Equalizer Design Research Articles

Bayesian Adaptive Randomization and Trial Monitoring with Predictive Probability for Time-to-event Endpoint.

There has been much development in Bayesian adaptive designs in clinical trials. In the Bayesian paradigm, the posterior predictive distribution characterizes the future possible outcomes given the currently observed data. Based on the interim time-to-event data, we develop a new phase II trial design by combining the strength of both Bayesian adaptive randomization and the predictive probability. By comparing the mean survival times between patients assigned to two treatment arms, more patients are assigned to the better treatment on the basis of adaptive randomization. We continuously monitor the trial using the predictive probability for early termination in the case of superiority or futility. We conduct extensive simulation studies to examine the operating characteristics of four designs: the proposed predictive probability adaptive randomization design, the predictive probability equal randomization design, the posterior probability adaptive randomization design, and the group sequential design. Adaptive randomization designs using predictive probability and posterior probability yield a longer overall median survival time than the group sequential design, but at the cost of a slightly larger sample size. The average sample size using the predictive probability method is generally smaller than that of the posterior probability design.

Effects of HTS Tape Arrangements on AC Loss in Self-Shielding DC HTS Cable With AC Ripple Current

Critical current and ac loss of high-temperature superconducting (HTS) tapes are two important factors for the application of ac HTS power cables. Generally, the current in the dc HTS cable is a combination of main dc current and ac ripple current due to the use of rectifier. The ac ripple current distribution without proper adjusting would be nonuniform in each layer especially when the dc HTS cable layer increases; it may lead to high ac loss and poor transmission capacity. In order to understand the ac ripple current sharing among dc HTS cable layers, the inductance matrix of the cable layers was deduced based on the geometry configuration of a self-shielding dc HTS cable. In this paper, in addition to the uniform current design principle, a self-shielding dc HTS cable is also designed with the HTS tape arrangements of each layer optimized by taking the ratios of ac ripple current amplitude to critical current in each layer as equal for minimizing the ac loss. According to the design configuration and deduced inductance matrix, current in each layer and ac loss are calculated. The results show that it is necessary to use the optimized design in the dc HTS cable design and the equal ratio design is better than the uniform current design.

Energy Leakage and Characteristic Analysis of HMSIW and Implement in Multi-layered Structure Equalizer Design

The phase constant and attenuation constant of half mode substrate integrated waveguide (HMSIW) are calculated using an improved quicker multi-line method in this paper. A mathematical method is proposed to analyze the energy leakage of HMSIW theoretically. The radiation and leakage character of electromagnetic field at open face of HMSIW is different with different relative permittivity. An equalizer loaded multi-layered HMSIW resonant cavities is proposed based on the energy leakage excitation without external coupling structure. Compared with the other planar circuits, these structures have superiorities of small size, simple structure, low loss and high Q, suitable for the miniaturization development, and are easily integrated with other circuits. Furthermore, this proposed equalizer has a simpler design procedure than other HMSIW equalizers without resonant frequency deviation.

A 150 m/22.5 Gbaud PAM4-based FSO link

A 22.5 Gbaud four-level pulse amplitude modulation (PAM4) signal applied to free-space optical link was experimentally tested using a 3 dB laser at a bandwidth of 10 GHz to directly modulate the 22.5 Gbaud PAM4 signal via injection-locked technology. Through the design of pre-compensation and equalizer for signal quality improvement, a successful transmission of 150 m in free space was achieved with good real-time bit error rate performance and clear eye diagrams (three independent eye diagrams).

Single-Carrier Frequency-Domain Equalization With Hybrid Decision Feedback Equalizer for Hammerstein Channels Containing Nonlinear Transmit Amplifier

We propose a nonlinear hybrid decision feedback equalizer (NHDFE) for single-carrier (SC) block transmission systems with nonlinear transmit high power amplifier (HPA), which significantly outperforms our previous nonlinear SC frequency-domain equalization (NFDE) design. To obtain the coefficients of the channel impulse response (CIR) as well as to estimate the nonlinear mapping and the inverse nonlinear mapping of the HPA, we adopt a complex-valued (CV) B-spline neural network approach. Specifically, we use a CV B-spline neural network to model the nonlinear HPA, and we develop an efficient alternating least squares scheme for estimating the parameters of the Hammerstein channel, including both the CIR coefficients and the parameters of the CV B-spline model. We also adopt another CV B-spline neural network to model the inversion of the nonlinear HPA, and the parameters of this inverting B-spline model can be estimated using the least squares algorithm based on the pseudo training data obtained as a natural byproduct of the Hammerstein channel identification. The effectiveness of our NHDFE design is demonstrated in a simulation study, which shows that the NHDFE achieves a signal-to-noise ratio gain of 4dB over the NFDE at the bit error rate level of $10^{-4}$ .

