Selection Principle Research Articles

Research on UAV flight attitude control system based on simulink and genetic algorithm

With the evolution of networking and information technology, unmanned aerial vehicles (UAVs) have emerged as integral components in numerous fields, executing diverse and vital tasks. The accuracy and efficiency of UAV operations are greatly influenced by their attitude control systems, which dictate flight stability, speed, and functionality. However, traditional control methods for UAV flight stability and accuracy have become outdated, unable to meet the demands of modern applications. To address these challenges, this study introduces a novel attitude control approach based on genetic algorithms. This method utilizes the principles of natural selection and genetic traits to optimize the parameters of the attitude control system. The objective is to enhance the current control effectiveness, improve the UAV's maneuverability, and enable its versatile applications across multiple fields. Simulink tool simulations are conducted to evaluate the stability of the optimized results. This simulation tool allows for the replication of real-world flight conditions and the assessment of the attitude control system's performance under various scenarios. The results of these simulations provide valuable insights into the effectiveness of the genetic algorithm-based attitude control method. This study contributes to the advancement of UAV technology by improving the accuracy and stability of attitude control systems. It paves the way for more efficient and reliable UAV operations in various fields, from environmental monitoring to search-and-rescue missions, thus enhancing their operational capabilities and expanding their potential applications.

Wood utilized for wooden components in ancient buildings of Tingbao Yang’s former residence

Summary A comprehensive analysis was conducted using optical microscopy based on wood anatomy to enhance the preservation of wooden components in Tingbao Yang’s former residence. This study identified wood samples, and statistical examination of wood species, variations in their configuration, physical and mechanical properties, and natural durability were examined. The principles for wood species selection were assessed. Findings indicate that Cunninghamia lanceolata, Pseudotsuga spp., Populus spp. and Ulmus spp. are the primary choices for these wooden components. However, certain portions incorporate Larix sect. Multiseriales, Picea brachytyla, Pinus bungeana, Pinus massoniana, Castanea sp. and Quercus subg. Lepidabalanus, sect. Prinus. Pseudotsuga spp., C. lanceolata, Ulmus spp. and Populus spp. are primarily utilized for wooden columns and melon columns. However, C. lanceolata, Ulmus spp. and Populus spp. possess inadequate parallel grain compressive strength for load-bearing compression wooden components. C. lanceolata and Ulmus spp. are widely utilized in beams, lintels, purlins, and rafters owing to their exceptional bending strength. It was noted that Castanea sp. and Quercus subg. Lepidabalanus, sect. Prinus wood varieties demonstrate superior resistance to rotting and insects compared with other types of wood. The selection of wood species for the ancient buildings of Tingbao Yang’s former residence relies on crucial principles, such as the suitability of wood properties and local selection. This selection process involves analyzing the wood properties, assessing the natural durability of wooden components, and considering the distribution of forest resources in Henan Province.

Concept of Spaceborne Ocean Microwave Dual-Function Integrated Sensor for Wind and Wave Measurement

Dedicated to synchronously acquiring large-area, high-precision, and multi-scale ocean wind and wave information, a novel concept of a spaceborne ocean microwave dual-function integrated sensor is proposed in this paper. It integrates the functions of a scatterometer and SAR by sharing a single phased-array antenna. An overview of the scientific requirements and motivations for the sensor are outlined firstly. In order to fulfill the observation requirements of both the functions, the constraints on the system parameters such as frequency, antenna size, and incidence angle are analyzed. Then, the selection principles of these parameters are discussed within the limitations of antenna area, bandwidth, available time, and cost. Additionally, the constraints on the time sequence of transmitting and receiving pulses are derived to ensure that there is no conflict when the two functions operate simultaneously. Subsequently, a method for jointly designing the pulse repetition frequency (PRF) of both the functions is introduced, along with zebra maps to verify its effectiveness. At the end of the paper, the system and performance parameters of the sensor are given for further insight into it.

H-star-Lindelöf property and weaker versions

We introduce the selection principles H-star-Lindelöf, weakly H-star-Lindelöf and almost H-star-Lindelöf and we provide some propositions and relationships with other known properties in literature. Furthermore, in this paper we characterize the above selection principles in hyperspaces endowed with the hit-and-miss topology τΔ, by using a new property SSΠΔ(Λ),fin⋆(CΔ(Λ),B), for the corresponding choose of the family B.

