56 research outputs found

    Evaluation Study for Delay and Link Utilization with the New-Additive Increase Multiplicative Decrease Congestion Avoidance and Control Algorithm

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    As the Internet becomes increasingly heterogeneous, the issue of congestion avoidance and control becomes ever more important. And the queue length, end-to-end delays and link utilization is some of the important things in term of congestion avoidance and control mechanisms. In this work we continue to study the performances of the New-AIMD (Additive Increase Multiplicative Decrease) mechanism as one of the core protocols for TCP congestion avoidance and control algorithm, we want to evaluate the effect of using the AIMD algorithm after developing it to find a new approach, as we called it the New-AIMD algorithm to measure the Queue length, delay and bottleneck link utilization, and use the NCTUns simulator to get the results after make the modification for the mechanism. And we will use the Droptail mechanism as the active queue management mechanism (AQM) in the bottleneck router. After implementation of our new approach with different number of flows, we expect the delay will less when we measure the delay dependent on the throughput for all the system, and also we expect to get end-to-end delay less. And we will measure the second type of delay a (queuing delay), as we shown in the figure 1 bellow. Also we will measure the bottleneck link utilization, and we expect to get high utilization for bottleneck link with using this mechanism, and avoid the collisions in the link

    On the delay and link utilization with the new-additive increase multiplicative decrease congestion avoidance and control algorithm

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    Additive increase multiplicative decrease (AIMD) algorithm is the prevailing algorithm for congestion avoidance and control in the Internet. Reducing the end-to-end delays and enhancement of the link utilization are the important goals of this algorithm. In this work, we continue to study the performance of the New-AIMD (additive increase multiplicative decrease) mechanism as one of the core protocols for TCP, to avoid and control the congestion. We want to evaluate the effect of using the AIMD algorithm after developing it, which we called the New-AIMD algorithm, to find a new approach to measure the end-to-end delay and bottleneck link utilization and use the NCTUns simulator to obtain the results after making the modification for the mechanism. We will use the DropTail mechanism as the active queue management mechanism (AQM) in the bottleneck router. After the implementation of our new approach with a different number of flows, we expect the end-to-end delay to be less when we measure the delay dependent on the throughput for the entire system. In addition, we will measure the bottleneck link utilization using this mechanism and expect to get high utilization for bottleneck link and avoid the collisions in the link

    Efficiency and fairness of new-additive increase multiplicative decrease congestion avoidance and control algorithm

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    When using of the Internet increased dramatically; the congestion avoidance problem became even more important. The congestion is usually caused by the multiplexing for packets when the packets are at the bottleneck links. Efficiency and fairness are the important metrics in the performance of congestion avoidance mechanisms. And also all of the researches for the congestion avoidance algorithms, interest about this parameters metrics to evaluate the performance of the algorithms. This research studied the performance of the New-Additive Increase Multiplicative Decrease (AIMD) algorithm as one of the core protocols for the TCP congestion avoidance and control mechanism. In addition, to evaluate the effect of using the AIMD algorithm after its development to measure the efficiency and fairness and find new enhancement results for our approach, which named as the New-AIMD algorithm. The NCTUns simulator is used to obtain the results after implementing the modifications to the mechanism

    The delay with new-additive increase multiplicative decrease congestion avoidance and control algorithm.

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    As the Internet becomes increasingly heterogeneous, the issue of congestion control becomes ever more important. And the queue length and end-to-end (congestion) delays are some of the important things in term of congestion avoidance and control mechanisms. In this research we continued to study the performances of the New-Additive Increase Multiplicative Decrease (AIMD) algorithm as one of the core protocols for TCP congestion avoidance and control mechanism, we want now to evaluate the effect of using the New-AIMD algorithm to measure the queue length and end-to-end delays and we will use the NCTUns simulator to get the results after make the modification of the mechanism. And we will use the Drop tail mechanism as Active Queue Management (AQM) in the bottleneck router. After implementation of our new approach with different number of flows, we will measure the delay for two types of delays (queuing delay and end-to-end delay), we expect the delay will be less with using our mechanism comparing with the mechanism in the previous study. Now and after got this results as low delay for bottleneck link case, we know the New-AIMD mechanism work as well under the network condition in the experiments

    Complexity and dynamic characteristics of a new discrete-time hyperchaotic model

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    Based on two of the existing one-dimensional chaotic maps and the two-dimensional Hénon map, a new two-dimensional Hénon-Gaussian-Sine model (2D-HGSM) is proposed. Basic dynamic characteristics of the 2D-HGSM are studied from the following three aspects: trajectory, bifurcation diagram and Lyapunov exponents. The complexity of 2D-HGSM is investigated by means of Approximate entropy. Performance evaluations show that the 2D-HGSM has higher complexity level, better ergodicity, wider chaotic and hyperchaotic region than different chaotic maps. Furthermore, the 2D-HGSM exhibits a qualitatively different chaotic behavior with respect to the variation of its corresponding parameters. Therefore, the 2D-HGSM has good application prospects in secure communication

