On the Elastic Vibration Model for High Length-Diameter Ratio Rocket with Attitude Control System

An elastic vibration model for high length diameter ratio spinning rocket with attitude control system which can be used for trajectory simulation is established. The basic theory of elastic dynamics and vibration dynamics were both used to set up the elastic vibration model of rocket body. In order to study the problem more conveniently, the rocket's body was simplified to be an even beam with two free ends. The model was validated by simulation results and the test data.

Individual-tree diameter growth model for Korean pine plantations based on optimized interpolation of meteorological variables

To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three approaches to interpolate meteorological variables during the growing season(i.e.,May-September) were compared in Heilongjiang Province,China.Optimized meteorological variable interpolation results were then combined with stand and individual tree variables,based on data from 56 sample plots and 2886 sample trees from Korean pine plantations in two regions of the province to develop an individualtree diameter growth model(Model I) and an individualtree diameter growth model with meteorological variables(Model Ⅱ) using a stepwise regression method.Moreover,an individual-tree diameter growth model with regional effects(Model Ⅲ) was developed using dummy variables in the regression,and the significance of introducing these dummy variables was verified with an F-test statistical analysis.The models were validated using an independent data set,and the predictive performance of the three models was assessed via the adjusted coefficient of determination(R_(a)^(2)) and root mean square error(RMSE).The results suggest that the growth increment in tree diameter of Korean pine plantations was significantly correlated with the natural logarithm of initial diameter(ln D),stand basal area(BAS),logarithmic deformation of the stand density index(ln SDI),ratio of basal area of trees larger than the subject tree to their initial diameter at breast height(DBH)(BAL/D),and the maximum growingseason precipitation(Pgmax).The individual-tree diameter growth models of Korean pine plantations developed in this study will provide a good basis for estimating and predicting growth increments of Korean pine forests over larger areas.

A three-year longitudinal study of the relation between left atrial diameter remodeling and atrial fibrillation ablation outcome

在 post-radiofrequency 导管脱离(RFCA ) 的地位上改变 atrial 纤维性颤动(AF ) 的左 atrial 直径(男孩) 的 BackgroundThe 长期的预示的影响是不清楚的。这研究从 3 年的 echocardiographic 数据雇用了一个二阶段的模特儿比用基线 LAD.MethodsData 的模型来自有经历 RFCA 的药倔强的 AF 的 263 个连续病人是回顾地镇定的的查明二阶段的模型是否更有利地预言 RFCA 结果。男孩的常规 echocardiographic 大小在 RFCA 以后在基线， 1， 3， 6，和 12 个月然后每 6 个月被执行。性别，年龄， AF 的类型， RFCA 的数字，和 AF 地位被记录。我们获得实际(预言) 用一个纵的线性混合模型的 3 年的男孩(1 st 舞台) 。逻辑回归基于基线男孩(模型 1 ) 当模特儿，实际(预言)3 年的男孩(模型 2 )(2 nd 舞台) ，并且观察 3 年的男孩(模型 3 ) 被构造预言 RFCA 结果。在操作典型曲线(AUC ) 的接收装置下面的区域被用来估计弄平的曲线显示了的 models.ResultsThe lowess 的表演 LAD 在开始的三个月拒绝了并且在 RFCA 以后仍然保持稳定直到 36 个月。男孩减小的度被基线男孩显著地影响。非发作性的 AF，大男孩和女性是 AF 复发的重要预言者。模型 2 在纵的基于学习的二阶段的模型超过的三 models.ConclusionsThis 之中有最大的 AUC 用基线男孩的原来的逻辑模型。非发作性的 AF，更大的男孩和女性是 RFCA 失败的重要预言者。

Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height （dbh） can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter （h-d） models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods： We develop unconstrained generalized additive models （GAM） and shape constrained generalized additive models （SCAM） for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results： Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand, The definition of constraints leads only to marginal or minor decline in the model statistics like AIC An observed structured spatial trend in tree height is modelled via 2-dimensional surface fitting. Conclusions： We demonstrate that the SCAM approach allows optimal regression modelling flexibility similar to the standard GAM but with the additional possibility of defining specific constraints for the model effects. The longitudinal character of the model allows for tree height imputation for the current status of forests but also for future tree height prediction.

