Archana, Kishore; Dr.Sarita,Bhat G(Cochin University of Science and Technology, March , 2007)
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Abstract:
The temperate, filamentous phage ФMV -5 isolated from Mangalavanam
mangrove of Kochi, using the environmental strain of Vibrio sp. MV-5 shares
many similar properties with other marine phage isolates, while also remaining
unique. The study has revealed that the interaction of temperate phages and the
microbial population in the marine environment may contribute significantly to
microbial genetic diversity and composition by conversion and transduction and
which requires greater study.Prophages contribute a substantial share of the mobile DNA of their
bacterial hosts and seem to influence the short-term evolution of pathogenic
bacteria. Automated methods for systematic investigation of prophages and other
mobile DNA elements in the available bacterial genome sequences will be
necessary to understand their role in bacterial genome evolution. In the past,
phages were mainly investigated as the simplest model systems in molecular
biology. Now it is increasingly realized that phage research will be instrumental in
the understanding of bacterial abundance in the environment. One can predict that
phage research will impact diverse areas such as geochemistry and medicine.
Success will largely depend on integrative multidisciplinary approaches in this
field. Clearly, further studies are required to understand how vibriophages interact
with Vibrios to promote this organism's acquisition of the critical genes which alter
its virulence or adaptation to its environmental niche.It is evident from this study and comparison with those reports cited above
that vibriophage ФMV-5 is a previously unreported bacteriophage. It is
recommended that the minimum requirement for reporting a new phage should be
novel morphological markers and a description of host range, both of which have
been achieved in this study.
Description:
Department of Biotechnology,
Cochin University of Science and Technology
Priyaja, P; Dr.Rosamma,Philip; Dr.Bright Singh,I S(Cochin University of Science and Technology, January , 2012)
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Abstract:
Pyocyanin is a versatile and multifunctional phenazine, widely used as a bio-control agent. Besides its toxicity in higher concentration, it has been applied as bio-control agents against many pathogens including the Vibrio spp. in aquaculture systems. The exact mechanism of
the production of pyocyanin in Pseudomonas aeruginosa is well known, but the
genetic modification of pyocyanin biosynthetic pathways in P. aeruginosa is not yet
experimented to improve the yield of pyocyanin production. In this context, one of
the aims of this work was to improve the yield of pyocyanin production in P.
aeruginosa by way of increasing the copy number of pyocyanin pathway genes and
their over expression. The specific aims of this work encompasses firstly, the
identification of probiotic effect of P. aeruginosa isolated from various ecological
niches, the overexpression of pyocyanin biosynthetic genes, development of an
appropriate downstream process for large scale production of pyocyanin and its
application in aquaculture industries. In addition, this work intends to examine the
toxicity of pyocyanin on various developmental stages of tiger shrimp (Penaeus
monodon), Artemia nauplii, microbial consortia of nitrifying bioreactors (Packed Bed
Bioreactor, PBBR and Stringed Bed Suspended Bioreactor, SBSBR) and in vitro cell
culture systems from invertebrates and vertebrates. The present study was undertaken
with a vision to manage the pathogenic vibrios in aquaculture through eco-friendly
and sustainable management strategies with the following objectives:
Identification of Pseudomonas isolated from various ecological niches and its antagonism to pathogenic vibrios in aquaculture.,Saline dependent production of pyocyanin in Pseudomonas aeruginosa originated from different ecological niches and their selective application in aquaculture,Cloning and overexpression of Phz genes encoding phenazine biosynthetic pathway for the enhanced production of pyocyanin in Pseudomonas aeruginosa MCCB117,Development of an appropriate downstream process for large scale production of pyocyanin from PA-pUCP-Phz++; Structural elucidation and functional analysis of the purified compoundToxicity of pyocyanin on various biological systems.
Description:
Department of Marine Biology,
Microbiology and Biochemistry
School of Marine Sciences, Cochin University of Science and
Technology
Premnath, R; Dr.Madhu, G(Cochin University of Science & Technology, November , 2011)
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Abstract:
Data centre is a centralized repository,either physical or virtual,for the storage,management and dissemination of data and information organized around a particular body and nerve centre of the present IT revolution.Data centre are expected to serve uniinterruptedly round the year enabling them to perform their functions,it consumes enormous energy in the present scenario.Tremendous growth in the demand from IT Industry made it customary to develop newer technologies for the better operation of data centre.Energy conservation activities in data centre mainly concentrate on the air conditioning system since it is the major mechanical sub-system which consumes considerable share of the total power consumption of the data centre.The data centre energy matrix is best represented by power utilization efficiency(PUE),which is defined as the ratio of the total facility power to the IT equipment power.Its value will be greater than one and a large value of PUE indicates that the sub-systems draw more power from the facility and the performance of the data will be poor from the stand point of energy conservation. PUE values of 1.4 to 1.6 are acievable by proper design and management techniques.Optimizing the air conditioning systems brings enormous opportunity in bringing down the PUE value.The air conditioning system can be optimized by two approaches namely,thermal management and air flow management.thermal management systems are now introduced by some companies but they are highly sophisticated and costly and do not catch much attention in the thumb rules.
