ConjNorm: Tractable Density Estimation for Out-of-Distribution Detection

Post-hoc out-of-distribution (OOD) detection has garnered intensive attention in reliable machine learning. Many efforts have been dedicated to deriving score functions based on logits, distances, or rigorous data distribution assumptions to identify low-scoring OOD samples. Nevertheless, these estimate scores may fail to accurately reflect the true data density or impose impractical constraints. To provide a unified perspective on density-based score design, we propose a novel theoretical framework grounded in Bregman divergence, which extends distribution considerations to encompass an exponential family of distributions. Leveraging the conjugation constraint revealed in our theorem, we introduce a \textsc{ConjNorm} method, reframing density function design as a search for the optimal norm coefficient $p$ against the given dataset. In light of the computational challenges of normalization, we devise an unbiased and analytically tractable estimator of the partition function using the Monte Carlo-based importance sampling technique. Extensive experiments across OOD detection benchmarks empirically demonstrate that our proposed \textsc{ConjNorm} has established a new state-of-the-art in a variety of OOD detection setups, outperforming the current best method by up to 13.25$\%$ and 28.19$\%$ (FPR95) on CIFAR-100 and ImageNet-1K, respectively.Comment: ICLR24 poste

Linear-Model-inspired Neural Network for Electromagnetic Inverse Scattering

Electromagnetic inverse scattering problems (ISPs) aim to retrieve permittivities of dielectric scatterers from the scattering measurement. It is often highly nonlinear, caus-ing the problem to be very difficult to solve. To alleviate the issue, this letter exploits a linear model-based network (LMN) learning strategy, which benefits from both model complexity and data learning. By introducing a linear model for ISPs, a new model with network-driven regular-izer is proposed. For attaining efficient end-to-end learning, the network architecture and hyper-parameter estimation are presented. Experimental results validate its superiority to some state-of-the-arts.Comment: 5 pages, 6 figures 3 table

A Novel Compact Dual-Polarized Antenna

A novel compact dual-polarized antenna is proposed. The antenna has a 1.43% impedance bandwidth which is from 1801 MHz to 1827 MHz for return loss larger than 10 dB. The isolation between the two ports is above 28 dB in the bandwidth, and the gain is 6.6 dBi. The proposed antenna not only consists of a full-planar structure, but also is easy to be fabricated for its simple structure. Additionally, a section of slots and slits is cut on the radiation patch to reduce the area of it to 54% compared with the conventional square patch

Formation of Fan-spine Magnetic Topology through Flux Emergence and Subsequent Jet Production

Fan-spine magnetic structure, as a fundamental three-dimensional topology in magnetic reconnection theory, plays a crucial role in producing solar jets. However, how fan-spine configurations form in the solar atmosphere remains elusive. Using the Chinese H$\alpha$ Solar Explorer (CHASE) and the Solar Dynamics Observatory (SDO), we present a case study on the complete buildup of fan-spine topology driven by flux emergence and the subsequent jet production. Two fan-spine structures and the two associated null points are present. Variations in null-point heights and locations were tracked over time during flux emergence. The north fan-spine structure is found to be created through magnetic reconnection between the newly emerged flux and the background field. Gentle reconnection persistently occurs after formation of the north fan-spine structure, resulting in weak plasma outflows. Subsequently, as flux emergence and magnetic helicity injection continue, the formation and eruption of mini-filaments after reconnection at the quasi-separatrix layer between the two nulls trigger three homologous jets. The CHASE observations reveal that the circular flare ribbon, inner bright patch, and remote brightening all exhibit redshifted signatures during these jet ejections. This work unveils the key role of flux emergence in the formation of fan-spine topology, and highlights the importance of mini-filaments for subsequent jet production.Comment: 20 pages, 7 figures accepted by the ApJ

Antioxidants and Antioxidant Capacity in Leafy, Stem, and Fruit Vegetables Including 50 Species

Epidemiological studies have confirmed that high intake of fruits and vegetables is associated with low incidence of many kinds of diseases, which are hypothesized to be owing to antioxidants in fruits and vegetables. In this study, three types (leafy, stem, fruit) vegetables including 50 species were systematically evaluated for their antioxidant capacity (AC) and antioxidants including total phenolic compound (TPC), total flavonoids (TF), and L-ascorbic acid (LAA). Results showed that vegetables types had no significant effects on antioxidants. Vegetables with vivid color like purple cabbage, purple dolichos lablab, purple cowpea, red pepper, yellow pepper, lotus root, and ginger ranked high in their antioxidants (TPC 32.76-117.63 mg gallic acid/g FW, TF 25.78-152.96 mg rutin/100g FW, LAA 69.11-165.44 mg/100g FW) and AC (FRAP 69.38-109.13 μmol Fe2+/100gFW, ABTS 2.19-3.75 μmol Trolox/gFW). Relatively, crown daisy, endive, celery stem, and cucumber had low antioxidants (TPC 2.66-6.29 mg gallic acid/g FW, TF 10.37-37.56 mg rutin/100g FW, LAA 14.64-39.44 mg/100g FW) and AC (FRAP 1.99-10.81 μmol Fe2+/100gFW, ABTS 0.39-0.68 μmol Trolox/gFW). TPC and LAA had strong positive correlations with AC regardless of vegetable types, while TF was positively related to AC only in leafy vegetables. The result would be valuable for both epidemiological research and dietary guidelines as these vegetables are affordable and widely available