| Abstract: | Computational Biology is the research are that contributes to the analysis of biological data through the development of algorithms which will address significant research problems.The data from molecular biology includes DNA,RNA ,Protein and Gene expression data.Gene Expression Data provides the expression level of genes under different conditions.Gene expression is the process of transcribing the DNA sequence of a gene into mRNA sequences which in turn are later translated into proteins.The number of copies of mRNA produced is called the expression level of a gene.Gene expression data is organized in the form of a matrix. Rows in the matrix represent genes and columns in the matrix represent experimental conditions.Experimental conditions can be different tissue types or time points.Entries in the gene expression matrix are real values.Through the analysis of gene expression data it is possible to determine the behavioral patterns of genes such as similarity of their behavior,nature of their interaction,their respective contribution to the same pathways and so on. Similar expression patterns are exhibited by the genes participating in the same biological process.These patterns have immense relevance and application in bioinformatics and clinical research.Theses patterns are used in the medical domain for aid in more accurate diagnosis,prognosis,treatment planning.drug discovery and protein network analysis.To identify various patterns from gene expression data,data mining techniques are essential.Clustering is an important data mining technique for the analysis of gene expression data.To overcome the problems associated with clustering,biclustering is introduced.Biclustering refers to simultaneous clustering of both rows and columns of a data matrix. Clustering is a global whereas biclustering is a local model.Discovering local expression patterns is essential for identfying many genetic pathways that are not apparent otherwise.It is therefore necessary to move beyond the clustering paradigm towards developing approaches which are capable of discovering local patterns in gene expression data.A biclusters is a submatrix of the gene expression data matrix.The rows and columns in the submatrix need not be contiguous as in the gene expression data matrix.Biclusters are not disjoint.Computation of biclusters is costly because one will have to consider all the combinations of columans and rows in order to find out all the biclusters.The search space for the biclustering problem is 2 m+n where m and n are the number of genes and conditions respectively.Usually m+n is more than 3000.The biclustering problem is NP-hard.Biclustering is a powerful analytical tool for the biologist.The research reported in this thesis addresses the problem of biclustering.Ten algorithms are developed for the identification of coherent biclusters from gene expression data.All these algorithms are making use of a measure called mean squared residue to search for biclusters.The objective here is to identify the biclusters of maximum size with the mean squared residue lower than a given threshold. All these algorithms begin the search from tightly coregulated submatrices called the seeds.These seeds are generated by K-Means clustering algorithm.The algorithms developed can be classified as constraint based,greedy and metaheuristic.Constarint based algorithms uses one or more of the various constaints namely the MSR threshold and the MSR difference threshold.The greedy approach makes a locally optimal choice at each stage with the objective of finding the global optimum.In metaheuristic approaches particle Swarm Optimization(PSO) and variants of Greedy Randomized Adaptive Search Procedure(GRASP) are used for the identification of biclusters.These algorithms are implemented on the Yeast and Lymphoma datasets.Biologically relevant and statistically significant biclusters are identified by all these algorithms which are validated by Gene Ontology database.All these algorithms are compared with some other biclustering algorithms.Algorithms developed in this work overcome some of the problems associated with the already existing algorithms.With the help of some of the algorithms which are developed in this work biclusters with very high row variance,which is higher than the row variance of any other algorithm using mean squared residue, are identified from both Yeast and Lymphoma data sets.Such biclusters which make significant change in the expression level are highly relevant biologically. |
| Description: | Dept.of Computer Science,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2956 |
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| Dyuthi-T0947.pdf | (8.801Mb) |
| Abstract: | Laser‐induced damage and ablation thresholds of bulk superconducting samples of Bi2(SrCa)xCu3Oy(x=2, 2.2, 2.6, 2.8, 3) and Bi1.6 (Pb)xSr2Ca2Cu3 Oy (x=0, 0.1, 0.2, 0.3, 0.4) for irradiation with a 1.06 μm beam from a Nd‐YAG laser have been determined as a function of x by the pulsed photothermal deflection technique. The threshold values of power density for ablation as well as damage are found to increase with increasing values of x in both systems while in the Pb‐doped system the threshold values decrease above a specific value of x, coinciding with the point at which the Tc also begins to fall. |
| URI: | http://dyuthi.cusat.ac.in/purl/2577 |
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| Dyuthi-P0137.pdf | (947.3Kb) |
