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The potential for natural disasters in Indonesia is very high, because it is located on the Pacific Ring of Fire (an area with a lot of tectonic activity) and the confluence of three large tectonic plates, namely the Indo-Australian plate, the Eurasian plate and the Pacific plate. Predicting potential cases of natural disasters in Indonesia needs to be done, this is an effort to prepare a natural disaster management budget by the government. Therefore, this study aims to predict potential cases of natural disasters in Indonesia. The data used are cases of natural disasters that occurred in Indonesia. The method used is the Poisson Process to analyze the probability of natural disasters that will occur. From the results of the research, the probability of occurrence is obtained by the number of cases of natural disasters that will occur. Based on the research results, it can be used as a basis for the government in preparing disaster management budgets. [ABSTRACT FROM AUTHOR]

We studied a scour in a drainage canal of the Cheboksary hydrosystem tailrace on the Volga river. To protect the hydrosystem tailrace from scouring, we proposed flexible stream-guiding grids that are installed in the stream and effectively affect its kinematics in the bottom area. We calculated in MathCad a system of vortices that occur when the flow runs against adjacent plates of a grid. Due to the replacement of flexible elements of a grid with flat plates that divide the flow into separate jets, it became possible to use a method for calculating kinematic characteristics based on the model of A.Ya. Milovich. We calculated flow velocities in areas before the plates, in the space between the plates, and behind the grid. The results of calculations of grid parameters in MathCad were confirmed by an experimental study based on a model of a hydrosystem spillway dam. During the experimental study based on the 1:100 scale model in a hydraulic flume, we measured the kinematic characteristics of the flow using a multi-channel thermal anemometer. The measurements were carried out according to the Froude criterion. The values of thermal equivalents of flow velocities obtained using thermal anemometers were processed with Excel built-in statistical functions. The values of dispersion, confidence probability, and Student's criterion were obtained. As a result of the experiments performed with and without installing the grid model, a significant deformation of velocity diagrams before and behind the baffle was revealed. Due to the flow deviation from the bottom, the bottom velocities were significantly reduced in the lower part of the model, in an unprotected riverbed area. In the upper part of the model, in front of the grid, the change in the area of velocity diagrams was similar to the effect of a barrier on the flow. We established the high efficiency of the proposed device and the stability of the baffling effect in relation to changes in the flow rate. [ABSTRACT FROM AUTHOR]

Variance analysis is a key task of controlling. The quality of this analysis is a key precondition for the manager to make decisions. The task of the controller is to produce analytical reviews of the variances in timely manners. Demi models, which perform variance analysis, are being developed and applied for such reviews. It is important to understand that the Demi model is an analytical comparison of two sets of the same structure. The synergic effects of the partnership between managers and controllers mostly depend on the quality of diagnosis provided by these models. In this paper, we will present two of the most important and complex models of classical deviation analysis: analysis of sales variance and direct material variance analysis. Business result distributions are a plan and a realization. On the basis of such diagnostics, the determination of therapy, which is expressed in the form of a corrective action plan, follows. [ABSTRACT FROM AUTHOR]

An insurance insurer has a risk of loss. The risk of loss occurs if the insurer must bear claims beyond his ability. However, the insurer can reduce this risk by utilizing reinsurance. This paper intends to examine a reinsurance loss model developed by Panjer and Willmot in 1992, to process a group of data so as to produce information needed by actuaries in making decisions. Here is described the steps that must be implemented, and the calculation process is assisted by a computer application program to make it easier. This model is used to meet the need for information on the distribution of total claims, premium stop loss and variance for various retention levels. The calculation results show this model is the most effective for the number of policies and small benefits. Because the greater the number of policies and benefits, the more number of arrays and elements needed in each iteration and computer application program. So that it can quickly produce information needed by actuaries to support decision making. [ABSTRACT FROM AUTHOR]

