Optimal Quality-of-Service Scheduling for Energy-Harvesting Powered Wireless Communications

XiaojingChen, Wei Ni, Xin Wang, YichuangSun, “Optimal Quality-of-Service Scheduling for Energy-Harvesting Powered Wireless Communications”, IEEE Transactions on Wireless Communications, Vol. 15 (5): 3269-3280, January 2016. © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, a new dynamic string tautening algorithm is proposed to generate the most energy-efficient off-line schedule for delay-limited traffic of transmitters with non-negligible circuit power. The algorithm is based on two key findings that we derive through judicious convex formulation and resultant optimality conditions, specifies a set of simple but optimal rules, and generates the optimal schedule with a low complexity of O(N2) in the worst case. The proposed algorithm is also extended to on-line scenarios, where the transmit schedule is generated on-the-fly. Simulation shows that the proposed algorithm requires substantially lower average complexity by almost two orders of magnitude to retain optimality than general convex solvers. The effective transmit region, specified by the tradeoff of the data arrival rate and the energy harvesting rate, is substantially larger using our algorithm than using other existing alternatives. Significantly more data or less energy can be supported in the proposed algorithm.Peer reviewedFinal Accepted Versio

Clinical benefit of dexmedetomidine in combination with dezocine as epidural anesthesia during cesarean delivery for pregnant women with gestational diabetes mellitus

Purpose: To investigate the clinical benefit of dexmedetomidine (DEX) when used in combination with dezocine as epidural anesthesia during cesarean delivery for puerperae with gestational diabetes mellitus (GDM).Methods: A total of 120 puerperae with GDM admitted to The Fourth Hospital of Shijiazhuang (Obstetrics and Gynecology Hospital Affiliated to Hebei Medical University, Shijiazhuang City, China) who underwent cesarean delivery from January 2019 to January 2020 were randomly assigned to groups A and B, with 60 patients per group. Epidural anesthesia with dezocine was used on patients in both groups, while DEX was added for patients in group A. Comparison was made between the 2 groups with regard to pregnancy outcomes, pain scores, maternal and infant blood glucose levels, hemodynamic indices, hormonal levels and adverse reaction rates (ARR).Results: Patients in group A had significantly better maternal and infant outcomes (p < 0.05), lower maternal postoperative pain scores (p < 0.05), lower maternal postoperative blood glucose levels (p < 0.001), higher infant postoperative blood glucose levels (p < 0.001). Furthermore, maternal incidence of adverse reactions in group A was lower than in group B (p <0.05). At the time point of 0.5 h after anesthesia and operation, the hemodynamic indices of puerperae in group A were significantly more stable, and levels of estradiol and prolactin were higher, relative to those in group B (p < 0.05). However, group A had a lower chemotaxin levels at immediate postoperative period and 1 day after operation than group B (p < 0.05).Conclusion: The combination of DEX and dezocine for epidural anesthesia stabilizes hemodynamics, improves hormone levels and lowers the incidence of adverse reactions in puerperae with GDM, thereby potentially ensuring better pregnancy outcomes and well-controlled blood glucose levels. Therefore, this strategy for epidural anesthesia has potentials for use in clinical practice

Consequences of drought, flooding, and insect herbivory on the distributions of closely related willow and poplar (Salicaceae) species across hydrologic gradients in Minnesota wetlands

