Joint attribute chain prediction for zero‐shot learning

Zero‐shot learning (ZSL) aims to classify the objects without any training samples. Attributes are used to transfer knowledge from the training set to testing one in ZSL. Most ZSL methods based on Direct Attribute Prediction (DAP) assume that attributes are independent of each other. In this study, the authors explore the relationship between attributes and propose Joint Attribute Chain Prediction (JACP). Attribute chains are introduced to represent the relations. Conditional probabilities of attributes are estimated orderly along the chain to calculate the joint posteriors of the testing classes without independence assumptions. To reduce the estimation error, attribute relation clustering algorithm is presented to group the long chain into some unrelated small chains. When the max length of chains is one, JACP is essentially identical with DAP. Experiments on three data sets for zero‐shot problem demonstrate the classification accuracy and efficiency of the authors’ algorithm. The results show that mining attribute relations can greatly improve the performance of ZSL effectively

Prediction of High-Cycle Fatigue Performance of 1Cr11Ni2W2MoV Stainless Steel Plate after Foreign Object Damage

High-cycle fatigue (HCF) properties of 1Cr11Ni2W2MoV stainless steel impacted by a high-speed steel ball were studied by the foreign object damage (FOD) test and HCF test. The results show that the damage depth Z has the most obvious effect on the HCF limit of notched flat plate specimens, and the fatigue limit decreases with the increase of depth Z. The microcharacteristics of the FOD notch and HCF fracture of 1Cr11Ni2W2MoV stainless steel were observed by a scanning electron microscope (SEM). The results show that the microdamage features such as plastic deformation, loss of material, and microcracks promote the initiation and propagation of fatigue cracks, and the fatigue source area lies near the root of the notch. The Peterson formula and Worst Case Notch (WCN) mode were used to predict the HCF limit of flat plate specimens after FOD. The crack growth threshold was obtained by the crack growth test. The results show that the prediction results of both methods are conservative. For the notch with damage depth Z1 mm, the prediction results of both methods have large errors (>30%) with the WCN model being slightly more accurate

Effects of Landscape Attributes on Campuses Bird Species Richness and Diversity, Implications for Eco-Friendly Urban Planning

Landscape changes due to urban expansion may severely influence urban biodiversity through direct and indirect effects. Hence, a comprehensive understanding of the urban expansion effects on species diversity is essential for conservation biologists, urban planners, and policymakers to help design more practical and effective conservation strategies. Here, based on monthly bird survey data of 12 university campuses distributed in the center and the Xianlin university town of Nanjing city, we first compared the differences of the campuses bird species richness, Shannon-Wiener, and Simpson indices. Then, we analyzed the effects of a variety of landscape attributes on the campuses bird species richness. Unlike other studies, we also constructed a 2 km buffer area surrounding each campus and analyzed the effects of the landscape attributes of the buffer area on species richness. We found that bird species richness was higher in the campus of Xianlin compared to those in the center. Landscape attributes played an important role on bird species richness, especially for the determinants in the buffer area. Specifically, species richness, Shannon-Wiener, and Simpson indices increased with the increasing area of water and green space both within the campus and the buffer area. Not surprisingly, bird species richness and diversity were more affected by fragmentation of the buffer area, increasing with the aggregation index and decreasing with the splitting index. Our study emphasized that landscape attributes of both campuses and buffer areas determined bird species richness and diversity, offering several practical implications for urban biodiversity maintenance and eco-friendly urban planning

Experimental study and safety analysis on the heating surfaces in the 660 MW supercritical CFB boiler under sudden electricity failure

Abstract The necessity of equipping with an emergency water supply system in a supercritical circulating fluidized bed (CFB) boiler has long been a controversial topic in the industry. In this study, the heating surface of a 660 MW supercritical CFB boiler at the Pingshuo Power Station of China Coal Group is taken as the research object. And a boiler electricity failure experiment was accomplished at the power plant, and the variations of thermal parameters during electricity failure were obtained from power plant distributed control system. By analyzing the physical process of the heating surfaces during electricity failure, a mathematical model of heat transfer to the heating surface was established and a calculation program in Fortran language was developed. In this study, the effect of different flow rates and operating times of the supply pumps on the safety of the heating surfaces were then investigated. The numerical simulation results show that an emergency supply pump with a flow rate of 250 t/h, activated within 120 s, ensures the safety of the heating surface. The results of this study have important implications for the selection of emergency supply pumps and the determination of flow rates and pressures for supercritical CFB boilers with external beds

Realistic Safety-critical Scenarios Search for Autonomous Driving System via Behavior Tree

