فصلنامه روشهای هوشمند در صنعت برق
پیاپی 25 (بهار 1395)

Videos are made up of a temporal sequence of frames and are projected at a proper rate to create the illusion of motion. This means that there exists a high correlation between adjacent temporal frames so that when projected at a proper rate, smooth motion is seen. Correlation between adjacent temporal frames is called interframe correlation. In order to decode compressed video bit stream uniformly by various platforms and devices, the bit stream format must be predefined. Thus, there must be a standard for a video compressor, which will enable all standard-compliant compressed video data to be decoded anywhere. The goal is to propose a new video compression algorithm based on wavelet transform and neural networks. Using wavelet transform leads to factorization in temporal as well as spatial domain. The goal in this paper is to achieve a compression algorithm which would be faster and has more compression ratio. Neural networks are used for prediction which is one of the most important functions in any video compression scheme. Furthermore, the proposed algorithm is compared with MPEG standard. Simulation results show the befits of using wavelet transform which reveal that the proposed algorithm is faster and has better performance in some aspects compared to MPEG standard. The video which obtained from proposed algorithm has acceptable in human visual and since it needs less than space for storing, it is suitable for portable devices.

In this paper, A compact multiple-input-multiple-output (MIMO) antenna with a small size of 26×31mm2 is proposed for portable ultrawideband (UWB) applications. The antenna consists of two square-monopole antenna with microstrip-fed by a 50- Ω printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, two long ground stubs are added to the ground plane on the other side. Simulation is used to study the antenna performance in terms of reflection coefficients at the two input ports, coupling between the two input ports, radiation pattern, realized peak gain, efficiency and envelope correlation coefficient. Results show that the MIMO antenna has an impedance bandwidth ( for S22

In this paper, the system control design problem twin rotors helicopters Unmanned Aerial Vehicles (UAV) in three dimensional space Without uncertainty based on the dynamic adaptive control is studied. the adaptive Dynamic surface control approach complexity explosion problem in non-linear control step back or backstepping method [45] using the First-order filters removed. The first helicopter dynamic equations and functions are examined. Then, the Dynamic surface control techniques by compare non-linear control technique back stepping [45] is checked and the system is simulation by both techniques adaptive Dynamic surface control and nonlinear control back stepping method. The proposed adaptive dynamics surface nonlinear control method approach is able to guarantees that all the signals in the closed-loop system are asymptotically stable for all initial conditions and you can also choose appropriate design parameters of the system output converges to a small neighborhood of origin ensured . Finally, simulation results are presented, showing the effectiveness of control methods are given.

Nowadays one of the specialized and important issues in construction of marine floats is to design the communication telecom system between them. Always this issue has been posed how to establish an appropriate communication for floats in different distances and different weather conditions in the sea. Due to the restrictions, such as equipment size, weight bearing on the floats has always existed.One of the main parts of telecom communication system is antenna.The main problem, use antennas and Towers various in floats, As required, waves with different wavelength sand different routes to be published. If the antenna can be designed with small dimensions and possible,wide frequency range and also covered omni-directions, the problem has been mentioned above somewhat is resolved. The purpose of this paper is to design and simulate of a sample of integration broadband antenna and omni-directional, that resolve About restrictions above and Integration of two antennas in frequency range of VHF/UHF=150-450MHZ and HF=3-30MHZ with characteristics of 50ohm input impedance, linear vertical polarization, VSWR

Abstract: This paper presents the design and simulation of low-noise amplifier (LNA) with .18CMOS technology in 2.4GHz frequency addressed, the process HSPICE RF simulation software has been done. Using cascode structure leads to lower power consumption with higher voltage gain and power gain. Matching network was used in the design of this circuit has a very good improves on the parameter S11 and allows to have a good control on the real part of the impedance of circuit by appropriate selection of matching network in input and output. By right choosing of circuit elements in this structure can have an approllllojjpriate compromise among the circuit parameters like noise figure, gain, power and stability to reaching noise figure (NF), input reflection coefficient and low power consumption with high gain. In the 2.4GHz frequencyl with 1.8V supply voltage and 1.9 mW power consumption, the circuit parameters are: NF=1.21dB, Av=28.dB, S11=-29.25dB, S12=-35.49dB, S21=18.46dB