Ahmad Zahiri Mohamed Hassan | The University of Newcastle (original) (raw)

Papers by Ahmad Zahiri Mohamed Hassan

International Journal of Environmental Research and Public Health

Background: The purpose of this study is to explore the differences and similarities of EEG -base... more Background: The purpose of this study is to explore the differences and similarities of EEG -based neural emotional response toward flower arrangements (FAs) between the normal elderly (NE) and cognitively impaired elderly (CIE) in arranging flowers. Methods: The study participants included 16 elderly individuals: eight elderly people with normal cognitive function and eight elderly people with cognitive dysfunction. They were divided into two groups to arrange flowers, and six mood indicators (Engagement, Excitation, Focus, Interest, Relaxation and Stress) were measured with EEG before and after the experiment. Results: The similarities were that there was no significant difference in Excitement, Relaxation and Stress between pre-test and post-test for NE and CIE. The differences were that there was a significant difference on Engagement and Interest in CIE, and they both increased, but there was no difference with respect to them in NE. While there was a significant difference on ...

Proceedings of Shaikh Zayed Medical Complex Lahore

ABSTRACT. COVID-19 pandemic has caused significant morbidity and mortality around the world. The ... more ABSTRACT. COVID-19 pandemic has caused significant morbidity and mortality around the world. The disease severity ranges from mild upper respiratory infection to severe lower respiratory and cardiac illness. Acute respiratory distress syndrome (ARDS) is the most serious complication and results in diffuse inflammatory alveolar damage, respiratory failure, and death. Components of the Renin -Angiotensin-Aldosterone -System (RAAS) are involved in an inflammatory reaction in the lungs. Various studies have shown that blocking RAAS peptides in the lungs especially angiotensin-converting enzyme (ACE) and type-1 angiotensin receptor (ATR1) reduces lung injury, improves respiratory function and is associated with better clinical outcomes in the COVID-19 patients. We suggest that angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) – drugs that block RAAS peptides – be considered for a repurposed use in COVID-19 induced lung injury.

This paper deals with the quantitative assessment of the unreliability of migration between habit... more This paper deals with the quantitative assessment of the unreliability of migration between habitat patches in terms of ecological corridor unreliabilities that are known only with uncertainty. The corridor unreliabilities are treated herein as log-normally distributed random variables, and hence the assessment becomes a doublystochastic one. The paper utilizes the multi-affine nature of the reliability function in deriving exact formulas for the mean and variance of the system unreliability, as well as accurate formulas for its third and fourth central moments. These formulas involve the nominal values of certain partial derivatives. The multi-affine nature is also beneficial in the development of an alternative method that involves powers rather than derivatives. These two analytical methods of moments agree reasonably with one another and with the results of Monte Carlo simulations. Several test cases are considered for typical ecology problems with corridor unreliabilities that ...

or library professionals to gain a deeper understanding of the case for intellectual freedom in a... more or library professionals to gain a deeper understanding of the case for intellectual freedom in all library environments. From advice on planning the physical space of a library, collection development (including physical and virtual content), Internet access, the library as a public space, and technology and all of its various components including social networking, she has made the case for intellectual freedom clear. Be it a lecture from the Iranian president Mahmoud Ahmadinejad, a student viewing pornography on a library workstation, or students simply stopping by to check their e-mail, Ms. Jones makes the case that the environment of the library has changed to more fully protect intellectual, and personal, freedom. The library is no longer the stiff collared version of yesterday, but is now a place for intellectual challenge, freedom of speech, comfy couches, coffee shops, and flips flops. This most current ALA release allows the reader to delve deeper into the folds of academi...

Ordinary Jerusalem, 1840-1940

This is an open access chapter distributed under the terms of the prevailing CC-BY-NC-ND License ... more This is an open access chapter distributed under the terms of the prevailing CC-BY-NC-ND License at the time of publication.

