Performance Limits and Geometric Properties of Array Localization

Location-aware networks are of great importance and interest in both civil and military applications. This paper determines the localization accuracy of an agent, which is equipped with an antenna array and localizes itself using wireless measurements with anchor nodes, in a far-field environment. In view of the Cram\'er-Rao bound, we first derive the localization information for static scenarios and demonstrate that such information is a weighed sum of Fisher information matrices from each anchor-antenna measurement pair. Each matrix can be further decomposed into two parts: a distance part with intensity proportional to the squared baseband effective bandwidth of the transmitted signal and a direction part with intensity associated with the normalized anchor-antenna visual angle. Moreover, in dynamic scenarios, we show that the Doppler shift contributes additional direction information, with intensity determined by the agent velocity and the root mean squared time duration of the transmitted signal. In addition, two measures are proposed to evaluate the localization performance of wireless networks with different anchor-agent and array-antenna geometries, and both formulae and simulations are provided for typical anchor deployments and antenna arrays.Comment: to appear in IEEE Transactions on Information Theor

Negative Emotion Recognition Algorithm of Network Catchwords Based on Language Feature Dimension

The traditional negative emotion recognition algorithm has a limited language feature dimension, which leads to the inaccuracy of negative emotion recognition. In order to improve the identification and analysis of emotion in network buzzwords, the back propagation of error (BP) and the restricted Boltzmann machine (RBM) algorithms are adopted to effectively solve the problem of insufficient data for emotion analysis in different contexts. First, a method is proposed to identify negative emotions, and a deep neural network (DNN) model is constructed. Then, experiments were carried out, which used manually labeled data sets and divided them into different emotion categories, and which compared the BP algorithm, Gaussian Mixture Model (GMM) and Hidden Markov Model (HMM) for negative emotion recognition of online buzzwords. The experimental results show that the DNN model performs well in the recognition of anger, sadness, fear and disgust, with the accuracy reaching 93.56%, 93.58%, 89.84% and 88.53% respectively, which is obviously superior to the other three methods. The designed DNN model has a potential application prospect in the negative emotion recognition of online buzzwords, which can be further popularized in the future

Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11x1010 Jones due to the simultaneously suppressed noise and enhanced gain

Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11x1010 Jones due to the simultaneously suppressed noise and enhanced gain

Comfort-Centered Design of a Lightweight and Backdrivable Knee Exoskeleton

This paper presents design principles for comfort-centered wearable robots and their application in a lightweight and backdrivable knee exoskeleton. The mitigation of discomfort is treated as mechanical design and control issues and three solutions are proposed in this paper: 1) a new wearable structure optimizes the strap attachment configuration and suit layout to ameliorate excessive shear forces of conventional wearable structure design; 2) rolling knee joint and double-hinge mechanisms reduce the misalignment in the sagittal and frontal plane, without increasing the mechanical complexity and inertia, respectively; 3) a low impedance mechanical transmission reduces the reflected inertia and damping of the actuator to human, thus the exoskeleton is highly-backdrivable. Kinematic simulations demonstrate that misalignment between the robot joint and knee joint can be reduced by 74% at maximum knee flexion. In experiments, the exoskeleton in the unpowered mode exhibits 1.03 Nm root mean square (RMS) low resistive torque. The torque control experiments demonstrate 0.31 Nm RMS torque tracking error in three human subjects.Comment: 8 pages, 16figures, Journa

An efficient mutagenesis system to improve the propamocarb tolerance in Lecanicillium lecanii (Zimmermann) Zare & Gams

Lecanicillium lecanii (Zimmermann) Zare & Gams is used as an effective biopesticide for the control of sap-sucking insect pests on agricultural crops. However, low fungicide tolerance limits its large-scale field application. To improve the propamocarb tolerance in L. lecanii, a composite mutagenesis system was established by using UV-light (U), N-Methyl-N′-nitro-N-nitrosoguanidine (NTG) (N) and N+ ion-beam (I). The permutation type of three agents was a consecutive mutagenesis treatment (I/N/U) after an intermittent treatment (U + N + I). The “U” mutagenesis was performed at 254 nm for 60 s and at a distance of 45 cm under a 20 W germicidal lamp, the “N” mutagenesis was performed at a concentration of 1.0 mg/mL NTG for 60 min, and the “I” mutagenesis was performed by low energy N+ ion-beam using a dose of 10 × 1013 ions/cm2 at 30 keV. This composite mutagenesis system was recorded as the “U + N + I + I/N/U,” and then the mutagenesis efficiency in improving propamocarb tolerance was assessed by analyzing changes of mutants in the propamocarb sensitivity, mitotic stability, mycelial growth speed on plates or in liquid, sporulation on plates or aphids, conidial germination, 50% lethal concentration (LC50) and 50% lethal time (LT50) to aphids, lipid constituent and cell membrane permeability and control against aphids in the presence or absence of propamocarb. Compared to the wild-type isolate with a 50% effective concentration (EC50) value of 503.6 μg/mL propamocarb, the Ll-IC-UNI produced by the “U + N + I + I/N/U” had the highest EC50 value of 3576.4 μg/mL and a tolerance ratio of 7.1. The mutant was mitotically stable in 20-passage cultivation and did not show any unfavorable changes in growth and virulence indicators. The mutant showed the highest ability to resist or avoid the damaging effects of propamocarb as reflected by the alternations of lipid constituents and membrane permeability. The interval time for applying fungal agent was significantly shortened in this mutant after spraying a field recommended dose of 550 μg/mL propamocarb. In conclude, the “U + N + I + I/N/U” composite mutagenesis mode was efficient and useful to improve the propamocarb-tolerance of L. lecanii and the obtained Ll-IC-UNI could have commercial potential for field application

