Hard Property Research Articles

Drift versus Shift: Decoupling Trends and Changepoint Analysis

We introduce a new approach for decoupling trends (drift) and changepoints (shifts) in time series. Our locally adaptive model-based approach for robustly decoupling combines Bayesian trend filtering and machine learning based regularization. An over-parameterized Bayesian dynamic linear model (DLM) is first applied to characterize drift. Then a weighted penalized likelihood estimator is paired with the estimated DLM posterior distribution to identify shifts. We show how Bayesian DLMs specified with so-called shrinkage priors can provide smooth estimates of underlying trends in the presence of complex noise components. However, their inability to shrink exactly to zero inhibits direct changepoint detection. In contrast, penalized likelihood methods are highly effective in locating changepoints. However, they require data with simple patterns in both signal and noise. The proposed decoupling approach combines the strengths of both, that is, the flexibility of Bayesian DLMs with the hard thresholding property of penalized likelihood estimators, to provide changepoint analysis in complex, modern settings. The proposed framework is outlier robust and can identify a variety of changes, including in mean and slope. It is also easily extended for analysis of parameter shifts in time-varying parameter models like dynamic regressions. We illustrate the flexibility and contrast the performance and robustness of our approach with several alternative methods across a wide range of simulations and application examples.

Algebraic solution and thermodynamic properties for the one- and two-dimensional Dirac oscillator with minimal length uncertainty relations

We study the quantum characteristics of the Dirac oscillator within the framework of Heisenberg's generalized uncertainty principle. This principle leads to the appearance of a minimal length of the order of the Planck length. Hidden symmetries are identified to solve the model algebraically. The presence of the minimal length leads to a quadratic dependence of the energy spectrum on the quantum number n, implying the hard confinement property of the system. Thermodynamic properties are calculated using the canonical partition function. The latter is well determined by the method based on Epstein's zeta function. The results reveal that the minimal length has a significant effect on the thermodynamic properties.

Gate Assignment Algorithm for Airport Peak Time Based on Reinforcement Learning

In existing airport gate allocation studies, little consideration has been given to situations where gate resources are limited during peak periods. Under such circumstances, some flights may not be able to make regular stops. In this paper, the airport gate assignment problem under peak time is investigated. We propose a gate pre-assignment model to maximize the gate matching degree and the near gate passenger allocation rate. Besides, to minimize the pre-assignment gate change rate, we propose a dynamic reassignment model based on the pre-assignment model. By considering the non-deterministic polynomial hard (NP-hard) property of this problem, a gate assignment algorithm based on proximal policy optimization (GABPPO) is proposed. The simulation results show that the algorithm can effectively solve the gate shortage problem during the airport peak period. Compared with the adaptive parallel genetic, deep Q-network, and policy gradient algorithms, the target value of solutions obtained by the proposed algorithm in the near gate passenger allocation rate is increased by 5.7%, 3.6%, and 7.9%, respectively, and the target value in the gate matching degree is increased by 10.6%, 4.9%, and 11.5% respectively.

Structure and magnetic properties of melt-spun Mn-Ga-Cu-Al ribbons

In this work, we investigated structure and magnetic properties of Mn65Ga20Al15−xCux (x = 0, 5, 10 and 15) alloy ribbons prepared by melt-spinning method combined with annealing. The annealing temperature was varied from 250 °C to 350 °C, and the annealing time was changed from 5 h to 20 h. Concentration of Cu and annealing process significantly influence on the formation of the desired phases in the alloy ribbons. The D022-type Mn3Ga crystalline phase with the hexagonal structure, which characterizes hard magnetic property of Mn-Ga based alloys, is enhanced after an appropriate annealing process. The change of grain size after annealing also contributes to the increased coercivity of the alloy ribbons. The highest coercivity of 12.9 kOe and saturation magnetization of 18.7 emu g−1 are achieved on the alloy ribbons with Cu concentration of 10%. The simultaneous enhancement of these magnetic parameters has an important significance for application possibility of the Mn-Ga based alloys.

