Hesham Altwaijry

Bayesian Based Intrusion Detection System

In this paper intrusion detection using Bayesian probability is discussed. The systems designed are trained a priori using a subset of the KDD dataset. The trained classifier is then tested using a larger subset of KDD dataset. Initially, a system was developed using a naive Bayesian classifier that is used to identify possible intrusions. This classifier was able to detect intrusion with an acceptable detection rate. The classier was then extended to a multi-layer Bayesian based intrusion detection. Finally, we introduce the concept that the best possible intrusion detection system is a layered approach using different techniques in each layer.

Effects of VANET's attributes on network performance

A simple flooding mechanism for broadcasting messages over vehicular ad-hoc networks causes massive message redundancy, contention and collision known as the broadcast storm problem. Most available solutions to broadcast storm are normally based on the selection of the rebroadcast nodes depending on a given single attribute such as: sender-to-receiver distance, node density, vehicles speed, movement direction, or number of message duplicates received. As the settings of any given attributes may remarkably impact the network performance, comparisons of such settings are therefore, an important research topic. In this paper, we suggest a simple but effective solution to the VANET broadcast storm problem through comparison of various attribute settings and select the rebroadcasting nodes based on a combination of multi- network and node attributes. To the best of our knowledge, most of the solutions to the broadcast-storm problem make use of only single-attribute schemes and do not consider on employing two or more attributes for broadcast suppression. The scheme suggested throughout this paper is valuable for two reasons: First, it is considered as a guide to select proper methods/attributes for a specific network applications goal, e.g. maximum reachability with a reduced redundancy and/or with minimum message delay at specific network densities. Second, it sets a basis for future studies that employ multiple attributes on mitigating broadcast-storm through machine-learning-based approach. The simulation results of this proposed scheme show that a proper combination of attributes may outperform the performance of the best single-attribute-based schemes. A combined broadcast scheme which implements both distance and duplicate attributes provides a remarkable reduction on message redundancy by 41% compared to the best single distance-based attribute broadcast.

An implementation of a 2D FIR filter using the signed-digit number system

An FIR filter is implemented in this work. Enhancing the arithmetic operations of the filter is considered. For the addition operation, the signed-digit number system is utilized. For the multiplication operation, Booth-3 algorithm is used to reduce the number of partial products. Then a 1D filter is used to construct a 2D filter that is deployed on real hardware in an image processing application.

An algorithmic approach to building datapath multipliers using (3,2) counters

Traditionally multipliers have been laid out manually, using simple delay models for the counters. However, at deep submicron feature sizes, these delay models do not accurately model the resulting delays. Therefore, an algorithmic approach to the design of the multiplier is required. This paper presents an algorithm that connects the counters of the multiplier, under the constraint of a limited number of available wiring tracks. The algorithm uses an advanced delay model for the (3-2) counter. This delay model includes the incremental delay due to the placement and wiring of the counters. The algorithm has been implemented and the resulting program has been used to compare several designs of an IEEE floating point multiplier using several delay models.

FIR Filter Design Using The Signed-Digit Number System and Carry Save Adders - A Comparison

This work looks at optimizing finite impulse response (FIR) filters from an arithmetic perspective. Since the main two arithmetic operations in the convolution equations are addition and multiplication, they are the targets of the optimization. Therefore, considering carry-propagate-free addition techniques should enhance the addition operation of the filter. The signed-digit number system is utilized to speedup addition in the filter. An alternative carry propagate free fast adder, carry-save adder, is also used here to compare its performance to the signed-digit adder. For multiplication, Booth encoding is used to reduce the number of partial products. The two filters are modeled in VHDL, synthesized and place-and- routed. The filters are deployed on a development board to filter digital images. The resultant hardware is analyzed for speed and logic utilization

Linear probability based admission control policy for video on demand system

In this paper, we propose a dynamic admission control policy for distributed video on demand system, based on linear probability function. The probability of accepting a video request is calculated by using a liner mathematical formula. Quality of service (QoS) is granted by restricting the requests on the basis of popularity of request and availability of resources. The popular video request will get better chance to be accepted. The distinction of this paper from the others is dynamic admission control policy instead of static and threshold. The evaluation of proposed system is done by simulation model, number of rejected requests and total generated revenue is calculated for performance measurement, and it is observed that proposed admission control policy not only improves the performance of all the request classes but also improves a lot the overall system.