We propose an optimization approach to flow control where the objective is maximize aggregate source utility over their transmission rates. view network links and sources as processors of a distributed computation system solve dual problem using gradient projection algorithm. In this system, select rates that own benefits, minus bandwidth cost, adjust prices coordinate sources' decisions. allow feedback delays be different, substantial, time varying, update at different times with...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Network protocols in layered architectures have historically been obtained on an <emphasis emphasistype="boldital">ad hoc</emphasis> basis, and many of the recent cross-layer designs are also conducted through piecemeal approaches. protocol stacks may instead be holistically analyzed systematically designed as distributed solutions to some global optimization problems. This paper presents a...

We propose a branch flow model for the analysis and optimization of mesh as well radial networks. The leads to new approach solving optimal power (OPF) that consists two relaxation steps. first step eliminates voltage current angles second approximates resulting problem by conic program can be solved efficiently. For networks, we prove both steps are always exact, provided there no upper bounds on loads. is exact but angle may not provide simple way determine if relaxed solution globally...

The optimal power flow (OPF) problem is nonconvex and generally hard to solve. In this paper, we propose a semidefinite programming (SDP) optimization, which the dual of an equivalent form OPF problem. A global optimum solution can be retrieved from convex whenever duality gap zero. necessary sufficient condition provided in paper guarantee existence no for This satisfied by standard IEEE benchmark systems with 14, 30, 57, 118, 300 buses as well several randomly generated systems. Since...

Historically, centrally computed algorithms have been the primary means of power system optimization and control. With increasing penetrations distributed energy resources requiring control systems with many controllable devices, subject significant research interest. This paper surveys literature applications to systems. In particular, this reviews for offline solution optimal flow (OPF) problems as well online real-time OPF, frequency control, voltage wide-area problems.

We describe a new active queue management scheme, random exponential marking (REM), that aims to achieve both high utilization and negligible loss delay in simple scalable manner. The key idea is decouple the congestion measure from performance such as loss, length, or delay. While indicates excess demand for bandwidth must track number of users, should be stabilized around their targets independent users. explain design rationale behind REM present simulation results its wireline wireless networks.

Demand side management will be a key component of future smart grid that can help reduce peak load and adapt elastic demand to fluctuating generations. In this paper, we consider households operate different appliances including PHEVs batteries propose response approach based on utility maximization. Each appliance provides certain benefit depending the pattern or volume power it consumes. household wishes optimally schedule its consumption so as maximize individual net subject various flow...

Motivated by the power-grid-side challenges in integration of electric vehicles, we propose a decentralized protocol for negotiating day-ahead charging schedules vehicles.The overall goal is to shift load due vehicles fill overnight electricity demand valley.In each iteration proposed protocol, choose their own profiles following day according price profile broadcast utility, and utility updates guide behavior.This guaranteed converge, irrespective specifications (e.g., maximum rate...

We describe FAST TCP, a new TCP congestion control algorithm for high-speed long-latency networks, from design to implementation. highlight the approach taken by address four difficulties which current implementation has at large windows. architecture and summarize some of algorithms implemented in our prototype. characterize its equilibrium stability properties. evaluate it experimentally terms throughput, fairness, stability, responsiveness

This article reviews the current transmission control protocol (TCP) congestion protocols and overviews recent advances that have brought analytical tools to this problem. We describe an optimization-based framework provides interpretation of various flow mechanisms, in particular, utility being optimized by protocol's equilibrium structure. also look at dynamics TCP employ linear models exhibit stability limitations predominant versions, despite certain built-in compensations for delay....

We propose a duality model of end-to-end congestion control and apply it to understanding the equilibrium properties TCP active queue management schemes. The basic idea is regard source rates as primal variables measures dual variables, distributed primal-dual algorithm over Internet maximize aggregate utility subject capacity constraints. iteration carried out by algorithms such Reno or Vegas, DropTail, RED REM. present these their generalizations, derive functions, study interaction.

This tutorial summarizes recent advances in the convex relaxation of optimal power flow (OPF) problem, focusing on structural properties rather than algorithms. Part I presents two models, formulates OPF and their relaxations each model, proves equivalence relations among them. II sufficient conditions under which are exact.

