Single- and Multimagnon Dynamics in Antiferromagnetic α\alpha-Fe2_2O3_3 Thin Films

Understanding the spin dynamics in antiferromagnetic (AFM) thin films is fundamental for designing novel devices based on AFM magnon transport. Here, we study the magnon dynamics in thin films of AFM $S=5/2$ $\alpha$-Fe$_2$O$_3$ by combining resonant inelastic x-ray scattering, Anderson impurity model plus dynamical mean-field theory, and Heisenberg spin model. Below 100 meV, we observe the thickness-independent (down to 15 nm) acoustic single-magnon mode. At higher energies (100-500 meV), an unexpected sequence of equally spaced, optical modes is resolved and ascribed to $\Delta S_z = 1$, 2, 3, 4, and 5 magnetic excitations corresponding to multiple, noninteracting magnons. Our study unveils the energy, character, and momentum-dependence of single and multimagnons in $\alpha$-Fe$_2$O$_3$ thin films, with impact on AFM magnon transport and its related phenomena. From a broader perspective, we generalize the use of L-edge resonant inelastic x-ray scattering as a multispin-excitation probe up to $\Delta S_z = 2S$. Our analysis identifies the spin-orbital mixing in the valence shell as the key element for accessing excitations beyond $\Delta S_z = 1$, and up to, e.g., $\Delta S_z = 5$. At the same time, we elucidate the novel origin of the spin excitations beyond the $\Delta S_z = 2$, emphasizing the key role played by the crystal lattice as a reservoir of angular momentum that complements the quanta carried by the absorbed and emitted photons.Comment: Accepted in Physical Review

AI-Aided Individual Emergency Detection System in Edge-Internet of Things Environments

Recently, many disasters have occurred in indoor places. In order to rescue or detect victims within disaster scenes, vital information regarding their existence and location is needed. To provide such information, some studies simply employ indoor positioning systems to identify each mobile device of victims. However, their schemes may be unreliable, since people sometimes drop their mobile devices or put them on a desk. In other words, their methods may find a mobile device, not a victim. To solve this problem, this paper proposes a novel individual monitoring system based on edge intelligence. The proposed system monitors coexisting states with a user and a smart mobile device through a user state detection mechanism, which could allow tracking through the monitoring of continuous user state switching. Then, a fine-grained localization scheme is employed to perceive the precise location of a user who is with a mobile device. Hence, the proposed system is developed as a proof-of-concept relying on off-the-shelf WiFi devices and reusing pervasive signals. The smart mobile devices of users interact with hierarchical edge computing resources to quickly and safely collect and manage sensing data of user behaviors with encryption by cipher-block chaining, and user behaviors are analyzed via the ensemble paradigm of three machine learning technologies. The proposed system shows 98.82% prevision for user activity recognition, and 96.5% accuracy for user localization accuracy is achieved

Integrated Management Strategy with Feasible Smartness over Heterogeneous IoT Environments

Recently, Internet of Things (IoT) applications have been increasingly deployed in smart domains, such as homes, buildings, and so on. A wide variety of smart devices and solutions bring improved lifestyles. However, current provider-oriented and individual application deployment leads to the separation of a smart domain into respective regions by providers and applications. Such heterogeneous environments hinder unified operation and the utilization of smart IoT applications. Therefore, this Article firstly addresses analyses on conventional smart domain technologies—smart home, smart building, etc.— and deployment in the real world with heterogeneous IoT technologies; then, a novel smart domain strategy for inter-cloud and inter-service operability and mobile-user-attached interactivity is proposed. Performance is compared in terms of user experience and service availability. Finally, numeric analyses are provided to prove the proposed strategy, and the proof-of-concept is presented to show feasibility and performances

Collaborative Reliable Event Transport Based on Mobile-Assisted Sensing in Urban Digital Twin

For urban digital twin, this paper comes up with a novel urban data acquisition scheme, denoted by collaborative reliable event transport (cRET), that conducts micro-scale sensing resolution in urban environments. cRET relies on battery-powered sensors with Bluetooth low-energy (BLE) modules and the smart mobile devices that people carry around urban places. However, the traditional data acquisition schemes with mobile assistance suffer from the poor communication channel quality of BLE. So, it is tough to achieve enough reliability of event observation. Hence, cRET utilizes overhearing-based collaboration among sensors to improve the data delivery ratio. It also could support reliable transmission over mobile devices despite high-speed moving. A proof-of-concept demonstrates that the reliability is improved by the overhearing and collaboration among sensors against low-channel conditions and a high moving speed of mobile devices, i.e., 30 km/h and more

Collaborative Reliable Event Transport Based on Mobile-Assisted Sensing in Urban Digital Twin

For urban digital twin, this paper comes up with a novel urban data acquisition scheme, denoted by collaborative reliable event transport (cRET), that conducts micro-scale sensing resolution in urban environments. cRET relies on battery-powered sensors with Bluetooth low-energy (BLE) modules and the smart mobile devices that people carry around urban places. However, the traditional data acquisition schemes with mobile assistance suffer from the poor communication channel quality of BLE. So, it is tough to achieve enough reliability of event observation. Hence, cRET utilizes overhearing-based collaboration among sensors to improve the data delivery ratio. It also could support reliable transmission over mobile devices despite high-speed moving. A proof-of-concept demonstrates that the reliability is improved by the overhearing and collaboration among sensors against low-channel conditions and a high moving speed of mobile devices, i.e., 30 km/h and more

