Sree Hari Rao Vadrevu

Foundation for Scientific Research and Technological Innovation Hyderabad

Banks face various risks which may be broadly classified as Credit, Market and Operational risks. The Basel committee for banking supervision provides guidelines for measuring operational risk capital using three different approaches namely Basic Indicator Approach (BIA), Standardised Approach (SA), usually referred to as TSA and Advanced Measureme...

This article presents the state-of-the-art account of the vital issues related to the COVID-19 pandemic. It also provides a discussion on the failure of the methodologies in vogue. The surveillance of the disease, besides the dynamics of transmission and the disease management of the COVID-19, are the main concerns of this work. Based on our observ...

In this survey paper we discuss a class of dynamical systems giving rise to three types of bifurcations: Hopf bifurcation, Turing bifurcation and Zip bifurcation. We present methods from dynamical systems theory that help to classify the studied bifurcations. As application of the proposed methods, a class of predator-prey systems are analyzed. Spe...

In this paper we have considered a three dimensional system of partial differential equations to model the dynamical interactions of two predators competing for a single prey. The model is developed by introducing cross diffusion in such a way as to take into account the migratory strategy adopted by the predators, who take advantage of the defense...

This article purports to present a systematically developed survey on the influence of zones of no activation/dead zones in bidirectional associative memory (BAM) neural networks. The modeling effort based on the concept of dead zones is capable of explaining very intricate phenomena concerned with the functioning of the human brain. Activation dyn...

We have proposed a three-species hybrid food chain model with multiple time delays. The interaction between the prey and the middle predator follows Holling type (HT) II functional response, while the interaction between the top predator and its only food, the middle predator, is taken as a general functional response with the mutual interference s...

In this paper we study the interactions among two species of predators and one single species of prey populations, under a more generalized functional response arising out of the competition. The models presented in this research for these species exhibit rich dynamics for varying values of the vital parameters involved. Conditions for the existenc...

Food uptake ability of higher trophic level species are more complicated and interesting due to their choice and availability of food and consequently their growth and also the effect of top predator interference on the dynamics of a tritrophic food chain model. In this paper, we consider the general framework for calculating the stability of equil...

The influence of time varying inputs on a two layer neural network involving transmission delays is studied in this paper. The asymptotic behavior of solutions of the system is studied for a variety of input functions. Conditions for solutions of a system with time varying inputs to approach the solutions (including equilibrium solutions) of the co...

It is well-known that any risk management activity is a cost to the organization. However, optimized risk management practices satisfy regulatory capital requirements and gain the confidence of investors who take calculated risks. A bank's risk management division will generate a profit if it can develop methodologies to decrease the nonworking reg...

Seed storage proteins comprise a major part of the protein content of the seed and have an important role on the quality of the seed. These storage proteins are important because they determine the total protein content and have an effect on the nutritional quality and functional properties for food processing. Transgenic plants are being used to d...

Credit risk estimation and bankruptcy prediction methods have utilized Altman’s Z-score method for the last several years. It is reported in many studies that Z-score is sensitive to changes in accounting figures. Researchers have proposed different variations to conventional Z-score that can improve the prediction accuracy. In this paper, we devel...

A third-order system of ordinary differential equations, modelling two predators competing for a single prey species, is analysed in this paper. A delay term modelling the delayed logistic growth of the prey is included. Fixed points of the system are identified, and a linearized stability analysis is carried out. For some parameter regime, there e...

Coronary heart disease (CHD) caused by hardening of artery walls due to cholesterol known as atherosclerosis is responsible for large number of deaths worldwide. The disease progression is slow, asymptomatic, and may lead to sudden cardiac arrest, stroke, or myocardial infraction. Presently, imaging techniques are being employed to understand the m...

Understanding the dynamics of an infectious disease holds the key for designing effective control strategies from public health perspective. There are two approaches for modeling the dynamics of epidemics, namely (1) dynamical mathematical modeling and (2) incidence data modeling. Recent mathematical models are helpful in understanding the spread (...

