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Characterizing prediction errors of a new tree height model for cut-to-length Pinus radiata stems through the Burr TypeⅫdistribution

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林业研究:英文版 2023年第6期34卷 1899-1914页

作者： Xinyu Cao Huiquan Bi duncan watt Yun Li School of Information Science and Technology Beijing Forestry UniversityBeijing 100083People’s Republic of China Forest Science NSW Department of Primary IndustriesLevel 304PSQParramattaNSW 2150Australia School of Ecosystem and Forest Sciences Faculty of ScienceThe University of MelbourneWater StreetCreswickVIC 3363Australia Snowy Region Forestry Corporation of NSW76 Capper StreetTumutNSW 2720Australia

Unlike height-diameter equations for standing trees commonly used in forest resources modelling,tree height models for cut-to-length(CTL)stems tend to produce prediction errors whose distributions are not conditionally normal but are rather leptokurtic and *** feature was merely noticed in previous studies but never thoroughly *** study characterized the prediction error distribution of a newly developed such tree height model for Pin us radiata(***)through the three-parameter Burr TypeⅫ(BⅫ)*** model’s prediction errors(ε)exhibited heteroskedasticity conditional mainly on the small end relative diameter of the top log and also on DBH to a minor *** serial correlations were also present in the data.A total of 14 candidate weighting functions were compared to select the best two for weightingεin order to reduce its conditional *** weighted prediction errors(εw)were shifted by a constant to the positive range supported by the BXII *** the distribution of weighted and shifted prediction errors(εw+)was characterized by the BⅫdistribution using maximum likelihood estimation through 1000 times of repeated random sampling,fitting and goodness-of-fit testing,each time by randomly taking only one observation from each tree to circumvent the potential adverse impact of serial correlation in the data on parameter estimation and *** nonparametric two sample Kolmogorov-Smirnov(KS)goodness-of-fit test and its closely related Kuiper’s(KU)test showed the fitted BⅫdistributions provided a good fit to the highly leptokurtic and heavy-tailed distribution ofε.Random samples generated from the fitted BⅫdistributions ofεw+derived from using the best two weighting functions,when back-shifted and unweighted,exhibited distributions that were,in about97 and 95%of the 1000 cases respectively,not statistically different from the distribution ofε.Our results for cut-tolength *** stems repre

关键词： Conditional heteroskedasticity Leptokurtic error distribution Skedactic function Nonlinear quantile regression Weighted prediction errors Serial correlation Random sampling and fitting Nonparametric goodnessof-fit tests

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Reconstructing the size of individual trees using log data from cut-to-length harvesters in Pinus radiata plantations: a case study in NSW, Australia

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Journal of Forestry Research 2018年第1期29卷 13-33页

作者： Kuan Lu Huiquan Bi duncan watt Martin Strandgard Yun Li School of Information Science and Technology Beijing Forestry University Forest Science NSW Department of Industry–Lands and Forestry School of Ecosystem and Forest Sciences The University of Melbourne Snowy Region Forestry Corporation of NSW Australian Forest Operations Research Alliance (AFORA) University of the Sunshine Coast

With their widespread utilization, cut-to-length harvesters have become a major source of ‘‘big data’’ for forest management as they constantly capture, and provide a daily flow of, information on log production and assortment over large operational areas. Harvester data afford the calculation of the total log length between the stump and the last cut but not the total height of trees. They also contain the length and end diameters of individual logs but not always the diameter at breast height overbark（DBHOB） of harvested stems largely because of time lapse, operating and processing issues and other system deficiencies. Even when DBHOB is extracted from harvester data, errors and/or bias of the machine measurements due to the variation in the stump height of harvested stems from that specified for the harvester head prior to harvesting and diameter measurement errors may need to be corrected. This study developed（1） a system of equations for estimating DBHOB of trees from diameter overbark（DOB） measured by a harvester head at any height up to 3 m above ground level and（2） an equation to predict the total height of harvested stems in P. radiata plantations from harvester data. To generate the data required for this purpose, cut-to-length simulations of more than 3000 trees with detailed taper measurements were carried out in the computer using the cutting patterns extracted from the harvester data and stump height survey data from clearfall operations. The equation predicted total tree height from DBHOB, total log length and the small end diameter of the top log. Prediction accuracy for total tree height was evaluated both globally over the entire data space and locally within partitioned subspaces through benchmarking statistics. These statistics were better than that of the conventional height-diameter equations for P. radiata found in the literature, even when they incorporated stand age and the average height and diameter of dominant trees in the stand as predic

