Search Results (66)

Using equivalent transformations, complicated circuits in physics that need numerous mathematical operations to analyze can be broken down into simpler equivalent circuits. It is also possible to determine the number of spanning trees—graph families in particular—using these adjustments and utilizing our knowledge of difference equations, electrically equivalent transformations, and weighted generating function rules. In this paper, we derive the exact formulas for the number of spanning trees of sequences of new graph families created by a Johnson skeleton graph 63 and a few of its related graphs. Lastly, a comparison is made between our graphs’ entropy and other graphs of average degree four. Full article

Gas extraction is the main method to reduce the gas content of a coal seam and prevent coal and gas outburst. The sealing depth is one of the key parameters affecting the sealing effect. The principle of the high-density direct current method is to lay electrodes underground, and by injecting a stable DC current into the underground medium, the potential difference is measured to calculate the apparent resistivity, which reflects the difference in electrical conductivity of the underground rock or coal body, and then inferring the physical characteristics, such as its structure, water content, or stress state. Based on the basic principle of the high-density direct current method, this study analyzed the change rule of resistivity after the secondary stress of the roadway; tested the distribution of the roadway stress field in Juji Mine; and finally, determined the sealing depth of this coal seam. The main conclusions were as follows: The resistivity of the loose crushing zone after the roadway disturbance stress corresponded to the plasticity and destruction stage of the coal body, and the resistivity was larger compared with that of the original rock stress area. The stress concentration zone corresponded to the compression stage, where the destruction of the coal and rock state was smaller, and the resistivity was smaller compared with that of the original rock stress area. The range of the loose circle of the roadway of the coal seam was 6 m, and the range of the stress concentration zone was 6–17.5 m. The range of resistivity changes of the loose crushing zone was larger, and it had a large range of resistance, which had a good effect. The resistivity of the loose broken zone varied widely and was random, while the visual resistivity of the stress concentration zone was basically the same and was stable. Full article

While building the steel–concrete composite girder bridge by means of the incremental launching method, the steel box is directly in the sunlight, and the temperature impact should not be neglected. However, the existing specifications fail to offer the temperature gradient pattern applicable to the steel box featuring a significant height–width ratio and straight web. This paper, relying on the Fenshui River Bridge situated in the southwest region of China, carried out a temperature test. By analyzing the experimental data, the rules of temperature changes at the measuring points in various positions of the steel box were studied, and the temperature disparities of the steel box across different seasons were contrasted. Through the analysis of the test data, the rule governing temperature distribution across the height dimension of the cross-section and its change with time were studied, and a model designed to represent the temperature gradient within the steel box was put forward. By utilizing the numerical model, the effect of the temperature gradient on the force acting on the structure in the process of incremental launching was analyzed. The findings indicate that the temperature of the top plate of the steel box is the highest from 14:00 to 16:00. There is a lag phenomenon in the temperature rise in the bottom plate. The greatest temperature disparity between the upper and lower plates of the steel box is not always present in the season when the temperature is comparatively high. The curve of temperature gradient change exhibits nonlinear features, and the variation in temperature is considerable within the scope of 1 m. In this article, a double-broken line temperature gradient model is put forward, with the corresponding temperature gradient of 17.8 °C. The temperature gradient obviously affects the structural stress, changing the stress distribution, and it notably impacts the deformation. The deformation generated on the guide beam due to the temperature gradient makes up 39% of the total deformation. The temperature gradient is not a fixed value. When the steel box girder is under the jacking process, especially while the structure remains in its maximum cantilever condition and is about to cross the pier, the time should be avoided when the temperature gradient is at its highest. Full article

This research paper focuses on dimensionality reduction, which is a major subproblem in any data processing operation. Dimensionality reduction based on principal components is the most used methodology. Our paper examines three heuristics, namely Kaiser’s rule, the broken stick, and the conditional number rule, for selecting informative principal components when using principal component analysis to reduce high-dimensional data to lower dimensions. This study uses 22 classification datasets and three classifiers, namely Fisher’s discriminant classifier, logistic regression, and K nearest neighbors, to test the effectiveness of the three heuristics. The results show that there is no universal answer to the best intrinsic dimension, but the conditional number heuristic performs better, on average. This means that the conditional number heuristic is the best candidate for automatic data pre-processing. Full article

