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匹配条件: “K. Sumathi” ,找到相关结果约138253条。
Selection of Variables in Regression Models Based on Inflated Distributions
Aruna Rao,Sumathi K
Pakistan Journal of Statistics and Operation Research , 2011, DOI: 10.1234/pjsor.v7i2-sp.300
Abstract: Regression models based on zero inflated distributions are oftenly used in exploratory data analysis having excess zeroes. The difficulty faced by many researchers is regarding the selection of covariates to be included in the model. Following the idea of focused information criterion, observed focused information criterion is proposed for model selection. The motivation for this has its roots in the concept of observed fisher information. Using this criterion, a forward selection procedure is proposed for selection of variables in regression models based on inflated distributions. The procedure is illustrated using a dataset on DMFT index using the modified observed focused information criterion.
Theoretical Evaluation of Ultrasonic Velocities in Ternary Liquid Mixtures of Dibutylether + Toluene + 1-Alkanols at 303K
T. Sumathi,K. Abeetha
Journal of Chemistry , 2011, DOI: 10.1155/2011/192139
Sumathi K,Aruna Rao K
Pakistan Journal of Statistics and Operation Research , 2011, DOI: 10.1234/pjsor.v7i1.158
Abstract: The score test proposed by Rao (1947) has been widely used in the recent years for data analysis and model building because of its simplicity. However, at the time of its computation, it has been found that the value of the score test statistic becomes negative. Freedman (2007) discussed some of the theoretical reasons for this inconsistency of the score test and observed that the test was inconsistent when the observed Fisher information matrix was used rather than the expected Fisher information matrix. The present paper is an attempt to demonstrate the inconsistency of the score test in terms of the power function.
Development of Cache Oblivious Based Fast Multiple Longest Common Subsequence Technique(CMLCS) for Biological Sequences Prediction
A. Sumathi,N. K. Sakthivel
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: A biological sequence is a single, continuous molecule of nucleic acid or protein. Classical methods for the Multiple Longest Common Subsequence problem (MLCS) problem are based on dynamic programming. The Multiple Longest Common Subsequence problem (MLCS) is used to find the longest subsequence shared between two or more strings. For over 30 years, significant efforts have been made to find efficient algorithms for the MLCS problem. Many of them have been proposed for the general case of any given number of strings. They could benefit greatly from improving their computation times. (Qingguo et al.,) proposed a new algorithm for the general case of Multiple LCS problem, which is finding the LCS of any number of strings. This algorithm is based on the dominant point approach and employs a fast divide-and-conquers technique to compute the dominant points. From this existing work, it is observed that, when this approach is applied to a case of three strings, this algorithm demonstrates the same performance as the fastest existing MLCS algorithm. When applied to more than three strings, this technique is significantly faster than the existing sequential methods, reaching up to 2-3 orders of magnitude faster speed on large-size problems. However, from our experimental results, it is observed that as the size of the Data Set is increasing, its performance decreases in terms of execution time. To overcome this major issue, we have developed an efficient model called Cache Oblivious based Multiple Longest Common Subsequence (CMLCS). From our experimental results, it is observed that our proposed work performs better as compared with the existing system in terms of Execution Time and Memory Usage.
J. K. Jain,Sumathi Rao
Physics , 1995, DOI: 10.1142/S0217984995000577
Abstract: Motivated by a mean-field approach, which has been employed for anyon superfluidity and the fractional quantum Hall effect, the quantum Hall effect (QHE) of hard-core bosons is investigated. It is shown that QHE is possible {\em only} in the thermodynamic limit. The filling factors where QHE may be expected are obtained with the help of two adiabatic schemes.
Ranjan K. Ghosh,Sumathi Rao
Physics , 1995,
Abstract: We find that the energy spectra of four and five anyons in a harmonic potential exhibit some mirror symmetric (reflection symmetric about the semionic statistics point $\theta=\pi/2$) features analogous to the mirror symmetry in the two and three anyon spectra. However, since the $\ell=0$ sector remains non-mirror symmetric, the fourth and fifth virial coeffients do not reflect this symmetry.
Fractional Quantum Hall Effect States as Exact Ground States
Ranjan K. Ghosh,Sumathi Rao
Physics , 1997, DOI: 10.1142/S0217979298000612
Abstract: We construct many particle Hamiltonians for which the Laughlin and Jain wavefunctions are exact ground states. The Hamiltonians involve fermions in a magnetic field and with inter-particle interactions. For the Laughlin wave-functions,the interactions involve two- and three-body correlations similar to the Chern-Simons interactions, whereas for the projected Jain wave-functions, N-body interactions (which cannot be explicitly written down in general) are involved.
Transport in a class of exactly solvable models of interacting fermions
P. K. Mohanty,Sumathi Rao
Physics , 1999, DOI: 10.1088/0305-4470/33/41/308
Abstract: We study transport in a class of exactly solvable models of interacting fermions in one dimension. We contrast these models with models of non-interacting fermions in an Aharanov-Bohm ring to which they are superficially similar. We introduce magnetic and non-magnetic impurities at a site, through either a weak $\delta$-function potential or through a weak link. Using a renormalisation group analysis, we show that the strength of the nonmagnetic impurity is not affected by the interaction, whereas the magnetic impurity cuts the wire at the impurity site.
Exactly Solvable Models in Arbitrary Dimensions
Ranjan K. Ghosh,Sumathi Rao
Physics , 1997, DOI: 10.1016/S0375-9601(97)00826-8
Abstract: We construct a new class of quasi-exactly solvable many-body Hamiltonians in arbitrary dimensions, whose ground states can have any correlations we choose. Some of the known correlations in one dimension and some recent novel correlations in two and higher dimensions are reproduced as special cases. As specific interesting examples, we also write down some new models in two and higher dimensions with novel correlations.
Detection of Link Fault Using Risk Modelling and Improving QOS Parameters in IP/WDM Networks  [PDF]
K. Sashi Rekha, M. Sumathi
Circuits and Systems (CS) , 2016, DOI: 10.4236/cs.2016.79193
Abstract: An operational backbone network is connected with many routers and other devices. Identifying faults in the network is very difficult, so a fault localization mechanism is necessary to identify fault and alleviate it and correct the faults in order to reduce the network performance degradation. A risk model needs to be devised based on the dynamic database by creating alternate path and the network is reconfigured by identifying dynamic paths. In this paper, an on-demand link state routing approach is used for handling failures in IP backbone networks and a localization algorithm is used to improve QOS parameters based on threshold value of gateway. It is proved that on-demand link state routing guarantees loop-free forwarding to reachable destinations regardless of the number of failures in the network, and in case of localization algorithm using modification process packet loss is avoided based on threshold value of gateway. Heuristic algorithm is also used for reconfiguration of dynamic path for effective fault localization. In this paper, in order to change the traffic condition, reconfiguration strategic is dynamically used. Dijikstra’s shortest path algorithm has been used to determine the shortest path between node pairs. Using risk modeling mechanism, a small set of candidate faults is identified. The concept of Fault Localization is used to minimize the fault occurring in the node and sends original path to node pairs. The localization algorithm based on MODIFICATION PROCESS, packet loss is avoided in the network by checking threshold value of gateway. If the threshold value is maximum, router directly forwards the packet to destination through gateway and if the threshold value is minimum, router compresses the packet and forwards the packet to destination with notification via gateway.

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