Ahmed Hamad

Relative RSS-based GSM localization technique

Context-aware applications have been gaining huge interest in the last few years. With cell phones becoming ubiquitous computing devices, cell phone localization has become an important research problem, and numerous localization solutions have been proposed. Database Correlation Method (DCM) is a positioning technology that based on a premeasured database of a location dependent variable such as Received Signal Strength (RSS) or Link Quality Identifier. DCM has shown superior in terms of accuracy. Absolute RSS values received from base station change with time, but the relative RSS values which refer to the relations of the RSS values between different base stations are more stable. This study has proposed and implemented a robust technique for both positioning and traffic estimation using Relative Received Signal Strength (RRSS) of GSM. The study has been tested and analysed in Egypt roads using realistic data and Android smart phones. The performance evaluation showed good results. Mean positioning accuracy was about 29 m in urban areas and velocity estimation was about 1 km/h in rural areas.

Web 2.0 Based Service-Oriented E-Learning Systems: Recurrent Design and Architectural Patterns

Adopting Web 2.0 technologies and techniques in modern e-learning systems guarantees a more interactive e-learning experience. It leverages collaboration among learners and enhances accessibility to various learning resources. Providing such functionalities as web services within an integrated e-learning system achieves interoperability and reduces redundancy. Our aim in this paper is to identify recurrent Web 2.0 and Service-oriented architecture (SOA) design and architectural patterns that would provide reusable building blocks for any Web 2.0 based service-oriented e-learning system. The paper builds on induction theory techniques to validate taxonomy related to Web 2.0 and SOA behavioural and technological patterns. We identified 3 elementary design patterns, inter-connectivity, file sharing and content re-mixing, a well as 4 secondary design patterns, streaming, content authoring, content aggregation and tagging. The proposed design patterns share three elementary architecture types, client-server, peer-peer and SOA. The paper also builds on UML4SOA techniques in modelling requirements prior application of proposed patterns in the case study.

GSM-Based Positioning Technique Using Relative Received Signal Strength

Context-aware applications have been gaining huge interest in the last few years. With cell phones becoming ubiquitous computing devices, cell phone localization has become an important research problem. Database Correlation Method DCM is a positioning technology that based on a database of a premeasured location dependent variable such as Received Signal Strength RSS. DCM has shown superior in terms of accuracy. Absolute RSS values received from a base station change with time, but the relative RSS RRSS values which refer to the relations of the RSS values between different base stations are more stable. This study proposes and implements a robust RRSS GSM-based technique for both positioning and traffic estimation. The study was tested and analyzed in Egypt roads using realistic data and Android smart phones. The performance evaluation showed good results. Mean positioning accuracy was about 29m in urban areas and velocity estimation was about 1 km/h in rural areas.

Towards Usage-Centered Design Patterns for Social Networking Systems

The role of social networks is becoming increasingly relevant in the recent years. While social networks are becoming more ubiquitous, a profound approach guiding the analysis, design and development of such social systems is becoming increasingly important. This research focuses on deriving functionalities that classify behavior of social networking applications. This led to identifying three basic/elementary usage patterns which include; interconnectivity, file sharing and tagging, while the intersection between these patterns led to other secondary/supportive usage patterns which include content authoring, content remixing, content aggregation & syndication and content streaming. By interlinking the proposed patterns of usage with underlying techniques and Web 2.0 tools we aim to provide insight into re-usable elementary building blocks common to any type of social networks. As a result a usage-centered roadmap is presented that identifies the intersection of several Web 2.0 tools and techniques used to realize the three identified social networking patterns of usage.

