Distribution Of Increments Research Articles

Research on the Evaluation Model of Investment Economic Benefit of Incremental Power Distribution Project Under the Mode of Power Grid Effective Asset Supervision

With the development of a new round of electric power system reform, it is urgent to advance the research and formulate the transmission and distribution price reform, the distribution network project investment economic benefits post evaluation model of the incremental distribution investment liberalization. On the basis of analyzing the new requirements of the investment benefit evaluation of distribution network project, the paper constructs the life cycle economic benefit evaluation index system of the distribution project investment, including the initial investment, operation and investment, other investment, asset value and other indicators, in which effective coefficients are set up for these indicators to innovate the model.

Analyzing the posting behaviors in news forums with incremental inter-event time

Online human behaviors are widely discussed in various fields. Three key factors, named priority, interest and memory are found crucial in human behaviors. Existing research mainly focuses on the identified and active users. However, the anonymous users and the inactive ones exist widely in news forums, whose behaviors do not receive enough attention. They cannot offer abundant postings like the others. It requires us to study posting behaviors of all the users including anonymous ones, identified ones, active ones and inactive ones in news forums only at the collective level. In this paper, the memory effects of the posting behaviors in news forums are investigated at the collective level. On the basis of the incremental inter-event time, a new model is proposed to describe the posting behaviors at the collective level. The results on twelve actual news events demonstrate the good performance of our model to describe the posting behaviors at the collective level in news forums. In addition, we find the symmetric incremental inter-event time distribution and the similar posting patterns in different durations.

Space-time quantitative source apportionment of soil heavy metal concentration increments

Assessing the space-time trends and detecting the sources of heavy metal accumulation in soils have important consequences in the prevention and treatment of soil heavy metal pollution. In this study, we collected soil samples in the eastern part of the Qingshan district, Wuhan city, Hubei Province, China, during the period 2010–2014. The Cd, Cu, Pb and Zn concentrations in soils exhibited a significant accumulation during 2010–2014. The spatiotemporal Kriging technique, based on a quantitative characterization of soil heavy metal concentration variations in terms of non-separable variogram models, was employed to estimate the spatiotemporal soil heavy metal distribution in the study region. Our findings showed that the Cd, Cu, and Zn concentrations have an obvious incremental tendency from the southwestern to the central part of the study region. However, the Pb concentrations exhibited an obvious tendency from the northern part to the central part of the region. Then, spatial overlay analysis was used to obtain absolute and relative concentration increments of adjacent 1- or 5-year periods during 2010–2014. The spatial distribution of soil heavy metal concentration increments showed that the larger increments occurred in the center of the study region. Lastly, the principal component analysis combined with the multiple linear regression method were employed to quantify the source apportionment of the soil heavy metal concentration increments in the region. Our results led to the conclusion that the sources of soil heavy metal concentration increments should be ascribed to industry, agriculture and traffic. In particular, 82.5% of soil heavy metal concentration increment during 2010–2014 was ascribed to industrial/agricultural activities sources.Using STK and SOA to obtain the spatial distribution of heavy metal concentration increments in soils.Using PCA-MLR to quantify the source apportionment of soil heavy metal concentration increments.

The availability and marginal costs of dependent employer-sponsored health insurance.

In this study, we examine differences by firm size in the availability of dependent coverage and the incremental cost of such coverage. We use data from the Medical Expenditure Panel Survey - Insurance Component (MEPS-IC) to show that among employees eligible for single coverage, dependent coverage was almost always available for employees in large firms (100 or more employees) but not in smaller firms, particularly those with fewer than 10 employees. In addition, when dependent coverage was available, eligible employees in smaller firms were more likely than employees in large firms to face two situations that represented the extremes of the incremental cost distribution: (1) they paid nothing for single or family coverage or (2) they paid nothing for single coverage but faced a high contribution for family coverage. These results suggest that firm size may be an important factor in policy assessments, such as analyses of the financial implications for families excluded from subsidized Marketplace coverage due to affordable offers of single coverage or of potential rollbacks to public coverage for children.