Robust equalizer design for adaptive room impulse response compensation

Adaptive room equalization aims at providing a listener with an audio experience, which is very close to the original audio signal. The equalizer, which is an adaptive filter, compensates for the disturbance in the audio signal contributed by the impulse response of the room. One of the most popular algorithms employed for the design of an adaptive room equalizer is the filtered-x improved proportionate normalized least mean square (Fx-IPNLMS) algorithm. IPNLMS is effective in equalizing sparse as well as non-sparse room impulse responses. However, Fx-IPNLMS is not robust to strong disturbances picked up by the microphone used in the equalization process and the algorithm may even diverge in such scenarios. With an objective to overcome this limitation of IPNLMS based adaptive room equalization schemes, a robust Fx-IPNLMS algorithm has been developed in this paper. The new algorithm has been shown to provide robust room equalization and thus an enhanced audio experience.

A New Turbo Equalizer Conditioned on Estimated Channel for MIMO MMSE Receiver

In this letter, we propose a new equalization scheme based on minimum mean-square error (MMSE) criteria with a channel estimation error. Different from the existing work on linear MMSE receivers, we consider both the a priori information and channel estimation error in the equalizer design, and re-derive the soft output extrinsic information used for the channel decoder. Conditioned on the estimated channel, we developed the new autocorrelation and covariance matrix of the received vector, which are used to derive the equalizer coefficients. One of our major contributions of this letter is a general expression of the MMSE-based turbo equalization to account for both the channel estimation error and the a priori information, which is not presented in the literature. Simulation results show that significant performance improvement can be achieved with the proposed turbo equalizer.

Study on the design method of equal strength rim based on stress and fatigue analysis using finite element method

Wheels are important safety components in the vehicle driving system. Automobile lightweight is the direction of the modern automobile development. In this article, steel wheel lightweight was studied. The equal strength design of rim was used to reduce the weight of the wheel. Stress analysis of the wheel was studied using UG/Nastran. A professional software WheelStrength was used to predict the radial and cornering fatigue lives of the wheel. Sheet stamping process was set up to analyze the interference fit between the disk and the rim. The assembly was simulated by axisymmetric finite element method. After calculation and analysis, the stress distributions and fatigue lives for rim under different load cases have been found. The thicknesses of wheel rim bead and the interface between rim and disk cannot be reduced. Stress and fatigue simulation results were compared using different thicknesses of the optimized region. It was found that the best thickness of the optimized region was 1.5 mm. Spinning was used to form the flared preform. The thickness of the rim after spinning and rolling forming agreed well with the simulation. The results of fatigue tests indicated that the lightweight wheel met the design requirement. The weight of the rim was reduced by about 14%.

How do high school students solve probability problems? A mixed methods study on probabilistic reasoning

ABSTRACTWhen studying a complex research phenomenon, a mixed methods design allows to answer a broader set of research questions and to tap into different aspects of this phenomenon, compared to a monomethod design. This paper reports on how a sequential equal status design (QUAN → QUAL) was used to examine students’ reasoning processes when solving probability problems. A select clustered sampling resulted in the inclusion of 168 high school students in a first, quantitative phase, in which a questionnaire was used to assess how they solved probability problems. This questionnaire included probability items that were based on the outcome orientation, the representativeness misconception, and the equiprobability bias. In a second, qualitative phase, 18 students who were purposefully sampled from the first research phase were interviewed in order to conduct an in-depth study of their probabilistic reasoning processes. In this paper, we illustrate and discuss how several mixed methods research purposes were realized throughout our study: development, expansion, and initiation.

