Limited Space Research Articles

Twisted Metasurfaces for On‐Demand Focusing Localization

AbstractDynamic focusing of electromagnetic (EM) waves is a cornerstone in various applications, encompassing aerospace communication, sensing, and high‐resolution imaging. Recently, the advent of intelligent metasurfaces, hailed as the next evolutionary step, has revolutionized self‐adaptive functionalities. However, their extensive embeddings of active components pose a great challenge associated with escalated costs, heightened power consumption, and increased complexity, thus hindering large‐scale implementation. Here, a cost‐effective approach for dynamic EM focusing utilizing a twisted metasurface is introduced, which integrates a transmissive layer with a reflective layer in a cascade fashion. This innovative design leverages the mutual rotation between two layers to enable the precise manipulation of beam propagation and scanning area, allowing for the flexible localization of the focal point across a wide range, spanning −44.17° to 44.17° in elevation and 0° to 360° in azimuth. This capability is underpinned by the strategic fusion of multiple phase profiles, including gradient and Gaussian phase. In the experiment, a goal‐oriented system is built up whose outcomes demonstrate a striking alignment with the simulated results, achieving a correlation coefficient of 96.7%. This work presents a streamlined pathway toward dynamic EM focusing and the related applications constrained by space and power limitations.

Thermal Infrared Image Georeferencing using an Ensemble of Land Cover Predictions

Abstract. Precise georeferencing of remote sensing data is usually implemented in a post-processing fashion and is a crucial step for Earth observation applications such as change detection, natural hazard management, and ground target tracking. It is particularly important for small satellites intending to perform temperature monitoring and wildfire detection on a global scale wherein the precise location of fire is to be communicated. The cost-efficient navigating systems on board such satellites are often not capable of providing accurate geolocation information directly due to space and power limitations. Therefore, it is very important to have a globally applicable georeferencing refinement framework that is robust against illuminational and time-relevant scene changes. In this paper, we propose a georeferencing framework for thermal infrared images that consists of ensemble matching of deep learning-based land cover predictions to archival, well-georeferenced land cover maps. We verify the proposed framework on the georeferencing of single-band Landsat thermal imagery. Experimental results show the efficiency and practicality of the method with 72% of the test images geolocated within 1-pixel accuracy with no trajectory information available.

(Wo)Man-Made Public Space

Women experience limitations in public space regarding their safety, comfort, and accessibility, which might be mitigated by urban design. This article addresses the question: How can public space become more gender-inclusive through the implementation of design principles focused on meeting the needs of women? It draws on existing literature combined with empirical observations and interviews, to establish a framework of eight design principles (safety cues, informal surveillance, legibility, spatial appropriation, representation, diversity, slow modes and ease of use) to make public spaces more gender-inclusive. The principles are applied in an exemplary design case focused on a public street in the city centre of Heerlen, Netherlands , which currently faces many of the issues that are especially limiting to women. Active public spaces, meaning spaces that encourage user engagement and interaction, often already contain some elements outlined in the framework, leading to easier fulfilment of the design principles. The application of the principles is limited to one design case, and the focus is restricted to women’s experiences. When applying the principles in other cases or typologies, the implications of the proposed design guidelines need to be carefully considered.

Single-antenna super-resolution positioning with nonseparable toroidal pulses

The fundamental principle of satellite/node-based positioning involves triangulating the receiver’s coordinates through the intersection of spatial distances. Advancements in hybrid wireless networks have yielded high-precision positioning at decimeter-level (wavelength-level), approaching the resolution limits in free space. Here we present a 3D super-resolution positioning paradigm in free space by utilizing a kind of topologically structured pulses, toroidal electromagnetic pulses. We demonstrate that the space-time nonseparability and skyrmion topology inherent in toroidal pulses can be harnessed to achieve freespace microwave 3D positioning with super-resolution accuracy, reaching the centimeter level, using a single emitting antenna. This work opens up avenues for exploring the potential applications of topological electromagnetic pulses including but not limited to positioning, imaging and sensing technologies.

