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This letter studies the design of hybrid precoding in millimeter-Wave (mmWave) multiple input multiple output-non orthogonal multiple access (MIMO-NOMA) systems. To guarantee the rate performance for all served users, we formulate the optimization problem of joint analog precoding (AP) and digital precoding (DP) vectors based on maximum and minimum (Max-Min) fairness to maximize the minimal achievable rate of users, i.e., we design different HP vectors for each user from the perspective of fairness. This can be solved by the proposed two-stage optimization scheme. First, the AP matrix and the DP vectors of each user are alternately designed, where the AP and DP vectors can be obtained by using the Semi-Definite Relaxation algorithm and the proposed boundary-compressed particle swarm optimization (BC-PSO) algorithm, respectively. Then, the optimal scaling factors obtained based on the Karush-Kuhn-Tucker (KKT) condition are introduced to further to improve the Max-Min rate. Simulation results show that the proposed scheme performs better than existing schemes. [ABSTRACT FROM AUTHOR]

Designing fitness-based adaptive scaling factor (F) is an effective method to enhance the performance of differential evolution (DE) algorithms. This paper investigates the correlations between F and fitness values of target vectors, base vectors and difference vectors. The correlations are described by the notations of monotonicity and nonlinearity. Monotonicity is used to examine whether the optimization performance of DE and the fitness values of certain vectors have positive or negative correlation. Nonlinearity denotes the operation in which nonlinear mappings are used to redistribute the values of F in [0, 1] so as to boost the optimization performance. These two aspects of correlations are empirically tested on the Numerical Optimization Competition benchmark functions in IEEE Congress on Evolutionary Computation. Simulation results reveal different qualitative and quantitative correlations between F and fitness values of different vectors. Then, a new F that combines these relations is designed. Its strength is numerically verified by testing different CEC Benchmark functions.

Space products have high reliability and will experience multi-stage development with respective tests after each stage. Due to the limit of budget and time-to-market, the tests usually have small sample sizes and short durations. A few or no failures are more likely to appear in such tests for high-reliability products. In practical engineering, reliability assessment will not be satisfactory if only depending on data from the current test. And this problem will be improved if multi-stage data is included. In this paper, a scaling factor method is adopted to deal with the conversion problem of the data in the previous stage. Then the Bayesian posteriori estimations of the reliability parameters are obtained by the Markov Chain Monte Carlo (MCMC) sampling method. After two-dimensional integral is calculated, the confidence lower limit of reliability can be given accurately. A case study is carried out to illustrate the effectiveness of the proposed method.

This article introduces an augmented adaptive unscented Kalman filter (KF). The proposed novel technique is suitable to simultaneously estimate both the diagonal process noise covariance matrix and the unknown inputs, thus combining previously reported KF estimators for unknown inputs (dual or joint KF) and for covariance matrices (adaptive KF). A selective scaling method is also introduced to improve the convergence property of the suggested KF. The development of the novel KF is also motivated by a specific estimation problem related to crane systems. Cranes represent a special class of weight handling equipment as they are underactuated and described by nonlinear dynamics such that the load present oscillatory behavior. In addition to the increasing need for their automation in various industrial fields, these features also make them a benchmark system in control engineering with numerous control laws reported in the literature for sway elimination and trajectory tracking. A common issue to realize most of the advanced control laws on real, eventually industrial size cranes is the necessity to know the sway angle and frictions on the configuration variables. It is shown in simulation and also with real experiments on a reduced size overhead crane system that the suggested KF is suitable to estimate both the sway angles and the frictions. [ABSTRACT FROM AUTHOR]

