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E. Ahmed

Publications and source records attributed to E. Ahmed.

At least 19 recordsLinked to original sources

Malicious Package Detection using Metadata Information

Protecting software supply chains from malicious packages is paramount in the evolving landscape of software development. Attacks on the software supply chain involve attackers injecting harmful software into commonly used packages or libraries in a software repository. For instance, JavaScript uses Node Package Manager (NPM), and Python uses Python Package Index (PyPi) as their respective package repositories. In the past, NPM has had vulnerabilities such as the event-stream incident, where a malicious package was introduced into a popular NPM package, potentially impacting a wide range of projects. As the integration of third-party packages becomes increasingly ubiquitous in modern software development, accelerating the creation and deployment of applications, the need for a robust detection mechanism has become critical. On the other hand, due to the sheer volume of new packages being released daily, the task of identifying malicious packages presents a significant challenge. To address this issue, in this paper, we introduce a metadata-based malicious package detection model, MeMPtec. This model extracts a set of features from package metadata information. These extracted features are classified as either easy-to-manipulate (ETM) or difficult-to-manipulate (DTM) features based on monotonicity and restricted control properties. By utilising these metadata features, not only do we improve the effectiveness of detecting malicious packages, but also we demonstrate its resistance to adversarial attacks in comparison with existing state-of-the-art. Our experiments indicate a significant reduction in both false positives (up to 97.56%) and false negatives (up to 91.86%).

cs.CR

On evolutionary games with periodic payoffs

Two cases of evolutionary stable strategy with periodic payoffs are studied. The first is a generalization of Uyttendaele et al. The second is prisoner's dilemma with periodic payoff. It is shown that reducing the defection payoff by a periodic term is sufficient to introduce cooperation provided that the initial fraction of cooperators is greater than 0.6.

q-bio.PE

On Dynamical Cournot Game on a Graph

Cournot dynamical game is studied on a graph. The stability of the system is studied. Prisoner's dilemma game is used to model natural gas transmission.

cs.GT

On applications of Ulam-Hyers stability in biology and economics

We argue that Ulam-Hyers stability concept is quite significant in realistic problems in numerical analysis, biology and economics. A generalization to nonlinear systems is proposed and applied to the logistic equation (both differential and difference), SIS epidemic model, Cournot model in economics and a reaction diffusion equation. To the best of our knowledge this is the first time Ulam-Hyers stability is considered from the applications point of view.

nlin.CD

Lithographically and electrically controlled strain effects on anisotropic magnetoresistance in (Ga,Mn)As

It has been demonstrated that magnetocrystalline anisotropies in (Ga,Mn)As are sensitive to lattice strains as small as 10^-4 and that strain can be controlled by lattice parameter engineering during growth, through post growth lithography, and electrically by bonding the (Ga,Mn)As sample to a piezoelectric transducer. In this work we show that analogous effects are observed in crystalline components of the anisotropic magnetoresistance (AMR). Lithographically or electrically induced strain variations can produce crystalline AMR components which are larger than the crystalline AMR and a significant fraction of the total AMR of the unprocessed (Ga,Mn)As material. In these experiments we also observe new higher order terms in the phenomenological AMR expressions and find that strain variation effects can play important role in the micromagnetic and magnetotransport characteristics of (Ga,Mn)As lateral nanoconstrictions.

cond-mat.mtrl-sci

Survival May Not be for the Fittest (Lessons from some TV games)

In this paper we argue that biological fitness is a multi-objective concept hence the statement "fittest" is inappropriate. The following statement is proposed "Survival is mostly for those with non-dominated fitness". Also we use some TV games to show that under the following conditions: i) There are no dominant players. ii) At each time step successful players may eliminate some of their less successful competitors, Then the ultimate winner may not be the fittest (but close).

q-bio.PE

On differences between fractional and integer order differential equations for dynamical games

We argue that fractional order (FO) differential equations are more suitable to model complex adaptive systems (CAS). Hence they are applied in replicator equations for non-cooperative game. Rock-Scissors-Paper game is discussed. It is known that its integer order model does not have a stable equilibrium. Its fractional order model is shown to have a locally asymptotically stable internal solution. A FO asymmetric game is shown to have a locally asymptotically stable internal solution. This is not the case for its integer order counterpart.

