Linear Moment Research Articles

A Novel High-Order Surface Characteristics Scheme for the Neutron Transport Equation in 2D Unstructured Meshes

The development of higher-order method of characteristics (MOC) discretizations has become of great interest to improve the performance of solvers based on the standard Stepwise Constant (SC) MOC approximation. Many codes nowadays implement a Stepwise Linear (SL) volume flux approximation or diamond differencing schemes. In the multigroup lattice solver TDT of the industrial code APOLLO3®, developed at CEA, a Linear Surface (LS) scheme was implemented. In this method, the flux is reconstructed from a linear interpolation made from surface values, therefore ensuring a similar spatial linear development but with a lower computational cost than the volume-based approximations. However, the LS-MOC scheme can conserve only the constant spatial moment of the flux. To overcome this limitation, in this paper we propose an improved version of the LS scheme called LS- xy able to preserve the linear spatial moments of the flux. Compared to the other high-order volume-based approximations, the LS- xy scheme also preserves flux surface moments, which guarantees higher accuracy. Moreover, our scheme has a lower memory footprint because it does not require the storage of response matrices that are dependent on region, group, and anisotropy order. Tests carried out on severe rodded assembly cases show the superior performance of the proposed method with respect to not only the classic SC or LS MOC scheme but also the SL scheme.

Derivation of long duration geographically-centred areal reduction factors for catchment design rainfall estimation in South Africa

Study regionSouth Africa. Study focusThe use of Areal Reduction Factors (ARFs) to convert average design point rainfall into areal catchment design rainfall is regarded as fundamental input to event-based deterministic design flood estimation methods. The ARF methods currently used in South Africa are outdated and were neither developed nor verified using local data. This paper presents the development and assessment of a regionalised approach to estimate long duration (≥ 1-day) geographically-centred ARFs using daily rainfall data representative of the 78 homogeneous long duration rainfall clusters associated with the Regional Linear Moment Algorithm and Scale Invariance (RLMA&SI) regionalisation scheme in South Africa. In order to meet the recommended World Meteorological Organisation rainfall station density criteria, the latter clusters were merged into 46 clusters. Subsequently, long duration geographically-centred sample ARFs were estimated using 2 053 circular catchments and 1 779 daily rainfall stations. New hydrological insights for the regionFive ARF regions were deduced from the 46 clusters and a single regional empirical ARF equation, with unique regional calibration coefficients, was derived. The ARF methodology developed and the subsequent findings are not only new to the South African flood hydrology community and practice, but are also probabilistically correct given that the ARF estimates decrease with an increasing catchment area and decrease with a decreasing storm duration and return period, unlike many other methods used internationally.

Two-Parameter Probability Distributions: Methods, Techniques and Comparative Analysis

Considering the wide applicability of two-parameter distributions in the frequency analysis of extreme events, this article presents new elements regarding the use of thirteen two-parameter probability distributions, using three parameter estimation methods. All the necessary elements for the application of these distributions are presented using the method of ordinary moments (MOM), the method of linear moments (L-moments) and the method of high order linear moments (LH-moments). Only these three methods are analyzed, because they are usually applied in the analysis regarding the regionalization of extreme events. As a case study, the frequency analysis of the maximum annual flows on the Siret River, Lungoci station, Romania, was made. For the recommended methods (L- and LH-moments), from the thirteen analyzed distributions, the log-normal distribution had the best results, with the theoretical values L-coefficient of variation and L-kurtosis (0.297, 0.192, 0.323, 0.185, 0.336, and 0.185) best approximating the corresponding values of the recorded data (0.339, 0.185, 0.233, 0.199, 0.198, and 0.205).