Iterations and unions of star selection properties on topological spaces

In this paper, we investigate what selection principles properties are possessed by small (with respect to the bounding and dominating numbers) unions of spaces with certain (star) selection principles.. Furthermore, we give several results about iterations of these properties and weaker properties than paracompactness. In addition, we study the behaviour of these iterated properties on $\Psi$-spaces. Finally, we show that, consistently, there is a normal star-Menger space that is not strongly star-Menger; this example answers a couple of questions posed in [J. Casas-de la Rosa, S. A. Garcia-Balan, P. J. Szeptycki, \emph{Some star and strongly star selection principles}, Topology Appl. 258 (2019) 572-587]

Some Alternative Interpretations of Strongly Star Semi-Rothberger and Related Spaces

Abstract In this article, some under-appreciated characteristics of strongly star-Rothberger subsets are explored. Additionally, with the aid of the SSI property and MSSI property, semi-Rothberger and star semi-Rothberger spaces are represented by families of closed sets. Finally, several selection principle like attributes are produced that can reflect the previously mentioned sequential covering features in an inverted form.

Characteristics of Pre-peak Mechanical Damage and Energy Evolution of Typical Hard-rock in Diversion Tunnel under Cyclic Loading-Unloading

An in-depth understanding of the pre-peak mechanical damage and energy-evolution characteristics of typical hard-rock in a diversion tunnel under cyclic load is of great significance to promote the safe and efficient construction of the diversion tunnel and the stability of surrounding rock. To study the pre-peak mechanical characteristics and the competition mechanism between energy storage and energy dissipation of typical hard-rock in a diversion tunnel under cyclic loading-unloading, combined with the internal drilling and blasting excavation of the actual engineering rock mass and the external vehicle cyclic load environment of the diversion tunnel, the cyclic loadingunloading tests of typical granite and tuff in diversion tunnel were carried out. Based on the analysis principle of mechanics and energy, the strain variables, modulus variables, energy variables and damage variables of granite and tuff under cyclic loading-unloading test were defined. The cyclic mechanical properties and energyevolution characteristics of granite and tuff under pre-peak load were analyzed. The competition mechanism between pre-peak energy storage and pre-peak energy dissipation of granite and tuff and the evolution law of strain damage variable and energy damage variable were revealed. The selection principle of rock sample size and the limitation of the test scheme were further discussed. The study of the damage evolution of rocks close to failure (pre-peak stage) under cyclic load is helpful to better understand the damage and failure mechanism of rocks in practical engineering problems. Keywords: Diversion tunnel, Cyclic loading-unloading, Granite/Tuff, Blasting cyclic load, Energy evolution.

Antiangiogenic-immune-checkpoint inhibitor combinations: lessons from phase III clinical trials.

Antiangiogenic agents, generally antibodies or tyrosine-kinase inhibitors that target the VEGF-VEGFR pathway, are currently among the few combination partners clinically proven to improve the efficacy of immune-checkpoint inhibitors (ICIs). This benefit has been demonstrated in pivotal phase III trials across different cancer types, some with practice-changing results; however, numerous phase III trials have also had negative results. The rationale for using antiangiogenic drugs as partners for ICIs relies primarily on blocking the multiple immunosuppressive effects of VEGF and inducing several different vascular-modulating effects that can stimulate immunity, such as vascular normalization leading to increased intratumoural blood perfusion and flow, and inhibition of pro-apoptotic effects of endothelial cells on T cells, among others. Conversely, VEGF blockade can also cause changes that suppress antitumour immunity, such as increased tumour hypoxia, and reduced intratumoural ingress of co-administered ICIs. As a result, the net clinical benefits from antiangiogenic-ICI combinations will be determined by the balance between the opposing effects of VEGF signalling and its inhibition on the antitumour immune response. In this Perspective, we summarize the results from the currently completed phase III trials evaluating antiangiogenic agent-ICI combinations. We also discuss strategies to improve the efficacy of these combinations, focusing on aspects that include the deleterious functions of VEGF-VEGFR inhibition on antitumour immunity, vessel co-option as a driver of non-angiogenic tumour growth, clinical trial design, or the rationale for drug selection, dosing and scheduling.