| Abstract: | The dual-beam thermal lens technique has been found to be very effective for the measurement of fluorescence quantum yields of dye solutions. The concentration-dependence of the quantum yield of rhodamine B in methanol is studied here using this technique. The observed results are in line with the conclusion that the reduction in the quantum yield in the quenching region is essentially due to the non-radiative relaxation of the absorbed energy. The thermal lens has been found to become abberated above 40 mW of pump laser power. This low value for the upper limit of pump power is due to the fact that the medium is a resonantly absorbing one. |
| URI: | http://dyuthi.cusat.ac.in/purl/2453 |
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| Dyuthi-P0314.pdf | (115.8Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/2658 |
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| Dyuthi-P0339.pdf | (198.7Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/634 |
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| Adelman, j and ... th in situ,E1-2005-131.PDF | (11.52Mb) |
| Abstract: | A simple experimental set-up is described to measure the electromagnetic shielding property of high Tc superconducting samples. Measurements were performed using HTSC materials in the form of laser ablated thin films, powders and sintered pellets. Samples used were Gd-123 in pure and doped form as well as a few Bi-based superconducting ceramics. For comparison, similar measurements were carried out on metals like aluminium, copper and μ metal. Very effective shielding was observed for HTSC materials compared to the conventional materials mentioned above. However it also depended on the sample types and poor shielding was observed for powdered HTSC material in comparison to thin films prepared by laser ablation. |
| URI: | http://dyuthi.cusat.ac.in/purl/2657 |
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| Dyuthi-P0338.pdf | (195.2Kb) |
| Abstract: | The assessment of maturity of software is an important area in the general software sector. The field of OSS also applies various models to measure software maturity. However, measuring maturity of OSS being used for several applications in libraries is an area left with no research so far. This study has attempted to fill the research gap. Measuring maturity of software contributes knowledge on its sustainability over the long term. Maturity of software is one of the factors that positively influence adoption. The investigator measured the maturity of DSpace software using Woods and Guliani‟s Open Source Maturity Model-2005. The present study is significant as it addresses the aspects of maturity of OSS for libraries and fills the research gap on the area. In this sense the study opens new avenues to the field of library and information science by providing an additional tool for librarians in the selection and adoption of OSS. Measuring maturity brings in-depth knowledge on an OSS which will contribute towards the perceived usefulness and perceived ease of use as explained in the Technology Acceptance Model theory. |
| Description: | Department of Computer Applications |
| URI: | http://dyuthi.cusat.ac.in/purl/5012 |
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| Dyuthi-T2079.pdf | (3.633Mb) |
| Abstract: | High strength and high performance concrete are being widely used all over the world. Most of the applications of high strength concrete have been found in high rise buildings, long span bridges etc. The potential of rice husk ash as a cement replacement material is well established .Earlier researches showed an improvement in mechanical properties of high strength concrete with finely ground RHA as a partial cement replacement material. A review of literature urges the need for optimizing the replacement level of cement with RHA for improved mechanical properties at optimum water binder ratio. This paper discusses the mechanical properties of RHA- High strength concrete at optimized conditions |
| Description: | American Journal of Engineering Research (AJER),Volume-3 pp-14-19 |
| URI: | http://dyuthi.cusat.ac.in/purl/4643 |
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| Mechanical Prop ... High strength Concrete.pdf | (444.0Kb) |
| Abstract: | A series of short-isora-fiber-reinforced natural rubber composites were prepared by the incorporation of fibers of different lengths (6, 10, and 14 mm) at 15 phr loading and at different concentrations (10, 20, 30, and 40 phr) with a 10 mm fiber length. Mixes were also prepared with 10 mm long fibers treated with a 5% NaOH solution. The vulcanization parameters, processability, and stress-strain properties of these composites were analyzed. Properties such as tensile strength, tear strength, and tensile modulus were found to be at maximum for composites containing longitudinally oriented fibers 10 mm in length. Mixes containing fiber loadings of 30 phr with bonding agent (resorcinol-formaldehyde [RF] resin) showed mechanical properties superior to all other composites. Scanning electron microscopy (SEM) studies were carried out to investigate the fiber surface morphology, fiber pullout, and fiber-rubber interface. SEM studies showed that the bonding between the fiber and rubber was improved with treated fibers and with the use of bonding agent. |
| URI: | http://dyuthi.cusat.ac.in/purl/808 |
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| Lovely Mathew a ... roperties...,April2006.PDF | (8.573Mb) |