ANALYSIS OF TiFe INTERMETALLIC COMPOUND BY DFT

The structural, mechanical, anisotropy, and optical properties of the TiFe compound, which is the effective hydrogen storage material, were analyzed using the DFT method with the CASTEP program. The elastic constants of the cubic system, which have been determined by the stress-strain method, are stable according to the Born stability criteria. According to the mechanical properties, the compound was brittle and hard. Anisotropy properties were examined in 2D and 3D with the EIAM code. Finally, the optical properties using the complex dielectric function based on the electronic structure of TiFe; parameters such as dielectric constants, reflectivity, extinction coefficient, refractive index, and loss function were examined in the range of 0-50 eV. Generally, our obtained results are comparable with literature values.

Surface Integrity Analysis in Grinding of Dual-Phase High-Entropy Alloy

Abstract High-entropy alloys (HEAs) are highly anticipated because of their superb properties in strength, hardness, wear resistance, etc. However, compared with numerous studies on the design and properties of HEAs, the machinability research of HEAs is extremely rare, which limits the application of HEAs. In this work, grinding experiments of (FeCoNi)86Al7Ti7 dual-phase HEA workpieces were carried out, and the results are analyzed from a general machinability perspective (the machining parameters’ effect on grinding force and surface roughness) to a more in-depth perspective, including grinding-induced changes in morphology and microstructure on the ground surface and subsurface. With scanning electron microscope (SEM) and electron backscatter diffraction (EBSD) information of subsurface, the deformation mechanisms have been studied, including the role of the second-phase (Ni2AlTi) in the grinding process, the material removal modes of the different phases, and the morphology of the nanoprecipitates in the matrix, based on the completely opposite properties of different phases in HEA. It is noticed that the hard and brittle property of the second phase brings support to the material, reduces the plastic deformation, and also makes its own removal brittle, while the plastic matrix experiences shear deformation in grinding, which makes the nanoprecipitates in it assume different morphologies. These detailed findings could be of help to understand the effect of grinding on material properties so as to improve the machining quality of this material.

Basic kirwan injectivity and its applications

Abstract Consider the Hamiltonian action of a torus on a transversely symplectic foliation that is also Riemannian. When the transverse hard Lefschetz property is satisfied, we establish a foliated version of the Kirwan injectivity theorem and use it to study Hamiltonian torus actions on transversely Kähler foliations. Among other things, we prove a foliated analogue of the Carrell–Liberman theorem. As an application, this confirms a conjecture raised by Battaglia–Zaffran on the basic Hodge numbers of symplectic toric quasifolds. Our methods also allow us to present a symplectic approach to the calculation of the basic Betti numbers of symplectic toric quasifolds.

Faraday effect in CoPt-CaF2 nanogranular films with hard magnetic property for magnetic-field-free faraday devices

Magneto-optical Faraday devices, such as optical isolators, require a structure to apply a magnetic field to the incorporated magneto-optical material. The application of a magnetic field hinders the miniaturization and integration of these devices. Nanogranular films show Faraday rotation angles up to 40 times larger than Bi-YIG in the optical communication band (1,550 nm). Nanogranular films are submicron-to several-micrometer-thick and contribute to the miniaturization and integration of optical devices. Here, we introduce (Co-Pt)–(CaF2) nanogranular films exhibiting a magnetic-field-free magneto-optical Faraday effect, which are Co3Pt alloy that are hard magnets with residual magnetization. These nanogranular films exhibit the Faraday effect without requiring a magnetic field owing to their residual magnetization.

Research on neural network algorithm in artificial intelligence recognition

With the rapid development of computer application technology, computer artificial intelligence recognition technology has also made rapid progress. Artificial intelligence was first represented by LISP language, machine theorem proof, etc., and then the intelligent medical treatment and neural network appeared, and now it realizes the popularization of AI. The purpose of this article is to explore the application of neural network algorithms in artificial intelligence recognition. Based on the classic convolutional neural network with LeNet structure, this paper constructs a reasonable convolutional neural network model by deepening and expanding, and uses it in face recognition to conduct face recognition research. LeNet is the origin of CNN, and LeNet is mainly used to identify and classify handwritten characters. This paper uses three networks on the YaleB face database for face recognition, and compares the pooling method of the maximum pooling and average pooling, the misclassification rate of the ReLU incentive function and the tanh incentive function on the three networks.YaleB is a very complete face database, divided into five subsets, ten people, and 64 images per person, including changes in illumination, expressions, and gestures. The tanh function has what is an odd function and has a soft saturation property, while the relu function has a hard saturation property. Analyze whether it can solve the problems caused by illumination factors and occlusion factors in traditional face recognition. Finally, the recognition effect is compared with the traditional face recognition method, and it is concluded that the effect of the traditional face recognition method is not as high as the misclassification rate of 0.0356 based on the convolutional neural network. The recognition method works well. Maximum pooling is also known as maximum reduced pixel sampling, and is more based on the input element map than average pooling.Through the optimization of the algorithm, the face recognition rate is improved, which helps the application and development of artificial intelligence.

