Cumulative Distribution Curves Research Articles

A novel index for assessing the water quality of urban landscape lakes based on water transparency

Assessment of the aesthetic and recreational value of urban landscape lakes (ULLs) is often required but there has not been a water quality index specifically applicable for such a purpose. Under a consideration that water transparency in terms of Secchi Depth (SD), to a large extent, determines the landscape effect, a study was conducted to identify the major parameters that strongly influence SD and to develop a novel water quality index. By theoretical analyses, it was found that SD is mainly influenced by the contents of chlorophyll a, inorganic suspended solids and organic detritus in water, which collectively relate to eight independent water quality, hydraulic, and environmental parameters, including SS, DO, COD, NH4+-N, NO3−-N, TP, HRT, and water temperature T. A composite index was then proposed in the form of WQIULL = ∏i=1nqiwi (n = 8). Using the data of field survey of 166 ULLs in China, the cumulative probability distribution curve of each sub-index qi was characterized. Sensitive analysis was conducted for the determination of the sub-index weight (wi) for each qi under the consideration of two typical scenarios of ULL replenishment by stream water (traditional source) and reclaimed water (alternative source) regarding the variation of parameter on SD. With all wi (i = 1 to 8) thus determined, WQIULL was calculated for each of the ULLs surveyed. All the calculated values of WQIULL showed a good correlative relationship with the SD values practically measured (R2 = 0.8948), indicating that the novel water quality index developed could effectively indicate the satisfactory degree of the lake water quality in terms of water landscape. Further by comparing the dimensionless WQIULL (ranging between 0 and 100) with the practically acceptable SD based on experiences in China, the method for classification of ULLs by WQIULL calculation was formulated.

Characterizing pollution and source identification of heavy metals in soils using geochemical baseline and PMF approach

It is necessary to establish local geochemical baseline concentrations (GBCs) due to the lack or the inapplicability of regional background values in the study area. The establishment of GBCs of heavy metal (HM) in soil helps in making the accurate assessment of pollution, and then provides a basis for pollution control. Based on this, a case study was undertaken to study the GBCs of the Jiedong District, Guangdong Province, China. In this research, cumulative frequency distribution curves were utilized to determine the local GBCs in the subsoils. The determined GBCs of Cr, Hg, As, Pb, Ni, Cd, Cu, Zn, Co and V were 39.91, 0.072, 11.48, 47.62, 12.70, 0.17, 14.22, 64.54, 6.31, and 68.14 mg/kg, respectively. The average concentrations of Hg, As, Pb, Cd, Cu and Zn in the topsoils exceeded the corresponding baseline concentrations. In particular, the contents of Cd and Hg were 1.53 and 2.22 times higher than GBCs. According to this baseline criterion, enrichment factor (EF), pollution load index (PLI) and ecological risk index (RI) were applied to assessing HM pollution. EF and PLI suggested that most areas were under moderate contamination, while Hg and Cd pollution was more serious. And the RI values presented that the potential ecological risks were low in most parts of the study area. The possible origins of HMs were identified by combining positive matrix factorization with EF and geostatistics. Comprehensive analysis indicated that Hg and Cd were related to industrial activities, such as textile and garment processing, plastic and rubber production and metal manufacturing. Arsenic and part of Cu mainly came from agricultural activities, namely the use of pesticides, fertilizers and livestock manures. Lead and Zn were mainly attributed to traffic emissions. Chromium, Ni, V, Co, and part of Cu were originated from natural source controlled by parent materials. The corresponding contributions of these sources were 20.61%, 24.20%, 19.22% and 35.97%, respectively. This work provides information to prevent and control the soil HM pollution by proposing the efficient management of anthropogenic sources.

