128 research outputs found
Risk Measures and Their Applications in the Stock Market
We present an overview of various risk measures proposed in literature. Using parametric and non-parametric estimations based on data from Yahoo Finance, we conduct an empirical study comparing the uses of different measurements of risks associated with stock returns across various sectors
Improved Consensus ADMM for Cooperative Motion Planning of Large-Scale Connected Autonomous Vehicles with Limited Communication
This paper investigates a cooperative motion planning problem for large-scale
connected autonomous vehicles (CAVs) under limited communications, which
addresses the challenges of high communication and computing resource
requirements. Our proposed methodology incorporates a parallel optimization
algorithm with improved consensus ADMM considering a more realistic locally
connected topology network, and time complexity of O(N) is achieved by
exploiting the sparsity in the dual update process. To further enhance the
computational efficiency, we employ a lightweight evolution strategy for the
dynamic connectivity graph of CAVs, and each sub-problem split from the
consensus ADMM only requires managing a small group of CAVs. The proposed
method implemented with the receding horizon scheme is validated thoroughly,
and comparisons with existing numerical solvers and approaches demonstrate the
efficiency of our proposed algorithm. Also, simulations on large-scale
cooperative driving tasks involving 80 vehicles are performed in the
high-fidelity CARLA simulator, which highlights the remarkable computational
efficiency, scalability, and effectiveness of our proposed development.
Demonstration videos are available at
https://henryhcliu.github.io/icadmm_cmp_carla.Comment: 15 pages, 10 figure
FS-BAND: A Frequency-Sensitive Banding Detector
Banding artifact, as known as staircase-like contour, is a common quality
annoyance that happens in compression, transmission, etc. scenarios, which
largely affects the user's quality of experience (QoE). The banding distortion
typically appears as relatively small pixel-wise variations in smooth
backgrounds, which is difficult to analyze in the spatial domain but easily
reflected in the frequency domain. In this paper, we thereby study the banding
artifact from the frequency aspect and propose a no-reference banding detection
model to capture and evaluate banding artifacts, called the Frequency-Sensitive
BANding Detector (FS-BAND). The proposed detector is able to generate a
pixel-wise banding map with a perception correlated quality score. Experimental
results show that the proposed FS-BAND method outperforms state-of-the-art
image quality assessment (IQA) approaches with higher accuracy in banding
classification task.Comment: arXiv admin note: substantial text overlap with arXiv:2311.1775
BAND-2k: Banding Artifact Noticeable Database for Banding Detection and Quality Assessment
Banding, also known as staircase-like contours, frequently occurs in flat
areas of images/videos processed by the compression or quantization algorithms.
As undesirable artifacts, banding destroys the original image structure, thus
degrading users' quality of experience (QoE). In this paper, we systematically
investigate the banding image quality assessment (IQA) problem, aiming to
detect the image banding artifacts and evaluate their perceptual visual
quality. Considering that the existing image banding databases only contain
limited content sources and banding generation methods, and lack perceptual
quality labels (i.e. mean opinion scores), we first build the largest banding
IQA database so far, named Banding Artifact Noticeable Database (BAND-2k),
which consists of 2,000 banding images generated by 15 compression and
quantization schemes. A total of 23 workers participated in the subjective IQA
experiment, yielding over 214,000 patch-level banding class labels and 44,371
reliable image-level quality ratings. Subsequently, we develop an effective
no-reference (NR) banding evaluator for banding detection and quality
assessment by leveraging frequency characteristics of banding artifacts. A dual
convolutional neural network is employed to concurrently learn the feature
representation from the high-frequency and low-frequency maps, thereby
enhancing the ability to discern banding artifacts. The quality score of a
banding image is generated by pooling the banding detection maps masked by the
spatial frequency filters. Experiments demonstrate that our banding evaluator
achieves a remarkably high accuracy in banding detection and also exhibits high
SRCC and PLCC results with the perceptual quality labels. These findings unveil
the strong correlations between the intensity of banding artifacts and the
perceptual visual quality, thus validating the necessity of banding quality
assessment
Association of lipoprotein lipase (LPL) gene variants with hyperlipidemic acute pancreatitis in southeastern Chinese population
ABSTRACT Objective: The study aims to explore the relationship between lipoprotein lipase (LPL) variants and hyperlipidemic acute pancreatitis (HLAP) in the southeastern Chinese population. Subjects and methods: In total, 80 participants were involved in this study (54 patients with HLAP and 26 controls). All coding regions and intron-exon boundaries of the LPL gene were sequenced. The correlations between variants and phenotypes were also analysed. Results: The rate of rare LPL variants in the HLAP group is 14.81% (8 of 54), higher than in controls. Among the detected four variants (rs3735959, rs371282890, rs761886494 and rs761265900), the most common variant was rs371282890. Further analysis demonstrated that subjects with rs371282890 "GC" genotype had a 2.843-fold higher risk for HLAP (odds ratio [OR]: 2.843, 95% confidence interval [CI]: 1.119-7.225, p = 0.028) than subjects with the "CC" genotype. After adjusting for sex, the association remained significant (adjusted OR: 3.083, 95% CI: 1.208-7.869, p = 0.018). Subjects with rs371282890 "GC" genotype also exhibited significantly elevated total cholesterol, triglyceride and non-high-density lipoprotein cholesterol levels in all the participants and the HLAP group (p < 0.05). Conclusion: Detecting rare variants in LPL might be valuable for identifying higher-risk patients with HLAP and guiding future individualised therapeutic strategies
Kagome surface states and weak electronic correlation in vanadium-kagome metals
RV6Sn6 (R = Y and lanthanides) with two-dimensional vanadium-kagome surface
states is an ideal platform to investigate kagome physics and manipulate the
kagome features to realize novel phenomena. Utilizing the micron-scale
spatially resolved angle-resolved photoemission spectroscopy and
first-principles calculations, we report a systematical study of the electronic
structures of RV6Sn6 (R = Gd, Tb, and Lu) on the two cleaved surfaces, i.e.,
the V- and RSn1-terminated (001) surfaces. The calculated bands without any
renormalization match well with the main ARPES dispersive features, indicating
the weak electronic correlation in this system. We observe 'W'-like kagome
surface states around the Brillouin zone corners showing R-element-dependent
intensities, which is probably due to various coupling strengths between V and
RSn1 layers. Our finding suggests an avenue for tuning electronic states by
interlayer coupling based on two-dimensional kagome lattices
Multimodal multiphoton imaging for label-free monitoring of early gastric cancer
Background
Early gastric cancer is associated with a much better prognosis than advanced disease, and strategies to improve prognosis is strictly dependent on earlier detection and accurate diagnosis. Therefore, a label-free, non-invasive imaging technique that allows the precise identification of morphologic changes in early gastric cancer would be of considerable clinical interest.
Methods
In this study, multiphoton microscopy (MPM) using two-photon excited fluorescence combined with second-harmonic generation was used for the identification of early gastric cancer.
Results
This microscope was able to directly reveal improved cellular detail and stromal changes during the development of early gastric cancer. Furthermore, two features were quantified from MPM images to assess the cell change in size and stromal collagen change as gastric lesion developed from normal to early cancer.
Conclusions
These results clearly show that multiphoton microscopy can be used to examine early gastric cancer at the cellular level without the need for exogenous contrast agents. This study would be helpful for early diagnosis and treatment of gastric cancer, and may provide the groundwork for further exploration into the application of multiphoton microscopy in clinical practice.Ope
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