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Networks in which the processing of jobs occurs both sequentially and in parallel are prevalent in many application domains, such as computer systems, healthcare, manufacturing, and project management. The parallel processing of jobs gives rise to synchronization constraints that can be a main reason for job delay. In comparison with feed-forward queueing networks that have only sequential processing of jobs, the approximation and control of networks that have synchronization constraints is less understood. One well-known modeling framework in which synchronization constraints are prominent is the fork-join processing network. Our objective is to find scheduling rules for fork-join processing networks with multiple job types in which there is first a fork operation, then activities that can be performed in parallel, and then a join operation. The difficulty is that some of the activities that can be performed in parallel require a shared resource. We solve the scheduling problem for that shared server (that is, which type of job to prioritize at any given time) when that server is in heavy traffic and prove an asymptotic optimality result. Supplemental Material: The e-companion is available at https://doi.org/10.1287/moor.2018.0935. Keywords: fork-join processing network * scheduling control * asymptotic optimality, 1. Introduction Networks in which processing of jobs occurs both sequentially and in parallel are prevalent in many application domains, such as computer systems (Xia et al. [35]), healthcare (Armony [...]

One staple of living in our information society is having access to the web. Web-connected devices interpret our queries and retrieve information from the web in response. Today's web devices even purport to answer our queries directly without requiring us to comb through search results in order to find the information we want. How do we know whether a web device is trustworthy? One way to know is to learn why the device is trustworthy by inspecting its inner workings (Lehrer The Monist, 78(2), 156-170 1995 (See CR4); Humphreys 2004 (See CR2), Episteme, 6(2), 221-229 2009 (See CR3)). But ordinary users of web devices cannot inspect their inner workings because of their scale, complexity, and the corporate secrecy which enshrouds both the procedures by which the devices operate and the companies that make them (Pasquale 2015 (See CR6)). Further piling on this predicament, authors have criticized web technology on the grounds that the invisibility of the web devices' inner workings prevents users from critically assessing the procedures that produce a given output, in some cases, barring users from fulfilling their epistemic responsibilities (Simon Ethics and Information Technology, 12(4), 343-355 2010 (See CR7); Miller and Record Episteme, 10(2), 117-134 2013 (See CR5)). I consider four broad kinds of reasons which we can acquire without inspecting the inner workings of black-boxed technology: individual understanding, expert testimony, testing through experience, and social vetting; and show how each is a viable method of appraising black-boxed technology. By deploying these methods, we can remain responsible inquirers while nonetheless benefitting from today's epistemic resources on the web., Author(s): E. S. Dahl [sup.1] Author Affiliations: (Aff1) 0000 0004 0456 0419, grid.182981.b, Reed College, , Box 220, 3203 SE Woodstock Blvd, 97202, Portland, OR, USA One staple of living [...]

Abstract. The Internet has assumed a central role in the global economy facilitating commerce and communication and is thus central to many areas of information systems (IS) research. In particular, [...]

Abstract. Shareholder activism through corporate governance proposals is a prominent avenue for investors to voice their concerns in corporate governance matters. However, shareholder proposals have an uneven effect on corporate [...]

We study a resource-sharing network where each job requires the concurrent occupancy of a subset of links (servers/resources), and each link's capacity is shared among job classes that require its [...]

Driving speed is one of the most critical indicators in safety evaluation and network monitoring in freight transportation. Speed prediction model serves as the most efficient method to obtain the data of driving speed. Current speed prediction models mostly focus on operating speed, which is hard to reveal the overall condition of driving speed on the road section. Meanwhile, the models were mostly developed based on the regression method, which is inconsistent with natural driving process. Recurrent neural network (RNN) is a distinctive type of deep learning method to capture the temporary dependency in behavioral research. The aim of this paper is to apply the deep learning method to predict the general condition of driving speed in consideration of the road geometry and the temporal evolutions. 3D mobile mapping was applied to obtain road geometry information with high precision, and driving simulation experiment was then conducted with the help of the road geometry data. Driving speed was characterized by the bimodal Gauss mixture model. RNN and its variants including long short-term memory (LSTM) and RNN and gated recurrent units (GRUs) were utilized to predict speed distribution in a spatial-temporal dimension with KL divergence being the loss function. The result proved the applicability of the model in speed distribution prediction of freight vehicles, while LSTM holds the best performance with the length of input sequence being 400 m. The result can be related to the threshold of drivers' information processing on mountainous freeway. Multiple linear regression models were constructed to be a contrast with the LSTM model, and the results showed that LSTM was superior to regression models in terms of the model accuracy and interpretability of the driving process and the formation of vehicle speed. This study may help to understand speed change behavior of freight vehicles on mountainous freeways, while providing the feasible method for safety evaluation or network efficiency analysis., 1. Introduction In the driving process of freight vehicles, driving speed is one of the most important indicators in safety evaluation and efficiency analysis. Currently, the speed prediction model plays [...]

