Towards Accurate One-Stage Object Detection with AP-Loss

One-stage object detectors are trained by optimizing classification-loss and localization-loss simultaneously, with the former suffering much from extreme foreground-background class imbalance issue due to the large number of anchors. This paper alleviates this issue by proposing a novel framework to replace the classification task in one-stage detectors with a ranking task, and adopting the Average-Precision loss (AP-loss) for the ranking problem. Due to its non-differentiability and non-convexity, the AP-loss cannot be optimized directly. For this purpose, we develop a novel optimization algorithm, which seamlessly combines the error-driven update scheme in perceptron learning and backpropagation algorithm in deep networks. We verify good convergence property of the proposed algorithm theoretically and empirically. Experimental results demonstrate notable performance improvement in state-of-the-art one-stage detectors based on AP-loss over different kinds of classification-losses on various benchmarks, without changing the network architectures. Code is available at https://github.com/cccorn/AP-loss.Comment: 13 pages, 7 figures, 4 tables, main paper + supplementary material, accepted to CVPR 201

Gradual Enhancement of Stripe-Type Antiferromagnetism in Spin Ladder Material BaFe2_2S3_3 Under Pressure

We report pressure-dependent neutron diffraction and muon spin relaxation/rotation measurements combined with first-principles calculations to investigate the structural, magnetic, and electronic properties of BaFe$_2$S$_3$ under pressure. The experimental results reveal a gradual enhancement of the stripe-type ordering temperature with increasing pressure up to 2.6 GPa and no observable change in the size of the ordered moment. The ab initio calculations suggest that the magnetism is highly sensitive to the Fe-S bond lengths and angles, clarifying discrepancies with previously published results. In contrast to our experimental observations, the calculations predict a monotonic reduction of the ordered moment with pressure. We suggest that the robustness of the stripe-type antiferromagnetism is due to strong electron correlations not fully considered in the calculations

Dry mass input into fruits can be predicted by fine root morphology of pepper cultivars exposed to varied lighting spectra

Many pepper cultivars can be raised under artificial lighting in a plant factory. An easily measured parameter is needed to fast predict fruit loading in pepper cultivars. In this study, four pepper cultivars with contrasting manners in growth and fruiting were cultured under three light-emitting diode (LED) spectra in comparison with a sunlight control. It was found that the red-light spectrum (71.7% red-, 13.7% green-, 14.6% blue-lights) increased over 40% of dry mass in fruits, while the green-light spectrum (26.2% red-, 56.4% green-, 17.4% blue-lights) induced no fruiting compared to the control. Only two cultivars responded by fine root morphology, which was characterized as smaller surface-area and fewer tip-number in the blue-light spectrum (7.8% red-, 33.7% green-, 48.5% blue-lights) than in red LED light. Tip-number showed a negative correlation with fruit dry-mass in three cultivars, while fine root diameter increased with dry mass in fruits. In conclusion, fine root tip-number can be used as a predictor of fruit dry-mass in pepper cultivars high in fruit quality or yield. The red-colour light was recommended for raising pepper cultivars in a plant factory with the purpose of greater fruit productivity

Synthesis of SB-T-12301 Analogues and Tumor-Targeting Taxane-Based Drug Conjugates using Biotin as Tumor-Targeting Module

Cancer is one of the most serious diseases of the world, leading to one of eight deaths. Although the medical advancements have contributed greatly to the decline of other diseases, treatments for cancer have remained only modestly effective. Traditional chemotherapeutics such as Taxol and Taxotere generally lack specificity, and repeated administration often leads to multi-drug resistance (MDR). To increase the efficacy and specificity of drugs, both the synthesis and evaluation of lead compounds and the development of drug delivery system are equally important. SB-T-1214 and three novel taxanes, SB-T-12301 and two of its analogues, were synthesized by the standard Ojima-Holton coupling protocol using the corresponding β -lactam and 7,10-dimethylated-10-DAB III and C-2 meta-methyl or fluorobenzoyl 7,10-dimethylated-10-DAB III. The β -lactam was obtained via two well-established synthetic routes: Staudinger [2+2] cycloaddition followed by enzymatic resolution protocol and the chiral ester enolate-imine cyclocondensation. In addition, tumor-targeting taxane-based drug conjugate was synthesized by using biotin as the tumor-targeting module and a self-immolative disulfide linker, which can be cleaved in cancer cells due to high concentration of glutathione. Biotin plays a critical role in many biological processes. It is greedily taken up by tumor cells through a process of receptor-mediated endocytosis (RME) to meet its need of fast growth and propagation. The receptors of biotin are highly overexpressed on the surface of tumor cells and making them a good target for tumor-targeting drug design. | 169 page

