Because of refraction of the incoming wave in the radar-guided interceptors, the radome can cause large miss distance and even having a destabilizing effect on the guidance system. On the other hand, the radome imposes an unwanted feedback that is not similar to the conventional feedback loops, in which output must follow a desired control signal. In this paper, the destructive effect of radome in guidance loop stability and performance is analyzed at first. Then, proposing a virtual integrator operator, the problem is transformed to a conventional tracking control problem so that the performance indexes can be defined in control aspect. Regarding the parametric uncertainty of the radome slope, µ-synthesis approach is used to design a robust compensator. Simulation results and stability analysis show that the designed compensator improves the guidance system performance in the presence of the radome, while the stability is guaranteed.

This paper presents a dual-active capacitance in reversed nested Miller COMPENSATION (DACRNMC) TECHNIQUE for low-voltage and large capacitive load amplifiers. The frequency bandwidth of the DACRNMC amplifier has been improved due to the usage of active COMPENSATION capacitors. The amplifier's die area is reduced in compare to the existing TECHNIQUEs in the RNMC scheme. The architecture also generates two left half plane zeros to increase the phase margin. The simulation for the proposed DACRNMC amplifier with a 0.18μm standard CMOS process reveals a unity gain bandwidth of 17.4MHz and phase margin of 64 degrees , while 500 pF load is driven from a single 1.5 V power supply.

Friction is a nonlinear phenomenon which has destructive effects on performance of control systems. To obviate these effects, friction COMPENSATION is an effectual solution. In this paper, an adaptive TECHNIQUE is proposed in order to eliminate limit cycles as one of the undesired behaviors due to presence of friction in control systems which happen frequently. The proposed approach works for nonlinear dynamic and static friction models and is applicable to a wide range of different mechanical systems. It is also applied to a simple inverted pendulum on a cart as a highly nonlinear under-actuated system. A nonlinear optimal controller based on the approximate solution of Hamilton-Jacobi-Bellman partial differential equation is designed to fulfill our control objectives and achieve preferable performance compared to those of the linear optimal controllers. It causes to have more accuracy in system's response and positioning in the presence of friction. Simulation result approve the effectiveness of both the presented TECHNIQUE and controller.

Spoofing could pose a major threat to Global Positioning System (GPS) navigation, so the GPS users have to gain an in-depth understanding of GPS spoofing. Since spoofing attack can influence position results, spoof COMPENSATION is possible through reducing position deviations. In this paper, a novel processing TECHNIQUE is proposed and the wavelet transform is used to eliminate the impact of spoofing on the stationary GPS receivers. We assumed that the spoofing attack was immediately detected, and then the position residuals of the last authentic and new spoofing signals were passed to the statistic wavelet transform at the first level. By denoising in the next step, position deviations due to the spoofing attack can be extracted. Then, the estimated position solution of the received signal is corrected. Finally, the receiver coordinates are calculated by averaging the corrected positions. For validation of the suggested algorithm, five different data sets are investigated. We mitigated the spoofing in all data sets more than 93%. The test results show that the proposed TECHNIQUE supremely improves the performance of the GPS receiver and attenuates the spoofing effect.

Aims The use of intrauterine devices (IUDs) has been one of the most effective, the safest and cost-effective methods for preventing pregnancy, for a long time. However, some complications have been reported for IUDs. The complications may be reduced by using a specific TECHNIQUE for placement of IUD. The objective of this study was to introduce the rotating withdrawal TECHNIQUE for the first time, which was investigated to reduce the complications of IUD insertion. Materials & Methods This historical cohort study was conducted on 1199 females who referred to Sarem Medical Center for IUD insertion from 1984 to 1995. After primary examinations, IUD was inserted by rotating withdrawal TECHNIQUE. The subjects were followed up for 2 years. Findings Displacement was observed just in 20 cases (1. 67%). All of them were seen in the first month after placement. For these cases, IUD insertion was done again. After the second replacement, displacement was observed in 4 cases (0. 035%) after one month. Therefore, it was recommended to them to use another preventive method. There was no pregnancy or displacement in the other cases during 2 years. Conclusion The rotating withdrawal TECHNIQUE can minimize the pregnancy rate when IUD is used. In addition to the type and quality of IUD, insertion method of IUD can increase its effectiveness.

In this paper, we analyze a distributed amplifier based on input/output attenuation COMPENSATION. The analysis is carried out for a HEMT transistor; and a constant-k section filter is used to calculate the amplifier’s characteristics such as attenuation factor, phase constant and gain. The proposed design approach enables us to examine the tradeoff among the variables, which include the type and the number of devices, and the impedance and cutoff frequency of the lines. Consequently, we arrive at a design which gives the desired frequency response with significant bandwidth enhancement of around 70% with about 10% increase in circuit size. The simulation carried out by Advance Design System (ADS) software. Excellent agreement is shown when the theoretically predicted response of a typical amplifier is compared with the result of the computer-aided analysis (simulation).

In this paper, a new hybrid intelligent method is presented for detecting the bearing faults in the various rotating speeds. The vibration signals are collected in four conditions, including the normal state, the faulty inner race, the faulty outer race, and the faulty bearing element. Firstly, twenty-two statistical features in the time domain and four frequency features, three Wavelet packet decomposition (WPD), and the first five intrinsic mode functions obtained by the empirical mode decomposition (EMD) are extracted from the original signal; finally, the feature vector for each signal sample has 424 features. However, in the high dimensional feature matrix, there may exist the insensitive features to the presence of defects. Therefore, in this study, the COMPENSATION distance evaluation TECHNIQUE (CDET) is used to select the optimal features. Then, the selected features are used as the inputs of the support vector machine (SVM) classifier to diagnose the bearing conditions. In the CDET method, there is a threshold indicator that plays a decisive role in choosing the desired attributes. Also, the SVM method has some parameters that need to be set during the fault detection process. Therefore, the particle swarm optimization (PSO) algorithm is used to determine the optimal threshold in the CDET method and the optimal SVM parameters, so that the prediction error of the bearing conditions and the number of the selected features are minimized. The obtained results demonstrate that the selected features are well able to differentiate between different bearing conditions at various speeds. Comparing the results of this paper with other fault detection methods indicates the ability of the proposed method.

In this paper, a new method for extending and relaxing the noise-coupling (NC) TECHNIQUE is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling TECHNIQUE is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.