Abstract

Windows whose transmittance can be modified by an applied voltage have previously been fabricated from soft, transparent elastomers sandwiched between ITO coated glass and a compliant, silver nanowire top electrode.1 In this contribution we extend the capabilities of the tunable window so that the optical transmittance can be varied spatially over the window according to voltage signals applied to different segments of the back electrode of the window, defined by patterning of individually addressable electrodes. The actuation signals are controlled using TTL-level input signals applied to high voltage switches. We also show that the spatially tunable window can be fabricated on a flexible substrate, such as PET, and the optical transmittance is not affected by bending of the substrate. The use of a polymer substrate not only increases possible applications of this class of voltage controlled light modulation device but also has the potential of reducing cost at an industrial scale by replacing more costly ITO coated glass substrate.

Abstract

We present detailed shape-based analyses to compare the performance of metal foil-based capacitive pressure sensors based on the shape of the diaphragm (top electrode). We perform a detailed analysis on the use of new material and deflection in various shaped diaphragms to act as a performance indicator for pressure-based capacitive sensors. A low-cost, recyclable, and readily available material is used to present an alternative to the expensive materials used in conventional pressure sensors. Diaphragms of five different shapes (circle, ellipse, pentagon, square, and rectangle) are fabricated and analyzed. Mathematical, FEM, and experimental tests are performed for capacitive sensors fabricated in five different shapes. The mathematically calculated deflection for each shaped diaphragm is compared with the results of the corresponding FEM simulations. Two different experiments are performed to verify …

Abstract

Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

Abstract

A sensor system includes at least one sensor configured to detect at least one environmental parameter, a processor coupled to the at least one sensor, and a dissolvable polymer encasing the sensor system.

Abstract

Cantilevers are one of the most utilized mechanical elements for acoustic sensing. In comparison to the edge clamped diaphragms of different shapes, a single edge clamped cantilever makes an acoustic sensor mechanically sensitive for detection of lower pressure. The aspect ratio of cantilevers is one of the most important parameters which affect sensitivity. Herein, we present a mathematical, finite element method and experimental analysis to determine the effect of the aspect ratio on the resonant frequency, response time, mechanical sensitivity, and capacitive sensitivity of a cantilever-based acoustic pressure sensor. Three cantilevers of different aspect ratios (0.67, 1, and 1.5) have been chosen for sound pressure application to detect capacitance change. The cantilever with the smallest aspect ratio (0.67) has the highest response time (206 ms), mechanical sensitivity, and capacitive sensitivity (22 fF), which …

Abstract

Capacitive pressure sensors have several advantages in areas such as robotics, automation, aerospace, biomedical and consumer electronics. We present mathematical modelling, finite element analysis (FEA), fabrication and experimental characterization of ultra-low cost and paper-based, touch-mode, flexible capacitive pressure sensor element using Do-It-Yourself (DIY) technology. The pressure sensing element is utilized to design large-area electronics skin for low-cost prosthetic hands. The presented sensor is characterized in normal, transition, touch and saturation modes. The sensor has higher sensitivity and linearity in touch mode operation from 10 to 40 kPa of applied pressure compared to the normal (0 to 8 kPa), transition (8 to 10 kPa) and saturation mode (after 40 kPa) with response time of 15.85 ms. Advantages of the presented sensor are higher sensitivity, linear response, less diaphragm area …

Abstract

User access control is a crucial requirement in any Internet of Things (IoT) deployment, as it allows one to provide authorization, authentication, and revocation of a registered legitimate user to access real-time information and/or service directly from the IoT devices. To complement the existing literature, we design a new three-factor certificateless-signcryption-based user access control for the IoT environment (CSUAC-IoT). Specifically, in our scheme, a user U's password, personal biometrics, and mobile device are used as the three authentication factors. By executing the login and access control phase of CSUAC-IoT, a registered user (U) and a designated smart device (Si) can authorize and authenticate mutually via the trusted gateway node (GN) in a particular cell of the IoT environment. In our setting, the environment is partitioned into disjoint cells, and each cell will contain a certain number of IoT devices along with a GN. With the established session key between U and Si, both entities can then communicate securely. In addition, CSUAC-IoT supports new IoT devices deployment, user revocation, and password/biometric update functionality features. We prove the security of CSUAC-IoT under the real-or-random (ROR) model, and demonstrate that it can resist several common attacks found in a typical IoT environment using the AVISPA tool. A comparative analysis also reveals that CSUAC-IoT achieves better tradeoff for security and functionality, and computational and communication costs, in comparison to five other competing approaches.

