Open Access Method Article

Subset Sarima Modelling: An Alternative Definition and a Case Study

Ette Harrison Etuk, Nathaniel Ojekudo

Journal of Advances in Mathematics and Computer Science, Page 538-552
DOI: 10.9734/BJMCS/2015/14305

Aims: To provide an alternative definition for subset Sarima modeling and demonstrate it by application to monthly internally generated revenue of Ikot Ekpene Local Government Area of Akwa Ibom State of Nigeria.
Study Design: The study design is theoretical as well as empirical.
Place and Duration of Study: Department of Mathematics and Computer Science, Rivers State University of Science and Technology, Port Harcourt, Nigeria.
Methodology: Based on the duality relationship between autoregressive (AR) and moving average (MA) models an alternative definition to subset sarima models is proposed. The seasonality of the above-mentioned time series is established. A non-seasonal differencing of the seasonal difference of the series yields a stationary series which is analysed by Sarima methods.
Results: Applying the duality relationship between AR and MA models, subset Sarima models may be defined in AR terms rather than exclusively in MA terms as earlier done. An analysis of a 120-point internally generated revenue series from 1998 to 2007 yields the additive model from the original SARIMA (1, 1, 0)x(1, 1, 0)12 model. The additive model is found to be adequate.
Conclusion: Based on the new and equivalent definition the monthly internally generated revenue of Ikot Ekpene Local Government Area of Nigeria follows an additive Sarima Model.

Open Access Original Research Article

Relaxing the Hypotheses of Symmetry and Time-Reversibility in Genome Evolutionary Models

Jacques M. Bahi, Christophe Guyeux, Antoine Perasso

Journal of Advances in Mathematics and Computer Science, Page 439-455
DOI: 10.9734/BJMCS/2015/14280

Various genome evolutionary models have been proposed these last decades to predict the evolution of a DNA sequence over time, essentially described using a mutation matrix. By essence, all of these models relate the evolution of DNA sequences to the computation of the successive powers of the mutation matrix. To make this computation possible, hypotheses are assumed for the matrix, such as symmetry and time-reversibility, which are not compatible with mutation rates that have been recently obtained experimentally on genes ura3 and can1 of the Yeast Saccharomyces cerevisiae. In this work, authors investigate systematically the possibility to relax either the symmetry or the time-reversibility hypothesis of the mutation matrix, by investigating all the possible matrices of size 2Χ2 and 3Χ3. As an application example, the experimental study on the Yeast Saccharomyces cerevisiae has been used in order to deduce a simple mutation matrix, and to compute the future evolution of the rate purine/pyrimidine for ura3 on the one hand, and of the particular behavior of cytosines and thymines compared to purines on the other hand.

Open Access Original Research Article

Similarity-Based Content Retrieval in Self-Organizing Peer-to-Peer Networks

Takuya Yamaguchi, Andrii Zhygmanovskyi, Noriko Matsumoto, Norihiko Yoshida

Journal of Advances in Mathematics and Computer Science, Page 456-470
DOI: 10.9734/BJMCS/2015/14177

This paper presents dynamic reorganization of peer-to-peer networks to make query routing and content retrieval efficient. The reorganization is conducted which use content similarity information. Unlike other related studies using semantic proximity, the method proposed in this paper relies on folksonomy, which gained wide use in figuring out content similarity in various social networks. The proposed method is designed primarily for flooding-based unstructured P2P networks, however it also can be applied to structured P2P networks such as Tapestry. Simulation-based experiments confirm the effectiveness of the proposed method.

Open Access Original Research Article

Existence of Coupled Quasi-solutions of Nonlinear Integro-Differential Equations of Volterra Type in Banach Spaces

Yan Liang

Journal of Advances in Mathematics and Computer Science, Page 471-478
DOI: 10.9734/BJMCS/2015/13726

We study an initial value problem for a class of integro-differential equations of Volterra type in a real Banach space. Using method of upper and lower solutions and M¨onch and Von Harten theorem, we obtain an existence theorem of coupled quasi-solutions, which is an extension of those established by Y. Chen and W. Zhuang in [1].

Open Access Original Research Article

On Some New Nonlinear Retarded Integral Inequalities with Iterated Integrals and their Applications in Integro-Differential Equations

A. Abdeldaim, A. A. El-Deeb

Journal of Advances in Mathematics and Computer Science, Page 479-491
DOI: 10.9734/BJMCS/2015/13866

In this paper, some new generalized retarded nonlinear integral inequalities of Gronwall-Bellman type are discussed. The upper bounds estimation of the embedded unknown functions are discussed by integral and differential techniques. Our results generalize some inequalities of H. El-Owaidy et al. [1] with both retard and nonlinear integral. Some applications are also presented in order to illustrate the usefulness of some of our results.

