Abstract: | The present thesis can be divided into three areas:1) the fabrication of a low temperature photo-luminescence and photoconductivity measuring unit 2) photo-luminescence in the chalcopyrite CulnSez and CulnS2 system for defect and composition analysis and 3) photo-luminescence and photo-conductivity of In:JS3. This thesis shows that photo-luminescence is one of most essential semiconductor characterization tool for a scientific group working on photovoltaics. Tools which can be robust, non-destructive, requiring minimal sample preparation for analysis and most informative of the device applications are sought after by industries and this thesis is towards establishing photo-luminescence as "THE" tool for semiconductor characterization. The possible application of photo-luminescence as a tool for compositional and quality analysis of semiconductor thin films has been worked upon by this thesis. Photo-conductivity complement photo-luminescence and together they provide all the information required for the fabrication of an opto-electronic device. |
Description: | Department of Physics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/2521 |
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Dyuthi-T0680.pdf | (13.78Mb) |
URI: | http://dyuthi.cusat.ac.in/purl/5252 |
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Dyuthi T-2288.pdf | (8.613Mb) |
Abstract: | Here we report measurements of third-order susceptibility χ(3), figure of merit F defined as χ(3)/α (where α is the absorption coefficient) and second hyperpolarizability 〈γ〉 of some metal substituted phthalocyanines and a naphthalocyanine in solutions of dimethyl formamide using degenerate four wave mixing at 532 nm under nanosecond excitation. It was found that among samples investigated, bis-naphthalocyanine possessed the highest value of 〈γ〉 followed by the bis-phthalocyanine. This observation is explained on the basis that bis-naphthalocyanine followed by bis-phthalocyanine has higher degree of π electron conjugation. |
URI: | http://dyuthi.cusat.ac.in/purl/2410 |
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Dyuthi-P0238.pdf | (107.3Kb) |
Abstract: | Rare earth exchanged Na–Y zeolites, H-mordenite, K-10 montmorillonite clay and amorphous silica-alumina were effectively employed for the continuous synthesis of nitriles. Dehydration of benzaldoxime and 4-methoxybenzaldoxime were carried out on these catalysts at 473 K. Benzonitrile (dehydration product) was obtained in near quantitative yield with benzaldoxime whereas; 4-methoxybenzaldoxime produces both Beckmann rearrangement (4-methoxyphenylformamide) as well as dehydration products (4-methoxy benzonitrile) in quantitative yields. The production of benzonitrile was near quantitative under heterogeneous reaction conditions. The optimal protocol allows nitriles to be synthesized in good yields through the dehydration of aldoximes. Time on stream (TOS) studies show decline in the activity of the catalysts due to neutralization of acid sites by the basic reactant and product molecules and water formed during the dehydration of aldoximes. |
URI: | http://dyuthi.cusat.ac.in/purl/2260 |
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Dyuthi-SS52.pdf | (205.9Kb) |
Abstract: | The main objective of the Research was to study the Delayering scheme implemented in FACT in all its aspects and to examine wlietlier implementation of delayering has contributed to improvement in organizational performance by improving managerial motivation and team effectiveness. To enable this, a post-delayering impact assessment was done by eliciting views and analyzing the perception of managers affected by the change programme. Organisation-wide Surveys were carried out as part of data collection - prior to, during and after implementation. The methodology adopted was the Case Study approach, which involved a longitudinal study of the Implementation process using tools such- as Observation, Opinion surveys and Interviews and relating the research findings with the theories/ studies on the subject for generalization and for drawing conclusions |
Description: | School of Management Studies Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3671 |
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Dyuthi-T1637.pdf | (4.398Mb) |
Abstract: | The density of states and the low temperature specific heat of higb-Tc superconductors are calculated in a functional integral formalism using the slave boson technique. The manybody calculation in a saddle point approximation shows that the Iow energy sector is dominated by 3 single band. The calculated values of density of states are in good agreement with experimental results. |
URI: | http://dyuthi.cusat.ac.in/purl/2563 |
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Dyuthi-P0122.pdf | (304.2Kb) |
