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Applications of some discrete regression models for count data
B. M. Golam Kibria
Pakistan Journal of Statistics and Operation Research , 2006, DOI: 10.1234/pjsor.v2i1.81
Abstract: In this paper we have considered several regression models to fit the count data that encounter in the field of Biometrical, Environmental, Social Sciences and Transportation Engineering. We have fitted Poisson (PO), Negative Binomial (NB), Zero-Inflated Poisson (ZIP) and Zero-Inflated Negative Binomial (ZINB) regression models to run-off-road (ROR) crash data which collected on arterial roads in south region (rural) of Florida State. To compare the performance of these models, we analyzed data with moderate to high percentage of zero counts. Because the variances were almost three times greater than the means, it appeared that both NB and ZINB models performed better than PO and ZIP models for the zero inflated and over dispersed count data.
Effect of acrylic polymers on physical parameters of spheronized pellets using an aqueous coating system
Akhter Afsana,Kibria Golam
Asian Journal of Pharmaceutics , 2009,
Abstract: The aim of this study was to develop ambroxol hydrochloride sustained release pellets by an extrusion-spheronization technique and subsequent coating with acrylic polymers. Acrylic polymers like Eudragit RL 30 D, Eudragit RS 30 D and Eudragit NE 30 D were used as release retarding coating polymers. The release retarding capability of these polymers was also investigated. In each case, 10% polymer on dry basis was loaded. The flow property, surface roughness as well as the drug release behavior of the pellets was found to be the subject of types of polymers. About 35% drug was released at the first hour in 0.1N HCl media (pH 1.2) from Eudragit RL 30 D-coated pellets but from Eudragit RS 30 D and Eudragit NE 30 D-coated pellets, only 13.75 and 2.43% drug was released, respectively. In buffer media (pH 6.8), about 54% drug was released at the first hour from Eudragit RL 30 D-coated pellets but only 64% drug was released at 10 h. From Eudragit RL 30 D- and Eudragit NE 30 D-coated pellets only 7.28 and 1.14% drug was released at 1 h, respectively, but about 5.14 and 5.86 h was required for 50% drug release from these two polymers and about 80% drug was released at 10 h. The functional groups present in the polymeric films played a significant role on in vitro release kinetics of the drug from the coated pellets. Different kinetic models like zero order, first order and Higuchi were used for fitting the drug release pattern. The Higuchi model was the best fitted for ambroxol release from the coated pellets. The drug release mechanism was derived with Korsmeyer equation.
An efficient algorithm for weighted sum-rate maximization in multicell downlink beamforming
Mirza Golam Kibria,Hidekazu Murata
Computer Science , 2013, DOI: 10.1587/transfun.E97.A.69
Abstract: This paper considers coordinated linear precoding for rate optimization in downlink multicell, multiuser orthogonal frequency- division multiple access networks. We focus on two different design criteria. In the first, the weighted sum-rate is maximized under transmit power constraints per base station. In the second, we minimize the total transmit power satisfying the signal-to-interference-plus-noise-ratio constraints of the subcarriers per cell. Both problems are solved using standard conic optimization packages. A less complex, fast, and provably convergent algorithm that maximizes the weighted sum-rate with per-cell transmit power constraints is formulated. We approximate the nonconvex weighted sum- rate maximization (WSRM) problem with a solvable convex form by means of a sequential parametric convex approximation approach. The second- order cone formulations of an objective function and the constraints of the optimization problem are derived through a proper change of variables, first-order linear approximation, and hyperbolic constraints transformation. This algorithm converges to the suboptimal solution while taking fewer it- erations in comparison to other known iterative WSRM algorithms. Numerical results are presented to demonstrate the effectiveness and superiority of the proposed algorithm.
On the Liu and almost unbiased Liu estimators in the presence of multicollinearity with heteroscedastic or correlated errors
Mustafa I. Alheety,B. M. Golam Kibria
Surveys in Mathematics and its Applications , 2009,
Abstract: This paper introduces a new biased estimator, namely, almost unbiased Liu estimator (AULE) of β for the multiple linear regression model with heteroscedastics and/or correlated errors and suffers from the problem of multicollinearity. The properties of the proposed estimator is discussed and the performance over the generalized least squares (GLS) estimator, ordinary ridge regression (ORR) estimator (Trenkler, 1984), and Liu estimator (LE) (Ka iranlnar, 2003) in terms of matrix mean square error criterion are investigated. The optimal values of d for Liu and almost unbiased Liu estimators have been obtained. Finally, a simulation study has been conducted which indicated that under certain conditions on d, the proposed estimator performed well compared to GLS, ORR and LE estimators.
Exact Distribution of the Ratio of Gamma and Rayleigh Random Variables
M. Shakil,B. M. Golam Kibria
Pakistan Journal of Statistics and Operation Research , 2006, DOI: 10.1234/pjsor.v2i2.91
Abstract: The distributions of the ratio of two independent random variables arise in many applied problems and have been extensively studied by many researchers. This article derives the distributions of the ratio Z=|x/y| , when x and y are gamma and Rayleigh random variables respectively and are distributed independently of each other. The associated pdf, cdf, and moments have been given in terms of different special functions, for examples, confluent hypergeometric function, parabolic-cylinder function and beta functions. Some plots for the cdf and pdf associated with the distribution of the ratio have been provided.
