International Journal of Computer Mathematics (INT J COMPUT MATH)
Journal description
Section A: Computer Systems: Programming Languages. This section contains work concerning research and development in computer systems and the theory of programming languages. Papers relating directly or indirectly to aspects of these fields are welcome. Of great interest is work in computer systems architectures and organisation, computer software and data structures, mathematical logic, formal languages, automata, artificial intelligence, parallelism and concurrency, analysis of algorithms, computational complexity, combinatorial algorithms, and symbol manipulation. The journal is intended to provide a forum for the expression of new ideas, as well as a place for exposition of these areas of knowledge. Section B: Computational Methods: Application. This section contains work concerning mathematical techniques that are of interest to computer users in the fields of numerical analysis, mathematical software, discrete mathematics, computational geometry and graphics, image processing, pattern recognition, simulation and modelling, operations research and applied mathematics in general.
Current impact factor: 0.72
Impact Factor Rankings
2015 Impact Factor  Available summer 2015 

2013 / 2014 Impact Factor  0.721 
2012 Impact Factor  0.542 
2011 Impact Factor  0.499 
2010 Impact Factor  0.489 
2009 Impact Factor  0.478 
2008 Impact Factor  0.308 
2007 Impact Factor  0.423 
2006 Impact Factor  0.428 
2005 Impact Factor  0.254 
2004 Impact Factor  0.216 
2003 Impact Factor  0.226 
2002 Impact Factor  0.139 
2001 Impact Factor  0.162 
2000 Impact Factor  0.121 
1999 Impact Factor  0.133 
1998 Impact Factor  0.145 
1997 Impact Factor  0.18 
1996 Impact Factor  0.18 
1995 Impact Factor  0.092 
1994 Impact Factor  0.126 
1993 Impact Factor  0.192 
1992 Impact Factor  0.22 
Impact factor over time
Additional details
5year impact  0.56 

Cited halflife  5.00 
Immediacy index  0.37 
Eigenfactor  0.00 
Article influence  0.23 
Website  International Journal of Computer Mathematics website 
Other titles  International journal of computer mathematics (Online) 
ISSN  00207160 
OCLC  50166329 
Material type  Document, Periodical, Internet resource 
Document type  Internet Resource, Computer File, Journal / Magazine / Newspaper 
Publisher details

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 Publisher's version/PDF cannot be used
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 Must link to publisher version
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 The publisher will deposit in on behalf of authors to a designated institutional repository including PubMed Central, where a deposit agreement exists with the repository
 STM: Science, Technology and Medicine
 Publisher last contacted on 25/03/2014
 This policy is an exception to the default policies of 'Taylor & Francis'

Classification green
Publications in this journal

Article: Improving Performance for Task Assignement in Distributed Server Systems by Partitioning Large Tasks
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ABSTRACT: Task Assignment in distributed server systems focuses on the policy that assigns the tasks reached these systems in order to improve the response time. These tasks, generally, have the property that there is a tiny fraction (about 3%) of the large tasks that makes half (50%) of the total load. However, this property creates additional problems: the large tasks make the load difficult to balance among the servers, and the small tasks will be delayed by the large ones when they are in the same queue. In this paper, we propose a new policy for the Web clusters that we call Partitioning Large Tasks (PLT) and which deals with these problems mostly under a high traffic demand and a high variability of task sizes. PLT partitions each large task into fragments and assigns them to be processed in a parallel way and completing at the same time to improve the mean response time, and separates the small tasks from the large tasks to avoid being delayed. Performance tests show a significantly improvement in performance of PLT over the existing task assignment policies.International Journal of Computer Mathematics 09/2015; 92(2):250265. DOI:10.1080/00207160.2014.901660 
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ABSTRACT: In this paper we discuss a local radial basis functionbased finite difference (RBFFD) scheme for numerical solution of multiasset American option problems. The governing equation is discretized by the method and the option price is approximated by the RBFFD method. Numerical experiments are performed with the multiquadratic radial basis function for single and double asset problem and results obtained are compared with existing ones. We show numerically that the scheme is secondorder accurate. Stability of the scheme is also discussed.International Journal of Computer Mathematics 08/2015; 92(8). DOI:10.1080/00207160.2014.950571 
