Jose, K P; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, December 28, 2006)
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Abstract:
This thesis Entitled Stochastic modelling and analysis.This thesis is divided into six chapters including this introductory chapter. In second chapter, we consider an (s,S) inventory model with service, reneging of customers and finite shortage of items.In the third chapter, we consider an (s,S) inventoiy system with retrial of customers. Arrival of customers forms a Poisson process with rate. When the inventory level depletes to s due to demands, an order for replenishment is placed.In Chapter 4, we analyze and compare three (s,S) inventory systems with positive service time and retrial of customers. In all these systems, arrivals of customers form a Poisson process and service times are exponentially distributed. In chapter 5, we analyze and compare three production inventory systems with positive service time and retrial of customers. In all these systems, arrivals of customers form a Poisson process and service times are exponentially distributed.In chapter 6, we consider a PH /PH /l inventory model with reneging of customers and finite shortage of items.
Description:
Department of Mathematics, Cochin University of Science
and Technology
Lakshmy, B; Dr.Krishnamoorthy,A(Cochin University of Science And Technology, February , 1991)
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Abstract:
This thesis analyses certain problems in Inventories
and Queues. There are many situations in real-life where we
encounter models as described in this thesis. It analyses
in depth various models which can be applied to production,
storag¢, telephone traffic, road traffic, economics, business
administration, serving of customers, operations of particle
counters and others. Certain models described here is not a
complete representation of the true situation in all its
complexity, but a simplified version amenable to analysis.
While discussing the models, we show how a dependence structure can be suitably introduced in some problems of Inventories and Queues. Continuous review, single commodity inventory systems with Markov dependence structure introduced in the demand quantities, replenishment quantities and reordering levels are considered separately. Lead time is assumed to be zero in these models. An inventory model involving random lead
time is also considered (Chapter-4). Further finite capacity
single server queueing systems with single/bulk arrival,
single/bulk services are also discussed. In some models the
server is assumed to go on vacation (Chapters 7 and 8). In
chapters 5 and 6 a sort of dependence is introduced in the
service pattern in some queuing models.
Description:
Department of mathematics & statistics, Cochin University of Science And Technology
Madhusoodanan,T P; Dr.Krishnamoorthy,A(Cochin University of Science And Technology, 1988)
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Abstract:
The objective of this thesis is to study the time dependent behaviour of some complex queueing and inventory models. It contains a detailed analysis of the basic stochastic processes underlying these models. In the theory of queues, analysis of time dependent behaviour is an area.very little developed compared to steady state theory. Tine dependence seems certainly worth studying from an application point of view but unfortunately, the analytic difficulties are considerable.
Glosod form solutions are complicated even for such simple models as M/M /1. Outside M/>M/1, time dependent solutions have been found only in special cases and involve most often double transforms which provide very little insight into the behaviour of the queueing systems themselves. In inventory theory also There is not much results available giving the time
dependent solution of the system size probabilities. Our emphasis is on explicit results free from all types of transforms and the method used may be of special interest to a wide variety of problems having regenerative structure.
Description:
Department of mathematics, Cochin University of Science And Technology
Ajith,Joseph K; Dr. Balchand, A N(Cochin University of Science and Technology, December , 1996)
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Abstract:
The dynamics and associated stability analysis of tidal inlets situated on the southwest coast of India, namely Andhakaranazhi (90 45 J OO JJN and 760 17 J 29 JJ E) and the other at
Cochin harbour inlet (90 58 1 04 J1N and 760 14 1 50 1J E) have beenconducted. A detailed study on the inlet regime of Cochin barmouth (permanent in nature) was attempted so as to elucidate information on: (a) channel characteristics (b) tidal hydraulics and (c) stability of the inlet. In this
connection, a naturally occurring seasonal sandbar formation at Andhakaranazhi, near Sherthallay, about 20 km south of Cochin inlet, was also chosen as a site ofstudy brought out conclusively the dynamical study. The aspects of ( 1) tidal influx/out flux (2) channel morphology (3) sedimentation regime and (4) stability and factors related
to stability of these locations. The above aspects are supported by suitable mathematical formulations to describe the associated coastal processes, wherever applicable
Description:
School of marine science, Department of Physical Oceanography, Cochin University of
Science and Technology
Vinu, Thomas; Dr.Mathew, K T(Cochin University of Science & Technology, September , 2008)
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Abstract:
Electromagnetic tomography has been applied to problems in
nondestructive evolution, ground-penetrating radar, synthetic aperture
radar, target identification, electrical well logging, medical imaging
etc. The problem of electromagnetic tomography involves the
estimation of cross sectional distribution dielectric permittivity,
conductivity etc based on measurement of the scattered fields. The
inverse scattering problem of electromagnetic imaging is highly non
linear and ill posed, and is liable to get trapped in local minima. The
iterative solution techniques employed for computing the inverse
scattering problem of electromagnetic imaging are highly computation
intensive. Thus the solution to electromagnetic imaging problem is
beset with convergence and computational issues. The attempt of this
thesis is to develop methods suitable for improving the convergence
and reduce the total computations for tomographic imaging of two
dimensional dielectric cylinders illuminated by TM polarized waves,
where the scattering problem is defmed using scalar equations. A multi
resolution frequency hopping approach was proposed as opposed to
the conventional frequency hopping approach employed to image large
inhomogeneous scatterers. The strategy was tested on both synthetic
and experimental data and gave results that were better localized and
also accelerated the iterative procedure employed for the imaging. A
Degree of Symmetry formulation was introduced to locate the scatterer
in the investigation domain when the scatterer cross section was
circular. The investigation domain could thus be reduced which
reduced the degrees of freedom of the inverse scattering process. Thus
the entire measured scattered data was available for the optimization of
fewer numbers of pixels. This resulted in better and more robust reconstructions of the scatterer cross sectional profile. The Degree of
Symmetry formulation could also be applied to the practical problem
of limited angle tomography, as in the case of a buried pipeline, where
the ill posedness is much larger. The formulation was also tested
using experimental data generated from an experimental setup that was
designed. The experimental results confirmed the practical
applicability of the formulation.