Hard Lefschetz Property for Isometric Flows

The hard Lefschetz property (HLP) is an important property which has been studied in several categories of the symplectic world. For Sasakian manifolds, this duality is satisfied by the basic cohomology (so, it is a transverse property), but a new version of the HLP has been recently given in terms of duality of the cohomology of the manifold itself in [1]. Both properties were proved to be equivalent (see [2]) in the case of K-contact flows. In this paper, we extend both versions of the HLP (transverse and not) to the more general category of isometric flows, and show that they are equivalent. We also give some explicit examples which illustrate the categories where the HLP could be considered.

Growth of high-quality CrI3 single crystals and engineering of its magnetic properties via V and Mn doping

CrI3, as a soft van der Waals layered magnetic material, has been widely concerned and explored for its magnetic complexity and tunability. In this work, high quality and large size thin CrI3, V and Mn doped single crystals were prepared by chemical vapor transfer method. A remarkable irreversible Barkhausen effect was observed in CrI3 and CrMn0.06I3, which can be attributed to the low dislocation density that facilitates movement of the domain walls. In addition, the introduction of the doping element Mn allows higher saturation magnetization intensity. Cr0.5V0.5I3 exhibits substantially increased coercivity force and larger magnetocrystalline anisotropy compared to CrI3, while kept similar Curie temperature and good environmental stability. The first principles calculations suggest direct and narrowed band gaps in Cr0.5V0.5I3 and VI3 comparing to CrI3. The smaller band gaps and good hard magnetic property make Cr0.5V0.5I3 an alternative choice to future research of spintronic devices.

Tuning the structural, electronic, mechanical and optical properties of silicene monolayer by chemical functionalization: A first-principles study

Commercial purposes of two-dimensional silicene are usually suppressed in nanoelectronic and optoelectronic devices by its zero-band gap. Here, the halogen atoms are detected to open the bandgap of silicene monolayer by the chemical functionalization, and comprehensive analysis of the effects of halogenation on the structural, electronic, mechanical and optical properties are conducted via first-principles calculations within the framework of density functional theory. Our simulation results prove that the halogenation makes silicene structure more distorted but maintains good stability. Specifically, Full- and Janus-functionalization endow silicene with direct bandgap ranging from 1.536 to 2.123 eV by the HSE06 functional, while half-functionalization renders silicene metallic and retains semiconducting characteristics. In the above three configurations, the bond between the halogen atom and the host Si atom is predominantly ionic and the ionicity of the former two configurations decreases as the period number of the halogen atom increases. Furthermore, the halogenated silicene monolayers exhibit a hard mechanical property and relatively strong ability to resist deformation based on calculated Young's modulus Y and Shear modulus G except for the F–Si monolayer. And the light absorption of pristine silicene monolayer is increased by halogenation in the UV–Vis light spectrum.

Hard Times, Property Crimes, and the Perils of Making Shift: The Working Poor in Jacksonian-Era Cumberland County, Pennsylvania

