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Global Journal of Mathematical Sciences最新文献

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A crack originating from a semicircular notch in a non homogeneous sheared half-plane 裂缝:在非均匀剪切半平面上由半圆形缺口产生的裂缝
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/GJMAS.V8I1.50815
J. Nnadi
{"title":"A crack originating from a semicircular notch in a non homogeneous sheared half-plane","authors":"J. Nnadi","doi":"10.4314/GJMAS.V8I1.50815","DOIUrl":"https://doi.org/10.4314/GJMAS.V8I1.50815","url":null,"abstract":"An interfacial crack originates from a semi circular notch in a non-homogeneous semi infinite elastic material subjected to constant shear loads of magnitudes Tj, j = 1, 2. Asymptotic deformation fields near the crack tip are derived in a closed form. The stress intensity factor is shown to depend on material constants except when equal and opposite tractions are applied on load sites of equal length. Our results agree with known ones.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"2005 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125832593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Transformation of independent variables in polynomial regression models 多项式回归模型中自变量的变换
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/GJMAS.V8I1.50810
A. Okolo
{"title":"Transformation of independent variables in polynomial regression models","authors":"A. Okolo","doi":"10.4314/GJMAS.V8I1.50810","DOIUrl":"https://doi.org/10.4314/GJMAS.V8I1.50810","url":null,"abstract":"In representing a relationship between a response and a number of independent variables, it is preferable when possible to work with a simple functional form in transformed variables rather than with a more complicated form in the original variables. In this paper, it is shown that linear transformations applied to independent variables in polynomial regression models affect the t ratio and hence the statistical significance for certain parameters of the polynomial regression models.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115376540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Asymptotic stability results for retarded differential systems 时滞微分系统的渐近稳定性结果
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/GJMAS.V8I1.50811
D. Igobi, M. Egwurube, M. R. Odekunle
{"title":"Asymptotic stability results for retarded differential systems","authors":"D. Igobi, M. Egwurube, M. R. Odekunle","doi":"10.4314/GJMAS.V8I1.50811","DOIUrl":"https://doi.org/10.4314/GJMAS.V8I1.50811","url":null,"abstract":"The transcendental character of the polynomial equation of the retarded differential system makes it difficult to express its solution explicitly. This has cause a set back in the asymptotic stability analysis of the system solutions. Various acceptable mathematical techniques have been used to address the issue. In this paper, the integral-differential equation and the positive symmetric properties of given matrices are used in formulating a Lyapunov functional. The introduction of convex set segment of a symmetric matrix is explored to establish boundedness of the first derivative of the formulated functional. The integral-differential equation is utilized in computing the maximum delay interval for the system to attain stability. Its application to numerical problems confirms the suitability of the test.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132746126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On the problems of PPS sampling in multi-character surveys 多字符调查中PPS抽样问题研究
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/gjmas.v8i1.50812
A. C. Akpanta
{"title":"On the problems of PPS sampling in multi-character surveys","authors":"A. C. Akpanta","doi":"10.4314/gjmas.v8i1.50812","DOIUrl":"https://doi.org/10.4314/gjmas.v8i1.50812","url":null,"abstract":"This paper, which is on the problems of PPS sampling in multi-character surveys, compares the efficiency of some estimators used in PPSWR sampling for multiple characteristics. From a superpopulation model, we computed the expected variances of the different estimators for each of the first two finite populations considered, as well as the exact bias and variance of each of these estimators. The results obtained show that the estimators proposed by Rao (1966), Amahia et. al. (1989) and the alternative in Amahia et. al. (1989) are better than the conventional estimator. In population I, where the study variable and the ancillary variable are highly and positively correlated, results show that the estimator in Amahia et. al. (1989) fare better than the alternative estimator. On the other hand, the results obtained from our population II where the correlation between the study variable and the ancillary variable is poor, reveal that the alternative estimator in Amahia et. al. (1989) is more efficient. Several other finite populations whose ρare neither too high as in population I nor too poor as in population II were considered and it was discovered that the competition for efficiency only rests with the two estimators suggested by Amahia et al (1989) and Rao (1966). These interesting comparative results are shown in Tables.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"6 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120866323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
An optimal promotion cost control model for a markovian manpower system 马氏人力系统的最优促销成本控制模型
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/GJMAS.V8I1.50807
A. Udom, P. Uche
