9,426 research outputs found
Mean Square Capacity of Power Constrained Fading Channels with Causal Encoders and Decoders
This paper is concerned with the mean square stabilization problem of
discrete-time LTI systems over a power constrained fading channel. Different
from existing research works, the channel considered in this paper suffers from
both fading and additive noises. We allow any form of causal channel
encoders/decoders, unlike linear encoders/decoders commonly studied in the
literature. Sufficient conditions and necessary conditions for the mean square
stabilizability are given in terms of channel parameters such as transmission
power and fading and additive noise statistics in relation to the unstable
eigenvalues of the open-loop system matrix. The corresponding mean square
capacity of the power constrained fading channel under causal encoders/decoders
is given. It is proved that this mean square capacity is smaller than the
corresponding Shannon channel capacity. In the end, numerical examples are
presented, which demonstrate that the causal encoders/decoders render less
restrictive stabilizability conditions than those under linear
encoders/decoders studied in the existing works.Comment: Accepted by the 54th IEEE Conference on Decision and Contro
Molecular characterization and function analysis of the vitellogenin receptor from the cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera, Noctuidae)
Developing oocytes accumulate plentiful yolk protein during oogenesis through receptor-mediated endocytosis. The vitellogenin receptor (VgR), belonging to the low-density lipoprotein receptor (LDLR) family, regulates the absorption of yolk protein. In this work, the full-length vitellogenin receptor (HaVgR) in the cotton bollworm Helicoverpa armigera was identified, encoding a 1817 residue protein. Sequence alignment revealed that the sequence of HaVgR contained all of the conservative structural motifs of LDLR family members, and phylogenetic analysis indicated that HaVgR had a high identity among Lepidoptera and was distinct from that of other insects. Consistent with other insects, HaVgR was specifically expressed in ovarian tissue. The developmental expression pattern showed that HaVgR was first transcribed in the newly metamorphosed female adults, reached a peak in 2-day-old adults and then declined. Western blot analysis also revealed an ovarian-specific and developing expression pattern, which was consistent with the HaVgR mRNA transcription. Moreover, RNAi-mediated HaVgR knockdown strongly reduced the VgR expression in both the mRNA and protein levels, which inhibited the yolk protein deposition in the ovaries, led to the dramatic accumulation of vitellogenin and the up-regulation of HaVg expression in hemolymph, and eventually resulted in a declined fecundity. Together, all of these findings demonstrate that HaVgR is a specific receptor in uptake and transportation of yolk protein for the maturation of oocytes and that it plays a critical role in female reproduction
Joint state of charge and state of health estimation of lithium-ion battery using improved adaptive dual extended Kalman filter based on piecewise forgetting factor recursive least squares.
This work aims to improve the accuracy of state of charge estimation for lithium-ion battery, as well as to accurately estimate state of health. This study presents a piecewise forgetting factor recursive least squares method based on integral separation with a second-order resistor-capacitor model and uses a novel adaptive filter based on error covariance correction on the conventional dual extended Kalman filter. The experiments show that the error of SOC estimation is less than 0.61% and the error of SOH is less than 0.09% under different complex conditions, the proposed method can effectively improve the estimation accuracy and robustness
Molecular cloning and characterization of a chitinase gene up-regulated in longan buds during flowering reversion
A cDNA-amplified fragment length polymorphism (cDNA-AFLP) technique was used for differential screening of genes expressed in longan (Dimocarpus longan Lour.) flower buds undergoing normal development versus flowering reversion. One cDNA fragment up-regulated during flowering reversion was further cloned by rapid amplification of cDNA ends (RACE) technology. This cDNA consists of 961 nucleotides and encodes an open reading frame (ORF) of 227-amino acid residues. The nucleotides and deduced amino acid sequence were both identical against published chitinases from other species and hence this cDNA was designated as DLchi (GenBank accession No. GU177464). It has a signal peptide and glycoside hydrolase’s domain. The estimated molecular weight was 24.77 kD and the isoelectric point was 5.17. This protein might be grouped as a new member of class II chitinase based on the sequences available and hypothesis discussed. DLchi might be involved in the flower bud abscission observed in longan flowering reversion.Key words: Longan, flowering reversion, chitinase gene, cloning, sequence analysis
CASOG: Conservative Actor-critic with SmOoth Gradient for Skill Learning in Robot-Assisted Intervention
Robot-assisted intervention has shown reduced radiation exposure to
physicians and improved precision in clinical trials. However, existing
vascular robotic systems follow master-slave control mode and entirely rely on
manual commands. This paper proposes a novel offline reinforcement learning
algorithm, Conservative Actor-critic with SmOoth Gradient (CASOG), to learn
manipulation skills from human demonstrations on vascular robotic systems. The
proposed algorithm conservatively estimates Q-function and smooths gradients of
convolution layers to deal with distribution shift and overfitting issues.
Furthermore, to focus on complex manipulations, transitions with larger
temporal-difference error are sampled with higher probability. Comparative
experiments in a pre-clinical environment demonstrate that CASOG can deliver
guidewire to the target at a success rate of 94.00\% and mean backward steps of
14.07, performing closer to humans and better than prior offline reinforcement
learning methods. These results indicate that the proposed algorithm is
promising to improve the autonomy of vascular robotic systems.Comment: 13 pages, 5 figure, preprin
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