Kind Of Filter Research Articles

Effect of Ultraviolet Radiation on the Long-Term Stability of Dye-Sensitized Solar Cells

Ultraviolet (UV) radiation has been a significant issue in photovoltaics. It has much stronger energy than visible or infrared ray. In photovoltaics, large energy of UV is useful for the photogeneration, but it is also involved in long-term degradation. In this work, we focused on the effect of UV irradiation on the long-term stability of dye-sensitized solar cells (DSCs). TiO2, which is a good photocatalyst, has the absorption in UV region and TiO2 excited by UV is possible to deteriorate DSC performance. Five kinds of filters with various filtering ranges were applied for DSCs and their photovoltaic properties were measured in the long-term. UV irradiation initially contributed to the increase in the photogeneration. However, the UV irradiated DSC exhibited earlier start of degradation and more rapid deterioration than other filtered DSCs. Consequently, the unfiltered DSC exhibited 29.7% decrease in comparison with initial performance after 160 h UV irradiation while other filtered DSCs exhibited 13.5% decrease averagely.

Underwater square-root cubature attitude estimator by use of quaternion-vector switching and geomagnetic field tensor

This paper presents a kind of attitude estimation algorithm based on quaternion-vector switching and square-root cubature Kalman filter for autonomous underwater vehicle (AUV). The filter formulation is based on geomagnetic field tensor measurement dependent on the attitude and a gyro-based model for attitude propagation. In this algorithm, switching between the quaternion and the three-component vector is done by a couple of the mathematical transformations. Quaternion is chosen as the state variable of attitude in the kinematics equation to time update, while the mean value and covariance of the quaternion are computed by the three-component vector to avoid the normalization constraint of quaternion. The square-root forms enjoy a continuous and improved numerical stability because all the resulting covariance matrices are guaranteed to stay positively semidefinite. The entire square-root cubature attitude estimation algorithm with quaternion-vector switching for the nonlinear equality constraint of quaternion is given. The numerical simulation of simultaneous swing motions in the three directions is performed to compare with the three kinds of filters and the results indicate that the proposed filter provides lower attitude estimation errors than the other two kinds of filters and a good convergence rate.

Infectious complications of peritoneal dialysis

Peritoneal dialysis is one of three basic methods of renal replacement therapy. Others include hemodialysis and kidney transplantation. In peritoneal dialysis, the peritoneal cavity is used to clean the blood of excess unnecessary substances and water. The peritoneum is a thin membrane permeable to water and many substances, lining the organs inside the abdominal cavity. Briefly, the peritoneum can be considered a kind of filter. When performing peritoneal dialysis, a dialysis fluid is administered to the abdominal cavity, which discharges after some time, and this activity is repeated at planned intervals. The chemical composition of the fluid is appropriately selected for each patient so as to obtain optimally favorable results of dialysis. Water diffusion depends on the concentration in the fluid of glucose and other osmotic factors. Among the infectious complications of peritoneal dialysis, including drainage site infections, tunnel inflammation and peritonitis associated with peritoneal dialysis, the latter remains the most common and serious.

Filtration of dust in an electrostatically enhanced granular bed filter for high temperature gas cleanup

High temperature gas cleanup is an important technology. In order to develop an efficient filter for hot gas cleanup, three kinds of filters were built: 1) Rare earth tungsten (RE-W) cathode electrostatic precipitator (ESP), 2) classical granular bed filter (CGBF), and 3) electrostatically enhanced granular bed filter (EGBF). The effect of gas temperature, voltage, granule size, and bed height on the dust collection efficiency of the filters were investigated. It is found that the efficiency of the EGBF is the highest among the three filters. The efficiency of the double-zone RE-W cathode ESP ranks second, though decreasing collection area reduces the efficiency significantly. The efficiency of the CGBF is not high compared to the above two filters. On the whole, the EGBF is a very promising technology for hot gas cleanup, especially when cooperated with the RE-W thermionic emission cathode which is very suitable for particle charging at high temperature.

Digimums' online grocery shopping: the end of children's influence?

PurposeThis paper investigates children's influence on their mothers' online grocery shopping. As virtual shopping does not provide instant gratification, the authors explore how children between the ages of 7 and 11 are involved in the online purchasing process (before, during and after the purchase) with their digital mothers (digimums).Design/methodology/approachWe collected qualitative data from 27 separate semi-structured interviews of mothers and their children.FindingsChildren's influence during the online buying process exists and can be active, passive and/or proactive. The findings extend knowledge about children's influence by adding the notion of proactive influence where children use an intended approach to anticipate their mother's needs for grocery shopping and take initiatives. Children use less impulsive requests and become smart shoppers using more rational arguments to explain their requests. The online buying process contributes to children's online socialisation: They learn the importance of the shopping list, prices, discounts, brands and so on. Online socialisation at home might take the physical form of using digital devices (i.e. scanning) and entering the credit card code, which contributes to the children's learning.Originality/valueOnline buying virtualises children's relationship to objects, and the screen acts as a kind of filter. This makes their influence strategy less emotional and corporeal and more rational (smart shopper).