Natural Selection, Scarcity and Evil:

It is often claimed that our knowledge of the evolutionary process adds an extra dimension to the classical problem of natural evil and makes this problem worse. Especially the principle of natural selection is often portrayed as morally inappropriate or “unfitting” for a perfectly good God to use as a means for creating biological complexity. In this article, I argue that this common view is misconceived, and that natural selection is a wholly innocuous principle. The real source of evolutionary evils is the fact that resources in nature are scarce – a fact that was known long before Darwin. The problem of natural and evolutionary evil, therefore, is best construed as a question about why God permits scarcity in nature. I argue that recent research about the interrelation between competition and cooperation in the evolutionary process provides resources for answering this perennial question in a more satisfactory way than could be done before the advent of evolutionary theory.

Navigating phase diagram complexity to guide robotic inorganic materials synthesis

Efficient synthesis recipes are needed to streamline the manufacturing of complex materials and to accelerate the realization of theoretically predicted materials. Often, the solid-state synthesis of multicomponent oxides is impeded by undesired by-product phases, which can kinetically trap reactions in an incomplete non-equilibrium state. Here we report a thermodynamic strategy to navigate high-dimensional phase diagrams in search of precursors that circumvent low-energy, competing by-products, while maximizing the reaction energy to drive fast phase transformation kinetics. Using a robotic inorganic materials synthesis laboratory, we perform a large-scale experimental validation of our precursor selection principles. For a set of 35 target quaternary oxides, with chemistries representative of intercalation battery cathodes and solid-state electrolytes, our robot performs 224 reactions spanning 27 elements with 28 unique precursors, operated by 1 human experimentalist. Our predicted precursors frequently yield target materials with higher phase purity than traditional precursors. Robotic laboratories offer an exciting platform for data-driven experimental synthesis science, from which we can develop fundamental insights to guide both human and robotic chemists.

Using the Cuckoo Optimization to Initialize the Harmony Memory in Harmony Search Algorithm to Find New Hybrid (CSHS) Algorithm

The current paper seeks to present a hybrid harmony search algorithm, using CS and HS. The proposed algorithm takes advantage of using a method to initialize the harmony memory (HM) with the help of the cuckoo search optimization algorithm. The HS algorithm is inspired by the method used by musicians to create and enhance harmony in music. It follows 3 main principles of pitch adjustment (PA), HM consideration (HMC), and random selection (RS). The performance of HS can be affected by its poor accuracy in optimization and speed of convergence, 2 main issues with it. However, to improve the HS algorithm, Cuckoo search can be used as it can do a local search using one parameter only, other than the size of the population, making it work more efficiently. This current method has been tested for its validity and efficiency in performance by being implemented on many international standard optimization problems. The results confirm the fact that the performance of the currently proposed algorithm is better and more efficient in finding solutions compared to HS and other algorithms.

Numerical simulation of 3D concrete printing derived from printer head and printing process

Ensuring the repeatability and stability of printing process is significant for the 3D Concrete Printing (3DCP). However, the diversity of printers often leads to unpredictable printing journeys. Hence, in this study the printer head was dimensionally characterized by three factors: channel diameter, neck height, and nozzle diameter. The effects of printer head and process parameters (travel speed, extrusion flow rate, and nozzle height) on the geometry stability and shape of printed filament were investigated with computational fluid dynamics method. The results indicated that, for printing materials without coarse aggregates, extrusion methods had a negligible impact on 3DCP process. For the printer head, the nozzle diameter dominated the geometry stability while the neck height and channel diameter had little effects. A dimensionless parameter φ was proposed to quantitatively analyze the influences of travel speed, extrusion flow rate, and nozzle diameter. The systematic mechanical analysis indicated that the geometry instability (tearing and meandering) was controlled by the φ and nozzle height. Based on the above analysis, the selection principle for printing parameters was proposed to ensure a stable and repeatable printing. The research results regarding printer heads and printing parameters can greatly promise the large-scale application of 3DCP.

Stochastic processes under parameter uncertainty

In this paper we study a family of nonlinear (conditional) expectations that can be understood as a stochastic process with uncertain parameters. We develop a general framework which can be seen as a version of the martingale problem method of Stroock and Varadhan with parameter uncertainty. To illustrate our methodology, we explain how it can be used to model nonlinear Lévy processes in the sense of Neufeld and Nutz, and we introduce the new class of stochastic partial differential equations under parameter uncertainty. Moreover, we study properties of the nonlinear expectations. We prove the dynamic programming principle, i.e., the tower property, and we establish conditions for the (strong) USCb–Feller property and a strong Markov selection principle.

