Global Journal of Mathematical Sciences最新文献

{"title":"Application Of Shared Gamma And Inverse-Gaussian Frailty Models To Cancer Data","authors":"A. A. Abiodun","doi":"10.4314/GJMAS.V7I1.21426","DOIUrl":"https://doi.org/10.4314/GJMAS.V7I1.21426","url":null,"abstract":"Shared Gamma and Inverse-Gaussian Frailty models are used to analyze the survival times of patients who are clustered according to cancer/tumor types under Parametric Proportional Hazard framework. The result of the analysis shows that patients within the same cluster share some common unobserved heterogeneity which proves the analysis of such data under the assumption of independence inappropriate. This is an indication that conclusion based only on the observed covariates, ignoring the characteristic unobservable covariates in the data can be misleading. However, no evidence is strong enough for preference of either Gamma or Inverse Gaussian Frailty. Keywords : Failure time, Shared Frailty, Baseline hazard. Global Journal of Mathematical Sciences Vol. 7 (1) 2008: pp. 35-48","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127074718","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}

{"title":"On Total Variation Method For Digital Image Enhancement, Denoising And Deblurring","authors":"Ln Ezeako","doi":"10.4314/GJMAS.V7I1.21429","DOIUrl":"https://doi.org/10.4314/GJMAS.V7I1.21429","url":null,"abstract":"In this paper, we define the necessity for recourse to Total Variation method in digital image filtering and we establish the existence of a refined image in the space of Bounded Variation Functions BV(Ω), for a given “screen” Ω. Keywords : Image (signal), Vibration (Noise), Total Variation, Functions with Bounded Variation Global Journal of Mathematical Sciences Vol. 7 (1) 2008: pp. 57-62","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"190 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116517083","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}

{"title":"Analysing Stagecoach Network Problem Using Dynamic Programming Algorithm","authors":"P. Ekoko","doi":"10.4314/gjmas.v7i1.21423","DOIUrl":"https://doi.org/10.4314/gjmas.v7i1.21423","url":null,"abstract":"The stagecoach problem is a special type of network analysis problem in which the cities (nodes) are arranged in stages. By such human or natural arrangement, a journey from City 1 in stage 1 to City n in stage n involves visiting only one city in each intermediate stage. The stagecoach problem involves the determination of the minimum cost flow in which basically two methods have been in use. One of the methods is by listing all possible routes, computing their corresponding costs and selecting the minimum cost route. This procedure entails much computational effort. The second procedure is to determine the suboptimal cost of routes between any two consecutive stages. Though this second approach has less computational effort, its overall optimal policy could be wrong because the choice of a least expensive route at one stage may result in our adopting a more expensive route at a later stage. In this paper we present a recursive dynamic programming algorithm for solving the stagecoach problem. The algorithm is computationally more efficient than the first method as it obtains its minimum total cost using the suboptimal policies of the different stages without computing the cost of all the routes. By the dynamic programming algorithm of this paper, the possibility of missing the minimum cost route is ruled out as could happen in the second approach. The dynamic programming algorithm for obtaining the minimum cost path in a stagecoach problem is numerically illustrated Keywords : Network analysis, stagecoach, dynamic programming algorithm Global Journal of Mathematical Sciences Vol. 7 (1) 2008: pp. 15-20","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125624825","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}

{"title":"Numerical Algorithm For Digital Image Enhancement And Noise Minimization","authors":"Ln Ezeako, K. Adeboye","doi":"10.4314/gjmas.v7i1.21430","DOIUrl":"https://doi.org/10.4314/gjmas.v7i1.21430","url":null,"abstract":"We adopt the approach of Vogel and Oman, 1998 and introduce a Lagrange multiplier Ibiejugba, 1985, to obtain an appropriate discrete energy which we minimize, in order to minimize equivalently, the unwanted vibration (noise) associated with a digitally transmitted image. An iterative algorithm is developed for this minimization and the convergence of the algorithm is proved analytically. Keywords : Digital Image Enhancement, Noise Minimisation Global Journal of Mathematical Sciences Vol. 7 (1) 2008: pp. 63-68","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129343916","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}

{"title":"Cyclical subnormal separated A-groups of nilpotent length four","authors":"Um Makarfi","doi":"10.4314/GJMAS.V5I1.21380","DOIUrl":"https://doi.org/10.4314/GJMAS.V5I1.21380","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131114851","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}