INTRODUCTION There is no single criminal justice 'system' in California--just hundreds of separate agencies, each with its own culture, organization, and data. Offenders who are brought into 'the system' are [...]

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).

Wireless local area networks (WLANs) have become a ubiquitous high-speed data-access technology. The recent IEEE 802.11e standard provides quality-of-service (QoS) support, and the pending 802.11n standard further increases the transmission rate by using the multiple-input-multiple-output (MIMO) technique. Multiple antennas can be used to improve the performance gain by either increasing the transmission reliability through spatial diversity or increasing the transmission rate through spatial multiplexing. This new characteristic at the wireless physical (PHY) layer requires the corresponding adaptation at the medium access control (MAC) layer to reach the best performance gain. In this paper, we propose cross-layer design schemes for WLANs under two different MAC protocols: the carrier sense multiple access with collision avoidance (CSMA/CA)-based 802.11e MAC and the slotted Aloha MAC. For the 802.11e MAC, two different contention window (CW) size adaptation schemes, namely, U-MAC and D-MAC, are proposed, which facilitate the MAC protocol to jointly adapt its CW size with the PHY layer's MIMO operating parameters. For the slotted Aloha MAC, a cross-layer optimization framework NUM-O is proposed to jointly optimize the MIMO configuration at the PHY layer and the persistent probabilities for different classes of multimedia traffic at the MAC layer. A distributed algorithm NUM-D based on dual decomposition and a simplified version NUM-S are also proposed. Simulation results are presented to show the effectiveness of the proposed methods. Index Terms--Multiple-input-multiple-output (MIMO), network utility maximization (NUM), optimization, slotted Aloha, wireless local area networks (WLANs), 802.11e.

In this paper, we study the impact of node mobility on link duration in multihop mobile networks. In multihop mobile networks, each node is free to move, and each link is established between two nodes. A link between two nodes is established when one node enters the transmission range of the other node, and the link is broken when either node leaves the transmission range of the other. The time interval during which the link remains active is referred to as the link duration. We develop an analytical model for link duration in multihop mobile networks. We find that the link duration for two nodes is determined by the relative speed between the two nodes and the distance during which the link is connected, which are, in turn, determined by the angles between the two nodes' velocities and the angle of one node incident to the other node's transmission range, respectively. The analytical result is then extended to model multipoint links, which appear in existing group mobility models. The accuracy of our framework is validated by simulations based on existing mobility models. The results show that our model can accurately describe the link-duration distribution for point-to-point and multi-point links in multihop mobile networks, particularly when the transmission range of each node is relatively smaller than the entire network coverage. Index Terms--Link duration, multihop mobile networks.

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).

Earliest arrival flows capture the essence of evacuation planning. Given a network with capacities and transit times on the arcs, a subset of source nodes with supplies and a sink [...]

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).

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2008.10.007 Byline: Pere Barlet-Ros (a), Gianluca Iannaccone (b), Josep Sanjuas-Cuxart (a), Josep Sole-Pareta (a) Keywords: Network monitoring; Load shedding; Traffic sampling Abstract: We present the design of a predictive load shedding scheme for a network monitoring platform that supports multiple and competing traffic queries. The proposed scheme can anticipate overload situations and minimize their impact on the accuracy of the traffic queries. The main novelty of our approach is that it considers queries as black boxes, with arbitrary (and highly variable) input traffic and processing cost. Our system only requires a high-level specification of the accuracy requirements of each query to guide the load shedding procedure and assures a fair allocation of computing resources to queries in a non-cooperative environment. We present an implementation of our load shedding scheme in an existing network monitoring system and evaluate it with a diverse set of traffic queries. Our results show that, with the load shedding mechanism in place, the monitoring system can preserve the accuracy of the queries within predefined error bounds even during extreme overload conditions. Author Affiliation: (a) Dept. Arquitectura de Computadors, Universitat Politecnica de Catalunya (UPC), Campus Nord, Edif. D6, C. Jordi Girona, 1-3, 08034 Barcelona, Spain (b) Intel Research, 2150 Shattuck Avenue, Berkeley, CA 94704, United States Article History: Received 22 January 2008; Revised 6 October 2008; Accepted 8 October 2008 Article Note: (miscellaneous) Responsible Editor: M. Smirnov