On the impact of non-Gaussian wind statistics on wind turbines – an experimental approach

Abstract. The effect of intermittent and Gaussian inflow conditions on wind energy converters is studied experimentally. Two different flow situations were created in a wind tunnel using an active grid. Both flows exhibit nearly equal mean velocity values and turbulence intensities but strongly differ in their two point statistics, namely their distribution of velocity increments on a variety of timescales, one being Gaussian distributed, and the other one being strongly intermittent. A horizontal axis model wind turbine is exposed to both flows, isolating the effect on the turbine of the differences not captured by mean values and turbulence intensities. Thrust, torque and power data were recorded and analyzed, showing that the model turbine does not smooth out intermittency. Intermittent inflow is converted to similarly intermittent turbine data on all scales considered, reaching down to sub-rotor scales in space. This indicates that it is not correct to assume a smoothing of intermittent wind speed increments below the size of the rotor.

Value-at-Risk Calculations with Time Varying Copulae

Value-at-Risk (VaR) of a portfolio is determined by the multivariate distribution of the risk factors increments. This distribution can be modelled through copulae, where the copulae parameters are not necessarily constant over time. For an exchange rate portfolio, copulae with time varying parameters are estimated and the VaR simulated accordingly. Backtesting underlines the improved performance of time varying copulae.

Scalar gradients in stirred mixtures and the deconstruction of random fields

A general theory for predicting the distribution of scalar gradients (or concentration differences) in heterogeneous flows is proposed. The evolution of scalar fields is quantified from the analysis of the evolution of elementary lamellar structures, which naturally form under the stretching action of the flows. Spatial correlations in scalar fields, and concentration gradients, hence develop through diffusive aggregation of stretched lamellae. Concentration levels at neighbouring spatial locations result from a history of lamella aggregation, which is partly common to the two locations. Concentration differences eliminate this common part, and thus depend only on lamellae that have aggregated independently. Using this principle, we propose a theory which envisions concentration increments as the result of a deconstruction of the basic lamella assemblage. This framework provides analytical expressions for concentration increment probability density functions (PDFs) over any spatial increments for a range of flow systems, including turbulent flows and low-Reynolds-number porous media flows, for confined and dispersing mixtures. Through this deconstruction principle, scalar increment distributions reveal the elementary stretching and aggregation mechanisms building scalar fields.

INTERNATIONAL RESERVE MANAGEMENT: A DRIFT‐SWITCHING REFLECTED JUMP‐DIFFUSION MODEL

AbstractWe study the cost of shocks, that is, jump risk, with respect to reserve management when the reserve process is formulated as a drift‐switching jump diffusion with a reflecting barrier at 0. Inspired by the Brownian drift switching model, our model results in a more realistic dynamic behavior of international reserves than the buffer stock model. The new model can capture both the jump behavior in reserve dynamics and the leptokurtic feature of the increment distribution which has a higher peak and two asymmetric heavier tails than the normal distribution. Through the selection of an initial distribution that reflects certain steady state behaviors, the reserve process becomes a regenerative process. This selection enables us to derive a closed‐form expression for the total expected discounted cost of managing reserves, thus helping us to numerically find management strategies that minimize costs. The numerical results show that shocks at the reserve level have a significant effect on reserve management strategies and that model misspecification can result in nonnegligible additional costs.

Spectral structure of 5 year time series of horizontal wind speed at the Boulder Atmospheric Observatory

AbstractWe investigate the spectral structures of 5 year, 1 min time series of horizontal wind speeds at 100 and 10 m heights at the Boulder Atmospheric Observatory tower located in the eastern slope of the Rocky Mountains, USA. In the full‐scale spectra, the diurnal spectral peak, which is usually insignificant at a coastal or offshore site, is the most significant at both heights. The spectrum is enhanced on the low‐frequency side of the diurnal peak during winter, but on the high‐frequency side during summer, which indicates frequent synoptic weather events during winter supplanted by mesoscale events during summer. In terms of the spectral density in the spectral gap of Van der Hoven (1957), separating boundary layer turbulence from the synoptic‐scale fluctuations, at a frequency between 10−4 and 10−3 Hz, we rank the daily time series at 100 m height and sample the summer top and winter bottom 10 percentile cases. The winter cases of the reduced spectral density in the gap region present the f−3 spectrum (f is frequency) and negatively skewed velocity increment distributions, which are the signatures of enstrophy (the integral of squared vorticity) cascade of turbulent two‐dimensional (2‐D) flows. In contrast, the summer cases of the enhanced spectral density present the f−5/3 spectrum and positively skewed velocity increment distributions, which are the signatures of upscale energy cascade of 2‐D flows. In these mesoscale events that fill up the gap, the turbulence intensity‐wind speed relationship is very sensitive to the choice of the averaging period.

