Federated Deep Reinforcement Learning for THz-Beam Search with Limited CSI

Terahertz (THz) communication with ultra-wide available spectrum is a promising technique that can achieve the stringent requirement of high data rate in the next-generation wireless networks, yet its severe propagation attenuation significantly hinders its implementation in practice. Finding beam directions for a large-scale antenna array to effectively overcome severe propagation attenuation of THz signals is a pressing need. This paper proposes a novel approach of federated deep reinforcement learning (FDRL) to swiftly perform THz-beam search for multiple base stations (BSs) coordinated by an edge server in a cellular network. All the BSs conduct deep deterministic policy gradient (DDPG)-based DRL to obtain THz beamforming policy with limited channel state information (CSI). They update their DDPG models with hidden information in order to mitigate inter-cell interference. We demonstrate that the cell network can achieve higher throughput as more THz CSI and hidden neurons of DDPG are adopted. We also show that FDRL with partial model update is able to nearly achieve the same performance of FDRL with full model update, which indicates an effective means to reduce communication load between the edge server and the BSs by partial model uploading. Moreover, the proposed FDRL outperforms conventional non-learning-based and existing non-FDRL benchmark optimization methods

A Retrospective Cohort Study Comparing Stroke Recurrence Rate in Ischemic Stroke Patients With and Without Acupuncture Treatment.

Little was known about the effects of acupuncture on stroke recurrence. The aim of this study is to investigate whether ischemic stroke patients receiving acupuncture treatment have a decreased risk of stroke recurrence. A retrospective cohort study of 30,058 newly diagnosed cases of ischemic stroke in 2000 to 2004 was conducted based on the claims of Taiwan National Health Insurance Research Database. The use of acupuncture treatment and stroke recurrence were identified during the follow-up period from 2000 to 2009. This study compared the risk of stroke recurrence between ischemic stroke cohorts with and without acupuncture treatment by calculating adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of acupuncture associated with stroke recurrence in the Cox proportional hazard model. The stroke recurrence rate per 1000 person-years decreased from 71.4 without to 69.9 with acupuncture treatment (P < 0.001). Acupuncture treatment was associated with reduced risk of stroke recurrence (HR 0.88; 95% CI 0.84-0.91). The acupuncture effect was noted in patients with or without medical treatment for stroke prevention but its impact decreased with aging of stroke patients. Compared with stroke patients without acupuncture treatment and medication therapy, the hazard ratios of stroke recurrence for those had medication therapy only, acupuncture only, and both were 0.42 (95% CI 0.38-0.46), 0.50 (95% CI 0.43-0.57), and 0.39 (95% CI 0.35-0.43), respectively. This study raises the possibility that acupuncture might be effective in lowering stroke recurrence rate even in those on medications for stroke prevention. Results suggest the need of prospective sham-controlled and randomized trials to establish the efficacy of acupuncture in preventing stroke

Donorâ Acceptorâ Acceptor’s Molecules for Vacuumâ Deposited Organic Photovoltaics with Efficiency Exceeding 9%

Three vacuumâ deposited donorâ acceptorâ acceptor (dâ aâ a’) small molecule donors are studied with different side chains attached to an asymmetric heterotetracene donor block for use in high efficiency organic photovoltaics (OPVs). The donor with an isobutyl side chain yields the highest crystal packing density compared to molecules with 2â ethylhexyl or nâ butyl chains, leading to the largest absorption coefficient and short circuit current in an OPV. It also exhibits a higher fill factor, consistent with its preferred outâ ofâ plane molecular Ï â Ï stacking arrangement that facilitates charge transport in the direction perpendicular to the substrate. A power conversion efficiency of 9.3 ± 0.5% is achieved under 1 sun intensity, AM 1.5 G simulated solar illumination, which is significantly higher than 7.5 ± 0.4% of the other two molecules. These results indicate that side chain modification of dâ aâ a’ small molecules offers an effective approach to control the crystal packing configuration, thereby improving the device performance.Three vacuumâ deposited donorâ acceptorâ acceptor’s small molecule donors with different alkyl chain configurations (R1â R3) are synthesized and characterized to understand the side chain effect on organic photovoltaic (OPV) performance. The donor with an isobutyl (R3) chain yields the highest crystal packing density and largest short circuit current among the three molecules. Its preferred faceâ on molecular stacking orientation on the substrate leads to the highest fill factor. The optimized OPV structure achieves a power conversion efficiency (PCE) = 9.3 ± 0.5%.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/1/aenm201703603.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/2/aenm201703603-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144608/3/aenm201703603_am.pd

Invited; CMOS inverters and circuits based on oxide thin-film transistors

Thin-film transistors (TFTs) based on oxide semiconductors have the advantage of promising carrier mobilities and good switching characteristics, and they can be fabricated by low-temperature and scalable processes. Complementary metal-oxide-semiconductor (CMOS) technology employing oxide TFTs shows great potential in enabling flexible electronics with versatile functionalities and low-static power consumptions. Here flexible CMOS inverters comprising p-type SnO TFTs and n-type ZnO or IGZO TFTs integrated in three different configurations were implemented and compared, as shown in Fig. 1. First, the planar inverter comprising bottom-gated SnO and ZnO TFTs with a geometric aspect ratio, (W/L)p / (W/L)n, of 5 had a static voltage gain of ~ 10 V/V at a supplied voltage (VDD) of 10 V [1]. However, the gain decreased as the inverter was subjected to a mechanical tensile strain, which may be ascribed to the degradation of TFT mobilities. Please click Download on the upper right corner to see the full abstract

Structural and optical properties of ZnMgO nanostructures formed by Mg in-diffused ZnO nanowires