{"title":"An optimal promotion cost control model for a markovian manpower system","authors":"A. Udom, P. Uche","doi":"10.4314/GJMAS.V8I1.50807","DOIUrl":"https://doi.org/10.4314/GJMAS.V8I1.50807","url":null,"abstract":"A theory concerning the existence of an optimal promotion control strategy for controlling a Markovian manpower system is developed. Control interventions are made at controller’s specific time point with cost as an optimality performance criterion. A dynamic programming technique is adopted for the optimal solution and the model is applied to a hypothetical three-grade manpower system.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126547237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Bayesian analysis of right censored survival time data 右截尾生存时间数据的贝叶斯分析
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/gjmas.v8i1.50809
A. A. Abiodun
{"title":"Bayesian analysis of right censored survival time data","authors":"A. A. Abiodun","doi":"10.4314/gjmas.v8i1.50809","DOIUrl":"https://doi.org/10.4314/gjmas.v8i1.50809","url":null,"abstract":"We analyzed cancer data using Fully Bayesian inference approach based on Markov Chain Monte Carlo (MCMC) simulation technique which allows the estimation of very complex and realistic models. The results show that sex and age are significant risk factors for dying from some selected cancers. The risk of dying from these cancers is observed to progressively increase as age of patients increases. It is also observed that in order to allow for nonlinearity due to metrical covariate age, the semiparametric P-splines model is better than the model that categorizes age into various age groups.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125533130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Automating the management of software projects in a developing it economy 在发展中的it经济中自动化软件项目的管理
Global Journal of Mathematical Sciences Pub Date : 2010-02-09 DOI: 10.4314/GJMAS.V8I1.50814
I. Arikpo, A. Osofisan
{"title":"Automating the management of software projects in a developing it economy","authors":"I. Arikpo, A. Osofisan","doi":"10.4314/GJMAS.V8I1.50814","DOIUrl":"https://doi.org/10.4314/GJMAS.V8I1.50814","url":null,"abstract":"Software project management is the control of the transformation of users’ requirements and resources into a successful software result (product). This work automates the management of software projects in an emerging IT economy like Nigeria. It also explores the simulation of management practices such as configuration management and risk management. The COCOMO II model was employed for the estimation process, while the Risk Model from The American Systems Corporation (ASC) was used for risk management. Experimental data was obtained from AcadSoft Solutions, Calabar, Unical Computer Centre, and OmegaBiz.ng Software Solutions & Consultancy, Calabar. The resultant network-based software tool was developed on object-oriented technology using Java. The study established that good management practices may still be applied by the Nigerian software industry that lacks expertise in software management. Multi-site development approach facilitates large projects by using simple network-based application that aids collaboration among team members. Future research could extend to system and real-time software projects, to give a holistic picture of software project management in developing countries.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122951115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Probit regression in prediction analysis 预测分析中的概率回归
Global Journal of Mathematical Sciences Pub Date : 2009-12-03 DOI: 10.4314/gjmas.v8i2.53754
M. E. Nja
{"title":"Probit regression in prediction analysis","authors":"M. E. Nja","doi":"10.4314/gjmas.v8i2.53754","DOIUrl":"https://doi.org/10.4314/gjmas.v8i2.53754","url":null,"abstract":"To avoid diagnostic surgery, the probability of nodal involvement of prostate cancer is modeled using the probit link function to determine whether the lymph nodes of a patients are infected. X-ray status and level of acid phosphatase in the blood serum of patients are considered as preoperative explanatory variables with the number of patients having nodal involvement as response variable. Within the framework of the probit regression model, the level of nodal involvement is predicted and the probability of nodal involvement obtained.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114983307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pure diagonal bilinear moving average vector models 纯对角双线性移动平均向量模型
Global Journal of Mathematical Sciences Pub Date : 2009-08-19 DOI: 10.4314/GJMAS.V7I2.45195
A. Usoro, C. Omekara
{"title":"Pure diagonal bilinear moving average vector models","authors":"A. Usoro, C. Omekara","doi":"10.4314/GJMAS.V7I2.45195","DOIUrl":"https://doi.org/10.4314/GJMAS.V7I2.45195","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132305557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Modelling flow with hydraulic jump in a parabolic channel with abrupt change in slope 具有陡变坡度的抛物沟道中有水力跃变的流动模型
Global Journal of Mathematical Sciences Pub Date : 2009-08-19 DOI: 10.4314/GJMAS.V7I2.45181
A. Eyo
{"title":"Modelling flow with hydraulic jump in a parabolic channel with abrupt change in slope","authors":"A. Eyo","doi":"10.4314/GJMAS.V7I2.45181","DOIUrl":"https://doi.org/10.4314/GJMAS.V7I2.45181","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"380 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124734617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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