International Journal of Mathematical Models and Methods in Applied Sciences

ISSN: 1998-0140
Volume 12, 2018

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 12, 2018

Title of the Paper: Analysis on Influence of Bottom Sediment Types on Side-Scan Sonar Imaging Properties


Authors: Zhang Kaihan, Yuan Fei, Cheng En

Pages: 60-66

Abstract: Side-scan sonar is widely used in the field of most kinds of detection, due to the imaging prooerties side-scan sonar generates corresponding noise. The different bottom sediment types causing different effects on seabed reverberation effects. After considering the seabed reverberation statistical model, four typical probability distribution models are compared by experiments to get the conclusion that Gamma distribution model is superior from the fitting effect and fastest calculation speed. On the basis of this, model can adjusts parameters of Gamma distribution with different types of bottom sediment to simulate the noise. Using the image gray scale mean and the gray level entropy, the image distribution parameters of the image are analyzed by multiple regression analysis, and the corresponding model is obtained. According to the model, it is possible to simulate noise caused by the reverberation of different bottom sediment types. This result provides an important basis for the separation of the subsurface image and the subsequent de-noising.

Title of the Paper: Dual Solutions in the Stagnation-Point Flow Over a Shrinking Sheet


Authors: A. Ishak

Pages: 56-59

Abstract: In the present study, we consider a stagnation point flow over a stretching or shrinking sheet with slip effect at the boundary. The external flow and the stretching/shrinking velocities are assumed to vary linearly from the stagnation point. Different from the previous studies, we consider both stretching and shrinking cases, as well as the slip effect at the boundary. The numerical results show that the solution is unique for the stretching case, while dual solutions are possible for the shrinking case. A stability analysis is performed for the case where dual solutions exist to determine the stability of the solutions. Applying the slip condition increases the range of solutions for the shrinking case.

Title of the Paper: Adaptive Compression Method of Underwater Image Based on Perceived Quality Estimation


Authors: Cai Yaqiong, Zou Haixia, Yuan Fei

Pages: 43-55

Abstract: Underwater image compression is one of the most important and essential part in underwater image transmission system, the effective image quality assessment and estimation of the compressed image can make the system adjust the compression ratio better in the compression process, improve the efficiency of image transmission system. This paper respectively estimate the underwater image compression perceived quality based on the strategy of coding compression and the compression strategy of compressive sensing, built model base on the mapping between image activity measurement(IAM) and BPP-SSIM curve, and obtain model parameters, then predict the perceived quality of image compression based on image activity measurement, compression ratio and compression strategy. The experimental results show that the model can effectively fit the quality curve of underwater image compression, according to the rules of the parameters in this model, the perceived quality of underwater compressed image can be estimated in the small error range. The presented method can effectively estimate the perceived quality of underwater compressed image , and effectively balance the relationship between the compression ratio and compression quality, reduce the pressure of the data cache, and improve the efficiency of underwater image communication system.

Title of the Paper: Enhanced Fault Tolerant Execution Unit in Out of Order Processor Core


Authors: Harini Sriraman, Pattabiraman Venkatasubbu

Pages: 37-42

Abstract: With increasing complexity of processor architectures and their vulnerability to hard faults, it is vital to have self-repairing processor architectures. This paper proposes the idea of autonomic repairing of permanent hard faults in the functional units of an out-of order processor core using reconfigurable FPGA. The technique proposed utilizes the existing reconfigurable hardware in the new range of embedded systems like Intel Atom E6X5C series. The proposed technique includes an on-chip buffer, a fault status table (fully associative) and few control signals to the existing core. To perform self-repairing, decoder will identify reference to the faulty unit and initiate the reconfigurable hardware to be configured as the faulty unit referenced. Dispatch unit will help resolve the reservation station conflicts for the reconfigurable hardware. Execution of instruction that referenced the faulty unit gets executed in the reconfigurable unit. Dispatch unit and the buffers helps complete the out-of order execution and in-order commit of the instructions that referenced a faulty unit. A hypothetical architecture that loosely resembles ALPHA 21264 is designed as a test bed for analyzing the proposed self-repairing mechanism. Area and time overhead analysis are done using Cadence NCVerilog simulator, Xilinx-Vivaldo ISE and FPGA Prototype board. Spatial and temporal costs of the proposed design are around 2% and 2.64% respectively. With recent increase in hybrid architectures that has FPGA tightly coupled with ASIC processor core, the proposed solution maximizes the reliability of the processor core without much area and time overhead.

