IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING

This paper attempts to tune any controller without the knowledge of mathematical model for the system to be controlled. For that purpose, the optimization algorithm of MATLAB / Nonlinear Control Design Blockset (NCD) is adapted for On-line tuning for controller parameters. To present the methodology, a PID controller is verified with the physical plant using the engine speed control System where the problem of maintaining the engine idle speed at a reference value with the applied load is studied. A Proportional Integral Derivative (PID) Controller is used to solve this problem, but to get the best controller parameters the (NCD) Blockset is used for tuning the PID parameters. Simulation shows promising results in the idle speed response by comparing NCD tuning results with the trial and error results. The analytical results are carried out MATLAB / SIMULINK.

Network Security for data transmission is the most vital issue in modern communication systems. This paper discusses a new steganographic technique and the effectiveness of the proposed method is described through which the idea of enhanced security of data can be achieved. To hide data in a binary image, the proposed method focuses on the Least Significant Bit (LSB) technique in hiding messages in an image. The proposed method enhanced the LSB technique by randomly dispersing the bits of the message in the image and thus making it harder for unauthorized people to extract the original message easily.

This paper discusses the transient voltage stability of a synchronous generator at its bus in a power system with a detailed transient modeling for the generator after being subjected to a three phase fault, and designing a Takagi-Sugeno first order fuzzy logic controller with center of area defuzzification algorithm as a fuzzy logic controller based exciter to stabilize the terminal voltage and to damp its oscillations so as to keep the generator under balanced working conditions. The proposed exciter can be easily modified by changing the steady state field voltage value to be applied to any other synchronous generator. This paper also used the integral of square error as an indicator of the terminal voltage stability and monitored all of the generator variables specially the rotor angle to see whether the generator will maintain synchronism or not after the occurrence of the fault.

Communication network efficiency depends upon many factors among which is the "Topology” which makes topology optimization an important issue to care for. One important thing in optimization problems is the formulation of objective functions. For the case of topology design it is not a straightforward matter to develop an efficient topology model as well as objective functions to be used in the optimization process. An effective unconventional approach is needed. This paper is concerned with enhancing the already existing set of formulas, relating topology and topology properties modeling and topology design objectives, by proposing a 3-dimension way of modeling that can serve network analysis, design, and optimization. The approach is based on graph theory. The proposed model and formulas can be easily programmed.

The Relay is widely used in civil, industrial and military equipment. The Relay is considered to be one of the indispensable actuators for electric power and control flying objects and systems. Relays reliability strongly influences the system reliability. The mathematical model of the servo is introduced including the electrical, magnetic and dynamic parts. Simulations, using Matlab and Simulink, were performed. An improvement to the mathematical model has been carried through simulation which reflected on the results gained. Results of the effect and influence of magnetic materials and some important mechanical parameters like stiffness, viscosity, and copper insulator thickness, on the dynamic performance of the servo were presented. The results can lead to improving the servo performance and get the right design of parameters and right choice of materials.

This paper describes the design and development of a prototype system for the automatic authentication of an individual based on the human ear patterns. Information at the feature extraction and at the confidence level, where the matching scores are reported by Probabilistic neural network, is discussed. The system was tested with the template files. The test performance reaching False Rejection Rate (FRR) = 9% and False Acceptance Rate (FAR) = 9%, suggests that the system can be used in telephone security environments.

Audio biometric person authentication is the task of verifying the identity of a person based on the information in the speech signal that occurs during the production of speech. In this research, audio person authentication is focus on acoustic text-dependent speaker verification system. The proposed recognition process begins by converting that audio into frequency domain by applying discrete cosine transform (DCT), then compute the seven moments as a features for that audio and build a database depends on these features, then compute the Kohonen neural network for person identification, and then compute the dynamic time wrapping (DTW) for verification and patterns matching, and later give the decision logic for accepting or rejecting a claimant.

In this paper, a new Enhanced Genetic Algorithm (EGA) is used to find the best global path planning for a mobile robot according to a specific criterion. The EGA is enhanced by a new encoding method, new initial population creation method, new crossover and mutation operations as well as new additional operations correction operation and classification operation. The study considers the case when the mobile robot works in a known static environment. The new proposed algorithm is built to help the mobile robot to choose the shortest path without it colliding with the obstacles allocated in a working known environment. The use of grid map in the environment helps to locate nodes on the map where all nodes are assigned by coordinate values. The start and the target nodes of the required path are given prior to the proposed algorithm. Each node represents a landmark that the mobile robot either passes through only one time or never passes through during its journey from start node to the target node. Two examples of known static mobile robot environments with many obstacles in each one are studied and the proposed algorithm is applied on them. The results show that the proposed algorithm is very reliable, accurate, efficient and fast to give the best global path planning for the two cases.

In this paper, a controller design is proposed to control systems subjected to uncertainties and perturbed time-varying delay. The proposed controller strategy is composed of three parts, the linear state feedback part is used for assigning the closed loop eigenvalues, and the nonlinear switching part of the sliding mode and the adaptive part are used to achieve the robustness of global stability. By using the stability theorem, the adaptive law is utilized for adapting the unknown bounds of the lumped perturbations so that the objective of asymptotical stability is achieved, and then to use the variable structure control method to enhance the robustness of stability of the controlled systems. Once the system goes inside of the sliding surface of the variable structure controller, the dynamics of the controlled systems are insensitive to effect of perturbations. The system and controller are simulated by using Matlab/Simulink. Finally, a real numerical example is given to demonstrate the feasibility of the proposed controller.

In this work, the power of the Genetic Algorithms (GA) in searching for an optimal solution (in a pre-determined hyper space) is used to design the suitable configuration and parameters of the Proportional-Integral-Derivative (PID) controller. In most industrial plants, the PID controllers are configured either in cascade, feedback or in feed forward topologies. Besides, for each of these configurations the tuning gains have to be fixed in order to meet the required specifications. Therefore, GA is utilized efficiently to select the proper PID configuration in the context of signal following approach as well as the best tuning gains for the selected configuration. The proposed design procedure is applied to linear and nonlinear plants. It reflects a tremendous design results that heavily relied on computer to get the required controller.