Cell-based Networks Research Articles

Aerodynamic Modeling of a Missile Combining Transfer Learning and Dendritic Net

During the initial stages of missile design, finding an efficient method for analyzing aerodynamic characteristics is crucial. This paper proposes a novel aerodynamic modeling method based on a limited computational fluid dynamics (CFD) dataset, combining transfer learning (TL) with Dendritic Net (DD). Initially, we employ CFD-calculated aerodynamic data to establish a pretrained model using DD. Subsequently, the model is adapted to the target domain by TL, predicting aerodynamic parameters under specific conditions. The overall aerodynamic parameters are utilized to generate a relational spectrum through DD’s white-box features, from which primary features are extracted to establish an aerodynamic polynomial model. Finally, the model’s practicality is validated by ballistic flight simulations. The innovation lies in leveraging DD to generate a relational spectrum of aerodynamic parameters, leading to a high-precision polynomial model. Research shows DD outperforms traditional cell-based networks in predicting aerodynamic parameters, and TL reduces the CFD computation workload in the target domain by 3/4 while maintaining prediction accuracy. The polynomial model exhibits superior accuracy compared to the empirical fitting formulas. The method reduces the computational workload for aerodynamic data collection, and through system identification, a high-precision polynomial model is obtained, which provides a reliable basis for missile controller design.

Neural Networks-Based Computational Modeling of Bilinear Control Systems for Conservation Laws: Application to the Control of Cogeneration

This paper considers the computational modeling of the class of bilinear control systems for hyperbolic conservation laws with nonstandard boundary conditions. These systems arise from (control) engineering applications of systems displaying propagation phenomena, i.e., integrating steam, water, and gas pipes. The aim of this paper is achieved by means of a systematic computational procedure previously introduced and adapted here for the class of systems under consideration. The procedure, based on a convergent Method of Lines ensures the convergence of the approximate numerical solution and also the preservation of the basic properties of the “true” solution as well as its Lyapunov stability. Thus, the approximate computational model allows numerical quantitative and qualitative analysis relevant to a specific problem. The computational efficiency of the procedure is ensured by its implementation based on some, possibly massively, parallel-structured devices belonging to the Artificial Intelligence field—the cell-based recurrent neural networks. As a case study, we consider a control system occurring in the cogeneration process (combined heat and electricity generation). A comparison between the results of the qualitative analysis and those of the numerical simulations demonstrates the correctness and effectiveness of the computational procedure for the dynamics and transients analysis. The paper ends with some conclusions and a list of open problems.

Offloading in HetNet: A Coordination of Interference Mitigation, User Association, and Resource Allocation

The use of heterogeneous small cell-based networks to offload the traffic of existing cellular systems has recently attracted significant attention. One main challenge is solving the joint problems of interference mitigation, user association, and resource allocation. These problems are formulated as an optimization which is then analyzed using two different approaches: Markov approximation and log-linear learning. However, finding the optimal solutions of both approaches requires complete information of the whole network which is not scalable with the network size. Thus, an approach based on a Markov approximation with a novel Markov chain design and transition probabilities is proposed. This approach enables the Markov chain to converge to the bounded near optimal distribution without complete information. In the game-theoretic approach, the payoff-based log-linear learning is used, and it converges in probability to a mixed-strategy $\epsilon$ -Nash equilibrium. Based on the principles of these two approaches, a highly randomized self-organizing algorithm is proposed to reduce the gap between optimal and converged distributions. Simulation results show that all of the proposed algorithms effectively offload more than 90 percent of the traffic from the macrocell base station to small cell base stations. Moreover, the results also show that the algorithms converge quickly irrespective of the number of possible configurations.

Comprehensive Approach Toward the Feasibility of Radio Over Fiber Technology for WiMAX Systems

To meet the explosive demands of high-capacity and broadband wireless access, modern cell-based wireless networks have trends, i.e. continuous increase in the number of cells and utilization of higher frequency bands. It leads to a large amount of Base Stations (BSs) to be deployed; therefore, cost-effective BS development is a key to success in the market. In order to reduce the system cost, Radio over Fiber (RoF) technology has been proposed since it provides functionally simple BSs that are interconnected to a central Control Station via an optical fiber. The well-known advantages of optical fiber as a transmission medium such as low loss, light weight, large bandwidth characteristics, small size, and low cable cost make it the ideal and most flexible solution for efficiently transporting radio signals to remotely located antenna sites in a wireless network. In addition to its transmission properties, the insensitivity of fiber optic cables to electromagnetic radiation is a key benefit in their implementation as the backbone of a wireless network. This paper will provide an overview of RoF technology, followed by the description of suitable architectures for the deployment of Worldwide Interoperability for Microwave Access (WiMAX) networks employing RoF systems. Main issues and challenges in the deployment of WiMAX employing RoF technology will be discussed in detail after reviewing some experimental and theoretical work. Furthermore, a simulation model for IEEE 802.16e is studied and simulation results are shown.