The simulation-based testing of Autonomous Driving Systems (ADSs) has gained significant attention. However, current approaches often fall short of accurately assessing ADSs for two reasons: over-reliance on expert knowledge and the utilization of simplistic evaluation metrics. That leads to discrepancies between simulated scenarios and naturalistic driving environments. To address this, we propose the Matrix-Fuzzer, a behavior tree-based testing framework, to automatically generate realistic safety-critical test scenarios. Our approach involves the $log2BT$ method, which abstracts logged road-users' trajectories to behavior sequences. Furthermore, we vary the properties of behaviors from real-world driving distributions and then use an adaptive algorithm to explore the input space. Meanwhile, we design a general evaluation engine that guides the algorithm toward critical areas, thus reducing the generation of invalid scenarios. Our approach is demonstrated in our Matrix Simulator. The experimental results show that: (1) Our $log2BT$ achieves satisfactory trajectory reconstructions. (2) Our approach is able to find the most types of safety-critical scenarios, but only generating around 30% of the total scenarios compared with the baseline algorithm. Specifically, it improves the ratio of the critical violations to total scenarios and the ratio of the types to total scenarios by at least 10x and 5x, respectively, while reducing the ratio of the invalid scenarios to total scenarios by at least 58% in two case studies

The electromechanical features of LiNbO3 crystal for potential high temperature piezoelectric applications

Lithium niobate (LiNbO3, LN) crystal is a multi-functional material with favorable piezoelectric, nonlinear optical and electro-optic properties. In this study, the electromechanical properties of the radial extensional (RE) and the thickness extensional (TE) modes of the congruent LN are studied and the temperature dependent behaviors are revealed. The RE mode electromechanical coupling factors (kp) for the Y- and Z-oriented discs are calculated and found to be 3.8% and 24.7%, respectively, which are nearly the same as the experimental results of 3.8% and 25.2%, respectively. The maximum RE and thickness shear (TS) modes electromechanical coupling factors are obtained to be 47.6% and 68.5% for the Yx/25° and Yx/167° crystal cuts, respectively. The LN crystal possesses good temperature stability of the electromechanical coupling factors (RE and TE modes) from 20 °C to 500 °C, where the variations of kp and kt for the Y-oriented discs are < 8.0% and <1.8%, respectively. Keywords: LiNbO3, Radial extensional mode, Thickness extensional mode, Temperature stabilit

Enhanced Stability and Mobility of Solution-Processed Oxide Thin-Film Transistors with Bilayer Terbium-incorporated Indium Oxide Channel

The trade-off between mobility and stability in oxide thin-film transistors (TFTs) hinders further advances of active-matrix flat panel display. Herein, a solution-processed bilayer active channel is designed to improve the stability and mobility simultaneously. The optical bandgap and work function of Tb:In2O3 films are modulated by tuning the films thickness and Tb concentration of Tb-doped indium oxide (Tb:In2O3) films. Large conduction band offset is achieved in Tb:In2O3 bilayer channel, which induces accumulation of abundant electrons at the interface. The mobility is significantly improved to 38.2 cm2/Vs, and the photoinduced stability of bilayer Tb:In2O3 TFTs is improved with low threshold voltage shift of 0.26 V and −0.38 V under negative-bias illumination stress (NBIS) and negative-bias temperature illumination stress (NBTIS), respectively

Halide-chalcogenide hetero-structure for efficient and stable perovskite solar cells

Organic-inorganic halide perovskite solar cells (PSCs) have experienced rapid growth in power conversion ef-ficiencies (PCEs), however, their commercialization is limited by their inherent poor long-term stability. Mixed halide and chalcogenide is a good pathway to fabricate highly efficient and stable solar cells. Here, we con-structed halide-chalcogenide hetero-structure in PSCs by incorporating Bi2S3 quantum dots (QDs) into 2,2 &apos;,7,7 &apos;- tetrakis-(N,N-di-4-methoxyphenylamino)-9,9 &apos;-spirobifluorene (spiro-OMeTAD). The construction of halide-chalcogenide hetero-structure optimizes the energy level matching between spiro-OMeTAD and perovskite, in-hibits the decomposition of alpha-phase FAPbI3 and the formation of delta-phase FAPbI3, increases the hole mobility of spiro-OMeTAD, reduces the defect density, and passivates the defect states. The solar cells with halide-chalcogenide hetero-structure prepared by 0.5 mg/mL Bi2S3 QDs exhibited the highest PCE of 23.31% at stan-dard air mass 1.5 global with enhanced humidity stability. This work provides a perspective on the introduction of halide-chalcogenide hetero-structure to enhance the stability of PSCs