The problem of real time control of robot manipulators in the presence of obstacles is considered. In order to achieve high speeds of operation in addition to obstacle avoidance, actuator dynamics and noise are modelled and added to the system description. The Obstacle Avoidance Strategy (OAS) translates each state constraint (obstacle) into state dependent control constraints (SDCC), which take the form of hyperplanes in the control space. The intersection of the sets defining the SDCC and the hard control bounds form a polygon in the control space. The Optimal Decision Stragety (ODS) is then used to calculate the control which lies in this polygon and minimizes the deviation between the acceleration vector of the CCR and a desired field of accelerations. Although the OAS algorithm is developed for a Cartesian Coordinate Robot (CCR), its approach can be utilized for articulated coordinate robots. Simulation results display the effectiveness of the algorithm for a workspace hosting multiple obstacles. The simplicity of the algorithm makes it desirable for real time control.

To support the North Carolina Information Highway network and its services, GTE has developed new capabilities for the integrated management of broadband networks. These include: functionally integrated network management, enabling GTE to monitor and control ATM, SONET, and other related networks in real time, these capabilities are provided by the TelOps Network Integrated Control System (TONICS); and automated service management, enabling GTE to provide service-level configuration and fault management for new broadband services, these capabilities are provided by the broadband service management system (BSMS). Together, TONICS and BSMS provide a complete and integrated solution for managing broadband networks such as the NCIH.

The Network Management and Control Simulator (NEMACS) is a software tool for developing, testing, integrating and evaluating different network management (NM) techniques for multiservice circuit switched networks. NEMACS is designed to provide the modeling detail and flexibility required for research and development work in NM. NEMACS models network elements, signaling protocols, and exogenous network events to a level of detail sufficient for capturing network behavior pertinent to NM. Logical layering of call transport, call control, and network control functions in NEMACS provides flexibility in composition of both network scenarios and their respective NM strategies.

Government communications networks are evolving very rapidly into multiservice integrated communication networks. At such they are converging with public and private networks both at the level of the technologies they use and in terms of the high level of interoperability between public/government networks that will be necessary in the near future. This paper reports on a testbed that explores new technologies to meet the future network operations and management requirements of government networks.

The authors briefly overview the basic characteristics of legacy network management systems used in telephone operating companies (telcos) and highlight their deficiencies for the emerging network. They further propose a network management methodology for supporting both the embedded base and the new generation of network technologies and services. The proposed approach differs from earlier network management methodologies in three major ways: it is driven by managing service performance and network robustness, rather than managing network equipment; it is based on a global network model that makes “end-to-end” management possible, in contrast to today's highly segmented management; and its decision support and automated applications are “network-state” dependent as opposed to being solely driven by “raw” network measurements

The authors present a scheme for optimal real-time bandwidth allocation and path restorations in a mesh network via SONET WDCS (wideband digital cross-connect system) in response to demand dynamics and to link and/or node failure(s). The scheme dynamically maximizes network throughput while ensuring full service restorability. In this process, the scheme integrates the dynamics of demand admission, bandwidth allocation, and spare capacity assignment. Since the physical network capacity is limited, not all the demand can be accommodated under the full restorability requirement. The demand which cannot be allocated under this requirement should be rejected at the network boundary. In the scheme, the optimal spare capacity assignment is just a consequence of the optimal network admission and optimal fully restorable bandwidth allocation. The authors also present an efficient parallel algorithm for optimal solution of the joint demand admission and restorable bandwidth allocation problem. The algorithm is suitable for real-time optimization in large networks

A decentralized, state-dependent access-control and routing strategy for circuit-switched networks is presented. To decentralize the control, the network is partitioned into subnets and a specific traffic controller is assigned to each one. The controllers obtain periodic subnet measurements, and compute the optimal control policy through an iterative and parallel dialog with other controllers. The following objectives for traffic control are considered. First, to allocate the incoming demand, maximizing the predicted minimum trunk group residual capacity over the network. Secondly, when the projected demand cannot be accommodated, optimal strategy should reject fairly the extra demand at source. The mathematical formulation of the above objectives leads to an equilibrium programming problem (EPP). It is shown that the EPP can be decomposed into a number of subproblems solved in parallel by the intercommunicating controllers

A performance management scheme is introduced to satisfy end-to-end performance requirements of multiclass services, using a nested control scheme. The network-level controller periodically computes an optimal bandwidth allocation policy for the entire network, and downloads parameters to the call- and packet-level controllers to regulate network traffic accordingly. The call-level controller limits SONET (synchronous optical network) pipe fills, exercises access-control fairly across source destination pairs, and is based on profitability across call classes. The packet-level controller provides congestion-free high-speed data transmission within the SONET pipes designated and realized by the network and call controllers, respectively