An approach towards estimating critical value of waiting time at transit stops

Waiting time at transit stops is found to be an influential policy variable for a passenger's decision on whether to undertake a given transit service. With regard to policy framework for improvement of operational service headway of a transit service and thereby its waiting time, the necessity to have knowledge on its critical value becomes inevitable. The critical value of waiting time for passengers waiting at transit stops is that duration beyond which passengers are found to be no more interested to wait for a that transit service. The paper demonstrates an approach for estimating the critical value of waiting time at urban transit stops with reference to public transport services such as city bus and shared-auto operational in Bhubaneswar, India. The critical value of waiting time is estimated from the point on cumulative distribution curve of waiting time frequency distribution, at which the maximum rate of change of the slope of curve occurs. The work assumes two positively skewed distributions such as gamma and log-normal for observed distributional pattern of waiting time. The work identifies that gamma distribution is comparatively fitting the observed data better than log-normal distribution. The study reveals that the critical value of waiting time for city bus passengers is about twice than that of shared auto passengers. Though, the study presents new information on critical values of waiting time with reference to an urban area of a developing country, it also demonstrates an experience on application of probability distribution functions for understanding distributional pattern of waiting time. • Estimation of critical value of waiting time at urban transit stops. • The critical value is estimated considering gamma and log-normal distribution. • The above values are estimated for city bus and shared-auto passengers.

Effects of Compound Sand Barrier for Habitat Restoration on Sediment Grain-size Distribution in Ulan Buh Desert

Wind erosion is a huge challenge for ecologists to stabilize sand dunes and to change them into stable productive ecosystems. In order to better understand its role in the process of ecological restoration, the sediment grain-size characteristics of compound sand barrier were evaluated through field experimental observation. The results indicated that the compound sand barrier was mainly composed of extremely fine sand and fine sand, and the fine sand and extremely fine sand in the inner side were higher than the east and west sides of the compound sand barrier. Due to the blocking effect of compound sand barrier, the Sorting Coefficient became better, the Skewness belonged to the positive deviation and the Kurtosis presented leptokurtosis distribution. Moreover, while the cumulative frequency distribution curve in the inner side became steeper, the slope increased and reached the top of the curve ahead of time. The effect of wind environment and vegetation coverage on the surface sediments showed that the average annual wind velocity and vegetation coverage was negatively correlated with the average grain-size, but positively correlated with the Sorting Coefficient. There was a significant correlation among the annual wind speed, vegetation coverage, average grain-size and Sorting Coefficient, which indicated that vegetation coverage and wind environment was the key factor leading to the difference of surface sediments in this area. Collectively, the establishment of compound sand barrier is one of the most effective methods of sand-fixing with engineering measure in the arid desert regions. Therefore, given the complexities of agricultural systems, stubble retention and black film covered during harvesting and incorporation of the stubble into soil in the next spring appears to be the best choice in the dry northern China where farmlands suffer serious wind erosion.

3D CPFD Simulation of Circulating Fluidized Bed Downer and Riser: Comparisons of Flow Structure and Solids Back-Mixing Behavior

The difference of gas-solids flow between a circulating fluidized bed (CFB) downer and riser was compared by computational particle fluid dynamics (CPFD) approach. The comparison was conducted under the same operating conditions. Simulation results demonstrated that the downer showed much more uniform solids holdup and solids velocity distribution compared with the riser. The radial non-uniformity index of the solids holdup in the riser was over 10 times than that in the downer. In addition, small clusters tended to be present in the whole downer, large clusters tended to be present near the wall in riser. It was found that the different cluster behavior is important in determining the different flow behaviors of solids in the downer and riser. While the particle residence time increased evenly along the downward direction in the downer, particles with both shorter and longer residence time were predicted in the whole riser. The nearly vertical cumulative residence time distribution (RTD) curve in the downer further demonstrated that the solids back-mixing in the downer is limited while that in the riser is severe. Solids turbulence in the downer was much weaker compared with the riser, while the large clusters formation near the wall in the riser would hinder solids transportation ability.

Estimating the distribution of enterprise values with quantile neural networks

The probability density function of enterprise values may be more precise and useful in the cases of corporate investment, financing, or transactions. Although the quantile regression analysis can generate a set of models for a series of quantiles, it cannot generate the probability density function of the dependent variable. Therefore, this paper proposes a novel method of employing prediction results of the quantile neural networks to build probability density functions with which we can effectively assess enterprise values. Empirical evidence reveals that the estimated cumulative lognormal distribution curves of the price-to-book value ratio (PBR) and the data are well matched. In addition, the corporate market value is equal to the PBR multiplied by the corporate stockholders equity. Thus, the corporate market value is also a lognormal distribution. PBR distributions of building and construction industries are more tilted to the left, implying that enterprise values of building and construction industries are lower than those of other industries with the same stockholders equity and return on equity.

