In both vertically integrated and restructured power systems, it is desired to transmit power to every parts of the network without any limits resulted from congestion and consequently avoiding inefficiency in generat...
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ISBN:
(纸本)9781424487790
In both vertically integrated and restructured power systems, it is desired to transmit power to every parts of the network without any limits resulted from congestion and consequently avoiding inefficiency in generation dispatch. In this paper, in order to eliminate power system's congestion, distributed generation (DG) is employed. DG's have nonlinear impacts on the power system characteristics such as, the power transmitted between two locations of the network. Hence for identifying the impacts of DG on system variables, the problem of DG's sizing and placement is formulated as an AC optimal power flow (ACOPF) with binary variables and is solved by using mixed integer programming (MIP). In order to test the feasibility of mentioned method, the IEEE-14 bus systems has been used and also to study the impacts of DG's on this system, a number of system variables have been studied including: generation cost, congestion rent, locational marginal price (LMP), voltage profile and transmission losses.
The original formal problem definition of financial management optimization of an enterprise at this conjuncture of financing the state defense order is suggested. The problem is shown to belong to the class of NP-har...
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ISBN:
(纸本)9781509040704
The original formal problem definition of financial management optimization of an enterprise at this conjuncture of financing the state defense order is suggested. The problem is shown to belong to the class of NP-hard problems of the mixedprogramming. The existing methods for solving this problem are considered and the properties of the program tools developed by the authors for searching for the best solutions are discussed.
Maximization of network lifetime is one of the most important design goals in Wireless Sensor Networks (WSNs). In WSNs with static base stations, sensor nodes close to the base station dissipate most of their energies...
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ISBN:
(纸本)9781467362337
Maximization of network lifetime is one of the most important design goals in Wireless Sensor Networks (WSNs). In WSNs with static base stations, sensor nodes close to the base station dissipate most of their energies for relaying other sensor nodes' data. Although cooperation among the sensor nodes results in longer network lifetimes in comparison to greedy approaches, there is an inherent limit on the achievable network lifetime due to the limited energy of the sensor nodes in close proximity of the base station acting as relays. Base station mobility is proposed as a remedy for the WSN hot spot problem. As the base station relocates, the burden of relaying the data coming from all sensor nodes can be shared by a larger set of nodes. To take advantage of base station mobility to maximize the network lifetime, determining the optimal mobility pattern is of utmost importance. In this study, we investigate the impact of using three base station mobility patterns which are random mobility, grid mobility, and spiral mobility. To avoid the shadowing effects of specific protocols or algorithms we build a novel mixed integer programming (MIP) framework which enables us to explore the design space under optimal operating conditions.
In power systems, demand and supply always have to be balanced. This is becoming more challenging due to the sustained penetration of renewable energy sources and their inherit uncertain production. Because of the inc...
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In power systems, demand and supply always have to be balanced. This is becoming more challenging due to the sustained penetration of renewable energy sources and their inherit uncertain production. Because of the increasing amount of electrical vehicles (EVs), and the high capacity and flexibility of their charging process, EVs are a good candidate for providing balancing services to electric systems. We propose a stochastic optimization method for an EV aggregator that models the uncertainty of the imbalance price, the reserve prices and the probability of acceptance and deployment of reserves. The model results in an optimal charging and discharging strategy considering dayahead purchase, imbalance trading and reserve bids. Unlike previous studies, the reserve bids consists of both a quantity and an optimal price using a novel efficient formulation for the price bids. Experimental evaluation shows that the proposed stochastic opti-mization method results in lower costs than determin-istic and quantity-only bid solutions.
Supply uncertainty can have a very radical impact on firms who fail to protect against it. It appears that the quantity delivered by the supplier is random. In this paper, we develop a mixedinteger non linear program...
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ISBN:
(纸本)9781467358125
Supply uncertainty can have a very radical impact on firms who fail to protect against it. It appears that the quantity delivered by the supplier is random. In this paper, we develop a mixedinteger non linear programming model for a mono-item multi-period inventory management decision and supplier selection problem under random yield. The yield of supplier is random. The buyer needs to answer three questions: how much to command? what is supplier selected? and in which period? The complexity of this problem is NP-hard. We used a genetic algorithm (GA) to solve this problem.
We propose a mathematical formulation for the problem of scheduling the movements of an autonomous heliostat in order to track the sun. We make use of a mixed integer programming model where the main objective is mini...
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ISBN:
(纸本)9781467356688
We propose a mathematical formulation for the problem of scheduling the movements of an autonomous heliostat in order to track the sun. We make use of a mixed integer programming model where the main objective is minimizing the total energy consumption. The formulation considers the tradeoff between minimizing de energy consumption and minimizing the heliostat position deviations and guarantees the quality of the beam reflected in the central tower. We also propose a linear model to define a suitable size of the energy supply system that feeds the heliostat. Numerical results are presented for two different daily schedules. The potentiality of the method is demonstrated through comparison results with traditional solutions.
A microgrid for the purpose of reducing the fuel consumption at the Japanese Showa Base in the Antarctica is being considered due to the increase in fuel consumption in the base caused by the continuous increment in r...
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ISBN:
(纸本)9781479999835
A microgrid for the purpose of reducing the fuel consumption at the Japanese Showa Base in the Antarctica is being considered due to the increase in fuel consumption in the base caused by the continuous increment in research activities. In this paper, the planning of the operation of the engine generators at a representative day using a simplified mixed integer programming is proposed for this microgrid.
A typical microgrid consists of local power plants, renewable sources, energy storage systems, loads and communication units. It is designed to be operated autonomously or attached to a main utility grid, recognized a...
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ISBN:
(纸本)9781538614280
A typical microgrid consists of local power plants, renewable sources, energy storage systems, loads and communication units. It is designed to be operated autonomously or attached to a main utility grid, recognized as a promising application for energy system integration. This paper studies the optimal energy scheduling problem in microgrids which minimizes the total operational cost, subjecting to a number of operational and technical constraints. The proposed simulation framework is compacted to a mixed logical dynamical system which has advantages in terms of computational efficiency, compared with heuristic-based models. A case study of the optimal scheduling is performed on a centralized microgrid, and result shows the effectiveness of the proposed model in both grid-connected and islanded modes.
The difficulty in allocating virtual machines (VMs) on servers stems from the requirement that sufficient resources (such as CPU capacity and network bandwidth) must be available for each VM in the event of a failure ...
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ISBN:
(纸本)9781467359443
The difficulty in allocating virtual machines (VMs) on servers stems from the requirement that sufficient resources (such as CPU capacity and network bandwidth) must be available for each VM in the event of a failure or maintenance work as well as for temporal fluctuations of resource demands, which often exhibit periodic patterns. We propose a mixed integer programming approach that considers the fluctuations of the resource demands for optimal and dependable allocation of VMs. At the heart of the approach are techniques for optimally partitioning the time-horizon into intervals of variable lengths and for reliably estimating the resource demands in each interval. We show that our new approach allocates VMs successfully in a cloud computing environment in a financial company, where the dependability requirement is strict and there are various types of VMs exist.
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