Compressive tracking with incremental multivariate Gaussian distribution

Various approaches have been proposed for robust visual tracking, among which compressive tracking (CT) yields promising performance. In CT, Haar-like features are efficiently extracted with a very sparse measurement matrix and modeled as an online updated naive Bayes classifier to account for target appearance change. The naive Bayes classifier ignores overlap between Haar-like features and assumes that Haar-like features are independently distributed, which leads to drift in complex scenario. To address this problem, we present an extended CT algorithm, which assumes that all Haar-like features are correlated with each other and have multivariate Gaussian distribution. The mean vector and covariance matrix of multivariate normal distribution are incrementally updated with constant computational complexity to adapt to target appearance change. Each frame is associated with a temporal weight to expend less modeling power on old observation. Based on temporal weight, an update scheme with changing but convergent learning rate is derived with strict mathematic proof. Compared with CT, our extended algorithm achieves a richer representation of target appearance. The incremental multivariate Gaussian distribution is integrated into the particle filter framework to achieve better tracking performance. Extensive experiments on the CVPR2013 tracking benchmark demonstrate that our proposed tracker achieves superior performance both qualitatively and quantitatively over several state-of-the-art trackers.

Experimental study of ultra-large capacity end-plate joints

When bolted joints are required in steel structures involving large spans or heavy loads, ultra-large capacity end-plate joints with 12 bolts or 16 bolts in tension should be applied if ordinary end-plate joints or large capacity end-plate joints cannot meet the resistance requirement. Four full-scale specimens of ultra-large capacity end-plate joints were tested subjected to monotonic load. The moment-rotation curves of all the specimens were obtained, and the moment resistance, rotational stiffness, and distribution of the bolt strain increments in tension were analyzed when the bolt diameter, the end-plate thickness, or the layout of the bolts changed. The tested ultra-large capacity end-plate joints shared the failure mode of end-plate yielding followed by bolt fracture or necking, and the thickness of the end plate had an obvious influence on the joint resistance. A significantly inhomogeneous distribution of bolt strain increments was observed. Bolts in corners, which made little contribution to the moment resistance in the tests, could be removed or considered as shear-resistant bolts. In the design of this kind of joint, the resistance of the panel zone can be decided according to the Chinese code, the American code, or the Eurocode, and the equivalent number of the bolts in tension is recommended to be 7.0 based on a proposed distribution model of the tension load resisted by bolts in tension, derived from the tests.

Exact Statistics of Record Increments of Random Walks and Lévy Flights.

We study the statistics of increments in record values in a time series {x_{0}=0,x_{1},x_{2},…,x_{n}} generated by the positions of a random walk (discrete time, continuous space) of duration n steps. For arbitrary jump length distribution, including Lévy flights, we show that the distribution of the record increment becomes stationary, i.e., independent of n for large n, and compute it explicitly for a wide class of jump distributions. In addition, we compute exactly the probability Q(n) that the record increments decrease monotonically up to step n. Remarkably, Q(n) is universal (i.e., independent of the jump distribution) for each n, decaying as Q(n)∼A/sqrt[n] for large n, with a universal amplitude A=e/sqrt[π]=1.53362….

A Simulation-Based Study on Bayesian Estimators for the Skew Brownian Motion

In analyzing a temporal data set from a continuous variable, diffusion processes can be suitable under certain conditions, depending on the distribution of increments. We are interested in processes where a semi-permeable barrier splits the state space, producing a skewed diffusion that can have different rates on each side. In this work, the asymptotic behavior of some Bayesian inferences for this class of processes is discussed and validated through simulations. As an application, we model the location of South American sea lions (Otaria flavescens) on the coast of Calbuco, southern Chile, which can be used to understand how the foraging behavior of apex predators varies temporally and spatially.