Impact of Fraud Risk Management and Sustainability of Small and Medium Enterprises in Abuja, Nigeria

Purpose: The purpose of this study are to: to assess the effect of fraud risk Management and the sustainability of SMEs in Nigeria; to find out whether there exist relationship between employee’s education and anti-fraud programs among SMEs in Abuja Metropolis, Nigeria; to examine whether there exist relationship between SMEs in Abuja metropolis and anonymous way of reporting suspected violations of the ethics and anti-fraud programs; and to investigate the nature of relationship between fraud incidents and SMEs in Abuja Metropolis, Nigeria. Methodology: The study made use of survey research design and regression and correlation analysis was used to test the hypotheses raised. The study made use of survey research design and regression and correlation analysis was used to test the hypotheses raised. Theoretical Framework: this study adopted the model of Carter & Rodgers (2008) which was designed on the basis for organisation to move from a separate thrive to achieve sustainability to a more collaborative approach. Findings: Thus, the hypotheses of the study were specified in their null form and were tested using multiple linear regression model and Pearson Product Moment Correlation Analysis. The results of the test were evaluated at 5 percent level. After evaluation of the hypotheses, the findings show that Fraud risk Management has significant effect on the sustainability of SMEs in Abuja Metropolis, Nigeria, the present fraud risk management is effective for the sustainability, effective fraud risk management is key for the survival of my SME, and SMEs in Abuja Metropolis are working in compliance with fraud policies, there is a significant positive relationship between employee’s education and anti-fraud programs among SMEs in Abuja Metropolis, Nigeria, there is a strong positive relationship between education of employees on the importance of ethics and anti-fraud programs and provision of anonymous way to report suspected violations by SMEs. Education of employee has positive and significant relationship with fraud incident among SMEs in Abuja Metropolis, there is no significant relationship between SMEs in Abuja metropolis and anonymous way of reporting suspected violations of the ethics and anti-fraud programs. Conclusion: There is significant relationship between fraud incidents and SMEs in Abuja Metropolis, Nigeria. The therefore recommends that efforts should be made to educate SMEs on how to tackle fraud related risk and SMEs should endavour to share ideas among themselves to enable them properly manage fraud risk.

ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ РОЗПОДІЛЬНИХ МЕРЕЖ РАЙОНІВ МАЛОПОВЕРХОВОЇ ЗАБУДОВИ МІСТ

The article analyzes the methods of estimating the parameters and regimes of electrical distribution networks in areas of low-rise urban development. A method for optimizing the parameters of distribution networks of 0.38 kV under conditions of uncertainty of the initial information is proposed. It is shown that one of the unsolved problems of calculating the parameters of distribution electric networks of cities is the determination of the estimated load of utility consumers. Its dependence on the characteristics of consumers and their number connected to the lines of city transformer substations causes the low accuracy of calculations. In this case, the error of calculating the transformer substations load can reach 10-25%, and the error of calculating the cross-sections of 0.38 kV lines reaches 40%. In the assumption of the constancy of the total length of the lines of urban electric networks and the invariance of the distance between loads, calculation formulas for linear moments and load distribution coefficients are proposed, and based on them, models of intersection and power losses in lines are developed. Taking into account the developed models, we offer discounted cost models for 0.38 kV networks and transformer substations when calculating economic current density and allowable voltage costs. Keywords: optimization, distribution networks, uncertainty, efficiency, low-rise building, scheme.

A sensitivity analysis framework for SMA-based self-centering systems considering uncertainty in hysteretic material parameters

Shape memory alloys (SMAs) are widely utilized as the core component to develop self-centering (SC) structures owing to their excellent super-elasticity. Seismic performance of SMA-based structures is significantly influenced by the hysteretic parameters of the exploited SMAs. Uncertainties in the hysteretic parameters of SMAs could cause variation in seismic performance however have not received sufficient attentions. This paper proposes a sensitivity analysis framework to realistically and efficiently quantify the sensitivity of SMA-based structures to hysteretic model parameters. The experimental data from SMA bars are analyzed through the Markov chain Monte Carlo (MCMC) procedure. The probabilistic distributions of SMA hysteretic parameters are then sampled using the linear moment theory. Polynomial chaos expansions (PCE) based surrogate model is then used to evaluate sensitivity of response to different parametric uncertainties through the Sobol indices. The proposed framework is then applied to a total of 120 single-degree-of-freedom (SDOF) systems to demonstrate its efficacy to generalize observations and findings. The results show that the proposed framework provided more effective and realistic sensitivity analysis of seismic responses of SMA-based SDOF systems to account for uncertainty in the hysteretic model parameters. The Sobol indices also indicate that the sensitivity of different seismic response quantities varies for different hysteretic model parameters of SMAs.

