Metamaterials are artificial media structured on a size scale smaller than wavelength of external stimuli, and they can exhibit a strong localization and enhancement of fields, which may provide novel tools to significantly enhance the sensitivity and resolution of sensors, and open new degrees of freedom in sensing design aspect. This paper mainly presents the recent progress concerning metamaterials-based sensing, and detailedly reviews the principle, detecting process and sensitivity of three distinct types of sensors based on metamaterials, as well as their challenges and prospects. Moreover, the design guidelines for each sensor and its performance are compared and summarized.

https://www.mdpi.com/1424-8220/12/3/2742/pdf

Metamaterials application in sensing.

The black start capability is vital for microgrids, which can potentially improve the reliability of the power grid. This paper proposes a black start strategy for microgrids based on a parallel restoration strategy. Considering the characteristics of distributed generations (DGs), an evaluation model, which is used to assess the black start capability of DGs, is established by adopting the variation coefficient method. Thus, the DGs with good black start capability, which are selected by a diversity sequence method, are restored first in parallel under the constraints of DGs and network. During the selection process of recovery paths, line weight and node importance degree are proposed under the consideration of the node topological importance and the load importance as well as the backbone network restoration time. Therefore, the whole optimization of the reconstructed network is realized. Finally, the simulation results verify the feasibility and effectiveness of the strategy.

A Parallel Restoration for Black Start of Microgrids Considering Characteristics of Distributed Generations

Split-ring resonators (SRRs) are ideal structures for the realization of compact high-sensitivity and high-resolution sensors due to their high-quality factor resonance, compact size, and high sensitivity to changes in the constituent materials and physical dimensions. This paper presents a displacement sensor based on a diamond-shaped tapered SRR coupled to a coplanar waveguide. Two significant improvements over previous designs are reported. Firstly, the proposed sensor has higher dynamic range and linearity for displacement sensing. Secondly, compared with previous designs, where the displacement changes both the resonant frequency and depth of the transmission notch, the proposed sensor has a fixed resonant frequency. This is an important improvement since the sensor can be operated at a single fixed frequency and bypass the need for a frequency-sweeping microwave source and measurement system such as an expensive network analyzer. It is shown that, while preserving the compact size, the proposed sensor also benefits from a lower operating frequency. The design principle and simulation results are validated through measurement.

/pdf/displacement-sensor-based-on-diamond-shaped-tapered-split-2mtjh4e5lb.pdf

Displacement Sensor Based on Diamond-Shaped Tapered Split Ring Resonator

Survey of multi-agent systems for microgrid control

In the past two decades, the development and steady improvement of terahertz technology has motivated a wide range of scientific studies designed to discover and develop terahertz applications. Terahertz sensing is one such application, and its continued maturation is virtually guaranteed by the unique properties that materials exhibit in the terahertz frequency range. Thin-film sensing is one branch of this effort that has enjoyed diverse development in the last decade. Deeply subwavelength sample thicknesses impose great difficulties to conventional terahertz spectroscopy, yet sensing those samples is essential for a large number of applications. In this article we review terahertz thin-film sensing, summarizing the motivation, challenges, and state-of-the-art approaches based predominately on terahertz time-domain spectroscopy.

A Review on Thin-film Sensing with Terahertz Waves

Microgrids have become a hot topic driven by the dual pressures of environmental protection concerns and the energy crisis. In this paper, a challenge for the distributed control of a modern electric grid incorporating clusters of residential microgrids is elaborated and a hierarchical multi-agent system (MAS) is proposed as a solution. The issues of how to realize the hierarchical MAS and how to improve coordination and control strategies are discussed. Based on MATLAB and ZEUS platforms, bilateral switching between grid-connected mode and island mode is performed under control of the proposed MAS to enhance and support its effectiveness.

/pdf/hierarchical-mas-based-control-strategy-for-microgrid-29wutsvyhm.pdf

Hierarchical MAS Based Control Strategy for Microgrid

A novel Ω-shaped double negative (DNG) material-assisted microwave sensor is presented, and modelled using a full wave electromagnetic commercial simulator CST. Simulating results show that the amplified evanescent wave is sensitive to the permittivity of dielectric material in the detecting zone. Meanwhile, mechanism of the evanescent wave amplification is explained. Comparing with conventional microwave resonant sensor, the Ω-shaped DNG materials-assisted microwave sensor allows for much higher sensitivity.

Modelling and Analysis of Ω-shaped Double Negative Material-assisted Microwave Sensor

Nowadays wireless communication has become ubiquitous around the world and its application for gauging consumption of utilities by customers is rapidly gaining pace, not only in the developed world but also in the developing countries In this paper, we propose a automatic meter reading (AMR) system which is a combination of wireless sensor network (WSN) and worldwide interoperability for microwave access (WiMAX) technology, and its feasibility and effectiveness are verified by the experiment in Yuxi city, Yunnan province, China Results show that both A-C and A-B-D communication links have excellent link quality, and the success rates of meter reading are about 100% The packet loss rates were close to zero, and the average delays were 32ms and 33ms, respectively, while 1000 packets were sent

A pilot AMR system based on WIMAX and WSN

Connectivity and coverage problem is an important and fundamental issue in sensor networks, which reflects how well a sensor network is communication-connected and monitored by sensors. While connectivity and coverage problem in two dimensional wireless sensor networks (WSNs) have been well studied, three dimensional WSNs have gained relatively less attention in present literatures. This paper discusses the connectivity and coverage problem in random deployed three dimensional WSNs. We propose an experimental analysis of the fundamental relationship between connectivity probability, the number of nodes and the nodes' transmitting ranges. Based on probability model, we calculate a feasible range of the number of nodes for an effective sensing coverage in a three dimensional sensing field. Thus, a practical guidance for random deployment in three dimensional WSNs from connectivity and coverage perspective is given.

Full connectivity and probabilistic coverage in random deployed 3D WSNs

Sensor networks are especially useful in catastrophic or disaster scenarios such as abysmal sea, floods, fires, or earthquakes where human participation may be too dangerous. Storage technologies take a critical position for WSNs in such scenarios since the sensor nodes may themselves fail unpredictably, resulting in the loss of valuable data. This paper focuses on fountain code-based data storage and recovery solutions for WSNs in disaster scenarios. A review on current technologies is given on challenges posed by disaster environments. Two information fusion-based distributed storage (IFDS) algorithms are proposed in the “few global knowledge” and “zero-configuration” paradigm, respectively. Correspondingly, a high-efficient retrieve algorithm is designed for general storage algorithms using Robust Soliton distribution. We observe that the successful decoding probability can be provisioned by properly selecting parameters—the ratio of number of source node and total nodes, and the storage capacity M in each node.

/pdf/information-fusion-based-storage-and-retrieve-algorithms-for-2xvt3xgpzq.pdf

Jihong Shi

Papers

Hierarchical MAS Based Control Strategy for Microgrid

Modelling and Analysis of Ω-shaped Double Negative Material-assisted Microwave Sensor

A pilot AMR system based on WIMAX and WSN

Full connectivity and probabilistic coverage in random deployed 3D WSNs

Information Fusion-Based Storage and Retrieve Algorithms for WSNs in Disaster Scenarios