A measure of scale-dependent asymmetry in turbulent boundary layer flows: scaling and Reynolds number similarity

The distribution of temporal scale-dependent streamwise velocity increments is investigated in turbulent boundary layer flows at laboratory and atmospheric Reynolds numbers, using the St. Anthony Falls Laboratory wind tunnel and the Surface Layer Turbulence and Environmental Science Test dataset, respectively. The third-order moments of velocity increments, or asymmetry index $A(a,z)$, is computed for varying wall distance $z$ and time scale separation $a$, where it was observed to leave a robust, distinct signature in the form of a hump, independent of Reynolds number and located across the inertial range. The hump is observed in wall region limited to $z^{+}<5\times 10^{3}$, with a tendency to shift towards smaller time scales as the surface is approached ($z^{+}<70$). Comparing the two datasets, the hump, and its location, are found to obey inner wall scaling and is regarded as a genuine feature of the canonical turbulent boundary layer. The magnitude cumulant analysis of the scale-dependent velocity increments further reveals that intermittency is also enhanced near the wall, in the same flow region where the asymmetry signature was observed. The combination of asymmetry and intermittency is inferred to point at non-local energy transfer and scale coupling across a range of scales. From a turbulent structure perspective, such non-local energy transfer can be seen as the result of strong scale-interaction processes between outer scale motions in the logarithmic layer impacting and distorting smaller scales at the wall, through abrupt energy transfer across scales bypassing the typical energy cascade of the inertial range.

Does diameter increment of Lebanon oak trees (Quercus libani Oliv.) affected by pollarding in Northern Zagros, Iran?

Lebanon oak is one of the important oak species in the Northern Zagros forests, west of Iran, which exposed to severe pollarding in traditional silvopastoral management. The purpose of this study was to investigate the effect of pollarding on diameter increment of Lebanon oak trees. Therefore, a less-disturbed stand (0.7 ha) and a pollarded stand (1 ha) with similar physiographical conditions were selected. Full Callipering was performed in both stands and tree species; collar diameter and crown diameter for all trees (collar diameter ≥5 cm) were recorded. Moreover, total and trunk heights were measured in Lebanon oak trees as well. To evaluate the diameter increment of Lebanon oak trees, 20 and 15 tree samples were taken in the less-disturbed and pollarded stands, respectively. A pair of increment cores per sample tree was taken 100 cm above ground level, using increment borer. In the cores, annual radial increment was measured and the annual diameter increment was calculated by doubling that value. The diameter increment distribution of Lebanon oak trees in identical age classes was determined and used for comparison. The results indicated that the difference of the mean diameter increment of Lebanon oak in the same diameter classes was significant (P < 0.05) between two stands. The mean diameter increment in age classes of 57–81 years (P < 0.01) was significantly different (P < 0.01) between the two studied stands; however, in the age classes of 1–55 years, there was no significant difference (P = 0.559).

Variational data assimilation for the optimized ozone initial state and the short-time forecasting

Abstract. In this study, we apply the four-dimensional variational (4D-Var) data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation are analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12 h assimilation periods and the 120 observatory sites show a 49.4 % decrease in the root mean squared error (RMSE), and a 59.9 % increase in the index of agreement (IOA). The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE (root mean squared error) with assimilation versus that without assimilation are 8 and 13 % for the +24 and +12 h, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential improvement in ozone prediction for both the daytime and nighttime with application of data assimilation is also presented.