Quantification of material modeling uncertainty on seismic performance of SMA-based self-centering concentrically braced frames

Shape memory alloys (SMAs) combine super-elasticity and energy dissipation capacity therefore is favored in seismic hazard mitigation. Simplifications are necessary to incorporate acquired material properties through material testing for dynamic analysis. This study presents a methodology to integrate SMA material testing, model inference, and probabilistic seismic analysis for uncertainty quantification of SMA model uncertainty on SMA based structures. The proposed methodology is applied to a SMA-based self-centering concentrically braced frame (SC-CBF). The posterior distribution of SMA modeling parameters is first obtained through the MCMC algorithm. Considering computational cost of MCMC algorithm, linear moments method is introduced to sample SMA modeling parameters. Extensive time-history analysis is then performed to quantify the effect of SMA modelling uncertainty and ground motions on the performance of SC-CBF. Significant response changes can be observed in SC-CBF due to the effect of uncertainty, which inevitably affect the reliability assessment of the structure. These analysis results also show that modeling uncertainty will affect seismic performance of SMA-based SC-CBF but its influence is less significant than that caused by ground motion uncertainty for the braced frame investigated in this study.

Extreme Events Analysis Using LH-Moments Method and Quantile Function Family

A direct way to estimate the likelihood and magnitude of extreme events is frequency analysis. This analysis is based on historical data and assumptions of stationarity, and is carried out with the help of probability distributions and different methods of estimating their parameters. Thus, this article presents all the relations necessary to estimate the parameters with the LH-moments method for the family of distributions defined only by the quantile function, namely, the Wakeby distribution of 4 and 5 parameters, the Lambda distribution of 4 and 5 parameters, and the Davis distribution. The LH-moments method is a method commonly used in flood frequency analysis, and it uses the annual series of maximum flows. The frequency characteristics of the two analyzed methods, which are both involved in expressing the distributions used in the first two linear moments, as well as in determining the confidence interval, are presented. The performances of the analyzed distributions and the two presented methods are verified in the following maximum flows, with the Bahna river used as a case study. The results are presented in comparison with the L-moments method. Following the results obtained, the Wakeby and Lambda distributions have the best performances, and the LH-skewness and LH-kurtosis statistical indicators best model the indicators’ values of the sample (0.5769, 0.3781, 0.548 and 0.3451). Similar to the L-moments method, this represents the main selection criterion of the best fit distribution.

Pengaruh loyalitas pengguna aplikasi iPusnas di kalangan mahasiswa Diploma 3 Perpustakaan FKIP Universitas Tanjungpura terhadap minat membaca buku digital

This research was conducted to determine the level of loyalty and interest in reading digital books among Diploma 3 students of the FKIP Library of Tanjungpura University and to determine the effect of loyalty on interest in reading digital books among Diploma 3 students of the FKIP Library of Tanjungpura University. This study uses a quantitative approach so that the data collected can be processed specifically. The population in the study amounted to 58 people, namely all active students in the environment of the Diploma 3 Library study program at FKIP Tanjungpura University. The sample was selected using saturated sampling technique or cencus. Data collection in this study was by semi-structured interviews and then followed by distributing questionnaires to the sample. Value measurement on data results using a Likert scale. The validity test used 30 samples using the Pearson Correlation method. The data analysis technique uses the mean formula followed by the grand mean formula from the overall average. While hypothesis testing is done with simple linear regression tests and product moment correlation tests. The research shows the results that iPusnas application user loyalty has a positive and significant impact on interest in reading digital books

Modeling IP[formula omitted]-induced Ca[formula omitted] signaling based on its interspike interval statistics

Inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ signaling is a second messenger system used by almost all eukaryotic cells. Recent research demonstrated randomness of Ca2+ signaling on all structural levels. We compile eight general properties of Ca2+ spiking common to all cell types investigated and suggest a theory of Ca2+ spiking starting from the random behavior of IP3 receptor channel clusters mediating the release of Ca2+ from the endoplasmic reticulum capturing all general properties and pathway-specific behavior. Spike generation begins after the absolute refractory period of the previous spike. According to its hierarchical spreading from initiating channel openings to cell level, we describe it as a first passage process from none to all clusters open while the cell recovers from the inhibition which terminated the previous spike. Our theory reproduces the exponential stimulation response relation of the average interspike interval Tav and its robustness properties, random spike timing with a linear moment relation between Tav and the interspike interval SD and its robustness properties, sensitive dependency of Tav on diffusion properties, and nonoscillatory local dynamics. We explain large cell variability of Tav observed in experiments by variability of channel cluster coupling by Ca2+-induced Ca2+ release, the number of clusters, and IP3 pathway component expression levels. We predict the relation between puff probability and agonist concentration and [IP3] and agonist concentration. Differences of spike behavior between cell types and stimulating agonists are explained by the different types of negative feedback terminating spikes. In summary, the hierarchical random character of spike generation explains all of the identified general properties.

Female cricket pace bowling: kinematic and anthropometric relationships with ball release speed.

Despite an increase in the professionalism and participation of female cricket, the coaching of female pace bowling is still reliant on male-derived knowledge. To investigate the association between key male-derived kinematic and anthropometric parameters and ball release speed (BRS) in female pace bowlers. Eleven female pace bowlers participated in this study. BRS, and four anthropometric and five kinematic parameters were determined. Stepwise linear regression and Pearson Product Moment correlations were used to identify anthropometric and kinematic parameters linked to BRS. The best predictor of BRS explaining 89% of the observed variance was the bowling shoulder angle at ball release. The best anthropometric predictor of BRS was height explaining 53% of the observed variance. Other parameters correlated with BRS included: run-up speed (r = 0.75, p = 0.013) and arm length (r = 0.61, p = 0.046). When height was controlled for, the front knee angle at front foot contact was also correlated to BRS (r = 0.68, p = 0.044). No relationship was found between trunk flexion and BRS. Faster BRS were characterised by faster run-up speeds, straighter front knees, and delayed arm circumduction similar to male pace bowlers. The lack of relationship between trunk flexion and BRS may highlight female pace bowlers adopting a bowling technique where BRS is contributed to by trunk rotation as well as trunk flexion. This knowledge is likely to be useful in the talent identification and coaching of female pace bowlers.

Linear Moment Models to Approximate Knudsen Layers

We propose a well-posed Maxwell-type boundary condition for the linear moment system in half-space. As a reduction of the Boltzmann equation, the moment equations are available to model Knudsen layers near a solid wall, where proper boundary conditions should be prescribed. Utilizing an orthogonal decomposition, we separate the part with a damping term from the system and then impose a new class of Maxwell-type boundary conditions on it. Due to the new boundary condition, we show that the half-space boundary value problem admits a unique solution with explicit expressions. Instantly, the well-posedness of the linear moment system is achieved. We apply the procedure to classical flow problems with the Shakhov collision term, such as the velocity slip and temperature jump problems. The model can capture Knudsen layers with very high accuracy using only a few moments.

Predicting Flood Frequency with the LH-Moments Method: A Case Study of Prigor River, Romania

The higher-order linear moments (LH-moments) method is one of the most commonly used methods for estimating the parameters of probability distributions in flood frequency analysis without sample censoring. This article presents the relationships necessary to estimate the parameters for eight probability distributions used in flood frequency analysis. Eight probability distributions of three parameters using first- and second-order LH-moments are presented, namely the Pearson V distribution, the CHI distribution, the inverse CHI distribution, the Wilson–Hilferty distribution, the Pseudo-Weibull distribution, the Log-normal distribution, the generalized Pareto Type I distribution and the Fréchet distribution. The exact and approximate relations for parameter estimation are presented, as are the exact and approximate relations for estimating the frequency factor specific to each method. In addition, the exact and approximate relationships of variation in the LH-skewness–LH-kurtosis are presented, as is the variation diagram of these statistical indicators. To numerically represent the analyzed distributions, a flood frequency analysis case study using the annual maximum series was carried out for the Prigor River. The analysis is presented compared to the linear moments (L-moments) method, which is the method that is intended to be used in the development of a new norm in Romania for determining the maximum flows. For the Prigor River, the most fit distributions are the Pseudo-Weibull and the generalized Pareto Type I for the linear moments method and the CHI and the Wilson–Hilferty distributions for the first higher-order linear moments method. The performance was evaluated using linear and higher-order linear moment values and diagrams.