An exploration of teaching reform of management course based on rain class and participatory teaching under OBE concept

Management is the core course of business administration majors. In order to drive educational modernization through educational informatization, this article explores the teaching reform of management based on the concept of learning output education (OBE). It is guided by student output and follows the principle of "reverse design and positive implementation". In terms of implementation, it is specifically divided into learning goal reconstruction, course content integration The teaching process and the construction of an evaluation system are four steps. During the teaching process, the implementation of rain classroom and participatory teaching mode has broken through traditional time and space limitations, extending the interaction and communication between teachers and students from the classroom to pre class and post class, achieving a good loop of "pre class in class after class". This teaching reform practice can promote the improvement of the quality of management teaching and is conducive to cultivating high-quality management talents.

Комментарий очерка Сергея Слонимского «Скандалист поневоле: хроника хронического стресса – 1972-1991» из книги «Заметки на полях нотной тетради»

The article continues the publication and commentary of S. M. Slonimsky’s 2002 essay “An Unwilling Scandalmonger: A Chronicle of Chronic Stress – 1972-1991” from the book “Notes in the Margin of a Music Score”. Due to space limitations, the entire material of the essay is divided into three parts: the first article is dedicated to the post-war period of the author’s life until the beginning of the 1970s. The second (this) article explores events from the composer’s life and work in 1972-1991. The following, third article will cover the last decade of the 20th century and the beginning of the 21st century, 1992-2002. The focal points of the author’s reflections in the second essay of the “chronicle of chronic stress – 1972-1991” are also themes of moral and ethical issues within the composer’s society. These themes are explored in a different light – in direct connection with S. M. Slonimsky’s life in chronological order. The essay covers the second half of the 20th century and the beginning of the 21st century. The writing of this commentary is driven by the intensifying crisis of moral values in contemporary society. The author concludes: one should “focus on only one painful moment, quite typical of my creative and life path. Perhaps scandalous storms are my cross, the fateful predetermination of my destiny. Perhaps it is a fatal necessity for an independent person walking their own path, not wanting to prudently submit to those in power, to what promises peace, recognition, success, prosperity, and happy success. That is how I am, and that is how I will remain until the end <…> In my work, my philosophical worldview, personal traits of my emotional temperament, and my attitude towards many people inhabiting Russia, Europe, Asia, our entire earth are absolutely obvious.” As a result of the study, Slonimsky’s unwavering commitment to the established moral and ethical order and his uncompromising stance against manifestations of evil, envy, and betrayal in the composers’ milieu and music teaching have been identified and confirmed.

Towards bootstrapping F-theory

We consider type IIB string theory with N D3 branes and various configurations of sevenbranes, such that the string coupling gs is fixed to a constant finite value. These are the simplest realizations of F-theory, and are holographically dual to rank N Argyres-Douglas conformal field theories (CFTs) with SU(2) and SU(3) flavor groups, and Minahan-Nemeschansky CFTs with E6, E7 and E8 flavor groups. We use the Seiberg-Witten curves of these theories to compute the mass deformed sphere free energy F (m) at large N in terms of novel matrix models with non-polynomial potentials. We show how F (m) can be used along with the analytic bootstrap to fix the large N expansion of flavor multiplet correlators in these CFTs, which are dual to scattering of gluons on AdS5 × S3, and in the flat space limit determine the effective theory of sevenbranes in F-theory. As a first step in this program, we use the matrix models to compute the log N term in F (m) and thereby fix the logarithmic threshold in the AdS5 × S3 holographic correlator, which matches the flat space prediction.

Tensor Network State Algorithms on AI Accelerators.

We introduce novel algorithmic solutions for hybrid CPU-multiGPU tensor network state algorithms utilizing non-Abelian symmetries building on AI-motivated state-of-the-art hardware and software technologies. The presented numerical simulations on the FeMo cofactor, which plays a crucial role in converting atmospheric nitrogen to ammonia, are far beyond the scope of traditional approaches. Our large-scale SU(2) spin adapted density matrix renormalization group calculations up to bond dimension D = 216 on complete active space (CAS) size of 18 electrons in 18 orbitals [CAS(18, 18)] demonstrate that the current limit of exact solution, i.e. full-CI limit, can be achieved in fraction of time. Furthermore, benchmarks up to CAS(113, 76) demonstrate the utilization of NVIDIA's highly specialized AI accelerators via NVIDIA Tensor Cores, leading to performance around 115 TFLOPS on a single node supplied with eight NVIDIA A100 devices. As a consequence of reaching 71% of the full capacity of the hardware, the cubic scaling of computational time with bond dimension can be reduced to a linear form for a broad range of D values; thus, breaking the current computational limits of small CAS spaces in ab initio quantum chemistry and material science is becoming a reality. In comparison to strict U(1) implementations with matching accuracy, our solution has an estimated effective performance of 300-500 TFLOPS, which emphasizes the mutual need for both algorithmic and technological developments to push current frontiers on classical computation.