Species-specific,pan-European diameter increment models based on data of 2.3 million trees

Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country-and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition.Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from10% to 53% depending on the species. Variables related to forest structure(basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species.Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etc.

Modeling of the height–diameter relationship using an allometric equation model:a case study of stands of Phyllostachys edulis

Understanding the relationship between tree height （H） and diameter at breast height （D） is vital to forest design, monitoring and biomass estimation. We developed an allometric equation model and tested its applicability for unevenly aged stands of moso bamboo forest at a regional scale. Field data were collected for 21 plots. Based on these data, we identified two strong power relationships： a corre- lation between the mean bamboo height （Hm） and the upper mean H （Hu）, and a correlation between the mean D （Din） and the upper mean D （Du）. Simulation results derived from the aUometric equation model were in good agreement with observed culms derived from the field data for the 21 stands, with a root-mean-square error and relative root-mean-square error of 1.40 m and 13.41%, respectively. These results demonstrate that the allometric equation model had a strong predictive power in the unevenly aged stands at a regional scale. In addition, the estimated average height-diameter （H-D） model for South Anhui Province was used to predict H for the same type of bamboo in Hunan Province based on the measured D, and the results were highly similar. The allometric equation model has multiple uses at the regional scale, including the evaluation of the variation in the H- D relationship among regions. The model describes the average H-D relationship without considering the effects caused by variation in site conditions, tree density and other factors.

Droplets diameter distribution using maximum entropy formulation combined with a new energy-based sub-model

The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atomization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation(MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model(EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model(MEF/EBM) is in good agreement with the available experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model(MEF/EBM) can be used to well predict the droplet size distribution at the primary breakup.

Longitudinal height-diameter curves for Norway spruce, Scots pine and silver birch in Norway based on shape constraint additive regression models

Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.

Effect of sediment on vertical dynamic impedance of rock-socketed pile with large diameter

Based on the fictitious soil pile model, the effect of sediment on the vertical dynamic impedance of rock-socketed pile with large diameter was theoretically studied by means of Laplace transform technique and impedance function transfer method. Firstly, the sediment under rock-socketed pile was assumed to be fictitious soil pile with the same sectional area. The Rayleigh-Love rode model was used to simulate the rock-socketed pile and the fictitious soil pile with the consideration of the lateral inertial effect of large-diameter pile. The layered surrounding soils and bedrock were modeled by the plane strain model. Then, by virtue of the initial conditions and boundary conditions of the soil pile system, the analytical solution of the vertical dynamic impedance at the head of rock-socketed pile was derived for the arbitrary excitation acting on the pile head. Lastly, based on the presented analytical solution, the effect of sediment properties, bedrock property and lateral inertial effect on the vertical dynamic impedance at rock-socketed pile head were investigated in detail. It is shown that the sediment properties have significant effect on the vertical dynamic impedance at the rock-socketed pile head. The ability of soil-pile system to resist dynamic vertical deformation is weakened with the increase of sediment thickness, but amplified with the increase of shear wave velocity of sediment. The ability of soil pile system to resist dynamic vertical deformation is amplified with the bedrock property improving, but the ability of soil-pile system to resist vertical vibration is weakened with the improvement of bedrock property.

