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A novel trust recommendation model for mobile social network based on user motivation

ELECTRONIC COMMERCE RESEARCH 2021年第3期21卷 809-830页

作者： Yang, Gelan Yang, Qin Jin, Huixia Hunan City Univ Dept Comp Yiyang 413000 Peoples R China Sichuan Agr Univ Sch Business Dujiangyan 611830 Peoples R China Hunan City Univ Dept Informat Sci & Engn Yiyang 413000 Peoples R China

Traditional collaborative filtering recommendation algorithm has the problems of sparse data and limited user preference information. To deal with data sparseness problem and the unreliability phenomenon on the traditional social network recommendation. This paper presents a novel algorithm based on trust relationship reconstruction and social network delivery. This paper introduces the method of eliminating falsehood and storing truth to avoid the unreliable phenomenon and improves the accuracy of falsehood according to the user similarity formula based on the scale of contact established by users. In this paper, the problem of attack caused by the misbehaving nodes is investigated when the recommended information is disseminated in the existing trust model. In addition, a recommendation-based trust model is proposed that includes a defensive plan. This scheme employs the clustering techniques on the basis of interaction count, information Compatibility and node intimacy, in a certain period of time dynamically filter dishonest recommendation related attacks. The model has been verified in different portable and detached topologies. The network knots undergo modifications regarding their neighbors as well as frequent routes. The experimental analysis indicates correctness and robustness of the reliance system in an active MANET setting. Compared with the most advanced recommender system, the proposed recommendation algorithm in accuracy and coverage measurements show a significant improvement.

关键词： Trust relationship Mobile social network filtering algorithm Recommendation attack Recommendation management

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Multifunctional Wavelength-Selective Switch for Nyquist Pulse Generation and Multiplexing

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IEEE PHOTONICS TECHNOLOGY LETTERS 2018年第18期30卷 1641-1644页

作者： Takahashi, K. Watanabe, K. Inoue, T. Konishi, T. Osaka Univ Grad Sch Engn Suita Osaka 5650871 Japan Hamamatsu Photon KK Cent Res Lab Hamamatsu Shizuoka 4348601 Japan

We demonstrate optical Nyquist pulse train generation using a wavelength-selective switch (WSS) without an optical multiplexing circuit. The representative approach generating optical Nyquist pulse trains is based on spectral filtering with a WSS and optical time-domain multiplexing (OTDM) with an optical circuit. The use of the optical circuit causes difficulties when extending optical Nyquist pulse train technology to the near-infrared band because this band has no well-established OTDM modules. To resolve this problem, we assign the role of multiplexing to the WSS, in addition to spectral filtering. Furthermore, the WSS-only approach is expected to reduce optical losses and increase pulse-train parameter flexibility. Using only the WSS, we successfully generate optical Nyquist pulse trains in the near-infrared band and realize flexible control of pulse number, width, and interval. In the case of a 10-pulse train, optical loss due to multiplexing is improved by 8.0 dB compared with the conventional method.

关键词： filtering algorithm Nyquist pulse trains spatial light modulator wavelength selective switch

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Adaptive edge detection of rebar thread head image based on improved Canny operator

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IET IMAGE PROCESSING 2024年第5期18卷 1145-1160页

作者： Liu, Li Liu, Zijin Hou, Aishan Qian, Xuefei Wang, Hui Shenyang Jianzhu Univ Sch Mech Engn Shenyang 110168 Peoples R China China Acad Bldg Res Beijing Peoples R China North China Inst Aerosp Engn Sch Elect & Control Engn Langfang Peoples R China CABR Construct Machinery Technol Co Ltd Langfang Peoples R China China Petr Pipeline Bur Engn Co Ltd Langfang Peoples R China CABR Informat Technol Co Ltd Langfang Peoples R China

The quality of the rebar thread head is crucial for the connection between the rebars, thereby affecting the public safety of the building. The edge extraction of the thread image is the most important step in obtaining the accurate size parameters, which helps to complete online inspection of quality. Here, an edge detection method based on improved Canny operator is proposed to solve the problems on sensitivity to noise, existence of false edges, and lack of self-adaptability. Firstly, an improved adaptive median filtering algorithm is used to denoise the image. Then replace Sobel with Scharr to enhance the gap between pixel values, add 45 degrees and 135 degrees directional templates to prevent edge information loss as well. Besides, introduce a scale factor to improve the interpolation method for non-maximum suppression and reduce false edges. Finally, use Ostu operator to achieve adaptive extraction of high and low thresholds to complete adaptive edge detection. The qualitative analysis and quantitative results show that the improved algorithm can not only have a good visual effect, have good robustness and feasibility, but also be faster than other algorithms, which provide a basic guarantee for real-time online quality detection of the thread head. The edge extraction of the thread image is the most important step in obtaining the accurate size parameters, which helps to complete online inspection of quality. Here, an edge detection method based on improved Canny operator is proposed to solve the problems on sensitivity to noise, existence of false edges, and lack of self-adaptability. The qualitative analysis and quantitative results show that the improved algorithm can not only have a good visual effect, have good robustness and feasibility, but also be faster than other algorithms, which provide a basic guarantee for real-time online quality detection of the thread ***