The library information resources of the Scientific Library of Yanka Kupala State University of Grodno

The author examines the experience of Yanka Kupala State University Library (Grodno, Belarus) in providing digital document resources to its users. The proprietary information resources are reviewed; the selection principles for library Internet-resources are specified; user awareness services are described. The library organizes information educational workshops intended for the faculty, though it experiences some problems in disseminating information on library services and resources, in particular, students’ low interest in information literacy and lacking teaching hours for library courses. The author suggests several possible solutions and prospective vectors for the academic library, i. e. development of proprietary resources, corporate collaboration, improvement, development and introduction of new methods of user services. The author emphasizes the importance of improving librarians’ professional competences in providing reliable and enhanced information.

Exploring the perspectives of transwomen on ethical issues in conducting research with the transwomen community in India: A qualitative enquiry

Background Research with or involving transwomen in India is limited; previous research has focused on understanding the problems and discriminations they face. However, no studies have focused on exploring the ethical dimension of conducting research among transwomen. This kind of research is important for true representation but is only possible when cis-gender researchers engage with transgender perspectives. The study aimed at identifying the perspective of transwomen regarding the need to undertake research among them, understanding their perspectives of research ethics and articulating requirements to ensure their inclusion in research. Methods The study was an exploratory study using qualitative research methods, conducted with transwomen in Kolkata, West Bengal, India, in collaboration with a transgender led community-based organisation. The National Ethical Guidelines for Biomedical and Health Research involving Human Participants by the India Council for Medical Research was the reference point for this exploration with focus on select research ethics principles and allied ethical aspects. Results Insights into the perspectives of the transwoman from this research include: research among transgender persons is much needed to understand the trans way of life, identify problems and possible solutions; researchers should be mindful of the preferred nomenclature, invest in rapport building; ensure research is done in a safe space; the results are reported in a way that does not increase stigma and the research findings are used for the benefit of the community. Conclusions While conducting research among trans-communities is important, it is essential that before starting any research with transgender persons, researchers should carefully examine questions related to who benefits from the proposed research, whether the proposed study is meaningful to the trans-community, whether it address their immediate and pressing needs and finally whether it furthers the stigma that transgender persons are subjected to, before embarking on the study.

Communities of practice in art and design teaching in higher education: Considering the literature

This article provides an overview of relevant literature related to the broader research area of communities of practice, and indicates relationships between this literature and the disciplinary context of art and design teaching in Higher Education. Initially the rationale for selection of literature is provided, then the specific disciplinary context of the research area is indicated, through the lens of signature pedagogies, in order to situate the research in context and explore the use of these pedagogies in relation to learning and teaching art and design. Communities of practice, and developments within this concept, are explored, providing an understanding of how learning and teaching may occur in practically focused subject areas. Finally insights from both bodies of literature are synthesised to indicate implications for art and design in higher education, and opportunities for further research.

A Study on the C-E Translation of Chinese Public Notices from the Perspective of Adaptation Theory

Nowadays, public notices translation is one of the main research fields in translation studies. This paper applies Adaptation Theory to analyze the characteristics of Chinese public notices in Chinese-to-English translation. At the same time, according to the linguistic characteristics of Chinese public notices, such as variability, negotiation and conformity, this paper discusses the current status and purpose of the research on the translation of Chinese public notices. The paper also uses Adaptation Theory to analyze the textual and linguistic characteristics of lexical, syntactic, and stylistic aspects and adopts appropriate translation strategies following the principle of selection and conformity, so as to achieve the purpose of conformity.

Therapeutic Plasma Exchange in AChR-Ab Positive Generalized Myasthenia Gravis: A Real World Study About Its Early Response.