Simple Inference on Functionals of Set-Identified Parameters Defined by Linear Moments

This article proposes a new approach to obtain uniformly valid inference for linear functionals or scalar subvectors of a partially identified parameter defined by linear moment inequalities. The procedure amounts to bootstrapping the value functions of randomly perturbed linear programming problems, and does not require the researcher to grid over the parameter space. The low-level conditions for uniform validity rely on genericity results for linear programs. The unconventional perturbation approach produces a confidence set with a coverage probability of 1 over the identified set, but obtains exact coverage on an outer set, is valid under weak assumptions, and is computationally simple to implement.

L-Moments-Based FORM Method for Structural Reliability Analysis Considering Correlated Input Random Variables

Leveraging the properties of the first three linear moments (L-moments), this study proposes an effective normal transformation for structural reliability analysis considering correlated input random variables, in which the admissible range of the initial correlation matrix when employing this transformation is also presented. Subsequently, a practical procedure for structural reliability analysis, grounded in the proposed transformation and first-order reliability method (FROM), is proposed, accommodating instances wherein the joint probability density functions (PDFs) or marginal PDFs of the relevant random variables remain unknown. In comparison to the technique premised on the first three central moments (C-moments), the proposed method, based on the first three L-moments, exhibits a more extensive applicability. Various practical scenarios showcase the method’s effectiveness and precision in calculating the structural reliability index, considering diverse distributions, numerous variables, and complex structures.

Theoretical insight on the charge transport properties: The formation of "head-to-tail" and "head-to-head" stacking of asymmetric aryl anthracene derivatives.

Organic semiconductors (OSCs) are widely used in flexible display, renewable energy, and biosensors, owing to their unique solid-state physical and optoelectronic properties. Among the abundant crystal library of OSCs, asymmetric aryl anthracene derivatives have irreplaceable advantages due to the interplay between their distinct π-conjugated geometry and molecular stacking as well as efficient light emission and charge transport properties that can be simultaneously utilized. However, the poor crystal stacking patterns of most asymmetric molecules limit their utility as excellent OSCs. Thus, it is crucial to clarify the structural features that enable the extremely ordered stacking and favorable electronic structure of asymmetric anthracene derivatives to become high-performance OSCs. This contribution investigates the charge transport properties of a series of asymmetric aryl anthracene derivatives to reveal the modulation factors of the molecular stacking modes and to explore the structural factors, which are beneficial to charge transport. The analysis demonstrated that the vinyl-linker facilitated the injection of hole carriers, and the alkynyl-linker effectively reduces the reorganization energy. Importantly, the linear polarizability and permanent dipole moment of a single molecule play a vital regulation to molecular stacking modes and the transfer integral of the dimer. The "head-to-head stacking" motif shows a compact stacking pattern and the maximum 2D anisotropic mobility more than 10cm2V-1s-1. These findings sharpen our understanding of the charge transport properties in asymmetric organic semiconductors and are essential for developing a diverse range of high-performance OSC materials.

Accounting information in improving corporate values and responsibility to stakeholders in cement manufacturing companies in Indonesia

The study looked at manufacturing cement as an object of research. Reasons why the cement industry go the public is: 1). Manufacturing companies Cement is still very little that goes public in Indonesian; 2). Cost of goods calculation production at more manufacturing companies complex when compared to service companies. The purpose of this study is to determine the effect of cost accounting information on the improvement of corporate value and responsibility to stakeholders, in the cement industry companies listed in Indonesia Stock Exchange (BEI) period 2017-2022. Data analysis techniques using simple linear regression analysis product correlation moment for causality test and comparative analysis k one way ANOVA independent sample for comparative test, with 5% significance level. The results showed that the cost accounting information, which is realized in the calculation of cost of goods manufactured significantly affects the increase of company value. Increased corporate value significantly influences the company's ability to fulfill its responsibilities to stakeholders, such as paying dividends to shareholders, borrowing interest expenses to creditors, hiring employees, and paying taxes to the government. This study also concludes that there are differences in firm size, dividend payout, tax burden, interest expense on cement the company goes public in Indonesia, while the salary load is not significantly different.

