IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING

In this paper, the fractal concept is used in the linear array antenna design to obtain multiband operation and reduced size. MATLAB programming language version 7.2 (R2006a) is used to simulate the fractal linear array antenna and their radiation pattern. Fractal Cantor linear array antenna of array pattern of 101 has been designed at a frequency of 2700 MHz with uniform and non uniform amplitude distribution. The performance of this array has been simulated. It is found that it operates at frequencies 2700 MHz, 900 MHz, 300 MHz, and 100 MHz. Two proposed models of Cantor linear array antenna having array patterns of 11011 and 1010101 are presented with uniform and non uniform amplitude distribution. The performance of these arrays has been simulated. The resulting frequency behavior is found that it operates at frequencies 2700 MHz and 540 MHz for the first model (11011) and 2700 MHz and 386 MHz for the second model (1010101). The frequencies have been selected in the VHF and UHF bands have been used in many applications in communication systems such as global system mobile (GSM), wireless local area network (WLAN), worldwide interoperability for microwave access (WIMAX) .... etc.

Lab VIEW (Laboratory Virtual Instrument Engineering Workbench) is gaining its popularity as a graphical programming language especially for data acquisition and measurement. This is due to the vast array of data acquisition cards and measurement systems which can be supported by LabVIEW as well as the relative ease by which advanced software can be programmed. One area of application of LabVEW is in the measuring and analyzing of radial temperature distribution. This paper describes a LabVIEW based data acquisition and analysis developed specifically for radial temperature distribution. The temperature is simultaneously measured and displayed.

The coherent optical heterodyne receiver for a solid-state laser based on Optical Phase- Locked-Loop (OPLL) is investigated. The phase shift effect of IF-stage at the output laser frequency is proposed under noise terms conditions: shot noise and the components of laser frequency noise. Integral expressions in terms of delay-bandwidth product œητɖ are derived to specify the optimal loop bandwidth required to minimize the phase error variance for various values of carrier-to-noise ratios (A²/No) in dB-Hz. The obtained results reveal that the synchronization limits of 0.25 (rad) maintain the standard deviation of phase error to be less than 10° and BER of 109 for ζ=0.707. Further,mon the normalized degradation factor (Amin) of the total phase error variance is also determined to be less than 1.6.

In this paper, a 128-bit block cipher B-R encryption algorithm is proposed which is an evolutionary improvement of 64-bits Blowfish designed to meet the requirements of the Advanced Encryption Standard. It is compact, speedy, simple and easy to understand. It is a Feistel network, iterating a simple encryption function 16 times and the key can be any length up to 128 bytes. The B-R reduced the memory requirement by using two S-boxes each of which of size 259 bytes instead of four S-boxes each of size 1024 bytes in Blowfish algorithm,so that the total size of S-box of B-R is 518 bytes while the size of S-box of Blowfish is 4096 bytes, without compromising security. Using several techniques will increase the security of B-R algorithm. Block size and key length were increased and RC6 as complex function was used after the F-function to avoid a symmetric to the output of S-boxes A desirable property of an encryption algorithm is that a small change in either the plaintext or the key should produce a significant change in the ciphertext. This is so called Avalanche Effect. An average of Avalanche Effect of proposal B-R is about 65.42857 % if only one bit in the key is changed while for Blowfish the average of Avalanche Effect is about 28.714286. On the other hand the average of Avalanche Effect is about 60.7143 in RC6 Algorithm.

This paper presents a design of a general purpose GA. It is described using the Very high speed integrated circuits Hardware Description Language (VHDL), which is one of the Hardware Description Languages (HDLs). The complete system is implemented in a single Field Programmable Gate Array (FPGA) platform using the Foundation 2.1i, which is a software tool from XILINX. The feasibility of the purposed FPGA-based GA (FPGAGA) is demonstrated by testing it using two case studies. The objective of the first test is to maximize mathematical functions (f(x) = 2x, f(x) = x+5 and f(x) =2x³ -45x² +300x) over the domain0≤x≤15. Simulation results show that the adopted design is able to find the maximum obtainable values for all the functions. The objective of the second test is to solve circuit partitioning problem by distributing given modules (or cells) over two blocks. The number of inter-block connections and the number of modules assigned for each block should be minimum. Simulation results show that the final arrangements reached by the FPGAGA for the given arrangements (consist of 5, 10 and 15 modules) is well optimized in term" of the number of inter-block connections and the modules assigned for each block.

