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Few-Shot Learning Enables Population-Scale Analysis of Leaf Traits in Populus trichocarpa

Plant Phenomics 2023年第3期5卷 581-597页

作者： John Lagergren Mirko Pavicic hari b.chhetri Larry M.York Doug Hyatt David Kainer Erica M.Rutter Kevin Flores Jack bailey-bale Marie Klein Gail Taylor Daniel Jacobson Jared Streich biosciences Division Oak Ridge National LaboratoryOak RidgeTNUSA Department of Applied Mathematics University of CaliforniaMercedCAUSA Department of Mathematics North Carolina State UniversityRaleighNCUSA Department of Plant Sciences University of CaliforniaDavisCAUSA

Plant phenotyping is typically a time-consuming and expensive endeavor,requiring large groups of researchers to meticulously measure biologically relevant plant traits,and is the main bottleneck in understanding plant adaptation and the genetic architecture underlying complex traits at population *** this work,we address these challenges by leveraging few-shot learning with convolutional neural networks to segment the leaf body and visible venation of 2,906 Populus trichocarpa leaf images obtained in the *** contrast to previous methods,our approach(a)does not require experimental or image preprocessing,(b)uses the raw RGb images at full resolution,and(c)requires very few samples for training(e.g.,just 8 images for vein segmentation).Traits relating to leaf morphology and vein topology are extracted from the resulting segmentations using traditional open-source image-processing tools,validated using real-world physical measurements,and used to conduct a genome-wide association study to identify genes controlling the *** this way,the current work is designed to provide the plant phenotyping community with(a)methods for fast and accurate image-based feature extraction that require minimal training data and(b)a new population-scale dataset,including 68 different leaf phenotypes,for domain scientists and machine learning *** of the few-shot learning code,data,and results are made publicly available.

关键词： networks neural image

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Predicting upslope expansion of sub-alpine forest in the Makalu barun National Park, Eastern Nepal, with a hybrid cartographic model

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Journal of Forestry Research 2018年第1期29卷 129-137页

作者： Parveen Kumar chhetri Department of Geography Texas A&M UniversityCollege Station

The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the *** prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest *** inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.

关键词： Climate change Forest line Forest line advance Hybrid cartographic model Makalu barun National Park

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How does the stand structure of treeline-forming species shape the treeline ecotone in different regions of the Nepal Himalayas?

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Journal of Mountain Science 2020年第10期17卷 2354-2368页

作者： Parveen K.chhetri Raju bISTA Krishna b.SHRESTHA Department of Earth Science and Geography California State UniversityDominguez HillsCarsonCalifornia90747USA Department of biological Sciences University of BergenPO Box 7803N-5020BergenNorway

Stand structure dynamics are considered as major happenings in any forest as a response to environmental ***,this important topic is underrepresented in the treeline studies in the Nepal *** aimed to investigate site-as well as species-specific changes in morphometric features(basal diameter,crown cover,density,and height)along the elevational gradient across treeline ecotones in response to recent environmental *** stand structure characteristics of Abies spectabilis,Pinus wallichiana,and betula utilis across the treeline ecotone of three study sites in Eastern(barun),Central(Manang),and Western(Dhorpatan)Nepal were analyzed to elucidate structural ***,eight transects(20 m×(60–250 m))across the treeline ecotone were *** of all life forms,trees(>2 m),saplings(0.5–2 m),and seedlings(basal area increment was higher in barun,but the Manang treeline,despite profound regeneration in recent years,had a low annual basal area ***,the altitudinal distribution of age and morphometry were not consistent among those ***,intra-specific competition was not *** site-specific stand structure dynamics explain why treelines do not respond uniformly to increasing *** invokes,in further studies,the incorporation of the tree’s morphometric adaptation traits,phenotypic plasticity,and interactions between species genotype and the environment.

关键词： Climate change Morphometry Nepal Himalayas Stand structure Treeline Tree-rings

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Novel predictive tool for accurate estimation of packed column size

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Journal of Natural Gas Chemistry 2010年第2期19卷 146-150页

作者： Alireza bahadori hari b.Vuthaluru Department of Chemical Engineering Curtin University of TechnologyGPO Box U1987PerthWA 6845Australia

