| URI: | http://dyuthi.cusat.ac.in/purl/5589 |
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| Dyuthi T-2630.pdf | (2.872Mb) |
| Abstract: | Measurement is the act or the result of a quantitative comparison between a given quantity and a quantity of the same kind chosen as a unit. It is generally agreed that all measurements contain errors. In a measuring system where both a measuring instrument and a human being taking the measurement using a preset process, the measurement error could be due to the instrument, the process or the human being involved. The first part of the study is devoted to understanding the human errors in measurement. For that, selected person related and selected work related factors that could affect measurement errors have been identified. Though these are well known, the exact extent of the error and the extent of effect of different factors on human errors in measurement are less reported. Characterization of human errors in measurement is done by conducting an experimental study using different subjects, where the factors were changed one at a time and the measurements made by them recorded. From the pre‐experiment survey research studies, it is observed that the respondents could not give the correct answers to questions related to the correct values [extent] of human related measurement errors. This confirmed the fears expressed regarding lack of knowledge about the extent of human related measurement errors among professionals associated with quality. But in postexperiment phase of survey study, it is observed that the answers regarding the extent of human related measurement errors has improved significantly since the answer choices were provided based on the experimental study. It is hoped that this work will help users of measurement in practice to better understand and manage the phenomena of human related errors in measurement. |
| Description: | School of Engineering, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3719 |
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| Dyuthi-T1675.pdf | (3.018Mb) |
| Abstract: | This thesis summarizes the results on the growth and characterisation of thin films of HA grown on TiAl6V4 (Ti) implant material at a lower substrate temperature by a combination of Pulsed laser deposition and a hydrothermal treatment to get sufficiently strong crystalline films suitable for orthopaedic applications. The comparison of the properties of the coated substrate has been made with other surface modification techniques like anodization and chemical etching. The in-vitro study has been conducted on the surface modified implants to assess its cell viability. A molecular level study has been conducted to analyze the adhesion mechanism of protein adhesion molecules on to HA coated implants. |
| Description: | Division of Mechanical Engineering, School of Engineering, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2132 |
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| Dyuthi-T0493.pdf | (5.084Mb) |
| Abstract: | The hazards associated with major accident hazard (MAH) industries are fire, explosion and toxic gas releases. Of these, toxic gas release is the worst as it has the potential to cause extensive fatalities. Qualitative and quantitative hazard analyses are essential for the identitication and quantification of the hazards associated with chemical industries. This research work presents the results of a consequence analysis carried out to assess the damage potential of the hazardous material storages in an industrial area of central Kerala, India. A survey carried out in the major accident hazard (MAH) units in the industrial belt revealed that the major hazardous chemicals stored by the various industrial units are ammonia, chlorine, benzene, naphtha, cyclohexane, cyclohexanone and LPG. The damage potential of the above chemicals is assessed using consequence modelling. Modelling of pool fires for naphtha, cyclohexane, cyclohexanone, benzene and ammonia are carried out using TNO model. Vapor cloud explosion (VCE) modelling of LPG, cyclohexane and benzene are carried out using TNT equivalent model. Boiling liquid expanding vapor explosion (BLEVE) modelling of LPG is also carried out. Dispersion modelling of toxic chemicals like chlorine, ammonia and benzene is carried out using the ALOHA air quality model. Threat zones for different hazardous storages are estimated based on the consequence modelling. The distance covered by the threat zone was found to be maximum for chlorine release from a chlor-alkali industry located in the area. The results of consequence modelling are useful for the estimation of individual risk and societal risk in the above industrial area.Vulnerability assessment is carried out using probit functions for toxic, thermal and pressure loads. Individual and societal risks are also estimated at different locations. Mapping of threat zones due to different incident outcome cases from different MAH industries is done with the help of Are GIS.Fault Tree Analysis (FTA) is an established technique for hazard evaluation. This technique has the advantage of being both qualitative and quantitative, if the probabilities and frequencies of the basic events are known. However it is often difficult to estimate precisely the failure probability of the components due to insufficient data or vague characteristics of the basic event. It has been reported that availability of the failure probability data pertaining to local conditions is surprisingly limited in India. This thesis outlines the generation of failure probability values of the basic events that lead to the release of chlorine from the storage and filling facility of a major chlor-alkali industry located in the area using expert elicitation and proven fuzzy logic. Sensitivity analysis has been done to evaluate the percentage contribution of each basic event that could lead to chlorine release. Two dimensional fuzzy fault tree analysis (TDFFTA) has been proposed for balancing the hesitation factor invo1ved in expert elicitation . |
| Description: | Division of Safety and Fire Engineering, School of Engineering, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2650 |
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| Dyuthi-T0710.pdf | (2.149Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5587 |
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| Dyuthi T-2628.pdf | (4.724Mb) |
