MPLS (multiprotocol label switching) over WDM (wavelength division multiplexing) networks are gaining significant attention due to the efficiency in resource utilization that can be achieved by jointly considering the...
详细信息
MPLS (multiprotocol label switching) over WDM (wavelength division multiplexing) networks are gaining significant attention due to the efficiency in resource utilization that can be achieved by jointly considering the two network layers. This paper addresses the design of MPLS over WDM networks, where some of the WDM nodes may not have packet switching capabilities. Given the WDM network topology and the offered traffic matrix, which includes the location of the edge LSRs (label switched routers), we jointly determine the location of the core LSRs (i.e. the core WDM nodes that also need to include packet switching capabilities) and the lightpath routes (which are terminated on the LSRs) that minimize the total network cost. We consider constraints both at the optical and packet layers: an MPLS hop constraint on the maximum number of LSRs traversed by each LSP (label switched path), which guarantees a given packet level QoS, and a WDM path constraint on the maximum length of lightpaths, which accommodates the optical transmission impairments. A novel integer linear programming (ILP) formulation based on an hop-indexed approach, which we call the HOP model, is proposed. A two-phase heuristic, derived from a decomposition of the HOP model in two simpler ILP models that are solved sequentially, is also developed. The computational results show that the heuristic is efficient and produces good quality solutions, as assessed by the lower bounds computed from the HOP model. In some cases, the optimal solution is obtained with the branch-and-bound method.
We derive asymptotic formulas with a secondary term for the (smoothly weighted) count of number of integer solutions of height 6 B with local conditions to the equation F (x1, x2, x3) = m, where F is a non-degenerate ...
详细信息
An improved particle swarm optimization approach is introduced in this paper, the improvements involves the dasiaworstpsila particlepsilas impact on the particles in addition to that of the dasiabestpsila one. Meanwhi...
详细信息
An improved particle swarm optimization approach is introduced in this paper, the improvements involves the dasiaworstpsila particlepsilas impact on the particles in addition to that of the dasiabestpsila one. Meanwhile, a self-adaptive inertia weight is adopted to enhance the performance of the approach. With nonlinear constraints handled by a penalty function, the proposed approach is applied to solve the short-term hydro scheduling of an example hydro system, the proposed approach shows a higher performance and obtains promising results compared to the standard particle swarm optimization and other methods of previous researches.
For a given polyhedral convex set-valued mapping we define a polyhedral convex cone which we call the natural ordering cone. We show that the solution behavior of a polyhedral convex set optimization problem can be ch...
详细信息
Autonomous aerial refueling (AAR) is an important capability for the future successful deployment and operation of unmanned aerial vehicles (UAVs), so it is necessary to design an efficient rendezvous scheduling appro...
详细信息
ISBN:
(纸本)9781665426480
Autonomous aerial refueling (AAR) is an important capability for the future successful deployment and operation of unmanned aerial vehicles (UAVs), so it is necessary to design an efficient rendezvous scheduling approach. In this paper, a general strategy for refueling missions is proposed for intensive refueling firstly, and then the tanker flight path and virtual queue sequence points are designed. Secondly, to obtain the optimal refueling time under the strategy, an integer linear programming (ILP) algorithm based on the branch-and-bound method is proposed, and some planning is further made for the waiting queue adjustment. Finally, the effectiveness of the proposed approach is demonstrated by simulation via two indexes, namely, the minimum oil volume and average volume of the receivers at the start of the refueling.
The p-cycle design problem has been extensively studied because it can provide both ring-like fast self-protection speed and spare capacity efficiency of path protection scheme. However, p-cycle provisioning for dynam...
详细信息
The p-cycle design problem has been extensively studied because it can provide both ring-like fast self-protection speed and spare capacity efficiency of path protection scheme. However, p-cycle provisioning for dynamic traffic has not been fully addressed. Most related works have not considered link capacity in the construction of p-cycles, which may cause problems in practice because the protection paths may not have enough backup bandwidth. In this paper, with the consideration of link capacity, we present a sufficient and necessary condition that guarantees p-cycles for providing enough protection bandwidth. Based on this condition, we propose an effective solution to provide connections for dynamic requests with the property that each link used for a connection is protected by a p-cycle. Simulation results show that our dynamic p-cycle provisioning solution outperforms the traditional path protection scheme.
In this paper we propose variable voltage task scheduling algorithms (periodic as well as aperiodic) that minimize energy. We first apply the existing task scheduling algorithms to obtain a feasible schedule and then ...
详细信息
In this paper we propose variable voltage task scheduling algorithms (periodic as well as aperiodic) that minimize energy. We first apply the existing task scheduling algorithms to obtain a feasible schedule and then distribute the available slack using an iterative algorithm that satisfies the theoretically obtained relation for minimum energy. We show experimentally that the voltage assignment obtained by our algorithm is very close (0.1% error) to that of the optimal assignment.
Equipping each node with multiple radios can substantially increase the capacity of wireless mesh networks, because in that way neighbor links can be assigned distinct channels to avoid interference. However, the aggr...
详细信息
Equipping each node with multiple radios can substantially increase the capacity of wireless mesh networks, because in that way neighbor links can be assigned distinct channels to avoid interference. However, the aggregate network interference still may not be sufficiently reduced due to a rough channel assignment. This paper focuses on the static channel assignment issue of multi-radio multi-channel wireless mesh networks. We propose an integer quadratic programming (IQP) model to minimize the average network interference and use this model to study the impact of radio and channel constraints. Our model considers different data transfer rates of distinct links and simulation results show it can effectively reduce the network interference. Simulation results also reveal that equipping each node with small number of radios might be sufficient for reducing the network interference, which provides a guideline of radio equipment in such networks.
We propose an adaptive bit and power allocation technique for an orthogonal frequency division multiple access based cognitive radio network. The resources are allocated such that each secondary user attains equal dat...
详细信息
We propose an adaptive bit and power allocation technique for an orthogonal frequency division multiple access based cognitive radio network. The resources are allocated such that each secondary user attains equal data rate while ensuring the interference leakage to the primary users is below a specific threshold. integer linear programming based optimal algorithm and a suboptimal method based on greedy algorithm have been proposed. integer linear programming based optimal method is of high complexity whilst the suboptimal method has a lower complexity and performs closer to the optimal method. The simulation results are provided to compare the performance of the suboptimal method with that of the optimal method.
Let G be a graph of order n. For a positive integer p, G is said to be a Wp graph if n ≥ p and every p pairwise disjoint independent sets of G are contained within p pairwise disjoint maximum independent sets. In thi...
详细信息
暂无评论