| Abstract: | Timely detection of sudden change in dynamics that adversely affect the performance of systems and quality of products has great scientific relevance. This work focuses on effective detection of dynamical changes of real time signals from mechanical as well as biological systems using a fast and robust technique of permutation entropy (PE). The results are used in detecting chatter onset in machine turning and identifying vocal disorders from speech signal.Permutation Entropy is a nonlinear complexity measure which can efficiently distinguish regular and complex nature of any signal and extract information about the change in dynamics of the process by indicating sudden change in its value. Here we propose the use of permutation entropy (PE), to detect the dynamical changes in two non linear processes, turning under mechanical system and speech under biological system.Effectiveness of PE in detecting the change in dynamics in turning process from the time series generated with samples of audio and current signals is studied. Experiments are carried out on a lathe machine for sudden increase in depth of cut and continuous increase in depth of cut on mild steel work pieces keeping the speed and feed rate constant. The results are applied to detect chatter onset in machining. These results are verified using frequency spectra of the signals and the non linear measure, normalized coarse-grained information rate (NCIR).PE analysis is carried out to investigate the variation in surface texture caused by chatter on the machined work piece. Statistical parameter from the optical grey level intensity histogram of laser speckle pattern recorded using a charge coupled device (CCD) camera is used to generate the time series required for PE analysis. Standard optical roughness parameter is used to confirm the results.Application of PE in identifying the vocal disorders is studied from speech signal recorded using microphone. Here analysis is carried out using speech signals of subjects with different pathological conditions and normal subjects, and the results are used for identifying vocal disorders. Standard linear technique of FFT is used to substantiate thc results.The results of PE analysis in all three cases clearly indicate that this complexity measure is sensitive to change in regularity of a signal and hence can suitably be used for detection of dynamical changes in real world systems. This work establishes the application of the simple, inexpensive and fast algorithm of PE for the benefit of advanced manufacturing process as well as clinical diagnosis in vocal disorders. |
| Description: | Division Of Mechanical Engineering,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2813 |
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| Dyuthi-T0834.pdf | (3.827Mb) |
| Abstract: | Machine tool chatter is an unfavorable phenomenon during metal cutting, which results in heavy vibration of cutting tool. With increase in depth of cut, the cutting regime changes from chatter-free cutting to one with chatter. In this paper, we propose the use of permutation entropy (PE), a conceptually simple and computationally fast measurement to detect the onset of chatter from the time series using sound signal recorded with a unidirectional microphone. PE can efficiently distinguish the regular and complex nature of any signal and extract information about the dynamics of the process by indicating sudden change in its value. Under situations where the data sets are huge and there is no time for preprocessing and fine-tuning, PE can effectively detect dynamical changes of the system. This makes PE an ideal choice for online detection of chatter, which is not possible with other conventional nonlinear methods. In the present study, the variation of PE under two cutting conditions is analyzed. Abrupt variation in the value of PE with increase in depth of cut indicates the onset of chatter vibrations. The results are verified using frequency spectra of the signals and the nonlinear measure, normalized coarse-grained information rate (NCIR). |
| URI: | http://dyuthi.cusat.ac.in/purl/2598 |
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| Dyuthi-P0158.pdf | (263.3Kb) |
| Abstract: | The purpose of personal financial management is achievement of personal financial freedom. It is a stage where finance will not be a hindrance against the fulfilment ofthe financial objectives of persons. After counting individual values and preferences we arrive at a standard or normal financial behaviour. Even though individuals differ in their tastes and preferences, there are a very large amount of commonality among them. The financial manager should list out the various financial objectives ofthe family. Then he should make the best choice from among the various alternatives on a priority based system. In short personal finance is concerned with the way in which a person manages his income and expenditure to achieve his personal financial objectives. Thus a proper personal financial planning is essential in every family for attaining financial discipline in the family. The fall ofthejoint family system, the growing financial responsibilities of modern families, limited chance ofincreasing income, growing population, financial insecurity of the government employees, lack of financial freedom, lack of proper personal financial practice and its awareness, the growing suicide rate on account offinancial crisis etc.,make the study a necessity |
| Description: | School of Management Studies,Department of Commerce, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3378 |
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| Dyuthi-T1355.pdf | (5.232Mb) |
