Ahmad El Hajj

Ahmad El Hajj
Beirut Arab University | BAU · Department of Electrical and Computer Engineering

PhD

About

41
Publications
13,164
Reads
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435
Citations
Citations since 2016
19 Research Items
306 Citations
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2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080

Publications

Publications (41)
Article
Full-text available
Fooling neural networks is a main concern in the process of Artificial Intelligence optimization. Character perturbation make part of a text unnoticeable for some systems, even for human observers. This research focuses the probe on a novel input preprocessing technique, which applies with the Convolutional Neural Networks for character recognition...
Conference Paper
Full-text available
The limitations in binary data transmission are mainly for low speed and a notable increase in energy consumption. Whereas, Multiple-Valued Logic (MVL) has over two-valued logic to increase the speed and to reduce energy consumption. Therefore, this paper proposes a Ternary-to-Binary Converter based on Carbon Nano-Tube Field Effect Transistors (CNF...
Conference Paper
Full-text available
In a world where many overlapping 2G, 3G, and 4G electromagnetic radiation sources already exist, concerns regarding the potential increase in these radiation levels following the roll-out of 5G networks are growing. The deployment of 5G is expected to increase power density levels drastically, given the limitations of mmWave communications that im...
Preprint
The present decade has witnessed proliferate of embedded systems that depend on batteries consumption. In addition, multiple-valued logic (MVL) circuits present significant advances in interconnection complexity and energy consumption over binary circuits. Thus, this letter proposes 32 nm channel CNFET-based ternary multiplier (TMUL) using the prop...
Preprint
Full-text available
Multiple-Valued Logic (MVL) systems present important improvements in terms of interconnection complexity and energy consumption over binary systems. Therefore, this paper proposes the ternary arithmetic logic unit (TALU) circuits that reduce energy consumption in the context of low-power embedded circuits to preserve their battery consumption. The...
Article
Multi-valued logic (MVL) has more than two-valued logic to decrease the interconnections and energy consumption. Also, the market has seen a significant increase in portable electronics and embedded systems, which depend on batteries. Therefore, this paper proposes 32 nm channel CNFET-Based a Ternary Half Adder (THA) and a “decoder-less” Ternary Mu...
Article
Mobile monitoring of electroencephalogram (EEG) signals is prone to different sources of artifacts. Most importantly, motion-related artifacts present a major challenge hindering the clean acquisition of EEG data as they spread all over the scalp and across all frequency bands. This leads to additional complexity in the development of neurologicall...
Conference Paper
Full-text available
The ternary circuit has an advantage over the binary circuit concerning interconnect complexity, propagation delay, and energy consumption. This paper proposes a novel binary-to-ternary converter using Double Pass-Transistor (DPL) with four bits as input and three trits as output. The importance of this work is gained through its potential to incre...
Article
Full-text available
The growing demand for data along with the emergence of new communication standards have reshaped wireless networks through a denser base station deployment, an increasing traffic heterogeneity, and an additional complexity in quality of service (QoS) assurance. Orthogonal Frequency Division Multiple Access (OFDMA) is considered as one technique to...
Article
Full-text available
Recently, the demand for portable electronics and embedded systems has increased. These devices need low-power circuit designs because they depend on batteries as an energy resource. Moreover, Multi-Valued Logic (MVL) circuits provide notable improvements over binary circuits in terms of interconnect complexity, chip area, propagation delay, and en...
Conference Paper
The development of a neurologically-oriented mobile health system involves significant challenges in terms of the proper sensing and efficient transmission of electroencephalogram (EEG) signals, and the faithful reconstruction of these signals at the receiving node. EEG compression has been widely used to reduce storage requirements, improve the re...
Conference Paper
This work proposes a novel patient-aware approach that utilizes an n-gram based pattern recognition algorithm to analyze scalp electroencephalogram (EEG) data and predict epileptic seizures. The method addresses the major challenge of extracting distinctive features from EEG signals through a detection of spatio-temporal signatures related to neuro...
Article
With the advent of mobile services with asymmetric and symmetric quality of service (QoS) requirements, traditional single link resource allocation techniques have started to show some limitations in handling the complex requirements. To address these issues, joint uplink/downlink resource management approaches were recently introduced where both c...
Article
Energy is becoming a main concern nowadays due to the increasing demands on natural energy resources. Base stations (BSs) consume up to 80% of the total energy expenditure in a cellular network. In this paper, we propose and evaluate a green radio network planning approach by jointly optimizing the number of active BSs and the BS on/off switching p...
Article