Mobile-Based Sensing Scheme to Minimize Battery Power Consumption for Urban Monitoring Systems

In urban monitoring systems, mobile sensing is imperative to acquire data from sensors and relay them to a cloud server. Mobile devices can be used anytime and anywhere, enabling communication with pervasive sensing in various conditions to obtain the data. Reliable data acquisition has been required in urban monitoring systems from the macroscale to the microscale. However, a broadcast method for the data acquisition process may lead to the increased battery power consumption of mobile devices. Managing the battery power consumption of mobile devices is essential for reliable data acquisition. In this paper, we propose an urban monitoring system with an optimization algorithm in which a cloud server broadcasts a communication request that includes battery power consumption and the data acquisition quantity of mobile devices. Game theoretic optimization is formulated with a decision process. We derive a best response and Nash equilibrium for mobile communication with sensors and a cloud server. Evaluation results demonstrate that the proposed system can guarantee a low battery power consumption, as well as acquire the desired data quantity

Mobile-Based Sensing Scheme to Minimize Battery Power Consumption for Urban Monitoring Systems

In urban monitoring systems, mobile sensing is imperative to acquire data from sensors and relay them to a cloud server. Mobile devices can be used anytime and anywhere, enabling communication with pervasive sensing in various conditions to obtain the data. Reliable data acquisition has been required in urban monitoring systems from the macroscale to the microscale. However, a broadcast method for the data acquisition process may lead to the increased battery power consumption of mobile devices. Managing the battery power consumption of mobile devices is essential for reliable data acquisition. In this paper, we propose an urban monitoring system with an optimization algorithm in which a cloud server broadcasts a communication request that includes battery power consumption and the data acquisition quantity of mobile devices. Game theoretic optimization is formulated with a decision process. We derive a best response and Nash equilibrium for mobile communication with sensors and a cloud server. Evaluation results demonstrate that the proposed system can guarantee a low battery power consumption, as well as acquire the desired data quantity

Polymeric Micelles with pH-Responsive Cross-Linked Core Enhance In Vivo mRNA Delivery

Messenger RNA (mRNA) is emerging as a promising therapeutic modality for a variety of diseases. Because of the fragility and limited intracellular access of mRNA, the development of delivery technologies is essential for promoting the applicability of mRNA-based treatments. Among effective nanocarriers, polymeric micelles loading mRNA by polyion complex (PIC) formation with block catiomers have the potential to meet the delivery needs. Since PICs are relatively unstable in in vivo settings, herein, we constructed mRNA-loaded micelles having pH-responsive cross-linked cores by complexing mRNA with cis-aconitic anhydride-modified poly(ethylene glycol)-poly(l-lysine) (PEG-pLL(CAA)) block copolymers. The micelles were stable at physiological pH (pH 7.4) but achieved the complete release of the mRNA at endosomal pH (pH 5.5–4.5). The cross-linking also enhanced the stability of the micelles against disassembly from polyanions and protected the loaded mRNA from degradation by nucleases. Thus, the cross-linked micelles increased the delivery of mRNA to cancer cells, promoting protein expression both in vitro and in vivo. Our results highlight the potential of PEG-pLL(CAA)-based micelles for mRNA delivery

Selectively Regulating the Chiral Morphology of Amino Acid-Assisted Chiral Gold Nanoparticles with Circularly Polarized Light

Copyright © 2022American Chemical Society. Chiral nanomaterials have attracted increasing attention due to their versatile optical properties. Although circularly polarized (CP) light can serve as an inducer, it has negligible effects because of the short lifetime of the plasmonic states. Here, we propose that the site-selective chirality regulation on the morphology of cysteine (cys) amino acid-assisted chiral gold nanoparticles (cys-chiral AuNPs) can be realized through CP light irradiation. This can result in the increased or decreased circular dichroism (CD) signal intensity. The site-selective growth mechanism of the cys-chiral AuNPs is elucidated with light-matter interactions through the opposite rotation of right(R)/left(L) CP light. The site-selective chirality growth of the cys-chiral AuNPs is ascribed to the morphology evolution induced by the synergy of cys and R/L-CP light, which is clearly analyzed and elucidated with high CD intensities. This work provides a promising alternative strategy to produce high-chirality nanomaterials that can be applied in biomedicine and enantiomer photocatalytic reaction.11Nsciescopu

Agent-Based Multipath Management for Supporting Sink Mobility in Wireless Sensor Networks

In wireless sensor networks, sink mobility support is one of the essential functionalities in many applications. With continuous advancement, future applications will require not only sink mobility support but also high-performance data delivery service. Multipath routing is one of the promising technologies for improving data delivery performance by collaboratively using alternative or redundant multiple routing paths. However, existing multipath routing protocols had not dealt with sink mobility. As a result, they lead to bad performance in terms of energy efficiency due to the end-to-end path reconstruction. Consequently, a novel multipath management scheme is required thereby supporting sink mobility without performance degradation. In this paper, we propose a multipath management scheme for supporting sink mobility. The proposed scheme dynamically constructs multipath along the moving path of a sink. In addition, the proposed scheme provides the path shortening schemes according to the sink’s movement for reducing energy consumption. Our simulation results show that the proposed scheme is superior to existing path management schemes in terms of reliability and energy efficiency