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Applied Mathematics 2017年第8期8卷 1211-1225页

作者： tirupathi rao padi Chiranjeevi Gudala Department of Statistics Pondicherry University Puducherry India

In this paper, a bivariate stochastic process with Poisson postulates has been considered to model the incomings, outgoings and mutual transfers of investments between and within the portfolios during an epoch of time “t”. Stochastic differential equations were obtained from the simple differential difference equations during the epoch of time “Δt”. The notion of bivariate linear birth, death and migration process has been utilized for measuring various statistical characteristics among the investments of Long and Short terms. All possible fluctuations in the investment flow have been considered to explore more meaningful assumptions with contemporary marketing environments. Mathematical relations for proposed statistical measures such as average sizes and variances of short term and long-term investments along with the correlation coefficient between them are derived after obtaining the related differential equations. Numerical illustrations were provided for better understanding of the developed models with practitioner’s point of view.

关键词： Stochastic Modelling Portfolio Diversification Difference-Differential Equations

Evaluation of Manager’s Performance through Stochastic Modelling

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Open Journal of Statistics 2013年第1期3卷 47-53页

作者： P. tirupathi rao Department of Statistics Pondicherry University Puducherry India

Decision making is one of the important activities of the managerial problems. Scientific methodology for quantitative techniques is an essential tool in the contemporary decision making protocols. In this paper an attempt is made to develop a stochastic model on manager’s performance appraisal. Managerial choice among the available options for decision making is formulated to obtain the stochastic process, to derive the model and to obtain statistical measures. Numerical illustrations are provided for understanding the managerial performance and its evaluation. This study is useful to assess the abilities of an employee by his/her employer. Development of Desktop automations to this study will open a wide spectrum of dynamic Decision Support Systems.

关键词： Stochastic Modelling Manager’s Performance Management Decision Making

Anti-microbial principles of selected remedial plants from Southern India

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Asian Pacific Journal of Tropical Biomedicine 2011年第4期1卷 298-305页

作者： tirupathi rao G Suresh Babu K J Ujwal Kumar Sujana P A Veerabhadr raoa Sreedhar AS Centre for Cellular and Molecular Biology Hyderabad 500 007India Division of Organic Chemistry-I Natural Products LaboratoryIndian Institute of Chemical TechnologyHyderabad-500 607India

Objective:To examine the anti-bacterial activity of leaf extracts of Morus alba L.(Moraceae)and Piper betel L.(Piperaceae),and seed extracts of Bombax ceiba L.(Borabacaceae).Methods:We have partially purified plant extracts by solvent extraction method,and evaluated the effect of individual fractions on bacterial growth using Escherichia coli(***),Pseudomonas aeruginosa(***) and Staphylococcus aureus(***) bacterial ***:Compared with Morus and Bombax fractions,Piper fractions showed significant growth inhibition on all the three types of bacteria *** EtOAc-hexane fractions of Piper leaves exhibited significant antibacterial activity with minimum inhibitory concentrations(MIC) of 50 μg/mL culture against both gram-positive and gram-negative *** EtOAc-fractions Ⅰ,Ⅱ,and Ⅳ inhibited bacterial colony formation on soft agar in addition to growth inhibition.A combination treatment of piper fractions with ampicillin resulted in significant growth inhibition in *** and ***,and combination with anticancer drug geldanamycin(2 μg/mL) showed selective growth inhibition against *** and *** major compounds,i.e.,eugenol,3-hexene-ol and stigmasterol,were primarily identified from Piper betel leaf *** the individual compounds,eugenol treatment showed improved growth inhibition compared with stigmasterol and ***:We are reporting potential anti-bacterial compounds from Piper betel against both gram-positive and gram-negative bacteria either alone or in combination with drug treatment.