Fringe Visibility Enhanced Extrinsic Fabry-Perot Interferometer using a Graded Index Fiber Collimator

We report a fringe visibility-enhanced extrinsic Fabry-Perot interferometer (EFPI) by fusion splicing a quarter-pitch length of a graded-index fiber (GIF) to the lead-in single mode fiber (SMF). The performance of the GIF collimator is theoretically analyzed using a ray matrix model and experimentally verified through beam divergence angle measurements. The fringe visibility of the GIF-collimated EFPI is measured as a function of the cavity length and compared with that of a regular SMF-EFPI. At the cavity length of 500 μm, the fringe visibility of the GIF-EFPI is 0.8, while that of the SMF-EFPI is only 0.2. The visibility-enhanced GIF-EFPI may provide a better signal-to-noise ratio (SNR) for applications where a large dynamic range is desired

Th17 i IL-17 osiągają wyższe stężenia w przebiegu martwicy głowy kości udowej i są dodatnio skorelowane z nasileniem bólu

Objective: Synovitis associated with osteonecrosis of the femoral head (ONFH) is responsible for several clinical symptoms. However, the mechanisms underlying synovitis and the inflammatory environment remain unclear. This study analyzed the proinflammatory mediation expression of IL-17 and Th17, which perform key functions in regulating inflammatory processes in the inflamed synovium and peripheral blood in ONFH. Methods: Synovial fluid from the hips of 23 patients and 5 controls was collected during surgery, and peripheral blood samples were obtained from 34 patients and 9 controls. The expression of IL-17 in the synovium was detected by immunohistochemistry, and the levels of Th17 and IL-17 in the blood were measured by flow cytometry and ELISA. Pain assessment was performed for all the patients and controls. Results: An inflamed synovium was characterized by increased leukocyte infiltration and IL-17 expression in comparison with the control. Preoperative levels of Th17 and IL-17 were significantly higher in the peripheral blood of the ONFH group than those in the controls. The symptoms were also positively correlated with the Th17 levels of the ONFH patients. Conclusion: Th17 cells were recruited to an inflamed synovium, and inflammatory cytokine IL-17 was expressed at an increased level in the hip synovium of ONFH patients, which possibly contributed to clinical syndrome development. Overall, this study will help in identifying new therapeutic strategies for ONFH, especially the targeting of IL-17 to decrease inflammation and pain. Wstęp: Zapalenie błony maziowej związane z martwicą głowy kości udowej (osteonecrosis of the femoral head; ONFH) odpowiada za kilka objawów klinicznych, jednak mechanizmy leżące u podstaw zapalenia błony maziowej oraz środowisko zapalne pozostają niejasne. W niniejszym badaniu poddano analizie ekspresję mediatora zapalenia IL-17 na limfocytach Th17, które pełnią kluczową rolę w regulowaniu procesów zapalnych w objętej stanem zapalnym błonie maziowej i krwi obwodowej w przebiegu ONFH. Materiał i metody: Podczas zabiegów operacyjnych pobrano maź stawową ze stawów biodrowych 23 pacjentów i 5 osób z grupy kon­trolnej, natomiast próbki krwi obwodowej uzyskano od 34 pacjentów i 9 osób z grupy kontrolnej. Ekspresję IL-17 w błonie maziowej wykrywano za pomocą metody immunohistochemicznej, a stężenie Th17 i IL-17 we krwi mierzono metodą cytometrii przepływowej i metodą ELISA. U wszystkich pacjentów i osób z grupy kontrolnej oceniono parametr bólu. Wyniki: Cechą charakterystyczną objętej stanem zapalnym błony maziowej był wzrost nacieczenia limfocytarnego i ekspresji IL-17 w porównaniu z grupą kontrolną. Stężenie Th17 i IL-17 przed wykonaniem zabiegów operacyjnych było znacząco wyższe we krwi obwodowej pacjentów z martwicą głowy kości udowej niż grupy kontrolnej. Również objawy były u tych pacjentów dodatnio skorelowane z poziomem Th17. Wnioski: Limfocyty Th17 były rekrutowane do objętej stanem zapalnym błony maziowej, a cytokina zapalna IL-17 ulegała ekspresji na zwiększonym poziomie w błonie maziowej stawu biodrowego pacjentów z martwicą głowy kości udowej, co prawdopodobnie przyczyniło się do rozwoju zespołu objawów klinicznych. Uogólniając, niniejsze badanie może pomóc zidentyfikować nowe strategie terapeutyczne w martwicy głowy kości udowej, w szczególności ukierunkowane na IL-17 w celu zmniejszenia stanu zapalnego i bólu