This article investigates the problem of robust decentralized load frequency control (LFC) in multiarea interconnection power systems, in the presence of the external disturbances and stochastic abrupt variations, such as component failures and different load demands. To capture the different operating conditions of the load in the multiarea power systems, a Markov superposition technique is skillfully employed to model the system's component matrices. To solve the Nash equilibrium solution of the zero-sum differential game problem, an improved online adaptive dynamic programming (ADP) algorithm based on the experience replay technique (ERT) is developed, which addresses the nonlinear coupling difficulties encountered in solving the game algebraic Riccati equations (Game AREs). The proposed algorithm weakens the condition that traditional policy iteration online solutions of zero-sum games require an initial stabilizing control policy pair, and considers the fact that only the transition probability matrix is known, while the prior knowledge of the dynamics is completely unknown. The algorithm is used to obtain both a minimum LFC and maximum disturbance policy for a given disturbance rejection level. Additionally, a safer LFC controller of the power systems with the Markov jumping parameters is designed. The stability and convergence of the proposed algorithm are demonstrated. Finally, the effectiveness and good performance of the proposed design method are validated using a two-area four-mode simulation example.

Many network design problems encompass two tasks, routing and resource allocation, that are so intricately intertwined as to contribute significantly to the intractability of such problems. In this paper, we make two contributions to addressing general network design problems of this nature. First, we present a new decomposition method that optimally decouples resource allocation from routing, making it possible to tackle each of these aspects separately. Second, we develop a recursive branch-and-bound algorithm to search the routing space exhaustively, yet in a scalable manner. We apply our method to a well-known intractable problem in optical networks, routing and spectrum assignment (RSA). Our results indicate that the recursive algorithm is able to search efficiently the entire routing space of topologies representative of large-scale wide area networks.

The routing and spectrum assignment (RSA) problem has emerged as the key design and control problem in elastic optical networks. Distance adaptive spectrum allocation exploits the tradeoff between spectrum width and reach to improve resource utilization by tailoring the modulation format to the level of impairments along the path. In this paper, we consider the distance-adaptive RSA (DA-RSA) problem with fixed alternate routing. We first show that the DA-RSA problem in networks of general topology is a special case of a well-studied multiprocessor scheduling problem. We then leverage insights from scheduling theory to (1) present new results regarding the complexity of the DA-RSA problem, and (2) build upon list scheduling concepts to develop a computationally efficient solution approach that is effective in utilizing the available spectrum resources.

In multilayer networks, protection can be accomplished in any of the layers. However, which layer to protect most remains an important problem. In this paper, we consider a three-layer with IP/MPLS-over-OTN-over-DWDM in which we consider an optimization modeling framework incorporating modularization of its capacity for protection in any layer. Our resulting study, conducted on two topologies, shows that the cost ratio of different layers is an important factor in answering this question, as well as the actual modular values of the capacity used. Furthermore, we found that the cost providing protection in the OTN layer is highly influenced by the network connectivity.

Distance adaptive spectrum allocation exploits the tradeoff between spectrum width and reach to improve resource utilization by tailoring the modulation format to the level of impairments along the path. We first show that the distance-adaptive routing and spectrum assignment (DA-RSA) problem in mesh networks is a special case of a multiprocessor scheduling problem. We then develop a suite of efficient and effective DA-RSA algorithms that build upon list scheduling concepts. Our work explores the tradeoffs involved in DA-RSA algorithm design, and opens up new research directions that may leverage the vast literature in scheduling theory.

Spectrum assignment has emerged as the key design and control problem in elastic optical networks. We have shown that spectrum assignment in networks of general topology is a special case of scheduling multiprocessor tasks on dedicated processors. Based on this insight, we develop and evaluate efficient and effective algorithms for mesh and chain networks that build upon list scheduling concepts.

Multilayer network design has received significant attention in current literature. Despite this, the explicit modeling of IP/MPLS over OTN over DWDM in which the OTN layer is specifically considered has not been addressed before. This architecture has been identified as promising that bridges integration and interaction between the IP and optical layers. In this paper, we present an integrated capacity optimization model for network planning of such multilayer networks that consider the OTN layer as a distinct layer with its unique technological sublayer constraints. We develop a heuristic algorithm to solve this model for large networks. Finally, we provide a detailed numeric study that considers various cost parameter values of each layer in the network. We analyze the impact of each layer's cost parameter values on neighboring layers and overall network cost.

In this work, we consider the performance benefits of distribution reservation control schemes in partially-connected wavelength-routed all-optical WDM networks. In particular, we propose a new distributed reservation control scheme designed to work for general topology wavelength-routed WDM networks. In this new scheme, capacity reservation is invoked by always using the first shortest path if the direct route does not exist between all node (demand) pairs. Through our study, we show that our proposed scheme in the presence of distributed adaptive routing is much more fair on pairwise blocking than the conventional reservation method in general topology wavelength-routed WDM networks, especially in the presence of wavelength converters and overload situations.