Ghazi Al Sukkar

Best relay selection in a multi-relay nodes system under the concept of cognitive radio

In this paper we propose a simple protocol that selects the best relay node in a multi-relay nodes system that works under the cognitive radio technology. The best relay node between the secondary transmitter and the secondary receiver is selected based on the signal-to-noise ratio (SNR). This protocol is examined for many channel conditions. In addition to that, the outage probability performance for this system has been compared with the outage probability of the single-relay system model and the direct path system model. Significant enhancements in the system performance are observed. The numerical results show a noticeable reduction in outage probability when compared to the single-relay system.

Rule-based calculation and simulation design of elevator traffic systems for high-rise office buildings:

Elevator traffic system design has been traditionally based on rules of thumb and the designer’s judgement and expertise. This is especially true for high-rise buildings. This paper attempts to develop a systematic methodology for the design of high-rise buildings, by the use of rational rules. In order to ensure clarity and consistency, it defines the terms sector, zone and stack. A sector is a group of floors that are served by one or more elevators in a journey and are not necessarily fixed and are not necessarily contiguous. A zone is a group of contiguous floors that are served by a group of elevators and are fixed in hardware. When a number of zones are grouped together they form a stack, which is effectively a building within a larger building that is served by a main lobby or by a sky lobby. The systematic methodology is built around the use of rational rules. Rational rules differ from rules of thumbs in a number of ways, and these are discussed in the paper. Six rational rules are presented and used in the design of high-rise buildings. The rules are triggered by the checking of a number of design parameters such as the waiting time and the transit time, as well as the core area used up and the number of elevators in the group. A simulator for incoming traffic and a single entrance is used in order to obtain the parameters for a design and then to trigger the rational rules. Five case studies on the design of various buildings are presented in order to illustrate the use of the six rules. In addition, feedback from the industry experts is reviewed in a dedicated section. Practical application: This paper presents a set of six rules for the design of elevator traffic systems for high-rise buildings. Armed with calculation and simulation tools, the designer can follow the six rules in a systematic procedure in order to arrive at a compliant elevator traffic design for high-rise buildings.

A novel coloring framework for grayscale images

Coloring of grayscale images finds its place in many areas such as medical imaging and coloring of black and white images and videos. However, manual coloring is time consuming and ill-posed problem. In this paper we present a semi-automatic framework for coloring of grayscale images. Given a grayscale image, the new framework operates by prompting the user to specify a source color image of similar content to that of the grayscale image. Then, it employs a large set of grey level features, K-means clustering, and a new color assignment approach to transfer color to the grayscale image. Subjective and objective evaluation revealed the capability of the proposed framework in producing faithful and true color images.

Gray codes for Spatial Modulation systems: An open research issue

Due to the high spectral efficiency of Spatial Modulation (SM) systems, an increasing attention is being paid to investigate SM as a potential candidate for future wireless transmission. Large amount of research has been dedicated for SM performance compared to the current transmission systems. However, the problem of bit to symbol mapping in SM has been rarely investigated in the literature. Unlike other systems, the applied bit to symbol mapping in SM cannot satisfy Gray code principle, which, in turn, degrades the error performance. This article sheds light on this problem as an open research issue. The article starts by exploring the problem, discussing the encountering challenges for potential solutions, and including some expected results, aiming at motivating researchers to handle the problem.

Reconciling the value of the elevator round trip time between calculation and simulation

This paper attempts to understand the reasons for the difference in the value of the round trip time between calculation and simulation. It is posited the main reason for the difference is the combination of two factors: the restricted car capacity and the randomness in the behavior of the elevator traffic system, thus leading to a reduced effective car loading (effectively based on a smaller number of passengers in the car). There are three sources of randomness in the behavior of the system: the randomness of the passenger destinations (thus making the value of the round trip time a random variable), the randomness of the passenger arrival (driven by a Poisson passenger arrival model), and the effect of elevator bunching (thus making the value of the interval a random variable). Using a MATLAB-based simulator, the value of the round trip time is plotted against the system loading level for the case of a single entrance and incoming traffic only. Different conditions are simulated, including constant and random passenger arrivals, as well as queues-allowed and queues-not-allowed conditions. Varying these conditions provides an essential insight into the variation of the round trip time and the reasons for it. The effect of the number of passengers boarding the elevator on the value of the round trip time (and thus on the value of the system handling capacity) is investigated in more detail.

Head movement based control system for quadriplegia patients

A driving aid system, which utilizes only a person head movements, is designed and implemented on a small DC-Motor vehicle prototype. The system is configured to accept a pre-assigned drivers head tilts for the speed and steering control actions. The head tilts are recorded using an accelerometer, which is mounted on a head-band that fits the driver head. The head tilts collected data are transmitted via a Bluetooth transmitter after being interpreted using a Fuzzy Logic based interpreter. Once the data is received by the vehicles on-board Bluetooth module, it passes to the steering and speed servo-controllers. Both Fuzzy Logic controller and a conventional PID controller are used to carry out the transmitted commands. The driving aid system is first implemented on microcontroller Platform and is verified for proper operation using software. Furthermore, the complete integrated system is tested for functionality and performance.

Best path selection in a multi-relay node system under the concept of cognitive radio

The main purpose in this work is to enhance relay technique in underlay cognitive radio scheme through estimating the best path between the secondary source and the secondary destination under the power interference constraint of the primary user. A protocol is proposed based on the cooperation process between the secondary relay nodes in the system in order to establish the best path at low complexity without exceeding the interference threshold of the primary user. Performance analyses, through simulation, of the suggested protocol shows great enhancement in network outage probability when compared with direct path model and one relay node based-model.