| Abstract: | The study is about the Gulf-returned Keralites and their personal financial planning during the Gulf-period. The researcher has examined the nature of their income, expenditure, savings and investments during the Gulf-period and after their return. Even though the Gulf-returned Keralites had remitted huge amounts to Kerala, it appears that the majority of them are struggling hard to make both ends meet. The sample consists of 318 Gulf-returned Keralites selected by employing stratified random sampling technique, from 5 districts. After a pilot study, the data was collected through personal interviews using a structured schedule. In order to find out whether the respondents had personal financial planning during the Gulf-period, the researcher has evaluated 15 elements of personal financeusing a five-point-scale rating technique. The hypotheses were tested using correlation, t-test, chi-square and ANOVA, through SPSS. |
| Description: | School of Management Studies, Cochin University of Science and Technology. |
| URI: | http://dyuthi.cusat.ac.in/purl/3356 |
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| Dyuthi-T1333.pdf | (5.368Mb) |
| Abstract: | A study on the personnel management practices in the co+operative sector in the Kerala State is carried out during the years 1989-91, with the overall objective of assessing the extent of application of modern personnel management concepts in the cooperative organizations in the Kerala State. The specific objectives of the study are to assess the effectiveness of the various personnel management practices followed in the cooperative sector, to analyse the nature and extent of compensating the employees in co—operatives, to measure the level of job satisfaction derived by the employees, to evaluate the industrial relations existing in the co-operative organizations and to suggest, if found necessary, ways and means of toning up the personnel management practices followed in the co-operative sector in Kerala |
| Description: | School of Management Studies, Cochin University of Science and Technology, |
| URI: | http://dyuthi.cusat.ac.in/purl/3216 |
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| Dyuthi-T1190.pdf | (3.416Mb) |
| Abstract: | The thesis entitled Personnel Management Practices in the Kerala-Based Scheduled Commercial Banks. Personnel management function is of cardinal importance, requiring a sophisticated and scientific approach. In a labour-intensive, service industry like banking. Productivity and ultimate profitability of the entire organization depend considerably on the effectiveness with which personnel management function is executed; and the prudence with which personnel problems are handle. The main objectives of the study are to understand the current status of personnel management functions in the banks and to evaluate the practices in the light of the principles and theories of personnel management so as to identify the strengths and weaknesses. The universe of this study is the eight Scheduled Commercial Banks based in Kerala. The major limitation of the study is that as State Bank of Travancore, the lone public sector bank based in Kerala did not grant permission for collection of data, this study had to be confined to private sector banks only. Almost the entire data used for this study are primary and were collected from the files and other records or the concerned banks. This report has chapters dealing with the functional areas of personnel management such as determination of human resource requirements, recruitment and selection, training and development, performance appraisal, promotions and compensation. Findings reveal that the practice of personnel management in the Kerala-based private sector scheduled commercial banks has not gained a degree of sophistication compatible with its role in modern business management. |
| Description: | School of Management studies, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3251 |
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| Dyuthi-T1225.pdf | (16.19Mb) |
| Abstract: | The overall focus of the thesis involves the performer's rights in india -A study with special reference to the audiovisual industry.The performer is the disseminator of works of literary, dramatic artistic and musical authorship .The challenge of studying the audiovisual industry is the low level of data documentation and transparency in transactions compounded by the low awareness of legal issues. The first five chapters of the study trace the evolution of performers’ rights with particular impetus on three diverse jurisdictions both at the judicial and statutory levels as well as from the collective bargaining platform.The study also seeks to pin point the major obstacles that the performers have had to encounter in their quest for equal rights under the umbrella of intellectual property the world over.the status of the performer through the international instruments - the Rome convention, the WPPT and the envisaged Protocol to the audiovisual performance.A grant of rights to the performer either under Copyright or labor law need not improve matters for the performer unless the institutional grievance redressal is firmly put in place.There is a need for clearer delineation between the definitions of audio and audiovisual fixations. Under the Indian law the terms representing these have been sound records and cinematographs respectivel.Performer and the Philosophy of Intellectual Propertyeffectively. But this is not to deny the fact that these institutions, organizations and practices could very well rise to the occasion when the rights regime comes into force. |
| Description: | School of Legal Studies, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3061 |
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| Dyuthi-T1035.pdf | (10.77Mb) |