Copyright of Zbornik Radova / Proceedings SKEI (1986-5945) is the property of University Vitez, Bosnia & Herzegovina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research conducted at farms in mountain areas have shown that the average age at first calving is 849.15 days (28 months and 5 days). The variability of this index is extremely large with the minimum of 570 days (19 months) and a maximum of 1350 days (45 months). It follows that the average age at first breeding would be 18 months and 10 days. At first glance this figure fits perfectly within the limits recommended by the literature, but the reality is different. Because of the desire to have the calving group against grazing, insemination the heifers are at the younger age of 18 months, few matings are made at 18 months. The two peaks in the graphical presentation of the variability of age at first calving and calculating statistical parameters show correctness of the statement. The first peak is given by the inseminated calved at less than 18 months of age and the second of the ones inseminated too late. The distance between the two peaks is 390 days, corresponding to the delay of the insemination of the calves with one year. The standard deviation (s) is of 159.48 days, and the coefficient of variation (V%) is 18.78. The standard deviation from the mean (± SX) is 12.45 days. The high value of the coefficient of variability as well as the standard deviation is due to the presence of the two peaks of the variation string that was previously discussed. Premature insemination of heifers at an early age and its delay is damaging for cattle breeder generating significant economic losses. [ABSTRACT FROM AUTHOR]

In the present paper, the probability distribution function is derived for the sum of squares of random variables for nonzero expectations. This distribution function enables one to develop an efficient one-step algorithm for phase ambiguity resolution when determining the spatial orientation from signals of satellite radio-navigation systems. Threshold values for rejecting false solutions and statistical properties of the algorithm are obtained. [ABSTRACT FROM AUTHOR]

Some industry export competitiveness indices are dependent on the first-order moments of the data but not the second-order moment. As the main form of second-order moment, variances can be used for evaluation of export competitiveness. According to the conditional variance of exports growth rate and the GARCH models, industry export competitiveness can be divided into three categories: strong, General and weak States. Using the GARCH models for export competitiveness research can meet the need of horizontal comparison and longitudinal analyses. The empirical study of the export competitiveness of wind energy industry among some nations have shown that, it is feasible and effective for using GARCH model method to study on export competitiveness. [ABSTRACT FROM AUTHOR]

In this paper, we define variance of the fuzzy random variables through alpha level. We have a theorem that can be used to know that the variance of fuzzy random variables is a fuzzy number. We have a multi-objective linear programming (MOLP) with fuzzy random of objective function coefficients. We will solve the problem by variance approach. The approach transform the MOLP with fuzzy random of objective function coefficients into MOLP with fuzzy of objective function coefficients. By weighted methods, we have linear programming with fuzzy coefficients and we solve by simplex method for fuzzy linear programming. [ABSTRACT FROM AUTHOR]

The article is aimed at the reliability and sensitivity analyses of the resistance of large circular cylindrical storage tanks storing crude oil. The reliability was quantified on behalf of the Cornell reliability index. It is shown how the Cornell reliability index is influenced by the tank shell thickness change. The sensitivity analysis of the reliability function was elaborated. The results of experimental research were applied to numerical evaluation. It was shown that the random variability of yield strength influenced the reliability in a dominant way. Reliability and sensitivity analyses were elaborated by applying the Latin Hypercube Sampling method. [ABSTRACT FROM AUTHOR]

Singh et al. [1]suggested Hartley-Ross type unbiased estimators of the finite population mean using auxiliary variables. We propose a new Hartley-Ross type unbiased estimators based on the estimators presented by Kadilar and Cingi [2, 3]. We obtain the variances of the unbiased proposed estimators and show that these estimators are more efficient than those given in Singh et al. [1] and Kadilar and Cingi [4, 5], in theory. The findings of this theoretical comparison are also supported by a numerical example. [ABSTRACT FROM AUTHOR]