Hybrid BS-Cooperative Power Management Scheme with Self-Organized Sleep Mode in Virtual Cell-Based Femto Networks

A large-scale deployment of femtocell BSs (FBSs) causes substantial energy consumption. This paper proposes a hybrid BS-cooperative power management (HBCPM) scheme with self-organized sleep mode in virtual cell-based femto networks. Firstly, HBCPM builds a leader-member virtual cell framework, in which only one FBS is a FBS leader (FL) and others are FBS members (FMs). Then, the FL acts as an autonomous entity and is responsible for detecting active calls in the virtual cell coverage, while the FMs without active connections can entirely shut down pilot transmissions and the related processing all the time. So it is suited for self-organizing networks (SONs). Based on the proposed scheme, the state transition model is established by the semi-Markov stochastic process, and the analytic formulas of average cumulative delay and interference time as well as the energy consumption are derived. Meanwhile, three prominent-related schemes are also studied by the proposed model. With the practical long-term evolution (LTE) system parameters and three-dimensional femtocell network model, the numerical simulation and theoretical analysis match pretty well, and the tradeoff between the energy consumption and average cumulative delay is also manifested. Moreover, simulation results show that the proposed algorithm outperforms other three schemes in terms of average cumulative interference time and the energy consumption.

Noise-Induced Alternations in an Attractor Network Model of Perceptual Bistability

When a stimulus supports two distinct interpretations, perception alternates in an irregular manner between them. What causes the bistable perceptual switches remains an open question. Most existing models assume that switches arise from a slow fatiguing process, such as adaptation or synaptic depression. We develop a new, attractor-based framework in which alternations are induced by noise and are absent without it. Our model goes beyond previous energy-based conceptualizations of perceptual bistability by constructing a neurally plausible attractor model that is implemented in both firing rate mean-field and spiking cell-based networks. The model accounts for known properties of bistable perceptual phenomena, most notably the increase in alternation rate with stimulation strength observed in binocular rivalry. Furthermore, it makes a novel prediction about the effect of changing stimulus strength on the activity levels of the dominant and suppressed neural populations, a prediction that could be tested with functional MRI or electrophysiological recordings. The neural architecture derived from the energy-based model readily generalizes to several competing populations, providing a natural extension for multistability phenomena.

On the Issues in Implementing the Peer Model in Integrated Optical Networks

This paper contributes to a much-needed understanding of the operation, design, implementation, and evaluation of the peer model in integrated optical networks. The overlay and peer models of operation form the two fundamental architectural alternatives for interworking the control planes of optical TDM/WDM networks with those of packet or cell-based networks. Of these, the overlay model is well understood, having a precedence in IP-over-ATM networks deployed in the mid 1990s. It follows a proven approach to managing multi-area, multi-domain networks. The peer model, on the other hand, has not been implemented yet, and has also not been analyzed adequately in the literature. To enable service providers to implement either model, based on the respective merits of each, it is fundamentally important to develop a working solution for the peer model. The focus of this paper is to provide such a solution, perform a complexity analysis of the solution, and discuss its impact on the design of the protocols and the packet and transport layer devices that must interwork to realize this model.

VIRUS: a pseudo-framing method for cell-based interfaces

This paper presents the coding scheme and the timing recovery method of an interface for high-speed cell-based networks. The synchronization technique used in this interface is based on the functionality resulting from combining functions of the fiber channel with the basic features of pure asynchronous transfer mode. The main advantage of this interface is its implementability at high transmission rates, since most of its functions, like cell delineation and cell header error detection and correction, are performed at byte-level by using a pseudo-framing structure. The paper presents the basic principles of this interface, the analytic formulas for calculating its mean synchronization time under various traffic conditions and describes how the various parameters affect the method's performance.

Statistical Self-Similarity in Broadband Traffic: Results and Performance Implications

In this paper, we utilize data traffic measurements from the Ethernet LAN at IIT, Delhi to demonstrate the self-similar nature of Broadband network traffic. This ‘scale-invariant’ or self-similar behavior, detected visually as through the use of statistical techniques, is drastically different form both conventional telephone traffic and from stochastic models for packet traffic traditionally considered in the literature. We discuss the far-reaching implications of fractal nature on the design, management and performance of high-bandwidth, cell-based networks. The failure of classical traffic models to capture self-similarity necessitates the development of new mathematical approaches that are simple, accurate and realistic for aggregate data traffic. Issues such as the above, which arise in the light of this new understanding of broadband traffic, form the crux of this paper.