{"title":"Cyclical subnormal separation in A-groups","authors":"Um Makarfi","doi":"10.4314/GJMAS.V5I1.21379","DOIUrl":"https://doi.org/10.4314/GJMAS.V5I1.21379","url":null,"abstract":"Three main results, concerning ,4-groups in respect of cyclical subnormal separation as defined in [4], are presented. It is shown in theorem A that any /1-group that, is generated by elements of prime order and satisfying the cyclical subnormal separation condition is metabelian. The two other main results give necessary and sufficient conditions for r4-groups, that are split extensions of certain abclian p-groups by a metabelian p' group, to satisfy the cyclical subnormal separation condition. There is also a result which shows that .4-groups with elementary abelian Sylow subgroups are cyclically separated as defined in [3]. 1-. Introduction A group G is called a CSn group if for any given cyclic subgroup B '„ group if and only if every element of // of prime order is in the Fitting subgroup of H. Theorem C Suppose that G = W » H is an /1-group where W is a minimal normal subgroup of G and // is a metabelian /)'-subgroup acting faithfully on W. Then G is a CSn group if and only if every elementof HF(H) acts fixed-point-freely on 14-', where F(!l) is the Kitting subgroup of H. We also come across this result, Lemma (3.3) which concerns CS groups. We find it appropriate to bring it here because the CSpaper introduced in [3] was the motivating factor for the appearance of the CSn groups. There was the general feeling that /l-groups may be C.^-groups. Lemma (3.3) gave one positive result. But as it turns out we have an example of an A group which is even a CS7I group but not a CS-group. Section 2 deals with general results that are of interest to us including an example of a rion metabelian ,4-group in CSn. In fact as it has been pointed out in the concluding remarks ,i slight modification of this example gives an example of an /1-group in CSn which i> not a CS group. MIRAMARE TRIESTE December 1995 'Permanent address: Department of Mathematics, Ahrnadu Bello University, Samaru, Zaria, Kaduna State, Nigeria. 2 Preliminaries 2.1 Theorem A established that any A-group in CSn which is generated by elements of prime order must be metabelian. We begin our discussions with an example to show, first, that there are non metabelian /l-groups in CSn and secondly that the hypothesis, in the theorem, of the generating elements to be of prime order is necessary. We note that metabelian groups had already been shown to belong to the class of CSn groups [(3.5) of [4]]2.2 Example (2.2) Suppose that p, q and r are three distinct primes and (i) is a cyclic group of order r. Let k be the order of q mod r, i.e., r ^ j and r f IJ' — 1 for ( '') = 1Tliis implies that C'JX'O — 1. Clearly, O is an .4 group. To see why it is a f-'.S',, group we first observe tiiat C = L » H where II = M{.r) is a ;/-metabelian group, by [(3.!)) [4]] // G Ci>'n. Nest, any (; eleinent in // is conjugate to some m € M arid by n)\" denotes the smallest subnormal subgroup of // containing in. Note that. (m) \" = (m) since A/ is abelian and normal in //. Also, any r element of // is conjugate to an ","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131268144","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}

{"title":"Application of Markovian model to school enrolment projection process","authors":"V. Ekhosuehi, A. Osagiede","doi":"10.4314/GJMAS.V5I1.21375","DOIUrl":"https://doi.org/10.4314/GJMAS.V5I1.21375","url":null,"abstract":"This paper deals with the application of Markov chain model to student's enrolment projectioli in a u~iversity in Nigeria. Specifically, the paper contains the estimation of the constant rate of increase in the number of new intake into a programme of study. The estimators proposed by previous authors are used for the estimation and subsequently, the enrolment projection.","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129745468","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}

{"title":"Mathematical model on the blood glucose/insulin concentrations in an insulin-dependent diabetic patient: case of a patient with variable pancreatic insulin release","authors":"G. Mbah","doi":"10.4314/gjmas.v5i1.21384","DOIUrl":"https://doi.org/10.4314/gjmas.v5i1.21384","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128939299","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}

{"title":"Estimation of the microfilaria load in a host using the microfilaria count in a skin-snip sample taken from any other part of the body of the host below illiac crest","authors":"G. Mbah","doi":"10.4314/GJMAS.V6I2.21420","DOIUrl":"https://doi.org/10.4314/GJMAS.V6I2.21420","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121165818","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}

{"title":"Monolithic A-groups in CS n","authors":"Um Makarfi","doi":"10.4314/GJMAS.V5I1.21378","DOIUrl":"https://doi.org/10.4314/GJMAS.V5I1.21378","url":null,"abstract":"","PeriodicalId":126381,"journal":{"name":"Global Journal of Mathematical Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131368986","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}