Description:
Department of Electronics,
Cochin University of Science and Technology
Sathiyamoorthy,V; Dr.Mohan Kumar, K(Department of Atmospheric Sciences, 2001)
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Abstract:
The aim of the present study is to understand the biennial scale stratosphere-troposphere interactions over India, and synoptic to interannual timescale meridional stratosphere-troposhere exchanges caused by upper tropospheric/lower stratospheric longwaves using NCEP/NCAR reanalysis data and satellite measured total ozone data. The biennial timescale interaction between lower stratosphere and troposphere over Thumba is analysed using high-resolution radiosonde data. The results suggest that TBO and QBO are two different phenomena with nearly biennial periodicity. Interannual timescale meridional stratosphere-troposphere exchanges caused by the newly documented Asia Pacific Wave (APW) were analysed using ozone as tracer of atmospheric motion. Synoptic timescale meridional stratosphere-troposhere exchanges caused by subtropical upper tropospheric long waves over Asia were studied using global total ozone measurements from TOMS. This research work can be extended to study the influence of decadal scale epochal nature in Indian summer monsoon activity on the APW generated total ozone anomalies around the globe and the trend estimates in total ozone
Manoj, G Tharian; Dr C.G Nandakumar(Cochin University of Science and Technology, March 16, 2015)
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Abstract:
Hat Stiffened Plates are used in composite ships and are gaining popularity in metallic ship
construction due to its high strength-to-weight ratio. Light weight structures will result in greater
payload, higher speeds, reduced fuel consumption and environmental emissions. Numerical
Investigations have been carried out using the commercial Finite Element software ANSYS 12 to
substantiate the high strength-to-weight ratio of Hat Stiffened Plates over other open section
stiffeners which are commonly used in ship building.
Analysis of stiffened plate has always been a matter of concern for the structural engineers
since it has been rather difficult to quantify the actual load sharing between stiffeners and
plating. Finite Element Method has been accepted as an efficient tool for the analysis of stiffened
plated structure. Best results using the Finite Element Method for the analysis of thin plated
structures are obtained when both the stiffeners and the plate are modeled using thin plate
elements having six degrees of freedom per node. However, one serious problem encountered
with this design and analysis process is that the generation of the finite element models for a
complex configuration is time consuming and laborious. In order to overcome these difficulties
two different methods viz., Orthotropic Plate Model and Superelement for Hat Stiffened Plate
have been suggested in the present work.
In the Orthotropic Plate Model geometric orthotropy is converted to material orthotropy
i.e., the stiffeners are smeared and they vanish from the field of analysis and the structure can be
analysed using any commercial Finite Element software which has orthotropic elements in its
element library. The Orthotropic Plate Model developed has predicted deflection, stress and
linear buckling load with sufficiently good accuracy in the case of all four edges simply
supported boundary condition. Whereas, in the case of two edges fixed and other two edges
simply supported boundary condition even though the stress has been predicted with good
accuracy there has been large variation in the deflection predicted. This variation in the
deflection predicted is because, for the Orthotropic Plate Model the rigidity is uniform throughout the plate whereas in the actual Hat Stiffened Plate the rigidity along the line of
attachment of the stiffeners to the plate is large as compared to the unsupported portion of the
plate.
