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An unconstrained optimization technique is presented for the phase-only synthesis of omnidirectional array patterns with multiple null regions from a circular array.
The popularity of Wi-Fi-enabled devices alongside the growing demand for non-licensed spectrum, has made the Wi-Fi networks exceedingly congested. This endangers the efficiency of Wi-Fi and negatively affect the users' experience. The problem is especially pressing in dense areas (e.g. shopping centers) where Wi-Fi channel assignment is more likely to be uncoordinated and the working environment of...
An increasing awareness of energy efficiency has led to the development of several improved converter topologies, semiconductor devices and control schemes for distributed energy resources, and, particularly, for microgrids. Recent advances in energy management systems (EMS) for microgrids have improved upon existing methods in several aspects, including prediction of power generated by photovoltaics...
We have previously presented Intent, a medium access control scheme for WLANs based on cooperative, distributed, non-binding frame scheduling. The main idea behind Intent is “intention sharing”—a mechanism that allows a node to be aware of transmissions previously scheduled by its neighbors. We now extend this scheme to networks with hidden nodes. We give a formulation of the scheduling problem and...
With spreading of renewable energy in energy mix of national grids, the issue of high capacity and efficient energy storage is becoming very critical. A comprehensive model of South African power grid developed at the University of Pretoria is presented in this work. The model contains all notable power generators in the country. Mixed integer non-linear optimisation techniques are employed for unit...
The operational optimization of large hydrological basins still remains a challenger issue. Large travel times of the water between upstream reservoirs and the mouth of the river, several days as horizon of optimization, very nonlinear equations, uncertainties and ecological constraints result in complex optimization problems with difficult solutions. The present work uses a new formulation, with...
This paper presents a study on the implementation of Real-Time Pricing (RTP) based Demand Side Management (DSM) of water pumping at a clean water pumping station in Northern Ireland, with the intention of minimising electricity costs and maximising the usage of electricity from wind generation. A Genetic Algorithm (GA) was used to create pumping schedules based on system constraints and electricity...
The increase in renewable energy generators introduced into the electricity grid is putting pressure on its stability and management as predictions of renewable energy sources cannot be accurate or fully controlled. This, with the additional pressure of fluctuations in demand, presents a problem more complex than the current methods of controlling electricity distribution were designed for. A global...
The current flow-based capacity calculation methodology applied in the European electricity market forces the TSOs to re-think their concepts and methodologies for network planning and investment justification. Until now, these methods have been based on methods for de-coupling of TSOs zones, based on cross-border bilateral exchanges, with reduced complexity. The main instrument of de-coupled planning...
In this paper, we present an evolutionary algorithm to place VLSI elements based on evolutionary computing with multi-chromosomes. In addition, we present possible software implementation of the algorithm based on multithread CUDA programming, and report some experimental results of the suggested algorithm implementation.
This paper presents a comparison of two logistic systems including an intermediate platform for the collection and delivery of containers with the maritime container terminals in Le Havre Port area. The first one uses a conventional operational organization of a set of rail shuttles. The second one SFM (‘Service Ferroviaire Modulaire’: modular rail service) is based on the first but with teleoperated...
Mixed-Criticality Systems are capable of accommodatingtasks of varying criticality. In this paper, these are [life, mission, and non-critical]. Tasks usually have an overestimatedexecution time to allow for the Worst Case Execution Time(WCET). When these tasks finish execution prior to their allottedexecution time due to pessimistic assumptions present in the staticanalysis of the system. The surplus...
The Cloud has become a popular choice for many organisations wishing to build an infrastructure for their products. Many new Infrastructure-as-a-Service solutions are becoming available with a growing number of supported pricing models. The recent availability of different pricing schemes, based on resource utilisation and uptime, reveals new challenges in an already complex capacity planing process...
We present an architecture for integrated data centre energy management developed in the EC funded GENiC project. The architecture was devised to create a platform that can integrate functions for workload management, cooling, power management and control of heat recovery for future, highly efficient data centres. The architecture is based on a distributed systems approach that allows the integration...
This paper describes the first use of test structure chips designed to characterise the fundamental properties of Ni and NiFe alloy films deposited using electroplating. This approach is used to perform a chip-level investigation into the effects of electrolyte bath composition on the characteristics of deposited Ni and NiFe layers. The advantage of this methodology is that each electrolyte change...
This paper describe a new technology in the renewable energy field. This technology consists to optimise one of the most important photovoltaic performances. In fact, An optical device will be added to the solar panel in order to improve efficiency. The system was been modelled and simulated. Simulation results confirmed the theoretical assumptions about the efficiency gain reached by our new technology...
In this paper the design of a linear electrical machine for use with a free-piston engine will be discussed. Three conventional permanent magnet machines are compared to a flux switching and modulated pole machine. Each of the topologies is optimised to give a specific force whilst adhering to a limit on the mass of the moving component. Using simple vector analysis, it is shown that machine power...
In the past few years interest in the use of low speed permanent magnet generators for direct-drive wind turbine generator applications has increased significantly. The significant fluctuations in NdFeB magnet prices has encouraged designers to optimise magnet utilisation and to look at alternative magnet materials for wind turbine electrical generators. In this paper an analytical design model is...
This paper forms part of a broader study on the design and optimisation of a high speed switched reluctance motor (SRM) for hybrid-electrical automotive traction applications. The main focus of this particular paper is to explain the design optimisation methodology followed. Furthermore, the main aim of the motor design is to push the power density of the SRM as high as possible. This leads to numerous...
In this paper a performance comparison of permanent magnet (PM) salient rotor topologies is conducted. The analysis has been carried out for a machine design case study where numerous design requirements need to be satisfied simultaneously. The requirements include: low speed, high torque, low-duty transient operation and zero-speed injection based sensorless control capability. The majority of work...
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