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To study the problems related to two-stage degradation characteristics of locomotive wheels, a two-stage Wiener process-based method for predicting the remaining service life was proposed. The wheel rim degradation model was established by using a two-stage Wiener process model, and the individual differences in the wheel degradation process were characterized by the random drift coefficient. The expectation maximum (EM) algorithm and Bayesian theory were used to achieve offline parameter estimation and online updating of the degradation model parameters. The change point in the wheel degradation process was determined and found via the Schwarz information criterion (SIC). Finally, an example of wheel rim degradation data from a certain locomotive was used for validation. The results show that, compared with the single-stage degradation model, the two-stage degradation model considering the change point is more in line with the field reality, and the prediction accuracy at 80% of the life quantile of the wheel is improved by 9.42%. The prediction of the remaining service life can provide a certain theoretical basis for the optimization of the wheel turning cycle. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic 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.)

Zero memory nonlinearity (ZMNL) and spherically invariant random process (SIRP) are two mainly used methods in compound Gaussian clutter simulations. Aiming at the problem that the shape parameters in the K and Pareto distributed radar clutter simulation based on the traditional ZMNL and SIRP methods can only be integer or semi-integer, by adding branches and using the additivity of the second parameter of Gamma function, it is proposed to transform the probability density function (PDF) of the Gamma function into second-order nonlinear ordinary differential equation. Furthermore, it is solved to generate Gamma distributed random numbers under arbitrary parameters, and the shape parameters of compound Gaussian distribution clutter is extended to general real numbers. The simulation experiments show that the proposed method is not only suitable for clutter simulation with non-integer or non-semi-integer shape parameter values, but also further improves the fitting degree. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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.)

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. 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.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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.)

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office 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.)

Copyright of Journal of Beijing University of Civil Engineering & Architecture is the property of Journal of Beijing University of Civil Engineering & Architecture Editorial Office 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.)

Copyright of Mycosystema is the property of Mycosystema Editorial Board 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.)

Copyright of China Brewing is the property of China Brewing Editorial Office 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.)

According to the characteristics of irregular random charge and discharge of electric vehicles and the requirements of on-line detection, it is difficult to ensure the accuracy of off-line experimental data analysis methods due to battery consistency problems. In this paper, an on-line closed-loop correction SOH (state of health） estimation architecture based on the idea of unscented Kalman filter (UKF) is proposed, which is based on the off-line SOH external indicator function. The advantage of this method is that it can quickly estimate the high-precision SOH value in the random discharge process and the algorithm complexity is relatively reduced. It is easy to implement in practical engineering and the proposed method has better robustness. Through verification, it can be proved that the SOH estimation method proposed in this paper has better practicability and higher estimation accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications 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.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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.)

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology 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 network would continue to evolve with changes in nodes and connections over the time. Aiming at the problem that traditional network representation learning algorithms cannot handle dynamic networks correctly, a dynamic continuous-time network representation learning algorithm based on random walks (DCTNE) is proposed. By defining a flexible node timing neighbor concept, a biased random walk process is designed. According to the time information, it can effectively explore the neighbors of different time series of nodes and model the influence of different neighbors, and learn the network representation. The experiment proves the effectiveness of DCTNE dynamic network timing information. On the link prediction task, the AUC value of DCTNE is up to 50% gain compared with other algorithms. On the node classification task, DCTNE also has significantly improved the performance. The results show that modeling the time dependence in the network is helpful for subsequent network analysis tasks. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. 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.)

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office 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.)

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group 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.)

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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.)

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering 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.)

Copyright of Journal of Northeast Petroleum University is the property of Journal of Northeast Petroleum University Editorial Office 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.)

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology 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.)

