79,985 research outputs found
Decentralized energy efficient model for data transmission in IoT-based healthcare system
The growing world population is facing challenges such as increased chronic diseases and medical expenses. Integrate the latest modern technology into healthcare system can diminish these issues. Internet of medical things (IoMT) is the vision to provide the better healthcare system. The IoMT comprises of different sensor nodes connected together. The IoMT system incorporated with medical devices (sensors) for given the healthcare facilities to the patient and physician can have capability to monitor the patients very efficiently. The main challenge for IoMT is the energy consumption, battery charge consumption and limited battery lifetime in sensor based medical devices. During charging the charges that are stored in battery and these charges are not fully utilized due to nonlinearity of discharging process. The short time period needed to restore these unused charges is referred as recovery effect. An algorithm exploiting recovery effect to extend the battery lifetime that leads to low consumption of energy. This paper provides the proposed adaptive Energy efficient (EEA) algorithm that adopts this effect for enhancing energy efficiency, battery lifetime and throughput. The results have been simulated on MATLAB by considering the Li-ion battery. The proposed adaptive Energy efficient (EEA) algorithm is also compared with other state of the art existing method named, BRLE. The Proposed algorithm increased the lifetime of battery, energy consumption and provides the improved performance as compared to BRLE algorithm. It consumes low energy and supports continuous connectivity of devices without any loss/interruptions
Battery Modeling
The use of mobile devices is often limited by the capacity of the employed batteries. The battery lifetime determines how long one can use a device. Battery modeling can help to predict, and possibly extend this lifetime. Many different battery models have been developed over the years. However, with these models one can only compute lifetimes for specific discharge profiles, and not for workloads in general. In this paper, we give an overview of the different battery models that are available, and evaluate these models in their suitability to combine them with a workload model to create a more powerful battery model. \u
On the Effects of Battery Imperfections in an Energy Harvesting Device
Energy Harvesting allows the devices in a Wireless Sensor Network to recharge
their batteries through environmental energy sources. While in the literature
the main focus is on devices with ideal batteries, in reality several
inefficiencies have to be considered to correctly design the operating regimes
of an Energy Harvesting Device (EHD). In this work we describe how the
throughput optimization problem changes under \emph{real battery} constraints
in an EHD. In particular, we consider imperfect knowledge of the state of
charge of the battery and storage inefficiencies, \emph{i.e.}, part of the
harvested energy is wasted in the battery recharging process. We formulate the
problem as a Markov Decision Process, basing our model on some realistic
observations about transmission, consumption and harvesting power. We find the
performance upper bound with a real battery and numerically discuss the novelty
introduced by the real battery effects. We show that using the \emph{old}
policies obtained without considering the real battery effects is strongly
sub-optimal and may even result in zero throughput.Comment: In Proc. IEEE International Conference on Computing, Networking and
Communications, pp. 942-948, Feb. 201
Least costly energy management for series hybrid electric vehicles
Energy management of plug-in Hybrid Electric Vehicles (HEVs) has different
challenges from non-plug-in HEVs, due to bigger batteries and grid recharging.
Instead of tackling it to pursue energetic efficiency, an approach minimizing
the driving cost incurred by the user - the combined costs of fuel, grid energy
and battery degradation - is here proposed. A real-time approximation of the
resulting optimal policy is then provided, as well as some analytic insight
into its dependence on the system parameters. The advantages of the proposed
formulation and the effectiveness of the real-time strategy are shown by means
of a thorough simulation campaign
Using Battery Storage for Peak Shaving and Frequency Regulation: Joint Optimization for Superlinear Gains
We consider using a battery storage system simultaneously for peak shaving
and frequency regulation through a joint optimization framework which captures
battery degradation, operational constraints and uncertainties in customer load
and regulation signals. Under this framework, using real data we show the
electricity bill of users can be reduced by up to 15\%. Furthermore, we
demonstrate that the saving from joint optimization is often larger than the
sum of the optimal savings when the battery is used for the two individual
applications. A simple threshold real-time algorithm is proposed and achieves
this super-linear gain. Compared to prior works that focused on using battery
storage systems for single applications, our results suggest that batteries can
achieve much larger economic benefits than previously thought if they jointly
provide multiple services.Comment: To Appear in IEEE Transaction on Power System
Fuel Economy of Plug-In Hybrid Electric and Hybrid Electric Vehicles: Effects of Vehicle Weight, Hybridization Ratio and Ambient Temperature
Hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) are evolving rapidly since the introduction of Toyota Prius into the market in 1997. As the world needs more fuel-efficient vehicles to mitigate climate change, the role of HEVs and PHEVs are becoming ever more important. While fuel economies of HEVs and PHEVs are superior to those of internal combustion engine (ICE) powered vehicles, they are partially powered by batteries and therefore they resemble characteristics of battery electric vehicles (BEVs) such as dependence of fuel economy on ambient temperatures. It is also important to understand how different extent of hybridization (a.k.a., hybridization ratio) affects fuel economy under various driving conditions. In addition, it is of interest to understand how HEVs and PHEVs compare with BEVs at a similar vehicle weight. This study investigated the relationship between vehicle mass and vehicle performance parameters, mainly fuel economy and driving range of PHEVs focused on 2018 and 2019 model years using the test data available from fuel economy website of the US Environmental Protection Agency (EPA). Previous studies relied on modeling to understand mass impact on fuel economy for HEV as there were not enough number of HEVs in the market to draw a trendline at the time. The study also investigated the effect of ambient temperature for HEVs and PHEVs and kinetic energy recovery of the regenerative braking using the vehicle testing data for model year 2013 and 2015 from Idaho National Lab (INL). The current study assesses current state-of-art for PHEVs. It also provides analysis of experimental results for validation of vehicle dynamic and other models for PHEVs and HEVs
Algorithms for balancing demand-side load and micro-generation in Islanded Operation
Micro-generators are devices installed in houses pro-\ud
ducing electricity at kilowatt level. These appliances can\ud
increase energy efficiency significantly, especially when\ud
their runtime is optimized. During power outages micro-\ud
generators can supply critical systems and decrease dis-\ud
comfort.\ud
In this paper a model of the domestic electricity infras-\ud
tructure of a house is derived and first versions of algo-\ud
rithms for load/generation balancing during a power cut\ud
are developed. In this context a microCHP device, produc-\ud
ing heat and electricity at the same time with a high effi-\ud
ciency, is used as micro-generator.\ud
The model and the algorithms are incorporated in a sim-\ud
ulator, which is used to study the effect of the algorithms for\ud
load/generation balancing. The results show that with some\ud
extra hardware all appliances in a house can be supplied,\ud
however not always at the preferred time.\u
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