| Abstract: | This paper presents the results from an experimental program and an analytical assessment of the influence of addition of fibers on mechanical properties of concrete. Models derived based on the regression analysis of 60 test data for various mechanical properties of steel fiber-reinforced concrete have been presented. The various strength properties studied are cube and cylinder compressive strength, split tensile strength, modulus of rupture and postcracking performance, modulus of elasticity, Poisson’s ratio, and strain corresponding to peak compressive stress. The variables considered are grade of concrete, namely, normal strength 35 MPa , moderately high strength 65 MPa , and high-strength concrete 85 MPa , and the volume fraction of the fiber Vf =0.0, 0.5, 1.0, and 1.5% . The strength of steel fiber-reinforced concrete predicted using the proposed models have been compared with the test data from the present study and with various other test data reported in the literature. The proposed model predicted the test data quite accurately. The study indicates that the fiber matrix interaction contributes significantly to enhancement of mechanical properties caused by the introduction of fibers, which is at variance with both existing models and formulations based on the law of mixtures |
| Description: | Journal of Materials in Civil Engineering, Vol. 19, No. 5, May 1, 2007. |
| URI: | http://dyuthi.cusat.ac.in/purl/4537 |
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| Mechanical Prop ... er-Reinforced Concrete.pdf | (143.9Kb) |
| Abstract: | Mn1−xZnxFe2O4 nanoparticles (x = 0 to 1) were synthesized by the wet chemical co-precipitation technique. X-ray diffraction and transmission electron microscopy and high resolution transmission electron microscopy were effectively utilized to investigate the different structural parameters. The ac conductivity of nanosized Mn1−xZnxFe2O4 were investigated as a function of frequency, temperature and composition. The frequency dependence of ac conductivity is analysed by the power law σ(ω)ac = Bωn which is typical for charge transport by hopping or tunnelling processes. The temperature dependence of frequency exponent n was investigated to understand the conduction mechanism in different compositions. The conduction mechanisms are mainly based on polaron hopping conduction |
| Description: | J. Phys. D: Appl. Phys. 42 (2009) 165005 (8pp) |
| URI: | http://dyuthi.cusat.ac.in/purl/4397 |
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| Mechanism of ac ... se zinc mixed ferrites.pdf | (2.619Mb) |
| Abstract: | Polyfurfural thin films lying in the thickness range of 1300–2000 A˚ were prepared by ac plasma polymerization technique. The current–voltage characteristics in symmetric and asymmetric electrode configuration were studied with a view to determining the dominant conduction mechanism.It was found that the Schottky conduction mechanism is dominant in plasma polymerized furfural thin films.The predominance of Schottky mechanism was further confirmed based on the thermally stimulated current measurements. |
| URI: | http://dyuthi.cusat.ac.in/purl/2832 |
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| Dyuthi-P00388.pdf | (231.2Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1014 |
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| RAVEENDRAN NAIR B 1988.pdf | (259.7Kb) |
| Abstract: | The incidence of diabetes is rapidly increasing and by 2030 an expected 592 million individuals are projected to be affected (WHO report). Hyperglycaemic condition is recognized as the causal link between diabetes and its complications. The chronic hyperglycemia resulting from diabetes brings about a rise in oxidative stress due to overproduction of reactive oxygen species (ROS) as a result of glucose auto oxidation and protein glycosylation. Generation of ROS leads to oxidative damage of the structural components (such as lipids, DNA and proteins) of cells and potentiate diabetes related complications. Oxidative insult in cells is also created by the impairment in functioning of endogenous antioxidant enzymes because of their non enzymatic glycosylation and oxidation. The prolonged exposure of oxidative stress may cause insulin resistance by triggering an alteration in cellular redox balance. Several lines of evidence suggest that oxidative stress occurs in diabetes and could have a role in the development of insulin resistance. The cause and cellular mechanism responsible for this abnormality is not fully understand despite of intense investigative efforts. However it is unknown whether it is the cause or consequence of diabetes. Despite strong experimental evidence indicating that oxidative stress may determine the onset and progression of late-diabetic complications, controversy exists between the cause and associative relationship between oxidative stress and diabetes mellitus. Disruption of glucose homeostasis is a characteristic feature of Non-insulin dependent diabetes mellitus (NIDDM) and is associated with some complications including cardiovascular disease and renal failure. Glucose transport, the rate limiting step in glucose metabolism, can be activated in peripheral tissues by two distinct pathways. One stimulated by insulin through IRS-1/PI3K, Preface Page 2 the other by muscle contraction/exercise through the activation of AMPK. Both pathways also increase the phosphorylation and activity of MAPK family components of which p38 MAPK participates in the full activation of GLUT4.Insulin exerts its biological effect upon binding with the insulin receptor (IR) thereby activating the downstream signaling that lead to enhanced glucose uptake. In skeletal muscle, it potentiates glucose transport through PI3K mediated or non-PI3K mediated pathways. Alterations or defects in its signal transduction pathway was found in diabetic patients associated with decreased levels of IRb, IRS-1, and PI3K. In the insulin signaling, PI3K is a key molecule and inhibition of PI3K completely abolish insulin stimulated uptake. Akt or Pkb