Abstract: | Soil microorganisms play a main part in organic matter decomposition and are consequently necessary to soil ecosystem processes maintaining primary productivity of plants. In light of current concerns about the impact of cultivation and climate change on biodiversity and ecosystem performance, it is vital to expand a complete understanding of the microbial community ecology in our soils. In the present study we measured the depth wise profile of microbial load in relation with important soil physicochemical characteristics (soil temperature, soil pH, moisture content, organic carbon and available NPK) of the soil samples collected from Mahatma Gandhi University Campus, Kottayam (midland region of Kerala). Soil cores (30 cm deep) were taken and the cores were separated into three 10-cm depths to examine depth wise distribution. In the present study, bacterial load ranged from 141×105 to 271×105 CFU/g (10cm depth), from 80×105 to 131×105 CFU/g (20cm depth) and from 260×104 to 47×105 CFU/g (30cm depth). Fungal load varies from 124×103 to 27×104 CFU/g, from 61×103 to110×103 CFU/g and from 16×103 to 49×103 CFU/g at 10, 20 and 30 cm respectively. Actinomycetes count ranged from 129×103 to 60×104 CFU/g (10cm), from 70×103 to 31×104 CFU/g (20cm) and from 14×103 to 66×103 CFU/g (30cm). The study revealed that there was a significant difference in the depthwise distribution of microbial load and soil physico-chemical properties. Bacterial, fungal and actinomycetes load showed a decreasing trend with increasing depth at all the sites. Except pH all other physicochemical properties showed decreasing trend with increasing depth. The vertical profile of total microbial load was well matched with the depthwise profiles of soil nutrients and organic carbon that is microbial load was highest at the soil surface where organics and nutrients were highest |
Description: | Indian J. Edu. Inf. Manage., Vol. 1, No. 3 (Mar 2012) |
URI: | http://dyuthi.cusat.ac.in/purl/3936 |
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Depth wise vari ... eristics and nutrients.pdf | (396.0Kb) |
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) |
Abstract: | Propagation of electromagnetic waves through a microstrip line with 2D electromagnetic baud gap (EBG) structures of different geometrical shapes in the ground plane is investigated in this paper. Using transmission-line theory, the design equations for EBG structures are calculated. The measured, numerical. and simulated results are in gone) agreement |
URI: | http://dyuthi.cusat.ac.in/purl/1422 |
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Design and anal ... ent geometrical shapes.PDF | (923.1Kb) |
URI: | http://dyuthi.cusat.ac.in/purl/5205 |
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Dyuthi T-2240.pdf | (8.622Mb) |
Abstract: | This paper presents the optimal design of a sur- face mounted permanent magnet Brushless DC mo- tor (PMBLDC) meant for spacecraft applications. The spacecraft applications requires the choice of a torques motor with high torque density, minimum cogging torque, better positional stability and high torque to inertia ratio. Performance of two types of machine con¯gurations viz Slotted PMBLDC and Slotless PMBLDC with halbach array are compared with the help of analytical and FE methods. It is found that unlike a Slotted PMBLDC motor, the Slotless type with halbach array develops zero cogging torque without reduction in the developed torque. Moreover, the machine being coreless provides high torque to inertia ratio and zero magnetic stiction |
Description: | ECTI TRANSACTIONS ON ELECTRICAL ENG., ELECTRONICS, AND COMMUNICATIONS VOL.9, NO.1 February 2011 |
URI: | http://dyuthi.cusat.ac.in/purl/4483 |
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Design and Anal ... pacecraft Applications.pdf | (479.3Kb) |
Abstract: | This paper presents the design and development of a frame based approach for speech to sign language machine translation system in the domain of railways and banking. This work aims to utilize the capability of Artificial intelligence for the improvement of physically challenged, deaf-mute people. Our work concentrates on the sign language used by the deaf community of Indian subcontinent which is called Indian Sign Language (ISL). Input to the system is the clerk’s speech and the output of this system is a 3D virtual human character playing the signs for the uttered phrases. The system builds up 3D animation from pre-recorded motion capture data. Our work proposes to build a Malayalam to ISL |
Description: | 2009 World Congress on Nature & Biologically Inspired Computing (NaBIC 2009) |
URI: | http://dyuthi.cusat.ac.in/purl/4091 |
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Design and Deve ... tem for English-to-ISL.pdf | (299.6Kb) |