Kinematic 3-D Retro-Modeling of an Orogenic Bend in the South Limón Fold-and-Thrust Belt, Eastern Costa Rica: Prediction of the Incremental Internal Strain Distribution

The South Limon fold-and-thrust belt, in the back-arc area of southern Costa Rica, is characterized by a 90° curvature of the strike of the thrust planes and is therefore a natural laboratory for the analysis of curved orogens. The analysis of curved fold-and-thrust belts is a challenge because of the varying structural orientations within the belt. Based on seismic reflection lines, we created a 3-D subsurface model containing three major thrust faults and three stratigraphic horizons. 3-D kinematic retro-deformation modeling was carried out to analyze the spatial evolution of the fold-and-thrust belt. The maximum amount of displacement on each of the faults is (from hinterland to foreland); thrust 1: 800 m; thrust 2: 600 m; thrust 3: 250 m. The model was restored sequentially to its pre-deformational state. The strain history of the stratigraphic horizons in the model was calculated at every step. This shows that the internal strain pattern has an abrupt change at the orogenic bend. Contractional strain occurs in the forelimbs of the hanging-wall anticlines, while a zone of dilative strain spreads from the anticline crests to the backlimbs. The modeling shows that a NNE-directed transport direction best explains the structural evolution of the bend. This would require a left-lateral strike-slip zone in the North to compensate for the movement and thereby decoupling the South Limon fold-and-thrust belt from northern Costa Rica. Therefore, our modeling supports the presence of the Trans-Isthmic fault system, at least during the Plio-Pleistocene.

BMI and BMI SDS in childhood: annual increments and conditional change

Background Early detection of abnormal weight gain in childhood may be important for preventive purposes. It is still debated which annual changes in BMI should warrant attention.Aim To analyse 1-year increments of Body Mass Index (BMI) and standardised BMI (BMI SDS) in childhood and explore conditional change in BMI SDS as an alternative method to evaluate 1-year changes in BMI.Subjects and methods The distributions of 1-year increments of BMI (kg/m2) and BMI SDS are summarised by percentiles. Differences according to sex, age, height, weight, initial BMI and weight status on the BMI and BMI SDS increments were assessed with multiple linear regression. Conditional change in BMI SDS was based on the correlation between annual BMI measurements converted to SDS.Results BMI increments depended significantly on sex, height, weight and initial BMI. Changes in BMI SDS depended significantly only on the initial BMI SDS. The distribution of conditional change in BMI SDS using a two-correlation model was close to normal (mean = 0.11, SD = 1.02, n = 1167), with 3.2% (2.3–4.4%) of the observations below −2 SD and 2.8% (2.0–4.0%) above +2 SD.Conclusion Conditional change in BMI SDS can be used to detect unexpected large changes in BMI SDS. Although this method requires the use of a computer, it may be clinically useful to detect aberrant weight development.

Large Deviation Principles for Trajectories of Compound Renewal Processes. I

The present paper continues studies of large deviation principles for compound renewal processes that were started in [A. A. Borovkov, Asymptotic Analysis of Random Walking. Fast Decreasing Increment Distributions, Fizmatlit, Moscow, 2013 (in Russian)], [A. A. Borovkov and A. A. Mogul'skii, Siberian Math. J., 56 (2015), pp. 28--53]. The main subject of this research is probabilities of large deviations of the trajectories of compound renewal processes. The paper consists of two parts. In part I, under some condition on the distribution of the process, we obtain the so-called first partial local large deviation principle for the trajectories of a compound renewal process. In part II, under an alternative condition, we obtain the second partial local large deviation principle. Under additional conditions, we also obtain the “total local” and “total integral” large deviation principles for compound renewal processes.

Quantifying non-stationarity effects on organization of atmospheric turbulent eddy motion by Benford's law

How to quantify the effects of non-stationarity on organization of atmospheric turbulent eddy motions has drawn less attention in recent literatures. Here Benford's law (BL), which states that the first digit (1 through 9) in many datasets follows a monotonically decreasing logarithmic distribution, is used to address this issue for the first time. A quantifier called multi-scale first digit entropy (MFDE) is adopted, which is based on the deviation of BL from the practical first digit distribution of multi-scaled vertical velocity increments, and marked differences are detected in stationary and non-stationary series. The MFDE values of stationary records do not change much with different scales while increase significantly for non-stationary ones as time scales increase. Due to the close relationship between MFDE and the multi-scale Shannon entropy (MSSE), the above results indicate that the non-stationary series are more organized than the stationary ones. Especially, the MFDE can also be used to quantify the different organization degrees of the multi-scaled structures existing in surface vertical velocity records.