关键词： Cut-to-length simulations Harvesters Big data Diameter and height estimation

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A new model for predicting the total tree height for stems cut-to-length by harvesters in Pinus radiata plantations

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Journal of Forestry Research 2021年第1期32卷 21-41页

作者： Chenxi Shan Huiquan Bi duncan watt Yun Li Martin Strandgard Mohammad Reza Ghaff ariyan School of Information Science and Technology Beijing Forestry UniversityBeijing 100083People’s Republic of China Forest Science NSW Department of Primary Industries–ForestryLevel 1210 Valentine AveParramattaNSW 2150Australia School of Ecosystem and Forest Sciences The University of MelbourneParkvilleVIC 3010Australia Snowy Region Forestry Corporation of NSW76 Capper StreetTumutNSW 2720Australia Australian Forest Operations Research Alliance(AFORA) University of the Sunshine CoastSippy DownsQLD 4556Australia

A new model for predicting the total tree height for harvested stems from cut-to-length(CTL)harvester data was constructed for Pinus radiata(***)following a conceptual analysis of relative stem profi les,comparisons of candidate models forms and extensive selections of predictor *** profi les of more than 3000 trees in a taper data set were each processed 6 times through simulated log cutting to generate the data required for this *** CTL simulations not only mimicked but also covered the full range of cutting patterns of nearly 0.45×106 stems harvested during both thinning and harvesting *** single-equation model was estimated through the multipleequation generalized method of moments estimator to obtain effi cient and consistent parameter estimates in the presence of error correlation and heteroscedasticity that were inherent to the systematic structure of the *** predictive performances of our new model in its linear and nonlinear form were evaluated through a leave-one-tree-out cross validation process and compared against that of the only such existing *** evaluations and comparisons were made through benchmarking statistics both globally over the entire data space and locally within specifi c subdivisions of the data *** statistics indicated that the nonlinear form of our model was the best and its linear form ranked *** prediction accuracy of our nonlinear model improved when the total log length represented more than 20%of the total tree *** poorer performance of the existing model was partly attributed to the high degree of multicollinearity among its predictor variables,which led to highly variable and unstable parameter *** new model will facilitate and widen the utilization of harvester data far beyond the current limited use for monitoring and reporting log productions in *** *** will also facilitate the estimation of bark thickness and help make harvester data a

关键词： Stem profi les Cut-to-length simulations Harvester data Model construction Nonlinear multipleequation GMM estimation Benchmarking prediction accuracy

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Insensitive Munitions （IM）： A Key Aspect of Improved Munitions Safety

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含能材料 2006年第5期14卷 323-329页

作者： duncan watt Eric Deschambault Patrick Touze Munitions Safety Information Analysis Center （ MSIAC ） NATO HQ Brussels B-1110 Belgium

The development of Insensitive Munitions (IM) has been progressing for over three decades. Ever since the highly publicized US Navy aircraft carrier accidents in the 1960s to 1980s, there has been a growing recognition of the value of IM. Reminders of the need for IM have been provided all too often in the form of accidents, such as experienced by the US Army at Camp Doha and the prevalence of attacks on military installations around the world. The process for developing IM has improved over the years as technology for mitigating the consequences of accidental initiation has emerged. Early IM developments were based upon replacement of the traditional TNT-based explosives, with their high vulnerability, with reduced vulnerability PBXs. This led to significant improvements, such as that observed with the replacement of H-6 with PBXN-109 in the US Navy Mk82 GP bomb. From the early 1990s, the use of a complete systems approach was highlighted as the optimum method to achieve IM compliance while maintaining or enhancing operational performance. The use of a systems approach has resulted in the fielding of a number of munition systems with significant IM properties. The challenge for the future is to continue the development and fielding of improved performance IM munitions with limited funding for research and the high cost of introducing new ingredients into energetic formulations. A key development to allow continued progress to occur is the introduction of improved versions of current explosive ingredients. The attention focused in the past few years on forms of RDX with reduced shock sensitivity has highlighted the possibility of improving well-known materials. In the near future, the application of materials technology may provide improved versions of other important crystalline energetic materials currently in production or advanced development, including HMX, NTO, CL-20 and ADN and help advance the development of further explosive ingredients such as FOX-7 and LL