The regularization method has been utilized to address the ill-posed inverse problem of electrical resistance tomography (ERT). As one of the regularization methods, the total variation (TV) regularization method has the advantage of edge-preserving. A majority of research has been focused on the study of the penalty term in the TV method. In this article, a novel TV regularization based on iteratively reweighted least squares (TV-IRLS) method is proposed, in which, $L_{1}$ -norm is applied to the fidelity term, and a weighting matrix is applied to convert the $L_{1}$ -norm to $L_{2}$ -norm when calculating the objective function, which reduces the difficulty of solving the $L_{1}$ -norm. An improved generalized cross-validation method is adopted to determine the optimal regularization parameter (RP) automatically, and an automatic method is presented for the selection of the threshold value in the weighting matrix to guarantee the accuracy and speed of the solution. Meanwhile, a scaling factor is introduced to constrain the solution and ensure the stability of the solution. For verifying the performance of the proposed TV-IRLS regularization method, both numerical simulation and static experiments are carried out in the image reconstruction of ERT through qualitative and quantitative analysis. The results demonstrate that the proposed TV-IRLS regularization method performs well in improving the quality and resolution of the reconstructed images in ERT. Besides, it is more robust to data noises compared with the Tikhonov regularization method and TV regularization method. [ABSTRACT FROM AUTHOR]

Image retargeting aims to obtain high visual quality of target images for human vision. Through semantic segmentation and understanding of input images, we can better preserve the important semantic regions, so as to effectively improve the performance of image retargeting. Benefit from the successful application of deep neural network in the field of semantic segmentation, in this paper, we propose a novel image retargeting approach using semantic segmentation and pixel fusion. Compared with existing image retargeting methods, our approach can effectively reduce geometric distortion during image retargeting by finely reallocating scaling factors for each region based on the semantic segmentation results. Experimental results demonstrate that the proposed approach can well preserve important semantic regions while leaving less unnatural geometric distortion. Our approach also shows the important role of semantic segmentation and understanding of scenes in image retargeting in detail. [ABSTRACT FROM AUTHOR]

Based on the subthreshold current and equivalent transistor models, a new device-parameter-oriented average DC power model average DC power (PDC) for symmetric operation of junctionless double-gate mosfet (JLDGFET) working on the low-power CMOS subthreshold logic gate is developed. Although short-channel effects can increase P DC significantly, the balanced transistor strength will reduce PDC more efficiently by improving the consistency of transistor strength between P-JLDGFET and N-JLDGFET. Being similar to DIBL, the minimum channel length that corresponds to the allowable maximum PDC in designing the low-power logic gate can be determined according to the scaling theory. Although the inverter (INV) may act as the fundamental building unit for the logic circuits due to its least gate counts among INV, nand, and nor, it consumes the most PDC among these logic gates. The minimum DC power PDC,min can be obtained by tuning the gate work-function, which ensures the equal transistor strength between P-JLDGFET and N-JLDGFET. Both of the variability and sensitivity induced by the process parameters are also accounted for in developing PDC model. [ABSTRACT FROM AUTHOR]

Sparse code multiple access (SCMA) is a promising nonorthogonal multiple access scheme for the 5G system. In this letter, we introduce a scaling factor (SF) to scale the extrinsic information exchanged between the detector and the decoders to further improve the performance of iterative multiuser receiver (IMR) in SCMA. Appropriate SF is selected by using the extrinsic information transform chart analysis. Simulation results indicate that compared with the standard IMR, the proposed SF aided IMR scheme can achieve obvious gain at the performance and convergence speed under the additive white Gaussian noise and the Rayleigh fading channels. [ABSTRACT FROM PUBLISHER]

With the effects of localized trapped charges on the flat-band voltage, a novel localized-trapped-charge-induced threshold voltage model for the double-fin multi-channel FET (DFMcFET) is presented based on the quasi-3-D scaling equation and minimum bottom-central potential. It is shown that the deep trench of the DFMcFET is superior to the shallow one in respect of reducing the localized-trapped-charge-induced threshold voltage degradation (LTTVD). Besides, the low drain voltage V\mathrm{ ds} , the low trapped charge density Nf , the small damaged zone near the drain side Ls and the thin gate oxide t\mathrm{ ox} are required to resist LTTVD as the normalized damaged zone is increased. The LTTVD can be well controlled by the scaling theory. With the fixed damaged zone and trapped charge density, the allowable minimum channel length can be uniquely determined according to the criterion of scaling factor. In comparison to the conventional FinFET, DFMcFET not only provides more conducting channel, but also suffers less threshold voltage degradation caused by the short-channel effects irrespective of trapped charge polarity. With its computational efficiency and simple form, the model can be easily used for the circuit application for DFMcFET. [ABSTRACT FROM PUBLISHER]