Description:
Division of Safety and Fire Engineering,School of Engineering,Cochin University of Science and Technology
Premnath, R; Dr.Madhu, G(Cochin University Of Science And Technology, November , 2011)
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Abstract:
In the present study the effect of hot air recirculation is studied with suitable
assumptions. It identifies that, the pressure drop across the tile is a dominant
parameter which governs the recirculation. The rack suction pressure of the
hardware along with the pressure drop across the tile determines the point of
recirculation in the cold aisle. The positioning of hardware in the racks play an
important role in controlling the recirculation point. The present study is thus
helpful in the design of data centre air flow, based on the theory of jets. The air
flow can be modelled both quantitatively and qualitatively based on the results
Description:
Division Of Safety And Fire Engineering
School Of Engineering
Cochin University Of Science And Technology
Premnath, R; Dr.Madhu, G(Cochin University of Science and Technology, November , 2011)
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Abstract:
This work identifies the importance of plenum pressure on the performance
of the data centre. The present methodology followed in the industry considers the
pressure drop across the tile as a dependant variable, but it is shown in this work
that this is the only one independent variable that is responsible for the entire flow
dynamics in the data centre, and any design or assessment procedure must consider
the pressure difference across the tile as the primary independent variable. This
concept is further explained by the studies on the effect of dampers on the flow
characteristics. The dampers have found to introduce an additional pressure drop
there by reducing the effective pressure drop across the tile. The effect of damper is
to change the flow both in quantitative and qualitative aspects. But the effect of
damper on the flow in the quantitative aspect is only considered while using the
damper as an aid for capacity control. Results from the present study suggest that
the use of dampers must be avoided in data centre and well designed tiles which
give required flow rates must be used in the appropriate locations.
In the present study the effect of hot air recirculation is studied with suitable
assumptions. It identifies that, the pressure drop across the tile is a dominant
parameter which governs the recirculation. The rack suction pressure of the
hardware along with the pressure drop across the tile determines the point of
recirculation in the cold aisle. The positioning of hardware in the racks play an
important role in controlling the recirculation point. The present study is thus
helpful in the design of data centre air flow, based on the theory of jets. The air
flow can be modelled both quantitatively and qualitatively based on the results.
Description:
Division of Safety and Fire Engineering,
School of Engineering, Cochin University of Science and Technology
Nirmala, Thampuran; Dr.Gopakumar, K(Cochin University of Science and Technology, January 1, 1987)
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Abstract:
The thesis is mainly concerned with the study of
the bacteriology of freezing of mackerel(Rastrelliger
kanaggrta)and prawn (Metgpggaeus ddbsoni)
The thesis in four sections describes the salient
features of the observations and inferences on the
bacteriology of freezing of fishes and prawns. This
includes the evaluation of methodology for the optimum
recovery of bacteria, bacteriology of the newly caught
fish and prawn, the effect of freezing temperatures on
the survival of selected species of isolates from fish
and prawn and the bacteriology of freezing, frozen
storage and thawing of prawn/fish emphasizing the effect
contributed by each.
Description:
School of marine Science, Cochin University of Science and Technology
Sreenivasan, C; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, August 16, 2012)
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Abstract:
The objective of the study of \Queueing models with vacations and working
vacations" was two fold; to minimize the server idle time and improve the
e ciency of the service system. Keeping this in mind we considered queueing
models in di erent set up in this thesis.
Chapter 1 introduced the concepts and techniques used in the thesis and
also provided a summary of the work done. In chapter 2 we considered an
M=M=2 queueing model, where one of the two heterogeneous servers takes
multiple vacations. We studied the performance of the system with the help
of busy period analysis and computation of mean waiting time of a customer
in the stationary regime. Conditional stochastic decomposition of queue
length was derived. To improve the e ciency of this system we came up
with a modi ed model in chapter 3. In this model the vacationing server
attends the customers, during vacation at a slower service rate. Chapter
4 analyzed a working vacation queueing model in a more general set up.
The introduction of N policy makes this MAP=PH=1 model di erent from
all working vacation models available in the literature. A detailed analysis
of performance of the model was provided with the help of computation of
measures such as mean waiting time of a customer who gets service in normal
mode and vacation mode.
