Compact Form Research Articles

Model complexity optimization of equivalent dynamical linearization data models used in model‐free adaptive control

AbstractThis paper discusses a strategy for optimizing the complexity of time‐varying data models as used in model‐free adaptive control (MFAC). Here the dynamic linearization in compact form (CFDL), partial form (PFDL), and full form (FFDL) are considered as data models used to describe input/output (I/O) data sets. These data models are built only for control purpose and can have various degrees of complexity depending on the size of the considered time‐window as well as the underlying algorithms. The methodology is to compare the performance of the data models according to an evaluation criterion, to analyze the order of different data models based on bias‐variance trade‐off, and to select the best‐performing model. The complexity of the selected model is compared with the reduced linear time‐invariant (LTI) model obtained by applying a combination of the eigensystem realization algorithm (ERA) and observer/Kalman filter identification (OKID) on the same I/O dataset. The I/O data are obtained from applying the MFAC controllers on a nonlinear three‐tank system (3TS) to track various desired references. The results indicate that the model complexity optimization can also be used for selecting an appropriate MFAC data model with optimal order to reduce the complexity and computational burden of the MFAC control algorithms.

Generalized mathematical model applied to a silica sand laboratory-controlled mill: Derivation of simplified ceramic ball entrance flux, ball wear consumption, and mass distribution functions

A laboratory-controlled milling process of silica sand was carried out using aluminum oxide balls of three different sizes. The ball wear kinetic equations were experimentally obtained from the evolution curves of the ball diameter as a function of the operating time. From a generalized model, the ball entrance flux and ball wear consumption were calculated using exact two-parameter solution functions. One-parameter ball entrance flux and ball wear consumption functions were proposed to perform calculations that accurately describe the values provided by the two-parameter functions. In addition, a compact form of the ball mass distribution function is found. This set of simplified equations can be suitable for fast calculations in the milling industry.

Wide FOV metalens for near-infrared capsule endoscopy: advancing compact medical imaging

Abstract This study presents the design, fabrication, and characterization of a wide field-of-view (FOV) metalens optimized for capsule endoscopy. The metalens achieved a 165° FOV with a high modulation transfer function (MTF) of 300 lines per millimeter (lp/mm) across the entire FOV, operating in the near-infrared (NIR) narrow-bandpass imaging at 940 nm. The performance of the metalens-based system is evaluated using two bandwidths, 12 nm and 32 nm, showing MTF values of 0.2 and 0.3 at 250 lp/mm, respectively. The metalens-based system maintains a compact form factor with a total track length of 1.4 mm and a diameter of 1.58 mm. Compared to a traditional 108° FOV endoscope, the nano-optic capsule endoscope demonstrated superior performance in terms of FOV, contrast, and resolution. This advancement represents a significant step toward enhancing diagnostic capabilities in medical imaging, offering improved performance in a more compact package compared to conventional optics.

High dynamic range land wavefield reconstruction from randomized acquisition

Compressive sensing (CS) is an alternative to regular Shannon sampling that captures similar information from reduced measurements. It relies on randomized sampling patterns and a sparse data representation to reconstruct the regularly sampled object. CS is an important ingredient in affordable seismic acquisition, which can lead to improvements in the near-surface mapping and noise suppression for land data. However, the near surface traps most of the source-generated energy, resulting in data that are rich in high-wavenumber content and have amplitudes spanning several orders of magnitude. When dealing with such high dynamic range nonstationary data, the Fourier domain is not optimal for providing a sparse representation — a necessary condition for successful application of CS. In contrast, a discrete complex wavelet transform can localize high-energy features, has good directional selectivity, and is near-shift invariant. Combined, these properties allow complex wavelets to represent detail-rich wavefields in a compact form. To leverage these features and achieve good CS reconstructions, we develop a scale- and orientation-dependent iterative soft thresholding (IST) scheme for reconstructing high dynamic range wavefields. Our approach requires little parameterization, is easy to implement, and is robust to reconstructed wavefield sampling grid and dynamic range. We test IST on different wavefields with randomly missing traces and compare the data reconstructions with the spectral projected gradient solver and projection onto convex sets. We quantify the reconstructions by a direct comparison of Fourier coefficients between fully sampled and reconstructed wavefields. Taking log10 of Fourier coefficients prior to computing the quality metric deemphasizes the importance of magnitude match while highlighting Fourier coefficient support accuracy, which usually translates into good structural fidelity of reconstructed data. We find that IST performs consistently among all examples, yielding good phase match while performing gentle denoising.