关键词： Insensitive Munitions (IM) safety material science crystalline computer simulation

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SnapshotPrune: A Novel Bitcoin-Based Protocol Toward Efficient Pruning and Fast Node Bootstrapping

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Tsinghua Science and Technology 2024年第4期29卷 1037-1052页

作者： Pengfei Huang Xiaojun Ren Teng Huang Arthur Sandor Voundi Koe duncan S Wong Hai Jiang Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006China Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006Chinaand also with Pazhou LabGuangzhou 510330China

Node synchronization is essential for the stability of the Bitcoin network. Critics have raised doubts about the ability of a new node to quickly and efficiently synchronize with the Bitcoin network and alleviate the storage pressure from existing full nodes to stockpile new data. Basic pruning and other techniques have been explored to address these concerns but have been insufficient to reduce node synchronization delay and effectively suppress the growth of synchronized data. In this study, we propose SnapshotPrune, a novel pruning and synchronization protocol that achieves fast node bootstrapping in the Bitcoin blockchain. Real Bitcoin historical data are leveraged to measure the synchronization time and monitor the network traffic during node bootstrapping. The protocol requires data downloads that are 99.70% less than Bitcoin Core, 81% less than CoinPrune, and 60% less than SnapshotSave, thereby saving 97.23% of download time. Findings show that the proposed design enhances the storage efficiency and reduces the node synchronization delay compared with existing techniques. We hypothesize that the efficiency of this protocol increases with the block height.

关键词： synchronization blockchain Unspent Transaction Output(UTXO)pruning snapshot fast bootstrapping

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Cannabinoids and endocannabinoids as therapeutics for nervous system disorders:preclinical models and clinical studies

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Neural Regeneration Research 2024年第4期19卷 788-799页

作者： R.Scott duncan Sean M.Riordan Matthew C.Gernon Peter Koulen Department of Ophthalmology School of MedicineUniversity of Missouri Department of Biomedical Sciences School of MedicineUniversity of Missouri

Cannabinoids are lipophilic substances derived from Cannabis sativa that can exert a variety of effects in the human *** have been studied in cellular and animal models as well as in human clinical trials for their therapeutic benefits in several human *** of these include central nervous system(CNS)diseases and dysfunctions such as forms of epilepsy,multiple sclerosis,Parkinson’s disease,pain and neuropsychiatric *** addition,the endogenously produced cannabinoid lipids,endocannabinoids,are critical for normal CNS function,and if controlled or modified,may represent an additional therapeutic avenue for CNS *** review discusses in vitro cellular,ex vivo tissue and in vivo animal model studies on cannabinoids and their utility as therapeutics in multiple CNS *** addition,the review provides an overview on the use of cannabinoids in human clinical trials for a variety of CNS *** and endocannabinoids hold promise for use as disease modifiers and therapeutic agents for the prevention or treatment of neurodegenerative diseases and neurological disorders.

关键词： anandamide cannabidiol cannabinoid endocannabinoid epilepsy multiple sclerosis neurodegeneration neuroprotection tetrahydrocannabinol

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Understanding the catalysis of chromium trioxide added magnesium hydride for hydrogen storage and Li ion battery applications

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Journal of Magnesium and Alloys 2024年第3期12卷 1117-1130页

作者： D.Pukazhselvan IhsanÇaha Catarina de Lemos Sergey M.Mikhalev Francis Leonard Deepak duncan Paul Fagg Department of Mechanical Engineering TEMA-Centre for Mechanical Technology and AutomationUniversity of AveiroAveiro 3810-193Portugal LASI-Intelligent Systems Associate Laboratory Guimarães 4800-058Portugal Nanostructured Materials Group International Iberian Nanotechnology Laboratory(INL)Avenida Mestre Jose VeigaBraga 4715-330Portugal