Abstract ZnMgO nanostructures with wurtzite phase were prepared by thermal diffusion of Mg into the ZnO nanowires. As ZnO light-emitting devices have been operated by using ZnMgO layers as energy barrier layers to confine the carriers, it is essential to realize the characterization of ZnMgO particularly. In this work, the Mg content in Zn 1Àx Mg x O alloy determined by X-ray diffraction (XRD) and photoluminescence (PL) shows a good coincidence. The variation of lattice constant and the blueshift of near-band-edge emission indicate that Zn 2+ ions are successfully substituted by Mg 2+ ions in the ZnO lattice. In Raman-scattering studies, the change of E 2 (high) phonon line shape in ZnO:Mg nanostructures reveals the microscopic substitutional disorder. In addition to the host phonons of ZnO, two additional bands around 383 and 510 cm À1 are presumably attributed to the Mg-related vibrational modes

PARENTAGE OF OVERLAPPING OFFSPRING OF AN ARBOREAL-BREEDING FROG WITH NO NEST DEFENSE: IMPLICATIONS FOR NEST SITE SELECTION AND REPRODUCTIVE STRATEGY

Overlapping offspring occurs when eggs are laid in a nest containing offspring from earlier reproduction. To unveil the parentage between overlapping offspring and parents is critical in understanding oviposition site selection and the reproductive strategies of parents. Amplectant pairs of an arboreal-breeding frog, Kurixalus eiffingeri, lay eggs in tadpole-occupied nests where offspring of different life stages (embryos and tadpoles) coexist. We used five microsatellite DNA markers to assess the parentage between parents and overlapping offspring. Results showed varied parentage patterns, which may differ from the phenomenon of overlapping egg clutches reported earlier. Parentage analyses showed that only 58 and 25% of the tadpole-occupied stumps were reused by the same male and female respectively, partially confirming our prediction. Re-nesting by the same individual was more common in males than females, which is most likely related to the cost of tadpole feeding and/or feeding schemes of females. On the other hand, results of parentage analyses showed that about 42 and 75 % of male and female respectively bred in tadpole-occupied stumps where tadpoles were genetically unrelated. Results of a nest-choice experiment revealed that 40% of frogs chose tadpole-occupied bamboo cups when we presented identical stumps, without or with tadpoles, suggesting that the habitat saturation hypothesis does not fully explain why frogs used the tadpole-occupied stumps. Several possible benefits of overlapping offspring with different life stages were proposed. Our study highlights the importance of integrating molecular data with field observations to better understand the reproductive biology and nest site selection of anuran amphibians

PARENTAGE OF OVERLAPPING OFFSPRING OF AN ARBOREAL-BREEDING FROG WITH NO NEST DEFENSE: IMPLICATIONS FOR NEST SITE SELECTION AND REPRODUCTIVE STRATEGY

Overlapping offspring occurs when eggs are laid in a nest containing offspring from earlier reproduction. To unveil the parentage between overlapping offspring and parents is critical in understanding oviposition site selection and the reproductive strategies of parents. Amplectant pairs of an arboreal-breeding frog, Kurixalus eiffingeri, lay eggs in tadpole-occupied nests where offspring of different life stages (embryos and tadpoles) coexist. We used five microsatellite DNA markers to assess the parentage between parents and overlapping offspring. Results showed varied parentage patterns, which may differ from the phenomenon of overlapping egg clutches reported earlier. Parentage analyses showed that only 58 and 25% of the tadpole-occupied stumps were reused by the same male and female respectively, partially confirming our prediction. Re-nesting by the same individual was more common in males than females, which is most likely related to the cost of tadpole feeding and/or feeding schemes of females. On the other hand, results of parentage analyses showed that about 42 and 75 % of male and female respectively bred in tadpole-occupied stumps where tadpoles were genetically unrelated. Results of a nest-choice experiment revealed that 40% of frogs chose tadpole-occupied bamboo cups when we presented identical stumps, without or with tadpoles, suggesting that the habitat saturation hypothesis does not fully explain why frogs used the tadpole-occupied stumps. Several possible benefits of overlapping offspring with different life stages were proposed. Our study highlights the importance of integrating molecular data with field observations to better understand the reproductive biology and nest site selection of anuran amphibians

Fabrication of blue top-emitting organic light-emitting devices with highly saturated color

Abstract Blue top-emitting organic light-emitting devices (TOLEDs) with highly saturated color were developed by microcavity effect. The device structure studied was glass/reflective silver/indium-tin oxide (ITO)/organic electroluminescent stack/semi-transparent cathode (calcium/silver). By changing the thicknesses of ITO and organic layers in the microcavity structure device doped with p-bis(p-N, Ndi-phenyl-aminostyryl)benzene (DSA-ph), highly saturated color with Commission Internationale de L'Eclairage chromaticity coordinates (CIE x;y ) of (0.14, 0.08) was obtained

Monitoring Resistance to Spinosad in the Melon Fly (Bactrocera cucurbitae) in Hawaii and Taiwan

Spinosad is a natural insecticide with desirable qualities, and it is widely used as an alternative to organophosphates for control of pests such as the melon fly, Bactrocera cucurbitae (Coquillett). To monitor the potential for development of resistance, information about the current levels of tolerance to spinosad in melon fly populations were established in this study. Spinosad tolerance bioassays were conducted using both topical applications and feeding methods on flies from field populations with extensive exposure to spinosad as well as from collections with little or no prior exposure. Increased levels of resistance were observed in flies from the field populations. Also, higher dosages were generally required to achieve specific levels of mortality using topical applications compared to the feeding method, but these levels were all lower than those used for many organophosphate-based food lures. Our information is important for maintaining effective programs for melon fly management using spinosad