Sensors

Closed-form evaluation of key performance indicators (KPIs) of telecommunication networks help pe... more Closed-form evaluation of key performance indicators (KPIs) of telecommunication networks help perform mathematical analysis under several network configurations. This paper deals with a recent mathematical approach of indefinite quadratic forms to propose simple albeit exact closed-form expressions of the expectation of two significant logarithmic functions. These functions formulate KPIs which include the ergodic capacity and leakage rate of multi-user multiple-input multiple-output (MU-MIMO) systems in Rayleigh fading channels. Our closed-form expressions are generic in nature and they characterize several network configurations under statistical channel state information availability. As a demonstrative example of the proposed characterization, the derived expressions are used in the statistical transmit beamformer design in a broadcast MU-MIMO system to portray promising diversity gains using standalone or joint maximization techniques of the ergodic capacity and leakage rate. ...

IEEE Access

In fifth generation (5G) networks, the densification of small base stations in the coverage regio... more In fifth generation (5G) networks, the densification of small base stations in the coverage region of macro base station (MBS) leads to significant inter-cell interference (ICI). Similarly, drones (a.k.a. unmanned aerial vehicles) have a diverse scope in multifarious 5G assisted applications and, therefore, cause considerable drones interference (DI) as a result of excessive drone usage. This paper investigates the bottleneck uplink (UL) coverage performance of the MBS edge users in the presence of ICI and DI. To mitigate both ICI and DI, we use an efficient resource allocation scheme known as reverse frequency allocation (RFA). Moreover, we use decoupled association (DeCA) in place of coupled association to further improve UL signal-to-interference ratio. The results depict that RFA in conjunction with DeCA overpass all other techniques in terms of improved UL coverage performance because of effective DI and ICI mitigation.

Energies

This paper uses a two-layered soft voting-based ensemble model to predict the interfacial tension... more This paper uses a two-layered soft voting-based ensemble model to predict the interfacial tension (IFT), as one of the transformer oil test parameters. The input feature vector is composed of acidity, water content, dissipation factor, color and breakdown voltage. To test the generalization of the model, the training data was obtained from one utility company and the testing data was obtained from another utility. The model results in an optimal accuracy of 0.87 and a F1-score of 0.89. Detailed studies were also carried out to find the conditions under which the model renders optimal results.

Proceedings of XII Advanced Computing and Analysis Techniques in Physics Research — PoS(ACAT08)

Telecommunication Systems

This paper exhibits a primer on the use of modern system reliability techniques on several import... more This paper exhibits a primer on the use of modern system reliability techniques on several important topologies of small-cell deployment in multi-tier dense cellular networks. We synthesize a network into several subnetworks and use outage probability as a performance metric to formulate the small-cell deployment problem in the Boolean domain by means of an indicator function. The methodology employed herein includes disjointness for logically added expressions, arriving at a probability ready expression, and a transformation to the probability domain on a one-to-one basis by replacing indicator Boolean variables by their expectations and replacing logical operations by their arithmetical counterparts. This work also presents a systematic procedure of computing several reliability metrics such as the useful redundancy region, mean-time-to-failure, importance measures of the links, and quantification of uncertainty in system reliability as a function of uncertainties in link reliabilities by considering both identical and non-identical link failures. Non-linear algorithms are also tested on the optimization problem that minimizes system unreliability. We contribute to the important issue of analyzing small-cell deployment by providing exact system reliability metrics and hence open a new frontier for software defined networks controllers.

IEEE Transactions on Computers

This paper studies the problem of efficiently utilizing hybrid memory systems, consisting of both... more This paper studies the problem of efficiently utilizing hybrid memory systems, consisting of both Dynamic Random Access Memory (DRAM) and novel Non-Volatile Memory (NVM) in database management systems (DBMS) for online analytical processing (OLAP) workloads. We present a methodology to determine the database operators that are responsible for most main memory accesses. Our analysis uses both cost models and empirical measurements. We develop heuristic decision procedures to allocate data in hybrid memory at the time that the data buffers are allocated, depending on the expected memory access frequency. We implement these heuristics in the MonetDB column-oriented database and demonstrate performance improvement and energy-efficiency as compared to state-of-the-art application-agnostic hybrid memory management techniques.