Reconfigurable origami with variable stiffness joints for adaptive robotic locomotion and grasping.

With its compactness and foldability, origami has recently been applied to robotic systems to enable versatile robots and mechanisms while maintaining a low weight and compact form. This work investigates how to generate different motions and shapes for origami by tuning its creases' stiffness on the fly. The stiffness tuning is realized by a composite material made by sandwiching a thermoplastic layer between two shape memory polymer layers. This enables the composite to act as a living hinge, whose stiffness can be actively controlled through Joule heating. To demonstrate our concept, we fabricate an origami module with four variable stiffness joints (VSJs), allowing it to have freely controlled crease stiffnesses across its surface. We characterize the origami module's versatile motion when heating different VSJs with different temperatures. We further use two origami modules to build a two-legged robot that can locomote on the ground with different locomotion gaits. The same robot is also used as an adaptive gripper for grasping tasks. Our work can potentially enable more versatile robotic systems made from origami as well as other mechanical systems with programmable properties (e.g. mechanical metamaterials).This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.

A compact circularly polarized dielectric resonator antenna with MIMO characterizations for UWB applications.

Ultra-wideband (UWB) technology is extensively used in indoor navigation, medical applications, and Internet of Things devices due to its low power consumption and resilience against multipath fading and losses. This paper examines a multiple-input multiple-output (MIMO), circularly polarized (CP) dielectric resonator antenna for UWB systems. Compact form factor, high gain, wideband response, improved port isolation, and high data rates are the major design goals. This arrangement consists of two identical DRAs with self-decoupled orthogonal orientations eliminating the need for extra decoupling structures while achieving an impressive maximum isolation of 43 dB. The corner-edge feeding mechanism of the extended feedline generates two orthogonal E-fields, facilitating circular polarization. Additionally, a printed hook-shaped stub integrated with the ground plane enhances CP performance across the two operating bands without altering the DR structure. Fabrication and testing exhibit an impressive 133 impedance bandwidth (2.5-14 GHz) with high port isolation. For a 3 dB axial ratio reference, the single-element design exhibits axial ratio bandwidths (ARBW) of 1.2 GHz (3.6-4.8 GHz) and 0.8 GHz (9.3-10.1 GHz). Remarkably, the MIMO configuration achieves a single ARBW of 0.5 GHz (3.9-4.4 GHz). Detailed investigations of MIMO performance parameters, including diversity gain, envelope correlation coefficient, channel capacity loss, and total active reflection coefficient, underscore the design's efficacy, making it a good choice for UWB wireless applications.

Assessing the Impact of Smartphone Addiction among medical and health faculty students at university of Kirkuk

Background: Modern smartphones have become an integral part of daily life, particularly among medical students who experience significant academic pressure and stress This study aimed to assess the extent of students' impact from smartphone addiction and investigate its association with their demographic characteristics, socio-economic status, and associated risk factors. Methods: A descriptive cross-sectional study design was used in this study. 772 students from all stages of study in the medical faculties of Kirkuk University. using Smartphone Addiction Scale (SAS), Nordic questionnaires for the analysis of musculoskeletal symptoms, and the severity of digital vision syndrome (DES) was measured using 12 items, The Data was analyzed through Statistical Package for Social Sciences (SPSS) 22. Results: The result of the current study shows that 55.1% were female and the male were 347 (44.9%). the average age of the students was 21.09 ± 1.75. 46.80% of the sample were overweight and obese. around 343(44.4%) sampled are assigned intermittent sleep. while significant relationships are obtained with each of Socio-Economic Status, specialization, using Smartphone in 24hrs, sleeping hours during a day in at least at P<0.05. an overall through global mean of score for the studied domains was assessed in compact form a moderate level, with percentile ranged responses from 5.65 to 80.61 for the studied sample. Conclusion: Our study substantiated that health and medical students are progressing into a state of addiction. no significant difference between males and females when considering of smartphone addiction. The age group most affected was individuals aged 22-23. while the Individuals with moderate to high SES are more susceptibility to addiction. Smartphone use should be limited. To increase awareness and knowledge about the detrimental impacts of smartphone addiction, workshops, courses, and conferences should be held.

