Clustering, as an unsupervised learning method and an important process in data mining, is an aspect of large and distributed data analysis. In many applications, such as peer-to-peer systems, huge volumes of data are distributed between multiple sources. Analysis of these volumes of data and identifying appropriate clusters is challenging due to transmission, processing and storage costs. In this paper, a gossip-based distributed clustering algorithm for P2P networks called Efficient GBDC-P2P is proposed, based on an improved gossip communicative approach by combining the peer sampeling and CYCLON protocol and the idea of partitioning-based data clustering. This algorithm is appropriate for data clustering in unstructured P2P networks, and it is adapted to the dynamic conditions of these networks. In the Efficient GBDC-P2P algorithm, distributed peers perform clustering operation in a distributed way only through local communications with their neighbors. Our approach does not rely on the central server to carry out data clustering task and without the need to synchronize operations. Evaluation results verify the efficiency of our proposed algorithm for data clustering in unstructured P2P networks. Furthermore, comparative analyses with other well-established distributed clustering approaches demonstrate the superior accuracy of the proposed method.
Side weirs are installed on the main channels wall in sewage disposal systems and irrigation networks to divert the flow. In this paper, the flow pattern in rectangular channels along a side weir is predicted using the Volume of Fluid (VOF) scheme and the standard k–ε and RNG k–ε turbulence models. A comparison between the numerical and experimental results shows the high accuracy of the numerical model. For example, the values of root mean square error (RMSE), mean absolute relative error (MARE) and correlation coefficient (R) for the lateral velocity on z = 0.183 m level are calculated 3.782, 0.399 and 0.993, respectively. According to the simulation results, as the flow approaches to the side weir plane the flow field pressure decreases suddenly and at the end of the side weir the pressure increases. Also, by advancing the flow towards the downstream of the side weir the turbulent kinetic energy of the flow within the rectangular channel decreases. For all levels, the turbulent length scale value suddenly increases by reaching the flow to the end of the side weir. 相似文献
In this paper, a spectral Tau method based on Legendre Wavelet basis is proposed. For this purpose we present a stable operational Tau method based on Legendre Wavelet basis. This method provides an efficient approximate solution for weakly singular Volterra integral equations by using reduced set of matrix operations. An error estimation of the Tau method is also introduced. Finally we demonstrate the validity and applicability of the method by numerical examples. 相似文献
In this paper, Crude Monte Carlo method and importance sampling are utilized to determine the reliability of long-term changes in groundwater level. Furthermore, different data analysis methods are used to determine the abnormal patterns and to investigate the cause of spatial variations of failure probability. For this purpose, three methods including robust covariance, one-class SVM, and Isolation Forest are applied to define the decision function. In the preliminary detection of the outliers, DFFITS and COOK measures are used to confirm the existence of abnormal plains in a two-dimensional space. The validity of prediction results is verified through the developed method of uncertain monitoring by selecting the most significant outlier points. In addition, the abnormal pattern detection methods are compared using non-random pattern discovery decision functions. The reliability analysis of groundwater is conducted during the two periods from 1994 to 2007 and 2008 to 2021. In the second period, parts of the eastern part of the northwest, central parts of the desert of Iran, and areas from west-southwest and east-south-east to other regions exposed to a lower probability of passing through the critical conditions. In contrast, the outcomes confirm the occurrence of drought with probability more than 80% for most of the plains. Eventually, the importance sampling method showed the closest relation in the correct distribution of the decision function. In contrast, due to the cluster shape and density of the outliers, the upper part of the decision function was determined with high certainty in the discovery of abnormal plains. 相似文献