Formulation and evaluation of domperidone pellets prepared by powder layering technology
Kibria Golam,Akhter Afsana,Ariful Islam K
Asian Journal of Pharmaceutics , 2010,
Abstract: The goal of the present study is to evaluate the influence of the formulation and operating conditions on pellet preparation by the pan technique. The effect of initial core weight on the physical parameters of pellets as well as to conduct stability study was also the goal of this study. For this domperidone maleate was selected as the model drug. Pellets were prepared by layering of powdered drug on sugar-based cores. Inert cores were intermittently treated with micronized drug powder and binding solution. This treatment led to the formation of multiple layers of drug particles around an inert core resulting in the production of pellets that can further be coated by different polymers to obtain modified release formulations. Scanning electron microscopy was employed to image the surface morphology of the prepared pellets. Drug loading efficiency, % yield, size, and shape uniformity of pellets were increased along with increasing the initial core weight. Drug content and dissolution study were performed by following HPLC and UV-Visible method. About 50% and 80% drug was released within 7.72 m and 13.66 m respectively in 0.1N HCl media (pH 1.2). Physical appearance of the prepared pellets, potency, moisture content, pellets size and shape, dissolution data, release rate constant, diffusion exponent (P< .05) over the stability period showed that the system is efficient for the production of highly stable formulations. This study also showed the good performance of the conventional coating pan system in obtaining instant release domperidone pellets prepared by the powder layering technique.
IN VITRO CYTOTOXIC EFFECT OF METHANOLIC CRUDE EXTRACTS OF TERMINALIA CHEBULA
Md.Golam Kibria,Mohammad Musarraf Hussain
International Research Journal of Pharmacy , 2012,
Abstract: The aim of this work is to observe invitro cytotoxic effect of methanolic crude extracts of Terminalia chebula (Family: Combretaceae). The bark of Terminalia chebula were soaked with methanol and then methanolic crude extract was fractionated into n-hexane, ethyl acetate, and chloroform soluble fractions. The methanolic crude extracts (n-hexane, ethyl acetate, and chloroform soluble fractions) of Terminalia chebula were screened for cytotoxic activity using brine shrimp lethality bioassay. A reputed cytotoxic agent vincristine sulphate used as a positive control. From the results of the brine shrimp lethality bioassay it can be well predicted that methanolic crude extracts (n-hexane, ethyl acetate and chloroform soluble fractions) of Terminalia chebula possess cytotoxic principles, (LC50 1.413 mg/mL, 1.492 mg/mL and 1.496 mg/mL respectively) comparison with positive control, vincristine sulphate (LC50 0.563 mg/mL).
Improved Liu Estimators for the Poisson Regression Model
Kristofer Mansson,B. M. Golam Kibria,Par Sjolander,Ghazi Shukur
International Journal of Statistics and Probability , 2012, DOI: 10.5539/ijsp.v1n1p2
Abstract: A new shrinkage estimator for the Poisson model is introduced in this paper. This method is a generalization of the Liu (1993) estimator originally developed for the linear regression model and will be generalized here to be used instead of the classical maximum likelihood (ML) method in the presence of multicollinearity since the mean squared error (MSE) of ML becomes inflated in that situation. Furthermore, this paper derives the optimal value of the shrinkage parameter and based on this value some methods of how the shrinkage parameter should be estimated are suggested. Using Monte Carlo simulation where the MSE and mean absolute error (MAE) are calculated it is shown that when the Liu estimator is applied with these proposed estimators of the shrinkage parameter it always outperforms the ML.
The Right of Getting Bail of an Arrested Person in Bangladesh—A Legal Study of Theories and Practice  [PDF]
Shahidul Islam, Golam Moula
Beijing Law Review (BLR) , 2014, DOI: 10.4236/blr.2014.51004
Abstract:

The essential sense of the Bail in Bangladesh is to release a person from the custody of police and deliver him/her into the hands of the sureties who undertake to produce him in court whenever required to do so. The word Bail is derived from the old French verb “Bailer” which means to “give” or to “deliver”1 (Webster’s Dictionary, 1938). In common Law legal system, it is found that an accused person is to be declared on bail, when he is released from the custody of the officers of the Court. The sureties are bound to produce him to answer at a specified date, time and place, the accusation against him when bail is approved by the competent court. The basic principle regarding release on bail is that an accused person is presumed in law to be entitled to freedom and every opportunity to look after his case, provided his attendance is secured by proper security. However, the paper focuses the idea of releasing an accused on bail in such a case that has been developed as of right of an accused in our country. Therefore, this paper gives emphasis on bail of an accused on legal analysis on theoretical and practical approach and it recommends that the bail granting authority should maintain the principles of law as well as provisions of law properly for the protection rights of an accused.

Actin - Technical Report
Raihan H. Kibria
Computer Science , 2007,
Abstract: The Boolean satisfiability problem (SAT) can be solved efficiently with variants of the DPLL algorithm. For industrial SAT problems, DPLL with conflict analysis dependent dynamic decision heuristics has proved to be particularly efficient, e.g. in Chaff. In this work, algorithms that initialize the variable activity values in the solver MiniSAT v1.14 by analyzing the CNF are evolved using genetic programming (GP), with the goal to reduce the total number of conflicts of the search and the solving time. The effect of using initial activities other than zero is examined by initializing with random numbers. The possibility of countering the detrimental effects of reordering the CNF with improved initialization is investigated. The best result found (with validation testing on further problems) was used in the solver Actin, which was submitted to SAT-Race 2006.
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