关键词： Piper betel Anti-microbial activity Escherichia coli Pseudomonas aeruginosa Staphylococcus aureus Morus alba Bombax ceiba Minimum inhibitory concentration Growth inhibition

Manpower Systems Operating under Heavy and Light Tailed Inter-Exit Time Distributions

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Applied Mathematics 2014年第2期5卷 285-291页

作者： R. Sivasamy P. tirupathi rao K. Thaga Department of Statistics Pondicherry University Puducherry India Statistics Department University of Botswana Gaborone Botswana

This paper considers a Manpower system where “exits” of employed personnel produce some wastage or loss. This system monitors these wastages over the sequence of exit epochs {t0 = 0 and tk;k = 1, 2,…} that form a recurrent process and admit recruitment when the cumulative loss of man hours crosses a threshold level Y, which is also called the breakdown level. It is assumed that the inter-exit times Tk = tk-1 - tk, k = 1, 2,… are independent and identically distributed random variables with a common cumulative distribution function (CDF) B(t) = P(Tk t) which has a tail 1 – B(t) behaving like t-v with 1 v as t → ∞. The amounts {Xk} of wastages incurred during these inter-exit times {Tk} are independent and identically distributed random variables with CDF P(Xk X) = G(x) and Y is distributed, independently of {Xk} and {tk}, as an exponentiated exponential law with CDF H(y) = P(Y y) = (1 - e-λy)n. The mean waiting time to break down of the system has been obtained assuming B(t) to be heavy tailed and as well as light tailed. For the exponential case of G(x), a comparative study has also been made between heavy tailed mean waiting time to break down and light tailed mean waiting time to break down values. The recruitment policy operating under the heavy tailed case is shown to be more economical in all types of manpower systems.

关键词： Manpower System Recruitment Policy Inter-Exit Time Wastage Waiting Time to Breakdown Heavy Tailed Inter-Exit Time Distribution and Light Tailed Distribution

Fingerprint Recognition on Various Authentication Sensors

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Journal of Electronic Science and Technology 2014年第1期12卷 134-138页

作者： A.tirupathi rao N.Pattabhi Ramaiah C.Krishna Mohan Department of Computer Science and Engineering Indian Institute of Technology

Fingerprint is a very popular and an ancient biometric technology to uniquely identify a person. In this paper, a fingerprint matcher is proposed which uses the global and local adaptive binarization and global minutia features. The fingerprint data is collected using three different authentication devices based on optical sensors. The experimental results are compared with the National Institute of Standards and Technology （NIST） Bozorth algorithm and various authentication fingerprint sensors. The accuracy of the proposed algorithm has been improved significantly compared with that of the NIST Bozorth algorithm.

关键词： -Authentication sensors binarization,Bozorth algorithm fingerprints NIST.

Numerical Modeling of Non-Similar Mixed Convection Heat Transfer over a Stretching Surface with Slip Conditions

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World Journal of Mechanics 2015年第6期5卷 117-128页

作者： A. Subba rao V. R. Prasad N. Nagendra K. V. N. Murthy N. Bhaskar Reddy O. Anwar Beg Department of Mathematics Madanapalle Institute of Technology and Science Madanapalle India Department of Mathematics Sri Venkateswara University Tirupathi India Gort Engovation Research (Propulsion and Biomechanics) Bradford UK

In this paper, the heat transfer effect on the steady boundary layer flow of a Casson fluid past a stretching surface in the presence of slip conditions was analyzed. The stretching surface is maintained at a constant temperature. The boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller-box finite difference scheme. The resulting equations are solved numerically by using the Kellerbox finite-difference method, and the expressions for velocity and temperature are obtained. They satisfy all imposed initial and boundary conditions and reduce to some well-known solutions for non-Newtonian fluids. Numerical results for velocity, temperature, skin friction and Nusselt number are shown in various graphs and discussed for embedded flow parameters. It is found that both velocity and temperature decrease with an increase of the Casson fluid parameter.

关键词： Stretching Surface Non-Newtonian Fluid Slip Condition Keller-Box Numerical Method Heat Transfer Skin Friction Coefficient