3D hierarchical heterostructure NiFe LDH@NiCoP/NF electrodes are prepared successfully on nickel foam with special interface engineering and synergistic effects. This research finds that the as‐prepared NiFe LDH@NiCoP/NF electrodes have a more sophisticated inner structure and intensive interface than a simple physical mixture. The NiFe LDH@NiCoP/NF electrodes require an overpotential as low as 120 and 220 mV to deliver 10 mA cm?2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, respectively. Tafel and electrochemical impedance spectroscopy further reveal a favorable kinetic during electrolysis. Specifically, the NiFe LDH@NiCoP/NF electrodes are simultaneously used as cathode and anode for overall water splitting, which requires a cell voltage of 1.57 V at 10 mA cm?2. Furthermore, the synergistic effect of the heterostructure improves the structural stability and promotes the generation of active phases during HER and OER, resulting in excellent stability over 100 h of continuous operation. Moreover, the strategy and interface engineering of the introduced heterostructure can also be used to prepare other bifunctional and cost‐efficient electrocatalysts for various applications. 相似文献
Patients with spinal cord injuries cannot move their limbs using their intact muscles. A suitable controller can be used to move their arms by employing the functional electrical stimulation method. In this article, a fuzzy exponential sliding-mode controller is designed to move a musculoskeletal human arm model to track an optimal trajectory in the sagittal plane. This optimal arm trajectory is obtained by developing a policy for the central nervous system. In order to specify the optimal trajectory between two points, two dynamic and static optimal criteria are applied simultaneously. The first dynamic objective function is defined to minimize the joint torques, and the second static optimization is offered to minimize the muscle forces at each moment. In addition, fuzzy logic is used to tune the sliding-surface parameter to enable an appropriate tracking performance. Simulation results are evaluated and compared with experimental data for upward and downward movements of the human arm. 相似文献
A mild and efficient method for the synthesis of thiochro meno[4,3-b]pyran and thiopyrano[4,3-b]pyran derivatives using MgO nanopowders as a catalyst is described. The MgO nanopowders were prepared via a green biosynthesis method using an extract of Rosmarinus officinalis leaves and were characterized by Field Emission Scanning Electron Microscopy and X-ray diffraction analyses. 相似文献
In this study, B12N12 nanocage sensor function for H2S absorption was examined theoretically. For this purpose, the interaction between B12N12 nanocage with H2S gas in both ground and excited states have been investigated by DFT and TD-DFT methods. Interaction between nanocage with H2S gas in ground state were studied with electron localization function, charge decomposition analysis and natural bond orbitals. TD-DFT calculations for B12N12 cage and Sc-substituted cage suggest that the optical properties of the cage can be improved by Sc-substitution. Survey the absorption uv spectrum of Sc@(BN)12 after gas absorption showed this substituted nanocage is more favorable as an optic sensor. UV–Vis spectra display new absorption peaks confirming sensing ability of Sc-substituted B12N12 for detection of H2S molecule. Subsequently in viewpoint of absorption, charge transfer mechanism via the photo-induced electron transfer process was investigated. Also desired nanosensor has short recovery time because adsorption energy of H2S molecule is not too large. So it is expected that Sc-substituted B12N12 nanocage acts as new potential nanosensor to detect toxic H2S molecule. 相似文献
The vibration analysis of rotating, functionally graded Timoshenko nano-beams under an in-plane nonlinear thermal loading is studied for the first time. The formulation is based on Eringen's nonlocal elasticity theory. Hamilton's principle is used for the derivation of the equations. The governing equations are solved by the differential quadrature method. The nano-beam is under axial load due to the rotation and thermal effects, and the boundary conditions are considered as cantilever and propped cantilever. The thermal distribution is considered to be nonlinear and material properties are temperature-dependent and are changing continuously through the thickness according to the power-law form. 相似文献
For the first time, the effect of calcination process on characteristics and catalytic performances of Pd supported on different MOFs (MIL-101(Cr), NH2-MIL-101(Cr), and HKUST-1) was evaluated. Besides, the various orders of calcination process and reduction one on Pd/MOF and Pd/calcinated-MOF were studied, and their performances in CO oxidation reaction were presented to find the effect of H2 and O2. Results showed that the effect of calcination and reduction processes on the catalytic activities and characteristics strongly depends on the nature of MOF. Among MIL-based catalysts, the catalyst with no calcination treatment showed the best activity. Among MNH2-based catalysts, high activity was obtained for Pd/MNH2, Pd/MNH2-C, and Pd/MNH2(RC) samples and Pd/calcinated-MNH2was the best. Catalytic activities of HKUST-1-based catalysts decreased with calcination due to high changes in their structures. The results are useful for predicting the performance of MOFs in oxidation processes, especially reactions in which high oxygen concentrations are involved. 相似文献