Wireless Personal Communications

This communication attempts to characterize the performance metrics of downlink Massive MU-MIMO s... more This communication attempts to characterize the performance metrics of downlink Massive MU-MIMO systems impaired by cochannel interference and additive noise over a Rayleigh fading environment. We obtain close-form solutions for the probability density function of signal-to-interference-plus-noise ratio (SINR) and the sum ergodic capacity. The proposed work structures SINR in a quadratic form and thereby imposes a condition on its signal and interference power for a large transmit antenna diversity order; the conditional form is then analyzed using a distance correlation metric. Eventually, the sum ergodic capacity is expressed in a close-form by means of a residue theory approach and validated using the Monte Carlo simulation means.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES

In this paper, we characterize the performance metrics of a multiuser multipolarized antenna syst... more In this paper, we characterize the performance metrics of a multiuser multipolarized antenna system in a Rayleigh fading channel. We start by formulating a downlink system model that features a multiuser scenario in the presence of additive noise and a multipolarized antenna system; this is followed by evaluation of the outage probability in closed form. This is done by deriving the cumulative distribution function (CDF) of the signal-to-interference-plusnoise ratio using the approach of the ratio of indefinite quadratic forms. We thereby characterize the gradient of this CDF with respect to the combining vectors. Eventually, we obtain the optimum combining vectors by minimizing the outage probability via interior-point optimization technique. Simulation and theoretical results of our analysis are closely matched, which validates our analysis. Our findings suggest that the performance of the triple polarized antenna is better than that of the dual polarized antenna system for low signal-to-noise ratio (SNR) values in terms of outage probability; this situation, however, reverses for high SNR value.

IET Communications

Here, the authors develop a method of simultaneous optimisation of precoder and equaliser for the... more Here, the authors develop a method of simultaneous optimisation of precoder and equaliser for the multi-user multiple-input multiple-output (MIMO) system by minimising outage probability. In order to do that, the authors first characterise the signal-to-interference-plus-noise ratio of downlink multi-user MIMO system in the presence of both multi-user interference and self-interference. The closed-form expression for the outage probability is derived in terms of the eigenvalues of an indefinite weight matrix of a quadratic norm. Next, the authors develop an active-set algorithm-based precoder and equaliser by minimising the derived outage probability expression. This work investigates the effect of various system parameters such as the number of users, the number of multi-path channels, the number of transmitting and receiving antenna elements, and the additive noise variance on the outage probability and bit error rate. Simulation results validate the theoretical analysis for multiple system configurations. Lastly, the authors show that the designed precoder and equaliser improves the overall system performance.

2015 International Conference on Parallel Architecture and Compilation (PACT), 2015

SpringerPlus, 2016

Background Scientific research desires various methodologies to collect quality data, analyze it ... more Background Scientific research desires various methodologies to collect quality data, analyze it according to the required parameters and interpret the results of the data collected to formulate new tools, revise the existing guidelines, or simply verify current understandings. Studying trends in research across the regions or over a period of time in same geographic location by representing degree of variations on weighing various entities, which is mostly affected by evolution in knowledge and cultural trends besides other social factors, can give us a clue on preferences of the studied era or locality or both.

2012 IEEE Aerospace Conference, 2012

As aero-engines operate, metal and other material particles are removed from the contact surfaces... more As aero-engines operate, metal and other material particles are removed from the contact surfaces and are carried away in the flow of lubricating oil. Spectrometric Oil Analysis Program (SOAP) is a powerful tool for elemental analysis of structural metals in the lubricating oils circulating inside the machine, and is suitable for determining wear metal quantity, elemental composition, rate of wear

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