Based on the equivalent channel width and equivalent number of gates, a quasi-3-D scaling length model for the trapezoidal FinFET (TzFinFET) is developed. By accounting for the coupling effects between equivalent double-gate FET and single-gate FET, the scaling length of TzFinFET can be accurately predicted. Besides Fin height, top Fin width, and gate oxide, the scaling length is also sensitive to the inclination angle induced by the process technology. By applying this derived scaling length to the TzFinFET, the subthreshold behavior model including threshold voltage and subthreshold swing can be achieved. Both threshold voltage roll-off and subthreshold swing roll-up can be well controlled by the scaling factor in accordance with the scaling theory. According to the scaling factor, the acceptable minimum channel length that allows the maximum subthreshold degradation can be uniquely determined. The variability of subthreshold characteristics with the process parameter is also taken into account in this paper. [ABSTRACT FROM PUBLISHER]

In this paper, we present a device-physics-based noise margin (NM)/logic swing (LS) model of surrounding-gate (SRG) MOSFET working on subthreshold CMOS logic gates. Based on the device physics and equivalent transistor model, theoretical analysis of the main dc parameters, including LS and NM for SRG MOSFET operating in low-voltage condition, is revealed. It is shown that the device parameters, such as the thick silicon thickness t\mathrm{ si} , thick gate oxide thickness t\mathrm{ ox} , and short channel length Lg , can severely degrade the LS and NM. On the contrary, both the small subthreshold slope \eta and balanced transistor strength S induced by device parameters can suppress the NM and LS degradation efficiently. The required minimum supply voltage V_{\mathrm{ dd,min}} for the subthreshold CMOS logic gate is derived by the criterion of the NM ≥ KT/ q$ to ensure the correct logic gate operation. Being similar to DIBL, both NM and LS degraded by the device parameters can also be uniquely determined and controlled by the scaling factor according to scaling theory. Finally, considerations on the impact of process/voltage/temperature variation are also included for NM/LS behavior analysis. [ABSTRACT FROM AUTHOR]

Based on the device and equivalent transistor model, we present a short-channel-effect (SCE)-degraded noise margin (NM) model for junctionless double-gate MOSFET working on subthreshold CMOS logic gate. The device parameters such as the thick silicon thickness, thick gate oxide thickness, high doping density, and short channel length can severely degrade the NM due to serious SCE. By contrast, both the small subthreshold slope $\eta $ and the balanced transistor strength S can suppress the NM degradation more efficiently. The required minimum supply voltage V_{\mathrm {\mathbf {dd,min}}} for the subthreshold CMOS logic gate is derived by the criterion of the NM larger than thermal noise to ensure the correct logic gate operation. Being similar to drain-induced barrier lowering, allowable NM corresponding to the minimum channel length can also be uniquely controlled and determined by the scaling factor according to the scaling theory. [ABSTRACT FROM PUBLISHER]

A novel unconditionally stable split-step finite-difference time domain (SS-FDTD) method based on an isotropic dispersion finite-difference scheme is introduced. The proposed method reformed the weighting factor and scaling factor of the isotropic-dispersion FDTD for the SS-FDTD method with four substeps, which can generate nearly exact phase velocity for a single frequency. Compared with the conventional four-stage split-step FDTD method, the numerical dispersion error of the new method is significantly reduced even for a large stability factor. The new method is validated by numerical simulations. [ABSTRACT FROM AUTHOR]

To broaden the use of an adaptive resistive algorithm (ARA), we present a 3-D model able to reproduce the experimental magnetic moment loop for a finite-size superconducting strip in a perpendicular field. We also develop the same model by using H-formulation, to strengthen the ARA results. We find that 2-D models computed with the two different approaches, i.e., ARA and H-formulation, provide similar results, and both well compare to approximate analytical solutions. Then, we verify that the computed magnetic moment loop by using either 3-D numerical approaches reproduces the experimental curve, i.e., the magnetic loops of a commercial YBCO-coated conductor sample measured at 5 K. Instead, the 2-D numerical data need a scaling factor to match the experimental ones. The 3-D computations provide support to the hypotheses on the current surface profile that has been used to find the scaling factor. [ABSTRACT FROM PUBLISHER]