This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).We have observed that a 5 wt.%CrO_(3) additive reduces the dehydrogenation activation energy of MgH_(2) by 68 kJ/mol and lowers the required dehydrogenation temperature by 80℃.CrO_(3) added MgH_(2) was also tested as an anode in an Li ion battery,and it is possible to deliver over 90%of the total theoretical capacity(2038 mAh/g).Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH_(2).In depth characterization study by X-ray diffraction(XRD)technique provides convincing evidence that the CrO_(3) additive interacts with MgH_(2) and produces Cr/MgO *** free energy analyses confirm the thermodynamic feasibility of conversion from MgH_(2)/CrO_(3) to MgO/Cr,which is well supported by the identification of Cr(0)in the powder by X ray photoelectron spectroscopy(XPS)*** high resolution transmission electron microscopy(HRTEM)and energy dispersive spectroscopy(EDS)we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt *** is also convincing ground to consider that MgO rock salt accommodates Cr in the *** observations support the argument that creation of active metal–metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH_(2),both for the improved storage of hydrogen and lithium.

关键词： Hydrogen storage Rechargeable batteries Binary hydrides Metal oxides Catalytic mechanism.

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Olympic Games and 24-hour movement behaviors:A match worth making

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Journal of Sport and Health Science 2024年第6期13卷 728-731页

作者： Mark S.Tremblay Nicholas Kuzik Markus J.duncan Diego Augusto Santos Silva CHEO Research Institute OttawaON K1H 8L1Canada Department of Pediatrics University of OttawaOttawaON K1H 8L1Canada Federal University of Santa Catarina FlorianopolisSanta Catarina 88040-900Brazil

*** The Olympic motto,"Faster,Higher,Stronger-Together",represents the pursuit of athletic excellence,united as a global community."Excellence,respect and friendship"are the Olympic *** the motto and values are multifaceted and holistic in nature,and all-encompassing in their reach while recognizing no single entity rises above the ***,these foundational statements anchor the Olympic movement in its quest to build a better world through sport.

关键词： movement Together pursuit

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Towards precision 24-hour movement behavior recommendations—The next new paradigm?

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Journal of Sport and Health Science 2024年第6期13卷 743-748页

作者： Mark S.Tremblay Markus J.duncan Nicholas Kuzik Diego Augusto Santos Silva Valerie Carson CHEO Research Institute OttawaON K1H 8L1Canada Department of Pediatrics University of OttawaOttawaON K1H 8L1Canada Federal University of Santa Catarina Santa Catarina 88040900Brazil Faculty of Kinesiology Sportand RecreationUniversity of AlbertaEdmontonAB T6G 2H9Canada

*** The importance of physical activity(PA)for health is unequivocal.^(1)Accordingly,population-based recommendations for exercise,and more recently public health guidelines for PA,have been developed and released by authoritative groups for many decades.^(2)Such guidelines emerged with leadership from the exercise physiology discipline and were rooted in,and loyal to,the importance of moderate-to-vigorous intensity PA(MVPA)or exercise.

关键词： movement behavior exercise

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Quantitative assessment of the impact of a triage physician on the Accreditation Council for Graduate Medical Education resident milestones in the emergency department

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World Journal of Emergency Medicine 2024年第3期15卷 220-222页

作者： Julie Cueva duncan Grossman Vishnu Muppala Arlene Chung Mahlaqa Butt Jefferson Drapkin Antonios Likourezos Errel Khordipour Department of Emergency Medicine Maimonides Medical CenterNew York 11219USA

The “door-to-doctor” time for patients to be seen by a physician is an increasingly studied *** may shorten this time by implementing a triage physician (TP).The exact role of a TP may vary across *** put in preliminary orders for lab work,imaging,and treatment,and decide treatment location for further *** the prevalence of TPs grows,its effect on resident education in academic emergency departments (EDs) remains *** implemented a TP in the spring of 2016 and assessed resident physicians before and after implementation.

关键词： physician doctor treatment

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