The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Zong-chang Yang - One of the best experts on this subject based on the ideXlab platform.
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Daily urban water supply modeling and forecasting based on the elliptic orbit model with weekly quasi-Periodic Extension
Urban Water Journal, 2018Co-Authors: Zong-chang YangAbstract:ABSTRACTModeling and forecasting for various time horizons of urban water supply are important for different operations within a utility company. This study proposes the ‘elliptic orbit model’ for daily urban water supply prediction from the viewpoint of time-series analysis. As additional efforts and costs are required to acquire and predict more different forecast variables, it is argued that many studies failed to carefully check whether such efforts and costs were deserved and to what degree they might ameliorate the prediction accuracy. Thus predictive modeling based on available water supply data has its own advantages. Only the water-supply time-sequence data is used and mapped into the polar coordinates to design the proposed ‘elliptic orbit model’, so the purpose of this study is to present one vivid approach for forecasting daily urban water supply in an intuitive and concise way. The proposed model archives satisfying experimental results and may inspire other applications.
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Daily user-online load forecasting for social network site based on the DFT resampling interpolation with Periodic Extension
International Journal of Information and Communication Technology, 2017Co-Authors: Zong-chang YangAbstract:Along with rapid development of the internet, a new type of information networks called 'online social networks' are emerging in popularity, which have been one global phenomenon. Then analysis and forecasting of user-online load movement for one social network site is increasingly important because of its significant effect on web traffic, information propagation, resource allocation, maintenance management and commercial operation. In this study, it is found that the daily online load movement roughly exhibits daily cyclical variations. Then with Periodic Extension for the daily user-online load movement, a forecast approach based on the called discrete Fourier transform (DFT) resampling interpolation is proposed, in which two-factor up-sampling is performed on the Periodically adjusted user-online load observed sequence to predict (estimate) its future movement. Experiments and result analysis indicate potentiality of the proposed method that it yields satisfying results in forecasting daily user-online load movements at the Chinese social network websites.
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Electric Load Movement Forecasting Based on the DFT Interpolation with Periodic Extension
Journal of Circuits Systems and Computers, 2015Co-Authors: Zong-chang YangAbstract:Electric load forecasting is increasingly important for the industry. This study addresses the load forecasting based on the discrete Fourier transform (DFT) interpolation. As the most common analysis method in the frequency domain, the conventional Fourier analysis cannot be directly applied to prediction. From the perspective of time-series analysis, electric load movement influenced by various factors is also a time-series, which is usually subject to cyclical variations. Then with Periodic Extension for the load movement, a forecasting approach based on the DFT interpolation is proposed for predicting its movement. The proposed DFT interpolation prediction model is applied to experiments of forecasting the daily EUNITE load movement and annual load movement of State Grid Corporation in China. The experimental results and analysis show potentiality of the proposed method. Performance comparisons indicate that the proposed DFT interpolation model performs better than the three commonly used interpolation algorithms as well as the classical autoregressive (AR) model, the ARMA model, and the BP-artificial neural network (ANN) model on the same forecasting tasks.
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Daily ambient air mean NO2 concentration modeling and forecasting based on the elliptic-orbit model with weekly quasi-Periodic Extension: a case study
Stochastic Environmental Research and Risk Assessment, 2014Co-Authors: Zong-chang YangAbstract:Air pollution has been an internationally growing concern. Modeling and forecasting daily movement of ambient air mean NO2 concentration is an increasingly important task for its adverse effects on human health. With weekly quasi-Periodic Extension for daily movement of mean NO2 concentration, the elliptic orbit model is introduced to depict its movement. Daily movement of mean NO2 concentration as a time-series is mapped into the polar coordinates to build the elliptic orbit model, in which each 7-day-movement is described as one elliptic orbit. Experiments and result analysis indicate workability and effectiveness of the proposed method. It is shown that with weekly quasi-Periodic Extension, daily movements of mean NO2 concentration at the given monitoring stations in China are well described by the elliptic orbit model, which presents a vivid description for analyzing daily movement of mean NO2 concentration in a concise and intuitive way.
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Modeling and forecasting daily movement of ambient air mean PM2.5 concentration based on the elliptic orbit model with weekly quasi-Periodic Extension: a case study
Environmental science and pollution research international, 2014Co-Authors: Zong-chang YangAbstract:Nowadays, the issue of air pollution has continuously been a global public health concern. Modeling and forecasting daily movement of ambient air mean PM2.5 concentration is an increasingly important task as it is intimately associated with human health that the air pollution has unignorable negative effects in reducing air quality, damaging environment, even causing serious harm to health. It is demonstrated that daily movement of mean PM2.5 concentration approximately exhibits weekly cyclical variations as daily particle pollution in the air is largely influenced by human daily activities. Then, based on weekly quasi-Periodic Extension for daily movement of mean PM2.5 concentration, the called elliptic orbit model is proposed to describe its movement. By mapping daily movement of mean PM2.5 concentration as one time series into the polar coordinates, each 7-day movement is depicted as one elliptic orbit. Experimental result and analysis indicate workability and effectiveness of the proposed method. Here we show that with the weekly quasi-Periodic Extension, daily movements of mean PM2.5 concentration at the given monitoring stations in Xiangtan of China are well described by the elliptic orbit model, which provides a vivid description for modeling and prediction daily movement of mean PM2.5 concentration in a concise and intuitive way.
