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Wireless metropolitan area sharing networks (WMSNs) are wide-area wireless networks with nodes owned and managed by independent wireless Internet service providers (WISPs). To support seamless roaming in emerging WMSNs, in this paper, we propose a localized and distributed authentication and billing architecture that aims at enabling efficient and privacy-preserving mutual authentication between mobile users (MUs) and WISPs. User anonymity and identity privacy can be protected, even in the presence of collusion between WISPs and a roaming broker (RB), which is considered to be the strongest user privacy protection. An efficient billing architecture is introduced and performed in the same stage of roaming, where U-tokens are defined and can be purchased by MUs from an RB as authentication credentials for the MUs to access the wireless network. The WISPs, thus, can cash the collected U-tokens in the RB for payment. We show that the proposed authentication and billing architecture can support localized inter-WISP authentication through the divisible blind signature scheme and a local witness strategy. A detailed analysis on a number of performance metrics, such as computation time and power consumption, is given to validate the performance of the proposed architectures. Index Terms--Billing, partially blind signature, privacy protection, roaming, wireless metropolitan area sharing networks (WMSNs).

The mobility pattern of users is one of the distinct features of vehicular ad hoc networks (VANETs) compared with other types of mobile ad hoc networks (MANETs). This is due to the higher speed and the roadmap-restricted movement of vehicles. In this paper, we propose a new analytical mobility model for VANETs based on product-form queueing networks. In this model, we map the topology of the streets and the behavior of vehicles at both intersections and different parts of the streets onto different parameters of a BCMP open queueing network comprising M/G/[infinity] nodes. This model represents a sparse situation for VANETs. To include the effect of dense situation on the mobility model, we modify the proposed queueing network as a new one comprising nodes with state-dependent service rates, i.e., M/G(n)/[infinity] nodes. With respect to the product-form solution property of the proposed queueing networks, we are able to find the spatial traffic distribution for vehicles at both sparse and dense situations. Furthermore, we are able to modify the proposed queueing network to find the lower and upper bounds for the probability of connectivity. In the last part of this paper, we show the flexibility of the proposed model by several numerical examples and confirm our modeling approach by simulation. Index Terms--Connectivity, mobility model, queueing network, spatial traffic distribution, vehicular ad hoc network (VANET).

Network feedback in a congestion-control system is subject to delay, which can significantly affect stability and performance of the entire system. While most existing stability conditions explicitly depend on delay [D.sub.i] of individual flow i, a recent study [1] shows that the combination of a symmetric Jacobian A and condition p(A) < 1 guarantees local stability of the system regardless of [D.sub.i]. However, the requirement of symmetry is very conservative and no further results have been obtained beyond this point. In this technical note, we proceed in this direction and gain a better understanding of conditions under which congestion-control systems can achieve delay-independent stability. Towards this end, we first prove that if Jacobian matrix A satisfies [parallel] A [parallel] < 1 for any monotonic induced matrix norm [parallel] x [parallel], the system is locally stable under arbitrary diagonal delay [D.sub.i]. We then derive a more generic result and prove that delay-independent stability is guaranteed as long as A is Schur diagonally stable [2], which is also observed to be a necessary condition in simulations. Utilizing these results, we identify several classes of well-known matrices that are stable under diagonal delays if [rho](A) < 1 and prove stability of MKC [1] with arbitrary parameters [[alpha].sub.i] and [[beta].sub.i]. Index Terms--Delay-independent stability, diagonal delay, max-min congestion control.

We generalize and unify a range of recent results in quantized control systems (QCS) and networked control systems (NCS) literature and provide a unified framework for controller design for control systems with quantization and time scheduling via an emulation-like approach. A crucial step in our proofs is finding an appropriate Lyapunov function for the quantization/ time-schednling protocol which verifies its uniform global exponential stability (UGES). We construct Lyapunov functions for several representative protocols that are commonly found in the literature, as well as some new protocols not considered previously. Our approach is flexible and amenable to further extensions which are briefly discussed. Index Terms--Networked control systems (NCS), quantized control systems (QCS).