Basic principles of ferroelectric activity induced by the noncollinear alignment of spins are reviewed. There is a fundamental reason why the inversion symmetry can be broken by certain magnetic order. This situation occurs when the magnetic order simultaneously involves ferromagnetic ($\mathit{F}$) and antiferromagnetic ($\mathit{A}$) counterparts, transforming under the spatial inversion $\mathcal{I}$ and time reversal $\mathcal{T}$ as $\mathcal{I}\mathit{F}=\mathit{F}$ and $\mathcal{IT}\mathit{A}=\mathit{A}$, respectively. The incompatibility of these two conditions results in breaking the inversion symmetry, which manifests itself in the electric polarization $\overrightarrow{P}$. The noncollinear alignment of spins is one of examples of such coexistence of $\mathit{F}$ and $\mathit{A}$. This coexistence principle imposes a constraint on possible dependencies of $\overrightarrow{P}$ on the directions of spins, which can include only “antisymmetric coupling” in the bond, ${\overrightarrow{\mathcal{P}}}_{ij}·[{\mathit{e}}_i\times {\mathit{e}}_j]$, and “single-ion anisotropy”, ${\mathit{e}}_i·$ $\overrightarrow{\mathbb{\Pi }}$ ${\mathit{e}}_i$. Microscopically, ${\overrightarrow{\mathcal{P}}}_{ij}$ can be evaluated in the framework of superexchange theory. For the single Kramers doublet, this theory yields ${\overrightarrow{\mathcal{P}}}_{ij}\sim {\overrightarrow{\mathit{r}}}_{ij}^{\phantom{0}}$, where ${\overrightarrow{\mathit{r}}}_{ij}^{\phantom{0}}$ is the spin-dependent part of the position operator induced by the relativistic spin-orbit coupling. ${\overrightarrow{\mathit{r}}}_{ij}^{\phantom{0}}$ remains invariant under spatial inversion, providing the microscopic reason why noncollinear alignment of spins can induce $\overrightarrow{P}$ even in centrosymmetric crystals. The symmetry properties of ${\overrightarrow{\mathit{r}}}_{ij}^{\phantom{0}}$ can be rationalized from the viewpoint of symmetry of Kramers states. Particularly, the commonly used Katsura–Nagaosa–Balatsky (KNB) rule $\overrightarrow{P}\propto {\overrightarrow{ϵ}}_{ji}\times [{\mathit{e}}_i\times {\mathit{e}}_j]$ (${\overrightarrow{ϵ}}_{ji}$ being the direction of the bond $ij$) can be justified only for relatively high symmetry of the bonds. The single-ion anisotropy vanishes for the spin ${\displaystyle \frac{1}{2}}$ or if magnetic ions are located in inversion centers, thus severely restricting the applicability of this microscopic mechanism. The properties of multiferroic materials are reconsidered from the viewpoint of these principles. A particular attention is paid to complications caused by possible deviations from the KNB rule. Full article

Every year, more than 700,000 people die by suicide worldwide, a quarter of whom are between 15 and 29 years of age. In Spain, suicide has surpassed road traffic accidents as the leading non-natural cause of death in this age group. Although its overall incidence remains low, the number of suicide attempts continues to rise, indicating an upward trend. Despite being recognized as a significant public health issue, the media often refrains from reporting on suicide to prevent the Werther effect, thereby avoiding the potential propagation of suicidal behavior. This is a form of self-censorship in the exercise of freedom of information, a right recognized by the Spanish Constitution, which also undermines the right of citizens to receive such content. The Spanish Constitutional Court has determined that public interest is a mandatory requirement to endorse the legitimacy of a news item in case of a clash with any of the rights that legally limit freedom of information. This article aims to analyze whether, in those exceptional cases in which the rule of silence is broken, the information on suicide in young people is in line with the jurisprudential concept of public interest, above privacy, honor or self-image and, especially, above the protection of children and adolescents. As a research method, this study analyzes a selection of news articles on suicides of minors, published in Spanish digital newspapers and compiled into a self-developed database. These articles are examined through the lens of the Spanish Constitutional Court’s doctrine on freedom of information. The findings indicate that public interest is unequivocally justified when news coverage focuses on aggregated data regarding suicide or suicide attempts among minors. However, when reporting on the suicide of an individual minor, the justification from the perspective of freedom of information depends on the specifics of each case, requiring a careful balance between public interest and the protection of fundamental rights. Full article

