نشریه صنایع الکترونیک
سال ششم شماره 1 (پیاپی 20، بهار 1394)

Recently, great advances have been made to improve resolution of synthetic aperture radar (SAR) images. Numerous studies have been conducted on segmentation of SAR images for developing and updating geographical information. The present paper proposes a fuzzy cellular automata algorithm for segmenting SAR images. This theory is a combination of cellular automata and fuzzy rules to develop a model called fuzzy cellular automata. In this paper, 8-tuple Moore neighborhood has been used. Three variables including primary cells, immune status of neighboring cells and gray-level of neighboring cells were investigated in eight different directions Moore and fuzzy rules have been imposed on them. Then, the results have been tested on two sets of images. The first is a set of optical and simulated SAR images. The images were first segmented by FCA algorithm. Then, the results were compared with the results of GA and AFS algorithms. The error rates of previous FCA and the proposed FCA have been calculated. The second set includes real SAR images. After segmenting by FCA algorithm, the results were compared with the results of GA, AFS, ABC, histogram-based thresholding algorithm and previous FCA algorithms. The results show that the proposed method is more appropriate for segmenting SAR images because of higher accuracy and less error rate than other methods.

Local Vertical Generator is required for starting the imaging operation of the camera in spin satellites. When the satellite spins,this system should sense the earth and generate the starting pulse of the imaging operation for telemetry and camera. In the other word, this system active the imaging payload and telemetry system in appropriate time. To generate starting pulse,it used of infrared (IR) radiation from the Earth. Infrared wavelengths is from to which is used in satellite earth sensors. Optic's glass is made of germanium, which is transparent in this region. Germanium is readily machinable, and its low chromatic dispersion allow the use of simple and uncorrected lenses in IR imaging systems. In this paper design, and implementation of local vertical generator based on pyroelectric detector and its electronic for a spin satellite in attitude of 800 Km is presented.

This paper presents a high throughput decoder for QC-LDPC codes. In the proposed architecture, based on layered min sum decoding, a novel technique for simultaneous process of rows and columns is presented, that reduced the number of clock cycles in per iteration and as result the throughput is increasing. The proposed decoder is presented for any code length (576:96:2304), in code rate 1/2 and 7-bit quantization in 802.16e standard. Based on proposed decoder, QC-LDPC decoder is synthesized for code length 2304, on 130 nm CMOS technology by Synopsys Design Compiler. The obtained results in the operating frequency of 100 MHz and 10 iterations show that the maximum throughput is 198 Mb/s and total power consumption of 156.39mW and chip area of 5.09 mm2.

To manage congestion in a computer network congestion control algorithms are used. Studies so far show that in homogeneous networks, TCP-Vegas in many cases, acts better than TCP-Reno. But when both algorithms of Vegas and Reno are being used in the Internet, Reno acts better than Vegas. For this reason, there is no incentive for operating systems to use Vegas as the default transport layer protocol. In this article, an improved Vegas has proposed which is consistent with Reno and when it is competing with Reno, it can get a fair share of network resources. Unlike TCP-Vegas which uses the fixed parameters α and β, the proposed algorithm, determines these parameters according to network conditions and in a dynamic way. The proposed algorithm is being compared with original Vegas and other improved Vegas algorithms like, Vegas-A and CODE TCP. Simulation results show that the proposed algorithm competing with Reno, compared to other improved algorithms, achieves a more equitable share of the bandwidth and has a higher throughput. Furthermore, proposed algorithm also preserves the good qualities of Vegas algorithm.

This paper presents a CMOS ultra-wideband (UWB) gm-boosted common-gate low noise amplifier (LNA) based on an active inductor to improve the noise specification and area consumption of the circuit. A common-source stage used in the feedback path boosts the gm of the LNA. Furthermore, the large, passive, on-chip inductor needed for the LNA design is replaced by an active inductor which decreases the chip area, significantly. The proposed structure is designed and simulated in a 0.18 µm standard CMOS process. The results reveal that the proposed LNA has reached to a flat forward gain (S21) of 11.85±0.85 dB, reverse isolation (S12) of less than -56.1 dB, input reverse loss (S11) of less than -9.64 dB, and noise figure (NF) of 4.6-4.9 dB over the entire frequency band of 3.1-10.6 GHz, while the total power dissipation for a 1.8 V supply voltage is 13.6 mW.

Tracking of flying objects via passive sensors is one of the basic requirementsfor surveillance and control.The uses of radar systems are expensive.In this paper the image is used as reference for locates the flying object.Proposed system consists of an infrared camera and an eye safe laser range finder which are mounted on a pan/tilt to track a flying object.The tracking data are sent to the trajectory analysis system which calculate the target's trajectory in real time.Tracking algorithm which is used in the proposed system improves the errors of other methods and can be implemented easily and has a good speed Automatic landing system is necessary for safer landing of a UAV.A more events of crash happen at the landing phase because of inexperience of pilots or sudden changes in the weather such as wind,rain.Automatic landing system requires continuous and precise positioning information.So, positioning device is one of the key factors of this system.Proposed system use image processing techniques for tracking of the UAVs in an automatic landing system.This system are inexpensive,passive and robust to jamming In this paper we propose an automatic landing system with accuracy of less than one meter which has covered many of the disadvantages of other methods and has a very lowcost compared to other methods Experiments show that the algorithm in the worst case lose about5% of the frames which does not harm auto landing system.These experiments were performed on real data and algorithm achieved accurate performance in the presence of cloud and background clutter.

In recent years, spoofing is known as a perceived emerging threat to GPS receivers. The spoofing attack result is large navigational solution errors in the unsuspecting user with potentially serious consequences. Since the spoofing signal imitates the authentic one, the receiver cannot detect the presence of that. Therefore, detection and mitigation of spoofing is more difficult than other interferences. In this paper, we try to study all of proposed anti-spoofing approaches for single frequency GPS receivers. At first the general process of each technique is described summarily, then its challenges, advantages and disadvantages are pointed. Finally, a novel and applicable idea based on Neural Network (NN) is introduced for spoofing compensation. In that we use a back propagation algorithm in range domain for estimation and compensation of tracking code and carrier error due to spoofing attack. In this way, by utilizing NNs we can mitigate spoofing error with an average of 82% and a tolerance of 2%.

Nowadays, with the recent advances in micro-electro-mechanical systems (MEMS) fabrication technology, micromechanical resonators are used widely in wireless communication and navigation systems. In this paper, a micromechanical rectangular-plate resonator is introduced to increase the electromechanical coupling coefficient and enhanced the electrical performance of the micromechanical beam resonators. Moreover, the micromechanical rectangular-plate resonator with four conventional support beams is proposed to suppress the spurious mode effect. With regard to the dominated quality factor by anchor loss in some important applications including oscillators, electrical filters and gyroscopes, the closed-form expression is obtained for anchor loss quality factor in the plunging-mode vibrations of micromechanical rectangular-plate resonator. The findings are validated by comparing with experimental data. As far as there is an acceptable match between the analytical and experimental results, the proposed model is confirmed. According to the results, a novel T-shaped support beam design is proposed to enhance the anchor loss quality factor in the plunging-mode vibrations of micromechanical rectangular-plate resonators. In fact, the main purpose of this paper is the introduction of a novel design for support beams in micromechanical rectangular-plate resonators to achieve high quality factor, low motional resistance and low spurious modes. For this purpose, the two support beams are replaced with four T-shaped support beams. The results show that the anchor loss quality factor at the same resonant frequency is enhanced about 1.65 times. Moreover, the anchor loss quality factor at the constant resonant frequency increases with decreasing the width and increasing the length of T-shaped support beam.