Abstract

In recent years, the Internet of Drones (IoD) has emerged as an important research topic in the academy and industry because it has several potential applications ranging from the civilian to military. In IoD environment, several drones, called Unmanned Aerial Vehicles (UAVs), are deployed in different flying zones that communicate each other to exchange crucial information, and then the information are collected by the Ground Station Server . All the drones and the are registered with a central trusted authority, Control Room prior to their deployment. Since the drones and the communicate over open channel (e.g., wireless medium), there are security and privacy issues in the IoD environment. To handle such issues, in this paper we introduce a blockchain-based access control scheme in the IoD environment that allows secure communication among the drones, and also among the drones and the . Secure data gathered by the form transactions, and those transactions are made into the blocks. The blocks are finally added in the blockchain by the cloud servers connected with the via the Ripple Protocol Consensus Algorithm (RPCA) in a peer-to-peer cloud server network. Once the blocks are added into the blockchain, the transactions containing in the blocks cannot be altered, modified or even removed. We provide all sorts of security analysis including formal security under the random oracle model, informal security and simulation-based formal security verification to assure that the proposed scheme can resist various potential attacks with high probability needed in an IoD environment. In addition, a meticulous comparative analysis among the proposed scheme and other closely related existing schemes shows that our scheme offers more functionality attributes and better security, and also low communication and computation costs as compared to other schemes.

Abstract

In recent years, the Internet of Things (IoT) has exploded in popularity. The smart home, as an important facet of IoT, has gained its focus for smart intelligent systems. As users communicate with smart devices over an insecure communication medium, the sensitive information exchanged among them becomes vulnerable to an adversary. Thus, there is a great thrust in developing an anonymous authentication scheme to provide secure communication for smart home environments. Most recently, an anonymous authentication scheme for smart home environments with provable security has been proposed in the literature. In this paper, we analyze the recent scheme to highlight its several vulnerabilities. We then address the security drawbacks and present a more secure and robust authentication scheme that overcomes the drawbacks found in the analyzed scheme, while incorporating its advantages too. Finally, through a detailed comparative study, we demonstrate that the proposed scheme provides significantly better security and more functionality features with comparable communication and computational overheads with similar schemes.

Abstract

The sinkhole attack in an edge-based Internet of Things (IoT) environment (EIoT) can devastate and ruin the whole functioning of the communication. The sinkhole attacker nodes (SHAs) have some properties (for example, they first attract the other normal nodes for the shortest path to the destination and when normal nodes initiate the process of sending their packets through that path (i.e., via SHA), the attacker nodes start disrupting the traffic flow of the network). In the presence of SHAs, the destination (for example, sink node i.e., gateway/base station) does not receive the required information or it may receive partial or modified information. This results in reduction of the network performance and degradation in efficiency and reliability of the communication. In the presence of such an attack, the throughput decreases, end-to-end delay increases and packet delivery ratio decreases. Moreover, it may harm other network performance parameters. Hence, it becomes extremely essential to provide an effective and competent scheme to mitigate this attack in EIoT. In this paper, an intrusion detection scheme to protect EIoT environment against sinkhole attack is proposed, which is named as SAD-EIoT. In SAD-EIoT, the resource rich edge nodes (edge servers) perform the detection of different types of sinkhole attacker nodes with the help of exchanging messages. The practical demonstration of SAD-EIoT is also provided using the well known NS2 simulator to compute the various performance parameters. Additionally, the security analysis of SAD-EIoT is conducted to prove its resiliency against various types of SHAs. SAD-EIoT achieves around 95.83% detection rate and 1.03% false positive rate, which are considerably better than other related existing schemes. Apart from those, SAD-EIoT is proficient with respect to computation and communication costs. Eventually, SAD-EIoT will be a suitable match for those applications which can be used in critical and sensitive operations (for example, surveillance, security and monitoring systems).