Economic benefit of the National Broadband Network

This paper argues that all regions benefit from the NBN but the economic effects are greater in the major cities because of their larger economic activity. Executive summary This paper is a partial summary of a study undertaken in the Centre for Energy-Efficient Telecommunications (CEET) at the University of Melbourne. The study focuses on the potential economic impact of Australia’s NBN. The NBN affects the economy by making online services more widely available. Taking a conservative approach, we have considered just six categories of online services (cloud computing, electronic commerce, online higher education, telehealth practice, teleworking, and entertainment) from which there are documented economic benefits. We have attributed to the NBN only the additional benefit derived from its deployment over and above what we estimate would have been the broadband situation in Australia without the NBN. That is, we have not assumed that broadband availability would have stagnated without the NBN. We do expect, however, that future services will require higher access speeds, generally in the range 10-25 Mb/s. With this assumption and using a well-attested model of the Australian economy, we show that, in the long term, real GDP can be boosted by about 1.8% and real household consumption (a measure of national welfare) by about 2.0%. When we take into account the need to repay the cost of the NBN, GDP increases slightly but the benefit to real household consumption is reduced to 1.4%. Most of the benefit comes from telehealth and teleworking. Because the access speeds (downstream and upstream) required for the services are quite uncertain, we have looked at the effects of access speeds. If all the services except entertainment can be provided with no more than 2.5 Mb/s down and up (typical of implementations today), then the costs of the NBN outweigh the benefits. Real GDP increases by less than 0.2% but real household consumption declines by 0.4%. That is, building an NBN just for entertainment is not economically viable. An analysis of the regional distribution of benefits shows that all regions benefit from the NBN but the economic effects are greater in the major cities because of their larger economic activity

Measured unsteady transonic aerodynamic characteristics of an elastic supercritical wing with an oscillating control surface

Transonic steady and unsteady aerodynamic data were measured on a large elastic wing in the NASA Langley Transonic Dynamics Tunnel. The wing had a supercritical airfoil shape and a leading-edge sweepback of 28.8 deg. The wing was heavily instrumented to measure both static and dynamic pressures and deflections. A hydraulically driven outboard control surface was oscillated to generate unsteady airloads on the wing. Representative results from the wind tunnel tests are presented and discussed, and the unexpected occurrence of an unusual dynamic wing instability, which was sensitive to angle of attack, is reported

Exploring the role of messenger effects and feedback frames in promoting uptake of energy-efficient technologies

The persuasive potential for varying messenger types and feedback frames to increase pro-environmental choice was explored in a 2 (feedback frame: financial vs. environmental) × 5 (messenger type: neighbour, government, industry, utilities vs. control) factorial design experiment. Using the context of home heating choice, 493 non-student participants were given information on either the financial or environmental benefits of selecting an energy-efficient heat pump versus a standard boiler, as described by one of four messenger types (versus a no-messenger control). Likelihood of selecting the ‘green’ technology was assessed, as well as any carry-over effects on real-life behavioural intentions. Additionally, we assessed the messenger attributes that appeared to be most important in this context, in terms of whether sources that were perceived to be trustworthy, knowledgeable, or a combination of both dimensions, would hold greater sway over preference formation. Overall, no evidence was found for any impact of messenger type on either preference formation or behavioural intentions. However, message content (i.e. how information on the benefits of pro-environmental choice was framed), was found to have substantial impact on behaviour; with the financial versus environmental decision frame being significantly more likely to encourage uptake of the energy-efficient versus standard technology. We suggest that the level of processing required for the kinds of large-scale purchase decisions we consider here may explain the lack of any messenger effect on choice behaviour. Implications for the development of behaviour change interventions designed to promote consideration of energy-efficient technologies in this context are discussed

Energy-efficient motors

The use of a copper-squirrel cage in induction motors has been analyzed testing a prototype rated 1.1 kW and comparing the performances with a twin machine with an aluminum cage. The comparison has been made using torque, efficiency, starting torque, and starting current. For the considered machine size, the obtained results show that the simple substitution of the aluminum with copper can improve the efficiency of no more than 1.5% at rated load. Taking into account the copper market cost trend, the use of copper cage increases the break-even time due to the higher cost of copper rotor respect to the aluminum one. For this reason, the discussion about the use of copper cage can be still considered ope