Flowing behavior with several kinds of filters using water experiment and MPS (Moving Particle Simulation) method

Flowing behavior with several kinds of filters using water experiment and MPS (Moving Particle Simulation) method

Constructing Some Logical Algebras with Hoops

In any logical algebraic structures, by using of different kinds of filters, one can construct various kinds of other logical algebraic structures. With this inspirations, in this paper by considering a hoop algebra or a hoop, that is introduced by Bosbach, the notion of co-filter on hoops is introduced and related properties are investigated. Then by using of co-filter, a congruence relation on hoops is defined, and the associated quotient structure is studied. Thus Brouwerian semilattices, Heyting algebras, Wajsberg hoops, Hilbert algebras and BL-algebras are obtained.

Efficient Image Restoration Methods for Image Recovery

Image Restoration is the one of the significant techniques to process an image. The process of taking a noisy image and obtaining the clean, original image is called as image restoration. This process is applied in every field where images have to be understood and analyzed. Image restoration is a method of recovering an original image from a degraded image. To restore corrupted image into its original form restoration techniques are used. The restoration techniques mainly focused to improve the image quality. Usually image processing techniques are implemented in the two domains, they are frequency domain or spatial domain. This paper mainly focused on different approaches to restoration, variations between frequency domain methods and spatial domain methods. Especially the relation between spatial and frequency resolutions and various filters in spatial and frequency domain. The present work shows the performance of different kinds of filters and these filters are analyzed by implementing and simulating on MATLAB.

Sisal fiber as an alternative to the construction of flexible fiber filters applied to water treatment

Abstract The recently developed flexible fiber filters (3Fs) are modular filtration units, which can satisfactorily remove solids at high filtration rates. Normally built with polyamide fibers, it is supposed that natural fibers can be used alternatively. This paper evaluated the performance of 3Fs using as filtering media sisal fibers in lieu of the polyamide ones. The sisal fibers were evaluated by means of scanning electronic microscopy and through solubility assays in hydrochloric acid and sodium hydroxide. Six filters with 28 mm of internal diameter were built, varying their length (25, 60, and 100 cm) and porosity (85 and 93%). The filtration system was fed with synthetic water, in-line coagulation was applied by the addition of 22.5 mg/L of aluminum sulfate, and filtration rates from 20 to 80 m/h were evaluated. Only the filter with 100 cm of length and 85% of porosity could work within the limit established (1 NTU), operating at 20 and 40 m/h. For all the studied configurations, the pressure drop was considerably low (less than 0.5 mH2O) when compared with 3Fs built with polyamide, which shows the potential of using this kind of filter as pre-filtration units or for less restrictive uses. This study showed that 3Fs can be adapted to include different configurations and materials, reducing their cost and making them appropriate for low-income countries.

Research on the Filters for Dual-Inverter Fed Open-End Winding Transformer Topology in Photovoltaic Grid-Tied Applications

Owing to the necessity of the transformer for the multi-parallel inverters connected to the medium-voltage (MV) grid, the conventional multi-parallel inverter topology can be reconfigured to the dual-inverter fed open-end winding transformer (DI-OEWT) topology to obtain lower output voltage harmonics, which can reduce the requirement of the filter inductance. However, due to the special structure of the DI-OEWT topology, the arrangement scheme of the filter can be more than one kind, and different schemes may affect the filter performance. In this paper, research on the existing two kinds of filters, as well as a proposed one, for the DI-OEWT topology used in photovoltaic grid-tied applications is presented. The equivalent circuits of these filters are derived, and based on this, the harmonic suppression capability of these filters is analyzed and compared. Furthermore, a brief parameter design method of these filters is also introduced, and based on the design examples, the inductance and capacitance requirements of these filters are compared. In addition, these filters are also evaluated in terms of the applicability for fault tolerance. At last, the analysis is verified through an experiment on a 30 kW dual-three-level inverter prototype.