Effect of Material Properties and Strain Rate on Fragmentation of Anisotropic Rock

In order to investigate the effect of the microproperties of bedding and strain rate on the fragment size distributions of layered phyllite with different bedding dip angles, a split Hopkinson pressure numerical model was established and verified by comparing with the experimental results. A new method to obtain reasonable layered rock dynamic simulation result was proposed. Then, the cumulative distribution curve and average fragment size of layered rocks were calculated after changing the strain rate and microparameters of bedding in the model. The results showed that the samples tend to become pulverized under high strain rate, and it was harder for the samples with low dip angle to be damaged if the bedding shear strength is added, while the fragmentation of high angle samples did not change significantly. Furthermore, the failure of layered specimens was not affected by the tensile strength and stiffness. The wider bedding and narrower space promoted the crack initiation and propagation.

Artificial soil nutrient, aggregate stability and soil quality index of restored cut slopes along altitude gradient in southwest China.

In the subalpine mountainous region of southwest China, the artificial soil properties of restored cut slopes along the altitude gradient were studied, including available nitrogen (AN), available phosphorus (AP), available potassium (AK), urease (UR), sucrase (SC), protease (PR), catalase (CAT), texture, and aggregate stability of soil. Soil aggregatet stability by mean weight diameter (MWD), geometric mean diameter (GMD), structure failure rate (P), index of unstable aggregates (IUA) and area difference of dry and wet sieve cumulative distribution curve (ΔS) were measured and analyzed. It was found that available soil nutrients, UR, and CAT activities increased initially and then decreased, but the texture of soil was finer, and aggregate structure tended to be more stable along with an increase in the altitude gradient. The soil aggregate stability index that MWD, GMD, P, IUA, and ΔS indicated that the higher the altitude, the stability of soil aggregates was better. Principal component analysis (PCA) was used to determine the soil quality index (SQI). The obtained results from this study showed that the artificial soil quality of the cut slopes was better at a higher altitude compared to a lower altitude. These results provide a reference for the improvement of artificial soil properties of cut slopes and their quality in the future. It is necessary to pay attention to the soil quality management at a low-altitude area and reform the soil nutrients, enzyme activities, and soil structure for the restored cut slopes in the mountainous subalpine highway of southwest China.

Model Validation Methods for Multiple Correlated Responses via Covariance-Overlap Based Distance

Abstract Model validation methods have been widely used in engineering design to provide a quantified assessment of the agreement between simulation predictions and experimental observations. For the validation of simulation models with multiple correlated outputs, not only the uncertainty of the responses but also the correlation between them needs to be considered. Most of the existing validation methods for multiple correlated responses focus on the area metric, which only compares the overall area difference between the two cumulative probability distribution curves. The differences in the distributions of the data sets are not fully utilized. In this paper, two covariance-overlap based model validation (COMV) methods are proposed for the validation of multiple correlated responses. The COMV method is used for a single validation site, while the covariance-overlap pooling based model validation (COPMV) method can pool the evidence from different validation sites into a scalar measure to give a global evaluation about the candidate model. The effectiveness and merits of the proposed methods are demonstrated by comparing with three different existing validation methods on three numerical examples and a practical engineering problem of a turbine blade validation example. The influence of sample size and the number of partitions in the proposed methods are also discussed. Results show that the proposed method shows better performance on the uncertainty estimation of different computational models, which is useful for practical engineering design problems with multiple correlated responses.

Analysis of mathematical models for description of the fractional composition of disperse elastic fillers

The paper presents a comparative analysis of integral and differential mathematical models describing the particle size distribution of dispersed elastic fillers. Crushed vulcanizates obtained by high temperature shear grinding were studied as objects of research. Technogenic waste – waste passenger car tires and rubber elements of gas mask facepieces – were used as raw materials. Data on the distribution of the crushed vulcanizate particles were obtained by laser diffraction using the particle size analyzer Fritsch Analysette 22 Microtec plus (“Fritsch”, Germany). It was found that the distribution curves are unimodal asymmetric curves. Search and analysis of mathematical models were carried out using a specialized software product TableCurve 2D v5.01 (Jandel Scientific). Four- and five-parameter equations pertaining to the class of logistic models were tested to describe the integral cumulative distribution curves of the rubber powder particles. In order to justify the choice of a suitable mathematical model to describe the fractional composition of the crushed vulcanizes, the adequacy of the models was assessed, the structural characteristics of the variation series, the statistical moments of distribution and the indicators of its shape were determined. It was found that according to a number of criteria it is appropriate to use the logarithmically normal distribution function for the description and analysis of the rubber powders fractional composition. It is suggested that regardless of the nature of the feedstock, the described implementation of high temperature shear grinding provides products having an identical shape of rubber powder particles size distribution.

