Mohammed T. Simsim

A novel impedance multiplier using low voltage digitally controlled CCII

The digitally controlled current conveyor has been used to realize a novel digitally controlled impedance multiplier. The realized impedance multiplier can provide positive or negative multiplying factor with directly or inversely proportional to an n-bit digital control word. The digitally controlled multiplier is utilized for the realization of a first order continuous time filter with low pass and high pass responses. The pole frequency of the filters is programmable through digital control word. The realized digitally controlled continuous time filter is designed and verified using PSPICE and the results thus obtained justify the theory.

Safety Measurements of Electromagnetic Fields Radiated from Mobile Base Stations in the Western Region of Saudi Arabia

Over the last decade, detrimental effects of human exposure to electromagnetic radiations have received widespread attention. Communications and Information Technology Commission (CITC) in Saudi Arabia has set guidelines and launched a national project—in collaboration with academic and research institutions—to perform measurements of the “electromagnetic fields” (EMFs) radiated from base stations of the mobile phone network. In keeping with its mission to address problems of the local community, Electrical Engineering (EE) department at Umm Al-Qura University (UQU) has been commissioned to conduct this project in the western region of Saudi Arabia. The project is concerned with measuring the strength of EMFs around base stations to locate the Maximum Peak Point (MPP). The aim of measurements is to ensure the site compliance with the CITC guidelines for human exposure to Radiofrequency (RF). This paper discusses possible health consequences caused by human exposure to RF radiations. Furthermore, it sum- marizes the results from 20 selective base stations located in Makkah, Madinah, Jeddah, Taif and Yanbu. The results show that EMF levels at all surveyed sites are far below the National Guidelines for public exposure to RF and that the MPPs are found within the distance range suggested in the CITC guidelines. The paper concludes by providing some useful comments and recommendations for RF sites surveyors.

Reconfigurable continuous time current mode first order multifunctional filter using low voltage digitally controlled CMOS CCII

The digitally controlled current conveyor has been used to realize a novel digitally controlled reconfigurable continuous time current mode first order multifunctional filter. The realized filter can provide first order current mode low pass, high pass and all pass responses without any component matching constraints. The pole frequency of the continuous time filter is directly proportional to an n-bit digital control word. The realized digitally controlled continuous time filter is designed and verified using PSPICE and the results thus obtained justify the theory.

Spiral path simulation of pedestrian flow during Tawaf

Pedestrian agent performing Tawaf is modelled using the concept of parameterization of spiral. The agents are set at defined velocities on spiral trajectory, moving counter clockwise mode inward and outward for decreasing and increasing radii. We present a new trajectory path planning that simulates the movement of individual agents performing Tawaf. Our aim is to simulate complex scenarios involving multiple agents interacting with each other and avoiding collision within a defined path. The simulation was carried out for two proposed approaches; Spiral movement of agents for seven lapses in order of four inward and three outward (4in_3out) and undirected movement in circular pattern. An agent flow optimization comparison was carried out between the proposed methods for agents flow rate, average velocity, Tawaf duration and maximum densities of pedestrians. We found that the spiral movement 4in_3out presents better Tawaf ritual performance with durations of 38 minutes and average density of 4.2 agents per square meter.

ID-based secure real-time tracking system

This article focuses on the security issues involved in the transportation of valuable materials. It tries to build a secure smart real-time freight tracking system in which the valuable materials can be under inspection and control at all times during its transportation from the supplier to the end user. The real-time tracking system can be achieved by combining technologies from Real-Time Tracking Systems (RTTSs), such as GPS and RFID, while the system environment sensing can be achieved using Wireless Sensor Network (WSN) that can add sensing ability to the moving valuable materials. This paper not only proposes a novel Identity-Based Cryptosystem (IBC) for securing an E-Seal that can be used to secure the communication of the real-time tracking communication but also addresses IBC based with lightweight computation specification that can be used in low computation devices for locking and unlocking of the E-Seal.

Collision Avoidance Path for Pedestrian Agent Performing Tawaf

Collision is one of the major problems affecting the flow of pedestrian in a dense environment. The case study of this research work is the ground flow of Tawaf area (Mataf) at Masjid Al-Haram, Saudi Arabia. We propose a spiral model, that simulates the movement of 1,000 agents toward a unify direction while ensuring minimal collision among pedestrians during Tawaf. Based on our findings the spiral path movement is recommended for Tawaf movement. Several simulation trials were run. Outcomes such as average speed, duration and density were computed for different combination of spiral turn.

Compressed VFH descriptor for 3D object classification

This paper presented a compressed version of viewpoint feature histogram descriptor (VFH) for object classification based on shape recognition. VFH is known for representing geometrical features (3D rotation angles) of 3D points with concatenated histogram. However this histogram is large and sparse. The proposed descriptor employ eigenvalue decomposition to extract dominant orientation features from the point cloud and using it as a descriptor instead of sparse histogram. Using dominant features maintains the main properties of the object with minimal descriptor length which applicable for recognizing the geometrical class of 3D objects (sphere, rectangle, ... etc). This descriptor was tested for two class and multi-class 3D object classification using support vector machines (SVM). The new descriptor showed promising matching results of 88% for two class classification and 83% for multiple class classification of 3D objects.

Design and Optimization of a Permanent Magnet Rotating Machine for Power Cooling Generation

Magnetic refrigeration is an innovative, revolutionary, e-cient and environmentally friendly cooling technology which is on the threshold of commercialization. The essential components of magnetic refrigeration system are the magnetic fleld generator and the magnetocaloric material. The two main goals of this paper are to design and to optimize a permanent magnet magnetic refrigeration machine for power cooling generation, where an initial conflguration is studied and based on this study two other conflgurations are presented. Both electromagnetic and thermal studies are explored. The electromagnetic design part has been accomplished by using the flnite elements method and the thermal design part has been achieved using the flnite difierence method.

EMSoft- software for graduate and undergraduate educational Electromagnetics

The study of Electromagnetics is required in most electrical engineering graduate and undergraduate curricula. Traditional methods for teaching Electromagnetics are abstract, theoretical and filled with infinite number of mathematical equations. Thus, they are not anymore appropriate. The solution is to provide to both professors and students an interactive software with a simplified graphic interface to best teach and learn fundamentals of Electromagnetism. Interactive resources have demonstrated that they were attractive and encouraged the students to be active and autonomous. The aim of this work is to present such software called EMSoft. It uses the calculation functions of Matlab, combined with the powerful graphical user interfaces of Java.

Design of a linear magnetic refrigeration structure running with rotating bar-shaped magnets

Magnetic refrigeration (MR) is a cooling technology based on the magnetocaloric effect (MCE). It has the potential to replace conventional refrigeration systems. Recent development in magnetic refrigeration technology has encouraged researchers all over the world to think about some new original systems. This paper aims to describe a new magnetic refrigeration structure based on a rotating bar shaped configuration.