Characterization and Mitigation of Single-Event Transients in Xilinx 45-nm SRAM-Based FPGA

This paper presents a new approach for analyzing the effect of single-event transient (SET) in SRAM-based field-programmable gate array (FPGA) devices, which are widely used in the space environment. New SET characterizing and mitigation techniques, including continuous monitoring and controlling of the test, are proposed to ensure proper operation of the device under test. This is vital for verifying the proper functioning of the design and performing online reconfiguration if required, since the effect of a single-event upset (SEU) on the device configuration bits may disrupt the SET detection and mitigation design. While many studies focus on SEU, latch-up, and cumulative radiation [total ionizing dose (TID)] effects on SRAM-based FPGAs, only a few published works refer to the SET effect. Moreover, in contrast to previous SET studies, this paper presents a quantitative assessment for SET probability under the real radiation environment and provides cross-sectional analysis for both SET and SEU effects at low linear energy transfers (LETs) (up to 0.925 MeV $\cdot$ cm2/mg). The SET experiments have been carried out at UCL Cyclotron (Belgium) accelerator using heavy ions and under alpha source irradiation. Experimental results indicate that SET examinations on SRAM-based FPGAs should be performed only at low LETs due to the high SEU rate compared to the SET rate. Several kinds of filters have been implemented and proposed for SET mitigation demonstrating a significant reduction of the SET transient effects. The proposed methodology may provide a basic model for future research studies on SET radiation effects on SRAM-based FPGAs, and assisting in selecting an immune FPGA-based platform for satellites applications.

Experimental research on an L-band multi-wavelength erbium-doped fiber laser based on a cascaded Sagnac loop and M–Z filters

In this paper, we proposed and experimentally demonstrated an L-band multi-wavelength erbium-doped fiber (EDF) laser with a cascaded Sagnac loop, M–Z interferometer filters and a non-linear optical loop mirror (NOLM). The NOLM acted as the intensity-dependent transmissivity; it can effectively alleviate the mode competition and beating caused by homogeneous broadening. The transfer characteristic of the Sagnac loop was investigated firstly and got the optimized parameters. Then the laser output spectrum with different kinds of filters in the cavity was experimentally tested when the pump power was fixed at 450 mW. The experimental results showed that the EDF laser with the cascaded filters in the cavity had a better performance, such as a better flat lasing bandwidth within 3 dB, higher side-mode-suppression ratio and more comb lines generated. The peak power fluctuation was less than 0.35 dB within a 30 min monitor time.

Research on the Linear Acceleration Sensor Signal Acquisition Technology Based on the High-Order Anti-Aliasing Cauer Filter

A linear acceleration sensor integrated into an inertial measurement unit and its signal processing technology are presented in this paper. Based on the characteristics of the acceleration sensor, before analog-to-digital conversion, a design method for optimizing and conditioning the output signal in levels of frequency with the high-order anti-aliasing Cauer filter is proposed. Compared with the previously published papers, here we not only focus on the anti-aliasing filtering effect under a single channel, but also pay more attention to the anti-aliasing filtering effect with more data to the same type of channels with the same cut-off frequency and different types of channels with different cut-off frequencies. Similar to other kinds of filters, this paper points out that the high-order anti-aliasing Cauer filter also has its inherent delay characteristic. And this paper also reveals the qualitative relationship between frequency and time delay in different testing environments by using various delay test data. Compared with the previously published papers, through the simple solution processing with the true attitude data, this paper further estimates the error of simple attitude signal processing.

Analytical synthesis of elliptic voltage‐mode even/odd‐ n th‐order filter structures using DDCCs, FDCCIIs, and grounded capacitors and resistors

Despite the recent publication of the analytical synthesis of voltage-mode even/odd- n th-order differential difference current conveyor (DDCC) and fully differential current conveyor II (FDCCII)-grounded resistor and capacitor universal Butterworth/Chebyshev filter structures, an elliptic voltage-mode even/odd- n th-order DDCC and FDCCII-based filter structure is yet to be presented in the literature. Under the restriction of a finite order, the elliptic filter is better at meeting the stringent cut-off rate of a very narrow transition band as compared to other kinds of filters, thus making the synthesis of such an elliptic filter to be extremely useful. In this study, one even- n th-order and two odd- n th-order elliptic filter structures are analytically synthesised using DDCCs and FDCCIIs. The feasibility of such structures is validated through H-spice simulations on the proposed elliptic third-order low-pass and elliptic fourth-order low-pass, high-pass, band-pass, and band-reject filters.

