Wi-Fi-based localization using received signal strength (RSS) with pedestrian dead reckoning (PDR) algorithm is widely used to track pedestrians in indoor environments. However, the unsatisfactory ...deployment of Wi-Fi access points (APs) in buildings and the unstable performance of PDR are still key problems that lead to low localization accuracy. In this paper, we make contributions on proposing a hybrid Wi-Fi and Bluetooth Low Energy (BLE) indoor localization system (ILS) based on an efficient BLE deployment strategy and hierarchical topological fingerprinting (HTF). For the BLE deployment strategy, we deploy BLE beacons in places that do not have clear Wi-Fi signals for localization. This efficiently increases the localization accuracy. For HTF, we hierarchically localize targets based on a topological fingerprint (TF) map. First of all, we quickly localize the room in which the target is located by Dendogram-based support vector machine (DSVM). Then, the specific position of the target is estimated by fusing Wi-Fi and BLE signals with the TF map. The new BLE-based fingerprinting algorithm is used to localize targets in environments sparsely populated by BLE beacons. We conduct physical experiments in a real building. The experimental results demonstrate that the beacons deployed based on our proposed deployment strategy results in greater localization accuracy. Furthermore, the HTF approach performs better than the other commonly used localization methods.
Indoor localization based on received signal strength (RSS) will result in a decreased precision after the environment changes. In this paper, we develop an adaptive wireless indoor localization ...system (ILS) for dynamic environments. The system consists of the following two components: an automated database updating process and a new fingerprinting algorithm called adaptive signal model fingerprinting (ASMF). In the ILS, a self-locating mobile robot is set up to continuously collect RSS measurement data within the localization space for autonomously updating the fingerprint database. ASMF is designed to reduce the time consumption and the amount of RSS data needed for updating the database. The fingerprint of the signal in ASMF is constructed by the position of the beacons and three signal models, which can be duly corrected based on the regression and optimization algorithm. Finally, we propose experiments for positioning targets in the static and dynamic environments and compare the results of the ASMF algorithm with traditional trilateration and k-nearest-neighbor fingerprinting algorithms. The experimental results demonstrate that the ASMF-based ILS provides much better performance in both static and dynamic environments; furthermore, the positioning accuracy can be actually maintained by the autonomous updated ASMF database.
Human adenovirus type 3 (HAdV-3) and 7 (HAdV-7) cause significant morbidity and develop severe complications and long-term pulmonary sequelae in children. However, epidemiologic reports have ...suggested that nearly all highly severe or fatal adenoviral diseases in children are associated with HAdV-7 rather than HAdV-3. Here, we conduct in-depth investigations to confirm and extend these findings through a comprehensive series of assays in vitro and in vivo as well as clinical correlates.
A total of 8248 nasopharyngeal aspirate (NPA) samples were collected from hospitalized children with acute respiratory infections in Children's Hospital of Chongqing Medical University from June 2009 to May 2015. Among 289 samples that tested positive for HAdVs, clinical data of 258 cases of HAdV-3 (127) and HAdV-7 (131) infections were analyzed. All HAdV-positive samples were classified by sequencing the hexon and fiber genes, and compared with clinical data and virological assays. We also performed in vitro assays of virus quantification, viral growth kinetics, competitive fitness, cytotoxicity and C3a assay of the two strains. Mouse adenovirus model was used to evaluate acute inflammatory responses.
Clinical characteristics revealed that HAdV-7 infection caused more severe pneumonia, toxic encephalopathy, respiratory failure, longer mean hospitalization, significantly lower white blood cell (WBC) and platelet counts, compared to those of HAdV-3. In cell culture, HAdV-7 replicated at a higher level than HAdV-3, and viral fitness showed significant differences as well. HAdV-7 also exhibited higher C3a production and cytotoxic effects, and HAdV-7-infected mice showed aggravated pathology and higher pulmonary virus loads, compared to HAdV-3-infected mice. Macrophages in BALF remained markedly high during infection, with concomitant increase in pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, and IL-6), compared HAdV-3 infection.