Error resilience in the MPEG-2 video coding standard for cell based networks – A review

The MPEG-2 video coding standard is being extensively used worldwide for the provision of digital video services. Many of these applications involve the transport of MPEG-2 video over cell-based (or packet) networks. Examples include the broadband integrated services digital network (B-ISDN) and wireless local area networks (W-LAN). All of these networks can suffer from the problem of cell loss. For example, in the B-ISDN cells are discarded at times of network congestion. In the case of the W-LAN, transmission effects can lead to high error rates within a cell which in turn can lead to cell loss. It was realised during the development of MPEG-2 that resilience to cell loss was an important issue and a number of techniques were suggested to minimise its impact. In this paper, we briefly review these techniques, demonstrate how each of the tools can be best utilised and provide results which indicate the range of cell loss rates over which each error resilience tool is useful. We also discuss briefly how the tools provided in MPEG-2 relate to other approaches suggested in the literature.

Modeling buffer utilization in cell-based networks

Variable bit rate traffic is characteristically bursty and the arrivals are highly correlated. New network technology carries such traffic in cell-based networks where the service is a discrete time, deterministic process with the service rate determined by bandwidth negotiated by the user. Managing such networks is hard, and predicting cell loss at a station with limited buffer capacity K is essential to enable the user to negotiate his quality of service requirements. We present an analysis to determine the queue length distribution and the loss probability in such circumstances. For our analysis, we use an m-phase Markov Modulated Bernoulli Process with binomial distributed batch arrivals and deterministic service and limited capacity K, i.e. a MMBP [ X] ( m) / D/1 − K queuing system. We show that the system can be analyzed using the so-called unfinished work approach. The validity of our evaluation technique is illustrated by comparing our analytical results against those obtained from an event-driven siimulation of the same system.

Simulation Modelling for Performance Comparison of Cell-Based Access Networks

A comparative study of the Distributed Queue Dual Bus (DQDB) and ATM Passive Optical Networks (APONs) is presented with emphasis on their application as access multiplexers to B-ISDN, offering traffic concentration and resource sharing. In this capacity, their performance impacts greatly on the quality of the demanding broadband services. This study is based on computer simulation using a novel modelling solution allowing the simulation to be distributed among a few workstations interconnected via a TCP/IP LAN. The performance comparison shows that DQDB offers lower Cell Delay Variation (CDV) and much lower mean delay although not equally well-bounded. This makes it a prominent candidate for the access role of customers requiring a high degree of quality. On the other hand, the APON, which was introduced with an aim to share the medium and the Optical Line Terminator (OLT) transceiver among a cluster of customers, presents a slightly worse but also acceptable performance in comparison with DQDB.

A performance comparison of cell-based local area networks

Recently, the deployment of Asynchronous Transfer Mode (ATM) technology in the Local area (ATM LANs) has received much attention. Such interest is motivated by the simplifications offered in supporting ATM in the local area, which may result in rapid deployment of ATM-based Broadband Integrated Services Digital Networks (B-ISDN). Cell-based LANs, viz. ATM LANs, provide efficient bandwidth utilization ::.md en-or recovery, as well as simplified priority implementation. We compare the performance of three cell-based LAN alternatives: the Distributed Queue Dual bus (DQDB) (1), Asynchronous Transfer Mode Ring (ATMR) (2) and switch-based ATM LANs employing ATM switches (3). We develop a versatile simulation model which is used to study the merits of each alternative.

Fuzzy control of multi-rate traffic in multimedia cell-based networks

In this paper, an intelligent scheme for controlling the QoS in multimedia, multi?rate networks is presented. The scheme implements a dynamic control mechanism, based on buffers with vaguely defined thresholds represented with fuzzy sets. This approach guarantees the QoS of real?time traffic and delivers non?realtime traffic at acceptable performance levels. The fuzzy mechanism, based on the principles of fuzzy control, dynamically responds to the alternating traffic patterns at the access node using a set of fuzzy control rules. The fuzzy control rules are carefully formulated to reduce the starvation of non?realtime traffic which is usually assigned a low priority. We also show in this paper how the proposed schemes offer an improved performance over other access control mechanisms such as moving boundaries and other static priority strategies.