In enterprises, managers often intentionally break the rules out of altruistic motives, which is called managerial pro-social rule breaking (MPSRB). Most studies have focused on its positive consequences, while its potential dark side is neglected and lacks exploration. To bridge this gap, based on the broken windows theory, this study tries to investigate the mechanism and boundary of MPSRB’s influence on employees’ workplace deviance, introducing organizational anomie as a mediating variable and normative conflict as a moderating variable. An experiment study and a time-lagged questionnaire survey were conducted in mainland China. The results revealed the following: MPSRB had a positive impact on the perceived organizational anomie of employees; organizational anomie mediated the influence of MPSRB on employees’ workplace deviance; normative conflict moderated the influence of MPSRB on organizational anomie; normative conflict negatively moderated the indirect effect of organizational anomie. This study provides a new perspective on the mechanism and boundary of the negative consequences of MPSRB and provides practical implications for enterprises to reduce the employees’ deviance caused by MPSRB. Full article

Multi-rotor drones have expanded their range of applications, one of which being search and rescue (SAR) missions using infrared thermal imaging. This paper addresses thermal target tracking with track segment association (TSA) for SAR missions. Three types of associations including TSA are developed with an interacting multiple model (IMM) approach. During multiple-target tracking, tracks are initialized, maintained, and terminated. There are three different associations in track maintenance: measurement–track association, track–track association for tracks that exist at the same time (track association and fusion), and track–track association for tracks that exist at separate times (TSA). Measurement–track association selects the statistically nearest measurement and updates the track with the measurement through the IMM filter. Track association and fusion fuses redundant tracks for the same target that are spatially separated. TSA connects tracks that have become broken and separated over time. This process is accomplished through the selection of candidate track pairs, backward IMM filtering, association testing, and an assignment rule. In the experiments, a drone was equipped with an infrared thermal imaging camera, and two thermal videos were captured of three people in a non-visible environment. These three hikers were located close together and occluded by each other or other obstacles in the mountains. The drone was allowed to move arbitrarily. The tracking results were evaluated by the average total track life, average mean track life, and average track purity. The track segment association improved the average mean track life of each video by 99.8% and 250%, respectively. Full article

Enterprises are currently facing difficult decisions due to the threats caused by the ongoing economic crisis, the war in Ukraine, and inflation. Due to broken supply chains, companies are struggling with rising costs and problems in the supply of raw materials. The economies have turned towards local markets. Companies are looking for ways to become independent from global suppliers and are trying to look for those who offer similar goods but in closer proximity to diversify supplies. Difficulties in recruiting appropriate staff cause problems related to staff turnover and changes in the organizational culture of the company. The research shows that companies focus less on strategies for entering new markets and focus on waiting out the difficult period and generating as few losses as possible. Companies that were already struggling with problems and did not manage to return to the pre-pandemic state after the pandemic are starting to implement a strategy of survival in the market. As research by other researchers indicates, innovation and the creation of new products are strongly related to the crisis. Companies, faced with changing market rules, are looking for new solutions. Companies that have been operating in the market longer cope better with changes and are more prepared for crises than young enterprises. Full article

This article discusses the issue of diagnosing low-power solar power plants using the five-valued (5VL) state evaluation {4, 3, 2, 1, 0}. We address in depth how the 5VL diagnostics built upon 2VL, 3VL, and 4VL—two-valued diagnostics, three-valued logistics, and four-valued diagnostics. Logic (5VL) assigns five state values to the range of signal value changes, and these states are completely operational ({4}), incomplete ({3}), critical efficiency ({2}), and pre-fault efficiency ({1}). For the identical ranges of diagnostic signal values, all three of the applied state valence logics interpret failure as changes outside of their permitted ranges. Diagnostic procedures made use of an AI-based DIAG 2 system. This article’s goal is to provide a comprehensive overview of the DIAG 2 intelligent diagnostic system, including its architecture, algorithm, and inference rules. Diagnosis with the DIAG 2 system is based on a well-established technique for comparing diagnostic signal vectors with reference signal vectors. A differential vector metric is born out of this examination of vectors. The input cells of the neural network implement the challenge of signal analysis and comparison. It is then possible to classify the object components’ states in the neural network’s output cells. Based on the condition of the object’s constituent parts, this approach can signal whether those parts are working, broken, or urgently require replacement. Full article