Title of the Paper: Markov Chain Modeling for Reliability Estimation of the Self-Excited Induction Generator


Authors: Y. Naoui, H. Meglouli, S. Abudura

Pages: 26-36

Abstract: A new approach to the prediction of the reliability of Self-excited induction generator is presented in this paper. In this approach, a reliability analysis based on the Markov chain is used to diagnose the parameters that influence on the quality of the produced electrical energy. For this, we have designed mathematical models to the vacuum self-excited induction generator and load. These models are simulated by the MATLAB software to determine the parameters that affect the voltage supplied by the generator .After allowing us to study the influence of failures of devices on the system operation, we perform an analysis of the Failure Modes and their Effects which is a method commonly used in the first step of a reliability study. Then a model of Markov chain of the installation is applied to the system for studying the reliability and determines the failure probability of the installation components.

Title of the Paper: Unsteady Flow of a Newtonian Fluid in a Contracting and Expanding Pipe


Authors: T. S. L. Radhika, M. B. Srinivas, T. Raja Rani, A. Karthik

Pages: 21-25

Abstract: In this paper, we considered the unsteady flow of Newtonian fluid in a contracting and expanding pipe. Flow is considered to be in a circular pipe whose radius is a function of time. Further, the flow is taken to be under the influence of a negative pressure gradient that is expressed as a separable function of spatial variable and time. The function in the spatial variable is taken in two forms: linear and exponential (both decreasing) and a sinusoidal function has been assumed in terms of the time variable. Fluid flow equations have been derived under the assumptions that the fluid is incompressible and the flow is axi-symmetric. The resulting coupled system of partial differential equation in terms of the radial and axial velocity components have been solved using Homotopy perturbation method. The effect of the parameters related to the contraction and expansion of the pipe and the frequency of oscillations, on the wall shear stress and volumetric flux has been studied for the two models developed in this work and the results are presented and discussed.

Title of the Paper: Influence of Flooding Compartment on the Ship’s Safety Mironiuk Waldemar


Authors: Mironiuk Waldemar

Pages: 16-20

Abstract: Every damage to a ship results in certain effects, ie flooding water over one or more watertight compartments, which affects changes in stability and position of the ship. Determination of these changes is the basis for the sub-capacity calculations related to the operation of a damaged ship. During the ship's operation, unusual damage not anticipated in the stability documentation may occur, so it is necessary to know the methods of calculating the subdivision. During the ship's operation at sea a significant threat to his safety is a fire. Rarely causes sinking of the ship, however, the damage that it leaves is usually very serious and as always, depending on the level of crew training in the area of emergency response. The main extinguishing agent used on ships is usually sea water, which in large quantities poses a threat to the stability and submarine of the ship. Therefore, the main focus of the work was to determine the impact of flooding of high-stability compartments of the ship. The results of the calculations presented in the work include information on the amount of water in the range causing deterioration of the stability of the ship.

Title of the Paper: Iterative Solution in Adaptive Model Predictive Control by Using Fixed-Point Transformation Method


Authors: Hamza Khan, Jozsef K. Tar, Imre J. Rudas, Gyorgy Eigner

Pages: 7-15

Abstract: In this paper the application of a recently introduced simple iterative solution of the Nonlinear Programming approach is investigated for the Adaptive Model Predictive Control of a strongly nonlinear dynamic paradigm, the Duffing oscillator. The main idea is to replace the numerically much more complex Reduced Gradient method in the optimization task under constraints when the cost function has relatively simple structure, but it does not allow the use of the traditional LQR controller. The suggested iterative solution is based on Banach’s Fixed Point Theorem that has twofold utilization: in approaching the solution of the optimization task, and in the realization of the adaptive behavior of the controller. In the presented, Julia language-based numerical simulations certain numerical tricks are also applied that were used to stabilize the run of the numerical simulations. The numerical examples illustrate the applicability of the suggested method for a wide class of cost function structures.

Title of the Paper: Event-Triggered Global Robust Adaptive Stabilization for a Class of Nonlinear Systems


Authors: Wei Liu, Jie Huang

Pages: 1-6

Abstract: In this paper, we study the event-triggered global robust adaptive stabilization problem for a class of nonlinear systems with unity relative degree, which contain not only disturbances, but also static parameter uncertainties and dynamic uncertainties. By combining the robust control technique and the adaptive control technique, we design a digital control law, a digital adaptive law, and an event-triggered mechanism to stabilize the system in the sense that the state of the closed-loop system is globally ultimately bounded. What’s more, we show that the Zeno behavior does not happen. Finally, we illustrate our approach by applying it to the controlled Lorenz system.