Because of the speckle nature of the light reflected from rough surfaces the signal quality of a vibrometer suffers from varying signal power. Deep signal outages manifest themselves as noise bursts and spikes in the demodulated velocity signal. Here we show that the signal quality of a single point vibrometer can be substantially improved by diversity reception. This concept is widely used in RF communication and can be transferred into optical interferometry. When two statistically independent measurement channels are available which measure the same motion on the same spot, the probability for both channels to see a signal drop-out at the same time is very low. We built a prototype instrument that uses polarization diversity to constitute two independent reception channels that are separately demodulated into velocity signals. Send and receive beams go through different parts of the aperture so that the beams can be spatially separated. The two velocity channels are mixed into one more reliable signal by a PC program in real time with the help of the signal power information. An algorithm has been developed that ensures a mixing of two or more channels with minimum resulting variance. The combination algorithm delivers also an equivalent signal power for the combined signal. The combined signal lacks the vast majority of spikes that are present in the raw signals and it extracts the true vibration information present in both channels. A statistical analysis shows that the probability for deep signal outages is largely decreased. A 60 fold improvement can be shown. The reduction of spikes and noise bursts reduces the noise in the spectral analysis of vibrations too. Over certain frequency bands a reduction of the noise density by a factor above 10 can be shown. [ABSTRACT FROM AUTHOR]

The sunlight reflection process in the sea surface, considering a two-dimensional geometric model with variable reflection angle, is examined and the corresponding equations are derived. A synthetic data surface is used to calculate the corresponding glitter pattern. An analysis of the relationship between the variance of the surface slopes and the variance of the intensity values in the glitter pattern are calculated considering a gaussian distribution and a non-gaussian distribution of the surface slopes. The results obtained for both distributions are compared and presented graphically. [ABSTRACT FROM PUBLISHER]

Innovation processes result from a series of decisions and these are influenced by the perceived risks and success metrics faced by the decisionmaker. Aiming to understand whether innovation risks and success metrics change during and between innovations, four hypotheses were developed and a questionnaire-based survey was adopted targeting managers of mechanically based manufacturers. Respondents were asked to indicate the importance of perceived risks throughout specific innovations for four domains of risk: marketing, technical, organizational and financial. Respondents were also asked to identify changes in type and magnitude of innovation risk and success metric. Descriptive and statistical tests were conducted to analyse the data. The results suggest that innovation risk changes in type and magnitude during and between innovations and success metrics change in type and magnitude during innovation. This study calls for situation specific research to provide helpful advice to practitioners [ABSTRACT FROM AUTHOR]

A novel simplification of database technique is proposed to explicitly account for compromise of low cost and high detection performance used to fault identification in the practical industrial processes. Based on the principle of Mahalanobis distance, the samples with the similar characteristics are replaced by the mean of them, so that the number of raw data set is reduced easily. Moreover, the supper ball domains of mean and variance of samples are presented, which not only retain the statistical properties of raw data set but also avoid the reduction of data unlimitedly. Finally, numerical examples and simulations are given to illustrate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

In this paper, for the assignment problem with the elements of effective matrix are random variable, by using the restriction and complementary relation between mathematical expectation and variance in decision making and the synthesis effect description of random variable, an operable solution model for random assignment problem has been developed, combining with the characteristic of assignment problem, we give the concrete scheme based on genetic algorithm, finally, we analyze its performance through an example. All these indicate that, this solution model can effectively merge decision preference into the assignment process, posses interesting feature of strong interpretability, easy operation and higher computation efficiency. [ABSTRACT FROM PUBLISHER]

In this paper, we will use a novel measure of information called Cumulative Residual Entropy (CRE) to develop a new measurement of risk and compare it with variance, then conclude the existence of variance is sufficient condition for existence of CRE and there exists a positive linear correlation between CRE and standard-deviation in experiment study. We apply it to solve risk measure problem for some special heavy-tail distribution of non-existence variance. [ABSTRACT FROM PUBLISHER]

The problem of shadowing is particularly significant in high-resolution satellite imaging (HRSI) which causes either a reduction or total loss of information in the image. The research on segmenting shadow regions is of great significance for image interpretation and it is a supportive tool to detect manmade structures. This paper proposes a solution to the problem of automatic extraction of shadow features in color satellite images with high spatial resolution. The algorithm separates shadow from non-shadow by considering the spatial properties of the segmented regions. Experiments are executed on high resolution satellite images, and the results confirm the validity of the proposed method. [ABSTRACT FROM PUBLISHER]