Dengue fever is a flu-like illness spread by the bite of an infected mosquito and is fast emerging as a major public health concern. Timely and cost-effective diagnosis would reduce the mortality rates besides providing better grounds for clinical management and disease surveillance. Identifying the clinical features for early diagnosis of dengue w...

Avian Influenza, commonly known as Bird Flu, is an epidemic caused by H5N1 Virus, that primarily affects birds such as chickens, wild water birds, ducks, and swans etc. On rare occasions, pigs and humans will also be affected with this virus In recent years this epidemic has emerged as a major global health concern. The present chapter is aimed at...

Despite great advances in public health worldwide, insect vector-borne infectious diseases remain a leading cause of morbidity and mortality. Diseases that are transmitted by arthropods such as mosquitoes, sand flies, fleas, and ticks affect hundreds of millions of people and account for nearly three million deaths all over the world. In the past t...

Extraction of customer behavioral patterns is a complex task and widely studied for various industrial applications under different heading viz., customer retention management, business intelligence and data mining. In this paper, authors experimented to extract the behavioral patterns for customer retention in Health care insurance. Initially, the...

This issue marks the beginning of the IEEE Transactions on Neural Networks and Learning Systems (TNNLS). By adding "Learning Systems" to the title, we now state explicitly the scope of the TRANSACTIONS to include neural networks as well as related learning systems. This issue marks a new era in the history of our TRANSACTIONS. The TRANSACTIONS is n...

Identification of the influential clinical symptoms and laboratory features that help in the diagnosis of dengue fever (DF) in early phase of the illness would aid in designing effective public health management and virological surveillance strategies. Keeping this as our main objective, we develop in this paper a new computational intelligence-bas...

In this paper we study the influence of weak Allee effect in a predator-prey system model. This effect is included in the prey equation and we determine conditions for the occurrence of Hopf bifurcation. The stability properties of the system and the biological issues of the memory and Allee models on the coexistence of the two species are studied....

Paratransgenesis is an approach to reducing arthropod vector competence using genetically modified symbionts. When applied to control of Chagas disease, the symbiont bacterium Rhodococcus rhodnii, resident in the gut lumen of the triatomine vector Rhodnius prolixus (Hemiptera: Reduviidae), is transformed to export cecropin A, an insect immune pepti...

A model for the prediction of fatigue life based on the statistical distribution of pores, intermetallic particles and grains is presented here. This has been applied to a cast Al alloy A206 before and after friction stir processing (FSP). The model computes the probability of initiating a small crack based on the probability of finding combination...

In this paper, activation dynamics of complex-valued neural networks are studied on general time scales. Besides presenting conditions guaranteeing the existence of a unique equilibrium pattern, its global exponential stability is discussed. Some numerical examples for different time scales are given in order to highlight the results. KeywordsTime...

In this paper, we propose a realistic mathematical model taking into account the mutual interference among the interacting populations. This model attempts to describe the control (vaccination) function as a function of the number of infective individuals, which is an improvement over the existing susceptible–infective epidemic models. Regarding th...

In this article we present a novel tool that renders efficient classification of epidemiological data of vector-borne diseases. This algorithm has been applied on the data of the Filariasis disease and the results are compared with the well-known k-nearest neighbor algorithm.

We consider a potential with two parameters, involving the amplitude and the scale, which adequately represent the real world phenomena concerning the receptor cells in a simple form. This potential also exhibits a sort of “electrical neutrality” making the total effect zero. Mathematically, this requires the potential V(x)=(x2−1)exp(−x2/2), satisf...

Quite often students pursuing a course in mathematics face an embarrassing situation when a nonmathematician raises the question of applicability of mathematics to real-world problems. This may be due to the abstractness of mathematical theory that the readers come across. Further, it is generally viewed that mathematical models are built and the t...