These results document that HAdV-7 replicates more robustly than HAdV-3, and promotes an exacerbated cytokine response, causing a more severe airway inflammation. The findings merit further mechanistic studies that offer the pediatricians an informed decision to proceed with early diagnosis and treatment of HAdV-7 infection.
Single-stranded DNA (ssDNA)-binding protein (SSB) plays a crucial role in DNA replication, repair, and recombination as well as replication fork restarts. SSB is essential for cell survival and, ...thus, is an attractive target for potential antipathogen chemotherapy. Whether naturally occurring products can inhibit SSB remains unknown. In this study, the effect of the flavonols myricetin, quercetin, kaempferol, and galangin on the inhibition of
SSB (PaSSB) was investigated. Furthermore, SSB was identified as a novel quercetin-binding protein. Through an electrophoretic mobility shift analysis, myricetin could inhibit the ssDNA binding activity of PaSSB with an IC
of 2.8 ± 0.4 μM. The effect of quercetin, kaempferol, and galangin was insignificant. To elucidate the flavonol inhibition specificity, the crystal structure of PaSSB complexed with the non-inhibitor quercetin was solved using the molecular replacement method at a resolution of 2.3 Å (PDB entry 7VUM) and compared with a structure with the inhibitor myricetin (PDB entry 5YUN). Although myricetin and quercetin bound PaSSB at a similar site, their binding poses were different. Compared with myricetin, the aromatic ring of quercetin shifted by a distance of 4.9 Å and an angle of 31
for hydrogen bonding to the side chain of Asn108 in PaSSB. In addition, myricetin occupied and interacted with the ssDNA binding sites Lys7 and Glu80 in PaSSB whereas quercetin did not. This result might explain why myricetin could, but quercetin could not, strongly inhibit PaSSB. This molecular evidence reveals the flavonol inhibition specificity and also extends the interactomes of the natural anticancer products myricetin and quercetin to include the OB-fold protein SSB.
Mobile sensor node deployment and power management are important issues in the wireless sensor network system. This study designs a mobile sensor node platform to achieve a highly accurate ...localization mechanism by using ultrasonic, dead reckoning, and radio frequency information which is processed through a particle filter algorithm. Mobile sensor node with accurate localization ability is of great interest to basic research works and applications, such as sensor deployment, coverage management, dynamic power management, etc. In this paper, we propose an efficient mobile sensor node deployment method, grid deployment, where the map is divided into multiple individual grids and the weight of each grid is determined by environmental factors such as predeployed nodes, boundaries, and obstacles. The grid with minimum values is the goal of the mobile node. We also design an asynchronous power management strategy in our sensor node to reduce power consumption of the sensor network. Several factors such as probability of event generation, battery status, coverage issues, and communication situations have also been taken into consideration. In network communication, we propose an asynchronous awakening scheme so that each node is free to switch on or off its components according to observed event statistics and make a tradeoff between communication and power consumption. The deepest sleep state period is determined by the residual power. By combining these methods, the power consumption of the sensor node can be reduced.
The aim of this paper is to accurately predict the evolution of wheel profile wear and related vehicle dynamics for high-speed trains by considering the stochastic wheel/rail interactions, which ...experience quite variants with time and along long distant high-speed lines in China. These variants include the rail profiles, track geometries, track irregularities and interface characteristics associated with each segment of track. Mathematic normal distribution is introduced to rationally describe these stochastic parameters. The Archard wear model and FASTSIM algorithm are employed to determine the wear within a contact patch of the wheel, and a strategy based on the travel distance of wheel is used in the profile updating procedure. Referring to previous works, a nonlinear multibody vehicle system model is built and its accuracy was validated by lab tests. In the numerical simulation, three methods of stochastic matching of parameters in wheel/rail interactions are performed, including all constant parameters, only stochastic rail profiles, and both stochastic rail profiles and stochastic track parameters. Comparative studies show that there are good agreements in the wear evaluation of wheel profile between the simulated and measured results, as well as the behavior evaluation of vehicle dynamics in a total travel distance of 300,000km. It is essential, therefore, to consider the stochastic matchings of parameters in the wheel/rail interaction for predicting the wheel profile wear and vehicle dynamics evolution of high-speed trains.