    A new 2D Hénon-logistic map for producing hyperchaotic behavior

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    Derived from the two-dimensional (2D) Hénon map and the one-dimensional (1D) Logistic map, this paper proposes a new 2D hyperchaotic map, called the 2D Hénon-Logistic map (2D-HLM). The dynamics of the 2D-HLM are investigated by means of equilibria, stability analysis, trajectory, Lyapunov exponent, and bifurcation diagram. Mathematical analysis reveals that the 2D-HLM has four unstable equilibria. Besides that, it has wide chaotic and hyperchaotic behaviors with very limited periodic windows. To evaluate the complexity performance of the 2D-HLM, Approximate entropy is used to analyze its time series. Consequently, the 2D-HLM exhibits extremely complex nonlinear behavior. With all of these attributes, the 2D-HLM would be very appropriate to produce a pseudo-random number generator that can be used in chaos-based cryptographic applications

    Enhancing chaos in multistability regions of Duffing map for an asymmetric image encryption algorithm

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    We investigate the dynamics of a two-dimensional chaotic Duffing map which exhibits the occurrence of coexisting chaotic attractors as well as periodic orbits with a typical set of system parameters. Such unusual behaviors in low-dimensional maps is inadmissible especially in the applications of chaos based cryptography. To this end, the Sine-Cosine chaotification technique is used to propose a modified Duffing map in enhancing its chaos complexity in the multistable regions. Based on the enhanced Duffing map, a new asymmetric image encryption algorithm is developed with the principles of confusion and diffusion. While in the former, hyperchaotic sequences are generated for scrambling of plain-image pixels, the latter is accomplished by the elliptic curves, S-box and hyperchaotic sequences. Simulation results and security analysis reveal that the proposed encryption algorithm can effectively encrypt and decrypt various kinds of digital images with a high-level security.Comment: 15 pages, 15 figure

    The TCP-based new AIMD congestion control algorithm

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    Congestion control is one of the fundamental issues in computer networks. Without proper congestion control mechanisms there is the possibility of inefficient utilization of resources, ultimately leading to network collapse. Hence congestion control is an effort to adapt the performance of a network to changes in the traffic load without adversely affecting users perceived utilities. AIMD (Additive Increase Multiplicative Decrease) is the best algorithm among the set of liner algorithms because it reflects good efficiency as well as good fairness. Our control model is based on the assumption of the original AIMD algorithm; we show that both efficiency and fairness of AIMD can be improved. We call our approach is New AIMD. We present experimental results with TCP that match the expectation of our theoretical analysis

    A Simple Conservative Chaotic Oscillator with Line of Equilibria: Bifurcation Plot, Basin Analysis, and Multistability

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    Here, a novel conservative chaotic oscillator is presented. Various dynamics of the oscillator are examined. Studying the dynamical properties of the oscillator reveals its unique behaviors. The oscillator is multistable with symmetric dynamics. Equilibrium points of the oscillator are investigated. Bifurcations, Lyapunov exponents (LEs), and the Poincare section of the oscillator's dynamics are analyzed. Also, the oscillator is investigated from the viewpoint of initial conditions. The study results show that the oscillator is conservative and has no dissipation. It also has various dynamics, such as equilibrium point and chaos. The stability analysis of equilibrium points shows there are both stable and unstable fixed points

    Degenerating the butterfly attractor in a plasma perturbation model using nonlinear controllers

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    In this work, the dynamical behaviors of a low-dimensional model, which governs the interplay between a driver associated with pressure gradient and relaxation of instability due to magnetic field perturba- tions, are investigated. Besides that, two nonlinear controllers are constructed precisely to shift the equi- libria of the plasma model apart from each other. Simulation results show that shifting the equilibria can change the spacing of chaotic attractors, and subsequently break the butterfly wings into one or two symmetric pair of coexisting chaotic attractors. Furthermore, stretching the equilibria of the system apart enough from each other gives rise to degenerate the butterfly wings into several periodic orbits. In ad- dition, with appropriate initial conditions, the complex multistability behaviors including the coexistence of butterfly chaotic attractor with two point attractors, the coexistence of transient transition chaos with completely quasi-periodic behavior, and the coexistence of symmetric Hopf bifurcations are also observed
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