For a biologist, chemostat is a replica of a simple lake. Thus, chemostat models are widely used to represent the growth of species in a lake where the organisms such as algae feed on growth-limiting nutrients such as nitrogen and phosphorus. The analogy between a simple lake and a chemostat becomes clear from the Table 2.1. Availability of a nutri...

Nature generally checks the unlimited growth of populations through many ways. One of the important factors that influence the growth of populations is the “finite carrying capacity” of the environment in which the species grow. The term carrying capacity is a parameter representing the resources, e.g., food, space, sunlight, etc. on which the spec...

The study of Example 2.42 has revealed that the mechanisms introduced in Chaps. 4-6 have definitely contributed toward the stability of the positive equilibrium whose status is undecided as far as model equations (2.81) are concerned.We shall now see the strength of these mechanisms when the system given by model (2.81) is established to exhibit th...

Excess consumption of nutrient may lead to abnormalities in the growth of biotic species. Further, excess consumption of nutrient should be controlled in order to utilize the resources properly, especially, when the resources are not abundantly available (limited nutrient). When the populations are at equilibrium or once they are completely fed, th...

Often, the microorganisms grownot only in the growth medium (container), but also along the walls of the container. This is either due to the ability of the microorganisms to stick on to the walls of the container or the flow rate is not fast enough to wash these organisms out of the system. This phenomenon is generally referred to as the “wall gro...

Until now, we have studied the stability, instability, and oscillatory behaviors of the 5 system (2.81) (Chap. 2) and mechanisms that can regulate the instability charac- 6 teristics of the systems in Chaps. 4-7. We have observed that due to the variations 7 in nutrient supply (inflow) and washout (outflow), the system is subject to disturbances. I...

Themain theme of this chapter is to study the instability characteristics of the model equations induced by time delays. We have established in Chap. 1 that the basic model (1.5) is structurally stable. Also when the average time delays are sufficiently small, results are obtained for the boundedness of solutions, and local and global stability of...

This article envisages development of global stability conditions for the basic chemostat model. Also the existence and uniqueness of solutions for the model equations are established for a general uptake function under conditions weaker than the Lipschitz condition. Comparisons are made with some existing results.

We propose a new mathematical model for aquatic populations. This model incorporates mutual interference in all the three populations and an extra mortality term in zooplankton population and also taking into account the toxin liberation process of TPP population. The proposed model generalizes several other known models in the literature. The prin...

Mathematical modeling in the biological sciences is growing exponentially because the general area provides exciting problems from biology to medicine, and this goes under the name mathematical biology. Moreover, models of the growth of microorganisms have become very popular since mathematical predictions can be tested in the laboratory employing...

Avian influenza, commonly known as bird flu, is an epidemic caused by H5N1 virus that primarily affects birds like chickens, wild water birds, etc. On rare occasions, these can infect other species including pigs and humans. In the span of less than a year, the lethal strain of bird flu is spreading very fast across the globe mainly in South East A...

In this paper activation dynamics of a complex valued neural network has been studied. Sufficient conditions for global exponential stability of a unique equilibrium are obtained. Our results show that in the serial mode of operation, the network converges to a stable state.

In this article, we present a mathematical model of a unilingual society developing in to a bilingual society. We formulate, analyze the model and interpret the results of the analysis. The model is based on a two language policy motivated by the cultural and historical back ground of India.

This Letter deals with the concepts of co-operation and support among neurons existing in a network which contribute to their collective capabilities and distributed operations. Activational dynamical properties of these networks are discussed.

This paper deals with the problem of identification of unknown parameters and time-delay of dynamical systems. A polynomial function is employed to modify the structure of the system and subsequently suitable algorithms for identifying the parameters of time-lag systems are developed using neural networks. Illustrative examples for identification o...

Existence of coupled periodic quasi-solutions for system of second order differential equations are discussed by combining the method of upper and lower solutions and Lyapunov Schmidt method. The results corresponding to homogeneous Neumann boundary conditions are also given.