| Abstract: | Chapter 1 presents a brief note on the state at which the construction industry stands at present, bringing into focus the significance of the critical study. Relevance of the study, area of investigation and objectives of the study are outlined in this chapter. The 2nd chapter presents a review of the literature on the relevant areas. In the third chapter an analysis on time and cost overrun in construction highlighting the major factors responsible for it has been done. A couple of case studies to estimate loss to the nation on account of delay in construction have been presented in the chapter. The need for an appropriate estimate and a competent contractor has been emphasised for improving effectiveness in the project implementation. Certain useful equations and thoughts have been formulated on this area in this chapter that can be followed in State PWD and other Govt. organisations. Case studies on project implementation of major projects undertaken by Government sponsored/supported organizations in Kerala have been dealt with in Chapter 4. A detailed description of the project of Kerala Legislature Complex with a critical analysis has been given in this chapter. A detailed account of the investigations carried out on the construction of International Stadium, a sports project of Greater Cochin Development Authority is included here. The project details of Cochin International Airport at Nedumbassery, its promoters and contractors are also discussed in Chapter 4. Various aspects of implementation which led the above projects successful have been discussed in chapter 5. The data collected were analysed through discussion and perceptions to arrive at certain conclusions. The emergence of front-loaded contract and its impact on economics of the project execution are dealt with in this chapter. Analysis of delays in respect of the various project narrated in chapter 3 has been done here. The root causes of the project time and overrun and its remedial measures are also enlisted in this chapter. Study of cost and time overrun of any construction project IS a part of construction management. Under the present environment of heavy investment on construction activities in India, the consequences of mismanagement many a time lead to excessive expenditure which are not be avoidable. Cost consciousness, therefore has to be keener than ever before. Optimization in investment can be achieved by improved dynamism in construction management. The successful completion of coristruction projects within the specified programme, optimizing three major attributes of the process - quality, schedule and costs - has become the most valuable and challenging task for the engineer - managers to perform. So, the various aspects of construction management such as cost control, schedule control, quality assurance, management techniques etc. have also been discussed in this fifth chapter. Chapter 6 summarises the conclusions drawn from the above criticalr1 of rhajor construction projects in Kerala. |
| Description: | School of Engineering,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3255 |
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| Dyuthi-T1229.pdf | (9.291Mb) |
| Abstract: | Over the past decade, there is a great demand for permission to transmit large bandwidth concurrent with existing narrowband signals. In 2002, the federal communications commission (FCC) decided to permit use of ultrawideband (UWB) systems. UWB systems are unique in their large instantaneous bandwidth and potential for lowcost digital design that enables a single system to operate in different modes as a communication device, radar etc. UWB systems aim at covering the frequency band of 3.1-10.6 GHz defined by the FCC. The addition of more and more features in each new generation communication system demands universal antennas suitable for operation in multiple bands. In this regard, designing a multiband antenna which also covers the UWB range without deteriorating the UWB performance is of great interest. Also, a significant issue in communication systems is to miniaturize the antenna size while providing good performance over the operation bands. The thesis presents three different designs of CPW-fed multiband antennas. The first design uses a fractal concept to achieve multiband operation. In the second and third designs, a slotted circular monopole and a spiral monopole are used respectively for multiband operation with UWB applications. For both these cases, variations from the basic antenna geometry are also proposed in which the frequency of operation is lowered without increase in overall antenna size. Design guidelines are developed for all antennas to facilitate design on substrates of different permittivity and thickness. The antennas are analyzed in both frequency and time domain for complete characterization |
| URI: | http://dyuthi.cusat.ac.in/purl/5217 |
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| Dyuthi T-2252.pdf | (10.45Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5484 |
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| Dyuthi T-2526.pdf | (13.13Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5193 |
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| Dyuthi T-2228.pdf | (24.00Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5579 |
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| Dyuthi T-2619.pdf | (11.13Mb) |
