There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

http://ieeexplore.ieee.org/iel5/5/31047/01444179.pdf

Fundamentals of acoustics

Smart Energy Systems for coherent 100% renewable energy and transport solutions

Tremendous efforts are being made to develop electrode materials, electrolytes, and separators for energy storage devices to meet the needs of emerging technologies such as electric vehicles, decarbonized electricity, and electrochemical energy storage. However, the sustainability concerns of lithium-ion batteries (LIBs) and next-generation rechargeable batteries have received little attention. Recycling plays an important role in the overall sustainability of future batteries and is affected by battery attributes including environmental hazards and the value of their constituent resources. Therefore, recycling should be considered when developing battery systems. Herein, we provide a systematic overview of rechargeable battery sustainability. With a particular focus on electric vehicles, we analyze the market competitiveness of batteries in terms of economy, environment, and policy. Considering the large volumes of batteries soon to be retired, we comprehensively evaluate battery utilization and recycling from the perspectives of economic feasibility, environmental impact, technology, and safety. Battery sustainability is discussed with respect to life-cycle assessment and analyzed from the perspectives of strategic resources and economic demand. Finally, we propose a 4H strategy for battery recycling with the aims of high efficiency, high economic return, high environmental benefit, and high safety. New challenges and future prospects for battery sustainability are also highlighted.

Sustainable Recycling Technology for Li-Ion Batteries and Beyond: Challenges and Future Prospects.

Although the concept of transportation electrification holds enormous prospects in addressing the global environmental pollution problem, in reality the market penetration of plug-in electric vehicles (PEVs) has been very low. Consumer concerns over the limited availability of charging facilities and unacceptably long charging periods are major factors behind this low penetration rate. From the perspective of the electricity grid, a longer PEV peak load period can potentially overlap with the residential peak load period, making energy management more challenging. A suitably designed charging strategy can help to address these concerns, which motivated us to conduct this research. In this paper, we present a smart charging strategy for a PEV network that offers multiple charging options, including ac level 2 charging, dc fast charging, and battery swapping facilities at charging stations. For a PEV requiring charging facilities, we model the issue of finding the optimal charging station as a multiobjective optimization problem, where the goal is to find a station that ensures the minimum charging time, travel time, and charging cost. We extend the model to a metaheuristic solution in the form of an ant colony optimization. Simulation results show that the proposed solution significantly reduces waiting time and charging cost.

Smart Charging Strategy for Electric Vehicle Charging Stations

Small cell networks (SCNs) are envisaged as a key technology enabling the fifth-generation (5G) wireless communication system to address the challenge of rising mobile data demand. Green communications will be another major attribute of 5G systems, as power consumption from the information and communication technology sector is forecast to increase significantly by 2030. Accordingly, energy-efficient SCN design has attracted significant attention from researchers in recent years. In addition, to enable the ubiquitous deployment of dense small cells, service providers require energy-efficient backhauling solutions. In this paper, we present an energy-efficient communication model for 5G heterogeneous networks (HetNets). The proposed model considers both the access and backhaul network elements. We formulate and present an analytical model to calculate the optimum number of small cells that need to be kept active at various times of the day in order to minimize power consumption while meeting users’ quality of service demands. Based on our critical investigation of backhaul power consumption, we also isolate and present two energy-efficient backhauling solutions for 5G HetNets. Simulated results reveal that the proposed green communication model saves up to 48% more power than other existing models.

A Green Communication Model for 5G Systems

The charging loads of plug-in electric vehicles (PEVs) within a network of charging stations (CSs) are not uniformly distributed. The load distribution is skewed toward the stations located in the hotspot areas, instigating longer queues and waiting times, particularly during afternoon peak traffic hours. This can lead to a major challenge for the utilities in the form of an extended PEV load period, which could overlap with the residential evening peak load hours, increase peak demand, and cause serious issues, such as network instability and power outages. This paper presents a new coordinated dynamic pricing model to reduce the overlaps between residential and CS loads by inspiring the temporal PEV load shifting during evening peak load hours. The new idea is to dynamically adjust the price incentives to drift PEVs toward less popular/underutilized CSs. We formulate a constraint optimization problem and introduce a heuristic solution to minimize the overlap between the PEV and residential peak load periods. Our extensive simulation results indicate that the proposed model significantly reduces the overlap and the PEV load during evening peak hours.

A Coordinated Dynamic Pricing Model for Electric Vehicle Charging Stations

Quantifying economic benefits of second life batteries of gridable vehicles in the smart grid

The IEEE 802.15.4 standard medium access control (MAC) protocol for low rate wireless personal area networks (LRWPAN) is design mainly for static sensor networks and its capability to support mobile sensor networks has not yet been established. To the best knowledge of authors, this is the first paper that evaluates the suitability of IEEE 802.15.4 MAC in mobile sensor networks environment. We evaluate the performance based on node's speed and beacon order, and observe the effect on energy usage, packet delivery ratio and time required to associate with its coordinator. From the experiment we observe that the moving nodes experienced serious problems in association and synchronization and show results on energy usage, throughput , association and reassociation rate with different speeds of moving node. We also identify some key research problems that need to be addressed for successful implementations of IEEE 802.15..4 in mobile sensor networks environment.

/pdf/performance-evaluation-of-ieee-802-15-4-for-mobile-sensor-501n113dym.pdf

Iftekhar Ahmad

Papers

Smart Charging Strategy for Electric Vehicle Charging Stations

A Green Communication Model for 5G Systems

A Coordinated Dynamic Pricing Model for Electric Vehicle Charging Stations

Quantifying economic benefits of second life batteries of gridable vehicles in the smart grid

Performance evaluation of IEEE 802.15.4 for mobile sensor networks