Repeated Loading Model for Elastic-Plastic Contact of Geomaterial

A new nonlinear hysteretic model with considering the loading, unloading, and reloading processes is developed based on Drucker—Prager yield criterion and finite-element analysis. This model can be used for multiple repeated elastic—plastic normal direction contact problems between two identical spherical geomaterials. After examining the influence of material properties, strain hardening, and loading histories, we found that the hysteretic phenomena (represented by residual displacement and plastic work) become weak after the first cycle, and the subsequent cycles step into elastic shakedown state eventually. A critical number of cycles can be used to estimate the state of ratchetting, plastic shakedown, as well as elastic shakedown. It also found that the subsequent curves will be stiffer than the previous ones, especially when the yield strength is high and ratchetting effect is not strong. This new model can be used for a wide range of geomaterials under different loading levels, and it can also be extended to describe the constitutive behavior of spheres under earthquake as well as aftershocks

Multi-ancestry study of blood lipid levels identifies four loci interacting with physical activity.

Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol-increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels

A novel gas ionization sensor using Pd nanoparticle-capped ZnO

A novel gas ionization sensor using Pd nanoparticle-capped ZnO (Pd/ZnO) nanorods as the anode is proposed. The Pd/ZnO nanorod-based sensors, compared with the bare ZnO nanorod, show lower breakdown voltage for the detected gases with good sensitivity and selectivity. Moreover, the sensors exhibit stable performance after more than 200 tests for both inert and active gases. The simple, low-cost, Pd/ZnO nanorod-based field-ionization gas sensors presented in this study have potential applications in the field of gas sensor devices

Study on the airworthiness certification technical system and key contents of aircraft tire burst

The research on aircraft tire blasting approval technology is of great significance to promote aircraft forensics and improve aircraft safety. In order to further promote the development of tire burst airworthiness technology and standardize the technical system, the development status and differences of applicable tire burst airworthiness regulations in various countries are tracked and investigated. Based on the engineering practice of domestic civil aircraft on the latest international tire burst airworthiness certification, an airworthiness certification technology system for aviation tire explosions in accordance with clause CS 25.734 is established, the verification process, verification objects, related clauses, and certification technical indicators are refined, and the expected safety level of CS 25.734 is fully interpreted. The key elements and suggestions for airworthiness certification that require special attention are proposed. The results show that the newly revised proprietary clause CS 25.734 of the EASA requires higher requirements and clearer tire burst modes. The airworthiness certification technology system, certification elements, and recommendations for aviation tire explosions mentioned in this article are validated in the airworthiness certification of a domestic large passenger aircraft, which can provide guidance for industry reviewers and designers, and is a new breakthrough in the field of certification technology in China

Emergency Resource Layout with Multiple Objectives under Complex Disaster Scenarios

Effective placement of emergency rescue resources, particularly with joint suppliers in complex disaster scenarios, is crucial for ensuring the reliability, efficiency, and quality of emergency rescue activities. However, limited research has considered the interaction between different disasters and material classification, which are highly vital to the emergency rescue. This study provides a novel and practical framework for reliable strategies of emergency rescue under complex disaster scenarios. The study employs a scenario-based approach to represent complex disasters, such as earthquakes, mudslides, floods, and their interactions. In optimizing the placement of emergency resources, the study considers government-owned suppliers, framework agreement suppliers, and existing suppliers collectively supporting emergency rescue materials. To determine the selection of joint suppliers and their corresponding optimal material quantities under complex disaster scenarios, the research proposes a multi-objective model that integrates cost, fairness, emergency efficiency, and uncertainty into a facility location problem. Finally, the study develops an NSGA-II-XGB algorithm to solve a disaster-prone province example and verify the feasibility and effectiveness of the proposed multi-objective model and solution methods. The results show that the methodology proposed in this paper can greatly reduce emergency costs, rescue time, and the difference between demand and suppliers while maximizing the coverage of rescue resources. More importantly, it can optimize the scale of resources by determining the location and number of materials provided by joint suppliers for various kinds of disasters simultaneously. This research represents a promising step towards making informed configuration decisions in emergency rescue work