Hox gene clusters are crucial in embryogenesis. It was observed that some Hox genes are located in order along the telomeric to centromeric direction of the DNA sequence: Hox1, Hox2, Hox3…. These genes are expressed in the same order in the ontogenetic units of the Drosophila embryo along the anterior–posterior axis. The two entities (genome and embryo) differ significantly in linear size and in-between distance. This strange phenomenon was named spatial collinearity (SP). Later, it was observed that, particularly in the vertebrates, a temporal collinearity (TC) coexists: first Hox1 is expressed, later Hox2, and later on Hox3…. According to a biophysical model (BM), pulling forces act at the anterior end of the cluster while a cluster fastening applies at the posterior end. Hox clusters are irreversibly elongated along the force direction. During evolution, the elongated Hox clusters are broken at variable lengths, thus split clusters may be created. An empirical rule was formulated, distinguishing development due to a complete Hox cluster from development due to split Hox clusters. BM can explain this empirical rule. In a spontaneous mutation, where the cluster fastening is dismantled, a weak pulling force automatically shifts the cluster inside the Hox activation domain. This cluster translocation can probably explain the absence of temporal collinearity in Drosophila. Full article

Slicing 3D polygonal meshes is a fundamental operation in various applications such as virtual surgery, garment simulation, and game development. Existing methods primarily slice meshes using either a single line or a set of line segments approximating a smooth curve. This paper introduces a novel approach to freely slice a triangle mesh using a freeform curve without discretizing it into line segments. The user draws a stroke on the screen, defining the desired cutting trajectory. Subsequently, a freeform curve approximating this stroke is generated and extended into a ruled surface in the user’s viewing direction. To efficiently compute intersections between the ruled surface and a triangle mesh, the Line–Surface Intersection (LSI) problem is broken down into two subproblems: Plane–Curve Intersection (PCI) followed by Line–Line Intersection (LLI). Intersection points are then connected to form polylines, effectively cutting the mesh into multiple submeshes. To ensure the solidity of the submeshes, cross-sections are generated by trimming the ruled surface along the polylines and merged with the corresponding submeshes. Our method empowers users to slice triangle meshes along arbitrary trajectories encompassing both straight and freely curved paths while preserving efficiency and accuracy. The effectiveness of the proposed approach is demonstrated through experimental results showing various examples of mesh slicing. Full article