Abstract: | This work is aimed at building an adaptable frame-based system for processing Dravidian languages. There are about 17 languages in this family and they are spoken by the people of South India.Karaka relations are one of the most important features of Indian languages. They are the semabtuco-syntactic relations between verbs and other related constituents in a sentence. The karaka relations and surface case endings are analyzed for meaning extraction. This approach is comparable with the borad class of case based grammars.The efficiency of this approach is put into test in two applications. One is machine translation and the other is a natural language interface (NLI) for information retrieval from databases. The system mainly consists of a morphological analyzer, local word grouper, a parser for the source language and a sentence generator for the target language. This work make contributios like, it gives an elegant account of the relation between vibhakthi and karaka roles in Dravidian languages. This mapping is elegant and compact. The same basic thing also explains simple and complex sentence in these languages. This suggests that the solution is not just ad hoc but has a deeper underlying unity. This methodology could be extended to other free word order languages. Since the frame designed for meaning representation is general, they are adaptable to other languages coming in this group and to other applications. |
URI: | http://dyuthi.cusat.ac.in/purl/978 |
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Dyuthi-T0048.pdf | (1.404Mb) |
Abstract: | This is a Named Entity Based Question Answering System for Malayalam Language. Although a vast amount of information is available today in digital form, no effective information access mechanism exists to provide humans with convenient information access. Information Retrieval and Question Answering systems are the two mechanisms available now for information access. Information systems typically return a long list of documents in response to a user’s query which are to be skimmed by the user to determine whether they contain an answer. But a Question Answering System allows the user to state his/her information need as a natural language question and receives most appropriate answer in a word or a sentence or a paragraph. This system is based on Named Entity Tagging and Question Classification. Document tagging extracts useful information from the documents which will be used in finding the answer to the question. Question Classification extracts useful information from the question to determine the type of the question and the way in which the question is to be answered. Various Machine Learning methods are used to tag the documents. Rule-Based Approach is used for Question Classification. Malayalam belongs to the Dravidian family of languages and is one of the four major languages of this family. It is one of the 22 Scheduled Languages of India with official language status in the state of Kerala. It is spoken by 40 million people. Malayalam is a morphologically rich agglutinative language and relatively of free word order. Also Malayalam has a productive morphology that allows the creation of complex words which are often highly ambiguous. Document tagging tools such as Parts-of-Speech Tagger, Phrase Chunker, Named Entity Tagger, and Compound Word Splitter are developed as a part of this research work. No such tools were available for Malayalam language. Finite State Transducer, High Order Conditional Random Field, Artificial Immunity System Principles, and Support Vector Machines are the techniques used for the design of these document preprocessing tools. This research work describes how the Named Entity is used to represent the documents. Single sentence questions are used to test the system. Overall Precision and Recall obtained are 88.5% and 85.9% respectively. This work can be extended in several directions. The coverage of non-factoid questions can be increased and also it can be extended to include open domain applications. Reference Resolution and Word Sense Disambiguation techniques are suggested as the future enhancements |
Description: | Dept. Of Computer Science Cochin University Of Science And Technology |
URI: | http://dyuthi.cusat.ac.in/purl/3698 |
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Dyuthi-T1663.pdf | (4.368Mb) |
URI: | http://dyuthi.cusat.ac.in/purl/5614 |
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Dyuthi T-2654.pdf | (1.977Mb) |
Abstract: | The design and development of a cost-effective, simple, sensitive and portable LED based fiber optic evanescent wave sensor for simultaneously detecting trace amounts of chromium and nitrite in water are presented. In order to obtain the desired performance, the middle portions of two multimode plastic clad silica fibers are unclad and are used as the sensing elements in the two arms of the sensor. Each of the sensor arms is sourced by separate super bright green LEDs, which are modulated in a time-sharing manner and a single photo detector is employed for detecting these light signals. The performance and characteristics of this system clearly establish the usefulness of the technique for detecting very low concentrations of the dissolved contaminants. |
URI: | http://dyuthi.cusat.ac.in/purl/2594 |