Hard Times, Property Crimes, and the Perils of Making Shift:The Working Poor in Jacksonian-Era Cumberland County, Pennsylvania Michael B. McCoy (bio) Abstract This essay draws on an uninterrupted stretch of indictment records from 1827 to 1846 to consider the relationship between hard times and property crimes in rural Pennsylvania. Focusing on working poor defendants, the piece illustrates how struggling men and women used petty crime as a makeshift response to material hardship and how such a strategy often led to more hard times. By examining the ways in which economic conditions and crime together shaped the lives of laboring people in a rural setting, this essay adds to the rich historiographies of working-class experience and crime in Pennsylvania. Demonstrating that rural crime was born of the same struggle for survival as it was in the Jacksonian city, the essay ultimately suggests that, amid capitalist transformation, the material lives of urban and rural working people—if they were ever that different—grew increasingly uniform. Property Crime, The Working Poor, Jacksonian Economy, Rural Poverty, Makeshift Strategies James gutshall was no stranger to hard times. The Cumberland County, Pennsylvania, "laboring man" was perennially poor, owned little in the way of personal property, was consistently absent from the tax rolls, and struggled to support his "wife and large family." In January 1833, with his prospects few and his problems many, Gutshall crafted a crude $7 promissory note and went shopping at John Ross's Dickinson Township store. Riddled though it was with errors, the note was evidently passable enough to allow him to walk out of Ross's store with eight yards of fabric, three handkerchiefs, one bandana, three pounds of coffee, three rolls of tobacco, and a two-dollar credit toward future purchases. Realizing his mistake, Ross quickly sought the assistance of John Auld, a [End Page 55] justice of the peace. Auld ordered the sheriff to undertake a "diligent search in the day time" of Gutshall's home, secure any or all of the goods in question, and bring Gutshall before the justice "to be examined . . . and further to be dealt with according to the law." The next day, Gutshall was arrested and confined to the county jail. More than two months would pass before he would face trial. Appearing before the quarter sessions in April, Gutshall was swiftly indicted, convicted, and sentenced to three months' confinement, saddled with a $21 fine, and ordered to pay court costs. Already grim, Gutshall's financial situation deteriorated in the months following his conviction. From his jail cell in June 1833, he petitioned the court of common pleas for relief from mounting debts and legal fees. Time lost to imprisonment left him and his family with mounting debts to local storekeepers. Unable to work, he could not pay his court-imposed fine, let alone the ever-increasing jailers' fees. Freed sometime after his August 12, 1833, insolvency hearing, Gutshall turned his attention to recovering from the economic consequences of conviction. Lost time, lost wages, and a damaged reputation would, however, haunt him for years to come; in 1837, he would again seek the aid of the insolvency court.1 Confronted by the uncertainties and material hardships that attended the Jacksonian economy, Gutshall had few options for patching the holes in his family's budget—all of them temporary, and none of them very good.2 For Gutshall, and poor men and women like him, making ends [End Page 56] meet in the face of poverty and an uncertain market for their labor often meant making shift: relying upon a handful of short-term strategies, both licit and otherwise, including the poorhouse, outdoor relief, charitable assistance, buying on credit, and petty crime.3 Faced with the struggle for subsistence, Gutshall turned to property crime, a decision that led not to relief but instead to deeper financial hardship. Gutshall's experiences as a working man and a defendant offer insight into the convergence of economic insecurity and crime in the lives of rural working people.4 Indeed, his story, and the stories of those like him, illustrate how the working poor used crime as a makeshift response to material hardship and the...

Architectural Significance of Granite and Other Durable Rocks in the Context of India – An Analytical Study

Architectures created through the cutting of naturally occurred massive rocks include different structures, buildings, tombs, monuments, caves and sculptures. On account of hard and tough property, the granite is considered as strong construction stone in human history. Granite is very common in the continental crust of our mother earth. It is characterised as coarse grained plutonic intrusive igneous rock and is composed of quartz, alkali feldspar and plagioclase. Typical mineralogical character and textural varieties of granite facilitates to develop a wide range of colours, which include white, pink and grey etc. Granite rocks established itself as praiseworthy architecture stone since historical past because of its distinctive character like durability, appreciable finishing, fascinating polish nature and above all its magnificent colour diversities. As architectural stone, the granitic rocks demand attraction owing to the combination of style and elegance. The application of granitic rocks is witnessed in the ancient world through the mesmerising major architectures in India and around the world like Mount Rushmore, Washington Monument, Great Pyramid of Giza; Ajanta and Ellora caves, monolithic structure in the Zagwe-built Lalibela in Ethiopia along with in most of the long-lived old Indian temples, old forts and monuments etc. The monolithic free-standing architecture is generally rock-cut structures as depicted in the Ellora Kailasanathar Temple. The biggest monolithic statue in world, the Gommateshwara statue of Bahubali at Shravanabelagola present in the Indian state at Karnataka was carved in the 983 CE from a single block of granite rock. The radioactivity stuff in the granite is an important concern to the people in recent world. Even though the impact of radioactivity is proved mostly very less harmful to mankind, current research indicates that few granite products are showing radioactive substance index beyond permissible limit of the specified standard, which is responsible for environmental pollution during the use for long. Therefore, due attention is required towards the pertinent issue of radioactivity in the granite stones. Apart from granite, many of the architectures in India are created by the other rock types that include rocks like sedimentary, metamorphic and igneous rocks.