Convolutional Neural Network-Based Fractional-Pixel Motion Compensation

Fractional-pixel motion compensation (MC) improves the efficiency of inter prediction and has been utilized extensively in video coding standards. The traditional methods of fractional-pixel MC usually follow the approach of interpolation, i.e., they adopt different kinds of filters, either fixed or adaptive, to interpolate fractional-pixel values from integer-pixel values in a reference picture. Different from the interpolation approach, in this paper, we formulate the fractional-pixel MC as an inter-picture regression problem, which is to predict the pixel values of the current to-be-coded picture from the integer-pixel values of a reference picture, given a fractional-pixel motion vector that relates the two pictures. We then propose to adopt convolutional neural network (CNN) models to approach the regression problem, inspired by the recent advances of CNN. Accordingly, we propose fractional-pixel reference generation CNN (FRCNN) for both uni-directional and bi-directional MC in video coding. We further investigate how to train FRCNN by using encoded video sequences, and empirically study the effect of different training data and different CNN structures. Moreover, we propose to integrate FRCNN into the high efficiency video coding (HEVC) scheme, and perform a comprehensive set of experiments to evaluate the effectiveness of FRCNN. The experimental results show that our proposed FRCNN achieves on average 3.9%, 2.7%, and 1.3% bits saving compared with HEVC, under low-delay P, low-delay B, and random-access configurations, respectively.

A novel method for estimating the distribution of convective heat flux in ducts: Gaussian filtered singular value decomposition

ABSTRACTA new regularization approach for the unconstrained linear least square problem is proposed and assessed. This approach improves the classical methods based on the singular value decomposition approach by employing the Gaussian filter, a kind of filter which has been proved to be effective in several applications related to noise suppression. In particular, as a benchmark, it is hereby considered the estimation of the heat flux density at the internal wall surface in a forced convection problem in ducts, by solving the inverse heat conduction problem in the solid wall only using temperature distribution available at the exterior boundary. Results on both synthetic and experimental data are reported with the aim of discussing the effectiveness of the proposed method in comparison to other similar solution approaches.

A Novel Approach to ECG R-Peak Detection

Electrocardiogram (ECG) signal processing and analysis is becoming more and more popular as it is useful in diagnosis and prognosis of human heart and clinically automatic machine estimation is based upon it. R-peak is the most important component in ECG beat and is widely used to investigate normal and abnormal subjects (patients). From the last few decades, R-peak detection in ECG has been the most challenging topic in the biomedical research. As QRS complex has high frequency in ECG as compared to other waves (P, T, U-wave), so majority of algorithms estimate QRS complex by either filtering or suppressing the lower frequency waves, including various artifacts like baseline wander, power line interference, and electromyograph noises. This paper demonstrates a new kind of ECG denoising algorithm based on self-convolution window (SCW) concept. The SCW based on Hamming window, herein referred to as Hamming self-convolution window, is used to design a new kind of filter which possesses negligible ripples in the stop band, as compared to the conventional window-based filters. This algorithm is validated on MIT-BIH arrhythmia database and the results outperform in terms of sensitivity, positive predictivity, and error rate obtained as 99.93%, 99.95%, and 0.117%, respectively, as compared to the other well-established works. The approach has also outperformed the results of well-established window-based filters (Hamming and Kaiser) in terms of reduced false negative, false positive, and error rate.

State maps on semihoops

Abstract In this paper, we introduce the notion of state maps from a semihoop H 1 to another semihoop H 2, which is a generalization of internal states (or state operators) on a semihoop H. Also we give a type of special state maps from a semihoop H 1 to H 1, which is called internal state maps (or IS-maps). Then we give some examples and basic properties of (internal) state maps on semihoops. Moreover, we discuss the relations between state maps and internal states on other algebras. Then we introduce several kinds of filters by state maps on semihoops, called SM-filters, state filters and dual state filters, respectively, and discuss the relations among them. Furthermore we introduce and study the notion of prime SM-filters on semihoops. Finally, using SM-filter, we characterize two kinds of state semihoops.

Complex structures of the virtual in the formation of an associative-figurative plan of a musical work

Complex structures of the virtual in the formation of an associative-figurative plan of a musical work

New insights about interference suppression algorithm based on analog circuits and linear filtering method in ELF communication

In order to improve the communication quality in the extremely-low-frequency communication effectively, a kind of new insight based on analog circuits and linear filtering method for interference suppression is proposed, the latter mainly achieves by the joint diagonalization of the correlation matrices. The proposed algorithm takes place the filter coefficients by a linear combination of eigenvectors, the problem of interference suppression is converted into the solution of constructed coordinates. Besides, three kinds of filters are designed based on the mean square error criterion, the derivation process is given in detail, and several performance evaluation indices are also provided. And the derivation results show that the proposed algorithm can become common filters in speech enhancement when the number of chosen eigenvectors is a certain value. Finally, some experiments are performed in a laboratory environment. And the experimental results show that the proposed algorithm can suppress the interference effectively, and the compromise between the number of interference suppression and the degree of signal distortion can be controlled by changing the number of chosen eigenvectors, the proposed algorithm has potential performance gain.