Study of object recognition and identification based on shape and texture analysis

The objective of object recognition is to enable computers to recognize image patterns without human intervention. According to its applications, it is mainly divided into two parts: recognition of object categories and detection/identification of objects. My thesis studied the techniques of object feature analysis and identification strategies, which solve the object recognition problem by employing effective and perceptually important object features. The shape information is of particular interest and a review of the shape representation and description is presented, as well as the latest research work on object recognition. In the second chapter of the thesis, a novel content-based approach is proposed for efficient shape classification and retrieval of 2D objects. Two object detection approaches, which are designed according to the characteristics of the shape context and SIFT descriptors, respectively, are analyzed and compared. It is found that the identification strategy constructed on a single type of object feature is only able to recognize the target object under specific conditions which the identifier is adapted to. These identifiers are usually designed to detect the target objects which are rich in the feature type captured by the identifier. In addition, this type of feature often distinguishes the target object from the complex scene. To overcome this constraint, a novel prototyped-based object identification method is presented to detect the target object in the complex scene by employing different types of descriptors to capture the heterogeneous features. All types of descriptors are modified to meet the requirement of the detection strategy’s framework. Thus this new method is able to describe and identify various kinds of objects whose dominant features are quite different. The identification system employs the cosine similarity to evaluate the resemblance between the prototype image and image windows on the complex scene. Then a ‘resemblance map’ is established with values on each patch representing the likelihood of the target object’s presence. The simulation approved that this novel object detection strategy is efficient, robust and of scale and rotation invariance

Microalgae strain catalogue:A strain selection guide for microalgae users: 4th edition

The 4th edition of this catalogue contains information on the cultivation and composition characteristics of 50 microalgae. Each entry includes relevant links to Atlantic Area stakeholders known to have a relevant connection with each of the species listed, be it in the form of culture collections, research expertise, technology developers, or biomass producers. We invite the readers to visit and/or join the EnhanceMicroAlgae Stakeholder database: an easily accessible, visual and open access database that brings together all the European Atlantic Area players working in the microalgae sector.This publication is part of the deliverables of the Interreg-funded international project EnhanceMicroAlgae. The authors gratefully acknowledge the European Regional Development Fund (ERDF) Interreg Atlantic Area programme which funded the EnhanceMicroAlgae project: EAPA_338/2016, "High added-value industrial opportunities for microalgae in the Atlantic Area"

Paradigm of magnetic domain wall-based In-memory computing

While conventional microelectronic integrated circuits based on electron charges approach the theoretical limitations in foreseeable future, next-generation nonvolatile logic units based on electron spins have the potential to build logic networks of low power consumption. Central to this spin-based architecture is the development of a paradigm for in-memory computing with magnetic logic units. Here, we demonstrate the basic function of a transistor logic unit with patterned Y-shaped NiFe nanowires by gate-controlled domain-wall pinning and depinning. This spin-based architecture possesses the critical functionalities of transistors and can achieve a programmable logic gate by using only one Y-shaped nanostructure, which represents a universal design currently lacking for in-memory computing

Multidimensional analysis reveals environmental factors that affect community dynamics of arbuscular mycorrhizal fungi in poplar roots

IntroductionPoplar is a tree species with important production and application value. The symbiotic relationship between poplar and arbuscular mycorrhizal fungi (AMF) has a key role in ecosystem functioning. However, there remain questions concerning the seasonal dynamics of the AMF community in poplar roots, the relationship between AMF and the soil environment, and its ecological function.MethodPoplar roots and rhizosphere soil were sampled at the end of April and the end of October. The responses of AMF communities to season, host age, and host species were investigated; the soil environmental factors driving community changes were analyzed.ResultsThe diversity and species composition of the AMF community were higher in autumn than in spring. Season, host age, host species, and soil environmental factors affected the formation of the symbiotic mycorrhizal system and the AMF community. Differences in the communities could be explained by soil pH, total nitrogen, total phosphorus, total potassium, available potassium, and glomalin content.DiscussionThe AMF community was sensitive to changes in soil physicochemical properties caused by seasonal dynamics, particularly total potassium. The change in the mycorrhizal symbiotic system was closely related to the growth and development of poplar trees

Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films

We have investigated the magnetic damping of precessional spin dynamics in defect-controlled epitaxial grown Fe3O4(111)/Yttria-stabilized Zirconia nanoscale films by all-optical pump-probe measurements. The intrinsic damping constant of the defect-free Fe3O4 film is found to be strikingly larger than that of the as-grown Fe3O4 film with structural defects. We demonstrate that the population of the first-order per- pendicular standing spin wave (PSSW) mode, which is exclusively observed in the defect-free film under sufficiently high external magnetic fields, leads to the enhancement of the magnetic damping of the uniform precession (Kittel) mode. We propose a physical picture in which the PSSW mode acts as an additional channel for the extra energy dissipation of the Kittel mode. The energy transfer from the Kittel mode to the PSSW mode increases as in-plane magnetization precession becomes more uniform, resulting in the unique intrinsic magnetic damp- ing enhancement in the defect-free Fe3O4 film

Early ACEI/ARB use and in-hospital outcomes of acute myocardial infarction patients with systolic blood pressure <100 mmHg and undergoing percutaneous coronary intervention: Findings from the CCC-ACS project

BackgroundFew studies have evaluated whether acute myocardial infarction (AMI) patients with relatively low blood pressure benefit from early ACEI/ARB use in the era of percutaneous coronary intervention (PCI).ObjectivesThis study evaluated the associations of ACEI/ARB use within 24 h of admission with in-hospital outcomes among AMI patients with SBP < 100 mmHg and undergoing PCI.MethodsThis study was based on the Improving Care for Cardiovascular Disease in China-ACS project, a collaborative registry and quality improvement project of the American Heart Association and the Chinese Society of Cardiology. Between November 2014 and December 2019, a total of 94,623 patients with AMI were enrolled. Of them, 4,478 AMI patients with SBP < 100 mmHg and undergoing PCI but without clinically diagnosed cardiogenic shock at admission were included. Multivariable logistic regression and propensity score-matching analysis were used to evaluate the association between early ACEI/ARB use and in-hospital major adverse cardiac events (MACEs), a combination of all-cause death, cardiogenic shock, and cardiac arrest.ResultsOf AMI patients, 24.41% (n = 1,093) were prescribed ACEIs/ARBs within 24 h of admission. Patients with early ACEI/ARB use had a significantly lower rate of MACEs than those without ACEI/ARB use (1.67% vs. 3.66%, p = 0.001). In the logistic regression analysis, early ACEI/ARB use was associated with a 45% lower risk of MACEs (odds ratio: 0.55, 95% CI: 0.33–0.93; p = 0.027). Further propensity score-matching analysis still showed that patients with early ACEI/ARB use had a lower rate of MACEs (1.96% vs. 3.93%, p = 0.009).ConclusionThis study found that among AMI patients with an admission SBP < 100 mmHg undergoing PCI, early ACEI/ARB use was associated with better in-hospital outcomes. Additional studies of the early use of ACEIs/ARBs in AMI patients with relatively low blood pressure are warranted

2D materials for conducting holes from grain boundaries in perovskite solar cells

Grain boundaries in organic-inorganic halide perovskite solar cells (PSCs) have been found to be detrimental to the photovoltaic performance of devices. Here, we develop a unique approach to overcome this problem by modifying the edges of perovskite grain boundaries with flakes of high-mobility two-dimensional (2D) materials via a convenient solution process. A synergistic effect between the 2D flakes and perovskite grain boundaries is observed for the first time, which can significantly enhance the performance of PSCs. We find that the 2D flakes can conduct holes from the grain boundaries to the hole transport layers in PSCs, thereby making hole channels in the grain boundaries of the devices. Hence, 2D flakes with high carrier mobilities and short distances to grain boundaries can induce a more pronounced performance enhancement of the devices. This work presents a cost-effective strategy for improving the performance of PSCs by using high-mobility 2D materials