University of Minnesota Ph.D. dissertation. September 2016. Major: Ecology, Evolution and Behavior. Advisor: Jeannine Cavender-Bares. 1 computer file (PDF); ix, 120 pages.Understanding the mechanisms underlying species diversity patterns is a central and long-standing issue in ecology. Beta diversity, the variances in species composition among sites, is an important aspect of species diversity that links local diversity patterns to regional diversity patterns. One of the community assembly processes that known to influence beta diversity is environmental filtering. Besides environmental filtering, biotic interactions can also affect beta diversity, if biotic factors exert differential effects on species performances across environmental gradients. Contributions of different community assembly processes to beta diversity can be tested with multiple approaches. First, experimental approaches allow direct tests of effects of abiotic and biotic factors on species performances across environmental gradients. Second, functional traits can be used to infer the community assembly processes underlying species diversity patterns, as differences in performance responses between species are caused by differences in relevant traits. Last, closely related species tend to (but not always) share similar ecological attributes; therefore, phylogenetic information may be used to predict functional traits and infer community assembly processes. This dissertation examined the effect of environmental filtering and insect herbivory on distributions of 14 willow and poplar species across hydrologic gradients in Central Minnesota, combining field and greenhouse experiments, functional traits data, and phylogenetic analyses. At our study site, Cedar Creek Ecosystem Science Reserve, the species showed differential distributions across a water table depth gradient, suggesting environmental filtering mediated by water stresses likely caused habitat segregation among species. Furthermore, species in the Salicaceae family are known to host a variety of insect herbivores, which makes insect herbivory another possible process influencing beta diversity among the Salicaceae communities. Chapter 1 tested environmental filtering in the Salicaceae species using a field experimental test. Cuttings of the 14 species were transplanted into 40 common gardens established along water table depth gradients in the field, where competition was minimized and herbivory was controlled. Species fitness response to the hydrologic environment was estimated based on cumulative growth and survival over two years using aster fitness models. Variation in nine drought and flooding tolerance traits were examined; these traits were expected to contribute to performance based on a priori understanding of plant function in relation to water availability and stress. Fitness variation of each species in the field experiment was used to model their water table depth optima. These optima predicted 75% of the variation in species observed hydrologic niches, based on peak abundances in naturally assembled communities in the surrounding region. Multiple traits associated with water transport efficiency and with water stress tolerance were correlated with species hydrologic niches, but they did not necessarily covary with each other. As a consequence, species occupying similar hydrologic niches had different combinations of trait values. Moreover, individual traits were less phylogenetically conserved than species hydrologic niches or integrated water stress tolerance as determined by multiple traits. In conclusion, differential fitness among species along hydrologic gradients is the consequence of multiple traits associated with water transport and water stress tolerance, expressed in different combinations by different species. Varying environmental tolerances, in turn, play a critical role in driving niche segregation among close relatives along hydrologic gradients. In chapter 2, the effect of insect herbivory on the growth of the Salicaceae species across hydrologic gradients was examined using the same common garden experiment mentioned above. An insect exclusion treatment was performed nested within the gardens, by installing real and sham cages to individual experimental plants and comparing species growth in the different cage treatments. Concentrations of nitrogen, carbon, and two groups of defense compounds, phenolic glycosides and condensed tannins in leaves were measured, and phylogenetic signals in these foliar traits were analyzed. The results showed that insect herbivory reduced plant growth, was different between species, and varied across the water table depth gradient in a hump-shaped manner. However, herbivory did not promote habitat segregation among the species because there was no interaction effect between species and water table depth on either herbivory damages or the cage treatment effect on growth. Furthermore, variations in leaf traits could partially explain the variation in herbivory between species but not variation across hydrologic gradients. Last, closely related species did not share similar defense traits: although secondary metabolite richness was phylogenetically conserved, the concentrations of the defense compounds and nitrogen were not. In conclusion, although insect herbivory did not promote beta diversity among the Salicaceae communities across hydrologic gradients, the dissimilarity in defense chemistry might promote the coexistence of close relatives within local communities through density-dependent effects. In the last chapter, a greenhouse experiment was performed to examine responses of growth and physiological traits in seven willow (genus Salix) species to a six-week long flooding treatment followed by a six-week long recovery period. These seven species were selected to represent the full ranges of mean water table depth and season water table depth fluctuation in the natural habitats of the 14 species. The flooding treatment increased plant growth and carbon assimilation by improving plant water status: plants received the flooding treatment showed higher stomatal conductance and predawn leaf water potential than plants received the control treatment. Furthermore, species distributed in wetter habitats had higher stem growth rate in the flooding treatment; and the species distributed in habitats with greater water table depth fluctuations showed greater variations in growth between the flooding and the recovery period. The results of this experiment suggest differential tolerances to flooding and water table depth fluctuation may contribute to habitat segregation among the species