The Superelement technique is a method of treating a portion of the structure as if it were a
single element even though it is made up of many individual elements. The Superelement has
predicted the deflection and in-plane stress of Hat Stiffened Plate with sufficiently good accuracy
for different boundary conditions. Formulation of Superelement for composite Hat Stiffened
Plate has also been presented in the thesis. The capability of Orthotropic Plate Model and
Superelement to handle typical boundary conditions and characteristic loads in a ship structure
has been demonstrated through numerical investigations.
Sarada,S; Sankaranarayanan,K C(School of Management studies, Faculty of Social sciences, 2004)
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Abstract:
The focus of this study is the stress of women entrepreneurs.As stress is associated with constraints and demands, and as a set of emerging conditions seem to affect the quality of life of women, it is more than just an occasional need to enquire in to the possibilities of promoting entrepreneurship by empowering women.As women entrepreneurs are increasingly involved in inherently complicated activities of improving their enterprise functioning ,it would be appropriate for women entrepreneurs to focus on transformational coping interventions.The study is limited to women entrepreneurs in the tiny sector.Women entrepreneurs registered in the Distric Industries ( DIC) and in the Kerala State Women’s Industries Association (KSWIA) are only selected for the study.It gaves a detailed description about empowerment of women.The social , economic ,political,ecological,and psychological importance of the study are detailed.It explains the family related stress, and the contextual system.This study is suggested on beliefs and values of women about their self-perception influencing gender bias, which contribute to stress and coping.This study is also needed about women’s believes and expectations about the probable effectiveness of various course of action and their ability to perform those actions.It is also neede for appraising coping potential of women and enhancing their stress base.It is important to research on stress and self-concept
Anupama Nair, P R; Dr.Mohammed Salih,K Y; Dr.Sujatha, C H(Cochin University Of Science And Technology, May , 2008)
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Abstract:
Poisoning by pesticides from agricultural fields is a serious water
pollution problem and its environmental long-term effect may result in the
incidence of poisoning of fish and other aquatic life forms (jyothi and
Narayan, 1999). Fishes like Heteropneustesfbssilis and C/arius batrac/nus are
especially prone to serious pesticide pollution as their habitat is mostly the
agriculture area. Though only few studies are conducted in this area, it can
be assessed from the local information that, population of such fish is on
the verge of vulnerability due to extensive use of pesticides. The knowledge
of sublethal effects of xenobiotic compounds on hematological parameters,
enzyme activities and metabolite concentrations is very important to
delineate the fish health status and provide a future understanding of
ecological impacts. These pesticides act by causing inhibition of
cholinesterase enzymes (ChE) by formation of enzyme inhibitor complex
(O'Brien, 1976) and damaging the nervous system. These effects may result
in metabolic disorders. Associated to cholinesterase activities, a study of
other enzymes such as phosphatases and aminotransferases close to
intermediary metabolite determination provides a wider view of
metabolism. Interest in toxicological aspects has grown in recent years and
research is now increasingly focused on mechanistic aspects of oxidative damage and cellular responses in biological system. The term ‘biomarker’ is
generally used in a broad sense to include almost any measurement
reflecting an interaction between a biological system and a potential hazard,
which may be chemical, physical or biological (WHO, 1993). As biomarker
stands for immediate responses, they are used as early warning signals of
biological effects caused by environmental pollutants.
The present work attempts to assess the toxicity of organophosphorus
insecticide monocrotophos on the experimental organism selected for this
study namely stinging catfish (Heteropneustesfossi/is) (Bloch), and to probe
into the stress responses of the organism
Description:
Department of Marine Biology, Microbiology and
Biochemistry, Cochin University of Science and Technology
Varughese,Philip; Prathapachandra Kurup, M R(Dept. of Applied Chemistry, July , 2004)
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Abstract:
The study deals with structural and spectral investigations of transition metal complexes of di-2-pyridyl ketone N(4),N(4)-disubstituted thiosemicarbazones. The main objective and scope of the work deals with di-2-pyridyl ketone N(4),N(4)-disubstituted thiosemicarbazones are quardridentate NNNS donor ligands. To chosen this ligand for study because, the ligands are prepared and characterized for the first time, since there are two pyridyl nitorgens, dimmers and polymers of complexes may result leading to interesting structural aspects. The work includes the preparation of the thiosemicarbzones and their structural and spectral studies, synthesis and spectral characterization of complexes of copper(II),,nickel(II),manganese(II), dioxovanadium(V),cobalt(III),zinc(II),cadmium(II) of the ligand HL, synthesis and spectral characterization of complexes of copper(II),manganese(II), of the ligand HL and the development of X-ray quality crystals and its X-ray diffraction studies. The structural characterization techniques are elemental analysis, conductivity measurements, magnetic measurements, electronic spectroscopy, H NMR spectroscopy, Infrared spectroscopy and X-ray crystallography.