A new frequency domain denoising method for coal mine transient electromagnetic measuring data

Abstract Due to limitation of space in mine tunnel, only a 2m × 2m rectangle coil can be employed to collect the electromagnetic signals for the mine transient electromagnetic analysis. Hence, a small emission magnetic moment and weak detection signal strength will increase the electromagnetic analysis difficulty. Moreover, the transient electromagnetic response signal in mines exhibits exponential decay over time, with late-stage amplitudes being notably small, which makes these signals susceptible to noise interference. As a result, it is necessary to study effective noise removal methods to enhance the signal-to-noise ratio of the late-stage electromagnetic data. Addressing this challenge task, this study proposes a new method for frequency domain denoising of transient electromagnetic data. This new method utilizes the Fourier Transform to convert the original transient electromagnetic data from the time domain to the frequency domain, and then, the noise is identified and removed through the frequency characters. Lastly, the processed frequency domain information is transformed to the time domain by the Fourier Inverse Transform to restore the time domain signals. The effect of this frequency domain denoising method is demonstrated through numerical simulations and underground coal mine field data to show significant noise reduction performance on the abnormality detection in the underground coal mine.

Evaluation of space efficiency criteria in high-rise buildings based on functions: a case study of Türkiye

ABSTRACT High-rise buildings have become a significant solution to address the challenges posed by the rapid growth of urban populations and space limitations in cities. Efficient planning and design of these buildings, aiming to achieve more productivity, can be realized through ensuring space efficiency. This research compares architectural and structural design criteria affecting space efficiency in high-rises based on their functions, aiming to assess the degree of correlation among these criteria, space efficiency, and their interrelations. Currently, no studies examine the differences or similarities in space efficiency of high-rise buildings based on their functions. Additionally, selecting buildings from the same region as samples is a unique aspect of this study. Employing a case study method, the analysis encompasses 42 high-rises in Türkiye, ranging from 100 m to 300 m, and utilizes correlation analysis methods to examine the data. The comprehensive review of space efficiency in high-rises, based on their functions, yielded the following results: (i) Space efficiency ranged from 82.7% to 65.2% in high-rise case studies with different functions, with an average of 73.2%. (ii) A significant majority (83%) of the buildings followed orthogonal designs. (iii) Central core floor planning emerged as the preferred approach. (iv) Increasing elevator density reduced space efficiency. (v) Office buildings favored reinforced concrete frame systems, while residential buildings commonly used reinforced concrete shear wall systems. (vi) As building height increased, elevator and core areas expanded. These findings provide guidance for future high-rise building design and planning.

Eguchi–Hanson metrics arising from Kähler–Einstein edge metrics

Calabi–Hirzebruch manifolds are higher-dimensional generalizations of both the football and Hirzebruch surfaces. We construct a family of Kähler-Einstein edge metrics singular along two disjoint divisors on the Calabi–Hirzebruch manifolds and study their Gromov–Hausdorff limits when either cone angle tends to its extreme value. As a very special case, we show that the celebrated Eguchi–Hanson metric arises in this way naturally as a Gromov–Hausdorff limit. We also completely describe all other (possibly rescaled) Gromov–Hausdorff limits which exhibit a wide range of behaviors, resolving in this setting a conjecture of Cheltsov–Rubinstein. This gives a new interpretation of both the Eguchi–Hanson space and Calabi’s Ricci flat spaces as limits of compact singular Einstein spaces.

A twist at infinite distance in the CHL string

We analyze a space-time algebra of BPS states that emerges in the infinite distance limit in the moduli space of the nine-dimensional CHL string as the theory decompactifies to the ten-dimensional E8 × E8 heterotic string. We find an affine algebra as expected from the heterotic case, but in a twisted version.