| Abstract: | Filters are one of the essential components in the RF and wireless communication systems. Small sized planar lowpass filters with good electrical characteristics along with low cost, light weight and ease of fabrication are highly desirable for the front end of modern communication systems to suppress harmonics and spurious signals. Design of compact lowpass filters with improved performance and diverse specifications for numerous applications is a huge challenge. In this thesis, high performance planar compact lowpass filters using multiple patch resonators on high impedance transmission line are developed. Design techniques of different types of patch resonators and their modifications to enhance the performance of the filters are presented.Patch resonators are designed by using high impedance short circuited stubs and low impedance open circuited patches. In the first stage of filter realization, compact lowpass filter having sharp roll-off using triangular and funnel patch resonators is presented. The structure is modified further to enhance the relative stopband bandwidth of the filter. In the third stage, another resonator has been introduced near the feed line to achieve sharp roll-off for the same cutoff frequency, stopband bandwidth and suppression level. To obtain compactness, high suppression level and wide stopband in filter design, low thickness substrate is tested and proved in the fourth stage. Realizations of planar compact lowpass filter with very sharp roll-off near the cutoff frequency have been presented using stepped impedance polygonal patch resonators. By increasing the patch size and number of resonators, the stopband bandwidth and suppression level have to be enhanced to a great extent. Enhancement of performance characteristics of lowpass filter design is continually being extended. By using high value capacitance patch, the stopband suppression level of the filter with sharp roll-off rate is achieved. Elliptic function lowpass filter with ultra-sharp roll-off is also developed using elliptic shaped patch resonators. Throughout the study, low cost substrate having permittivity 4.4 is used for the filter design. All the designed filters have been fabricated and predicted results are validated by the measurements. |
| URI: | http://dyuthi.cusat.ac.in/purl/5170 |
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| Dyuthi-T2204.pdf | (7.436Mb) |
| Abstract: | Electrocardiogram gives the information regarding the health of the patients by monitoring the bioelectric potentials generated by the sinoatrial node in the heart. These signals can be collected by using electrodes suitably placed on the body of a patient. The normal human ECG lie in the frequency range of 0.05-100 Hz and the most useful information is contained in the range of 0.5-45 Hz. Even though a large amount of work has already been done in the field of ECG classification, no classification system has made an attempt in identifying the isolated abnormalities which pose a silent threat to patients. An adaptive filtering technique for denoising the ECG which is based on Genetic Algorithm (GA) tuned Sign-Data Least Mean Square (SD-LMS) algorithm is proposed. This algorithm gave an average signal to noise ratio improvement of 10.75 dB for baseline wander and 24.26 dB for power line interference. It is seen that the step size ‘μ’ optimized with GA helps in obtaining better SNR value without causing any damage to the information content in the ECG. A new wavelet for automatic classification of arrhythmias from electrocardiogram is proposed. This new wavelet is formed as a sum of shifted Gaussians so that it resembles a normal ECG. This shape has been chosen with the aim of extracting maximum information from the ECG under analysis. The classification performance was studied using the most commonly used database, the MIT-BIH Arrhythmia database. The shifted and summed Gaussian wavelet was then optimized using GA. The optimum wavelet for classification was obtained after several runs of the GA algorithm. The ECG class labeling was done according to the Association for the Advancement of Medical Instrumentation (AAMI). The wavelet scales corresponding to the different frequency levels giving maximum classification performance were identified by selecting finer scales. Probabilistic Neural Network classifier was used for classification purpose. The proposed classification system offered better results than that reported in literature by giving an overall sensitivity of 97.01% for Normal beats, 75.20% for Supraventricular beats and 93.06% for Ventricular beats. As mentioned above this technique could exclusively identify some of the isolated abnormalities present in the patient records. |
| URI: | http://dyuthi.cusat.ac.in/purl/5143 |
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| Dyuthi-T2177.pdf | (4.847Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5225 |
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| Dyuthi T-2260.pdf | (65.15Mb) |
| Abstract: | The basic concepts of digital signal processing are taught to the students in engineering and science. The focus of the course is on linear, time invariant systems. The question as to what happens when the system is governed by a quadratic or cubic equation remains unanswered in the vast majority of literature on signal processing. Light has been shed on this problem when John V Mathews and Giovanni L Sicuranza published the book Polynomial Signal Processing. This book opened up an unseen vista of polynomial systems for signal and image processing. The book presented the theory and implementations of both adaptive and non-adaptive FIR and IIR quadratic systems which offer improved performance than conventional linear systems. The theory of quadratic systems presents a pristine and virgin area of research that offers computationally intensive work. Once the area of research is selected, the next issue is the choice of the software tool to carry out the work. Conventional languages like C and C++ are easily eliminated as they are not interpreted and lack good quality plotting libraries. MATLAB is proved to be very slow and so do SCILAB and Octave. The search for a language for scientific computing that was as fast as C, but with a good quality plotting library, ended up in Python, a distant relative of LISP. It proved to be ideal for scientific computing. An account of the use of Python, its scientific computing package scipy and the plotting library pylab is given in the appendix Initially, work is focused on designing predictors that exploit the polynomial nonlinearities inherent in speech generation mechanisms. Soon, the work got diverted into medical image processing which offered more potential to exploit by the use of quadratic methods. The major focus in this area is on quadratic edge detection methods for retinal images and fingerprints as well as de-noising raw MRI signals |
| Description: | School of Engineering Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4624 |
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| Dyuthi-T1816.pdf | (6.727Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5324 |
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| Dyuthi T-2360.pdf | (5.573Mb) |
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