Traditionally the majority of fractionation columns in natural gas processing plants were equipped with *** an option to trayed columns is to use *** columns offer a larger surface area per unit volume for mass transfer and the continuous gas to liquid contact throughout the column rather than at specific levels （such as in tray columns）.For process design purposes,it is essential to estimate the pressure drop for enabling the proper operation of packed *** this study,a simple generalized pressure drop correlation （GPDC） which is easier than existing approaches requiring more complicated and longer computations is developed for sizing randomly packed fractionation columns for pressure drops up to 150 mm water per meter of *** correlation can be used to estimate pressure drop for a given loading and column ***,for a given pressure drop the diameter can be *** predictions from the proposed correlation have been compared with reported data and found good agreement with average absolute deviation hovering around 4.9%.The proposed predictive tool is superior owing to its accuracy and clear numerical background,wherein the relevant coefficients can be retuned quickly if new and more accurate data are available in the *** proposed simple-to-use approach can be of immense practical value for the engineers and scientists to have a quick check on the pressure drop in packed columns for a given loading and column *** particular,gas engineers would find the proposed approach can be used very friendly involving no complex expressions with transparent and easy-to-handle calculation steps.

关键词： packed columns packing pressure drop flooding design principles

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Modeling Spatial–Temporal Dynamics of Urban Residential Fire Risk Using a Markov Chain Technique

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International Journal of Disaster Risk Science 2019年第1期10卷 57-73页

作者： Rifan Ardianto Prem chhetri School of business IT and Logistics RMIT (Royal Melbourne Institute of Technology) University

This article applies a Markov chain method to compute the probability of residential fire occurrence based on past fire history. Fitted with the fire incidence data gathered over a period of 10 years in Melbourne, Australia,the spatially-integrated fire risk model predicts the likely occurrence of fire incidents using space and time as key model parameters. The mapped probabilities of fire occurrence across Melbourne show a city-centric spatial pattern where inner-city areas are relatively more vulnerable to a fire than outer suburbia. Fire risk reduces in a neighborhood when there is at least one fire in the last1 month. The results show that the time threshold of reduced fire risk after the fire occurrence is about 2 *** risk increases when there is no fire in the last 1 month within the third-order neighborhood(within 5 km). A fire that occurs within this distance range, however, has no significant effect on reducing fire risk level within the neighborhood. The spatial–temporal dependencies of fire risk provide new empirical evidence useful for fire agencies to effectively plan and implement geo-targeted fire risk interventions and education programs to mitigate potential fire risk in areas where and when they are most needed.

关键词： Australia Markov chain Melbourne Residential fire risk Spatial– temporal analysis

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Analyzing solubility of acid gas and light alkanes in triethylene glycol

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Journal of Natural Gas Chemistry 2008年第1期17卷 51-58页

作者： Alireza bahadori hari b.Vuthaluru Saeid Mokhatab Department of Chemical Engineering Curtin University of TechnologyGPO Box 1987PerthWA 6845Australia Process Technology Manager Tehran Raymand Consulting EngineersTehranIran

Physical solvents such as ethylene glycol （EG）, diethylene glycol （DEG）, and triethylene glycol （TEG） are commonly used in wet gas dehydration processes with TEG being the most popular due to ease of regeneration and low solvent losses. Unfortunately, TEG absorbs significantly more hydrocarbons and acid gases than EG or DEG. Quantifying this amount of absorption is therefore critical in order to minimize hydrocarbon losses or to optimize hydrocarbon recovery depending on the objective of the process. In this article, a new correlation that fully covers the operating ranges of TEG dehydration units is developed in order to determine the solubility of light alkanes and acid gases in TEG solvent. The influence of several parameters on hydrocarbon and acid gas solubility including temperature, pressure, and solvent content is also examined.

关键词： solubility triethylene glycol acid gas hydrocarbon gas dehydration

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Topography and human disturbances are major controlling factors in treeline pattern at barun and Manang area in the Nepal Himalaya

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Journal of Mountain Science 2017年第1期14卷 119-127页

作者： Parveen K.chhetri Krishna b.SHRESTHA David M.CAIRNS Department of Geography Texas A&M University College Station TX 77840 USA Uib Global Jekteviksbakken 31 PO Box 7800 5020 Bergen Norway

The alpine treeline ecotone is an important component of mountain ecosystems of the Nepal Himalaya; it plays a vital role in the livelihood of indigenous people,and provides ecosystem services. However,the region faces a problem of paucity of data on treeline characteristics at the regional and landscape scales. Therefore,we used Remote Sensing(RS),and Geographic Information Science(GIS) approaches to investigate cross-scale interactions in the treeline ecotone. Additionally,European Space Agency land cover map,International Center for Integrated Mountain Development(ICIMOD) land cover map,ecological map of Nepal,and United States Geological Survey Shuttle Radar Topography Mission-Digital Elevation Model were used to analyze treeline pattern at the regional scale. Digital Globe high-resolution satellite imagery of barun(eastern Nepal) and Manang(central Nepal) were used to study treeline patterns at the landscape scale. Treeline elevation ranges from 3300-4300 m above sea level. Abies spectabilis,betula utilis,and Pinus wallichiana are the main treeline-forming species in the Nepal Himalaya. There is an east to west treeline elevationgradient at the regional scale. No slope exposure is observed at the regional scale; however,at the landscape scale,slope exposure is present only in a disturbed area(Manang). Topography and human disturbance are the main treeline controlling factor in barun and Manang respectively.