Sedimentary environment and facies of the Huagang Formation in the northern central Xihu Depression, East China Sea Basin, China

The sedimentary facies of the Huagang Formation, the major petroleum exploration horizon in the Xihu Depression in the East China Sea Basin, have not been well constrained, owing to limited drilling and core recovery. Interpretations are vague and vary from beach bar, braided river and braided-river delta front sediments. In this paper, the paleosedimentary environments of the Huagang Formation are discussed based on detailed organic and inorganic geochemical analysis and proxies used to interpret the sedimentary facies. Kerogen, dominated by sapropelinite, is mainly of Type I and Type II, and n-Paraffins are dominated by short-chain and medium-chain, with no obvious odd-over-even advantages. The distribution of isoprenoid alkanes and steroids indicates that the organic matter in mudstones is mainly of lacustrine and mixed origins. Elemental ratios of Th/U (4–6), V/Cr (1–4), Ni/Co (3–11) and V/(V + Ni) (0.5–0.75) indicate that in the area studied, the Huagang Formation was deposited under anoxic to reduced conditions with some oxygen-enriched horizons. Both inorganic and organic geochemical signatures show that the Huagang Formation was mainly deposited in an aquatic environment but with some minor periods of subaerial exposure. The sequence of the Huagang Formation is characterised by interbedded grey-white thick sandstones and grey-black thin mudstones. Normally graded cycles are widely developed, with rare mudstone in the upper part and scoured surfaces at the base. The cumulative grainsize distribution curve is mainly a two-stage type. The sedimentary facies indicative markers are dominated by braided-river channel deposits and combined with the paleosedimentary environments it is inferred that the sedimentary system in the study area was typical of a braided-river delta front. The cores available were intensively analysed using a hand-held X-ray fluorescence spectrometer to probe the variations in the paleoclimate and show that the braided-river channels were controlled by paleoclimate. During arid climatic settings, the sediments within individual channels were thin, and grainsizes varied significantly; at the base of each channel, basal conglomerates were common. In contrast, under humid climatic settings, thin multi-stage channels were superimposed, and the bottom often developed erosion surface.KEY POINTSThe paleosedimentary environments are discussed based on detailed organic and inorganic geochemical analysis.The Huagang Formation was deposited in a freshwater lacustrine basin under warm and humid climatic settings.The Huagang Formation is characterised by braided-river delta front facies.The development of braided-river channels was controlled by paleoclimate.

On the use of nonparametric tests for comparing immunological Reverse Cumulative distribution curves (RCDCs)

Reverse Cumulative Distribution Curves (RCDCs) have proven to be a useful tool in summarizing immune response profiles in vaccine studies since their introduction by Reed, Meade, and Steinhoff (RMS) (1995). They are able to display virtually all of the treatment data and characterize summary statistics such as means or even their confidence intervals (CIs) that might be obscure. RMS mentioned their similarity to survival curves often used to summarize time-to-event data which are usually not normally distributed. The RCDCs, while intuitively pleasing and useful, contain important properties which allow for more powerful statistical applications. In this paper, we will suggest several widely used rank-based tests to compare the curves in the context of vaccine studies. These rank-based tests allow for comparisons between treatments, for stratified analyses, weighted analyses, and other modifications that make them the alternative of parametric analyses without the normality assumptions.Clinical trial identification: NCT01712984 and NCT01230957.