Studying structural, magnetic and morphological features of electrochemically fabricated thin films of Co–Ni–Fe with different Fe compositions

In this work, a detailed study on the influence of the Fe composition on the crystallite size, lattice parameter, crystallographic texture, coercive field (Hc), magnetic squareness ratio (SQR), domain structure, surface roughness and grain size in electroplated Co–Ni–Fe deposits was carried out. For this aim, Co–Ni67, Co–Ni61–Fe6 and Co–Ni54–Fe13 thin films with different Fe compositions were fabricated using electrochemical deposition technique. The results showed that the composition of Fe in the deposit depends on the concentration of Fe ions in the electroplating solution. An increase in the Fe composition caused a noticeable reduction in the size of crystallites and induced a considerable enhancement in the strength of the preferred orientation being in the [111] direction. It was also observed that an increase in the Fe composition makes the lattice parameter larger. Compared to other deposits, the Co–Ni54–Fe13 with the highest Fe composition exhibited a lower surface roughness and a more compact nodular surface topography consisting of relatively finer grains. All deposits displayed a stripe domain (SD) structure, an in–plane magnetic hysteresis loop with a vertical magnetization component and a semi–hard magnetic property. However, the Hc value, SQR parameter and SD width varied in accordance with the Fe composition.

Constant delay systolic binary counter with variable size cellular automaton based prescaler

An One-Dimension (1D) Cellular Automaton (CA) is studied as a generator for the radix-2 sequence, presenting suitable characteristics for the design of a fast and constant delay synchronous digital counter. The main contribution of this work is the proposal of a new type of synchronous digital counters including a CA-based prescaler and consecutive counting modules of various configurations (in terms of bitlength, speed and area requirements) to result in a modular and systolic counting structure with the minimum redundant hardware and low-power operation. It is the first time that a thorough exploration of the 1D CA rule 102 is offered and considered as the prescaler of a systolic counter of heterogeneous modules in size, achieving the desired constant delay characteristic with low area/power penalty. The proposed counter, compared to hard Intellectual Property (IP) cores, presents up to 90% enhancement of speed for 9.37%–33.0% area penalty for reconfigurable technologies.

Efficiency-fairness trade-offs in evacuation management of urban floods: The effects of the shelter capacity and zone prioritization.

With increasing flood risk, evacuation has become an important research topic in urban flood management. Urban flood evacuation is a complex problem due to i) the complex interactions among several components within a city and ii) the need to consider multiple, often competing, dimensions/objectives in evacuation analysis. In this study, we focused on the interplay between two such objectives: efficiency and fairness. We captured the evacuation process in a conceptual agent-based model (ABM), which was analyzed under different hard infrastructure and institutional arrangement conditions, namely, various shelter capacity distributions as a hard infrastructure property and simultaneous/staged evacuation as an institutional arrangement. Efficiency was measured as the time it takes for a person to evacuate to safety. Fairness was defined by how equally residents suffered from floods, and the level of suffering depended on the perceived risk and evacuation time. Our findings suggested that efficiency is more sensitive to the shelter capacity distribution, while fairness changes more notably according to the evacuation priority assigned to the divided zones in staged evacuation. Simultaneous evacuation generally tended to be more efficient but unfairer than staged evacuation. The efficiency-fairness trade-off was captured by Pareto-optimal strategies, among which uniform capacity cases led to a higher efficiency while prioritizing high-risk residents increases fairness. Strategies balancing efficiency and fairness featured a uniform capacity and prioritized high-risk residents at an intermediate time delay. These findings more clearly exposed the interactions between different factors and could be adopted as benchmarks to inform more complicated evacuation ABMs.