Open Access Original Research Article

Existence of Nonoscillatory Solutions of Higher Order Forced Neutral Dynamic Equations with Time Delay on Time Scales

Jinjun Fan, Xiaodong Lu

Journal of Advances in Mathematics and Computer Science, Page 492-501
DOI: 10.9734/BJMCS/2015/14006

The existence of nonoscillatory solutions of a class of higher order forced neutral dynamic equations with time delay on time scales is discussed. The main tool is the Banach fixed point theorem. Based on the different values of p(t), we give several existence theorems of nonoscillatory solutions of our discussing equations. An example is also presented to illustrate the applications of the obtained results.

Open Access Original Research Article

Forecasting the Yield of Academic Software Investments in Nigerian Universities

Abejide Ade-Ibijola, Elizabeth Y. Ibijola, Babakemi Ade-Ibijola

Journal of Advances in Mathematics and Computer Science, Page 502-514
DOI: 10.9734/BJMCS/2015/13066

This paper presents a mathematical model (with computer simulation) for forecasting the profits of buying software for the automation of established processes in the Nigerian University System. The mathematical model uses certain assumptions to provide a basis for iterative estimation of future income and the obtained results are intended to assist the management and stakeholders in deciding if investing in a software project is worthwhile.

Open Access Original Research Article

Controlled Variational Iteration Method for Bratu Equation Arising in Electro-Spun Organic Nanofibers Elaboration

Mohamed M. Mousa

Journal of Advances in Mathematics and Computer Science, Page 515-524
DOI: 10.9734/BJMCS/2015/14237

In this paper, an effective formulation of the variational iteration method is suggested for solving Bratu equation arising in electro-spinning. The suggested formulation depends on embedding a nonzero auxiliary parameter that controls the solution convergence region. An alternative formulation of the Bratu equation is suggested as well. The proposed formula eliminates the complexity that appears when solving using the standard variational iteration algorithms illustrated in [1,2] without approximating the exponential term. A suitable choice of the auxiliary parameter results in an accurate approximation compared with the approximation of the standard variational iteration method.

Open Access Original Research Article

Improved Power System State Estimation by Selected Node Technique

H. Nagaraja Udupa, H. Ravishankar Kamath

Journal of Advances in Mathematics and Computer Science, Page 525-537
DOI: 10.9734/BJMCS/2015/13435

The state estimator is integral part of any Energy Management System. First and foremost the state estimation must be executed followed by system control, tie-line control, economic dispatch, security analysis etc. Most importantly the system voltage controls and the tie-line power controls must be handled within milliseconds to a few seconds. Obviously, in order to meet the requirements, state estimator should be able to process the results very fast. Due to the kind of complexity associated with the power system it’s very difficult to carry out the estimation in very short time. The author, H.N. Udupa & Dr. H.R. Kamath [1,2] had suggested a new innovative method to solve this complex problem in desired time without compromising on the results accuracy. In the said new approach, State Estimations are computed at each Node level.
This paper presents a unique technique to carried-out the State Estimation at selected Node Areas instead of every Node Area. As the network is interconnected, by selecting suitable Node Area it is possible to estimate all the state variables of the system. The method of selecting the Node Area is detailed in this paper. A node/bus along with its connected nodes/buses is called “Node Area”. By computing the SE only at Selected Nodes reduces the complexity of the system and also results in huge cost saving. The Node Area level of state estimation technique is suitable for smart grid application. This paper presents the Node Area selection technique along with its computational time and comparison with the conventional Integrated State Estimation (ISE) and Node Level State estimation.`

Open Access Review Article

Positive Radial Solutions of the p-Laplacian in an Annulus with a Superlinear Nonlinearity with Zeros

Xiaomin Liu, Zuodong Yang

Journal of Advances in Mathematics and Computer Science, Page 429-438
DOI: 10.9734/BJMCS/2015/13254

In this paper, we study existence, and the asymptotic behavior, with respect to λ , of positive radially symmetric solutions of

                                                                                −ΔΡu = λh(xu)

in annular domains in RN;N ≥ 2. The nonlinear term has a superlinear local growth at infinity, and is nonnegative.