关键词： adaptive edge detection filtering algorithm image processing improved Canny operator

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Sweep synchronization as a global propagation mechanism

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COMPUTERS & OPERATIONS RESEARCH 2006年第10期33卷 2835-2851页

作者： Beldiceanu, N Carlsson, M Thiel, S SICS SE-16429 Kista Sweden MPI Informat D-66123 Saarbrucken Germany

This paper presents a new generic filtering algorithm which simultaneously considers n conjunctions of constraints as well as those constraints mentioning some variables Y-k of the pairs X, Y-k (1 <= k <= n) occurring in these conjunctions. The main benefit of this new technique comes from the fact that, for adjusting the bounds of a variable X according to n conjunctions, we do not perform n sweeps in an independent way but rather synchronize them. We then specialize this technique to the non-overlapping rectangles constraint where we consider the case where several rectangles of height one have the same X coordinate for their origin as well as the same length. For this specific constraint we come up with an incremental bipartite matching algorithm which is triggered while we sweep over the time axis. We illustrate the usefulness of this new pruning method on a timetabling problem, where each task cannot be interrupted and requires the simultaneous availability of n distinct persons. In addition each person has his own periods of unavailability and can only perform one task at a time. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： global constraint filtering algorithm sweep timetabling

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Accurate three-dimensional tracking method in bistatic forward scatter radar

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2013年第1期2013卷 1-9页

作者： Hu, Cheng Zeng, Tao Zhou, Chao Beijing Inst Technol Dept Elect Engn Beijing 100081 Peoples R China

Accurate three-dimensional (3D) tracking in bistatic forward scatter radar (BFSR) is a challenging problem because of absent range resolution and poor measurements. In this article, an accurate 3D tracking method of BFSR is proposed. Aiming to overcome the filter divergence caused by large initial state estimation error, firstly, an accurate initial state estimation approach is presented based on analytic derivation and Levenberg-Marquardt algorithm, which has the potential to improve the accuracy of initial state estimation. Furthermore, in order to reduce the computation cost of filtering process and speed up the filtering convergence rate, the accurate initial state estimation and extended Kalman filter algorithm in BFSR are combined to achieve a precise target 3D tracking. Finally, the proposed accurate tracking method is verified through comparative analysis of the simulation results.

关键词： Forward scatter radar 3D tracking Initial state estimation filtering algorithm

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Predictive deviation filter for deadbeat control

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IET ELECTRIC POWER APPLICATIONS 2020年第6期14卷 1041-1049页

作者： Wang, Zitan Chai, Jianyun Sun, Xudong Lu, Haifeng Tsinghua Univ Dept Elect Engn Beijing Peoples R China

Deadbeat control calculates excitation by a differential equation model that takes measurements of state variables as initial values and instructions as terminal values. Ideally, this excitation can force state variables to track instructions in the succeeding control interval. However, in a practical system, noises in measured signals can mislead the control system and degrade its performance with increased ripples and harmonics. Therefore, some filters are often used in measurements, but their inherent delay can lead to inaccurate initial values and cause severe overshoots in dynamic cases. In this study, a new type filtering algorithm called predictive deviation filter is proposed for deadbeat control, which filters only the predicted deviation obtained by removing the expected values from measured ones, and then the real values of state variables are recovered. With this method, the influence of the filter delay can be limited only on the deviation which is a small part of the signal, significantly improving the accuracy of the initial values. Furthermore, a comprehensive frequency-domain analysis of the predictive deviation filter is provided. Finally, the new filtering algorithm is applied to drive control of permanent magnet synchronous motor. The simulation and experimental results verify the effectiveness and performance of this approach.

关键词： machine control frequency-domain analysis permanent magnet motors differential equations filtering theory synchronous motor drives predictive deviation filter deadbeat control differential equation model state variables terminal values control system filtering algorithm predicted deviation filter delay drive control permanent magnet synchronous motor comprehensive frequency-domain analysis

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Robust state estimator of stochastic linear systems with unknown disturbances

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IEE PROCEEDINGS-CONTROL THEORY AND APPLICATIONS 2000年第2期147卷 224-228页

作者： Kim, JH Oh, JH Korea Adv Inst Sci & Technol Dept Mech Engn Taejon 305701 South Korea

The design of a filtering algorithm when an unknown disturbance exists is described. An alternative method to solve the disturbance estimation problem is proposed, which is to reformulate it to a tracking problem by using the relation of filter update. The reformulation of the problem makes it possible to use an effective sliding surface and fast estimate against arbitrary disturbance. A disturbance estimator using the discrete sliding mode is designed and improved by introducing a prediction parameter. In addition, a disturbance detection algorithm having a moderate calculation cost is designed using filter update and innovations. The normalised testing parameter makes it possible to use the standard chi-square table to determine the threshold level. The stability of the suggested algorithm is given and simulation results are included to demonstrate the effectiveness of the proposed technique.