FSRFT—Fast Simplified Real Frequency Technique via Selective Target Data Approach for Broadband Double Matching

This brief introduces a broadband double-matching (DM) solver called fast simplified real frequency technique (FSRFT). FSRFT is essentially a greatly accelerated variant of the well-known classical simplified real frequency technique (SRFT). The basic idea that turns the classical SRFT into a “fast” SRFT relies on two main approaches: the selective target data approach (STDA) and the constraint optimization approach (COA). STDA constructs an optimization target data set formed of only critically selected target data whose element number is equal to or slightly greater than the order of the system unknowns n plus 1, n + 1. In order to exhibit speed performance comparison between SRFT and FSRFT, an example design is considered. An exemplary DM problem, dealing with an n = 6th order low-pass Chebyshev- type equalizer design to match the given generator and load impedances, has been solved by SRFT within 29 s using 90 target data in a typical computer-e.g., Intel 2.20-GHz i7 CPU with 8-GB RAM. On the other hand, the same problem has been solved by the newly proposed FSRFT within only 0.6 s using only n + 1 = 7 critically selected target data in the same computer. FSRFT introduced herein works in any domain, i.e., lumped, distributed, and mixed.

Joint transceiver FIR filter design for multiuser MIMO channel shortening equalization and full equalization using channel duality

Joint transceiver FIR filter design for multiuser MIMO channel shortening equalization and full equalization using channel duality

Research on Lightweight Design of Automobile Lower Arm Based on Carbon Fiber Materials

Based on the principle of lightweight design, a method of using carbon fiber reinforced composite instead of traditional metal materials to design automobile carrier can be proposed. The method uses the equal stiffness design principle of the composite material parts to lay out the design of the carbon fiber parts, including the application of the laying angle and the thickness of the laying layer in design. Through the analysis of the actual working conditions of the lower arm, the stress and boundary conditions are obtained. After the design of the stiffness, the geometrical topology of the lower arm is further optimized. Finally, the lower arm of the carbon fiber not only met the performance requirements, but also to a certain extent, achieved the purpose of lightweight.

Brisk Mechanized of OSTE Polymer RF-Mems Components

This paper reports the first RF-MEMS component in OSTE polymer. Three OSTE-based ridge gap resonators were fabricated by direct, high aspect ratio, photostructuring. The OSTE polymer's good adhesion to gold makes it suitable for RF-MEMS applications. The OSTE ridge gap resonators differ in how they were coated with gold. The OSTE-based devices are compared to each other as well as to Sibased, SU8-based, and CNT-based devices of equal design. The OSTE-based process was performed outside the cleanroom, and with a fast fabrication process (∼1 h). The OSTE-based device performance is on par with that of the other alternatives in terms of frequency, attenuation, and Q-factor.

PENGEMBANGAN KURIKULUM PENDIDIKAN KESETARAAN

The purpose of this research is to reveal how policy-makers and curriculum developers to design educational curriculum equality. This type of research is qualitative descriptive. The main data were collected by questionnaires and group discussions terpumpun. Data were analyzed using descriptive statistics, namely the depiction of the data with the pattern description. The study was conducted in November 2015 until June 2016, with a sample of teachers and education staff of three learning centers. The results showed. First, policy makers and developers are still putting that designing and realizing equality education curriculum has not made a top priority, but are waiting for formal education first. Second, policy makers and developers have not presenting concrete policy markers related complexity and context of the fundamental aspects of reality which represents the common interests of citizens of the nation that terejawantahkan in the curriculum as a tool tread life. Third, the design of educational curricula equality has not equip knowledge and competence as a prerequisite to work and also not strong attitudes toward integrity, hard work, discipline, mutual cooperation, independence, nationalism and specialized skills to solve the problem of life. Fourth, equal education curriculum design not describe the instruments to face the problem of dropouts and solve socio-economic problems oriented towards life skills in order to enter the life.

초고주파용 선형 이득 등화기 설계 및 제작

초고주파용 선형 이득 등화기 설계 및 제작

An efficient and robust method to determine the optimal tap coefficients of high speed FIR equalizer

The FIR equalizer is a common way to compensate for the effect of ISI in high speed data transmission. One key issue for the FIR equalizer design is to find the optimal tap coefficient (TC) set. In this work, the TC search is formulated as an eye-diagram based global optimization problem and an efficient and robust multi-start point (MSP) optimizer is developed and applied to determine the optimal TC set. To guarantee a robust optimization procedure, an objective function based on the eye diagram is studied. It proves that a 330x speedup is provided by the proposed method as compared with the Monte Carlo method. With the proposed method, the optimal design point of the equalizer can be further estimated.