Description:
Department of Mathematics, Cochin University of Science and Technology
Sreenivasan, C; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, June 16, 2012)
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Abstract:
The thesis entitled “Queueing Models with Vacations and Working Vacations" consists of seven chapters including the introductory chapter. In chapters 2 to 7 we analyze different queueing models highlighting the role played by vacations and working vacations. The duration of vacation is exponentially distributed in all these models and multiple vacation policy is followed.In chapter 2 we discuss an M/M/2 queueing system with heterogeneous servers, one of which is always available while the other goes on vacation in the absence of customers waiting for service. Conditional stochastic decomposition of queue length is derived. An illustrative example is provided to study the effect of the input parameters on the system performance measures. Chapter 3 considers a similar setup as chapter 2. The model is analyzed in essentially the same way as in chapter 2 and a numerical example is provided to bring out the qualitative nature of the model. The MAP is a tractable class of point process which is in general nonrenewal. In spite of its versatility it is highly tractable as well. Phase type distributions are ideally suited for applying matrix analytic methods. In all the remaining chapters we assume the arrival process to be MAP and service process to be phase type. In chapter 4 we consider a MAP/PH/1 queue with working vacations. At a departure epoch, the server finding the system empty, takes a vacation. A customer arriving during a vacation will be served but at a lower rate.Chapter 5 discusses a MAP/PH/1 retrial queueing system with working vacations.In chapter 6 the setup of the model is similar to that of chapter 5. The signicant dierence in this model is that there is a nite buer for arrivals.Chapter 7 considers an MMAP(2)/PH/1 queueing model with a nite retrial group
Description:
Department of
Mathematics, Cochin University of Science and Technology.
Jacob,K Daniel; Dr.Krishnamoorthy,A(Cochin University Of Science And Technology, 1985)
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Abstract:
In this thesis we study the effect of rest periods
in queueing systems without exhaustive service and inventory
systems with rest to the server. Most of the works in the
vacation models deal with exhaustive service. Recently
some results have appeared for the systems without exhaustive
service.
Description:
Department Of‘ Mathematics And Statistics,Cochin University Of Science And Technology
Varghese,Jacob; Dr.Krishnamoorthy,A; Dr.Narayanan Namboothiri, M N(Cochin University of Science and Technology, June 16, 2012)
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Abstract:
In this thesis we have introduced and studied the notion of self interruption of service by customers. Service interruption in queueing systems have been extensively discussed in literature (see, Krishnamoorthy, Pramod and Chakravarthy [38]) for the most recent survey. So far all work reported deal with cases in which service interruptions are generated by sources other than customers. However, there are situations where interruptions are due to the customers rather than the system. Such situations
are especially arise at doctors clinic, banks, reservation counter etc. Our attempt is to quantify a few of such problems. Systematically we have proceed from single server queue (in Chapter 2) to multi-server
queues (Chapter 3). In Chapte 4, we have studied a very general multiserver queueing model with service interruption and protection of service phases. We also introduced customer interruption in a retrial setup (in Chapter 5). All models (from Chapter 2 to Chapter 4) that were analyzed involve 'non-preemptive priority' for interrupted customers where as in the model discussed in Chapter 5 interruption of service by customers is not encouraged. So the interrupted customers cannot access the server as long as there are primary customers in the system. In Chapter 5 we have obtained an explicit expression for the stability condition of the system. In all models analyzed in this thesis, we have assumed that no more than one interruption is allowed for a customer while in service. Since the models are not analytically tractable, a large number of numerical illustrations were given in each chapter it illustrate the working of the systems.
We can extend the models discussed in this thesis to several directions. For example some of the models can be analyzed with both server induced and customer induced interruptions the results for which are not available till date. Another possible extension of work is to the case where there is
no bound on the number of interruptions a customer is permitted to have before service completion. More complex is the case where a customer is permitted to have a nite number (K ≥ 2) of We can extend the models discussed in this thesis to several directions.
Description:
Department of
Mathematics, Cochin University of Science and Technology.
Jaya, S; Dr. B Lakshmi(Cochin University of Science and Technology, August 3, 2015)
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Abstract:
In many situations probability models are more realistic than deterministic
models. Several phenomena occurring in physics are studied as random
phenomena changing with time and space. Stochastic processes originated
from the needs of physicists.Let X(t) be a random variable where t is a parameter assuming values
from the set T. Then the collection of random variables {X(t), t ∈ T} is
called a stochastic process. We denote the state of the process at time t
by X(t) and the collection of all possible values X(t) can assume, is called state space
Viswanath C Narayanan; Krishnamoorthy,A(Department of Mathematics, 2005)
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Abstract:
Application of Queueing theory in areas like Computer networking, ATM facilities, Telecommunications and to many other numerous situation made people study Queueing models extensively and it has become an ever expanding branch of applied probability. The thesis discusses Reliability of a ‘k-out-of-n system’ where the server also attends external customers when there are no failed components (main customers), under a retrial policy, which can be explained in detail. It explains the reliability of a ‘K-out-of-n-system’ where the server also attends external customers and studies a multi-server infinite capacity Queueing system where each customer arrives as ordinary but can generate into priority customer which waiting in the queue. The study gives details on a finite capacity multi-server queueing system with self-generation of priority customers and also on a single server infinite capacity retrial Queue where the customer in the orbit can generate into a priority customer and leaves the system if the server is already busy with a priority generated customer; else he is taken for service immediately. Arrival process is according to a MAP and service times follow MSP.