Ichiro Yoshida - One of the best experts on this subject based on the ideXlab platform.
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Low-pass filter without the end effect for estimating transmission characteristics—Simultaneous attaining of the end effect problem and guarantee of the transmission characteristics
Precision Engineering, 2017Co-Authors: Yuki Kondo, Munetoshi Numada, Hiroyasu Koshimizu, Kasuhide Kamiya, Ichiro YoshidaAbstract:Abstract A Gaussian filter (GF) is the most commonly used low-pass filter of measuring surface roughness. However, undesirable distortions, called “end effects," occur near the end points of the data ends in GF. The transmission characteristics are one of the most important indicators that show the quality of a filter. Previously, it was only possible to obtain theoretical values for the transmission characteristics of filters whose weights were given by an explicit function. In recent years, it has also become possible to obtain the transmission characteristics of a filter whose weights are given by an implicit function. However, this method has a problem in that the values near the end points of the measurement data become significantly different from each other. The consequence is that end effects may occur in the filter outputs due to side effects of the Periodic Extension. In the case of a spline filter (SF) applied to open profiles, the transmission characteristics of a Periodic SF with an end effect can be obtained uniquely. However, the transmission characteristics of a nonPeriodic SF, which has no end effect, cannot be uniquely obtained. This results in a trade-off between the two states: end effects exist in a filter whose transmission characteristics can be obtained, and the transmission characteristics of a filter without end effects cannot be uniquely obtained. To address this problem, we propose a method for the GF processing that uses shearing, point symmetric Extension, and Periodic Extension, and produces no end effect but allows the transmission characteristics to be obtained. Previously, there was a problem with the proposed method in that the rationale was unclear regarding how to determine the reference points for point symmetric Extension. We resolved this and optimized the reference points. As a result, the proposed method was shown to be successful in not only resolving the end effects in the GF, but also obtaining the transmission characteristics.
Davide Rizzo - One of the best experts on this subject based on the ideXlab platform.
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handling borders in systolic architectures for the 1 d discrete wavelet transform for perfect reconstruction
IEEE Transactions on Signal Processing, 2000Co-Authors: Marco Ferretti, Davide RizzoAbstract:We propose a modified systolic architecture that implements the 1-D discrete wavelet transform (DWT) on the basis of the recursive pyramid algorithm (RPA) while correctly managing the border problem and obtaining perfect reconstruction. All the architectures so far described in the literature do not explicitly address the handling of borders and usually assume a zero-padding Extension. The RPA makes heavy use of this assumption, which produces very efficient systolic architectures. It is, however, well known that the zero-padding Extension does not allow perfect recovery of the original signal, if we compute exactly N coefficients. More coefficients are required either in the forward or in the inverse transform, and their production within the RPA scheme lowers the efficiency of the systolic architecture to a minimum. We introduce a modified RPA working on an extended transform with a compressed schedule that restores good values of efficiency (EC-RPA). We also propose a second version of RPA based on a Periodic Extension of the signal and of the transform (PE-RPA) that achieves perfect reconstruction by computing exactly N DWT coefficients. A reduced version of the second algorithm (R-PE-RPA) is tailored to the efficient computations of a fixed number of levels in the transform. The VLSI complexity of the management of borders is analyzed through synthesis from a VHDL description of the three algorithms. Synthesis results show that the controller required for PE-RPA can be as large as a ten-tap array. R-PE-RPA instead requires half this area. In both cases, the controller complexity scales sublinearly with the length of the input.
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MVA - On the Synthesis of a Controller for Handling Borders in Systolic Architectures for 1-D Discrete Wavelet Transform.
Journal of Machine Vision and Applications, 1998Co-Authors: Marco Ferretti, Davide RizzoAbstract:In this paper we describe the control subsystem of a systolic architecture that implements the 1-D discrete wavelet transform (DWT) on the basis of the Recursive Pyramid Algorithm (RPA) and that correctly manages the border problem adopting a Periodic Extension strategy to obtain a perfect reconstruction of the signal. Usually, the proposed architectures for DWT (either 1-D or 2-D) assume a zero-padding Extension. Periodic Extension of the input signal allows to set up a new algorithm (PE-RPA) that correctly recovers the input signal without additional computations. A detailed analytical description of this algorithm shows that a certain amount of control is mandatory, to have the underlining systolic structure perform the 1-D DWT computations correctly in time. In this paper, we show the design of the controller required for such a scheduling. The methodology used for such a design is a VHDL RTL description, with the subsequent optimised synthesis. The preliminary results show that the overall complexity of the controller compares to that of the systolic architecture in the case of a 10 stage filter (L=10) with a 20 bit data representation extended to 36 bits for multiplication. The dependency of the controller on the input signal size N is logarithmic, since the local memory fbr handling borders is O(L IogN). The overhead hidden within the handling of borders is clearly non negligible, and must be taken into account.