Several psychiatric conditions are associated with frequent fluctuations of affect. In this study, we propose a new technique to uniformly score depression and mania objectively and use a new mathematical technique to model the frequent fluctuations in mood using simulated data. Our main aim is to examine the usefulness of this measure for evaluati...

In this paper we have analyzed a limited nutrient–consumer dynamic model involving distributed time delays both in material recycling and growth response of consumer. It is established that the system exhibits instability characteristics due to the presence of time delays. Three different types of naturally feasible bio-control mechanisms are propo...

A limited nutrient consumer hybrid system which exhibits rich dynamics such as stability, instability and oscillatory characteristics is considered. The parameters that strongly influence the behavior of the system are identified and are estimated using the techniques of dynamic optimization. Two independent bio-control mechanisms are introduced in...

A nutrient-consumer model involving a distributed delay in material recycling and a discrete delay in growth response has been analysed. Various easily verifiable sets of sufficient conditions for global asymptotic stability of the positive equilibrium solution of the model equations have been obtained and the length of the delay in each case has b...

A mathematical model describing limited nutrient-consumer dynamics with both nutrient input and its supply rate varying with respect to time and involving distributed time delays both in nutrient recycling and biotic species growth has been analyzed. The existence of periodic solutions to the model equations when both the nutrient input and its sup...

Two models of ratio-dependent prey–predator dynamical systems are considered. Independent sets of sufficient conditions for global asymptotic stability of the positive equilibrium solution of the model equations in each case have been obtained. An example is provided for illustration and to compare with earlier results.

This paper deals with the problem of identification of the unknown parameters of a dynamical system. Our work in this paper largely simulation related, follows the approach suggested by Kim and Lee [IEEE Int. Conf. Neural Networks (1993) 438–443] and it depends on the introduction of auxiliary polynomial. The merit of our work lies on the facts tha...

In this paper we present the latest developments in the chemostat models involving time delays. The article envisages the development of a basic chemostat model into a model that explains the growth in a lake as well.

A chemostat model with distributed time delays both in material recycling and biotic species growth has been considered. A concept of wall growth is introduced and its effect on the global stability of the positive equilibrium is discussed. Several easily verifiable independent sets of global stability conditions are presented.

A bi-directional associative memory network with continuously distributed delays has been considered and the global exponential convergence analysis of its activations has been studied. Two easily verifiable sufficient conditions have been presented for global exponential stability of its equilibrium pattern using the Lyapunov function theory and i...

In this paper we derive a mathematical model for the Inverted pendulum

A mathematical model describing the dynamical interactions of bidirectional associative memory networks involving transmission delays is considered. The influence of a dead zone or a zone of noactivation on the global stability is investigated and various easily verifiable sets of sufficient conditions are established. The asymptotic nature of solu...

In this paper global asymptotic stability and asymptotic behaviour of solutions of nonlinear delay difference equations has been studied and a few sets of sufficient conditions for global asymptotic stability are derived.

A model for cellular neural networks involving time delays is considered. Various sets of sufficient conditions, both delay dependent and independent, for the global asymptotic stability of the equilibrium solution are established. Asymptotic nature of solutions in the absence of an equilibrium solution is also discussed.

In this article, we propose to consider a problem of bioinformatics relating to the spread of en epidemics. A mathematical model is proposed and qualitative issues related to the spread of epidemic is highlighted. A neural network architecture has been proposed and utilized to simulate a few relevant simulations.

A chemostat model with distributed time delays in both nutrient recycling and biotic species growth is considered. A more general class of uptake functions, which includes all continuous functions having a saturation effect is studied. Existence and uniqueness of equilibrium solutions under fairly general circumstances are established. Several easi...

In this article, a model describing the activation dynamics of bidirectional associative memory (BAM) neural networks involving transmission delays was considered. The concept of BAM networks employed in this work is improved and it includes the earlier notions known in the literature and is applied to a wider class of networks. Further, we introdu...