Implementasi Pojok Literasi Sebagai Strategi Penigkatan Literasi Siswa di Lingkungan SDN 1 Tongka Kalimantan Tengah

This community service program was implemented to address the low literacy levels among students in remote areas of Central Kalimantan, specifically at SDN 1 Tongka, Gunung Timang District, North Barito Regency. The main objective of the program was to implement a literacy corner as a strategy to improve student literacy and create a sustainable literacy ecosystem in the school environment. The method used included participatory and adaptive approaches, applying the concept of a "mobile literacy corner" adapted to the limitations of local space and resources. The program was carried out over 45 days, covering preparation, implementation, and evaluation phases. The results showed a significant increase in students' reading interest, with a 68% rise in the frequency of visits to the literacy corner. Pre-test and post-test evaluations indicated an average increase in students' literacy skills of 27%, particularly in reading comprehension and vocabulary mastery. Participatory observation revealed the formation of a stronger literacy culture in the school environment, characterized by student-initiated literacy discussions and increased use of references in academic tasks. The program also successfully developed an adaptive and contextual model for implementing literacy corners, which has the potential to be replicated in other remote areas of Indonesia.

Sustainability of Digital Friendship: Insights from Early Buddhist Mettā

One of the significant effects of technology on human relations is visible in friendship. Positively technology through its digital spaces is facilitating friendship that is instant and beyond the limitations of time and space. However, such digital friendships that operate through social media often suffer from issues of trust and sustainability. To resolve this predicament, we need to pause and reflect on how digital friendship can be reframed to improve its sustainability in a practical manner. The primary purpose of this article is to examine how helpful the early Buddhist concept of mittatā (friendship) is in sustaining friendship in the digital age. The article begins by eliciting the moral challenges people encounter in online friendships. The objective is to highlight the need for a more vital concept of friendship, such as the early Buddhist concept of mittatā, that can mitigate the moral concerns in digitized friendship, making it genuine and sustainable. The subsequent part of the article offers an overview of some of the significant theories of friendship upheld in the West and examines whether they can support the sustainability of a digitized friendship. The objective is to reflect upon the lacuna in the practice of such ideas of friendship in the contemporary digital age. To replenish the lacuna, the following section articulates the early Buddhist concept of mittatā as a noble concept of friendship that can be morally relevant and sustainable in this digital world. Based on the philosophical study of the early Buddhist literature, the present article investigates how helpful mettā (loving kindness) in this society to sustain a trustworthy friendship. It proposes an ethical and noble way to nurture and savour an honourable friendship relevant to the digital era by inculcating specific virtues advocated by the Buddha.

A dimensional design of tractor seat based on Iranian anthropometric characteristics.

The dimensional seat design process should consider both the users' tasks and their physical characteristics. To use an approach for the design and evaluation of seat dimensions based on the anthropometric characteristics of the Iranian population and the requirements of tractor operators. Some existing equations relating the seat dimensions to anthropometric characteristics were modified according to logical justifications and international standards. A new mathematical-statistical method was used to extract the equations estimating the constant seat dimensions based on the theoretical maximizing of the accommodation level. In addition, an Overall Seat Accommodation Score (OSAS) was developed to represent the mean of seat dimensions accommodation level and dimensional accommodation equality, simultaneously. The dimensional seat design can be affected under different conditions of adjustability, esthetic, and space limitations. However, it was shown that it is possible to improve the design of tractor seats without any significant increase in the final cost and complexity. A new approach was used for tractor seats for a sample of Iranian operators and can be used for the design and evaluation of tractor seats for other target populations.

Relationship between greenery and the health of Madrid's citizens

The increase in parks will be one of the interventions in future cities to reduce pollution and enhance the quality of life. However, it is crucial to identify the variables within parks that have the most significant impact on well-being and health, given the substantial limitation of urban space. Different parks in Madrid were analyzed in this study, and simultaneously with the recording of environmental variables, their users were surveyed. The study's hypothesis aimed to determine whether the activities carried out in the parks have a greater impact on health than their mere presence. The quality of parks is an influential factor in these relationships; therefore, the quality of the acoustic environment was considered. The results indicate that the quality of the soundscape is a significant factor in the development of various activities and the overall perception of the park, making it a variable to consider in the design and improvement of the quality of green spaces. Greenery visibility is significantly related to the perception of health status, but this relationship is less intense than that provided by frequent activities in these green spaces such as walking and relaxation.