q-bio.PE

On Modelling The Immune System as a Complex system

We argue that immune system is an adaptive complex system. It is shown that it has emergent properties. Its network structure is of the small world network type. The network is of the threshold type, which helps in avoiding autoimmunity. It has the property that every antigen (e.g.virus or bacteria) is typically attacked by more than one effector. This stabilizes the equilibrium state. Modelling complex systems is discussed. Cellular automata (CA) type models are successful but there are much less analytic results about CA than about other less successful models e.g. partial differential equations (PDE). A compromise is proposed

q-bio.PE

Towards understanding the immune system

It is proposed that using both self-non-self and danger theories give a better understanding of how the immune system works. It is proposed that comparing immune system to police force is useful in this case since police responds both to danger or damage signals and to foreign or suspicious behavior even if no danger signals existed. We also propose that due to low zone tolerance immunotherapy needs to be combined with another treatment method for cancer e.g. chemotherapy or/and radiotherapy to get a sufficient eradication of tumors. Finally we propose that fractional order differential equations are more suitable than the familiar integer order differential equations. A fractional order example of two immune effectors attacking an antigen is given.

q-bio.PE

The Role of Doppler Broadening in Electromagnetically Induced Transparency and Autler-Townes Splitting in Open Molecular Systems

We describe in this Letter how inhomogeneous line broadening affects the Autler-Townes (AT) splitting in a three level open molecular cascade system. For moderate Rabi frequencies in the range of 300 to 500 MHz the fluorescence line shape from the uppermost level |3> in this system depends strongly on the frequency ratio of the two laser fields. However, the fluorescence spectrum of the intermediate level |2> appears as expected. We provide a description of the conditions for optimally resolved AT splitting in terms of the probe laser/coupling field frequency ratio and laser propagation geometry based on our theoretical analysis of the Doppler integral. This is important for applications such as molecular angular momentum alignment as well as for the measurement of the transition dipole moment matrix element.

quant-ph

An Overview of Complex Adaptive Systems

Almost every biological, economic and social system is a complex adaptive system (CAS). Mathematical and computer models are relevant to CAS. Some approaches to modeling CAS are given. Applications in vaccination and the immune system are studied. Mathematical topics motivated by CAS are discussed.

nlin.AO

On complex adaptive systems and terrorism

Complex adaptive systems (CAS) are ubiquitous in nature. They are basic in social sciences. An overview of CAS is given with emphasize on the occurrence of bad side effects to seemingly wise decisions. Hence application to terrorism is given. Some conclusions on how to deal with this phenomena are proposed.

nlin.AO

On Multiobjective Evolution Model

Self-Organized Criticality (SOC) phenomena could have a significant effect on the dynamics of ecosystems. The Bak-Sneppen (BS) model is a simple and robust model of biological evolution that exhibits punctuated equilibrium behavior. Here we will introduce random version of BS model. Also we generalize the single objective BS model to a multiobjective one.

nlin.AO

On Persistence and Stability of some Biological Systems with Cross Diffusion

The concept of cross diffusion is applied to some biological systems. The conditions for persistence and Turing instability in the presence of cross diffusion are derived. Many examples including: predator-prey, epidemics (with and without delay), hawk-dove-retaliate and prisoner's dilemma games are given.

nlin.AO

Sato-Crutchfield formulation for some Evolutionary Games

The Sato-Crutchfield equations are studied analytically and numerically. The Sato-Crutchfield formulation is corresponding to losing memory. Then Sato-Crutchfield formulation is applied for some different types of games including hawk-dove, prisoner's dilemma and the battle of the sexes games. The Sato-Crutchfield formulation is found not to affect the evolutionarily stable strategy of the ordinary games. But choosing a strategy becomes purely random independent on the previous experiences, initial conditions, and the rules of the game itself. Sato-Crutchfield formulation for the prisoner's dilemma game can be considered as a theoretical explanation for the existence of cooperation in a population of defectors.

nlin.CG

On Spatial Asymmetric Games

The stability of some spatial asymmeric games is discussed. Both linear and nonlinear asymptotic stability of asymmetric hawk-dove and prisoner's dilemma are studied. Telegraph reaction diffusion equations for the asymmetric spatial games are presented. Asymmetric game of parental investment is studied in the presence of both ordinary and cross diffusions.

cond-mat.stat-mech