Many distributed collective decision-making processes must balance diverse individual preferences with a desire for collective unity. We report here on an extensive session of behavioral experiments on biased voting in networks of individuals. In each of 81 experiments, 36 human subjects arranged in a virtual network were financially motivated to reach global consensus to one of two opposing choices. No payments were made unless the entire population reached a unanimous decision within 1 min, but different subjects were paid more for consensus to one choice or the other, and subjects could view only the current choices of their network neighbors, thus creating tensions between private incentives and preferences, global unity, and network structure. Along with analyses of how collective and individual performance vary with network structure and incentives generally, we find that there are well-studied network topologies in which the minority preference consistently wins globally; that the presence of 'extremist' individuals, or the awareness of opposing incentives, reliably improve collective performance; and that certain behavioral characteristics of individual subjects, such as 'stubbornness,' are strongly correlated with earnings. behavioral game theory | collective decision making | network science

A distributed algorithm, where only one user for each cell is involved in the adjustment of weight and power, is proposed for joint diversity and power control in wireless networks. We prove that the power and weight of this algorithm converge to the optimal power and weight that minimize the total power consumption. In addition, we also prove some properties that facilitate the operation of the admission control in which the distributed algorithm is incorporated. Two approaches are proposed for the admission control: 1) the admission criterion and 2) the admission control algorithm. The proposed admission criteria are realized by considering a set of inequalities, whereas the proposed admission control algorithm is based on the connection removal. It is shown that the number of inequalities for the proposed admission criteria can be reduced from the number of users to the number of base stations so that the computational complexity of the proposed admission criteria can largely be reduced. In addition, we have found in the simulation results that the proposed admission control algorithm outperforms other admission control algorithms in terms of the average execution time and computational complexity. Index Terms--Admission control, connection removal, diversity, minimum variance distortionless response (MVDR), power control.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2008.08.017 Byline: Vijay K. Verma (a), Ramesh C. Joshi (a), Bin Xie (b), Dharma P. Agrawal (b) Keywords: Bloated state; Cloning; Itinerary partitioning; Mobile agent; Network management; Simple network management protocol (SNMP) Abstract: As computer networks increase in size, it is critical to provide efficient and scalable network management. Integration of mobile agents (MAs) with simple network management protocol (SNMP) provides a decentralized network management architecture that overcomes the limitations of the legacy SNMP client/server structure. However, as an MA travels through its itinerary, acquiring the network state at each managed node, its size linearly increases node-by-node and it may be unexpectedly bloated. As a result, a bloated MA will have difficulty in migrating from one node to another. We show that the network response time grows exponentially as the MA size increases linearly. In this paper, we propose a new strategy called itinerary partitioning approach (IPA) that exploits cloning capability of MAs to effectively address this bloated state phenomenon. The analytical model shows the effectiveness of our proposed IPA in terms of network response time. We have implemented the IPA in a practical test-bed network and the results seem to be very encouraging. Author Affiliation: (a) Department of Electronics and Computer Science, Indian Institute of Technology (IIT) - Roorkee, Roorkee, India (b) OBR Center of Distributed and Mobile Computing, Department of Computer Science, University of Cincinnati, Cincinnati, OH 45221, United States Article History: Received 15 August 2006; Revised 9 April 2008; Accepted 4 August 2008

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.

The ATLAS TDAQ network consists of four separate Ethernet based networks which together total over 4000 ports with 200 edge switches and 6 multi-blade chassis switches at the core. System checks are invoked at every level of the installation. The full installation is described in different static databases. Tools are provided to automatically cross-check these for consistency. The configuration management is centralized: configuration files stored in a database are distributed to all devices and the actual settings are periodically verified. Monitoring systems are deployed to validate the connectivity, identify malfunctions and confirm the resources availability upon request from TDAQ control. Relevant operational statistics (e.g., port status and throughput) are continuously logged and made available to TDAQ control. Watches and alarms are set for dynamic threshold violations and the complete instantaneous status can be viewed at different levels of abstraction in a 3D fly-through. A tool-set has been developed to demonstrate aggregate achievable cross-sectional bandwidth for TDAQ-specific traffic profiles, as well as to analyze traffic flows and hot spot behaviour. Index Terms--3D visualization, distributed software development, network diagnostics, network management, network monitoring, real time systems.

This article describes the operation and performance parameters of the new integrated monitoring concepts for the supervision of optical access networks. This system will help operators in decreasing operational expenditures by detecting degradation of network components before the transmission system is affected and improve customer satisfaction.

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.