| Abstract: | The Kerala region which forms a significant segment of the south—western Indian shield, dominantly comprises charnockites, khondalites and migmatitic gneisses of Precambrian age. Recent investigations have revealed the occurrences of a number of younger granite and syenite plutons in this region, .spatially related to regional fault—lineaments. The granite of Ambalavayal in Wynad district of northern Kerala is a typical member of this suite of intrusives. The thesis is based on a comprehensive study in terms of geology, petrology, geochemistry and petrogenesis of the Ambalavayal granite, basement gneisses, associated pegmatites, quartz veins and related mineralization that together cover an area of about 90 sq km in wynad district of northern Kerala. |
| Description: | Centre for Earth Science Studies |
| URI: | http://dyuthi.cusat.ac.in/purl/3791 |
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| Dyuthi-T1735.pdf | (18.54Mb) |
| Abstract: | The Kerala region which forms a significant segment of the south—western Indian shield, dominantly comprises charnockites, khondalites and migmatitic gneisses of Precambrian age. Recent investigations have revealed the occurrences of a number of younger granite and syenite plutons in this region, .spatially related to regional fault—lineaments. The granite of Ambalavayal in Wynad district of northern Kerala is a typical member of this suite of intrusives. The thesis is based on a comprehensive study in terms of geology, petrology, geochemistry and petrogenesis of the Ambalavayal granite, basement gneisses, associated pegmatites, quartz veins and related mineralization that together cover an area of about 90 sq km in wynad district of northern Kerala |
| Description: | Centre for Earth Science Studies Trivandrum |
| URI: | http://dyuthi.cusat.ac.in/purl/3621 |
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| Dyuthi-T1601.pdf | (18.54Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1185 |
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| Santhosh M 1988.pdf | (1.416Mb) |
| Abstract: | In the present thesis the petrographic, geochemical and digenetic variability of the sediments in the islands of Kavaratti and Minicoy has been investigated .The beach profile studies show that in the Kavaratti lagoon beach, the slope is steeper in the southern and south central part than in the northern end’s marginal deposition is taking place in the northern end of the Kavaratti island, whereas a marginal erosion is observed at the southern end. In Minicoy the slope of the lagoon beach is gentle in the south and is slightly steeper at the northern part of the beach. The southern and northern beach sections show a marginal deposition. Based on the mineralogical and geochemical studies it is concluded that the main digenetic changes observed is the transformation of aragonite to LMC.The transformation takes place mainly in the vadose zone and is caused by the abundance of fresh water infiltration. |
| URI: | http://dyuthi.cusat.ac.in/purl/76 |
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| Dyuthi-T0184.pdf | (6.702Mb) |
| Abstract: | Poly(ethylene terephthalate) (PET) based nanocomposites have been prepared with single walled carbon nanotubes (SWNTs) through an ultrasound assisted dissolution-evaporation method. Differential scanning calorimetry studies showed that SWNTs nucleate crystallization in PET at weight fractions as low as 0.3%, as the nanocomposite melt crystallized during cooling at temperature 24 °C higher than neat PET of identical molecular weight. Isothermal crystallization studies also revealed that SWNTs significantly accelerate the crystallization process. Mechanical properties of the PETSWNT nanocomposites improved as compared to neat PET indicating the effective reinforcement provided by nanotubes in the polymer matrix. Electrical conductivity measurements on the nanocomposite films showed that SWNTs at concentrations exceeding 1 wt% in the PET matrix result in electrical percolation. Comparison of crystallization, conductivity and transmission electron microscopy studies revealed that ultrasound assisted dissolution-evaporation method enables more effective dispersion of SWNTs in the PET matrix as compared to the melt compounding method |
| URI: | http://dyuthi.cusat.ac.in/purl/795 |
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| Anoop Anand,K a ... omposites...,March2007.PDF | (5.914Mb) |
| Abstract: | Synchronization in an array of mutually coupled systems with a finite time delay in coupling is studied using the Josephson junction as a model system. The sum of the transverse Lyapunov exponents is evaluated as a function of the parameters by linearizing the equation about the synchronization manifold. The dependence of synchronization on damping parameter, coupling constant, and time delay is studied numerically. The change in the dynamics of the system due to time delay and phase difference between the applied fields is studied. The case where a small frequency detuning between the applied fields is also discussed. |
| URI: | http://dyuthi.cusat.ac.in/purl/2907 |
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| Dyuthi-P00406.pdf | (403.2Kb) |
| Abstract: | A forward - biased point contact germanium signal diode placed inside a waveguide section along the E -vector is found to introduce significant phase shift of microwave signals . The usefulness of the arrangement as a phase modulator for microwave carriers is demonstrated. While there is a less significant amplitude modulation accompanying phase modulation , the insertion losses are found to be negligible. The observations can be explained on the basis of the capacitance variation of the barrier layer with forward current in the diode |
| URI: | http://dyuthi.cusat.ac.in/purl/1432 |
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| Phase modulatio ... ermanium signal diodes.PDF | (882.1Kb) |