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Dyuthi-P0154.pdf | (176.0Kb) |
Abstract: | The present study shows design and development of a performance evaluation prototype for IT organizations in the context of outsourcing. The main objective of this research is to help an IT organization in the context of outsourcing to realize its current standing, so it can take corrective steps where ever necessary and strive for continuous improvement. Service level management (SLM) process plays a crucial role in controlling the quality provision for IT service. Out sourcing is the process of entrusting the responsibility of providing certain goods and services to an external party. We have tried to identify as many as twenty complexities and categorized in to four headings. Complexities associated with contracts and SLAs,SLM process,SLM organization and complexities due to intrinsic characteristics. In this study it is possible to measure the quality of the performance of an IT organization in an outsourcing environment effectively |
URI: | http://dyuthi.cusat.ac.in/purl/999 |
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Dyuthi-T0334.pdf | (6.423Mb) |
Abstract: | For the scientific and commercial utilization of Ocean resources, the role of intelligent underwater robotic systems are of great importance. Scientific activities like Marine Bio-technology, Hydrographic mapping, and commercial applications like Marine mining, Ocean energy, fishing, aquaculture, cable laying and pipe lining are a few utilization of ocean resources. As most of the deep undersea exploration are beyond the reachability of divers and also as the use of operator controlled and teleoperated Remotely Operated Vehicles (ROVs) and Diver Transport Vehicles (DTVs) turn out to be highly inefficient, it is essential to have a fully automated system capable providing stable control and communication links for the unstructured undersea environment. |
Description: | OCEANS 2003. Proceedings,VOL 1 |
URI: | http://dyuthi.cusat.ac.in/purl/4477 |
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Design and Deve ... Manipulator Controller.pdf | (74.67Kb) |
Abstract: | Antennas are indispensable component of any wireless communication device. An antenna is a transducer between the transmitter and the free space waves and vice versa. They efficiently transfer electromagnetic energy from a transmission line into free space. But the present day communication applications require compact and ultra wide band designs which cannot be catered by simple microstrip based designs. PIFAs have solved the problem to some extend, but the field of antennas needs more innovative designs In this thesis the design and development of compact planner antenna are presented. Emphasis is given to the design of the feed as well as the radiator resulting in simple compact uniplanar geometries. The Asymmetric coplanar feed used to excite the antennas is found to be a suitable choice for feeding compact antennas.The main objectives of the study are the design of compact single, dual and multi band antennas with uniplanar structure and extension of the design for practical GSM/WLAN applications and Ultra compact antennas using the above techniques and extension of the design to antennas for practical applications like RFID/DVB-H. All the above objectives are thoroughly studied. Antennas with ultra compact dimensions are obtained as a result of the study. Simple equations are provided to design antennas with the required characteristics. The design equations are verified by designing different antennas for different applications. |
Description: | Department of Electronics, Cochin University of Science and Technology |
URI: | http://dyuthi.cusat.ac.in/xmlui/purl/1927 |
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Dyuthi-T0388.pdf | (10.97Mb) |
Abstract: | The main objective of this thesis is to develop a compact chipless RFID tag with high data encoding capacity. The design and development of chipless RFID tag based on multiresonator and multiscatterer methods are presented first. An RFID tag using using SIR capable of 79bits is proposed. The thesis also deals with some of the properties of SIR like harmonic separation, independent control on resonant modes and the capability to change the electrical length. A chipless RFID reader working in a frequency band of 2.36GHz to 2.54GHz has been designed to show the feasibility of the RFID system. For a practical system, a new approach based on UWB Impulse Radar (UWB IR) technology is employed and the decoding methods from noisy backscattered signal are successfully demonstrated. The thesis also proposes a simple calibration procedure, which is able to decode the backscattered signal up to a distance of 80cm with 1mW output power. |
URI: | http://dyuthi.cusat.ac.in/purl/4992 |
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Dyuthi-T2061.pdf | (57.41Mb) |
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