Energy-Efficient Algorithms

We initiate the systematic study of the energy complexity of algorithms (in addition to time and space complexity) based on Landauer's Principle in physics, which gives a lower bound on the amount of energy a system must dissipate if it destroys information. We propose energy-aware variations of three standard models of computation: circuit RAM, word RAM, and transdichotomous RAM. On top of these models, we build familiar high-level primitives such as control logic, memory allocation, and garbage collection with zero energy complexity and only constant-factor overheads in space and time complexity, enabling simple expression of energy-efficient algorithms. We analyze several classic algorithms in our models and develop low-energy variations: comparison sort, insertion sort, counting sort, breadth-first search, Bellman-Ford, Floyd-Warshall, matrix all-pairs shortest paths, AVL trees, binary heaps, and dynamic arrays. We explore the time/space/energy trade-off and develop several general techniques for analyzing algorithms and reducing their energy complexity. These results lay a theoretical foundation for a new field of semi-reversible computing and provide a new framework for the investigation of algorithms.Comment: 40 pages, 8 pdf figures, full version of work published in ITCS 201

Energy-Efficient Design for Downlink Cloud Radio Access Networks

This work aims to maximize the energy efficiency of a downlink cloud radio access network (C-RAN), where data is transferred from a baseband unit in the core network to several remote radio heads via a set of edge routers over capacity-limited fronthaul links. The remote radio heads then send the received signals to their users via radio access links. We formulate a new mixed-integer nonlinear problem in which the ratio of network throughput and total power consumption is maximized. This challenging problem formulation includes practical constraints on routing, predefined minimum data rates, fronthaul capacity and maximum RRH transmit power. By employing the successive convex quadratic programming framework, an iterative algorithm is proposed with guaranteed convergence to a Fritz John solution of the formulated problem. Significantly, each iteration of the proposed algorithm solves only one simple convex program. Numerical examples with practical parameters confirm that the proposed joint optimization design markedly improves the C-RAN's energy efficiency compared to benchmark schemes.This work is supported in part by an ECR-HDR scholarship from The University of Newcastle, in part by the Australian Research Council Discovery Project grants DP170100939 and DP160101537, in part by Vietnam National Foundation for Science and Technology Development under grant number 101.02-2016.11 and in part by a startup fund from San Diego State University

Energy-efficient control of pump units based on neural-network parameter observer

An observer based on an artificial neural network was designed. The observer determines the pumping unit performance depending on the operating point. Determination is based on the measured technological coordinates of the system and the pressure of the turbomechanism. Three neural networks were designed for three types of the productivity observer. The developed observer was investigated by the simulation method within different variations of disturbing actions, such as hydraulic resistance of the hydraulic system and geodetic pressure. A comparative analysis of three types of the productivity observer, built with using the pressure and different signals of the system with arbitrary change of hydraulic resistance was given. By the use of the pump unit efficiency observer, in addition to the results presented earlier, the efficiency of the productivity observer, which built with using different sensors, in water supply systems with two series-connected pump units, operating for filling the large tank, is researched. In the water supply system one pump speed is regulated, the other is unregulated. References 14, figures 5

Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters

Energy-efficient task allocation for distributed applications in Wireless Sensor Networks

We consider the scenario of a sensing, computing and communicating infrastructure with a a programmable middleware that allows for quickly deploying different applications running on top of it so as to follow the changing ambient needs. We then face the problem of setting up the desired application in case of hundreds of nodes, which consists in identifying which actions should be performed by each of the nodes so as to satisfy the ambient needs while minimizing the application impact on the infrastructure battery lifetime. We approach the problem by considering every possible decomposition of the application's sensing and computing operations into tasks to be assigned to the each infrastructure component. The contribution of energy consumption due to the performance of each task is then considered to compute a cost function, allowing us to evaluate the viability of each deployment solution. Simulation results show that our framework results in considerable energy conservation with respect to sink-oriented or cluster-oriented deployment approaches, particularly for networks with high node densities, non-uniform energy consumption and initial energy, and complex actions

Energy-efficient traffic engineering

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 opticalelectronicoptical regeneration. Document type: Part of book or chapter of boo