A Novel Fractional Frequency Filtering Method Based on Double-Side Small EMI Inductors

This paper is concerned with the regularization of linear ill-posed problems by a combination of data smoothing and fractional filter methods. For the data smoothing, a wavelet shrinkage denoising is applied to the noisy data with known error level δ. For the reconstruction, an approximation to the solution of the operator equation is computed from the data estimate by fractional filter methods. These fractional methods are based on the classical Tikhonov and Landweber method, but avoid, at least partially, the well-known drawback of oversmoothing. Convergence rates as well as numerical examples are presented.

Acoustic Droplet Vaporization in Acoustically Responsive Scaffolds: Effects of Frequency of Excitation, Volume Fraction and Threshold Determination Method

Based on the internal model principle, repetitive controller (RC) is capable of reducing periodic torque ripple by generating a compensating action that consequently needs to be synchronized with the original ripple. However, the synchronization is difficult to achieve using the conventional RC when the sampling frequency is not integer multiple of the speed (known as fractional delay issue) or when the speed varies widely. To solve this problem, this paper presents a fractional delay variable frequency torque ripple reduction method for permanent magnet synchronous machine drives using the combination of angle-based RC and deadbeat current control. Four aspects of innovations are included in the proposed control to improve the synchronization. The experimental results show that the proposed control can effectively reduce torque ripple, even during speed and load transient.

The airborne transient electromagnetic method has become a powerful tool to explore deep resource and tectonic structures. However, aircraft vibrations and flight environments produce very strong and complex nonlinear noise and result in poor data quality compared to ground transient electromagnetic methods. Consequently, the reduction of airborne electromagnetic noises is of vital importance to data inversion and imaging. To suppress and remove the nonlinear noise, we propose using kernel minimum noise fraction (KMNF), which is a nonlinear generalized method of minimum noise fraction. First, an adaptive variable window-width filtering algorithm is used to evaluate the noises and perform the preliminary denoising. Then, we adopt the two filter methods, which are minimum noise fraction (MNF) and KMNF to suppress the noise. The results show that these two methods can both suppress noise and make the decay curves smooth, but kernel MNF is more effective for the nonlinear characteristics of noise and it does not weaken the anomaly. Finally, field data from the Qinling mine area is processed, using the MNF and KMNF methods. The results show that nonlinear noise is suppressed by both methods but the results of KMNF are better than those of the linear MNF method.

Target detection in sea clutter is of great significance in military radar research. Because the characteristics of sea clutter are complex and easily affected by wind direction, the method of suppressing sea clutter by using sea clutter characteristics to reproduce is not advantageous. To address this problem, this paper focuses on direct extraction of target echo. According to the difference of fractional characteristics between target echo and sea clutter, fractional Fourier transform is introduced to extract target echo. In this paper, a fractional domain change coefficient clustering method is established to identify the range units of target, and a fractional domain filtering method based on the minimax is proposed to extract the target spectrum of target dominated range units, so as to separate the target echo from sea clutter. Simulated and measured experiments prove that this method can accurately identify targets and extract target information under various sea state and different number of targets.

A simple membrane fractionation method for determining the distribution of radioactivity in chemical fractions of Bacillus cereus

H-type motion platform with linear motors is widely used in two-degrees-of-freedom motion systems, and one-direction dual motors need to be precisely controlled with strict synchronization for high precision performance. In this paper, a synchronous control method based on model decoupling is proposed. The dynamic model of an H-type air floating motion platform is established and one direction control using two motors with position dependency coupling is decoupled and converted into independent position and rotation controls, separately. For the low damping second-order oscillation system of the rotation control loop, a new fractional order biquad filtering method is proposed to generate an antiresonance peak to improve the phase and control gain of the open loop system, which can ensure system stability and quick attenuation for external disturbances. In the multiple-degree-of-freedom decoupled control loops, a systematic feedback controller design methodology is proposed to satisfy the given frequency domain design specifications; a feed-forward control strategy is also applied to compensate the disturbance torque caused by the platform motion. The simulation and experimental results demonstrate that the proposed synchronization control method is effective, and achieves better disturbance rejection performance than the existing optimal cancellation filtering method and biquad filtering method.

Hyperspectral images are widely employed for geological mapping because of their high spectral resolution. In this article, we develop the mixture-tuned matched filtering (MTMF)method, which can provide highly accurate mapping using the minimum ground-based data. This method is applied in the Malayer region of western Iran, which is composed of various lithological units. MTMF and minimum noise fraction (MNF) methods were applied to a Thematic Mapper 5 (TM5) image, and minimum number of training data based on field observation were used to produce a suitable false-colour image in which locations of lithological units were given. Finally, classification of six desired lithological units was done by the maximum likelihood classification (MLC) method. Results of lithological mapping show that although minimum ground-based data were used, the accuracy of classification is 82.3%. In addition, evaluation of the above-mentioned false-colour image reveals that the algorithm presented enhances the separability of units in the image by 7.3%, which can partially compensate for the low spectral resolution of the image used.