关键词： Alpine Treeline Mountain ecosystem Himalaya Remote Sensing(RS) Geographic Information Science(GIS)

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Remote sensing and geographic information systems techniques in studies on treeline ecotone dynamics

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Journal of Forestry Research 2019年第5期30卷 1543-1553页

作者： Parveen K.chhetri Eric Thai Department of Earth Science and Geography California State University Dominguez Hills

We performed a meta-analysis on over 100 studies applying remote sensing(RS)and geographic information systems(GIS)to understand treeline dynamics.A literature search was performed in multiple online databases,including Web of Knowledge(Thomson Reuters),Scopus(Elsevier),bASE(bielefeld Academic Search Engine),CAb Direct,and Google Scholar using treeline-related *** found that RS and GIS use has steadily increased in treeline studies since *** RS and satellite imaging techniques varied from low-resolution MODIS,moderate-resolution Landsat,to high-resolution WorldView and aerial *** papers published in the 1990s used low to moderate resolution sensors such as Landsat Multispectral Scanner and Thematic Mapper,or SPOT PAN(Panchromatic)and MX(Multispectral)RS ***,we observed a rise in high-resolution satellite sensors such as ALOS,GeoEye,IKONOS,and WorldView for mapping current and potential ***,we noticed a shift in emphasis of treeline studies over time:earlier reports focused on mapping treeline positions,whereas RS and GIS are now used to determine the factors that control treeline variation.

关键词： Digital elevation model Geographic information systems Remote sensing Treeline

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A novel correlation for estimation of hydrate forming condition of natural gases

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Journal of Natural Gas Chemistry 2009年第4期18卷 453-457页

作者： Alireza bahadori hari. b. Vuthaluru Department of Chemical Engineering Curtin University of Technology

An inherent problem with natural gas production or transmission is the formation of gas hydrates, which can lead to safety hazards to production/transportation systems and to substantial economic risks. Therefore, an understanding of conditions where hydrates form is necessary to overcome hydrate related issues. Over the years, several models requiring more complicated and longer computations have been proposed for the prediction of hydrate formation conditions of natural gases. For these reasons, it is essential to develop a reliable and simple-to-use method for oil and gas practitioners. The purpose of this study is to formulate a novel empirical correlation for rapid estimation of hydrate formation condition of sweet natural gases. The developed correlation holds for wide range of temperatures （265 - 298 K）, pressures （1200 to 40000 kPa） and molecular weights （16-29）. New proposed correlation shows consistently accurate results across proposed pressure, temperature and molecular weight ranges. This consistency could not be matched by any of the widely accepted existing correlations within the investigated range. For all conditions, new correlation showed average absolute deviation to be less than 0.2% and provided much better results than the widely accepted existing correlations.

关键词： gas hydrate correlation natural gas

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Contemporary and Historic Population Structure of Abies spectabilis at Treeline in barun Valley,Eastern Nepal Himalaya

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Journal of Mountain Science 2015年第3期12卷 558-570页

作者： Parveen Kumar chhetri David M.CAIRNS Department of Geography Texas A&M UniversityCollege Station

Treeline ecotone dynamics of Abies spectabilis （D. Don） Mirb. in the barun valley, Makalu barun National Park, eastern Nepal Himalaya were studied by establishing seven plots （20 m x variable length） from the foresfline to the tree species limit： three plots on the south- and north-facing slopes each （S1-S3, N1-N3）, and one plot on the east- facing slope （E） in the relatively undisturbed forests. A dendroecological method was used to study treeline advance rate and recruitment pattern. In all the plots, most trees established in the early 20th century, and establishment in the second half of the 20th century was confined to the foresfline area. Treeline position has not advanced substantially in the barun valley, with 0nly 22 m average elevational shift in the last 13o years, and with average current shifting rate of 14 cm/yr. Moreover, no significant relationship was found between tree age and elevation on the south-, north-, and east-facing slopes. The number of seedlings and saplings in near the treeline area was negligible compared to that near the foresfline area. Therefore, A. spectabilis treeline response to the temperature change was slow, despite the increasing temperature trend in the region. beside the temperature change, factors such as high inter-annual variability in temperature, dense shrub cover, and local topography also play an important role in treeline advance and controlling recruitment pattern above the treeline.

关键词： Climate change Treeline ecotone Treeline advance Recruitment pattern

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