Evaluation of Probabilistic Payment Systems

With the development of pay-per-view and multimedia streaming services, there is an increasing demand for practical micropayment mechanisms. In this paper, we investigate the applicability of probabilistic payment schemes for micropayments and propose a framework to evaluate them. The framework consists of a well structured parameter vector of characteristics such as transaction cost, delay, computation overhead, overcharging and anonymity. It is applied to lottery tickets, coin flipping and MR2 schemes. Results show that lottery tickets and MR2 have nearly the same transaction computation overhead, delay, anonymity, loss risk and non-refutability. MR2 scheme has lower traffic cost, it provides message integrity, authentication, no overcharging, while lottery tickets scheme prevents double spending. MR2 scheme is best suited for micropayments but it still needs a lot of work in respect of building a working micropayment system

Fuzzy based Tuning Congestion Window for Improving End-to-End Congestion Control Protocols

Transmission Control Protocol (TCP) is the transport-layer protocol widely used in the internet today. TCP performance is strongly influenced by its congestion control algorithms which limit the amount of transmitted traffic based on the estimated network capacity to avoid sending packets that may be dropped later. In other words Congestion Control is Algorithms that prevent the sender from overloading the network. This paper presents a modified fuzzy controller implementation to estimate the network capacity which reflected by congestion window size. Fuzzy controller use Round Trip Time “RTT” as network traffic indication as well as current window size and slow start threshold “ssthresh” as currently occupied bandwidth indicator. NS2 used as a simulation tool to compare proposed fuzzy approach with most widespread congestion control protocols including; TCP-Tahoe, Reno, New Reno, and Sack. Simulation results show that the proposed mechanism improves the performance against throughput, packet drop, packet delay, and connection fairness. General Terms: Computer Networks, Network Protocols.

Enhancing VANET connectivity through utilizing autonomous vehicles

Connectivity in vehicular networks is continuously changing due to high mobility of vehicles, causing rapid changes in the network topology. This has a direct negative impact on the throughput and packet transmission delay. Many algorithms and approaches have been proposed to address this problem. However, most of them are not practical due to their dependence on a centralized infrastructure, which are attributed with high cost for installation and maintenance. Vehicular networks are composed of all types of vehicles including autonomous and non-autonomous vehicles. In this paper, we propose addressing the problem of VANET connectivity through controlling the routes and speed of autonomous vehicles according to the density and speed of non-autonomous vehicles. This is achieved through a decentralized cooperative game theory approach that provides a balance between autonomous vehicles trip duration, and enhancements to the VANET connectivity. We evaluate our proposed approach through extensive simulations using real traffic data, and observe substantial enhancements of up to 46% in the network connectivity using our approach.

Performance comparison for feature selection in Musical Information Retrieval

Music Information Retrieval (MIR) is an interesting area of investigation. The MIR research aims to develop new techniques for processing musical information and searching music databases by content. Therefore, robust retrieval and matching techniques are required. This paper devises a more practical and efficient approach to MIR by investigating a variety of statistical and signal processing-based features, such as Fast Fourier Transform (FFT), Linear Predicative Coding coefficients LPC, Pitch and the wavelet analysis. The features were tested by using different measures of melodic similarity to achieve a better search in musical databases. The paper uses the recall measure to evaluate the retrieval results. It indicated a poor retrieval quality with statistical features and LPC parameters and it is improved when we used the FFT coefficients, and finally using wavelet coefficients caused a significant improvement in its value.

Predictive direction location update scheme for next generation PCS networks

We consider the problem of locating mobile users in wireless networks with the focus on minimizing the overall cost incurred by the two main activities involved, mainly lookup and update. We propose a location update protocol that relies on the deployment of prediction techniques along with the Direction Based Update algorithm. The proposed protocol is implemented over both random walk and random waypoint mobility patterns. The results obtained proved a reduction in the overall cost up to 47% compared to the direction based location update scheme with line paging for random waypoint mobility pattern.

An approach to improve airborne radar performance in clutter environment

This paper introduces a technique for clutter reduction in airborne radar systems. This technique is based on the fact that the nature of the clutter and target are different in the sense that the clutter returns are randomly distributed from scan to scan, while those for target have a deterministic behavior. An algorithm is developed to discriminate between target and clutter returns from one scan frame to another, where 3 out of 5 criteria used to correlate successive scan frames were adopted. A series of simulation experiments are carried out where the algorithm is applied on range-scan frames. The results show a reduction in P/sub fa/ with an increase in P/sub D/ for different target scenarios.