Numerical study of the vibration control performance of Kelvin foam

Vibration control in microsystems is an important challenge. Because of the space limitation, structures that consume minimal space but provide effective performance need to be identified. In this research, we evaluate the vibration damping performance of various Kelvin-cell structures in microsystems using the Finite Element Method. Nine types of unit cells are designed based on the tetrakaidecahedron with different geometric parameters. The lattices are composed of the aforementioned unit cells, and two types of boundary condition are set according to the actual application scenarios. The results of the simulation include dissipated energy , isolation efficiency, etc. The results are compared with each other and two types of non-Kelvin-cell structures. This comparative analysis aims to inform the development of space-efficient vibration absorbers for microsystems.

Strength and ductility of concrete columns reinforced with hybrid steel-fiber reinforced polymer composite bars

Using hybrid reinforcement scheme, comprising steel-FRP composite bar (SFCB) and FRP tie, holds great promise in developing seawater sea-sand concrete (SSC) columns with high strength and ductility for marine infrastructures. However, the impacts of FRP tie configurations on hybrid-reinforced SSC columns have not been thoroughly investigated, which hinders their application. To fill this research gap, this study conducted axial compression tests on hybrid-reinforced SSC columns to assess the impacts of tie type, tie size, tie spacing, and tie size/spacing configuration. The failure mechanism of columns, compressive contribution of SFCBs, and confinement mechanism of FRP ties were revealed. The results show that within the tie spacing limit, the failure mode, elastic modulus, yield strength, and ultimate strength of SFCBs are similar. Longitudinal SFCBs effectively resist compression until concrete crushing, providing considerable compressive contributions. However, the confinement efficiency of pultruded FRP ties is limited by the slip of lap splice and the inferior bent portions. In contrast, the closed-type FRP ties exhibit significantly higher confinement efficiency, which increases the load capacity and ductility of columns by 13.6% and 82.8%, respectively. The tie spacing limit was determined and a prediction model of load capacity was proposed based on theoretical analysis and experimental validation.

Study on Impact of Entertainment in the Context of Digital Capitalism on Youth Development

The development of electronic Internet technology has led to the construction of another world - a world constructed by data, or numbers of all kinds, where real-life individuals meet in another world in a “virtual body” state, and where the limits of time and space are completely broken. The limitations of time and space are completely broken. This has brought great convenience to the media industry and new business opportunities to capital. Major digital platforms have a huge number of Internet users, and after collecting their personal data and browsing information, they can accurately deliver content that may be of interest to them. In addition, the boom in the culture and entertainment industry has led to platforms putting icons in front of the public and making them objects of imitation and admiration. People are exposed to the data network constructed by mature technology, and the digitalisation and digital industrialisation of the industry have become a general trend. Stars, the money-making tools of capital, are being created in various ways, forming a complete industrial chain and controlling the vast number of Internet users. Teenagers, as active users of the Internet, are still at the stage of forming their values, so the various idol stars launched by the media industry have a huge impact on their development. The media industry, controlled by capital, pays more attention to economic benefits and sometimes even ignores social benefits in order to realise its value proliferation, seriously misleading young people whose values are not yet set and increasing the scope and intensity of capital exploitation, which urgently needs to be regulated and corrected by measures taken by the relevant authorities.

Exploring Effective Paths for Artificial Intelligence to Empower Freshmen's Autonomous English Learning in an “Internet Plus” Environment

In the environment of "Internet plus", the combination of artificial intelligence technology and education has broken the time and space limitations of autonomous learning, subversively changed the way students learn, and brought more possibilities and challenges to both teachers' "teaching" and students' "learning". It brings more possibilities and challenges for both teachers' "teaching" and students' "learning". This study takes the freshmen non-English majors of Beijing Institute of Petrochemical Technology as the research object, based on the multiple intelligences theory and the constructivist learning theory, investigates the status and ability of freshmen's autonomous learning of English in the context of the era of "Internet plus", and explores the effects of the learning tools and learning environments supported by the new technology of artificial intelligence on students’ autonomous learning ability and learning effect. It explores the impact of learning tools and learning environment supported by the new technology of artificial intelligence on students’ autonomous learning ability and learning effect, so as to further explore the effective path to improve students' English autonomous learning ability. It provides empirical data support and suggestions for autonomous learning research and university English teaching, and facilitates teachers to make scientific adjustments in the selection of teaching content, monitoring of teaching platforms, design of teaching activities, and application of teaching methods to promote the improvement of students' autonomous learning ability, and at the same time, it also helps students to identify their problems in autonomous learning, find effective paths to solve the problems, and improve their learning efficiency.