Study of different theories of thermoelasticity under the propagation of Rayleigh waves in thermoelastic medium

The present research is on the propagation of Rayleigh waves in a homogenous thermoelastic solid half-space by considering the compact form of six different theories of thermoelasticity. The medium is subjected to an insulated boundary surface that is free from normal stress, tangential stress, and a temperature gradient normal to the surface. After developing a mathematical model, a dispersion equation is obtained with irrational terms. To apply the algebraic method, this equation must be converted into a rational polynomial equation. From this, only those roots are filtered out, which has satisfied both of the above equations for the propagation of waves decaying with depth. With the help of these roots, different characteristics are computed numerically, like phase velocity, attenuation coefficient, and path of particles. Various particular cases are compared graphically by using phase velocity and attenuation coefficient. The elliptic path of surface particles in Rayleigh wave propagation is also presented for the different theories using physical constants of copper material for different depths and thermal conductivity.

Joint Entity and Relation Extraction Using Machine Reading Comprehension for Urdu

Joint Entity and Relation Extraction (JERE) plays an important role in natural language processing (NLP) by identifying names, locations, and the relationships among them from unstructured text. Despite extensive research in languages like English, JERE poses significant challenges in low-resource languages, particularly Urdu, due to limited annotated da-ta and inherent linguistic complexities. In this paper, we propose a novel Machine Reading Comprehension (MRC)-based approach that effectively addresses the JERE task for Urdu, integrating a text encoder and a question-answering module that work synergistically to enhance entity and relationship extraction. We introduce an annotated Urdu JERE dataset and demonstrate how our methodology will significantly contribute to multilingual NLP efforts. We propose an innovative Machine Reading Comprehension (MRC)-based method to tackle JERE in Urdu. This method has two main components: a text encoder and a question answering (QA) module. The text encoder converts Urdu text into a compact vector form, which is then fed into the QA module. The QA module generates answers to queries regarding the desired entities and relationships, producing a sequence of tokens that represent these entities and their interactions. The model is trained to minimize the difference between its predicted answers and the correct ones. Our approach, along with the introduction of an annotated Urdu JERE dataset, significantly advances multilingual NLP and information ex-traction research. The insights gained can be applied to other low-resource languages, aiding in the development of NLP tools and applications for a broader array of languages.

Analytic model for the energy spectrum of the anharmonic oscillator

In a recent work we have proposed an original analytic expression for the partition function of the quartic oscillator. This partition function, which has a simple and compact form with no adjustable parameters, reproduces some key mathematical properties of the exact partition function and provides free energies accurate to a few percent over a wide range of temperatures and coupling constants. In this work, we present the derivation of the energy spectrum of this model. We also generalize our previous study limited to the quartic oscillator to the case of a general anharmonic oscillator. Numerical applications for a potential of the form V(x)=ω22x2+gx2m show that the energy levels are obtained with a relative error of about a few percent, a precision which we consider to be quite satisfactory given the simplicity of the model, the absence of adjustable parameters, and the negligible computational cost.

NEUTROSOPHICATION β-COMPACTNESS

In this study, we first define the concept of neutrosophic β-open set. Then, using this new set definition, we present neutrosophic β-compact and neutrosophic β-closed spaces and examine their properties. Also, we classify these spaces using the concept of neutrosophic filterbase, which is introduced for the first time in this study. And, relationships between these different types and forms of compactness are investigated.

Feline eye-inspired artificial vision for enhanced camouflage breaking under diverse light conditions.

Biologically inspired artificial vision research has led to innovative robotic vision systems with low optical aberration, wide field of view, and compact form factor. However, challenges persist in object detection and recognition against complex backgrounds and varied lighting. Inspired by the feline eye, which features a vertically elongated pupil and tapetum lucidum, this study introduces an artificial vision system designed for superior object detection and recognition in a monocular framework. Using a slit-like elliptical aperture and a patterned metal reflector beneath a hemispherical silicon photodiode array, the system reduces excessive light and enhances photosensitivity. This design achieves clear focus under bright light and enhanced sensitivity in dim conditions. Theoretical and experimental analyses demonstrate the system's ability to filter redundant information and detect camouflaged objects in diverse lighting, representing a substantial advancement in monocular camera technology and the potential of biomimicry in optical innovations.