•The stochastic wheel/rail interactions are considered in the simulation.•Vehicle dynamics and wheel profile wear evolutions were obtained and validated.
An emerging approach is utilizing the line‐of‐sight gravity difference (LGD) between the twin Gravity Recovery and Climate Experiment Follow‐On (GFO) satellites to refine the temporal resolution of ...water storage estimates from 1 month to days, thus making the data applicable to transient extreme climate events like floods. However, applying the approach to medium‐scale climate events (with mass changes of several tens of gigatons) is challenging due to surrounding signal contamination and low signal‐to‐noise ratios. To address this problem, this study develops an improved algorithm accounting for peripheral signal sources and temporal correlations in mass variation. Two floods in July 2021 in Western Europe and Central China (CC) are chosen as case studies to demonstrate our approach's applicability to moderate floods in complex hydrological settings. The results present the temporal progression of the floods up to a maximum of ∼40 Gt with a scale of 3–5 days. However, the GFO‐derived water gain in CC is much lower than expected values from land surface models, indicating a mass deficit during the flood. We find that the potent manipulation of water resources by human activities might impact the predictive capabilities of these models, thereby misrepresenting the hydrological evolution during the flood event. This study refines the viability of applying GFO data to restore transient dynamics characterizing extreme climate events of ∼20 Gt magnitude. We also provide insights on the use of LGD data for high‐temporal‐resolution estimation of water storage changes and underscore the non‐negligible influence of human interventions on short‐term hydrological dynamics.
Key Points
Flood monitoring based on the Gravity Recovery and Climate Experiment (GRACE) Follow‐On laser and microwave ranging observations with 3–5 days resolution
Two 2021 summer floods of about 40 gigatons in Western Europe and Central China are compared
GRACE Follow‐On's flood detectability has been enhanced to detect floods as small as 16 gigatons
In this paper, a service-oriented multiagent system (SoMAS) for the control and analysis of the cyber-physical system (CPS) in manufacturing automation utilizing a noncontact dynamic obstacle ...avoidance seven-DoF robot arm is presented. The interfaces of the services which the robot arm subsystem should provide to fully exploit its capability are identified. Specifically, the services of moving, object recognition, object fetching, and safety of human-robot interaction are considered as the fundamental functionalities that the robot arm should provide. The way to evaluate the quality of services (QoS) for the robot arm subsystem is also explained. To build such a robot arm subsystem, the system architecture is proposed. Also, implementation for the subsystem which includes: 3-D model-based object recognition, grasp database for object fetching, and online noncontact obstacle avoidance for the safety of human-robot interaction is provided. The experimental results demonstrate that the capability of 3-D model-based object recognition, object fetching, and dynamic collision avoidance are successfully implemented.
Intelligent service robot development is an important and critical issue for human community applications. With the diverse and complex service needs, the perception and navigation are essential ...subjects. This investigation focuses on the synergistic fusion of multiple sensors for an intelligent service robot that not only performs self-localization and mapping but also detects moving objects or people in the building it services. First of all, a new augmented approach of graph-based optimal estimation was derived for concurrent robot postures and moving object trajectory estimate. Moreover, all the moving object detection issues of a robot's indoor navigation are divided and conquered via multisensor fusion methodologies. From bottom to up, the estimation fusion methods are tactically utilized to get a more precise result than the one from only the laser ranger or stereo vision. Furthermore, for solving the consistent association problem of moving objects, a covariance area intersection belief assignment is applied for motion state evaluation and the complementary evidences such as kinematics and vision features are both synergized together to enhance the association efficiency with the evidence fusion method. The proof of concept with experiments has been successfully demonstrated and analyzed.
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