Diameter distribution of trees in natural stands managed on polycyclic cutting system

Diameter frequency distribution in a specific stand provides basic information for forest resources management. In this study, four probability models were applied to analyze diameter distribution of natural forests after selective cutting with different intensities （low intensity of 13.0% in volume, medium intensity of 29.1%, high intensity of 45.8%, and extra-high intensity of 67.1%） The results show that the skewness and kurtosis of the four models are positive except that of low intensity selective cutting, which suggest that the number of small-size trees dominate the stand. The more intensity of selective cutting, the wider range of diameter distributions. The diameter structure of selective cutting with low intensity met Weibull and Beta distributions; that of medium intensity met Weibull, negative exponential as well as Gamma distributions; that of high intensity cutting met Weibull and negative exponential distributions, but that of extra-high intensity could not meet any above model. Weibull distribution model fits better than others regarding the structure of diameter distribution in natural forests managed on polycyclic cutting system. The results will provide basic information for sustainable management for mixed natural stands managed on a polycyclic cutting system.

THEORETICAL AND EXPERIMENTAL STUDIES ON BUBBLE DIAMETER AND GAS HOLDUP IN AERATED STIRRED TANKS

1 INTRODUCTIONBubble diameter distribution and gas holdup are very important parameters indicatingthe characteristics of gas-liquid dispersion,works done are mostly experimentalobservation.Theoretical analysis of bubble diameter has been mostly focused on thebreak-up of bubbles in the impeller region,and only the theoretical relationship be-tween bubble diameter and operating variables in the impeller region has been

Accuracy assessment and error analysis for diameter at breast height measurement of trees obtained using a novel backpack LiDAR system

Background: The LiBackpack is a recently developed backpack light detection and ranging(LiDAR) system that combines the flexibility of human walking with the nearby measurement in all directions to provide a novel and efficient approach to LiDAR remote sensing, especially useful for forest structure inventory. However, the measurement accuracy and error sources have not been systematically explored for this system.Method: In this study, we used the LiBackpack D-50 system to measure the diameter at breast height(DBH) for a Pinus sylvestris tree population in the Saihanba National Forest Park of China, and estimated the accuracy of LiBackpack measurements of DBH based on comparisons with manually measured DBH values in the field. We determined the optimal vertical slice thickness of the point cloud sample for achieving the most stable and accurate LiBackpack measurements of DBH for this tree species, and explored the effects of different factors on the measurement error.Result: 1) A vertical thickness of 30 cm for the point cloud sample slice provided the highest fitting accuracy(adjusted R2= 0.89, Root Mean Squared Error(RMSE) = 20.85 mm);2) the point cloud density had a significant negative, logarithmic relationship with measurement error of DBH and it explained 35.1% of the measurement error;3) the LiBackpack measurements of DBH were generally smaller than the manually measured values, and the corresponding measurement errors increased for larger trees;and 4) by considering the effect of the point cloud density correction, a transitional model can be fitted to approximate field measured DBH using LiBackpackscanned value with satisfactory accuracy(adjusted R2= 0.920;RMSE = 14.77 mm), and decrease the predicting error by 29.2%. Our study confirmed the reliability of the novel LiBackpack system in accurate forestry inventory, set up a useful transitional model between scanning data and the traditional manual-measured data specifically for P.sylvestris, and implied the applicable substitution of this new approach for more species, with necessary parameter calibration.

Estimating Pinus palustris tree diameter and stem volume from tree height,crown area and stand-level parameters

Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height （dbh） and merchantable stem volume （V） using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height （H） and crown area （CA）. Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data.

Are models of volumetric production at the diametric distribution and total stand level mutually compatible?

The objective of this work was to compare estimates generated by a diametric distribution model and a total stand model against the pre-cut inventory.The model efficiency was also evaluated.Data were evaluated from 30 permanent sample plots in a Eucalyptus urophylla stand,comprising 24 sample plots used for model fitting,and six sample plots for validation.The volume of wood per hectare was estimated for different productive units(sites),using 7 years as the reference age.The model adjustment quality was verified by adjustment and precision statistics:the correlation between observed and predicted variables,root mean square error percentage,graphical analysis of residual distribution,and a frequency histogram for classes of relative errors and validation.Although the two-parameter Weibull probability density function adhered to the data for tree evolution in diameter classes for the reference age(7 years)in the different productivity classes,it generated imprecise estimates of the number of individuals.Consequently,it produced inaccurate volumetric production estimates.The total stand model provided reliable projections of production volumes in different productivity classes for both adjustment types,showing compatibility with the pre-cut inventory according to a Tukey test.In summary,the total stand model generated estimates that were compatible with the pre-cut inventory while the diametric distribution model did not.