Provisioning quality-of-service to energy harvesting wireless communications

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Energy harvesting (EH) is an innovative way to build long-term and self-sustainable wireless networks. However, an inconstant EH rate may have an adverse effect on the quality-of-service (QoS) of wireless traffic, such as packet delay and error. In this article we discuss techniques that provide QoS to EH powered wireless communications. A new "dynamic string tautening" method is presented to produce the most energy efficient schedule with substantially lower complexity, compared to convex optimization techniques. The method adapts to the bursty arrivals of wireless traffic and harvested energy, and ensures that delay-sensitive data will be delivered by deadline. Comprehensive designs of EH powered transmitters are also discussed, where the EH rate, battery capacity, and deadline requirement can be jointly adjusted to leverage QoS and the cost.Peer reviewe

Eriocitrin alleviates sevoflurane-induced cytotoxicity in HT22 cells via Nrf2 pathway

Purpose: To investigate the effect of eriocitrin on sevoflurane-induced neurotoxicity in mice.Methods: Mouse hippocampal neurons (HT22) were exposed to different concentrations of sevoflurane for 6 h and then incubated with different concentrations of eriocitrin for another 24 h. Cell viability was determined by CCK8 assay, while fluorescence intensity of dichlorodihydrofluorescein was used to evaluate reactive oxygen species. Enzyme linked immunosorbent assay (ELISA) was used to determine oxidative stress, and cellular apoptosis was determined by flow cytometry.Results: Sevoflurane exposure decreased HT22 cell viability, whereas incubation with eriocitrin increased viability of sevoflurane-treated HT22 cells (p < 0.05). Sevoflurane-induced increase in dichlorodihydrofluorescein fluorescence intensity was reduced by eriocitrin, but eriocitrin attenuated sevoflurane-induced increase in malondialdehyde, superoxide dismutase, and glutathione peroxidase in HT22 cells. Cell apoptosis increased after sevoflurane exposure, and eriocitrin suppressed apoptosis in sevoflurane-treated HT22 cells through downregulation of cleaved caspase-3 and cleaved caspase-9 (p< 0.05). Eriocitrin incubation enhanced protein expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NAD(P)H quinone dehydrogenase 1 (NQO1) in sevoflurane-treated HT22 cells (p < 0.05).Conclusion: Eriocitrin ameliorates sevoflurane-induced oxidative stress and inflammatory response in HT22 cells via activation of Nrf2/HO-1/NQO1 signaling. Thus, agent may be useful in the treatment of sevoflurane-induced toxicity, but in vivo studies are required to buttress this

A survey of speech enhancement algorithms

speech is easy to be interfered by the external environment in real applications, resulting in the reduction of speech intelligibility and signal-to-noise ratio. In the past few decades, due to the wide application of speech based solutions in practical applications, speech enhancement of noisy speech signals has aroused considerable research interest. This paper classifi es and introduces several main speech enhancement methods, summarizes the advantages and disadvantages of several main methods, and fi nally puts forward the next research direction of speech enhancement methods

High-Performance Multi-Mode Ptychography Reconstruction on Distributed GPUs

Ptychography is an emerging imaging technique that is able to provide wavelength-limited spatial resolution from specimen with extended lateral dimensions. As a scanning microscopy method, a typical two-dimensional image requires a number of data frames. As a diffraction-based imaging technique, the real-space image has to be recovered through iterative reconstruction algorithms. Due to these two inherent aspects, a ptychographic reconstruction is generally a computation-intensive and time-consuming process, which limits the throughput of this method. We report an accelerated version of the multi-mode difference map algorithm for ptychography reconstruction using multiple distributed GPUs. This approach leverages available scientific computing packages in Python, including mpi4py and PyCUDA, with the core computation functions implemented in CUDA C. We find that interestingly even with MPI collective communications, the weak scaling in the number of GPU nodes can still remain nearly constant. Most importantly, for realistic diffraction measurements, we observe a speedup ranging from a factor of $10$ to $10^3$ depending on the data size, which reduces the reconstruction time remarkably from hours to typically about 1 minute and is thus critical for real-time data processing and visualization.Comment: work presented in NYSDS 201