Numerical analysis of an advanced infrared-based metasurface surface plasmon resonance sensor for COVID-19 detection

The SARS-CoV-2 pandemic has highlighted the critical need for rapid and precise diagnostic methodologies. Conventional testing approaches often exhibit limitations in terms of speed, accessibility, and sensitivity. To address these constraints, we propose an advanced graphene-based biosensing platform for SARS-CoV-2 detection. This sensor integrates advanced nanophotonic principles, metamaterial physics, and two-dimensional material properties to achieve enhanced sensitivity through the detection of refractive index perturbations induced by SARS-CoV-2 biomolecules. Electromagnetic simulations were conducted to optimize the sensor design. The resulting configuration demonstrates a sensitivity of 1800 nmRIU−1 and a detection limit of 0.007 RIU. The sensor exhibits multi-wavelength sensing capabilities at 3.942 μm, 4.018 μm, 4.088 μm, and 4.201 μm, with a high figure of merit of 104.167 RIU−1 and quality factors ranging from 65.766 to 251. 750.The sensor's multilayer architecture, comprising tungsten, graphene, and strontium titanate synergistically enhances both sensitivity and selectivity. Its compact form factor and capacity for real-time analysis render it a promising candidate for point-of-care COVID-19 diagnostics.

Design of fabrication-tolerant meta-atoms for polarization-multiplexed metasurfaces

Metasurfaces can replace bulk optical components in a more compact form factor in applications including communication systems, sensors, and manufacturing technology. However, their design and fabrication is challenging due to competing demands of selecting meta-atoms that simultaneously provide the required amplitude and phase modulation while being robust to fabrication errors. Here, we develop two design heuristics to assist with the down-selection of meta-atoms into sensitivity-informed libraries, based on either selecting meta-atoms with minimal sensitivity or minimizing the relative sensitivities between meta-atoms. We evaluate both methods on a polarization-dependent phase mask and compare the resulting phase and intensity errors.Graphical

Investigating urban morphological drivers of household water use in developing economies: A structural equation model approach

Urban populations are snowballing, increasing household (HH) water consumption. The growing housing density, the expanding infrastructure, and altered land use patterns place increasing pressure on the water supply and usage. This makes it harder for urban HHs to obtain clean water and worsens water scarcity, with infrastructural and environmental implications for highly populated metropolitan areas. This study aims to quantitatively evaluate the impact of urban morphology on household water use in a developing economy using a Structural Equation Model (SEM), specifically within the growing urban centres surrounding Kolkata in South Bengal. The primary hypothesis projects an increase in urban morphological indicators and HH characteristics that significantly affect water use. The findings reveal that increases in urban morphological indicators are associated with a 34.2% decrease in HH water use, highlighting the importance of urban planning strategies that emphasize compact and diverse urban forms. This work highlights new ways of building cities that consider morphological aspects and allow cities to expand in a way that conserves HH water while being resilient to rapid urban change.

Urban functional area building carbon emission reduction driven by three-dimensional compact urban forms’ optimization

Previous optimization approaches with regard to the overall urban form can no longer meet the demand for accurately implementing building energy consumption carbon emission reduction at small spatial scales. This study constructed building energy consumption-oriented urban functional area division method using points of point-of-interest (POI), three-dimensional building and roadway data with urban functional areas as units. The method linked POI to buildings, using building volume as an auxiliary parameter to determine the functional attributes of blocks while taking into account the building operational energy consumption. The residential functional areas, commercial functional areas and industrial functional areas, which account for more than 90% of the total building operation energy consumption and the top three in terms of share, are selected as the analysis objects. Geographic detector was applied to analyze the mechanism of carbon metabolism in the compact spatial patterns of these three functional areas. The case study in Xiamen, China reveals that (1) Three-dimensional building compactness is an important factor influencing building energy consumption(normalized difference vegetation index q-value is 0.227); (2) the difference in energy consumption between different compactness classes in residential and commercial functional areas is significant, while not in industrial functional areas; (3) according to the three-dimensional building compactness optimization path of this study, the building operation energy consumption in central Xiamen City could be optimized to reduce by 7% in 2015. Based on the self-created building energy consumption-oriented functional area division method, it is concluded at the functional areas scale that different types of urban functional zones have different optimization methods for three-dimensional building compactness. Such optimization can save construction resources and achieve double carbon more effectively.

Nonlinear observation of battery microscopic states utilizing adaptive super-twisting sliding-mode observers based on a compact electrochemical-thermal-aging model

Accurate microscopic-state estimation of lithium-ion batteries (LIBs) is a potential candidate for advanced battery management systems. This paper proposes an adaptive super-twisting sliding-mode observer (SMO) for LIB microscopic state perception using a compact and observable electrochemical-thermal-aging model. Considering the physical structure and mathematical model, a simplified single-particle mode with electrolyte is standardized as a compact state-space form after observability analysis. Results show that the compact model is capable of capturing the LIB terminal voltage and temperature with maximum errors of 39.8 mV and 0.2 °C, respectively. After that, the super-twisting SMO is integrated with a neural network-based adaptive law for addressing external disturbances and chattering. Estimation results show that during the majority of cycles, the errors of state of charge, volume-averaged concentration, temperature, and capacity are <3 %, 0.87 kmol/m3, 0.2 °C, and 0.1 Ah, respectively. The side-reaction overpotential of lithium plating prevention can be predicted. Comparable experiments with different observers and hardware-in-the-loop experiments are conducted to explore the estimation accuracy and real-time feasibility of the adaptive observer.