It is known that analytical manipulation of the time-domain representation of fractional order transfer function is, hitherto, a challenging task. In this study, a controller design methodology based on the direct synthesis design method is proposed using bi-fractional order transfer function as a reference model and certain time-domain criteria. First, an analysis examines the effects of bi-fractional order transfer function parameters, that is, commensurate fractional order, damping ratio and natural frequency, on the system time-domain criteria. This examination has allowed us to set up a relation between damping ratio and commensurate fractional order. Next, a polynomial function fitting is established in order to express the damping ratio in terms of this commensurate order. Bi-fractional-order reference model is regenerated using the above-mentioned relationship. Furthermore, a control design algorithm that utilizes the newly derived bi-fractional order reference model is developed by considering control signal limitations. The proposed fractional order control design method is then compared with globally optimized fractional order proportional-integral-derivative (PID) controllers under the same circumstances and performance index. Finally, the implementation of the proposed controller design algorithm is done on a real-time active suspension system. The results are very satisfactory and incoherent with the simulations.

In this paper, a fractional order digital differentiator is designed by using Inverse multiquadric radial basis function (RBF). First, the RBF interpolation approach is described. Then, the non-integer delay sample estimation is derived by using RBF approach. Next, the Grunwald-Letnikov derivative and non-integer delay sample delay are applied to obtain the transfer function of the proposed method i.e. fractional order digital differentiator. The design accuracy of the proposed method is better then the conventional methods like examples Time domain least squares method, Fractional sample delay method and Frequency response approximation method.

In the wideband transmission digital beamforming technology, due to the aperture crossing phenomenon, we cannot simply replace the delay with digital phase shifting. Commonly used fractional delay methods include the windowing method, VFD filter and other methods, but the fractional delay filter often has a serious hardware resource consumption, which is not conducive to the realization of multi-channel beamforming on a single chip. In this paper, a time-delay beamforming method based on DDS parameter control is proposed, and the system structure of emission beamforming is further optimized on the basis of which to save more resource consumption.

Smallcell is emerging as a cost-effective solution for satisfying the huge demands of mobile data. It can be deployed at any place where mobile traffic is required without the need for cell planning. However, coexistence of many uncontrolled smallcells using the same licensed frequency band can result in serious interference problems. In order to utilize smallcell efficiently, it is highly desirable that the smallcell can self-organize the network and mitigate interference automatically. In this paper, we propose a dynamic fractional frequency reuse (FFR) method for reducing the intercell interference automatically and improving the spectral efficiency. Key features of the proposed method are sub-band optimization with a central manner and sub-band size adjustment with a distributed manner. The proposed method has a low complexity and can be implemented as a feature of a self-organizing network (SON) in smallcell. Simulation results verify the effectiveness of the proposed method.

Device-to-Device (D2D) communication enables direct communication among devices which are in close proximity to each other without traversing the data traffic to the evolved NodeB (eNB), thus it is affirmed to be one of the dynamic techniques in improving the network throughput and reducing traffic load of eNB. Fractional frequency reuse (FFR)-based cellular resource reuse scheme is a promising scheme which can relatively improve the system capacity and system overall spectral efficiency. However, integration of D2D communication into conventional cellular network introduces interference. This paper formulates the outage probability of D2D communication caused by the interference from the cellular users while reusing single cellular resource by two-pairs of D2D communications at a time. For fair distribution of cellular resources to both D2D pairs, we used Jain's fairness index method. Simulation results show the validity of the proposed method.

The concept of a vision correcting display involves digitally modifying the content of a display using measurements of the optical aberrations of the viewer’s eye so that the display can be seen in sharp focus by the user without requiring the use of eyeglasses or contact lenses. Our first approach inversely blurs the image content on a single layer. After identifying fundamental limitations of this approach, we propose the multilayer concept. We then develop a fractional frequency separation method to enhance the image contrast and build a multilayer prototype comprising transparent LCDs. Finally, we combine our viewer-adaptive inverse blurring with off-the-shelf lenslets or parallax barriers and demonstrate that the resulting vision-correcting computational display system facilitates significantly higher contrast and resolution as compared to previous solutions. We also demonstrate the capability to correct higher order aberrations.

This paper presents a quadrature VCO that can be reconfigured between 6 and 9 GHz frequency bands. The dual-band VCO comprises a 6 GHz LC VCO, two 1/2-dividers, two mixers, and two 3 GHz notch filters. The 9 GHz output is generated based on a fractional frequency multiplication method by mixing the 6 GHz VCO output with its divide-by-two signal. The VCO, implemented in a 0.18 /spl mu/m SiGe BiCMOS technology, shows a fast switching time of 3.6 nsec. The measured VCO phase noises are -106 dBc/Hz and -104 dBc/Hz at 1 MHz offset for 6 and 9 GHz modes, respectively, while draining 10.8 mA from a 1.8 V supply.