The local asymptotic stability of equilibria is studied for a class of second-order differential equations with time lags using simple analytical criteria. Conditions for no change in stability are obtained. The presence of Hopf bifurcation is examined and the stability of bifurcating periodic solutions is discussed. Applications are mentioned from...

A mathematical model describing the dynamical interactions of bidirectional associative memory networks, incorporating among other things, propagational time delays, have been proposed in this paper. The existence and stability characteristics of the equilibrium patterns have been discussed. Three sets of easily verifiable sufficient conditions des...

The main focus of this paper is to consider a predator prey system model with a discrete delay in the prey birth dynamics and a distributed delay in the predator food conversion dynamics. Under standard hypotheses, the system is transformed into a three-dimensional system with discrete delay. The equilibria are analyzed for their stability properti...

A single-species model of population growth is considered, where the carrying capacity of the environment is time-dependent and asymptotically approaches a periodic function. Under reasonable hypotheses, it is shown that there exists a globally asymptotically stable solution of the model.

A system of two autonomous ordinary differential equations with two discrete time delays is considered, with a view to determining the stability of equilibria. Using the Nyquist criterion on the characteristic equation, estimates on the length of delays are given for which a system is stable in the absence of delays remains stable. Conditions are a...

Models of three-species food chains incorporating mutual interference among predators and time delays due to gestation are proposed. We consider the case that for such models an interior equilibrium exists. In the case that the equilibrium is stable with no delays, the length of delay is estimated for which stability continues to hold. Further, con...

The existence of coupled maximal and minimal quasi solutions of a system of second order periodic boundary value problems is discussed when the right hand side possesses a mixed monotone property.

Consider the second order nonlinear equation where, r, p, f ε C ([ a , + ∞), R ), R = (–∞, +∞) with r > 0 and λ > 0 is the quotient of odd integers. One of the prototypes of this class of equations is the generalized Thomas-Fermi of Emden-Fowler equation

This paper is concerned with nonoscillation criteria and asymptotic behaviour for forced second order nonlinear differential equations. These results improve and include several well-known results.

This paper is concerned with the existence, uniqueness and boundedness of random solutions of a random nonlinear mixed integral equation of Volterra-Fredholm type. The main tools for the study are the theory of admissibility of integral operators and the theory of random contractors.

We present a Gause predator-prey model incorporating mutual interference among predators, a density-dependent predator death rate and a time lag due to gestation. It is well known that mutual interference is stabilizing, whereas time delays are destabilizing. We show that in combining the two, a long time-lag usually, but not always, destabilizes t...

The Gause predator-prey model (Freedman, 1980, Chapter 4) separates the specific growth rate of the prey from the predator functional response. Hassell (1971) and Rogers and Hassell (1974) introduced the notion of mutual interference of predators searching for prey. This idea was incorporated into the Gause predator-prey model in Freedman (1979). I...

This paper is concerned with the questions of existence, uniqueness, and stability of wide sense and random solutions of nonlinear stochastic integral equations of mixed type. The main tools are the theory of admissibility and the fixed-point theorems. The results in this paper improve some earlier works qualitatively by reducing the hypotheses. Al...

Integral inequalities involving Stieltjes integrals developed in this paper are generalizations of Gronwall-Bellman inequalities.

In this paper we consider a nonlinear differential-integral equation which arises in the problems of ecology and study the questions of convergent solutions and asymptotic equivalence of the solutions.

The last 3 references in the author's note [1] should read as follows: [4] V. Sree Hari Rao, “On boundedness of impulsively perturbed systems”, Bull. Austral. Math. Soc. 18 (1978), 237–242. [5] V. Sree Hari Rao, “Asymptotically self invariant sets and stability of measure differential equations“, Nonlinear Anal., Theory, Methods Appl. 2 (1978), 483...