This paper uses the theory of stochastic arithmetic as a solution for the FPGA implementation of a complex feed forward, multi layered neural network. Compared with the traditional digital implementations, the stochastic approach simplifies the computation involved and saves digital resources. The architecture combines stochastic computation techniques with a novel Look Up-Table-based that fully exploits the Look Up-Table structure of many FPGAs. Basic operations of simple ANN are mapped into a modular design. The system control module, random pulse generating module , bit stream generating module , LFSR_32(Liner Feedback Shift Register) sub module, modulator sub module, neuron module and bit stream converter module, are described in hardware using a schematic editor of the Foundation 4.1i, which is a software tool from Xilinx. Thus the modules can be parameterized, providing easy scalability of the system to the different applications constraints and requirements. The feasibility of the proposed ANN is demonstrated by testing it using two case studies. The objective of the first test is the to decomposition of Boolean Function sets (AND, OR, EXOR) the simulation results show that the design is able to find the obtainable values for the functions, while, the objective of the second test is to find the frequency recognition for square wave with different frequencies, the simulation results show that the design is suitable for using in this field.

Block cipher is a major part of cipher algorithm like stream cipher and other techniques. Its power comes from dealing with plaintext as parts and operating on each block independently. Blowfish is a secret-key block cipher proposed by B. Shneier. It is a Feistel network, iterating a simple encryption function 16 times. The block size is 8-bytes and the key can be any length up to 56-bytes. In this paper, a Blowfish was improved to encrypt 16-bytes using a variable key length from 8-bytes up to 144-bytes. During the design of Improved Blowfish algorithm, the pragmatic aim was to satisfy as many goals as possible while keeping the cipher simple. Only by keeping a cipher simple one can achieve a well-understood level of security, good performance, and a versatility of design that makes the cipher highly adaptable to future demands. The improved algorithm reduced the memory requirement by using a single S-box instead of four S-boxes without compromising security. The security of improved Blowfish algorithm will be increased by several techniques where the block size and key length were increased, using more complex function before the first round and after the last round and using a complex function to avoid a symmetric to the output of S-box.

In this paper, a proposed method to implement the image parameter filters is presented. It is based on cascading π-networks and using a proposed bisected-T m-derived matching section to the source and load impedances instead of the use of the cascaded T-networks and the classical bisected-π matching sections. The proposed method achieves the advantage of reducing the total number of the inductors in the circuit which is a great benefit for circuit implementation in the recent monolithic microwave integrated circuit (MMIC) technology. The method also finds application in broadband microwave distributed amplifiers design.

Global Positioning System (GPS) and Strap down Inertial Navigation System (SDINS) can be Integrated Together To Provide A Reliable Navigation System. In This Paper, A Technique For Error Estimation In A GPS/INS System Based On A Low-Cost Inertial Measurement Unit (IMU) Is Offered. This Technique Is Composed Of Wavelet Transform (WT) And Adaptive Fuzzy System (AFS). The Wavelet Decomposition Is Used To De-Noise The Position And Velocity Components Of The GPS And INS Outputs. An AFS Is Introduced In This Paper To Estimate The Position And Velocity Errors In The Integrated System In Order To Provide Accurate Navigation Information About The Moving Vehicle. Several Data Sets Are Processed In This Paper, Where The Simulation Results Are Based On Matlab7 Programming Language. Six AFS Networks Are Used To Process The Position And Velocity Components. The Average Error Value Per Sample Was 0.0142, 0.0443, And 0.0108 M For Position In X, Y, And Z Axes Respectively And 0.0077, 0.0223, And 0.0269 M/S For Velocity In North, East, And Down Directions Respectively

The aim of this work is a proposed system to enhance automatically the contrast of the desired region in the medical image to get the wanted information without enhancing the contrast of the whole image. The proposed system includes the automatic extraction process, the automatic contrast enhancement process and finally reinsertion process for region in the image. Threshold, smoothing, boundary extraction, chain code or region filling techniques were used in the automatic extraction process. While, histogram equalization, histogram stretching, gray level grouping (GLG), fast gray level grouping (FGLG) or auto-contrast techniques were used in the automatic contrast enhancement process for an extraction region from the image. According to image appearance, GLG, FGLG and histogram stretching are the best techniques to enhance contrast in the RGB image. Auto-contrast technique lowers accuracy, while histogram equalization results are unacceptable.