Evaluation of Various Generalized Pareto Probability Distributions for Flood Frequency Analysis

This article analyzes six probability distributions from the Generalized Pareto family, with three, four and five parameters, with the main purpose of identifying other distributions from this family with applicability in flood frequency analysis compared to the distribution already used in the literature from this family such as Generalized Pareto Type II and Wakeby. This analysis is part of a larger and more complex research carried out in the Faculty of Hydrotechnics regarding the elaboration of a norm for flood frequency analysis using the linear moments method. In Romania, the standard method of parameter estimation is the method of ordinary moments, thus the transition from this method to the method of linear moments is desired. All the necessary elements for the distribution use are presented, such as the probability density functions, the complementary cumulative distribution functions, the quantile functions, and the exact and approximate relations for estimating parameters, for both methods of parameter estimation. All these elements are necessary for a proper transition between the two methods, especially since the use of the method of ordinary moments is done by choosing the skewness of the observed data depending on the origin of the maximum flows. A flood frequency analysis case study, using annual maximum and annual exceedance series, was carried out for the Prigor River to numerically present the analyzed distributions. The performance of this distribution is evaluated using a linear moments diagram.

Kontribusi Data Akuntansi Biaya terhadap Peningkatan Nilai Perusahaan dan Tanggung Jawab Pemangku Kepentingan pada Perusahaan Manufaktur Semen Indonesia

Introduction: The purpose of this study is to determine the effect of cost accounting information on the improvement of corporate value and responsibility to stakeholders, at cement industry companies listed in Indonesia Stock Exchange (BEI) period 2016-2021. Research Methods: Data analysis techniques using simple linear regression analysis product correlation moment for causality test and comparative analysis k one way ANOVA independent sample for comparative test, with 5% significance level. Results: The results showed that the cost accounting information, which is realized in the calculation of cost of goods manufactured, has a significant effect on the increase of company value. Increased corporate value significantly influences the company's ability to fulfill its responsibilities to stakeholders, such as paying dividends to shareholders, borrowing interest expense to creditors, hiring employees and paying taxes to the government. Conclusion: This study also concludes that there are differences of firm size, dividend payout, tax burden, interest expense on cement company go public in Indonesia, while the salary load is not significant difference.

Frequency Analysis of Extreme Events Using the Univariate Beta Family Probability Distributions

This manuscript presents three families of distributions, namely the Beta, Beta Prime and Beta Exponential families of distributions. From all the distributions of these families, 14 statistical distributions of three, four and five parameters are presented that have applicability in the analysis of extreme phenomena in hydrology. These families of distributions were analyzed regarding the improvement of the existing legislation for the determination of extreme events, specifically the elaboration of a norm regarding frequency analysis in hydrology. To estimate the parameters of the analyzed distributions, the method of ordinary moments and the method of linear moments were used; the latter conforms to the current trend for estimating the parameters of statistical distributions. The main purpose of the manuscript was to identify other distributions from these three families with applicability in flood frequency analysis compared to the distributions already used in the literature from these families, such as the Log–logistic distribution, the Dagum distribution and the Kumaraswamy distribution. The manuscript does not exclude the applicability of other distributions from other families in the frequency analysis of extreme values, especially since these families were also analyzed within the research carried out in the Faculty of Hydrotechnics and presented in other materials. All the necessary elements for their use are presented, including the probability density functions, the complementary cumulative distribution functions, the quantile functions and the exact and approximate relations for estimating parameters. A flood frequency analysis case study was carried out for the Prigor RiverRiver, to numerically present the proposed distributions. The performance of this distributions were evaluated using the relative mean error, the relative absolute error and the L-skewness–L-kurtosis diagram. The best fit distributions are the Kumaraswamy, the Generalized Beta Exponential and the Generalized Beta distributions, which presented a stability related to both the length of the data and the presence of outliers.