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ABSTRACT: In this paper, we consider the problem of capacitated covering with unit balls. In this problem, a set of weighted points in a metric space is given, and we want to cover them with a minimum number of the unit balls of that metric space provided that the total weight assigned to each unit ball is at most one. The problem is NPhard as it generalizes the coveringwithunitballs problem. We consider the problem in two cases: (1) the weight of each point can be split among several unit balls and (2) the unsplittable case. In the latter case, the problem is a generalization of the binpacking problem even when , and thus it is not approximable under 1.5, unless P=NP. We design a polynomialtime approximation scheme (PTAS) for the splittable case when is a fixed constant and is an metric. This also results in a PTAS for the unsplittable case when all the points have the same weight. We also analyse several natural algorithms for this problem and prove that they achieve constant approximation factors.International Journal of Computer Mathematics 08/2015; 92(8). DOI:10.1080/00207160.2014.959506 
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ABSTRACT: In this paper, a computational method for numerical solution of a class of integrodifferential equations with a weakly singular kernel of fractional order which is based on Cos and Sin (CAS) wavelets and block pulse functions is introduced. Approximation of the arbitrary order weakly singular integral is also obtained. The fractional integrodifferential equations with weakly singular kernel are transformed into a system of algebraic equations by using the operational matrix of fractional integration of CAS wavelets. The error analysis of CAS wavelets is given. Finally, the results of some numerical examples support the validity and applicability of the approach.International Journal of Computer Mathematics 08/2015; 92(8). DOI:10.1080/00207160.2014.964692 
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ABSTRACT: In this paper, an affinescaling derivativefree trustregion method with interior backtracking line search technique is considered for solving nonlinear systems subject to linear inequality constraints. The proposed algorithm is designed to take advantage of the problem structured by building polynomial interpolation models for each function in the nonlinear system function F. The proposed approach is developed by forming a quadratic model with an appropriate quadratic function and scaling matrix: there is no need to handle the constraints explicitly. By using both trustregion strategy and interior backing line search technique, each iteration switches to backtracking step generated by the trustregion subproblem and satisfies strict interior point feasibility by line search backtracking technique. Under reasonable conditions, the global convergence and fast local convergence rate of the proposed algorithm are established. The results of numerical experiments are reported to show the effectiveness of the proposed algorithms.International Journal of Computer Mathematics 08/2015; 92(8). DOI:10.1080/00207160.2014.959942 
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ABSTRACT: Rotation symmetric Boolean functions have been extensively studied for about 15 years because of their applications in cryptography and coding theory. Until recently little was known about the basic question of when two such functions are affine equivalent. The simplest case of quadratic rotation symmetric functions which are generated by cyclic permutations of the variables in a single monomial was only settled in 2009. For the much more complicated case of cubic rotation symmetric functions generated by a single monomial, the affine equivalence classes under permutations which preserve rotation symmetry were determined in 2011. It was conjectured then that the cubic equivalence classes are the same if all nonsingular affine transformations, not just permutations, are allowed. This conjecture is probably difficult, but here we take a step towards it by proving that the cubic affine equivalence classes found in 2011 are the same if all permutations, not just those preserving rotation symmetry, are allowed. The needed new idea uses the theory of circulant matrices.International Journal of Computer Mathematics 08/2015; 92(8). DOI:10.1080/00207160.2014.964693 
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ABSTRACT: Burgers’ equation can model several physical phenomena. In the first part of this work, we derive a threelevel linearized difference scheme for Burgers’ equation, which is then proved to be energy conservative, unique solvable and unconditionally convergent in the maximum norm by the energy method combining with the inductive method. In the second part of the work, we prove the L ∞ unconditional convergence of a twolevel linearized difference scheme for Burgers’ equation proposed by Sheng [A new difference scheme for Burgers equation, J. Jiangsu Normal Univ. 30 (2012), pp. 39–43], which was proved previously conditionally convergent.International Journal of Computer Mathematics 06/2015; 92(6). DOI:10.1080/00207160.2014.927059 