Prognosis of clear cell renal cell carcinoma (ccRCC) based on a six-lncRNA-based risk score: an investigation based on RNA-sequencing data

BackgroundThe scientific understanding of long non-coding RNAs (lncRNAs) has improved in recent decades. Nevertheless, there has been little research into the role that lncRNAs play in clear cell renal cell carcinoma (ccRCC). More lncRNAs are assumed to influence the progression of ccRCC via their own molecular mechanisms.MethodsThis study investigated the prognostic significance of differentially expressed lncRNAs by mining high-throughput lncRNA-sequencing data from The Cancer Genome Atlas (TCGA) containing 13,198 lncRNAs from 539 patients. Differentially expressed lncRNAs were assessed using the R packages edgeR and DESeq. The prognostic significance of lncRNAs was measured using univariate Cox proportional hazards regression. ccRCC patients were then categorized into high- and low-score cohorts based on the cumulative distribution curve inflection point the of risk score, which was generated by the multivariate Cox regression model. Samples from the TCGA dataset were divided into training and validation subsets to verify the prognostic risk model. Bioinformatics methods, gene set enrichment analysis, and protein–protein interaction networks, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes analyses were subsequently used.ResultsIt was found that the risk score based on 6 novel lncRNAs (CTA-384D8.35, CTD-2263F21.1, LINC01510, RP11-352G9.1, RP11-395B7.2, RP11-426C22.4) exhibited superior prognostic value for ccRCC. Moreover, we categorized the cases into two groups (high-risk and low-risk), and also examined related pathways and genetic differences between them. Kaplan–Meier curves indicated that the median survival time of patients in the high-risk group was 73.5 months, much shorter than that of the low-risk group (112.6 months; P < 0.05). Furthermore, the risk score predicted the 5-year survival of all 539 ccRCC patients (AUC at 5 years, 0.683; concordance index [C-index], 0.853; 95% CI 0.817–0.889). The training set and validation set also showed similar performance (AUC at 5 years, 0.649 and 0.681, respectively; C-index, 0.822 and 0.891; 95% CI 0.774–0.870 and 0.844–0.938).ConclusionsThe results of this study can be applied to analyzing various prognostic factors, leading to new possibilities for clinical diagnosis and prognosis of ccRCC.

Advancement on Cloud Attenuation Modelling in Tropical Ota Climatic Zone

This is a further study on development of the cloud attenuation model for improvement of the availability of satellite services in tropical Ota (6.7oN, 3.23oE) climatic zone. The radiometric data analysis has been re-evaluated for better accuracy through the Matlab embedded into the data processing electronic spreadsheets. The collection of station data such as the spectrum analyser beacon measurements of the total attenuation at re-established elevation angle 59.9° to Astra 2(E-G) satellites located at 28.2°E; the station weather parameters and the clouds parameters visual measurements; as well as the acquisition of station climatic zone radiosonde data were carried out. Then the station spectrum analyser data for 2014 - 2017 were analysed to obtain cloud attenuation contributions from the total attenuation measurement. Cloud attenuation distributions outputs of these data analyses were used to obtain the station integrated cumulative distribution for each of the existing cloud models and the 2014 – 2017 integrated data. The results at the station beacons frequency of 12.245 GHz show wide gap between the 3.40 dB maximum cloud attenuation by the Ota spectrum analyser integrated data cumulative distribution to the 0.81 dB maximum cloud attenuation predicted by its closest ITU-R model, while next in closeness is the Liebe model, followed by Slobin model. This recommends a new cloud attenuation model be developed for the tropical region. The earlier published cloud attenuation algorithm is further developed with simulation program written to run its simulations cycles over possible range of maximum signal amplitudes, using the Ota climatic zone radiosonde empirical data (1953-2011) for computations of each cloud layer’s liquid water content and specific cloud attenuation coefficient. The cumulative distribution curves obtained were compared with those for each generated simulation distribution and the closest match to the station integrated data cumulative distribution became the new cloud attenuation model for Ota climatic zone. The new model predicted 4.0 dB margin for signals to pass through clouds attenuation effect in the Ota climatic zone, revealing that the prediction for cloud attenuation by the earlier models largely under estimate the margin for the tropical region.

