Efficient wireless reprogramming through reduced bandwidth usage and opportunistic sleeping

Wireless reprogramming of a sensor network is useful for uploading new code or for changing the functionality of existing code. Reprogramming may be done multiple times during a node’s lifetime and therefore a node has to remain receptive to future code updates. Existing reprogramming protocols, including Deluge, achieve this by bundling the reprogramming protocol and the application as one code image which is transferred through the network. The reprogramming protocol being complex, the overall size of the program image that needs to be transferred over the wireless medium increases, thereby increasing the time and energy required for reprogramming a network. We present a protocol called Stream that significantly reduces this bloat by using the facility of having multiple code images on the node. It pre-installs the reprogramming protocol as one image and equips the application program with the ability to listen to new code updates and switch to this image. For a sample application, the increase in size of the application image is 1 page (48 packets of 36 bytes each) for Stream and 11 pages for Deluge. Additionally, we design an opportunistic sleeping scheme whereby nodes can sleep during the period when reprogramming has been initiated but has not yet reached the neighborhood of the node. The savings become significant for large networks and for frequent reprogramming. We implement Stream on Mica2 motes and conduct testbed and simulation experiments to compare delay and energy consumption for different network sizes with respect to the state-of-the-art Deluge protocol.     

Multi‐“Color” Delineation of Bone Microdamages Using Ligand‐Directed Sub‐5 nm Hafnia Nanodots and Photon Counting CT Imaging

The early detection of bone microdamages is crucial to make informed decisions about the therapy and taking precautionary treatments to avoid catastrophic fractures. Conventional computed tomography (CT) imaging faces obstacles in detecting bone microdamages due to the strong self‐attenuation of photons from bone and poor spatial resolution. Recent advances in CT technology as well as novel imaging probes can address this problem effectively. Herein, the bone microdamage imaging is demonstrated using ligand‐directed nanoparticles in conjunction with photon counting spectral CT. For the first time, Gram‐scale synthesis of hafnia (HfO₂) nanoparticles is reported with surface modification by a chelator moiety. The feasibility of delineating these nanoparticles from bone and soft tissue of muscle is demonstrated with photon counting spectral CT equipped with advanced detector technology. The ex vivo and in vivo studies point to the accumulation of hafnia nanoparticles at microdamage site featuring distinct spectral signal. Due to their small sub‐5 nm size, hafnia nanoparticles are excreted through reticuloendothelial system organs without noticeable aggregation while not triggering any adverse side effects based on histological and liver enzyme function assessments. These preclinical studies highlight the potential of HfO₂‐based nanoparticle contrast agents for skeletal system diseases due to their well‐placed K‐edge binding energy.     

Synthesis of CdZnTeSe single crystals for room temperature radiation detector fabrication: mitigation of hole trapping effects using a convolutional neural network

Journal of Materials Science: Materials in Electronics - In this article, we report the growth of Cd0.9Zn0.1Te0.97Se0.03 (CZTS) wide bandgap semiconductor single crystals for room temperature...     

Effects of phase noise on performance of OFDM systems using an ICI cancellation scheme

This paper investigates the effects of phase noise on the performance of orthogonal frequency division multiplexing (OFDM) systems using an intercarrier interference (ICI) cancellation scheme. In this case, the common phase error (CPE) and ICI caused by phase noise depend on the overall spectrum of each weighted group of subcarriers rather than on the spectrum of each individual subcarrier. This means that the system performance can be improved by filtering the phase noise to fit a particular spectrum. It is shown that the ICI cancellation scheme can significantly improve the bit error rate (BER) performance in the presence of phase noise.     

Web of cybersecurity: Linking,locating, and discovering structured cybersecurity information

Cybersecurity is one of the main concerns of many organizations today, and accessibility to cybersecurity information in a timely manner is crucial to maintaining cybersecurity. Various repositories of cybersecurity‐related information are publicly available on the Internet. However, users are unaware of many of them, and it is impractical for them to keep track of all of them. Cybersecurity information stored in these repositories must be able to be located and accessed by the parties who need it. To address this issue, this paper proposes a mechanism of linking, locating, and discovering various cybersecurity information to improve its accessibility in a timely manner. This mechanism allows us to locate various cybersecurity information having different schemata by generating metadata with which a list of cybersecurity information is managed. The information structure incorporated in this mechanism is unique, and it makes our mechanism flexible and extensible. The structure consists of categories and formats that are linked to each other. The mechanism can propagate information updates to minimize the risk of obsolete information. This paper also introduces a prototype of the mechanism to demonstrate its feasibility, and it analyzes the mechanism's extensibility, scalability, and information credibility. Through this study, we aim to improve the accessibility of cybersecurity information on the Internet and facilitate information sharing beyond organizational borders, with the eventual goal of creating a web of cybersecurity.