Objectives: At present, low earth orbit (LEO) satellites with missions, such as LEO navigation enhancement, earth observation and scientific application, require higher accuracy and real time performance of orbit parameters. Because of the limitations of GPS broadcast ephemeris errors, the accuracy of traditional real-time orbit determination using space-borne GPS measurements is still a long way to catch up with real-time centimeter-level orbit demand. The use of real-time orbit and clock corrections for precise positioning applications will be extended into orbit if they are available via a satellite link to geostationary orbit (GEO) satellites. However, the data link to GEO constellation may not be available over the polar regions. Methods: The centimeter -level real time precise orbit determination (RTPOD) method using space -borne GPS measurements with international global navigation satellite system service real time service (IGS RTS) data receiving interruption in the polar regions is studied. Firstly, the characteristics of ephemeris comprehensive errors caused by real time corrections and its short time extrapolation are analyzed. Based on the analysis, a pseudo-ambiguity is modeled as a stochastic process with piecewise random walk and estimated in the mathematical model of RTPOD to reduce the ephemeris comprehensive error, and then the centimeter-level accuracy can be realized. Finally, using GPS broadcast ephemeris and IGS-RTS products (CLK93), the on broad RTPOD data processing for one week GPS measurements from the GRACE C satellite is simulated by the SATODS software. Results: The experimental results show that, considering the receiving interruption of real time corrections in polar regions, the position and velocity accuracies are 7.04 cm and 0.20 mm/s, respectively. Conclusions: The proposed method is feasible and effective. [ABSTRACT FROM AUTHOR]

Sediment discharge in the Jingjiang reach has sharply reduced since the Three Gorges Project operation, and the channel has been scoured by the clear water in order to recover the sediment transport capacity. However, the recovery rate of nonuniform suspended sediment was different with the different bed material compositions along the Middle Yangtze River. Therefore, the equation of settling distance of nonuniform sediment is derived, based on the theories of Markov stochastic process and sediment motion. Then, according to the definition of saturation recovery coefficient ( α) based on the diffusion theory of suspended sediment, the formula of grouped saturation recovery coefficient (αi) is modified using the equation of settling distance; However, it ignores the effect of bed material composition (BMC) on suspended sediment recovery. For the actual process of sediment transport in the Jingjiang reach, a formula of αi is then proposed with the effect of the BMC being considered. These results show that: ① The value range of αi in this study was 0. 12—0. 27 at Shashi and Jianli when the influence of the BMC was not taken into account, but it became to the range of 0. 000 3—0. 171 8 and 0. 003 5—0. 157 9 respectively when considering the BMC effect; ② Among αi of different sediment groups, the relationship of αif for fine sediment > αim for medium sediment > αic for coarse sediment existed when the BMC effect was not considered, but the relationship of αif < αim < αic existed when considering the influence of BMC; and the recovery rate of suspended sediment at Shashi was higher than that at Jianli except for the recession period; ③ The variations of αi at Shashi and Jianli were sensitive to different groups during different periods, in which αi during the flood period was higher than the value during other periods. Through comparation and analysis, the proposed formula in this study can predict the value of αi for the Middle Yangtze River well, and it also providing a basis for further research on the recovery mechanism of suspended sediment in the reach downstream of the Three Gorges Dam. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering 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.)

In order to solve the problem of aero-engines' reliability evaluation of multi-degraded systems under competitive failure, a reliability evaluation method of related competitive failure between multi-degraded failure and sudden failure is proposed. The non-linear Wiener process and Gamma process with random effects are used to describe the degenerate failure process of the system, the appropriate Copula function is chosen to model the failure correlation of the multivariate degenerate system, and parameter of multivariate degradation-related failure model is estimated by Markov chain Monte Carlo method. The Weibull distribution is introduced to describe the sudden failure time, the proportional hazard model is used to construct the sudden failure rate function about the performance degradation, and the two-step maximum likelihood estimation method is used to identify the model parameters. Combined with the performance degradation data of aero-engines, the reliability evaluation of the multivariate degradation system under competitive failure is realized, and the validity and accuracy of the model are verified through the analysis results. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications 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 wear process of the wheel flange and the rolling circle diameter was described by the Gamma random process， and the method of calculating the reliability of the wheel flange degradation and the rolling circle diameter degradation was studied by using the Copula function and the fourth-order moment method， and the dynamic indexes of the train at different stages were obtained by dynamics software simulation. The reliability of the wheel degradation process with a rotation cycle of 200，000 km and the sensitivity of the wheel diameter degradation process were studied. The correctness of the method was verified by Monte Carlo simulation (MCS).The results showed that the reliability of wheels reaching the expected life is high when the rotation cycle is 200，000 km， and the reliability calculated based on the Copula function correlation failure degradation model is higher than that calculated by the independent failure model. The sensitivity study of the wheel diameter degradation reliability model indicates that the scheme with less reduction of wheel diameter should be selected during the rotation repair. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She 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 problem of feedback controllers designed to achieve adaptive synchronization was investigated for neutral neural networks with mixed delays and Lévy noises. The noise disturbance in the neural network model was driven by the Lévy stochastic process consisting of the Gaussian process and the Poisson point process, and involving continuous disturbances as well as discontinuous synaptic noises. Based on the Lyapunov functional, the Itos formula and the inequality analysis technique, the criteria to ensure adaptive stabilization for the error system were built. Moreover, the update rate of the feedback controller was given to enhance the adaptive synchronization of the response system and the drive system. Results of a simulation example show the effectiveness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications 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 rainflow cycle counting is carried out on seventeen random processes of band-limited white noise with different band widths, and a probability density function (PDF) model of rainflow amplitude for random processes of band-limited white noise is proposed. This model is a linear combination of a Rayleigh distribution and a Weibull distribution, where the undetermined coefficients are all functions of the spectral parameters of the random process. Data fitting is carried out on the rainflow amplitude PDFs of the seventeen random processes based on the proposed model, and the relationship between the parameters in the model and the spectral parameters of the random processes are investigated, and the formula of the model is determined. According to the rainflow cycle counting results of the random processes, the prediction accuracy of the proposed model is compared with that of Dirlik's model, which shows that the proposed model gives better prediction results than Dirlik's model. [ABSTRACT FROM AUTHOR]

