- Wireless Systems Applied to e-Health: Radio-Planning, Energy Efficiency, and System Integration

2015 ◽  
pp. 246-281
2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Ngoc Phuc Le ◽  
Le Chung Tran ◽  
Farzad Safaei

The use of per-subcarrier antenna subset selection in OFDM wireless systems offers higher system capacity and/or improved link reliability. However, the implementation of the conventional per-subcarrier selection scheme may result in significant fluctuations of the average power and peak power across antennas, which affects the potential benefits of the system. In this paper, power efficiency of high-power amplifiers and energy efficiency in per-subcarrier antenna selection MIMO-OFDM systems are investigated. To deliver the maximum overall power efficiency, we propose a two-step strategy for data-subcarrier allocation. This strategy consists of an equal allocation of data subcarriers based on linear optimization and peak-power reduction via cross-antenna permutations. For analysis, we derive the CCDF (complementary cumulative distribution function) of the power efficiency as well as the analytical expressions of the average power efficiency. It is proved from the power-efficiency perspective that the proposed allocation scheme outperforms the conventional scheme. We also show that the improvement in the power efficiency translates into an improved capacity and, in turn, increases energy efficiency of the proposed system. Simulation results are provided to validate our analyses.


Author(s):  
Yang Zhang ◽  
Jie Tang ◽  
Lihua Pang ◽  
Yunhui Guo ◽  
Yijian Chen ◽  
...  

Author(s):  
Chaoyang Zhang ◽  
Pingyu Jiang ◽  
Lei Zhang ◽  
Peihua Gu

Increasing energy consumption of manufacturing industry demands novel approaches to achieve energy conservation and emission reduction. Most of the previous research efforts in this area focused more on analyzing manufacturing energy consumption of a process or that of a machine tool with less concern on the system level of advanced machining workshop, especially a flexible manufacturing system. In this article, a new energy-saving approach of flexible manufacturing system is put forward based on energy evaluation model for integration of process planning and scheduling problem in flexible manufacturing system (flexible manufacturing system-integration of process planning and scheduling). First, complying with feature precedence and other technological requirements, flexible manufacturing system -integration of process planning and scheduling is mapped as an asymmetric traveling salesman problem of which operations are provinces and candidate operations are cities belonging to different provinces. To evaluate the performance of each solution of the asymmetric traveling salesman problem, energy consumption evaluation criteria for flexible manufacturing system-integration of process planning and scheduling are established and three energy efficiency indicators are also provided to perform further analysis on manufacturing energy consumption, that is, part energy efficiency, machine tool energy efficiency and feasible solution energy efficiency. Then, a mutation-combined ant colony optimization algorithm is proposed to solve the flexible manufacturing system-integration of process planning and scheduling which combined roulette and mutation selection methods to pick out the next candidate operation. The pheromone trails associated with edges are released by the so-far-best ant or the iteration-best ant probabilistically to both keep the search directed and avoid converging to the local best. Finally, a case study of flexible manufacturing system in advanced machining workshop is employed to demonstrate the feasibility and applicability of this approach in three different scenarios and compared with the “process planning then scheduling” approach; energy consumption obtained by the proposed method drops 10.7%.


2019 ◽  
Vol 136 ◽  
pp. 01027
Author(s):  
Xiaodong Cao ◽  
Shihai Yang ◽  
Feng Ji ◽  
Songyang Liu ◽  
Xu Zhou

The high permeability of household distributed photovoltaic is prevalent after its access. The connection between distributed generation and main network is cut off quickly and the energy storage device is used to realize energy storage. From the point of view of economy and rationality, the above-mentioned operation has become increasingly unable to meet the health of the grid after the access of distributed generation. In this paper, a construction scheme and operation strategy of household micro-grid including household energy efficiency management is designed by using equipment and equipment integration, equipment and system integration, system and system integration of household micro-grid and household energy efficiency management. It adds in-situ absorption capacity of distributed photovoltaic, realizes efficient integration of household energy efficiency management and household microgrid, effectively solves the problems of high permeability of household distributed generation, and has certain application value in the user side.


2019 ◽  
Vol 13 (1) ◽  
pp. 129-144 ◽  
Author(s):  
Carolina Koronen ◽  
Max Åhman ◽  
Lars J Nilsson

AbstractEnd-use efficiency, demand response and coupling of different energy vectors are important aspects of future renewable energy systems. Growth in the number of data centres is leading to an increase in electricity demand and the emergence of a new electricity-intensive industry. Studies on data centres and energy use have so far focused mainly on energy efficiency. This paper contributes with an assessment of the potential for energy system integration of data centres via demand response and waste heat utilization, and with a review of EU policies relevant to this. Waste heat utilization is mainly an option for data centres that are close to district heating systems. Flexible electricity demand can be achieved through temporal and spatial scheduling of data centre operations. This could provide more than 10 GW of demand response in the European electricity system in 2030. Most data centres also have auxiliary power systems employing batteries and stand-by diesel generators, which could potentially be used in power system balancing. These potentials have received little attention so far and have not yet been considered in policies concerning energy or data centres. Policies are needed to capture the potential societal benefits of energy system integration of data centres. In the EU, such policies are in their nascent phase and mainly focused on energy efficiency through the voluntary Code of Conduct and criteria under the EU Ecodesign Directive. Some research and development in the field of energy efficiency and integration is also supported through the EU Horizon 2020 programme. Our analysis shows that there is considerable potential for demand response and energy system integration. This motivates greater efforts in developing future policies, policy coordination, and changes in regulation, taxation and electricity market design.


Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 831 ◽  
Author(s):  
Neosha Navaei ◽  
Ali Roshanghias ◽  
Martin Lenzhofer ◽  
Michael Ortner

The planar fluxgate is an emerging technology feasible for system integration contrary to it’s bulky 3D counterpart. Recently, a novel structure based on an asymmetric double core layout for improved sensitivity and energy efficiency was proposed. The aim of this paper is, for the first time, to conduct a direct experimental comparison between single- and asymmetric double-core structures. The results confirm the original conjecture and show that asymmetric double core structures can easily boost the sensitivity by a factor of two for similar power supply.


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