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ABSTRACT: In this paper, we propose a new reformulation for stochastic complementarity problems (SCP). The new formulation is based on the minimum mean squared deviation (MMSD) rule in statistics. Under mild conditions, we prove the existence of the solution of the new reformulation for SCP. Furthermore, we present a smoothing sample average approximation (SAA) method for solving the problems. The convergence properties of the optimal solutions of the approximation problems is studied under mild conditions. Finally, some numerical results are listed as well.International Journal of Computer Mathematics 04/2015; DOI:10.1080/00207160.2015.1040400 
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ABSTRACT: An efficient identitybased encrypion (IBE) scheme over lattice is proposed in this paper. Under the hardness of the learning with errors problem (LWE), the proposed scheme is semantic secure against adaptive chosen identity and chosen plaintext attack in the standard model. To improve the efficiency of the latticebased IBE scheme, unlike the identity string is encoded into a matrix by a group of public matrices in several known constructions, the identity string of l bits is encoded into a vector with the help of l+1 vectors in this paper. With the help of this idea, we achieve the private key extraction of IBE scheme at the same lattice. Then, the public key of the proposed scheme only consists as one n×m matrix and l+1 vectors, compared with that the public keys of the known latticebased IBE schemes all consist as a group of n×m matrices. Hence the public key size of this scheme is shorter than that of the known constructions.International Journal of Computer Mathematics 04/2015; DOI:10.1080/00207160.2015.1029464 
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ABSTRACT: We describe multiparameter continuation methods combined with spectral collocation methods for computing numerical solutions of rotating twocomponent Bose–Einstein condensates (BECs), which are governed by the Gross–Pitaevskii equations (GPEs). Various types of orthogonal polynomials are used as the basis functions for the trial function space. A novel multiparameter/multiscale continuation algorithm is proposed for computing the solutions of the governing GPEs, where the chemical potential of each component and angular velocity are treated as the continuation parameters simultaneously. The proposed algorithm can effectively compute numerical solutions with abundant physical phenomena. Numerical results on rotating twocomponent BECs are reported.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.915959 
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ABSTRACT: Let G=(V, E) be a simple graph with vertex set V and edge set E. A signed mixed dominating function (SMDF) of G is a function f: V∪E→{−1, 1} such that for every element x∈V∪E, where N m (x) is the set, called mixed neighbourhood of x, of elements of V∪E adjacent or incident to x. In other words, for every listassignment of two colours {−1, 1} to every elements of V∪E, there is a listcolouring of vertices and edges of G such that all mixed neighbourhoods contain more 1′s than−1′s. The weight of f is w(f)=∑x∈V∪E f(x). The signed mixed domination number γs *(G) of G is the minimum weight of all possible SMDF of G. In this paper, we determine the exact value of the signed mixed domination number in a complete bipartite graph.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.920832 
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ABSTRACT: A local colouring of a graph G is a function c: V(G)→ such that for each S ⊆ V(G), 2≤S≤3, there exist u, v∈S with c(u)−c(V) at least the number of edges in the subgraph induced by S. The maximum colour assigned by c is the value χl(c) of c, and the local chromatic number of G is χl(G)=min {χl(c): c is a local colouring of G}. In this note the local chromatic number is determined for Cartesian products G □ H, where G and GH are 3colourable graphs. This result in part corrects an error from Omoomi and Pourmiri [On the local colourings of graphs, Ars Combin. 86 (2008), pp. 147–159]. It is also proved that if G and H are graphs such that χ(G)≤⌊ χl(H)/2 ⌋, then χl(G □ H)≤χl(H)+1.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.918609 
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ABSTRACT: In this paper, homotopy perturbation method (HPM) and variational iteration method (VIM) are used to solve the large amplitude torsional oscillations equations in a nonlinearly suspension bridge. This paper compares the HPM and VIM in order to solve the equations of nonlinearly suspension bridge. A comparative study between the HPM and VIM is presented in this work. The achieved results reveal that the HPM and VIM are very effective, convenient and quite accurate to nonlinear partial differential equations. These methods can be easily extended to other strongly nonlinear oscillations and can be found widely applicable in engineering and science. The Laplace transform method is applied to obtaining the Lagrange multiplier in the VIM solution.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.909929 