This paper describes a computer-supported collaborative learning (CSCL) case study in engineering education carried out within the context of a network management course. The case study shows that the use of two computing tools developed by the authors and based on free- and open-source software (FOSS) provide significant educational benefits over traditional engineering pedagogical approaches in terms of both concepts and engineering competencies acquisition. The Collage authoring tool guides and supports the course teacher in the process of authoring computer-interpretable representations (using the IMS Learning Design standard notation) of effective collaborative pedagogical designs. Besides, the Gridcole system supports the enactment of that design by guiding the students throughout the prescribed sequence of learning activities. The paper introduces the goals and context of the case study, elaborates on how Collage and Gridcole were employed, describes the applied evaluation methodology, and discusses the most significant findings derived from the case study. Index Terms--Authoring tool, case study, collaboration scripts, computer-supported collaborative learning (CSCL), free- and open-source software (FOSS), IMS Learning Design, learning management system.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2007.06.003 Byline: Roberto Cusani (a), Tiziano Inzerilli (a), Luca Valentini (b) Keywords: Network performance; KPI; Channel quality; UMTS; HSDPA Abstract: Monitoring network performance and status is a fundamental task for network operators as it directly impacts the quality of the offered services and hence user satisfaction. For this purpose a consolidated approach, which is largely adopted by network operators, is based on the so-called KPIs (key performance indicators). In this paper, we propose and discuss a set of KPIs to monitor network performance of the new HSDPA enhanced UMTS infrastructure. KPI statistics are collected and analysed from the novel HSDPA network of H3G, one of the major Italian mobile network operators. Author Affiliation: (a) Sapienza Universita di Roma, Via Eudossiana 18, 00184 Rome, Italy (b) H3G S.p.A., Via Alessandro Severo n. 246, 00145 Rome, Italy Article History: Received 10 September 2006; Revised 23 May 2007; Accepted 13 June 2007 Article Note: (miscellaneous) Responsible Editor: C. Westphal

A practical mobility management technique aimed at reducing handoff latency to less than 10ms has been proposed and implemented in this paper. Handoff latency has been reduced by decoupling scanning from handoff execution process. This scheme has been implemented in the form of client side application with modifications to open source Madwifi new generation driver. Performance of this mobility management scheme has been evaluated on experimental Testbed for finding its suitability for real time applications. Effect of the proposed scheme on commercial VoIP client, Skype has been evaluated. Effect of the proposed handoff and optimized background scan on audio and video streaming has also been investigated. The results indicate that this mobility management technique can be used for real time traffic over 802.11 wireless networks. Key words: VoIP, Darwin Streaming Server, Handoff, Background Scanning, INTRODUCTION In recent years there has been an explosive growth in the use of wireless local area networks arising from the advent of the IEEE 802.11b standards(1). Service providers have [...]

This paper proposes a joint power and rate assignment (JPRA) algorithm to deal with multirate soft handoffs (SHOs) in mixed-size wideband code division multiple access cellular systems. This JPRA algorithm contains a link proportional power allocation scheme and an evolutionary computing rate assignment method to determine an appropriate allocation of transmission power and service rate for multirate SHOs. It can achieve power balancing among cells better than the conventional site-selection diversity transmission scheme with best effort rate allocation. Simulation results show that the JPRA algorithm can achieve better cell's service coverage and higher system capacity with and without the measurement errors during the active set selection. Index Terms--CDMA, optimization methods, resource management, soft handoff.

Abstract In this paper, we address the problem of optimal distribution of computational tasks on a network of heterogeneous computers when one or more tasks do not fit into the […]

A study on evaluating network reliability identifies minimal cut tool in systems design and control.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2006.04.018 Byline: K.G. Anagnostakis (a), M.B. Greenwald (c), S. Ioannidis (d), D. Li (b), J.M. Smith (b) Keywords: Active networks; Network monitoring; Network measurement; Worm detection Abstract: Increases in scale, complexity, dependency and security for networks have motivated increased automation of activities such as network monitoring. We have employed technology derived from active networking research to develop a series of network monitoring systems, but unlike most previous work, made application needs the priority over infrastructure properties. This choice has produced the following results: (1) the techniques for general infrastructure are both applicable and portable to specific applications such as network monitoring; (2) tradeoffs can benefit our applications while preserving considerable flexibility; and (3) careful engineering allows applications with open architectures to perform competitively with custom-built static implementations. These results are demonstrated via measurements of the lightweight active measurement environment (LAME), its successor, flexible LAME (FLAME), and their application to monitoring for performance and security. Author Affiliation: (a) Institute for Infocomm Research, 21 Heng Mui Keng Terrace, Singapore 119613, Singapore (b) Distributed Systems Laboratory, CIS Department, University of Pennsylvania, 200 S. 33rd Street, Philadelphia, PA 19104, USA (c) Bell Labs, 600 Mountain Avenue, Murray Hill, NJ 07974, USA (d) CS Department, Stevens Institute of Technology, Hoboken, NJ 07030, USA

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