关键词： prediction theory General system theory tracking problem robust state estimator disturbance estimator Simulation, modelling and identification unknown disturbances prediction parameter stochastic linear systems sliding surface Time-varying control systems filter update filtering algorithm standard chi-square table linear systems Kalman filters Signal processing theory variable structure systems Discrete control systems threshold level Multivariable control systems discrete sliding mode filtering theory uncertain systems innovations state estimation disturbance estimation stochastic systems disturbance detection algorithm discrete systems normalised testing parameter

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Data assimilation for flow forecasting in urban drainage systems by updating a hydrodynamic model of Damhusaen Catchment, Copenhagen

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URBAN WATER JOURNAL 2020年第10期17卷 847-859页

作者： Babel, Mukand Tansar, Husnain Mark, Ole Weesakul, Sutat Madsen, Henrik Asian Inst Technol Water Engn & Management Pathum Thani Thailand DHI AS Horsholm Denmark Hydro Informat Inst Krung Thep Maha Nakhon Thailand

Accurate model-based forecasts (discharge and water level) are considered significant for efficient planning and management of urban drainage systems. These model-based predictions can be improved by assimilating system measurements in physically based, distributed, 1D hydrodynamic urban drainage models. In the present research, a combined filtering and error forecast method was applied for the data assimilation to update the states of the urban drainage model. The developed data assimilation set-up in combination with the 1D hydrodynamic model was applied at the Damhusaen Catchment, Copenhagen. Discharge assimilation represented significant potential to update model forecast, and maximum volume error was reduced by 22% and 6% at two verification locations. The assimilation of water levels had a minor impact on the update of the system states. The updated forecast skill using error forecast models was enhanced up to 1-2 hours and 6-7 hours lead time at upstream assimilation and downstream verification locations, respectively.

关键词： filtering algorithm auto-regressive model data assimilation 1D hydrodynamic model updating

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Kalman filter based 3D-stochastic inverse boundary element method for flaw identification and structural reliability prediction

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INVERSE PROBLEMS IN ENGINEERING 2001年第3期9卷 199-215页

作者： Liu, Y Liang, LH Jia, GS Zhejiang Univ Technol Dept Mech Engn Hangzhou 310014 Peoples R China

A stochastic inverse boundary element method (SIBEM) is developed for determination of three-dimensional (3D) flaws, stochastic boundary traction (load) and structural reliability parameters. SIBEM includes the direct solution of stochastic boundary element (SBEM) and the inverse analysis. Minimizing the difference of the initial guess and the objective values by Kalman filtering algorithm, makes it possible to predict the stochastic boundary loads, as weft as to determinate the defects and the structural reliability. Two numerial examples, which show the effectiveness of this paper, including the determination of unknown defects and unknown parameter distribution of random boundary traction, are presented and discussed.

关键词： SIBEM structural reliability filtering algorithm

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Correction of surface air temperature measurements from a mobile platform

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AGRICULTURAL AND FOREST METEOROLOGY 1999年 98-9卷 227-238页

作者： Achberger, C Bärring, L Univ Lund Dept Phys Geog S-22100 Lund Sweden

The use of vehicle-borne mobile measurement systems to study processes generating micro-scale temperature variations in the landscape requires precise knowledge of factors influencing the measurements. We reported results from field measurements with a sonic anemometer to determine the how deformation around a vehicle-borne mobile measurement system. These measurements were also used to develop a correction procedure that removes the smoothing induced by the thermal inertia of thermocouples. The procedure is based on Fourier analysis and consists of two components: a low-pass filter that removes noise and aliasing effects above a cut-off frequency and a filter specially designed to remove the effect of the thermal inertia of thermocouple. The correction procedure is applied to two mobile measurement runs acquired during NOPEX CFE1 and compared to sound-virtual temperature recorded at a reference mast. The overall statistics (mean, standard deviation, etc.) are not changed by the correction procedure, but substantial changes occur in the high-frequency part of the observed spectrum that is dominated by turbulent fluctuations during daytime and, during nights, temperature transitions at forest edges and other land-use changes. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： thermocouple Fourier analysis spectrum filtering algorithm spatial scale agro-climatic mapping sensor inertia

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