Increasing the resolution of a video intra frame using various interpolation techniques not only gives a blurring effect but also results in the loss of fine details and critical edge information. In order to resolve this problem, an efficient, no reference, hybrid interpolation technique is proposed here. The proposed method makes use of a combination of anticipatory, spatial domain, region adaptive, unsharp masking operation coupled with Lanczos-3 interpolation for retaining some of the fine details and critical edge information in the reconstructed video frame. The region adaptive unsharp masking is a preprocessing approach which sharpens the intra frame regions locally as per their statistical local variance so as to compensate the blurring caused by the subsequent Lanczos-3 interpolation technique. The degree of sharpening is increased as per the rise in the statistical local variance of a neighborhood and vice versa. Furthermore, the unsharp masking operation is made globally adaptive by multiplying the unsharp mask with a global scaling factor which is obtained by adding one to the global variance of an intra frame. Experimental results reveal that the proposed method outperforms most of the existing interpolation techniques in terms of peak-signal-to-noise-ratio (PSNR) as well as visual quality for different types of video sequences. [ABSTRACT FROM PUBLISHER]

Image denoising is challenging due to the difficulty to differentiate noise from image fine details. Convolution with a Gaussian mask is a widely used method for denoising. In this paper we propose, based on the relation between linear diffusion and Gaussian scale space, estimators of both the variance and window size of the discrete Gaussian filter applied to image denoising. To achieve content adaptive estimators, we also propose a structure under noise measure based on the median absolute deviation from the image gradient. Our simulations show that the proposed automated filter performs comparable or exceeds non-linear diffusion, while being of significantly lower complexity. [ABSTRACT FROM PUBLISHER]

Based on the idea of the difference method, in this paper, the difference method is applied to the calculation of the variance and covariance. The variance and covariance formulas are transformed as some new formulas by the difference method. The articles presented some original new variance and covariance formulas whose form that contains the individual difference, and leads to some corresponding new expansion formulas. The calculation of the variance and covariance about this method is less implicated with the changes of the overall sample. Finally, the theoretical analysis and practical application of image denoising show the feasibility of the new formula. [ABSTRACT FROM PUBLISHER]

This paper presents an adaptive fuzzy filter combined with median filter (AFM) to the reduction of intensive salt and pepper noise in gray level images. Firstly, noisy pixels are detected using spatial neighborhood and variance of the pixel values. Then, noisy pixels are mainly removed with adaptive fuzzy filter, and then median filter is used for removing rest of the noisy pixels. The proposed method is able to reduce intensive salt and pepper noise in gray level digital images while preserving image details, and textures very well. [ABSTRACT FROM PUBLISHER]

In this paper, we presented a new method for job scheduling and modeled the access requests to web pages in computer network or internet with job scheduling in single machine. We simulated this model in two kinds of problems: 1. Small scaled problems (10 users). 2. Large scaled problems (100 users). The purpose of all problems is to find the minimum amount of mean and variance time. Since these problems are NP-hard, we proposed one type of innovative V shaped arrangement for job scheduling. It's possible to find the optimal response for small scaled problems with little spent time, so by examining all possible states the optimal responses (minimum mean and variance) were found and evaluated. [ABSTRACT FROM PUBLISHER]

The groundwater sampling and nitrate nitrogen testing were carried out for 13 times from 2005 to 2011 in order to investigate the nitrate nitrogen dynamic change of groundwater in the intensive agricultural area of Daxing district and explore its control countermeasures. The results indicated that the mean value of nitrate nitrogen in groundwater of this area was 1.58 mg/L, which met the criterion of the second level water quality in national criterion of groundwater quality, and in this study area the regional anisotropy caused by nitrate in groundwater was enlarged. The average concentration of nitrate nitrogen in groundwater from grain field was significantly higher than those from orchard and the other type of field, while it was slightly higher than that from vegetable field. Mean values of nitrate nitrogen in groundwater from vegetable field had a positive linear correlation with those of whole area in different sampling times. Effective countermeasures to reduce the risk of nitrate pollution in groundwater in Daxing district should be considered including rationally using agricultural inputs in planting area with intensive agricultural activities, carrying out effective water management measures, formulating corresponding laws and rules of groundwater nitrate pollution prevention and control, reinforcing the propaganda of popular science and improving the environmental consciousness of the public. [ABSTRACT FROM PUBLISHER]