is an important downstream target of insulin stimulated glucose transport and metabolism.Impairment in fuel metabolism occurs in obesity, and this impairment is a leading pathogenic factor in type 2 diabetes. The insulin resistance associated with type 2 diabetes is most profound at the level of skeletal muscle as this is the primary site of glucose and fatty acid utilization. Therefore, an understanding of how to activate AMPK in skeletal muscle would offer significant pharmacologic benefits in the treatment of type 2 diabetes. Metformin and the thiazolidinedione drugs exert the effects via activation of AMPK. Activation of AMPK occurs in response to exercise, an activity known to have significant benefit for type 2 diabetics. AMPK serves as sensor of energy status whose activity is triggered in response to changes in nutritional status in order to modulate tissue-specific metabolic pathways |
| URI: | http://dyuthi.cusat.ac.in/purl/5151 |
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| Dyuthi-T2185.pdf | (9.806Mb) |
| Abstract: | Following the Majority Strategy in graphs, other consensus strategies, namely Plurality Strategy, Hill Climbing and Steepest Ascent Hill Climbing strategies on graphs are discussed as methods for the computation of median sets of pro¯les. A review of algorithms for median computation on median graphs is discussed and their time complexities are compared. Implementation of the consensus strategies on median computation in arbitrary graphs is discussed |
| Description: | Report/Econometric Institute, Erasmus University Rotterdam,EI 2007-34 |
| URI: | http://dyuthi.cusat.ac.in/purl/4218 |
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| Median computat ... g consensus strategies.pdf | (195.4Kb) |
| Abstract: | Median filtering is a simple digital non—linear signal smoothing operation in which median of the samples in a sliding window replaces the sample at the middle of the window. The resulting filtered sequence tends to follow polynomial trends in the original sample sequence. Median filter preserves signal edges while filtering out impulses. Due to this property, median filtering is finding applications in many areas of image and speech processing. Though median filtering is simple to realise digitally, its properties are not easily analysed with standard analysis techniques, |
| Description: | Department of Electronics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3364 |
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| Dyuthi-T1341.pdf | (5.349Mb) |
| Abstract: | The median of a profile = (u1, . . . , uk ) of vertices of a graph G is the set of vertices x that minimize the sum of distances from x to the vertices of . It is shown that for profiles with diameter the median set can be computed within an isometric subgraph of G that contains a vertex x of and the r -ball around x, where r > 2 − 1 − 2 /| |. The median index of a graph and r -joins of graphs are introduced and it is shown that r -joins preserve the property of having a large median index. Consensus strategies are also briefly discussed on a graph with bounded profiles. |
| Description: | Discrete Applied Mathematics 156 (2008) 2882–2889 |
| URI: | http://dyuthi.cusat.ac.in/purl/4216 |
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| The median func ... with bounded profiles.pdf | (410.2Kb) |
| Abstract: | A periphery transversal of a median graph G is introduced as a set of vertices that meets all the peripheral subgraphs of G. Using this concept, median graphs with geodetic number 2 are characterized in two ways. They are precisely the median graphs that contain a periphery transversal of order 2 as well as the median graphs for which there exists a profile such that the remoteness function is constant on G. Moreover, an algorithm is presented that decides in O(mlog n) time whether a given graph G with n vertices and m edges is a median graph with geodetic number 2. Several additional structural properties of the remoteness function on hypercubes and median graphs are obtained and some problems listed |
| Description: | University of Ljubljana Institute of Mathematics, Physics and Mechanics Department of Mathematics Preprint series, Vol. 46 (2008), 1046 |
| URI: | http://dyuthi.cusat.ac.in/purl/4237 |
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| Median Graphs, ... nd Geodetic Number Two.pdf | (256.4Kb) |
| Abstract: | A profile is a finite sequence of vertices of a graph. The set of all vertices of the graph which minimises the sum of the distances to the vertices of the profile is the median of the profile. Any subset of the vertex set such that it is the median of some profile is called a median set. The number of median sets of a graph is defined to be the median number of the graph. In this paper, we identify the median sets of various classes of graphs such as Kp − e, Kp,q forP > 2, and wheel graph and so forth. The median numbers of these graphs and hypercubes are found out, and an upper bound for the median number of even cycles is established.We also express the median number of a product graph in terms of the median number of their factors. |
| Description: | International Scholarly Research Network ISRN Discrete Mathematics Volume 2012, Article ID 583671, 8 pages doi:10.5402/2012/583671 |
| URI: | http://dyuthi.cusat.ac.in/purl/4212 |
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| Median Sets and Median Number of a Graph.pdf | (1.907Mb) |
| Description: | Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2669 |
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| Dyuthi-T0721.pdf | (4.766Mb) |
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