With the large increase in data services with asymmetric traffic loads, the time division duplexing (TDD) mode of operation of the next generation cellular wireless standards has gained an increasing interest from both cellular network operators and the research community. However, the introduction of TDD has raised several critical design requirem...
Conference Paper
Quality of Experience (QoE) is a very important metric in wireless communication systems, where customers request strict QoE demands that translate into restrictions on both Uplink (UL) and Downlink (DL) connections. The development of wireless communications standards and the emergence of new interactive and conversational services with bi-directi...
Conference Paper
The advancement of wireless communications standards and the introduction of new services with tight bidirectional quality of service requirements necessitated the development of novel and intelligent resource allocation algorithms. These include delay-aware scheduling techniques to cope with the tight round trip delay constraints imposed by the st...
Conference Paper
Quality of Service (QoS) is a very important metric in wireless communication systems, where both Uplink (UL) and Downlink (DL) connections request strict QoS demands in terms of rate, delay, etc. for their proper operation. The development of wireless communications standards and the emergence of new interactive and conversational services with bi...
Conference Paper
The emergence of resource-demanding wireless services such as mobile gaming or multimedia applications motivates the introduction of advanced paradigms for resource allocation in next-generation OFDMA-based wireless networks. In this context, while existing literature mainly focused on schemes in which the uplink and downlink resources are consider...
Article
The emergence of state-of-the-art OFDMA-based wireless standards paved the way to new services with bi-directional requirements. In this paper, we present a probabilistic channel-aware, queue-aware and service-aware joint uplink/ downlink resource allocation scheme. The approach consists of coupling the queue behavior probabilistically by minimizin...
Conference Paper
The recent trend towards energy-efficient and environment-aware network operations has mandated the development of novel green network planning paradigms. In this context, while existing work focused on developing reactive energy reduction techniques after complete network deployment, this paper presents a proactive green radio network planning (RN...
Article
Resource allocation in the uplink of orthogonal frequency-division multiple access systems is investigated. The problem of ergodic utility maximisation with discrete rates is formulated and solved using dual Lagrangian techniques. Suboptimal algorithms based on equal power allocation over the subcarriers are proposed. Results are presented and comp...
Conference Paper
The development of the Time Division Duplexing (TDD) mode in next generation OFDMA-based wireless standards has brought some major advantages but at the same time raised several critical design requirements. Among others, the introduced flexibility in splitting resources between the uplink and downlink directions makes of the uplink/downlink switch...
Conference Paper
The emergence of new wireless technologies paved the way to the introduction of a new class of symmetric services with joint uplink/downlink quality of service requirements. In this paper, we formulate joint uplink/downlink resource allocation in OFDMA networks as an optimization problem with total sum- rate maximization as an objective function. A...
Article
The weighted ergodic sum-rate maximisation problem subject to per-user power and rate constraints in the orthogonal frequency division multiple access uplink is formulated and solved. The solution is found via dual optimisation techniques, and the duality gap between the primal and dual solutions is analysed. Ergodicity allows taking advantage of t...
Conference Paper
Full-text available
We present SinPack, a security protocol for preventing packet pollution attacks in network-coded content distribution networks. SinPack employs a homomorphically-addressable Bloom filter data structure to enforce the integrity of network-coded packets all the way from source to destination. Using a Bloom filter "amortizes" the functionality of trad...
Conference Paper
In this paper, we propose and evaluate a new interference co-ordination scheme for the uplink of LTE systems. This presented approach mitigates the effects of ICI (Inter-Cell Interference) by finding suboptimal frequency and power assignments to all users in a given cellular network. The spectral efficiency of cell-edge users is enhanced in this sc...
Conference Paper
Weighted ergodic sum-rate maximization in OFDMA uplink is investigated. A finite set of achievable rates is assumed. The problem is formulated as a convex optimization problem. An analytical solution is derived using the Lagrangian dual decomposition. Numerical results show that the weights can be adjusted to increase the fairness in the system or...
Conference Paper
Full-text available
Uplink ergodic sum-rate maximization in OFDMA systems is considered. The general problem is formulated as a convex optimization problem and a dual solution is presented. The problem formulation is generalized to the case of utility maximization where the utility can be any function of rate. A suboptimal scheduling algorithm with low complexity is p...

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Projects (2)
Project
This projects formulates and deploys meta-statistical or machine learning framework that can be embedded within various computing systems. The proposed framework comprises carefully developed analysis criteria, thorough performance indicators, and combining formulations that captures the intended analysis and aids sound evaluations.