An adaptive maximum power point tracking (MPPT) scheme employing a variable scaling factor is presented. An MPPT control loop was constructed analytically and the magnitude variation in the MPPT loop gain according to the operating point of the PV array was identified due to the nonlinear characteristics of the PV array output. To make the crossover frequency of the MPPT loop consistent, the variable scaling factor was determined using an approximate curve-fitted polynomial equation about linear expression of the error. Therefore, a desirable dynamic response and the stability of the MPPT scheme were maintained across the entire MPPT voltage range. The simulation and experimental results obtained from a 3-kW rated prototype demonstrated the effectiveness of the proposed MPPT scheme. [ABSTRACT FROM AUTHOR]

In marching-on-in-degree time domain method of moment, the transient responses are often expanded by a finite number of associated Laguerre functions. There is an error associated in truncating the associated Laguerre function series beyond that what is necessary in the solution process. This error is related to the scaling factor used in the argument of the associated Laguerre functions that actually approximates the unknown temporal variations. A least upper bound of this error is deduced. Based on this bound, one can obtain an optimum scaling factor to minimize this error so that it is guaranteed to be below a certain bound. [ABSTRACT FROM PUBLISHER]

The higher order vector basis functions defined in large patches have been utilized in the numerical solution of integral equations in this paper to sparsify the impedance matrix and relieve the memory pressure. The physical explanation for the sparsification of the impedance matrix is also elucidated. Furthermore, the maximally orthogonalized bases have been applied to improve the condition number of the impedance matrix. The scaling factor was reformed to speed up the iteration convergence in the numerical solution. Finally, the iterative method for sparse matrix equations is applied to improve the solution efficiency. Some numerical results are provided to illustrate the excellent performance both in the sparsification of the impedance matrix and solution efficiency for numerical analysis of the scattering problem. [ABSTRACT FROM AUTHOR]

This paper presents a successful implementation of a fuzzy logic controller structure for switch-mode power-stage dc-dc converters and evaluates experimentally its sensitivity for variable supply voltages and load resistance variations. The optimum topology of the controller structure is determined using experimental tests. An advanced test-bed system is used to evaluate the robustness capacities of the controller under varying loading conditions and input voltage variations. The experiment is performed using a low-cost microcontroller PIC16F877 to verify the design performance over a wide range of operating conditions. The controller shows very interesting tracking features and is able to cope with load changes and input voltage variations. The proposed controller structure is general and can be directly applied to any dc-dc converter topologies. The fuzzy controller structure is compared experimentally with the existing proportional-integral control used in industry. It yields a better dynamic performance without overshoot. [ABSTRACT FROM AUTHOR]

Broadband characterization of any electromagnetic (EM) data (e.g., surface currents, radiation pattern, and network parameters) can be carried out using partial information in the time domain (TD) and the frequency domain (FD). In this hybrid TD-FD approach, one generates the early time response using a TD code at a spatial location and uses a FD code to generate the low-frequency response at the same place. Then, the partial complementary information in both the TD and FD is fit by a set of orthogonal functions and its Fourier transform having the same expansion coefficients. Three different types of functions, namely, Hermite, Bessel-Chebyshev, and Laguerre, have been used for extrapolation. Once the expansion coefficients for these functions are known, the response can be extrapolated either for late times or high frequencies using the initial partial information. The objective of this paper is to explore the conditions under which this hybrid approach yields a stable and accurate solution. We investigate bounds for both the number of orthogonal functions needed to carry out the extrapolation and the scale factors needed to accurately fit the data in time and in frequency. Numerical examples have been presented to illustrate the efficacy of these bounds. It is important to point out that, in this hybrid approach of extrapolation, we are not creating new information but processing the available information in an intelligent fashion [ABSTRACT FROM PUBLISHER]

