistry University of CaliforniaBerkeleyCAUSA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNYUSA

Electron energy loss spectroscopy(EELS)and X-ray absorption spectroscopy(XAS)provide detailed information about bonding,distributions and locations of atoms,and their coordination numbers and oxidation ***,analysis of XAS/EELS data often relies on matching an unknown experimental sample to a series of simulated or experimental standard *** limits analysis throughput and the ability to extract quantitative information from a *** this work,we have trained a random forest model capable of predicting the oxidation state of copper based on its L-edge *** model attains an R2 score of 0.85 and a root mean square error of 0.24 on simulated *** has also successfully predicted experimental L-edge EELS spectra taken in thiswork and XAS spectra extracted from the *** further demonstrate the utility of this model by predicting simulated and experimental spectra ofmixed valence samples generated by this *** model can be integrated into a real-time EELS/XAS analysis pipeline on mixtures of copper-containing materials of unknown composition and oxidation *** expanding the training data,this methodology can be extended to data-driven spectral analysis of a broad range of materials.

关键词： EELS spectra analysis

A geometry-based framework for modeling the complexity of origami folding

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Theoretical & Applied Mechanics Letters 2021年第3期11卷 115-124页

作者： samuel Schulman Xin Ning Department of Aerospace Engineering The Pennsylvania State UniversityUniversity ParkPennsylvania 16802USA

This paper presents a quantitative framework to analyze the complexity of folding origami structures from flat *** efforts have realized intricate origami patterns with desired functions such as mechanical properties,packaging efficiency,and deployment ***,the complexity associated with the manufacturing or folding of origami patterns has not been *** how difficult origami structures are to make,and how much time they require to form is crucial information to determining the practical feasibility of origami designs and future applications such as robotic origami assembly in *** this work,we develop this origami complexity metric by modeling the geometric properties and crease formation of the origami structure,from which it outputs crease and pattern complexity values and a prediction of the time to complete the pattern assembly,based on the characteristics of the *** framework is experimentally validated by fabricating various Miura-ori origami paper models.

关键词： Origami folding Framework Miura-ori