An efficient iterated method for mathematical biology model

The purpose of this study is to introduce an efficient iterated homotopy perturbation transform method (IHPTM) for solving a mathematical model of HIV infection of CD4+ T cells. The equations are Laplace transformed, and the nonlinear terms are represented by He’s polynomials. The solutions are obtained in the form of rapidly convergent series with elegantly computable terms. This approach, in contrast to classical perturbation techniques, is valid even for systems without any small/large parameters and therefore can be applied more widely than traditional perturbation techniques, especially when there do not exist any small/large quantities. A good agreement of the novel method solution with the existing solutions is presented graphically and in tabulated forms to study the efficiency and accuracy of IHPTM. This study demonstrates the general validity and the great potential of the IHPTM for solving strongly nonlinear problems.     

Multi-product production quantity model with repair failure and partial backordering

In this paper, a production quantity model with random defective items, service level constraints and repair failure is studied. The existence of only one machine results in limited production capacity and partial backordering. The aim of this research is to determine the optimal cycle length, optimal production quantity and optimal backordered quantity of each product such that the expected total cost (holding, shortage, production, setup, defective items and repair costs) is minimized. Two numerical examples and sensitivity analysis are provided to illustrate the practical usage of the proposed method.     

Variational iteration method and homotopy perturbation method for fourth-order fractional integro-differential equations

In this article, linear and nonlinear boundary value problems for fourth-order fractional integro-differential equations are solved by variational iteration method and homotopy perturbation method. The fractional derivatives are described in the Caputo sense. The solutions of both problems are derived by infinite convergent series which are easily computable and then graphical representation shows that both methods are most effective and convenient one to solve linear and nonlinear boundary value problems for fourth-order fractional integro-differential equations.     

Application of psyllium husk as coagulant and coagulant aid in semi-aerobic landfill leachate treatment

Landfill leachate is a heavily polluted and a likely hazardous liquid that is produced as a result of water infiltration through solid wastes generated industrially and domestically. This study investigates the potential of using psyllium husk as coagulant and coagulant aid for the treatment of landfill leachate. Psyllium husk has been tested as primary coagulant and as coagulant aid with poly-aluminum chloride (PACl) and aluminum sulfate (alum). As primary coagulant, the optimum dosage and pH for PACl were 7.2 and 7.5 g/L, respectively, with removal efficiencies of 55, 80 and 95% for COD, color and TSS, respectively. For alum, the optimum conditions were 11 g/L alum dosage and pH 6.5 with removal efficiencies of 58, 79 and 78% for COD, color and TSS, respectively. The maximum removal efficiencies of COD, color and TSS were 64, 90 and 96%, respectively, when psyllium husk was used as coagulant aid with PACl. Based on the results, psyllium husk was found to be more effective as coagulant aid with PACl in the removal of COD, color and TSS as compared to alum. Zeta potential test was carried out for leachate, PACl, alum and psyllium husk before and after running the jar test to enhance the results of the jar test experiments.     

System identification in a networked environment using second order statistical properties

System identification for networked control is considered. Due to the time-delays in the network, it can be difficult to work with a discrete-time model and a continuous-time model is therefore chosen. A covariance function based method that relies on the second order statistical properties of the output signal, where it is assumed that the input signal samples are from a discrete-time white noise sequence, is proposed for estimating the parameters. The method is easy to use since the actual time instants when new input signal levels are applied at the actuator do not have to be known. An analysis of the networked system and the effects of the time-delays is made, and the results of the analysis motivate and support the chosen approach. Numerical studies indicate that the method is robust to randomly distributed time-delays, packet drop-outs, and additive measurement noise.     

A new method to explore the structure of effective dimensions for functions

Effective dimension, an indicator for the difficulty of high-dimensional integration, describes whether a function can be well approximated by low-dimensional terms or sums of low-order terms. Some problems in option pricing are believed to have low effective dimensions, which help explain the success of quasi-Monte Carlo (QMC) methods recently observed in financial engineering. This paper provides a way of studying the structure of effective dimensions by finding a proper space the function of interest belongs to and then determining the effective dimension of that space. To this end, we extend the definitions of effective dimensions to weighted function spaces with product-order-dependent weights and give bounds on norms and variances. Furthermore, we show that the proposed method is applicable to functions arising in option pricing and consequently offers some hints on the performance of QMC methods.

     

Preservation of mango juice by freezing and canning

In this work the preservation of mango juice by freezing and canning was compared. The following results were obtained: The loss of ascorbic acid during the preparation of canned mango juice is mainly due to the processing steps other than retorting which had the least harmful effect. The retention of ascorbic acid and carotene after canning and freezing was nearly the same. Both freezing and canning caused no marked changes in the pectin content. The inactivation of the pectin methylesterase was more obvious after canning than after freezing. Reducing sugars slightly increased after freezing and canning, while the acidity and pH showed no appreciable changes. The chemical constituents except the sugars of the commercial samples were lower than those of the experimental samples. During storage, the percentage retention of ascorbic acid and carotene were lower when pasteurization was not included, and in canned samples they were higher in the experimental juice than in the market samples. Pectin content showed no changes in all cases studied. The activity of pectin methylesterase slightly decreased in frozen samples, while it was a small increase in case of canned juices. During storage the microbial count of frozen and canned samples decreased when storage progressed. The addition of water and sugar during manufacturing of commercial samples did not help to obtain a product with good storage stability. There was a significant difference between the characteristics of frozen pasteurized and non pasteurized mango juice. It seems very important to pasteurize mango juice before storage in a frozen form.     

A peer-to-peer communication based content distribution protocol for incentive-aware delay tolerant networks

Wireless Networks - In the absence of Internet connectivity, a content-centric opportunistic network can be established by mobile human-held devices. However, to save battery, buffer, and bandwidth...     

A Rational Secret Sharing Scheme Against Coalition Based on Nash Equilibrium and Neighbor＇s Strategy

In order to prevent any arbitrary subsets of coalition in rational secret sharing we propose a new one- way information transmission mechanism, every player in a rational secret sharing protocol only interacts with his around two players, which means his decision is strictly based on previous neighboring player＇s strategy. Combined with the punishment strategy of Maleka＇s scheme and pay- off distribution principle in Game Theory, our scheme is capable of achieving Nash equilibrium and has the feature of anti-coalition. For the conspirators, getting the secret at the same time or in less than necessary iteration rounds is almost impossible. Without repeated involvement of the dealer, our scheme has the features of verifiability, anti- coalition, and more meaningfully, superiority of approaching reality model by taking rational behavior into consid-eration.