PhD
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/50
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Space Spectral Time Fractional Finite Difference Method along with Stability Analysis for Fractional Order Nonlinear Wave Equations(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Muhammad Sarmad Arshad; SP13-PMATH-004; Dr. Ayesha Sohail; LHR TP 5299In this work, nonlinear partial differential equations governing the obscure phenomena of shallow water waves are discussed. Time fractional model is considered to understand the upcoming solutions on the basis of all historical states of the solution. A semi-analytic technique, Homotopy Perturbation Transform Method (HPTM) is used in conjunction with a numerical technique to validate the approximate solutions. With the aid of graphical interpretation, the favorable wave parameters, to avoid wave breaking are estimated. Afterwards, dynamical analysis of fractional order Schr dinger equation governing the optical wave propagation is reported in detail. The validity criteria for the application of the semi-analytic asymptotic methods are exploited. Comparison between the solutions obtained by the two asymptotic techniques, that is, the Fractional Homotopy Analysis Transform Method and the Optimal Homotopy Analysis Method is performed to select the most accurate technique for the stated problem. Space spectral analysis with integrating factor technique and time fraction finite difference method have been implemented to study the pressure waves propagating in bubbly fluids as well as nonlinear phenomena of plasma waves. Dynamical analysis of acoustic/pressure waves propagating in bubbly fluids is of great significance. Such flows arise in many engineering problems including sonochemistry, sonochemical reactors, cavitation around hydrofoils and ultrasonic propagation in medicine and biology. Fractional approach for modeling the propagation of the pressure waves in liquids containing a large number of tiny gas bubbles is proposed. Moreover, numerical solution of the fractional order Modified Korteweg-de Vries equation governing the dynamics is approximated using a novel space spectral time fractional finite difference tool. A spectral technique for space and a multi-step finite difference scheme for time are designed and implemented. The spatial spectral discretization error and the stability bounds are discussed. The nonlinear phenomena of plasma waves are well demonstrated with the aid of graphical analysis. Stability analysis of integer and fractional order KdV equations have been discussed quantitatively with the help of Evans function approximation.Item T-Norms Based Fuzzy Ordering And Their Application(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Atiq-Ur-Rehman; SP12-PMATH-001; Dr Samina Mazhar; LHR TP 4874This research work focuses on T-transitive fuzzy orderings, their mathematical structures and representation results on these orderings. We have shown that the consistent nature of a fuzzy preference relation has direct relationship with its being more or less T-transitive. After handling this task, some work is done on applications of T-transitivity in the area of preference modeling. Here we have presented some new algorithms to complete an incomplete fuzzy preference relation. These algorithms are based on T-transitivity of a given fuzzy relation. This work has its roots in multi criteria and multi agent decision making. The target is to achieve a ranking among alternatives while incomplete information is provided by the judges about criteria of selection and pair wise preferences amongst alternatives. We have further extended these results to their interval valued versions where the consistent and consensus degrees are also accommodated. The theory and algorithms provided so far are then used to solve real life problems of industry i.e., the problem of supplier selection in the supply chain management where the successful implementation of the results is demonstrated.Item Particle Creation with Adiabatic Transformation Through Thermodynamic Perspective in Modified Theories(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Mubashira Rasheed; FA17-RMT -014; Dr. Muhammad Zubair; LHR TP 5651Modified gravitational theories play significant role to discuss many con stituent of the accelerated phase of our universe for last few decades. A large numberofdifferent techniques in modified theories are proposed to sort out the cosmological problem. Weanalyzedopenirreversiblethermodynamicsinthescenarioofparticle cre ation for modified theory of gravity known as f(G,T) gravity theory, in which the generic function defines the coupling between GB invariant G and trace of the EMT with non-zero divergence. We discussed the generalized conser vation equation which involves additional contribution from matter geome try coupling for irreversible matter creation process with the help of general ized "second law of thermodynamics" in the light of the “Friedmann-Lematre Robertson-Walker" FLRW space time. Particle creation rate, number of particle creation, creation pressure, entropy production rate, and temperature for this theory have been formulated by choosing some particular model of f(G,T), which help us to explore the particle creation in a significant way. We also discussed non-minimal F(R,T,Q) theory