Patent application number | Description | Published |
20080198004 | Method for equitable placement of a limited number of sensors for wide area surveillance - A limited number of sensors are placed at selected locations in order to achieve equitable coverage levels to all locations that need to be monitored. The coverage level provided to any specific location depends on all sensors that monitor the location and on the properties of the sensors, including probability of object detection and probability of false alarm. These probabilities may depend on the monitoring and monitored locations. An equitable coverage to all locations is obtained by finding the lexicographically largest vector of coverage levels, where these coverage levels are sorted in a non-decreasing order. The method generates a lexicographic maximin optimization model whose solution provides equitable coverage levels. In order to facilitate computations, a nonlinear integer optimization model is generated whose solution provides the same coverage levels as the lexicographic maximin optimization model. Solution of the nonlinear integer optimization model is obtained through the adaptation of known optimization methods. | 08-21-2008 |
20080279141 | Methods for optimal multi-channel assignments in vehicular ad-hoc networks - A communications path is established among an ordered sequence of moving nodes, representing vehicles. Available channels may differ from one node to the next node and a node cannot use the same channel for both receiving and transmitting information. Three methods are described that provide an optimal sequence of channel assignments between the nodes. A sequence of channel assignments is called optimal if it establishes a communications path from the first node in the sequence to the last node in the sequence, or, if such a path does not exist, from the first node to the farthest node possible in the sequence. The first method uses a depth-first search starting from the first node in the sequence. The second method uses a “look ahead” scheme in the depth-first search method. The third method requires only a single pass through the sequence of nodes by identifying optimal channel assignments in subsequences of nodes without a need for backtracking. | 11-13-2008 |
20090213875 | Method for Equitable Bandwidth Allocation for Content Distribution Networks - A method is presented for determining bandwidth allocations in a content distribution network that comprises multiple trees, where the root of each tree has a server that broadcasts multiple programs throughout the tree. Each network link has limited capacity and may be used by one or more of these trees. The allocation problem is formulated as an equitable resource allocation problem with a lexicographic maximin objective function that attempts to provide equitable service performance for all requested programs at the various nodes. The constraints include link capacity constraints and tree-like ordering constraints imposed on each of the programs. The algorithm provides an equitable solution in polynomial time for wide classes of performance functions. At each iteration, the algorithm solves single-link maximin optimization problems while relaxing the ordering constraints, selects a bottleneck link and fixes various variables at their optimal value. | 08-27-2009 |
20100111104 | BANDWIDTH ALLOCATION FOR VIDEO-ON-DEMAND NETWORKS - Methods for the optimal allocation of bandwidth among a plurality of video-on-demand (VOD) programs available on each link of a VOD tree network, where a server at the root node of the tree network broadcasts the multiple VOD programs. Each node in the network has demands for a subset of the programs and each link connecting nodes in the network has a limited amount of available bandwidth capacity. The available bandwidth is allocated on each link optimally among all programs that are carried on that link. The bandwidth allocated to a specific program may be different on different links of the network, as the bandwidth allocated may be decreased, but not increased, from one link to the next along the paths from the root node to the destination nodes. The methods use equitable resource allocation models with a lexicographic minimax objective function. The first method finds optimal solutions while satisfying the capacity constraints on all links, tree-like ordering constraints for the bandwidth allocated to each of the programs, and lower and upper bounds on bandwidth allocation for each program. The second method finds optimal solutions to a more restrictive scheme that imposes additional constraints which require equal bandwidth allocation for a specific program on all relevant links emanating from the same node. | 05-06-2010 |
20100192013 | System and Method for Automated Distributed Diagnostics for Networks - A method for distributed computations for fault-diagnosis in a system whose fault propagation model has deterministic couplings between faults and symptoms includes creating a ‘relation graph’ in which the nodes correspond to the potential faults, with two nodes connected by a ‘relational link’ if their corresponding faults have an observed symptom in common. The relation graph is then partitioned into several domains, while minimizing the number of cross-domain relational links, which correspond to cross-domain symptoms. In each domain, all the optimal local solutions to the domain's sub-problem are first determined, and then a combination is selected of the local solutions, one from each domain, that explains the maximum number of cross-domain symptoms, where the optimal solution is supplemented, if necessary, with additional faults to explain any remaining unexplained cross-domain symptoms, determining also a bound on the deviation from optimality of the global solution. | 07-29-2010 |