Histograms are widely used for estimating the density of a continuous signal from existing data. In some practical applications, they are also employed for entropy estimation. However, a histogram involves implicitly a discretization procedure because the unknown density is approximated by a piecewise constant density model. In the previous literature, the impact of the discretization procedure on the accuracy of the entropy estimate was either ignored or evaluated in the particular case of a regular histogram, in which all bins are equally wide. In this work, we provide bounds on the performance of the histogram-based entropy estimators without relying on the restrictive assumptions which have been used by other authors. The proof of our theoretical results is mainly based on concentration inequalities which have been already employed to analyze the performance of histograms as density estimators. After establishing the theoretical results, we illustrate them by numerical examples. [ABSTRACT FROM PUBLISHER]

Moving variance is a signal used in many applications such as propeller speed identification, EMG artifact extraction, and lane-change recognition. It is also used in the preparation of numerous physiological signals for classification and measurement applications because it can be quickly calculated and reflects the movement or power contained in the signal. This paper investigates the effect of using a weighted moving variance. This paper proposes to quantify the effect of window type and window length on the properties of the moving variance signal. The features used in the time domain characterization are average value and event duration. The parameters were calculated for two signals, one from a respiration band and one from a pressure sensor array. The effect of window type and length was similar on the data from both sensor types. For these measurements, the triangular window was least sensitive to signal fluctuations, whereas the hanning window was the most sensitive. Preliminary figures suggest that an increase window length results in a shorter detected event. [ABSTRACT FROM PUBLISHER]

Learning based on kernel machines is widely known as a powerful tool for various fields of information science including signal processing such as function estimation from finite sampling points. One of central topics of kernel machines is model selection, especially selection of a kernel or its parameters. In our previous works, we investigated the generalization error of a model space itself corresponding to a selected kernel in kernel regressors. In this paper, we discuss the generalization error in a model space corresponding to a selected kernel in kernel regressors; and prove that the variance of a learning result is reduced when we adopt a kernel corresponding to a larger reproducing kernel Hilbert space. [ABSTRACT FROM PUBLISHER]

Variance, a common statistical measure reflecting degree of deviations between mean and individuals, could be used to describe the degree of gray level changes. Hence, it can be utilized to depict and extract image transition region. Unfortunately, variance is sensitive to salt & pepper noise. To solve this problem, a modified variance-based transition region extraction and thresholding method is presented in this paper. The proposed method performs statistic analysis on image local window to exclude salt & pepper noise, improving accuracy of transition region extraction. In addition, we also develop a scheme for ruling out this type of noise in image thresholding result, further enhancing its noise immunity for salt & pepper noise. The proposed algorithm was compared with famous local entropy-based method and gray level difference-based one on a variety of images, and experimental results show its effectiveness and noise immunity for salt & pepper noise. [ABSTRACT FROM PUBLISHER]

This paper analyzes effects of stochastic phase spectrum differences on phase-only correlation (POC) functions. We assume phase spectrum differences between two signals are statistically constant for frequency indices. That is, they have identical probability density function for all frequency indices. We derive the general expressions of the expectation and variance of the POC functions. Relationships between the POC functions and the phase spectrum differences are formulated. This result mathematically guarantees the validity of the POC functions used for similarity measure in matching techniques. [ABSTRACT FROM PUBLISHER]

The paper generally deals with the effects of a change in variance activities when computing the criticality node of a PERT network diagram. The main aim of the paper is to analyze the effects of a change in variance activities for two different approaches used when computing the criticality node. In order to achieve the aim, a hypothesis is formed that the change in variance activity should affect the computation of the criticality probability of nodes. The analysis is applied to a sample PERT network diagram comprising 9 nodes and 14 activities. A time analysis is developed using the PERT method, and the criticality node is computed using both approaches. The computed results serve as input for further statistical processing. [ABSTRACT FROM AUTHOR]