In view of the influence of the change of the land slope on the performance of the broad width precision no-tillage planter for rapeseed, the planter and the air-assisted centralized metering device were taken as the research objects, and the mechanical models between rapeseed and circumscribed arc type hole, rapeseed-air flow and central distributor were built under different land slope. The stochastic process model of the seed feeding rate and seeding rate of the air-assisted centralized metering device was established. The effects of land slope along the working direction and rotation speed of seed feeding device on seed feeding rate were analyzed by EDEM simulation and the corresponding mathematical model was established. EDEM-CFD coupling simulation was used to analyze the influence of the land slope along the working direction on the seeding performance of the central distributor. The simulation results showed that the seed feeding decreased gradually with increase of the land slope angle in the range of -5°-5°. The variation of seed feeding rate could be up to 50% compared with no tilt when the absolute value of land slope angle was in the range of 3°-5°. The uniformity variation coefficient of seed quality of each seed outlet increased with the increase of land slope angle, and the uniformity variation coefficient ranged from 4.95% to 14.91%. The land slope had a significant effect on the seed feeding rate and the uniformity variation coefficient of seed quality of each seed outlet. The intelligent test platform of planting machines was used to simulate the field working effect of planter under the different land slope. The experiment results indicated that with the increase of absolute value of land slope angle along with the working direction, the angle range of the planter swing front and back, the angle range of the planter swing front or back in one way and the uniformity variation coefficient of the seed quality of each seed outlet all increased gradually. With the increase of the absolute value of the land slope angle, the operations of continuous uphill or downhill had little effects on the variation coefficient of seed feeding rate stability. The uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of it’s ranged from 4.76% to 13.85%. With the increase of the angle range of front and back reciprocating swing, the seed feeding rate had obvious changes, the uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of seed quality of each seed outlet ranged from 4.76% to 10.27%. The effect of front or back single swing on seeding performance showed with the increase of the angle range of front or back swing in one way, the variation coefficient of seed feeding rate was slightly higher than that of with no tilt, the uniformity variation coefficient of seed quality of each seed outlet increased gradually, and the uniformity variation coefficient of seed quality of each seed outlet ranged from 6.76% to10.71%. The average error of seed feeding rate between the theoretical calculated by the simulation model and the bench test was 4.28%. The matching relationship between the seeding quality, the land slope angle along the working direction and the rotation speed of seed feeding device can ensure the planter has the same seeding quality when the planter working on the land with slope similar to that on the flat land, which can provide a reference for the structure optimization of the planter and the air-assisted centralized metering device to meet the seeding operation under different land slopes. [ABSTRACT FROM AUTHOR]