A computer tool for a minimax criterion in binary response and heteroscedastic simple linear regression models

Background and objectiveBinary response models are used in many real applications. For these models the Fisher information matrix (FIM) is proportional to the FIM of a weighted simple linear regression model. The same is also true when the weight function has a finite integral. Thus, optimal designs for one binary model are also optimal for the corresponding weighted linear regression model. The main objective of this paper is to provide a tool for the construction of MV-optimal designs, minimizing the maximum of the variances of the estimates, for a general design space. MethodsMV-optimality is a potentially difficult criterion because of its nondifferentiability at equal variance designs. A methodology for obtaining MV-optimal designs where the design space is a compact interval [a, b] will be given for several standard weight functions. ResultsThe methodology will allow us to build a user-friendly computer tool based on Mathematica to compute MV-optimal designs. Some illustrative examples will show a representation of MV-optimal designs in the Euclidean plane, taking a and b as the axes. The applet will be explained using two relevant models. In the first one the case of a weighted linear regression model is considered, where the weight function is directly chosen from a typical family. In the second example a binary response model is assumed, where the probability of the outcome is given by a typical probability distribution. ConclusionsPractitioners can use the provided applet to identify the solution and to know the exact support points and design weights.

Per-Subchannel Joint Equalizer and Receiver Filter Design in OFDM/OQAM Systems

Orthogonal-frequency-division-multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) based multicarrier system achieves better spectral efficiency in comparison with the widely used multicarrier OFDM system. However, the OFDM/OQAM system suffers from intersubchannel interference and intersymbol interference in frequency-selective channels, which cause poor bit error rate (BER) performance. To overcome these challenging issues, in this paper, we propose a per-subchannel joint equalizer and receiver filter design method based on maximizing signal-to-interference-plus-noise ratio (SINR) of each subchannel. An iterative two-step algorithm is developed to design equalizer and receiver filter jointly. At the first step, by assuming that the receiver filter impulse response is identified, an equalizer is designed for each subchannel by maximizing its SINR. At the second step, by assuming that the channel and equalizer impulse responses are known, the SINR of each subchannel is derived based on the receiver filter impulse response coefficients. In this way, the receiver filter of each subchannel is designed independently by maximizing the SINR of that subchannel. The convergence of the proposed iterative design algorithm is proven and also the designing procedure is extended for multi-input-multi-output channels. Simulation results show that the proposed OFDM/OQAM system, in addition of its superior bandwidth efficiency, significantly achieves better performance in comparison with the OFDM system. Moreover, the convergence speed of the iterative SINR maximization algorithm is evaluated by numerical assessments under different scenarios.

A short note on equal peak design for the pendulum tuned mass dampers

Pendulum tuned mass dampers (PTMDs) are used to passively mitigate the vibrations of tall structures and buildings. The main objective of this short note is to introduce analytical formulae for the optimum design of the linear PTMD coupled to an undamped primary system. Den Hartog's equal peak method is applied to derive the optimum design. With the mass ratio between the primary system and the PTMD, the optimum length and optimum damping of the pendulum are calculated. The formulae are presented in both dimensional and non-dimensional forms and are simple to apply in real applications. It is also shown that the vibration mitigation performance of the proposed optimum design precisely matches the results obtained by numerical optimisation techniques.

An Equalizer With Controllable Transfer Function for 6-Gb/s HDMI and 5.4-Gb/s DisplayPort Receivers in 28-nm UTBB-FDSOI

A multistage continuous-time linear equalizer (CTLE) design with a controllable transfer function is presented. The entire frequency range of interest, from dc to gain roll-off frequency, is divided into six regions, and the transfer function in each region is independently matched to be the inverse of the channel transfer function. The equalizer is used for 6-Gb/s data transfer per channel for high-definition multimedia interface (HDMI) 2.0 receiver and 5.4-Gb/s data transfer per channel for DisplayPort (DP) receiver designs. Fabricated in a 28-nm ultrathin body and buried oxide fully depleted silicon-on-insulator technology, the 0.06-mm2 CTLE consumes 30 mW to achieve up to 28-dB peaking. The entire receiver channel occupies 0.21 mm2, consumes 55 mW, and achieves a power efficiency of 9.2 pJ/bit at 6 Gb/s. This design achieves a jitter tolerance of 0.7 unit interval (UI) up to 10 MHz for HDMI and 0.42 UI up to 100 MHz for DP, which is better than their respective specifications.