Ant Colony Optimization (ACO) is a popular research field these years. Ants choose paths where pheromone concentration is higher and modify the environment they visited. However, in the context of multi-service in multi-level and multi-domain optical network, the capacity of inter-domain links is limited. Congestion may be occurred at inter-domain links. In this paper, ant colony optimization algorithm based on load balancing is proposed. Ants follow paths not just depend on pheromone alone, we also take available resources on the link as a factor too. Simulations show the proposed method could reduce the traffic blocking probability, and realize load balancing within the network. [ABSTRACT FROM PUBLISHER]

In this paper a simple, novel and automatic method for classification of breast malignancy in digital mammogram images is proposed. It is based on the similarity/differences between the contour extracted from the mammogram image and its nearest circular approximation. The nearest circular approximation of extracted contour is obtained by considering the centroid of tumor as its centre and arithmetic mean of maximum and minimum radial distances of contour points from the centroid, as its radius. The similarity between the fitted circle and tumor contour is measured in terms of variance of radial distance of contour from the centroid, as a feature for classification. The simulation results show that for a set of 150 tumor contours, the proposed method gives 96.67% accuracy. The performance obtained in terms of the receiver operating characteristic (ROC) parameters like accuracy (Ac), sensitivity (Se), specificity (Sp), and positive (PPV) and negative predictive values (NPV) are 96.67%, 0.9873, 0.9437, 0.9512 and 0.9853 respectively. [ABSTRACT FROM PUBLISHER]

Performance of a power line communication system is severely deteriorated by fading and multipath effect. Transmitted signal propagate along a shortest path between the transmitter and the receiver, but additional path (echoes) should also be considered. This will result in a multipath scenario with frequency selective effect. The impulsive noise is considered time variant, has short duration, random occurrence with a high power spectral density (PSD). It causes bit error in the signal. Using orthogonal frequency division multiplexing (OFDM) technique, the effect of impulsive noise and fading can be improved greatly. In this paper, an analytical approach using diversity reception is carried out to examine the performance improvement of a power line channel in fading and impulsive noise. The system bit error rate (BER) is compared numerically for both binary phase shift keying (BPSK) and OFDM system. The BER results show that there is significant improvement in OFDM. Also the performance is remarkably upgraded using diversity reception. The BER performance is investigated using multiple antennas and also calculated analytically. [ABSTRACT FROM PUBLISHER]

The objective of the present paper is the sensitivity analysis of the steel plane frame load-carrying capacity. Methodology based on Sobol’s variance is used for the sensitivity analysis. Sensitivity analysis is used to analyze how sensitive a frame load-carrying capacity is with respect to change of initial imperfections. Input imperfections are of random origin. Majority of the input imperfections were measured and their random realizations computed using their histograms whilst employing the Monte Carlo method. The Monte Carlo method was applied to calculation of sensitivity indices. The model output is the load-carrying capacity calculated with used geometrical nonlinear finite element solution in each run of the Monte Carlo method. [ABSTRACT FROM AUTHOR]

This paper proposes a method for identifying persons by the use of the lifting wavelet parameters learned by kurtosis-minimization. Our learning method uses desirable properties of kurtosis and wavelet coefficients of a facial image. Exploiting these properties, the lifting parameters are trained so as to minimize the kurtosis of lifting wavelet coefficients computed for the facial image. Since this minimization problem is an ill-posed problem, it is solved by the aid of Tikhonov’s regularization method. Our learning algorithm is applied to each of the faces to be identified to generate its feature vector whose components consist of the learned parameters. The constructed feature vectors are memorized together with the corresponding faces in a feature vectors database. Person authentication is performed by comparing the feature vector of a query face with those stored in the database. In numerical experiments, the lifting parameters are trained for each of the neutral faces of 132 persons (74 males and 58 females) in the AR face database. Person authentication is executed by using the smile and anger faces of the same persons in the database. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

