INTERNATIONAL JOURNAL OF INDUSTRIAL MATHEMATICS
Year:2018 | Volume:10 | Issue:3|Papers Count:8

Unsteady flow of gas through a porous medium is a strongly nonlinear ordinary differential equation on semi-infinite interval. In this paper, we have applied the pseudo-spectral collocation method with a positive scaling factor to solve unsteady flow of gas through a porous medium. The method reduces the solution of this problem to the solution of a system of nonlinear algebraic equations. The arising system is solved by Newton's method. To confirm the accuracy and efficiency of the presented scheme, we are compared the obtained numerical results with some well-known results. Results showed a very good agreement between results of presented scheme and the numerical solutions.

In this paper, while data envelopment analysis (DEA) technique has been used, four-stage DEA model mooted in order to consider the situation in which there exist returned products. These products are neither final products nor inputs of the next sub-process. These returned products are the inputs of previous sub-processes that need to be processed again due to existence of flaws. Here a supply chain with four stages as supplier, manufacture, distributor and retailer with intermediate and return products has been considered and a DEA model formulated for analyzing it. Also, with an application validity of the proposed model has been demonstrated.

In [1], the authors claimed by a counterexample that the cross product definition in [2] is not correct and thus the proposed technique is false. In this note, we show that this assertion is ‎incorrect.

With a brief review of the studies on the industry in Data Envelopment Analysis (DEA) framework, the present paper proposes inner and outer technologies when only some basic information is available about the technology. Furthermore, applying Linear Programming techniques, it also determines lower and upper bounds for directional distance function (DDF) measure, overall and allocative efficiency in industry level. Finally, the results are illustrated using a Cobb-Douglas function.

This study aims to discuss the use of robustness analysis in evaluation and selection the strategies of an organization based on a matrix approach. The proposed technique can overcome the weakness of the robustness analysis model related to reviewing a few future scenarios and also, makes it possible to in a short time include the ideas of the decision makers who participate in the strategic planning process. In order to more precisely compare the strategies, especially when their robustness levels are so close and consequently, it is hard to choose the best one, a version of the well-known Dolan-More performance profile is employed. To support the theoretical discussions, the proposed approach is applied on a real world problem in the automotive industry of Iran and the results are explained as well.

In this paper, a procedure is reported that discuss how linear algebra can be used in image compression. The basic idea is that each image can be represented as a matrix. We apply linear algebra (QR ‎factorization and wavelet ‎transformation ‎algorithm‏s) on this matrix and get a reduced matrix out such that the image corresponding to this reduced matrix requires much less storage space than the original image.

In wireless sensor and actor networks, connectivity among actors is very important, especially in critical applications where actors collaborate with each other to provide a report as soon as possible. Sometimes a node failure divides the given network into several parts; causing loss of connectivity between actors hence degrades the network performance. Several algorithms have been proposed to restore inter-actor connectivity. In these methods, selecting appropriate failure handler to minimize the relocations is crucial. In this paper the issue of finding the best backup is supposed the same as finding shortest path in stochastic graph problem. Owing that the solving stochastic shortest path is NP-complete, DLA is used for failure handler choice. This essay also presents a hybrid algorithm named DLA-BuS for critical node Back Up Selection based on distributed learning automata. Here two methods are proposed; first one is that each actor node is equipped with a learning automaton so that their cooperation in learning process leads to select the desired backups. The second method states the presentation of DLA-MRF to repair stimulant failure of two adjacent actors. In order to show the performance of the proposed algorithms extensive simulations using Castalia simulator have been conducted. Simulation results demonstrate that the mentioned proposed algorithms outperform existing methods in terms of the number of nodes movement, total distance travels, the percentage of coverage reduction, and energy consumption.

The aim of the present research is to analyze, comparatively, the content of mathematics textbooks in the first grade used in Iran, Japan, and the United States, which has three analytic axes, namely: teaching and learning opportunities based on process and content standards of NCTM, assessment and practice opportunities and content treatment according to five grade coding (narrative expressions, mathematical expressions, pictures, shapes, tables and diagrams). The statistical population of this query was the content of mathematics textbooks in the first grade used in Iran (both old version and the recent one), Japan, and the United States (California State). This research was conducted based on comparative content analysis method in which qualitative and quantitative analyses were used for data collection and data analysis, respectively. The results showed that in all content standards, except for measurement standard and statistics, the percentage of standards in the recent version of textbook used in Iran have been reduced practice standards, the recent version of math textbook used in Iran showed a significant increase in the treatment of connection standard as compared to that of its old version. According to the research findings, reasoning and proof standard was not treated in Japanes textbook as well as in the old and recent versions of textbooks used in Iran. Analysis of exercise and evaluation opportunities in the recent version of the Iranian textbook revealed that there was not any use of true-false questions. Therefore, the researcher’s recommendations based on their findings are: 1) more emphasis on using numeric and algebraic expressions in the treatment of concepts; 2) increasing, significantly, the treatment of reasoning and proof standard; 3) using truefalse questions in exercises and 4) using natural images in conceptualizations and transferring cultural contents.