We describe FAST TCP, a new TCP congestion control algorithm for high-speed long-latency networks, from design to implementation. highlight the approach taken by address four difficulties, at both packet and flow levels, which current implementation has large windows. architecture characterize equilibrium stability properties of TCP. present experimental results comparing our first Linux prototype with Reno, HSTCP, STCP in terms throughput, fairness, stability, responsiveness. aims rapidly...

This paper considers jointly optimal design of crosslayer congestion control, routing and scheduling for ad hoc wireless networks.We first formulate the rate constraint using multicommodity flow variables, resource allocation in networks with fixed channels (or single-rate devices that can mask channel variations) as a utility maximization problem these constraints.By dual decomposition, naturally decomposes into three subproblems: interact through price.The global convergence property this...

Destination-based forwarding in traditional IP routers has not been able to take full advantage of multiple paths that frequently exist Internet service provider networks. As a result, the networks may operate efficiently, especially when traffic patterns are dynamic. This paper describes multipath adaptive engineering mechanism, called MATE, which is targeted for switched such as multiprotocol label switching (MPLS) The main goal MATE avoid network congestion by adaptively balancing load...

We present a systematic method to design ubiquitous continuous fast-acting distributed load control for primary frequency regulation in power networks, by formulating an optimal (OLC) problem where the objective is minimize aggregate cost of tracking operating point subject balance over network. prove that swing dynamics and branch flows, coupled with frequency-based control, serve as primal-dual algorithm solve OLC. establish global asymptotic stability multimachine network under such type...

Energy expenditure has become a significant fraction of data center operating costs. Recently, "geographical load balancing" been suggested to reduce energy cost by exploiting the electricity price differences across regions. However, this reduction can paradoxically increase total use.

The search for unifying properties of complex networks is popular, challenging, and important. For modeling approaches that focus on robustness fragility as concepts, the Internet an especially attractive case study, mainly because its applications are ubiquitous pervasive, widely available expositions exist at every level detail. Nevertheless, alternative to often make extremely different assumptions derive opposite conclusions about fundamental one same system. Fortunately, a detailed...

We show how an adaptive control algorithm can improve the performance of distributed reactive power in a radial distribution circuit with high penetration photovoltaic (PV) cells. The is designed to balance need for quality (voltage regulation) desire minimize loss. adaptation law determines whether objective function minimizes losses or voltage regulation based on at each node remains close enough substation. controlled through inverter PV signals are determined local instantaneous...

Distribution networks are usually multiphase and radial. To facilitate power flow computation optimization, two semidefinite programming (SDP) relaxations of the optimal problem a linear approximation proposed. We prove that first SDP relaxation is exact if only second one exact. Case studies show numerically obtains voltages within 0.0016 per unit their true values for IEEE 13, 34, 37, 123-bus real-world 2065-bus network.

This tutorial summarizes recent advances in the convex relaxation of optimal power flow (OPF) problem, focusing on structural properties rather than algorithms. Part I presents two models, formulates OPF and their relaxations each model, proves equivalence relations among them. II sufficient conditions under which are exact.

The intent of the study detailed in this paper is to demonstrate benefits inverter var control on a fast timescale mitigate rapid and large voltage fluctuations due high penetration photovoltaic generation resulting reverse power flow. Our approach formulate volt/var as radial optimal flow (OPF) problem minimize line losses energy consumption, subject constraints magnitudes. An efficient solution OPF presented used structure injection net benefits, taking into account additional cost when...

The optimal power flow (OPF) problem determines a network operating point that minimizes certain objective such as generation cost or loss. It is nonconvex. We prove global optimum of OPF can be obtained by solving second-order cone program, under mild condition after shrinking the feasible set slightly, for radial networks. checked priori, and holds IEEE 13, 34, 37, 123-bus networks two real-world

Motivated by the need to cope with rapid and random fluctuations of renewable generation, we presents a model that augments traditional Volt/VAR control through switched controllers on slow timescale inverter fast timescale. The optimization problem is generally nonconvex therefore hard solve. We propose simple convex relaxation prove it exact provided over-satisfaction load allowed. Hence over radial networks efficiently solvable. Simulations real-world distribution circuit illustrates...

In this paper, we consider two abstract market models for designing demand response to match power supply and shape demand, respectively. We characterize the resulting equilibria in competitive as well oligopolistic markets, propose distributed algorithms achieve equilibria. The serve a starting point include appliance-level details constraints practical schemes smart grids.