Since there is no clear priority or selection principle in the guidelines for myasthenia crisis, therapeutic plasma exchange (TPE) and intravenous immunoglobulin are often administered randomly. However, it should be more prudent in taking TPE due to its higher cost and risk. Studying its early response factors is crucial for managing myasthenia crisis and can improve medical and economic benefits. A prospective observational study was conducted, and patients classified as having "impending myasthenia crisis" or experiencing a myasthenia crisis and treated by TPE were included. The primary endpoint was the response after TPE. Univariate logistic regression analysis and repeated measurement were performed to analyze factors related to TPE efficacy. A total of 30 patients who treated with TPE as their fast-acting treatments were enrolled. After TPE, those whose QMGs and/or MGCs decreased by ≥5 points or ≥30% of the baseline were judged as "response group", accounting for 66.67% (20/30). Respiratory symptoms had a response rate of 72.00% (18/25), showing the most remarkable improvement. Meanwhile, extraocular symptoms were the least sensitive, with only 8.00% (2/25) showing efficacy. Thymoma (100.00% vs 50.00%, P=0.002) and a high concentration of AChR-Ab (37.37 nmol/L vs 25.4 nmol/L, P=0.039) were common in the early response group. Repeated measures showed significant changes in AChR-Ab and CD19+ B cells before and after TPE (all with P < 0.05). After treatment, the CD19+ B cells tended to decrease in the response group. These results indicated that, for AChR-Ab positive generalized MG, TPE can quickly improve respiratory symptoms. Thymoma and a high concentration of AChR-Ab before TPE predict an early better response. Additionally, TPE may work by decreasing AChR-Ab levels and inducing immune regulation. Future prospective and randomized controlled studies are needed.

An invariance constrained deep learning network for partial differential equation discovery

The discovery of partial differential equations (PDEs) from datasets has attracted increased attention. However, the discovery of governing equations from sparse data with high noise is still very challenging due to the difficulty of derivatives computation and the disturbance of noise. Moreover, the selection principles for the candidate library to meet physical laws need to be further studied. The invariance is one of the fundamental laws for governing equations. In this study, we propose an invariance constrained deep learning network (ICNet) for the discovery of PDEs. Considering that temporal and spatial translation invariance (Galilean invariance) is a fundamental property of physical laws, we filter the candidates that cannot meet the requirement of the Galilean transformations. Subsequently, we embedded the fixed and possible terms into the loss function of neural network, significantly countering the effect of sparse data with high noise. Then, by filtering out redundant terms without fixing learnable parameters during the training process, the governing equations discovered by the ICNet method can effectively approximate the real governing equations. We select the one-dimensional (1D) Kuramoto–Sivashinsky equation, the two-dimensional (2D) Burgers equation, the equation of two-dimensional channel flow over an obstacle, and the equation of three-dimensional (3D) intracranial aneurysm as examples to verify the superiority of the ICNet for fluid mechanics. Furthermore, we extend similar invariance methods to the discovery of wave equation (Lorentz Invariance) and verify it through single and coupled Klein–Gordon equation. The results show that the ICNet method with physical constraints exhibits excellent performance in governing equations discovery from sparse and noisy data.

On the cogent formulation of an elastomeric silicone ink material for direct ink write (DIW) 3D printing

AbstractAdhesives and sealants show fine rheology with good physical and mechanical properties as viscous pastes, a possible starting point for developing direct ink writing (DIW) 3D printing ink. However, many commercial adhesives and sealants take days or weeks to cure fully. DIW 3D‐printed parts made directly from these sealants are not designed for a scalable manufacturing process and high‐volume production. Moreover, most of these adhesives and sealants have volume shrinkage during cure. A systematic understanding of formulation methods and design principles for an elastomeric silicone DIW ink can overcome these issues. This study presents the cogent formulation development of a 3D printable thermoset elastomer silicone that gels and cures isotropically in minutes, reducing cycle time for rapid ink development with no shrinkage during cure. More specifically, we outline the principles of raw material selection of a formulation to achieve excellent rheology, printability, synchronized working, and gel time fitting requirements closer to scalable manufacturing. The reaction kinetics and their corresponding 3D‐printed structural properties are also described. Interest in future work is toward a rational DIW 3D printing ink material development protocol and use of machine learning (ML).Highlights Formulation method flexibility and design principle of DIW ink. Raw material selection principle to achieve optimal rheology for DIW printing. Ink gel kinetics for large‐scale DIW manufacturing. Hydrosilylation conversion over time at different ambient temperatures. Structural properties of DIW 3D printed parts.