of gravity where (R, T, Q are ricci scalar, trace of EMT and interaction of Ricci tensor and non-minimal coupling of Ricci scalar respectively, and Q = RαβTαβ) is the interaction of Ricci tensor and EMT. Due to the non-minimal coupling of gravity and geometry an extra force present which is perpendicular to four velocity. We also formulated some explicit results of created particle from gravitational field to the created ix matter such as particle creation rate, pressure of created particle and entropy with respect to time variation through irreversible thermodynamics interrelated with adiabatic transformation in the context of FLRW space time. We consid ered the dust universe i.e., P = 0 and the scale factor by power law a(t) = tm to precise our results. It is observed that in this procedure a large amount of co-moving entropy has been generatedItem New Measures of Intuitionistic Inclusion and Similarity with Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Madiha Qayyum; SP13-PMATH-002; Dr. Samina Mazhar; LHR TP 4873Similarity and inclusion are two most important conceptual ways for looking at any possible relationships between objects (sets). A similarity measure is used for estimating the degree of resemblance/similarity between two objects while an inclusion measure expresses the degree to which one of the two is covered by the other one. In this dissertation, we have presented two different yet equally important approaches of defining similarity and inclusion measures for intuitionistic fuzzy sets. The first approach can be regarded as a logical approach implanting intuitionistic fuzzy implication, bi-implications and t-norms while the second one is a purely set theoretic approach having cardinalities and sets operations involved in its construction. In the logical approach, the degree of inclusion/ similarity was obtained by composing the intuitionistic logical operators (implications and bi-implications) with fuzzy measures on intuitionistic fuzzy sets. For this purpose we initially defined some new normal fuzzy measures on intuitionistic fuzzy sets along with a class of scalar cardinality measure for intuitionistic fuzzy sets. Later, we introduced different classes of intuitionistic fuzzy bi-implication operators having axiomatic as well as constructive approaches. A study on the properties of these bi-implication operators by utilizing Lukasiewicz intuitionistic fuzzy implicator revealed some remarkable results. The intuitionistic fuzzy bi-implication operators along with new defined fuzzy measures gave rise to multiple classes of intuitionistic fuzzy bi-implicator based similarity measures for intuitionistic fuzzy sets. Also the same normal fuzzy measures were employed to obtain the degree of inclusion between two intuitionistic fuzzy sets when composed with intuitionistic fuzzy implication operators. The new implication based classes of inclusion and similarity measures fulfilled almost all of the universally accepted criteria’s. In the set theoretic approach, we employed one of the members of new introduced scalar cardinality of intuitionistic fuzzy sets to construct a four parametric family of cardinality based similarity and inclusion measures. Both of these parametric families, xi for different combinations of parameters, generated intuitionistic fuzzy versions of some of the famous crisp measures of time. Lastly, the utility of the new measures (similarity, inclusion, cardinality and others) of intuitionistic fuzzy sets introduced in this work is exhibited by utilizing them as a part of solution techniques to the problems arising in real life situations.Item Generalizations of Cyclic Refinements of Jensen’s Inequalities(Library Information Services COMSATS University Islamabad Lahore Campus, 2020) Nasir Mehmood; FA14-PMATH-005; LHR TP 7451; Dr. Saad Ihsan ButtIn recent years, the concept of convex functions has been generalized extensively. Applications of convex functions are widely seen in many areas of modern analysis. Convex functions also have significant relation with the theory of inequalities and many useful inequalities are the result of the applications of convex functions. The Jensen's inequality has tremendous implications in many fields of modern analysis. It helps computing useful upper bounds for several entropic measures used in information theory. We consider discrete and continuous cyclic refinements of Jensen's inequality and extend them from convex to higher order convex function by using new Green functions introduced by us and employing different interpolating polynomials and identities. We formulate monotonicity of the linear functionals for nconvex functions at a point. We calculate some new Grüss and Ostrowski type bounds. As an application of our obtained results we give new bounds for Shannon, Relative and Zipf-Mandelbrot entropies.Item Koszul Loops Algebraic And Topological Description(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Muhammad Nadeem; SP13-PMATH-003; LHR TP 6346; Dr. Sarfraz AhmadIn this thesis we explore interactions between three well established fields namely Algebra, Combinatorics and Chemistry. Main idea is to solve complicated problems in one field by using comparatively easy approaches of the second. We work it out in three different ways. In the first part, we explore chemical