172 research outputs found
Unipolar Resistance Switching in Amorphous High-k dielectrics Based on Correlated Barrier Hopping Theory
We have proposed a kind of nonvolatile resistive switching memory based on
amorphous LaLuO3, which has already been established as a promising candidate
of high-k gate dielectric employed in transistors. Well-developed unipolar
switching behaviors in amorphous LaLuO3 make it suited for not only logic but
memory applications using the conventional semiconductor or the emerging
nano/CMOS architectures. The conduction transition between high- and low-
resistance states is attributed to the change in the separation between oxygen
vacancy sites in the light of the correlated barrier hopping theory. The mean
migration distances of vacancies responsible for the resistive switching are
demonstrated in nanoscale, which could account for the ultrafast programming
speed of 6 ns. The origin of the distributions in switching parameters in
oxides can be well understood according to the switching principle.
Furthermore, an approach has also been developed to make the operation voltages
predictable for the practical applications of resistive memories.Comment: 18 pages, 6 figure
NIPD: A Federated Learning Person Detection Benchmark Based on Real-World Non-IID Data
Federated learning (FL), a privacy-preserving distributed machine learning,
has been rapidly applied in wireless communication networks. FL enables
Internet of Things (IoT) clients to obtain well-trained models while preventing
privacy leakage. Person detection can be deployed on edge devices with limited
computing power if combined with FL to process the video data directly at the
edge. However, due to the different hardware and deployment scenarios of
different cameras, the data collected by the camera present non-independent and
identically distributed (non-IID), and the global model derived from FL
aggregation is less effective. Meanwhile, existing research lacks public data
set for real-world FL object detection, which is not conducive to studying the
non-IID problem on IoT cameras. Therefore, we open source a non-IID IoT person
detection (NIPD) data set, which is collected from five different cameras. To
our knowledge, this is the first true device-based non-IID person detection
data set. Based on this data set, we explain how to establish a FL experimental
platform and provide a benchmark for non-IID person detection. NIPD is expected
to promote the application of FL and the security of smart city.Comment: 8 pages, 5 figures, 3 tables, FL-IJCAI 23 conferenc
Design of the offline test electronics for the nozzle system of proton therapy
A set of nozzle equipment for proton therapy is now being developed at China
Institute of Atomic Energy. To facilitate the off-line commissioning of the
whole equipment, a set of ionization chamber signal generation system, the test
electronics, is designed. The system uses ZYNQ SoC as the main control unit and
outputs the beam dose analog signal through DAC8532. The dual SPDT analog
switch, DG636, is used to simulate the beam position signals according to
Gaussian distribution. The results show that the system can simulate the beam
position, dose, and other related analog signals generated by the proton beam
when passing through the ionization chamber. Moreover, the accuracy of the
simulated beam position is within +/-0.33mm, and the accuracy of the simulated
dose signal is within +/-1%. At the same time, it can output analog signals
representing environmental parameters. The test electronics meets the design
requirements, which can be used to commission the nozzle system as well as the
treatment control system without the proton beam
Phylogenetic studies of magnoliids: Advances and perspectives
Magnoliids are the largest flowering plant clades outside of the eudicots and monocots, which are distributed worldwide and have high economic, ornamental and ecological values. Eudicots, monocots and magnoliids are the three major clades of Mesangiospermae, and their phylogenetic relationship is one of the most interesting issues. In recent years, with the continuous accumulation of genomic information, the evolutionary status of magnoliids has become a hot spot in plant phylogenetic research. Although great efforts have been made to study the evolution of magnoliids using molecular data from several representative species such as nuclear genome, plastid genome, mitochondrial genome, and transcriptome, the results of current studies on the phylogenetic status of magnoliids are inconsistent. Here, we systematically describe the current understanding of the molecular research on magnoliid phylogeny and review the differences in the evolutionary state of magnoliids. Understanding the research approaches and limitations of magnoliid phylogeny can guide research strategies to further improve the study of the phylogenetic evolution of magnoliids
A Ferroelectric Compute-in-Memory Annealer for Combinatorial Optimization Problems
Computationally hard combinatorial optimization problems (COPs) are
ubiquitous in many applications, including logistical planning, resource
allocation, chip design, drug explorations, and more. Due to their critical
significance and the inability of conventional hardware in efficiently handling
scaled COPs, there is a growing interest in developing computing hardware
tailored specifically for COPs, including digital annealers, dynamical Ising
machines, and quantum/photonic systems. However, significant hurdles still
remain, such as the memory access issue, the system scalability and restricted
applicability to certain types of COPs, and VLSI-incompatibility, respectively.
Here, a ferroelectric field effect transistor (FeFET) based compute-in-memory
(CiM) annealer is proposed. After converting COPs into quadratic unconstrained
binary optimization (QUBO) formulations, a hardware-algorithm co-design is
conducted, yielding an energy-efficient, versatile, and scalable hardware for
COPs. To accelerate the core vector-matrix-vector (VMV) multiplication of QUBO
formulations, a FeFET based CiM array is exploited, which can accelerate the
intended operation in-situ due to its unique three-terminal structure. In
particular, a lossless compression technique is proposed to prune typically
sparse QUBO matrix to reduce hardware cost. Furthermore, a multi-epoch
simulated annealing (MESA) algorithm is proposed to replace conventional
simulated annealing for its faster convergence and better solution quality. The
effectiveness of the proposed techniques is validated through the utilization
of developed chip prototypes for successfully solving graph coloring problem,
indicating great promise of FeFET CiM annealer in solving general COPs.Comment: 39 pages, 12 figure
Rif1 Maintains Telomere Length Homeostasis of ESCs by Mediating Heterochromatin Silencing
SummaryTelomere length homeostasis is essential for genomic stability and unlimited self-renewal of embryonic stem cells (ESCs). We show that telomere-associated protein Rif1 is required to maintain telomere length homeostasis by negatively regulating Zscan4 expression, a critical factor for telomere elongation by recombination. Depletion of Rif1 results in terminal hyperrecombination, telomere length heterogeneity, and chromosomal fusions. Reduction of Zscan4 by shRNA significantly rescues telomere recombination defects of Rif1-depleted ESCs and associated embryonic lethality. Further, Rif1 negatively modulates Zscan4 expression by maintaining H3K9me3 levels at subtelomeric regions. Mechanistically, Rif1 interacts and stabilizes H3K9 methylation complex. Thus, Rif1 regulates telomere length homeostasis of ESCs by mediating heterochromatic silencing
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