An impedance irregular network is proposed to investigate electrical fluctuations of biomolecules anchored between Ohmic contacts. We take rhodopsin as prototype of a biomelecule and as source of fluctuations we consider the random oscillations of the distances between aminoacids (link oscillation model) or alternatively those of the position of the aminoacids around their static value (node oscillation model). The network impedance and its variance are then investigated as function of the amplitude of the fluctuations. Analogies and differences between the results of the two models are discussed and some open problems are identified. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

For the BCI research to classify the different imagined movements of both left and right hands, a method using wavelet packet decomposition for feature extraction and using SVM for pattern classification was adopted. Firstly discusses the wavelet packet transform in depth and brings out an idea of taking wavelet packet coefficients' variance as feature into account, then extracts the feature serials after wavelet packet decomposition for channel C3 and C4, finally, classify the patterns by using linear SVM. The result shows that the maximum classification accuracy is 86.43% and the feature of variance is suitable. So, the method this paper used for feature extraction and pattern classification is more efficient and simpler, and it gives a new reference for BCI. [ABSTRACT FROM PUBLISHER]

An abstract of the article "User Reviews Variance, Critic Reviews Variance, and Product Sales: An Exploration of Customer Breadth and Depth Effects" by Xuefeng Liu, Feng Wang, and Eric Fang, is presented.

Research Question What happens in marketing stays digital. Online consumer reviews afford great opportunities for firms to facilitate the formation of a favorable online reputation. Like other content such as social networks, blogs, microblogs and media sharing sites in the User Generated Content (UGC) area that uses the Internet to facilitate conversations, online consumer reviews are flourishing on the Internet every day. Previous research has studied online consumer reviews' influence on consumers (Mayzlin 2006), product quality signals (Senecal and Nantel 2004), and informational roles (Sun 2012). Motivated by a better understanding of consumers and providing a useful tool for companies to monitor the online consumer review distributions, this study has the following main research questions: Research question 1: Based on some theoretical foundation, is there a modern transformation for coefficient of variations (CV) to be used by companies? Research question 2: In terms of information roles of online consumer reviews, is there any difference among two distribution measures, such as CV and variance? Method and Data This study uses a quantitative research design, including a mixture of theoretical model developments and empirical examinations. The empirical analysis makes use of consumer ratings of video games that were posted on a major online retailer website. Video games provide a good data content for this study. Based on a list of over 100 games all released during one fixed month period, game characteristics and detail review information were collected. Summary of Findings For the first research question, two modern transformations for CV are proposed. They are simple to use and can provide insights about online consumer reviews. After examining empirical review data and conducting statistical analysis, the second research question is answered. Over time, more consumers are providing reviews on these video game products. Furthermore, the percentage of onestar reviews has a significantly negative effect on CV of online consumer reviews, but not on variances. Key Contributions This research intends to fill in a research gap calling for useful distribution measurements of online consumer reviews. In today's dynamic marketing environment and fast-changing consumer trends, companies can be proactive and keep an eye on their consumers by adopting CV of online consumer reviews. [ABSTRACT FROM AUTHOR]

We investigate the theoretical and empirical implications of longitudinal data in strategy research. Theoretically, longitudinal data allow strategy researchers to distinguish between relationships among constructs within versus between firms. Empirically, longitudinal data contain information about two types of relationships: within-firm and between-firm relationships. We provide three empirical studies to examine between-firm and within-firm relationships in strategy research. Study 1 investigates the relative between-firm versus within-firm variance in a number of variables used in strategy research. Studies 2 and 3 use simulation techniques to assess the statistical power and bias of techniques (e.g., random effects, fixed effects, etc.) used by strategy scholars to analyze longitudinal data. Based on our review and empirical findings, we offer a number of recommendations to strategy scholars utilizing longitudinal data. [ABSTRACT FROM AUTHOR]

The investigation results of estimators properties for periodically correlated random processes characteristics obtained on the base of discrete time realization are given. Bias and variance formulae for the estimators ofmean and covariance Fourier coefficients are found. The conditions for discretization interval when aliasing effects do not occur are obtained. The dependences of estimator characteristics on discretization interval and realization length for modulated signals are analyzed. [ABSTRACT FROM PUBLISHER]