properties of some compounds using combinatorial techniques. In recent days atomic properties of chemical structures are intensively explored using results of graph theory depending upon degrees and distances of the associated graphs. In particular, we work on one of the interesting classes of degree based indices, namely, the Zagreb indices. These indices are very useful in QSPR and QSAR studies. We compute Zagreb index, its co index and multiple index for the topological descriptors of 2-dimensional silicon carbons 𝑆𝑖2𝐶3 − 𝐼𝐼𝐼, � �𝑖𝐶3 − 𝐼𝐼𝐼. On the other hand it is of great importance to explore the irregularity of a graph in Chemistry, Pharmacy and Bio technology. We compute irregularity, total irregularity, variance and irregularity index of some networks including (𝐻𝐻𝐶 − 1), (𝐻𝐻𝐶 −2),(BSN−1),(BSN−2) and nanocone 𝑁𝐶𝑘[𝑛]. In the second part we focus on connections between Algebra and Combinatorics. We construct a family of Wilson loops of different orders with the help of additive and multiplicative groups. We associate these newly obtained algebraic structures to the graphs through link labeling. As a main result of this session we prove that the Latin square of the Wilson loop is connected with a bipartite graph. Similarly its normal sub loop of the Wilson loop is associated with the class of star graphs. Let 𝑅 = 𝑘[𝑥1,…,𝑥𝑛] be a polynomial ring in 𝑛 variables. There is one to one correspondence between set of all square free monomial ideals in 𝑅 and set of all simplicial complexes over 𝑛 vertices. The 𝑓- and ℎ-vectors of the simplicial complex ∆ play an important role to describe algebraic properties of the associated square free monomial ideal 𝐼∆. Let ∆𝑠𝑢𝑏 be subdivided simplicial complex obtained from ∆. In the last part of this thesis, we discuss the transformation maps sending the ℎ-vectors of the simplicial complex ∆ to the ℎ-vectors of the subdivided simplical complex ∆𝑠𝑢𝑏. In the end we give algebraic applications describing the primary decomposition of an ideal 𝐼𝑃 associated to the partially ordered set = 𝐶𝑖 × 𝐶𝑗 , where 𝐶𝑖 is the chain 1 < ...<Item Predictive Modeling of Diabetes Classification using Artificial Neural Networks(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Muhammad Amin; FA23-RMT-017; Dr. Muhammad Rafiullah; LHR TP 9764Diabetes mellitus is a chronic disease that has become a major global public health challenge. Timely and accurate prediction not only aids in immediate treatment but also plays a crucial role in formulating effective strategies. In this research, we compare the prediction of diabetes using two popular neural network models Multi-Layer Perceptron (MLP) and General Regression Neural Network (GRNN). This analysis is based on the PIMA Indian Diabetes Dataset, which contains medical information of female patients, including glucose levels, BMI, insulin amount, age, etc. In this research, the dataset underwent stages of cleaning, normalization, and division into training and testing sets. Then, the mathematical details of the MLP and GRNN models were described, which included forward propagation, activation functions, and loss formulas. The MLP model used two hidden layers with ReLU and Sigmoid activation functions, while the GRNN model used Gaussian radial basis functions and Euclidean distance. After training, the performance of both models was evaluated using metrics such as accuracy, confusion matrix, and ROC-AUC, revealing that both models proved effective in predicting diabetes. However, GRNN demonstrated better overall performance due to its non-repetitive structure and smooth results, while MLP exhibited more effective adaptation thanks to fast computation and deep network architecture, making it suitable for large and complex data. This research indicates that if ANN models are designed and configured correctly, they can help in the timely and effective diagnosis of diabetes. This analysis provides guidance to healthcare professionals and data scientists in selecting appropriate models.Item Mathematical Modeling and Stability Analysis of Monkey Pox Transmission in Rodents and Humans(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Aqsa Shehzaadi; FA23-RMT-006; Dr. Yousaf Bhatti; LHR TP 9754In this thesis, deterministic and stochastic mathematical models for the dynamics of monkey pox transmission across rodent and human populations are developed and analyzed. The study builds systems of nonlinear differential equations to describe disease progression and control strategies, such as vaccination and treatment, using compartmental modeling techniques like SIR and SEIR. Important epidemiological characteristics like interspecies transmission, disease-induced mortality, and incubation times are included in the models. To evaluate the stability of endemic and disease-free equilibria, analytical techniques such as basic reproduction number (R₀) analysis and Jacobian matrices are used. Moreover, random environmental and demographic perturbations are taken into account via stochastic differential equations, and stochastic Euler, Runge-Kutta, and NSFD methods are employed for numerical simulations. The results demonstrate the importance of intervention tactics in lowering the incidence of monkey pox and the usefulness of stochastic modeling in comprehending intricate epidemic dynamics in the face of uncertainty.