Comparison of the Five Different Methods in Arterial Diameter Measurement

Background/Aims: In this study, the different types of arterial diameter measurement methods were com-pared with each other on rat model. Methods: The study was planned in three phases. In phase 1, all subjects (n = 30) underwent high resolution B-mode ultrasound examination and external diameter of the right com-mon carotid artery (RCCA) was measured. In phase 2, RCCA was explored. In phase 3, rats were put into three groups. Group 1 was kept at -20oC, group 2 was embedded in 4% formaldehyde solution. In group 3, circulatory system was filled with %20 latex solution. In all groups, digital image of the RCCA was taken after the processes mentioned above. Images were assessed by Image – Pro Plus software. Results: The greatest average diameter was observed in the high resolution B-mode ultrasound (phase 1). In group 1 and 2, direct measurement of the RCCA on living animal (phase 2) gave significantly wider diameter than those obtained at phase 3 in the same groups. Direct (phase 2) and latex (phase 3) measurements were equal in group 3. Conclusion: High resolution B-mode ultrasound gives larger, probably actual diameter of the artery. Latex injection results might correspond those encountered during operation.

Diameter信令网业务模型研究及展望

随着4G业务的发展,控制面网元对Diameter信令网的支撑要求与日俱增;本文分析了Diameter信令网面临的问题,提出了应对策略及建议,同时,分析了目前中国移动的S6a接口业务特性,结合现网历史统计数据以及信令流程特征,提出了业务模型的核定方法,使得Diameter信令网资源配置能够更符合未来4G业务发展的实际需求,最后展望了Diameter信令网未来演进方向。

Diameter信令消息模型优化

随着4G和VoLTE的商用部署,4G数据上网、VoLTE高清语音和PCC能力开放等业务快速发展,对Diameter信令网转接能力提出了更高的要求。结合Diameter信令网运行数据,对各信令接口消息模型进行分析和修正,同时针对网络发展的演进及新业务引入对信令网的要求,补充完善消息模型,为Diameter信令网络规划建设提供借鉴和参考。

广西沃柑果实横径生长动态及模型构建

【目的】研究广西沃柑果实横径的生长动态并构建数学模型,为提升其品质和产量提供科学依据。【方法】以沃柑为材料,于稳果后,连续两年每月1日、15日通过“定园、定点、定果、定期”的方法测量并记录广西桂南、桂中、桂北15个果园的沃柑横径数据,直至采收期,研究沃柑横径的变化动态,考察年终横径与各生长节点,月度横径增加值与主要气象信息的相关性并建立数学模型。【结果】各个果园最终的横径差别较大,达到极显著差异水平,多个果园的横径有待提升;对比气象数据,选定2021—2022年度的沃柑横径数据为正常年份数据,翌年1月15日果实横径平均值为69.85 mm,最高的果园达75.33 mm,最小的61.55 mm;以80、75、70、65、60、55 mm为等级,构建桂南、桂北和桂中沃柑果实横径生长动态对照表、横径月度增加值对照表;分别建立年终沃柑横径数值与各生长节点,横径月度增加值与主要月度气象信息的数学模型,年终横径与7月15日呈显著正相关,与8月15日以后呈极显著正相关,至11月1日达到极显著的0.934 0;月度增加值与降雨、温度相关系数分别为显著的0.791 8和极显著的0.879 1。【结论】广西沃柑提质增产仍存在较大空间,可结合当期横径生长对照表、定期差值对照表,科学合理安排水肥药的灌溉来进一步加速果实膨大,从而提升效益。