The performance of DPCM operating on lossy channels with memory

We study the performance of DPCM operating over lossy channels in cell-based networks such as ATM, when statistical multiplexing is used. Since the loss of data is mainly due to traffic congestion, and the minimum unit of loss is a cell which may contain multiple DPCM codewords, the loss process can be highly correlated. The contribution of this work comes in two parts. We first give a formulation which relates the performance of DPCM, in terms of signal-to-reconstruction-noise ratio, to the channel loss conditions. In particular we take into account any correlation that exists in the loss process. We then study in detail mechanisms which give rise to such correlation. Using simple source and multiplexing models, formulae are given which characterise the loss process as a result of statistical multiplexing. As a direct result of this treatment, we know that the maximum achievable performance of DPCM with reoptimised predictors further deteriorates when the loss process is correlated. >

On the self-similar nature of Ethernet traffic

We demonstrate that Ethernet local area network (LAN) traffic is statistically self-similar , that none of the commonly used traffic models is able to capture this fractal behavior, and that such behavior has serious implications for the design, control, and analysis of high-speed, cell-based networks. Intuitively, the critical characteristic of this self-similar traffic is that there is no natural length of a "burst": at every time scale ranging from a few milliseconds to minutes and hours, similar-looking traffic bursts are evident; we find that aggregating streams of such traffic typically intensifies the self-similarity ("burstiness") instead of smoothing it.Our conclusions are supported by a rigorous statistical analysis of hundreds of millions of high quality Ethernet traffic measurements collected between 1989 and 1992, coupled with a discussion of the underlying mathematical and statistical properties of self-similarity and their relationship with actual network behavior. We also consider some implications for congestion control in high-bandwidth networks and present traffic models based on self-similar stochastic processes that are simple, accurate, and realistic for aggregate traffic.

A high performance transparent bridge

The high performance transparent bridge (HPTB) is a multiport bridge interconnecting gigabit networks. The provision of specialized hardware support coupled with proper partitioning of bridging protocol entities makes it possible to process frames at very high rates. The HPTB architecture allows concurrent bridging of asynchronous, synchronous and isochronous traffic among heterogeneous networks. It supports both traditional networks, such as variable packet size local area networks (LANs), and cell-based net works, such as distributed queue dual bus (DQDB) and metropolitan area networks (MANs). This device is capable of interconnecting any combination of high speed LANs of rates up to 800 Mbps and/or MANs of rates up to 622 Mbps.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On the self-similar nature of Ethernet traffic (extended version)

Demonstrates that Ethernet LAN traffic is statistically self-similar, that none of the commonly used traffic models is able to capture this fractal-like behavior, that such behavior has serious implications for the design, control, and analysis of high-speed, cell-based networks, and that aggregating streams of such traffic typically intensifies the self-similarity (burstiness) instead of smoothing it. These conclusions are supported by a rigorous statistical analysis of hundreds of millions of high quality Ethernet traffic measurements collected between 1989 and 1992, coupled with a discussion of the underlying mathematical and statistical properties of self-similarity and their relationship with actual network behavior. The authors also present traffic models based on self-similar stochastic processes that provide simple, accurate, and realistic descriptions of traffic scenarios expected during B-ISDN deployment. >

On the self-similar nature of Ethernet traffic

We demonstrate that Ethernet local area network (LAN) traffic is statistically self-similar, that none of the commonly used traffic models is able to capture this fractal behavior, and that such behavior has serious implications for the design, control, and analysis of high-speed, cell-based networks. Intuitively, the critical characteristic of this self-similar traffic is that there is no natural length of a "burst": at every time scale ranging from a few milliseconds to minutes and hours, similar-looking traffic bursts are evident; we find that aggregating streams of such traffic typically intensifies the self-similarity ("burstiness") instead of smoothing it.Our conclusions are supported by a rigorous statistical analysis of hundreds of millions of high quality Ethernet traffic measurements collected between 1989 and 1992, coupled with a discussion of the underlying mathematical and statistical properties of self-similarity and their relationship with actual network behavior. We also consider some implications for congestion control in high-bandwidth networks and present traffic models based on self-similar stochastic processes that are simple, accurate, and realistic for aggregate traffic.

A scheme for high-performance LAN interconnection across public MAN's

The proliferation of local area networks (LANs) and the emergence of high-bandwidth public networks will create an environment in which it will become increasingly simple and attractive to communicate among different organizations across a common public networking infrastructure. The open bridging scheme proposed, which employs inherent features of forthcoming cell-based metropolitan area networks (MANs) in order to achieve efficient interenterprise communications is introduced. It uses enhanced remote LAN bridging techniques to ensure router-level functionality with bridge-level simplicity and performance. The practicality of open bridging is shown by describing how it can be incorporated in networks using current standard protocol stacks, such as open systems interconnnection (OSI) and transmission control protocol/internet protocol (TCP/IP). >