Measures and Distribution of Financial Inclusion in Kenya

This paper interrogates various measures and definitions of financial inclusion (FI) and their cumulative distribution in Kenya. Lack of a substantive and reliable measure of FI hampers the formulation of evidence based policy interventions. The paper presents three measures of FI founded on formal usage of; transactionary, credit, savings/investments and insurance/pension products. The first measure is focused on the use of atleast one formal financial product from each category, the second measure develops a composite measure (index of Financial Inclusion (IFI)) aggregated from the single measures and lastly a use case measure based on the needs framework. From the single product measure; transactionary, credit, savings and insurance, uptake in 2019 averaged 79 percent, 17 percent, 53 percent and 29 percent respectively. The cumulative distribution curves revealed a strong stochastic dominance by the Nairobi sub region. A ranking of the sub regions using the IFI placed Nairobi sub region on top followed by Central and Mombasa in that order. Upper Eastern, North Eastern and North Rift sub regions took the bottom three positions. The paper recommends a sustained campaign to boost the uptake of financial services from the formal strand and particularly credit and insurance whose uptake is relatively low. The study also recommends a shift from the conventional measurement of FI based on product usage to the needs based framework founded on the use case to assess efficacy of formal financial solutions to manage liquidity, mitigate risks and manage future goals. JEL Classification Numbers: C43, C81, G02, G21, G23 Keywords: Financial Inclusion, stochastic dominance, sub region DOI : 10.7176/EJBM/11-22-07 Publication date : August 31 st 2019

Detrital zircon U-Pb ages and whole-rock geochemistry of early Paleozoic metasedimentary rocks in the Mongolian Altai: Insights into the tectonic affinity of the whole Altai-Mongolian terrane

Abstract The tectonic affinity of the terranes and microcontinents within the Central Asian Orogenic Belt (CAOB) remains controversial. The Altai-Mongolian terrane (AMT), as a representative tectonic unit in the Mongolian collage, plays a vital role in reconstructing evolution history of the CAOB. The well-preserved early Paleozoic sedimentary sequence covering in this terrane could be considered as a fingerprint to track its provenance and tectonic affinity. Here, we present new whole-rock geochemistry, detrital zircon U-Pb dating, and Hf isotopic analysis for the metasedimentary rocks from the Mongolian Altai in order to shed new light on the tectonic affinity of the AMT. The youngest detrital zircon ages and the regional intrusions constrain the depositional time of the Mongolian Altai sequence to between Late Silurian and Early Devonian, which is consistent with the Habahe group in the western Chinese Altai. The features of whole-rock geochemistry and the cumulative distribution curves of the detrital zircon age spectra indicate that the Mongolian Altai sequence was probably deposited in an active continental setting during early Paleozoic. The zircon age spectra of our samples are all characterized by a main age group in the early Cambrian (peak at 541 Ma, 522 Ma, 506 Ma and 496 Ma, respectively), subdominant age populations during the Tonian, as well as rare older zircons. The nearby Lake Zone of Ikh-Mongol Arc most likely provided plenty of early Paleozoic materials, the subdominant Neoproterozoic detrital zircons could be supplied by the felsic intrusions along the western margin of the Tuva-Mongol microcontinent, and the sparse older zircons may be derived from its basement material. The Precambrian age distribution of the AMT is quite similar to both the Tarim and Siberia cratons, but the Siberia Craton displays a closer resemblance in Hf isotopic composition with the AMT. Thus, we believe that the Siberia Craton contains a closer tectonic affinity with the AMT, and that the Tuva-Mongol microcontinent possibly rifted from the western margin of this craton after the Tonian. To the south of the AMT, recent studies indicated the Yili and Central Tianshan blocks in the Kazakhstan collage of the western CAOB likely have a closer affinity with Gondwana. Therefore, the microcontinents in the CAOB most likely derived bilaterally from both the Siberia Craton and the Gondwana supercontinent. Moreover, our Hf isotopic compositions indicate two significant continental growth events in the Tonian and early Paleozoic, respectively.

Classification Method of Plug Seedlings Based on Transfer Learning

The classification of plug seedlings is important work in the replanting process. This paper proposed a classification method for plug seedlings based on transfer learning. Firstly, by extracting and graying the interest region of the original image acquired, a regional grayscale cumulative distribution curve is obtained. Calculating the number of peak points of the curve to identify the plug tray specification is then done. Secondly, the transfer learning method based on convolutional neural network is used to construct the classification model of plug seedlings. According to the growth characteristics of the seedlings, 2286 seedlings samples were collected to train the model at the two-leaf and one-heart stages. Finally, the image of the interest region is divided into cell images according to the specification of the plug tray, and the cell images are put into the classification model, thereby classifying the qualified seedling, the unqualified seedling and the lack of seedling. After testing, the identification method of the tray specification has an average accuracy of 100% for the three specifications (50 cells, 72 cells, 105 cells) of the 20-day and 25-day pepper seedlings. Seedling classification models based on the transfer learning method of four different convolutional neural networks (Alexnet, Inception-v3, Resnet-18, VGG16) are constructed and tested. The classification accuracy of the VGG16-based classification model is the best, which is 95.50%, the Alexnet-based classification model has the shortest training time, which is 6 min and 8 s. This research has certain theoretical reference significance for intelligent replanting classification work.