Traditionally, semiconductor reliability has been estimated from the life tests or accelerated stress tests at the completion of manufacturing processes. Recent research, however, has been directed to reliability estimation during the early production stage through a relation model of yield and reliability. Because the relation model depends on the assumed density distribution of manufacturing defects, we investigate the effect of the defect density distributions on the predicted reliability, for a single-area device without repair and for a two-area device with repair, respectively. We show that for any device, reliability functions preserve an ordering of yield functions. It is also pointed out that the repair capability improves only yield but not reliability, resulting in a large value of the factor that scales from yield to reliability. In order to achieve a reliable device, therefore, we suggest to improve yield and to perform the device test such as burn-in if the scaling factor is large. [ABSTRACT FROM AUTHOR]

The objective of this paper is to generate a wideband and temporal response of three-dimensional composite structures by using a hybrid method that involves generation of early lime and low-frequency information. The data in these two separate time and frequency domains are mutually complementary and contain all the necessary information for a sufficient record length. Utilizing a set of orthogonal polynomials, the time domain signal (be it the electric or the magnetic currents or the near/far scattered electromagnetic field) could be expressed in an efficient way as well as the corresponding frequency domain responses. The available data is simultaneously extrapolated in both domains. Computational load for electromagnetic analysis in either domain, time or frequency, can be thus significantly reduced. Three orthogonal poly- nomial representations including Hermite polynomial, Laguerre function and Bessel function are used in this: approach. However, the performance of this new method is sensitive to two important parameters--the scaling factor lx and the expansion order N. It is therefore important to find the optimal parameters to achieve the best performance. A comparison is presented to illustrate that for the classes of problems dealt with, the choice of the Laguerre polynomials has the best performance as illustrated by a typical scattering example from a dielectric hemisphere. [ABSTRACT FROM AUTHOR]

An accurate and efficient solution method using spectral collocation method with domain decomposition is proposed for computing optical waveguides with discontinuous refractive index profiles. The use of domain decomposition divides the usual single domain into a few subdomains at the interfaces of discontinuous refractive index profiles. Each subdomain can be expanded by a suitable set of orthogonal basis functions and patched at these interfaces by matching the physical boundary conditions. In addition, a new technique incorporating the effective index method and the Wentzel-Kramers-Brillouin method for the a-priori determination of the scaling factor in Hermite-Gauss or Laguerre-Gauss basis functions is introduced to considerably save computational time without experimenting with it. This method shares the same desirable property of the spectral collocation method of providing a fast and accurate solution but avoids the oscillatory solutions and improves the poor convergence problem of the simple spectral collocation method with single domain where regions of discontinuous refractive index profiles exist. Applications to several two- and three-dimensional waveguide structures having exact or accurate approximate solutions are given to test the accuracy and efficiency; all the results are found to be in excellent agreement. [ABSTRACT FROM PUBLISHER]

In this paper, we describe an efficient approach to overcome the need for matrix inversion required in most wired applications encountered in practice. In particular, MMSE equalization based on series expansion to approximate the matrix inversion is addressed. By adjusting a scaling factor, the series expansion is directly optimized according to a fixed order with respect to a system performance criterion. In comparison with previous approaches, the resulting equalizer enables improved BER performance according to a fixed order, in addition to low complexity without the need for a complicated eigenvalue calculation procedure. [ABSTRACT FROM PUBLISHER]

List-based algorithms for. decoding block turbo Codes (BTC) have gained popularity due to their low computational complexity. The normal way to calculate the soft outputs involves searching for a decision code word D and a competing codeword B. In addition, a scaling factor α and an estimated reliability value β are used. In this letter, we present a new approach that does not require α and β. Soft outputs are generated based on the Euclidean distance property of decision code words. By using the new algorithm, we achieve better error performance with even less complexity-for certain BTCs. [ABSTRACT FROM PUBLISHER]

We demonstrate that probability distribution functions (pdfs) such as those of interest in communication theory can be efficiently calculated through a random walk algorithm. To illustrate the procedure, we determine the pdf of polarization-mode dispersion in optical fibers. We find that the technique efficiently samples configurations with extremely low probability for which it converges far more rapidly than the multicanonical procedure. [ABSTRACT FROM PUBLISHER]