20100209099 | Network Restoration Under Link or Node Failure Using Preconfigured Virtual Cycles - The design of telecommunication networks is such that there is provision of end-to-end path protection to multiple demands under a single link or node failure in the networks. Restoration routes are provided on Preconfigured Virtual Cycles (PVC's), where each demand is assigned one restoration route and specific restoration wavelengths on a segment of one cycle. Multiple demands may share restoration wavelengths, and the number of restoration wavelengths may vary among the PVC links. First, a plurality of candidate PVC's are generated where each demand may be assigned to multiple candidates. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PVC. Next, a set of PVC's is selected from among the candidates, while minimizing total reserved restoration capacity and ensuring that all demands are protected. Next duplicate assignments are eliminated. Finally, conflicts of wavelength assignments are resolved. The invention focuses primarily on optical networks. | 08-19-2010 |
20110064404 | Network Restoration Under Dual Failures Using Path Protecting Preconfigured Cycles - The design of optical telecommunication networks is such that there is provision of end-to-end path restoration to specified demands under up to two links or nodes failures. Restoration routes are provided on Path Protecting Preconfigured Cycles (PP-PCs), where each demand is assigned one or two restoration routes and restoration wavelengths on a segment of one cycle. Splitting of demand across multiple restoration routes is not allowed. All restoration routes and restoration wavelengths are predetermined where multiple demands may share restoration wavelengths without resorting to intermediate switching or wavelength conversions along restoration routes. First, numerous candidate PP-PCs are generated. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PP-PC. Next, a set of PP-PCs is selected from among the candidates, while minimizing total reserved restoration wavelengths cost and ensuring that all demands are protected as required. Finally, conflicts of wavelength assignments are resolved. | 03-17-2011 |
20110261703 | DISTRIBUTED METHOD FOR EQUITABLE BANDWIDTH ALLOCATION FOR CONTENT DISTRIBUTION IN A NETWORK - A distributed method is presented for determining equitable bandwidth allocations in a content distribution tree network, where the root of the tree has a server that broadcasts multiple programs throughout the tree. The intensive computations in the distributed method are done at each of the nodes independently while only minimal information is exchanged among the nodes. Each network link has limited capacity. The allocation problem is formulated as an equitable resource allocation problem with a lexicographic maximin objective function that provides equitable service performance for all requested programs at the various nodes. The constraints include link capacity constraints and tree-like ordering constraints imposed on each of the programs. The distributed method converges to the equitable solution in a finite number of iterations. The distributed method can be applied to a network comprised of multiple trees. | 10-27-2011 |
20120328282 | Network Restoration Under Link or Node Failure Using Preconfigured Virtual Cycles - The design of telecommunication networks is such that there is provision of end-to-end path protection to multiple demands under a single link or node failure in the networks. Restoration routes are provided on Preconfigured Virtual Cycles (PVC's), where each demand is assigned one restoration route and specific restoration wavelengths on a segment of one cycle. Multiple demands may share restoration wavelengths, and the number of restoration wavelengths may vary among the PVC links. First, a plurality of candidate PVC's are generated where each demand may be assigned to multiple candidates. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PVC. Next, a set of PVC's is selected from among the candidates, while minimizing total reserved restoration capacity and ensuring that all demands are protected. Next duplicate assignments are eliminated. Finally, conflicts of wavelength assignments are resolved. The invention focuses primarily on optical networks. | 12-27-2012 |
20130055020 | Method for Automated Distributed Diagnostics for Networks - A method for distributed computations for fault-diagnosis in a system whose fault propagation model has deterministic couplings between faults and symptoms includes creating a ‘relation graph’ in which the nodes correspond to the potential faults, with two nodes connected by a ‘relational link’ if their corresponding faults have an observed symptom in common. Each relational link is assigned a weight equal to the sum, taken over the symptoms represented by the relational link, of the reciprocal of the number of distinct fault-pairs that produce each such symptom. The relation graph is then partitioned into several domains, while minimizing the number of cross-domain relational links, which correspond to cross-domain symptoms. In each domain, all the optimal local solutions to the domain's sub-problem are first determined, and then a combination is selected of the local solutions, one from each domain, that explains the maximum number of cross-domain symptoms, where the optimal solution is supplemented, if necessary, with additional faults to explain any remaining unexplained cross-domain symptoms, determining also a bound on the deviation from optimality of the global solution. | 02-28-2013 |