Fragility reduction of offshore wind turbines using tuned liquid column dampers

High flexibility of offshore wind turbines (OWTs) makes them vulnerable to excessive vibrations. This paper studies vibration control of offshore wind turbines induced by multi-hazard excitations. A model consisting of entire offshore wind turbine foundation and tower controlled by tuned liquid column dampers (TLCD) considering nonlinear soil pile interaction is established. The model is subjected to wave, wind, and seismic loading. The effect of severity of earthquake on the performance of the structural control device is investigated. A fragility analysis based on acceleration capacity thresholds is performed to estimate reliability improvement using the structural control devices. The fitted fragility functions based on multiple stripes analysis are constructed and compared with the empirical cumulative distribution curves. The results suggest that the use of an optimal TLCD with a mass ratio of 2.5% reduces the fragility of the system by as much as 6% and 12% for operational and parked conditions, respectively.

Genetic Quantitative Techniques Combined with Continuous Electromagnetic Profiling to Identify Subtle Oil and Gas Reservoirs

Subtle reservoir exploration could not be commonly carried out by costly conventional methods especially when subtle reservoirs are becoming smaller in surfaces and reserves. The epochal genetic quantitative techniques were proved to be suitable for the subtle reservoir prospecting, but the anomaly grade classification method did not match the quantitative data qualitative dividing. And the combination of genetic quantitative techniques and geophysical exploration methods to the prospecting application for subtle reservoirs still need more studies. For the questions, 194 topsoil samples and 237.05 km continuous electromagnetic profiling (CEMP) lines were arranged in typical subtle reservoirs in the Suganhu Basin. The realtime-PCR technique was used to get methanotrophic, propanotrophic functional gene pmoA and prmA quantitative data. The results showed that the classification method using cumulative probability distribution curves with regression analyses could be used to classify the genetic quantitative anomalies by the equation of y = az. The genetic quantitative anomalies and source strata thickness showed positive correlation along the section lines in the east of study areas. Integrated studies between genetic quantitative anomalies and CEMP results in the stereoscopic direction indicated three promising areas in the Suganhu Basin. This research is expected to be extended to the same type of reservoirs prospecting work.

Responses of species abundance distribution patterns to spatial scaling in subtropical secondary forests.

To quantify and assess the processes underlying community assembly and driving tree species abundance distributions(SADs) with spatial scale variation in two typical subtropical secondary forests in Dashanchong state‐owned forest farm, two 1‐ha permanent study plots (100‐m × 100‐m) were established. We selected four diversity indices including species richness, Shannon–Wiener, Simpson and Pielou, and relative importance values to quantify community assembly and biodiversity. Empirical cumulative distribution and species accumulation curves were utilized to describe the SADs of two forests communities trees. Three types of models, including statistic model (lognormal and logseries model), niche model (broken‐stick, niche preemption, and Zipf‐Mandelbrodt model), and neutral theory model, were estimated by the fitted SADs. Simulation effects were tested by Akaike's information criterion (AIC) and Kolmogorov–Smirnov test. Results found that the Fagaceae and Anacardiaceae families were their respective dominance family in the evergreen broad‐leaved and deciduous mixed communities. According to original data and random sampling predictions, the SADs were hump‐shaped for intermediate abundance classes, peaking between 8 and 32 in the evergreen broad‐leaved community, but this maximum increased with size of total sampled area size in the deciduous mixed community. All niche models could only explain SADs patterns at smaller spatial scales. However, both the neutral theory and purely statistical models were suitable for explaining the SADs for secondary forest communities when the sampling plot exceeded 40 m. The results showed the SADs indicated a clear directional trend toward convergence and similar predominating ecological processes in two typical subtropical secondary forests. The neutral process gradually replaced the niche process in importance and become the main mechanism for determining SADs of forest trees as the sampling scale expanded. Thus, we can preliminarily conclude that neutral processes had a major effect on biodiversity patterns in these two subtropical secondary forests but exclude possible contributions of other processes.