https://repository.sustech.edu/handle/123456789/16639 Sat, 04 Apr 2026 13:06:06 GMT 2026-04-04T13:06:06Z https://repository.sustech.edu/handle/123456789/16641 Title: Speed Sensorless Vector Control of Induction Motors Using Rotor Flux based Model Reference Adaptive System Authors: Ahmed , Aamir Hashim Obeid Abstract: Vector Control (VC) schemes are increasingly used in Induction Motor (IM) drive systems to obtain high performance. However, in order to implement the vector control technique, the induction motor speed information is required. Different speed sensors are used to detect the speed. But in most applications, speed sensors have several problems. These problems are eliminated by speed estimation by using different speed estimation algorithms. Out of which, Model Reference Adaptive System (MRAS) techniques are one of the popular methods to estimate the rotor speed due to its good performance and simplicity. In this paper, the induction motor with Rotor Flux based Model Reference Adaptive System (RF-MRAS) rotor speed estimator is designed and validated through MATLAB/SIMULINK software package. The results of simulations show that the performance of the speed estimation is very good under different operation conditions. Description: article Fri, 01 Jan 2016 00:00:00 GMT https://repository.sustech.edu/handle/123456789/16641 2016-01-01T00:00:00Z https://repository.sustech.edu/handle/123456789/16642 Title: Time Series Analysis of Nyala Rainfall Using ARIMA Method Authors: Mohamed , Tariq Mahgoub; ibrahim , abbas abdalla Abstract: This paper presents linear stochastic models known as multiplicative seasonal autoregressive integrated moving average model (SARIMA).The model is used to simulate monthly rainfall in Nyala station, Sudan. For the analysis, monthly rainfall data for the years 1971–2010 were used. The seasonality observed in Auto Correlation Function (ACF) and Partial Auto Correlation Function (PACF) plots of monthly rainfall data was removed using first order seasonal differencing prior to the development of the SARIMA model. Interestingly, the SARIMA (0,0,0)x(0,1,1)12 model developed was found to be most suitable for simulating monthly rainfall over Nyala station. This model is considered appropriate to forecast the monthly rainfall to assist decision makers to establish priorities for water demand, storage, distribution and disaster management. Description: article Fri, 01 Jan 2016 00:00:00 GMT https://repository.sustech.edu/handle/123456789/16642 2016-01-01T00:00:00Z https://repository.sustech.edu/handle/123456789/16643 Title: Speed Estimation for Indirect Field Oriented Control of Induction Motor Using Extended Kalman Filter Authors: Ahmed , Aamir Hashim Obeid Abstract: ABSTRACT - Speed sensors are required for the Field Oriented Control (FOC) of induction motors. These sensors reduce the sturdiness of the system and make it expensive. Therefore, a drive system without speed sensors is required. This paper presents a detailed study of the Extended Kalman Filter (EKF) for estimating the rotor speed of an Induction Motor (IM). Using MATLAB/SIMULINK software, a simulation model is built and tested. The simulation results illustrated and demonstrated the good performance and robustness of the EKF to estimate the high and low speed. Moreover, the performance of the EKF is found to be satisfactory in case there are external disturbances. Description: article Fri, 01 Jan 2016 00:00:00 GMT https://repository.sustech.edu/handle/123456789/16643 2016-01-01T00:00:00Z https://repository.sustech.edu/handle/123456789/16646 Title: DES Security Enhancement using Genetic Algorithm Authors: Mohammed , Ayman E.; Abdalla , Faisal M. Abstract: In this paper is proposed method for creating Data Encryption Standard (DES) sub-keys. The proposal simplifies the creation and expansion process of the encryption key of the Data Encryption Standard (DES) algorithm, which is considered one of the most important elements in the process of encryption. The sub-keys generation methods is implemented by using a genetic algorithm. The sub-keys generated using this method, based on genetic algorithm; they give a totally different group of pseudorandom sub-keys each time program is executed.Furthermore, comparison analyses between the proposed method sub-keys generation process and the standard technique used in Data Encryption Standard (DES) it give optimum results.The proposed method is also evaluated and subjected to many randomness tests in order to measure it‟s strength after encryption using National Institute of Standards and Technology-Test Suite is a statistical (NIST-STS) for randomness tests. The result shows that the proposed method gives good result and can be used it in many ciphers for sub-keys generation. Description: article Fri, 01 Jan 2016 00:00:00 GMT https://repository.sustech.edu/handle/123456789/16646 2016-01-01T00:00:00Z