In order to explore the mechanism of how bore damage leads to the decrease in firing accuracy and the rise in the ratio of elliptical shot holes, eventually leading to the end of a barrel life, the thermo-mechanical coupling finite element analysis (FEA) models of barrels with bore damage at 4 life stages, including undamaged barrel, middle-early life barrel, mid-life barrel, and end-of-life barrel，are established based on barrel life tests. Uniform design method is used to design the simulation test of interior ballistics process influenced by random factors of ammunition. The response values of muzzle disturbances of differently damaged barrels were acquired in the simulation test. The simulated results are in well agreement with the experimental data. The response surface equation for muzzle disturbance for taking ammunition random factors as independent variable and the rules of how ammunition random factors influence the muzzle disturbances of differently damaged barrels are obtained by using the partial least-squares regression method based on cubic B-spline curve and the uniform design-response surface method. The simulated and analyzed results show that the contribution of each ammunition random factor to the muzzle disturbances of differently damaged barrels is unequal. In order to reduce the muzzle disturbances of barrels in its later lifetime, the mass eccentricity of bullet and the initial yield strength of jacket material should be decreased, and the cylindrical diameter and charge weight should be moderate. [ABSTRACT FROM AUTHOR]

The satellite Fengyun 3C(FY3C) launched in 2013 and carried a global navigation satellite system (GNSS) occultation sounder, which is the first BDS/GPS compatible radio occultation sounder in the world and records both GPS and BDS measurements. It provides an opportunity for investigating the precision realtime orbit determination based on space‐borne GPS/BDS measurements. In order to realize the real‐time orbit determination based on space‐borne GPS/BDS measurements with decimeter‐level accuracy, this paper carries out in‐depth research in the following aspects. Firstly, the real‐time orbit determination mathematical model based on the space‐borne GPS/BDS carrier phase observations is introduced. Then the properties of the errors in the signal’s propagation path that originates from GPS/BDS broadcast ephemeris are analyzed, and the signal‐in ‐propagation path error(SIPPE) statistics of different kinds of GPS/BDS satellites are also presented. Based on the analysis, a pseudo‐ambiguity is modeled as a stochastic process and estimated in the real‐time orbit determmination(RTOD) filter to absorb the SIPPE error, and then the decimeter‐ level accuracy can be realized. The space‐borne GPS/BDS data from China’ s FY3C satellite are em ‐ ployed for the simulative RTOD test using the SATODS software. Results have demonstrated that the position and velocity accuracy of 30 cm and 0.3 mm/s, respectively, are achieved when using GPS/BDS carrierphase data and broadcast ephemeris. Although the accuracy of BDS broadcast ephemeris is obviously worse than that of GPS, orbit results of the GPS/BDS fusion solution with reasonable stochastic models for pseudo‐ambiguities will be slightly superior to that using single GPS data. For example, when the FY3C satellite flew over Asia/Pacific region where more BDS satellites can be tracked, the orbit accuracy can be improved by 10% with the GPS/BDS fusion solution. [ABSTRACT FROM AUTHOR]

The topological structure of geostationary earth orbit (GEO) communication satellite constellation network is usually very complex and it is often difficult to define system state accurately. In this paper, we first analyze the topological relationships of a GEO constellation system containing three working satellites and one warm backup satellite, and then define and aggregate the system operating states by means of stochastic process. Based on Kolmogorov theorem, differential equations of aggregated state residence probabilities are built. In addition, with Laplace transform and its inverse transform, reliability indexes of the constellation network are deduced. Furthermore, probability sensitivity of the system's visiting various state sets containing safe state subset, deteriorating state subset, alert state subset and failed state subset is studied with failure rate change of the backup satellite, which can provide quantitative support for improving the constellation network reliability and adopting a backup strategy. In the case study part, we study a specific GEO constellation system of a commercial company and compare the effect of different varied failure rates of the backup satellite, which supports the theoretical conclusion in the previous part. [ABSTRACT FROM AUTHOR]

Multi-table join is one of the most important query operations in the field of big data analysis, however, its implementation is expensive, which affects the timeliness of the big data analysis results. Online aggregation provides feedback of statistical significance far before the query finishes, which is of great significance. The existing work on multi-table join online aggregation conducted uniform sampling on every joining table, which results in low join result yield and estimation inaccuracy on grouping join queries. To solve this problem, this paper proposed the multi-table join online aggregation technique based on Markov chain, which transformed the multi-table join process into the random walk on Markov chain, constructed stratified sample on the walk start strata after determining the join order, and designed the corresponding sampling mechanism and estimation algorithm. The experiment was conducted on the online Hadoop platform, and the results demonstrate that the response time of technique outperforms the existing algorithms, and it owns efficient scalability [ABSTRACT FROM AUTHOR]