An open standard protocol for networking of energy meters under the simple network-management protocol (SNMP) environment is proposed. Since the SNMP is quite popular for network enabling of uninterruptible power supplies, the necessary support hardware and software already exist. Hence, migrating energy meter connectivity to the transfer control protocol/Internet protocol-based SNMP would be an easy task. A sample network is created under the LabVIEW virtual instrumentation environment and studied to validate the proposed open standard protocol for networking of energy meters. Index Terms--Automatic meter reading, management information base (MIB), network-management system (NMS), networking of energy meters, simple network-management protocol (SNMP).

This paper presents a new approach to solving the problem of stabilization for networked control systems. Mean-square asymptotic stability is derived for the closed-loop networked control systems, and based on this, a controller design procedure is proposed for stabilization purpose. An inverted pendulum system is utilized to show the effectiveness and applicability of the proposed results. Index Terms--Delay, mean-square stability, networked control systems, stabilization.

The deployment of small ( Index Terms--Buildings, building management systems, cogeneration, cooling, cost optimal control, dispersed storage and generation, distributed control, optimization methods, power system economics, power system planning.

There is significant interest in the data mining and network management communities about the need to improve existing techniques for clustering multivariate network traffic flow records so that we can quickly infer underlying traffic patterns. In this paper, we investigate the use of clustering techniques to identify interesting traffic patterns from network traffic data in an efficient manner. We develop a framework to deal with mixed type attributes including numerical, categorical, and hierarchical attributes for a one-pass hierarchical clustering algorithm. We demonstrate the improved accuracy and efficiency of our approach in comparison to previous work on clustering network traffic. Index Terms--Traffic analysis, network management, network monitoring, clustering, classification and association rules, hierarchical clustering.

This article deals with the analysis, diagnosis and management techniques that make use of information on access network topology and crosstalk to give maximum digital subscriber line performance. Maintenance tools with digital subscriber line capability maximize loop performance automatically to reconfigure faulty lines to profiles, which stabilize them.

Network utility maximization (NUM) problem formulations provide an important approach to conduct network resource allocation and to view layering as optimization decomposition. In the existing literature, distributed implementations are typically achieved by means of the so-called dual decomposition technique. However, the span of decomposition possibilities includes many other elements that, thus far, have not been fully exploited, such as the use of the primal decomposition technique, the versatile introduction of auxiliary variables, and the potential of multilevel decompositions. This paper presents a systematic framework to exploit alternative decomposition structures as a way to obtain different distributed algorithms, each with a different tradeoff among convergence speed, message passing amount and asymmetry, and distributed computation architecture. Several specific applications are considered to illustrate the proposed framework, including resource-constrained and direct-control rate allocation, and rate allocation among QoS classes with multipath routing. For each of these applications, the associated generalized NUM formulation is first presented, followed by the development of novel alternative decompositions and numerical experiments on the resulting new distributed algorithms. A systematic enumeration and comparison of alternative vertical decompositions in the future will help complete a mathematical theory of network architectures. Index Terms--Congestion control, distributed algorithm, mathematical programming/optimization, network control by pricing, network utility maximization (NUM), rate control, resource allocation.

A novel model-predictive-control strategy with a timeout scheme and p-step-ahead state estimation is presented in this paper to overcome the adverse influences of stochastic time delays and packet losses encountered in network-based distributed real-time control. An open-loop unstable magnetic-levitation (maglev) test bed was constructed and employed for its experimental verification. The compensation algorithms developed in this paper deal with the network-induced stochastic time delays and packet losses in both the forward path and the feedback path simultaneously. With the p-sampling-period delay upper bound, the networked control system (NCS) can also accommodate up to p-1 successive packet losses. Experimental results demonstrate the feasibility and effectiveness of this networked real-time control strategy. [DOI: 10.1115/1.2232692] Keywords: networked control system, time delays, packet losses, model prediction

Byline: Lawrence Cheng, Alex Galis, Antonis J. Lazanakis, George Karetsos, Spyros Denazis Self-adaptation to changes in network context or self-contextual functionality refers to the capability of network nodes to dynamically reconfigure themselves in changing heterogeneous networking environments, in which new services and protocols will be rapidly created and deployed on demand. A novel programmable architecture, called the Future Active IP Networks (FAIN) node, is presented to address the described issues.