Yuki Kondo - One of the best experts on this subject based on the ideXlab platform.
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Low-pass filter without the end effect for estimating transmission characteristics—Simultaneous attaining of the end effect problem and guarantee of the transmission characteristics
Precision Engineering, 2017Co-Authors: Yuki Kondo, Munetoshi Numada, Hiroyasu Koshimizu, Kasuhide Kamiya, Ichiro YoshidaAbstract:Abstract A Gaussian filter (GF) is the most commonly used low-pass filter of measuring surface roughness. However, undesirable distortions, called “end effects," occur near the end points of the data ends in GF. The transmission characteristics are one of the most important indicators that show the quality of a filter. Previously, it was only possible to obtain theoretical values for the transmission characteristics of filters whose weights were given by an explicit function. In recent years, it has also become possible to obtain the transmission characteristics of a filter whose weights are given by an implicit function. However, this method has a problem in that the values near the end points of the measurement data become significantly different from each other. The consequence is that end effects may occur in the filter outputs due to side effects of the Periodic Extension. In the case of a spline filter (SF) applied to open profiles, the transmission characteristics of a Periodic SF with an end effect can be obtained uniquely. However, the transmission characteristics of a nonPeriodic SF, which has no end effect, cannot be uniquely obtained. This results in a trade-off between the two states: end effects exist in a filter whose transmission characteristics can be obtained, and the transmission characteristics of a filter without end effects cannot be uniquely obtained. To address this problem, we propose a method for the GF processing that uses shearing, point symmetric Extension, and Periodic Extension, and produces no end effect but allows the transmission characteristics to be obtained. Previously, there was a problem with the proposed method in that the rationale was unclear regarding how to determine the reference points for point symmetric Extension. We resolved this and optimized the reference points. As a result, the proposed method was shown to be successful in not only resolving the end effects in the GF, but also obtaining the transmission characteristics.
Marco Ferretti - One of the best experts on this subject based on the ideXlab platform.
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handling borders in systolic architectures for the 1 d discrete wavelet transform for perfect reconstruction
IEEE Transactions on Signal Processing, 2000Co-Authors: Marco Ferretti, Davide RizzoAbstract:We propose a modified systolic architecture that implements the 1-D discrete wavelet transform (DWT) on the basis of the recursive pyramid algorithm (RPA) while correctly managing the border problem and obtaining perfect reconstruction. All the architectures so far described in the literature do not explicitly address the handling of borders and usually assume a zero-padding Extension. The RPA makes heavy use of this assumption, which produces very efficient systolic architectures. It is, however, well known that the zero-padding Extension does not allow perfect recovery of the original signal, if we compute exactly N coefficients. More coefficients are required either in the forward or in the inverse transform, and their production within the RPA scheme lowers the efficiency of the systolic architecture to a minimum. We introduce a modified RPA working on an extended transform with a compressed schedule that restores good values of efficiency (EC-RPA). We also propose a second version of RPA based on a Periodic Extension of the signal and of the transform (PE-RPA) that achieves perfect reconstruction by computing exactly N DWT coefficients. A reduced version of the second algorithm (R-PE-RPA) is tailored to the efficient computations of a fixed number of levels in the transform. The VLSI complexity of the management of borders is analyzed through synthesis from a VHDL description of the three algorithms. Synthesis results show that the controller required for PE-RPA can be as large as a ten-tap array. R-PE-RPA instead requires half this area. In both cases, the controller complexity scales sublinearly with the length of the input.
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MVA - On the Synthesis of a Controller for Handling Borders in Systolic Architectures for 1-D Discrete Wavelet Transform.
Journal of Machine Vision and Applications, 1998Co-Authors: Marco Ferretti, Davide RizzoAbstract:In this paper we describe the control subsystem of a systolic architecture that implements the 1-D discrete wavelet transform (DWT) on the basis of the Recursive Pyramid Algorithm (RPA) and that correctly manages the border problem adopting a Periodic Extension strategy to obtain a perfect reconstruction of the signal. Usually, the proposed architectures for DWT (either 1-D or 2-D) assume a zero-padding Extension. Periodic Extension of the input signal allows to set up a new algorithm (PE-RPA) that correctly recovers the input signal without additional computations. A detailed analytical description of this algorithm shows that a certain amount of control is mandatory, to have the underlining systolic structure perform the 1-D DWT computations correctly in time. In this paper, we show the design of the controller required for such a scheduling. The methodology used for such a design is a VHDL RTL description, with the subsequent optimised synthesis. The preliminary results show that the overall complexity of the controller compares to that of the systolic architecture in the case of a 10 stage filter (L=10) with a 20 bit data representation extended to 36 bits for multiplication. The dependency of the controller on the input signal size N is logarithmic, since the local memory fbr handling borders is O(L IogN). The overhead hidden within the handling of borders is clearly non negligible, and must be taken into account.