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ABSTRACT: The two important qualities of a cipher are security and speed. Frequently, to satisfy the security of a Boolean function primitive, speed may be tradedoff. In this paper, we present a general construction that addresses both qualities. The idea of our construction is to manipulate a cryptographically strong base function and one of its affine equivalent functions, using concatenation and negation. We achieve security from the inherent qualities of the base function, which are preserved (or increased), and obtain speed by the simple Boolean operations. We present two applications of the construction to demonstrate the flexibility and efficiency of the construction.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.920085 
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ABSTRACT: This paper is concerned with numerical stability of general linear methods (GLMs) for a system of linear neutral delay differentialalgebraic equations. A sufficient and necessary condition for asymptotic stability of GLMs solving such system is derived. Based on this main result, we further investigate the asymptotic stability of linear multistep methods, Runge–Kutta methods, and block methods, respectively. Numerical experiments confirm our theoretical result.International Journal of Computer Mathematics 04/2015; 92(4). DOI:10.1080/00207160.2014.914178 
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ABSTRACT: In this paper, a second order backward differentiation formula (BDF) compact difference scheme with the truncation error of order 1 + α(0 < α < 1) for time and 4 for space to fractional order Volterra equations is considered. The integral term is treated by means of the second order convolution quadrature suggested by Lubich and fourthorder accuracy compact approximation is applied for the secondorder space derivative. The stability and convergence of the compact difference scheme in a new norm are proved by the energy method. Numerical experiments that are in total agreement with our analysis are reported.International Journal of Computer Mathematics 03/2015; DOI:10.1080/00207160.2015.1021695 
Article: A fourthorder partial differential equation denoising model with an adaptive relaxation method
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ABSTRACT: In this paper, an adaptive relaxation method and a discontinuity treatment of edges are proposed to improve the digital image denoising process by using the fourthorder partial differential equation (known as the YK model) first proposed by You and Kaveh. Since the YK model would generate some speckles into the denoised image, a relaxation method is incorporated into the model to reduce the formation of isolated speckles. An additional improvement is employed to handle the discontinuity on the edges of the image. In order to stop the iteration automatically, a control of the iteration is integrated into the denoising process. Numerical results demonstrate that such modifications not only make the denoised image look more natural, but also achieve a higher value of peak signal noise ratio (PSNR).International Journal of Computer Mathematics 03/2015; 92(3). DOI:10.1080/00207160.2014.904854 
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ABSTRACT: Two types of uncertainties are generally recognized in modelling and simulation, including variability caused by inherent randomness and incertitude due to the lack of perfect knowledge. In this paper, a generalized intervalprobability theory is used to model both uncertainty components simultaneously, where epistemic uncertainty is quantified by generalized interval in addition to probability measure. Conditioning, independence, and Markovian probabilities are uniquely defined in generalized interval probability such that its probabilistic calculus resembles that in the classical probability theory. A pathintegral approach can be taken to solve the interval Fokker–Planck equation for diffusion processes. A Krylov subspace projection method is proposed to solve the interval master equation for jump processes. Thus, the time evolution of both uncertainty components can be simulated simultaneously, which provides the lower and upper bound information of evolving probability distributions as an alternative to the traditional sensitivity analysis.International Journal of Computer Mathematics 03/2015; 92(3). DOI:10.1080/00207160.2014.905681 
Article: On dynamics of automata with a stack
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ABSTRACT: In this paper we introduce a new dynamical system of a pushdown automaton, called automaton with a stack (AS). We prove that every AS has a periodic configuration by construction of it. Next, we define a special case of an AS, called AS with finite memory and we prove that the AS has a finite memory if and only if it is positively expansive. Furthermore, we prove that every AS with finite memory has shadowing property. Having these two properties, we set a finitetoone map between an AS with finite memory and some vertex subshift, which gives us a semiconjugacy between these two systems. Additionally, we define an algorithm to decide if a given graph G describes some AS with finite memory and to calculate maximal depth of a stack.International Journal of Computer Mathematics 03/2015; 92(3). DOI:10.1080/00207160.2014.914508
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