Abeer Mahmoud

A Hybrid Genetic Algorithm — Decision Tree Classifier

Studies of data mining classification algorithms have shown that these algorithms either cause a loss of quality or scalability aspects or cannot effectively uncover the data structure. This paper presents a new approach for developing two C4.5 based classifiers. The first, RFC4.5, uses the RainForest framework approach while the second, GARFC4.5, uses genetic algorithm. The two classifiers have been applied on medical database of 20MB size for thrombosis diseases, obtained from the discovery challenge competition of the 3rd European Conference on Principles and Practice of Knowledge Discovery in Database held in Prague, 1999. The results show that the two Classifiers give higher classification accuracy than traditional C4.5 classifier. For both classifiers, at a certain population size, it is found that the classification accuracy increases with sample size.

Circular trajectory simulation analysis of a rotating four-legged robot

This paper presents a C++ object oriented based simulator for a rotating four-legged mobile robot called PEOPLER. This simulator facilitates the analysis of the robot circular trajectory influenced by ground friction coefficient and payload operating on landing contacts. The results show reasonable robot motion behavior depending on different walking strides.

Development of an Expert System for Diabetic Type-2 Diet

A successful intelligent control of patient food for treatment purpose must combines patient interesting food list and doctors efficient treatment food list. Actually, many rural communities in Sudan have extremely limited access to diabetic diet centers. People travel long distances to clinics or medical facilities, and there is a shortage of medical experts in most of these facilities. This results in slow service, and patients end up waiting long hours without receiving any attention. Hence diabetic diet expert systems can play a significant role in such cases where medical experts are not readily available. This paper presents the design and implementation of an intelligent medical expert system for diabetes diet that intended to be used in Sudan. The development of the proposed expert system went through a number of stages such problem and need identification, requirements analysis, knowledge acquisition, formalization, design and implementation. Visual prolog was used for designing the graphical user interface and the implementation of the system. The proposed expert system is a promising helpful tool that reduces the workload for physicians and provides diabetics with simple and valuable assistance.

Trajectory estimation of a skid-steering mobile robot propelled by independently driven wheels

This paper analyses a mobile robot with independently rotating wheels travelling on uneven but smooth ground, including ascending or descending surfaces. We formulate a mathematical expression for the energy cost of the robots movement. For our analysis, we utilise the principle of virtual work and assume that the robot moves with a fixed arrangement of wheel axes and without using a steering handle. The mathematical model reveals that the coefficient of friction and the payload distribution dominate the wheel behaviour, including slipping and skidding. We minimise the virtual work expression to determine the robots motion complying with driven wheels. The model also enables us to estimate trajectories for different ground conditions. A hybrid robot, PEOPLER-II, is used to demonstrate the predicted motions, including turns and spins, by following angular velocity control rules. Experimental data verifies that the proposed formulation and minimisation of virtual work are valid techniques for predicting a robots trajectory. The method described is widely applicable to wheeled robots having independently driven wheels.

Software and Hardware control of a hybrid robot for switching between leg-type and wheel-type modes

One of the objectives of the paper is to describe the hybrid robot PEOPLER-II (Perpendicularly Oriented Planetary Legged Robot) with regard to switching between leg-type and wheel-type. Our robot has an easier design and control system than other hybrid robots. The software and hardware control in the process of performing five robot tasks are considered. These are the walking, rolling, switching, turning and spinning. In the switching task, we show the control method based on minimization of total energycost. Also, the hardware components and their interconnections are described. The graphical user interfaces utilized in the simulation and experiment are demonstrated. The walking, rolling and the switching without reverse rotation and arm motion are verified in simulation and with real robot, in addition to turning and spinning.

Trajectory estimation of a skid-steering mobile robot incorporating free wheels

This paper proposes a trajectory estimation method for a skid-steering mobile robot (SSMR) incorporating free wheels on uneven but smooth ground with different ground properties and distributed loads on wheel axes. We formulate a mathematical expression in terms of virtual work for evaluating the energy cost of all the wheel motions with skidding and slipping under the condition that each wheel is always in contact with the ground via a pivot suspension structure. Minimization of the expression for virtual work results in a unique solution for the new position of the robot after small movement of the wheels. Further, by iterating we calculate a continuous trajectory which is an important result for assigning powered wheel velocities for self-navigation. Trajectories demonstrated by a test robot confirm the validity of the method.

Estimation and verification of the trajectory forms generated by a legged sliding robot

This paper presents an 3D algorithm to estimate the motion trajectory of a four legged sliding robot considering the ground friction coefficient and the payload distribution at leg ends during walk on a flat ground including ascending or descending slopes. We formulate mathematical expression for estimating energy cost of motion utilizing the principle of virtual work under the condition where the robot moves by alternating pivotal feet having hemispherical form at their ends. Then we minimize the sum of the virtual work for determining actual robot motion. Results of the minimization make it possible to simulate the motion behaviors for visualizing robot trajectory in different traveling environments. Additionally, we verify simulation results by demonstrating the walk with functions of turn and spin as a legged type of the hybrid robot PEOPLER-II. Hence the proposed algorithm is useful for clarifying the robot motion behaviors.