Horizontal wells within the roof are an effective method to develop gas in broken and soft coal seams, and layer-penetrating fracturing is a key engineering method for the stimulating of horizontal wells within the roof of a coal seam. To understand the propagation law of fracture in the composite roof of coal seams, this study conducted research using numerical simulation and physical similarity simulation methods. Furthermore, engineering experiments were carried out at the Panxie coal mine in the Huainan Mining Area and the Luling coal mine in Huaibei Mining Area, to further validate this technology. The numerical simulation results indicated that fracture within the coal seam roof can propagate from the roof to the target coal seam, effectively fracturing the coal seam. Due to the coal seam’s plasticity being greater than that of the roof mudstone, the coal seam forms a broader fracture than the roof. With the increase in pseudo roof mudstone thickness and being under constant fracturing displacement, the energy consumed by the pseudo roof mudstone during fracturing causes a decrease in pore pressure when fracture extends to the coal seam, resulting in a reduction in fracture width. Therefore, the pseudo roof mudstone is an adverse factor for the expansion of hydraulic fracturing. Physical similarity simulation results demonstrated that when horizontal boreholes were arranged within the siltstone of the coal seam roof, were under reasonable vertical distance and high flow rate fracturing via fluid injection conditions, and if the coal seam had a thin pseudo roof mudstone, the fracture could propagate through the direct roof-pseudo roof interface and the pseudo roof-coal seam interface, extending to the lower coal seam. The fracture form was curved and had irregular vertical fractures, indicating that hydraulic fracturing can achieve production enhancement and the transformation of soft and hard coal seams. However, when the coal seam had a thick pseudo roof mudstone, the mudstone posed strong resistance to hydraulic fracturing, making it difficult for the fracture to propagate to the lower coal seam. Therefore, the pseudo roof mudstone plays a detrimental role in hydraulic fracturing and the production enhancement of coal seams. The engineering verification conducted at Panxie coal mine and Luling coal mine showed that by utilizing a construction drainage rate of 7.5 cubic meters per minute at Panxie coal mine, the maximum fracture length reached 218.3 m, with a maximum fracture height of 36.8 m. The maximum daily gas production of a single well reached 1450 cubic meters per day, with a total gas extraction volume of 43.62 × 10⁴ cubic meters across 671 days. At Luling coal mine, utilizing a construction drainage rate of 10 cubic meters per minute, the maximum fracture length reached 169.1 m, with a maximum fracture height of 20.5 m. The maximum daily gas production of a single well reached 10,775 cubic meters per day, with a total gas extraction volume of 590 × 10⁴ cubic meters for 1090 days. This indicated that the fracture within the roof of coal seams can penetrate the composite roof of coal seams and extend to the interior of the coal seams, achieving the purpose of transforming fractured and low-permeability coal seams and providing an effective mode of gas extraction. Full article

Purine stretches, sequences of adenine (A) and guanine (G) in DNA, play critical roles in binding regulatory protein factors and influence gene expression by affecting DNA folding. Both purines can exist in the enol-amine form (often referred to as the imidazole form) and keto-imine forms. The enol-amine form is more stable and biologically significant than the keto-imine form. This enhanced stability is attributed to the fully conjugated ring system in the enol-amine form, which adheres to Hückel’s rule and becomes aromatic. The presence of a delocalized pi-electron cloud within this fully conjugated ring system results in an aromatic molecule. In contrast, the keto-imine form lacks full conjugation in its ring system due to a broken double bond between the nitrogen and carbon atoms, rendering it non-aromatic. This study investigates the relationship between purine stretches and cancer development, which makes mechanistic sense considering the aromaticity of purines in the purine stretches flanking each mutation. A pronounced avoidance of typical cancer mutations of long purine stretches in typical types of cancer was observed in the public data of patients in intergenic regions, suggesting the role of intergenic sequences in chromatin reorganization and gene regulation. A statistically significant shortening of purine stretches in cancerous tumors (p-value 0.0001) was found. The insights into the aromatic nature of purines and their stacking energies explain the role of purine stretches in DNA structure, contributing to their role in cancer progression. This research lays the groundwork for understanding the nature of purine stretches, emphasizing their importance in gene regulation and chromatin restructuring, and offers potential avenues for novel cancer therapies and insights into cancer etiology. Full article

In pursuit of realizing neuromorphic computing devices, we demonstrated the high-performance synaptic functions on the top-to-bottom Au/ZnVO/Pt two-terminal ferroelectric Schottky junction (FSJ) device architecture. The active layer of ZnVO exhibited the ferroelectric characteristics because of the broken lattice-translational symmetry, arising from the incorporation of smaller V⁵⁺ ions into smaller Zn²⁺ host lattice sites. The fabricated FSJ devices displayed an asymmetric hysteresis behavior attributed to the ferroelectric polarization-dependent Schottky field-emission rate difference in between positive and negative bias voltage regions. Additionally, it was observed that the magnitude of the on-state current could be systematically controlled by changing either the amplitude or the width of the applied voltage pulses. Owing to these voltage pulse-tunable multi-state memory characteristics, the device revealed diverse synaptic functions such as short-term memory, dynamic range-tunable long-term memory, and versatile rules in spike time-dependent synaptic plasticity. For the pattern-recognition simulation, furthermore, more than 95% accuracy was recorded when using the optimized experimental device parameters. These findings suggest the ZnVO-based FSJ device holds significant promise for application in next-generation brain-inspired neuromorphic computing systems. Full article