A novel approach is suggested to the problem of obstacle avoidance for a point robot moving among circular or elliptical/spherical or ellipsoid obstacles. The obstacle avoidance strategy (OAS) translates each state constraint (obstacle) into a state-dependent control constraint (SDCC). Each SDCC defines a hyperplane in the control space u. The intersection of the SDCC sets with the hard control bounds forms a polygon in u. The optimal decision strategy (ODS) control algorithm is then used to find the control which lies in this polygon-assuring obstacle avoidance-and minimizes the deviation between the acceleration vector of the point robot and a desired acceleration field. Simulation results display the effectiveness of the algorithm for a workspace hosting multiple obstacles. The OAS algorithm has been implemented successfully on a small Cartesian-coordinate robot

The joint access-control and routing problem for distributed networks is formulated as an equilibrium programming problem (EPP). The strategy, for an upcoming control period, decreases call blocking and balances network load by maximizing network residual capacity, and fairly rejects at the source the source-destination demands that are expected to exceed network capacity. The EPP formulation allows for both decentralized implementation of the joint access control and routing problem and massive parallelization of the optimization procedure to satisfy real-time requirements. The computational complexity of the algorithm decreases proportionally with the number of processors used. The convergence of the decentralized algorithm to the network-wide optimum is proved. Compared to the case where subnet EPPs are solved independently by each controller, simulation results show significantly better utilization of network resources when subnet controllers jointly solve the network-wide EPP. Performance analysis of the algorithm and numerical studies show that the algorithm is well suited for real-time implementation in large networks or internetworks

This paper presents a new scheme for real-time bandwidth allocation and path restoration (BARS) in mesh networks via SONET wideband digital cross-connect systems (WDCSs) in response to demand and load dynamics and link and/or node failure(s). The scheme dynamically maximizes bandwidth allocation while ensuring full service restorability. Since the physical network capacity is limited, sometime not all the demand can be accommodated under the full restorability requirement. This demand in SONET BARS is rejected fairly at the network boundary even if capacity for allocation is available. Bandwidth allocation and fair demand admission are optimized jointly under the full restorability requirements. The implementation of SONET WDCS does not need excessive storage. An efficient parallel algorithm for solving the optimization problem is also presented. The algorithm produces superior spare capacity assignments compared to the results in the literature

The problem of real time robust control of robot manipulators in the presence of obstacles is considered. In order to achieve high speeds of operation in addition to obstacle avoidance, actuator dynamics and noise are modelled and added to the system description. The Obstacle Avoidance Strategy (OAS) translates each state constraint (obstacle) into state dependent control constraints (SDCC), which take the form of hyperplanes in the control space. The intersection of the sets defining the SDCC and the hard control bounds form a polygon in the control space. The Optimal Decision Stragety (ODS) is then used to calculate the control which lies in this polygon and minimizes the deviation between the acceleration vector of the CCR and a desired field of accelerations. Although the OAS algorithm is developed for a Cartesian Coordinate Robot (CCR), its approach can be utilized for articulated coordinate robots. Simulation results display the effectiveness of the algorithm for a workspace hosting multiple obstacles. The simplicity of the algorithm makes it desirable for real time control.

The emerging interactive video dial tone (VDT) services pose some unique requirements for real-time network monitoring and control. To support the roll-out of VDT-based networks and services, GTE is developing new network management applications on its TONICS (Telephone Operations Network Integrated Control System) platform. TONICS's applications are embedded in a high availability software platform providing distributed processing. The article describes the real-time management requirements of VDT networks, provides an overview of the TONICS integration platform, outlines a network management and control architecture for VDT networks, illustrates example VDT management applications, and discusses the deployment issues.

A network management and control simulator (NEMACS) software testbed for developing, testing, and integrating different network management (NM) techniques for multiservice circuit-switched networks is discussed. NEMACS is capable of applying different NM strategies to a plethora of simulated network scenarios that include networks of differing size, speed, transport topology, control, and management architectures. NEMACS simulates networks by modeling the behavior of various network modules: call transport modules (CTMs), call control modules (CCMs), and network control modules (NCMs). The implementation of NEMACS software and four examples of how NEMACS has been used to rapidly prototype NM techniques are presented. The examples deal with focused overload in a simple network, predictive access-control and routing strategy, decentralized management, and multiclass traffic control.