Abstract

The energy consumption in telecommunication networks is expected to grow considerably, especially in core networks. In this chapter, optimization of energy consumption is approached from two directions. In a first study, multilayer traffic engineering (MLTE) is used to assign energy-efficient paths and logical topology to IP traffic. The relation with traditional capacity optimization is explained, and the MLTE strategy is applied for daily traffic variations. A second study considers the core network below the IP layer, giving a detailed power consumption model. Optical bypass is evaluated as a technique to achieve considerable power savings over per-hop optical–electronic–optical regeneration.

Abstract

Electric cars have the disadvantage of a limited range, and drivers may experience a range anxiety. This range anxiety can be solved by adding a range extender. But, the range extender should be light so as not to significantly increase the weight of the original vehicle. In urban areas with dense traffic (usually developing countries), the average speed around cities is typically lower than 50km/h. This means, the rolling resistance losses are more important than aerodynamic losses, and a weight reduction results in a bigger electrical range. Therefore, smaller and lighter range extenders are of much interest. The contribution of this paper is to indicate the possibility of range extenders with less than 25 kg with a capacity of 150 to 200 cc to suit a condition where weight counts. In this paper, the cost, environmental and grid impacts of going electric are also discussed. The effect of high altitude and driving style on the performance of an electric vehicle is assessed. The challenges and opportunities of vehicle electrification between countries with decarbonated power generation and fossil fuel dominated power generation are highlighted. Throughout the article, the case of Ethiopia is taken as an example.

Abstract

For cloud enterprise customers that require services on demand, data centers must allocate and partition data center resources in a dynamic fashion. We consider the problem in which a request from an enterprise customer is mapped to a virtual network (VN) that is allocated requiring both bandwidth and compute resources by connecting it from an entry point of a data center to one or more servers, should this data center be selected from multiple geographically distributed data centers. We present a dynamic traffic engineering framework, for which we develop an optimization model based on a mixed-integer linear programming (MILP) formulation that a data center operator can use at each review point to optimally assign VN customers. Through a series of studies, we then present results on how different VN customers are treated in terms of request acceptance when each VN class has a different resource requirement. We found that a VN class with a low resource requirement has a low blocking even in heavy traffic, while the VN class with a high resource requirement faces a high service denial. On the other hand, cost for the VN with the highest resource requirement is not always the highest in the heavy traffic because of the significantly high service denial faced by this VN class.

Abstract

In 2010 the MOVE project started in the collection and analysis of crowd behaviour data. The two main goals of the project are first, the collection of data through the use of mobile phones. The second goal is to develop new technologies to process and mine the collected data for crowd behaviour analysis. The technology will allow to make advanced interpretations of historic and dynamic mobile crowd data coming from GSM/GPS and from different classes of users (vehicle, pedestrian, indoor/outdoor). Fusion will be made between data coming from different sources (smartphone, navigation device) and external map data. The interpretation will allow the mining of advanced features/geometry from the crowd data as well as the dynamic (travel) behavior of the population.

Abstract

A strain-based flaw assessment procedure is recommended for girth welded pipelines subjected to large deformations. To evaluate the allowable defect dimensions, the tearing resistance needs to be characterized. This paper investigates the effect of weld metal strength mismatch on the resistance curve using Single Edge Notched Tension (SENT) specimens. Several advanced measurement techniques are applied during the tests in order to obtain a continuous measurement of crack extension and to visualize the deformation fields near the crack. The resistance curves are determined using a single specimen technique. The unloading compliance method and the potential drop method result in similar predictions of ductile crack extension, yielding similar resistance curves. Next to these measurements, the full field deformations are determined using digital image correlation. The experiments indicate that the position of the applied notch in the weld has the potential to influence the strain fields.

Abstract

This paper introduces advanced power-electronic converter topologies for Electric Vehicles (EVs) using a four-phase DC/DC interleaved boost converter (FP-IBC) and a five-level T-type DC/AC multilevel converter. A comparison between the proposed topologies and other converter topologies is performed and discussed. The simulation results are analysed to evaluate the converters based on power loss calculations and harmonic analysis. The converters are studied at different switching frequencies and various loading conditions to reflect their effects on the converter losses. The results highlight the proposed converters' higher efficiency compared to other studied converter topologies in electric vehicle applications.

Abstract

The constantly decreasing prices of the battery storage systems make them a very attractive solution for mitigating over voltages and voltage unbalance in low voltage grids with high penetration of renewable energy resources. A centralised storage device, connected at the end of the feeder can be a very effective solution for dealing with over voltages. The classical positive-sequence control strategy is usually employed in these devices to ensure a power exchange between the grid and the battery and vice versa. Nevertheless, the voltage unbalance cannot be mitigated by the classical control strategies. In this article, a modified three-phase damping control strategy is used to discharge and charge the battery storage system. This control strategy has an improved resistive behavior towards the zero- and negative-sequence components which mitigates the voltage unbalance by injecting or drawing asymmetrical phase currents. Thus both power quality problems are mitigated.

Abstract

In this article a three-phase BLDC motor controller for use in an Ultra-Light Electrical Vehicle is presented. The control is performed using a Programmable Logic Device (CPLD), which doesn’t require any additional processor. In this way a robust and low-complexity control is obtained. For extending the speed range of the BLDC, a phase advance circuit is implemented as well. The power consumption of the controller is very low which is an interesting feature in battery applications.