| Abstract: | We consider an array of N Josephson junctions connected in parallel and explore the condition for chaotic synchronization. It is found that the outer junctions can be synchronized while they remain uncorrelated to the inner ones when an external biasing is applied. The stability of the solution is found out for the outer junctions in the synchronization manifold. Symmetry considerations lead to a situation wherein the inner junctions can synchronize for certain values of the parameter. In the presence of a phase difference between the applied fields, all the junctions exhibit phase synchronization. It is also found that chaotic motion changes to periodic in the presence of phase differences. |
| URI: | http://dyuthi.cusat.ac.in/purl/2909 |
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| Dyuthi-P00408.pdf | (779.8Kb) |
| Abstract: | A detailed ultrasonic study of the elastic properties of lithium ammonium sulfate ~LiNH4SO4! or LAS has been carried out below room temperature. The elastic constants of LAS at room temperature are reported. The discrepancy present in earlier elastic constant data associated with the different choice of axes for this orthorhombic system are clarified. The results of the temperature variation study down to 220 K confirm the ferroelastic phase transition at 285 K and establish a thermal hysteresis of about 2.5 K between the cooling and heating cycles. Results of the investigation on the suspected weak phase transition at 256 K suggest that this transition occurs at 242 K on cooling and at 256 K on heating, thus having a thermal hysteresis of about 14 K. However, since the observed elastic anomaly for this transition is very small, the nature of this transition still remains unclear |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/1974 |
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| Godfry, L,.pdf | (116.4Kb) |
| Abstract: | Environmental persistence, fate and interactive effects with living organisms - beneficial or toxic - of trace elements are directly related to the physico-chemical forms in which they occur. Knowledge on the association of trace metals with different environmental compartments in an aquatic system are, therefore, essential for monitoring the trace metal pollution as well as transport, fate and bio-geochemical cycles of trace metals. This thesis is a modest attempt in assessing the trace metal levels and their behaviour in the aquatic environment of Kuttanad, an aquatic system that is severely affected by man's intervention on natural processes, by seriously evaluating the levels of trace metals in dissolved and particulate phases and also in the different chemical fractions of the sediments. |
| Description: | Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3525 |
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| Dyuthi-T1498.pdf | (4.420Mb) |
| Abstract: | This thesis is a modest attempt in assessing the trace metal levels and their behavior in the aquatic environment of Kuttanad, an aquatic system that is severely affected by man’s intervention on natural processes, by study seriously evaluating the levels of trace metals in dissolved and particulate phases and also in the different chemical fractions of the sediments. Understanding of the distributions, variations and transfer processes of trace metals in different environmental phases in the backwaters of Kuttanad is vital for the assessment of the water pollution problems and study the ecology of the area which contributes 20% of the rice production in the State of Kerala. Kuttand is a low-lying, shallow bay formed as a result of geological uplift. The major economic activity is agriculture involving 40% of the population. About 1.5% of the people are engaged in aquaculture. The trace metal distribution in the Kuttand backwaters is considerably influenced by the tropical features of the location and by human activities including agricultural activities and construction of salinity barrier. In this study an attempt is made to differentiate the metals in the sediment into exchangeable, reducible and resistant fractions in the sediments. |
| URI: | http://dyuthi.cusat.ac.in/purl/36 |
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| Dyuthi-T0183.pdf | (14.12Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5145 |
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| Dyuthi-T2179.pdf | (19.19Mb) |
| Abstract: | This thesis Entitled phenylethynylarene based Donor-Acceptor systems:Desigh,Synthesis and Photophysical studies. A strategy for the design of donor-acceptor dyads, wherein decay of the charge separated (CS) state to low lying local triplet levels could possibly be prevented, is proposed. In order to examine this strategy, a linked donor-acceptor dyad BPEPPT with bis(phenylethYlly/)pyrene (BPEP) as the light absorber and acceptor and phenothiazine (PT) as donor was designed and photoinduced electron transfer in the dyad investigated. Absorption spectra of the dyad can be obtained by adding contributions due 10 the BPEP and PT moieties indicating that the constituents do not interact in the ground stale. Fluorescence of the BPEP moiety was efficiently quenched by the PT donor and this was attributed to electron lransfer from PT to BPEP. Picosecond transient absorption studies suggested formation of a charge separated state directly from the singlet excited state of BPEP. Nanosecond flash photolysis experiments gave long-ived transient absorptions assignable to PT radical cation and BPEP radical anion. These assignments were confirmed by oxygen quenching studies and secondary electron transfer experiments. Based on the available data, energy level diagram for BPEP-PT was constructed. The long lifetime of the charge separated state was attributed to the inverted region effects. The CS state did not undergo decay to low lying BPEP triplet indicating the success of our strategy |
| Description: | Photosciences and Pholonics Chemical Sciences and Technology Division |
| URI: | http://dyuthi.cusat.ac.in/purl/3128 |
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| Dyuthi-T1102.pdf | (6.598Mb) |
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