Study on a new high-entropy alloy Nd20Pr20La20Fe20Co10Al10 with hard magnetic properties

High-entropy alloys (HEAs) are a new class of alloys that consist of at least five major elements in equimolar or near-equimolar ratios with atomic concentration between 5% and 35%. Many HEAs containing the ferromagnetic elements Fe, Co and Ni show soft magnetic properties, while few HEAs present hard magnetic properties. In this paper, we design and prepare the Nd20Pr20La20Fe20Co10Al10 HEA with hard magnetic property. The magnetic property and microstructure of this alloy have been investigated. The intrinsic coercivity (Hcj), saturation magnetization (Ms), and remanence (Mr) of Nd20Pr20La20Fe20Co10Al10 alloy is 280.0 kA/m, 14.0 Am2/kg and 8.9 Am2/kg, respectively, which is slightly lower than 301.0 kA/m, 14.9 Am2/kg and 9.6 Am2/kg of Nd60Fe20Co10Al10 bulk amorphous alloy. The elasticity modulus (Er) of Nd20Pr20La20Fe20Co10Al10 alloy is 58.7 GPa, 4.6% higher than that of Nd60Fe20Co10Al10 alloy. SEM results show that there are two kinds of amorphous phases with different chemical compositions. TEM results show that Nd (Pr) and La nanocrystals are embedded in the amorphous matrix. The high coercivity of the alloy may originate from the combined effect of exchange coupling and domain wall pinning. Our findings provide a new idea to design HEAs with hard magnetic property leading to widen their applications.

Brain Storm Optimization-Based Edge Caching in Fog Radio Access Networks

In this paper, the hierarchical cooperative caching problem in fog radio access networks (F-RANs) is investigated. To minimize the content request delay, we formulate the hierarchical cooperative caching optimization problem based on local content popularity to find the optimal caching policy, where both horizontal cooperation among fog access points (F-APs) and vertical cooperation between the cloud server and F-APs are jointly considered. Considering the non-deterministic polynomial hard (NP-hard) property of this problem, we propose a brain storm optimization (BSO) approach which utilizes the penalty-based fitness function in individuals evaluation to meet the storage capacity constraint and the genetic algorithm (GA) in new individuals generation to meet the integer constraint, respectively. Moreover, to improve the initialization performance of the BSO approach, we propose to utilize Opposition-based Learning(OBL) to improve the initial solution space. To further reduce the computational complexity, we propose to implement the convergent operation in the objective space via individuals classification. We then analyze the global convergence and computational complexity of the proposed policy theoretically. Simulation results show that our proposed BSO-based hierarchical cooperative caching policy achieves remarkable performance in minimizing the content request delay.

THE ROLE OF DEPOSITION TEMPERATURE ON PARTICLE SIZE, ROUGHNESS PARAMETERS, MAGNETIC AND STRUCTURAL FEATURES OF ELECTROCHEMICALLY GROWN Ni–Fe/ITO SAMPLES

In this work, the impact of the deposition temperature (DT) on the particle size, roughness parameters, coercive force, squareness and structural features of the Ni–Fe samples electrochemically deposited onto glasses covered with indium tin oxide (ITO) was researched. An increase in the DT from 20 to 40 °C led to a very slight increase in the Fe concentration of the samples, revealing that the effect of the DT on the chemical composition was insignificant. The crystal structure was a face–centered cubic (fcc) and the preferred growth orientation was in the [111] direction irrespective of the DT. The crystallization of the samples improved, the size of the crystallites increased and the strength of the [111] growth orientation diminished with the DT. An increment in the DT resulted in a strong enhancement in the particle size and surface roughness. Further surface analysis indicated that the sample surface had a well spread out height distribution at the DT of 40 °C, while the sample surfaces at lower DTs 20 and 30 °C had narrow height distributions. In addition to that, the peaks were found to be predominant on the sample surfaces at lower DTs (20 and 30 °C), whereas the deep valleys were predominant on the sample surface at the DT of 40 °C. Magnetic measurements confirmed the existence of a semi–hard magnetic property in all samples. Compared to other samples produced at lower DTs (20 and 30 °C), the Ni–Fe sample electroplated at the DT of 40 °C possessed the highest coercive force and squareness values. Moreover, the magnetic characteristics of the samples were compatible with their morphological and structural characteristics.