Copyright of Basic Sciences Journal of Textile Universities / Fangzhi Gaoxiao Jichu Kexue Xuebao is the property of Basic Sciences Journal of Textile Universities 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 fatigue life of the parts were estimated by using the Goodman linear correction method and the linear cumulative damage rule, and the working load was statistically analyzed by the rain flow count method, considering the impact of the load change and the strength degradation on the reliability of mechanical parts. Then, the gradient reliability mathematical model was set up with maximum load in equal time to replace the variable load by using Gamma random process simulating strength degradation. Finally, the expression of reliability sensitivity was derived by stochastic perturbation theory and four rank moment method. The torque shaft of coal mining machine was taken as an example, the fatigue life of the shaft under actual load was estimated and the each parameter variables' variation rule of dynamic reliability sensitivity during the fatigue life was given. Furthermore, the influence of the parameter variables' variation on torque shaft reliability was analyzed, and the Monte Carlo simulation method was used to verify the results. All analysis results show that the dynamic reliability analysis process adopted conforms actual working conditions, and can provide a method for dynamic reliability analysis of mechanical parts in real situations. [ABSTRACT FROM AUTHOR]

This paper proposes a kind of method considering the corrosion pipelines phased degradation model and the remaining useful life (RUL) prediction method under imperfect maintenance. Firstly, the total number of imperfect maintenance in the whole life should be set to 3 times, then the degradation process is divided into 4 stages. Secondly, under the theoretical framework of nonlinear staged random diffusion process with the intervention of maintenance activities, the failure law should be modeled, on the basis of the first time, the probability distribution of remaining useful life (RUL) is derived, and the real-time remaining useful life (RUL) estimation of the corrosion pipelines is realized. Then, the parameters in the degradation model are estimated by maximum likelihood estimation (MLE) and Bayesian updating strategy based on the condition monitoring (CM) data and the maintenance data of the corroded pipelines. Finally, the effectiveness of the model is verified by case studies. The results show that the degradation model can well describe the staged degradation process of corrosion pipelines under the imperfect maintenance intervention, and it can provide the credible results of the reliability assessment, which makes the corroded pipelines have a higher level of safe operation, thus overcoming the adverse effects of the over maintenance or under-repair resulted by traditional method and reducing the maintenance cost. [ABSTRACT FROM AUTHOR]

Electromagnetic stimulation is an important neuromodulation technique that modulates the electrical activity of neurons and affects cortical excitability for the purpose of modulating the nervous system. The phenomenon of inverse stochastic resonance is a response mechanism of the biological nervous system to external signals and plays an important role in the signal processing of the nervous system. In this paper, a small-world neural network with electrical synaptic connections was constructed, and the inverse stochastic resonance of the small-world neural network under electromagnetic stimulation was investigated by analyzing the dynamics of the neural network. The results showed that: the Levy channel noise under electromagnetic stimulation could cause the occurrence of inverse stochastic resonance in small-world neural networks; the characteristic index and location parameter of the noise had significant effects on the intensity and duration of the inverse stochastic resonance in neural networks; the larger the probability of randomly adding edges and the number of nearest neighbor nodes in small-world networks, the more favorable the anti-stochastic resonance was; by adjusting the electromagnetic stimulation parameters, a dual regulation of the inverse stochastic resonance of the neural network can be achieved. The results of this study provide some theoretical support for exploring the regulation mechanism of electromagnetic nerve stimulation technology and the signal processing mechanism of nervous system.

Copyright of Tourism Tribune / Lvyou Xuekan is the property of Tourism Institute of Beijing Union University 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.)

In order to solve the dynamic reliability problem caused by random load and strength degradation， the load and strength are considered as stochastic processes simultaneously. The maximum equivalent load is obtained by using the theory of sequence statistics， the strength degradation process of mechanical parts is described by Gamma process， and the dynamic reliability model is established. Consequently using the stochastic perturbation theory and the four-order moment technique， the solution formula for the dynamic reliability sensitivity is derived， solving the sensitivity problem of the parameters from arbitrary distribution. For variation， a dynamic reliability model for screw bolts was established. The dynamic curves of the sensitivity of each parameter variable vs. time were calculated with the said model， and were also verified by Monte Carlo method. The results show that the established model indicates the rule of reliability change of mechanical parts vs. time accurately. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications 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.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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.)

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Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control 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.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control 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.)