Two-Stage Robust Optimization of Integrated Energy Systems Considering Uncertainty in Carbon Source Load

Integrated Energy Systems (IESs) interconnect various energy networks to achieve coordinated planning and optimized operation among heterogeneous energy subsystems, making them a hot topic in current energy research. However, with the high integration of renewable energy sources, their fluctuation characteristics introduce uncertainties to the entire system, including the corresponding indirect carbon emissions from electricity. To address these issues, this paper constructs a two-stage, three-layer robust optimization operation model for IESs from day-ahead to intra-day. The model analyzes the uncertainties in carbon emission intensity at grid-connected nodes, as well as the uncertainty characteristics of photovoltaic, wind turbine, and cooling, heating, and electricity loads, expressed using polyhedral uncertainty sets. It standardizes the modeling of internal equipment in the IES, introduces carbon emission trading mechanisms, and constructs a low-carbon economic model, transforming the objective function and constraints into a compact form. The column-and-constraint generation algorithm is applied to transform the three-layer model into a single-layer main problem and a two-layer subproblem for iterative solution. The Karush–Kuhn–Tucker (KKT) condition is used to convert the two-layer subproblem into a linear programming model. A case study conducted on a park shows that while the introduction of uncertainty optimization increases system costs and carbon emissions compared to deterministic optimization, the scheduling strategy is more stable, significantly reducing the impact of uncertainties on the system. Moreover, the proposed strategy reduces total costs by 5.03% and carbon emissions by 1.25% compared to scenarios considering only source load uncertainty, fully verifying that the proposed method improves the economic and low-carbon performance of the system.

Structural Basis for Dimerization and Activation of UvrD-family Helicases.

UvrD-family helicases are superfamily 1A motor proteins that function during DNA replication, recombination, repair, and transcription. UvrD family monomers translocate along single stranded (ss) DNA but need to be activated by dimerization to unwind DNA in the absence of force or accessory factors. However, prior structural studies have only revealed monomeric complexes. Here, we report the first structures of a dimeric UvrD-family helicase, Mycobacterium tuberculosis UvrD1, both free and bound to a DNA junction. In each structure, the dimer interface occurs between the 2B subdomains of each subunit. The apo UvrD1 dimer is observed in symmetric compact and extended forms indicating substantial flexibility. This symmetry is broken in the DNA-bound dimer complex with leading and trailing subunits adopting distinct conformations. Biochemical experiments reveal that the E. coli UvrD dimer shares the same 2B-2B interface. In contrast to the dimeric structures, an inactive, auto-inhibited UvrD1 DNA-bound monomer structure reveals 2B subdomain-DNA contacts that are likely inhibitory. The major re-orientation of the 2B subdomains that occurs upon UvrD1 dimerization prevents these duplex DNA interactions, thus relieving the auto-inhibition. These structures reveal that the 2B subdomain serves a major regulatory role rather than participating directly in DNA unwinding.

Legal Perspectives on New Urban Quarters in Germany: Living the Dream of the Compact City?

The ‘leitmotif’ of the compact city has become a widely embraced template for sustainable urban development. Particularly infill and redevelopment areas, as well as many planned new settlements, have been built following the planning principles of urban compaction. Numerous positive effects are attributed to high-density settlements such as more efficient use of infrastructure and less reliance on automobile travel. Planning law and policies, in Germany as well as other countries around the world, regularly strive to advance high-density developments, but it is by no means clear whether the prescribed densities in planning policies actually lead to vibrant and healthy places which fulfill the expectations of their inhabitants with regards to their quality of life. The study aims to analyze the relation between binding land-use plans in Germany and individual perceptions of urban density through a case study-based survey. This paper contributes to providing new information on achieving compact urban form and quality of life in new urban quarters by analyzing the change of densities over the past three decades in ‘large’ urban developments across Germany, by an in-depth assessment of planned and built densities within an archetypal urban extension and finally by contrasting these ‘objective’ figures and findings with the ‘subjective’ feelings of inhabitants. For sources of information, this paper draws from literature, surveys and empirical analyses as well as desktop-studies.