Planar Pattern Research Articles

Understanding the pattern and mechanism of spatial concentration of urban land use, population and economic activities: a case study in Wuhan, China

ABSTRACT Quantifying the aggregation patterns of urban population, economic activities, and land use are essential for understanding compact development, but little is known about the difference among the distribution characteristics and how the built environment influences urban aggregation. In this study, five elements are collected in Wuhan, China, namely population density, floor area ratio, business POIs, road network and built-up area as the representative of urban population, economic activities and land use. An inverse S-shape function is employed to fit the elements’ macro distribution. An aggregation degree index is proposed to measure the aggregation level of urban elements. The kernel density estimation is used to identify the aggregation patterns. The spatial regression model is used to identify the built environment factors influencing the spatial distribution of urban elements. Results indicates that all urban elements decay outward from the city center in an inverse S-shape manner. The business Point-of-Interest (POI) density and population density are highly aggregated; floor area ratio and road density are moderately aggregated, whereas the built-up density is poorly aggregated. Three types of spatial aggregation patterns are identified: a point-shaped pattern, an axial pattern and a planar pattern. The spatial regression modeling shows that the built environment is associated with the distribution of the urban population, economic activities and land use. Destination accessibility factors, transit accessibility factors and land use diversity factors shape the distribution of the business POI density, floor area ratio and road density. Design factors are positively associated with population density, floor area ratio and built-up density. Future planning should consider the varying spatial concentration of urban population, economic activities and land use as well as their relationships with built environment attributes. Results of this study will provide a systematic understanding of aggregation of urban land use, population, and economic activities in megacities as well as some suggestions for planning and compact development.

A compact ultra‐wideband receiving antenna for monitoring applications

AbstractIn this paper, a compact ultra‐wideband receiving antenna is proposed. It consists of a top loaded planar monopole and a circular ground plane. This design combines various techniques such as the comb shaped top loading and the integrated lumped elements to effectively reduce the antenna size, while keeping a wide bandwidth and a reasonable realized gain. The proposed antenna operates across a wide frequency range from 20 to 8 GHz (for S11 <−6 dB), occupies a compact volume of 500 × 500 × 340 mm3 (0.033λ0 × 0.033 λ0 × 0.023 λ0 at 20 MHz) and has a stable omnidirectional radiation pattern in azimuth plane from 20 to 6 GHz. Simulations and measurements are conducted to validate the antenna performance. It is demonstrated that this antenna is well suited to a variety of wideband radio frequency receivers for monitoring use.

Morphological study of the rainbow scattering of protons by graphene.

We have studied metamorphoses of the angular rainbow pattern generated by classical rainbow scattering of protons by graphene. To analyze the rainbow pattern, a morphological method was developed. It focuses on the shape of the rainbow pattern rather than on the exact position of rainbow lines or the particle count. It comprises elements of the catastrophe theory, which provides a local model of the rainbow pattern and the reduced potential and an index theory of algebraic topology that allows the evolution of the rainbow pattern to be linked with bifurcations of critical points of the reduced potential. The obtained insight is summarized into five principles that allow an experimentalist to sketch a qualitatively correct rainbow pattern in the impact parameter plane and the distribution of the reduced potential critical points, just by observing the evolution of the angular rainbows. The morphological method should be applicable for the analysis of all structurally stable patterns in nature.

Conformal screen printed graphene 4 × 4 wideband MIMO antenna on flexible substrate for 5G communication and IoT applications

Screen-printed graphene is integrated with multiple-input multiple-output (MIMO) technology to conquer the most concerned surge in electronic waste caused by the mass deployment of Internet of things (IoT) applications. A flexible MIMO antenna is implemented with simple fabrication process suitable for large-scale production by screen printing graphene highly conductive ink on paper substrate, ensuring high-speed 5G mass data wireless transmission without damaging the ecological environment. This environmental-friendly, low-cost, flexible and conformal MIMO antenna with orthogonal polarization diversity employs co-planar waveguide feed and planar pattern for achieving high space utilization and better integration in most scenarios, for instance, body centric networks and monitoring systems. Excellent performance has been achieved due to the high conductivity of the graphene: the fabricated antenna exhibits an average sheet resistance of . The bandwidth of the antenna ranges from (53.71% fractional bandwidth), covering long term evolution, sub-6 GHz mobile communication networks, 2.5 and 3.5 GHz WiMAX, and 2.4 and 3.6 GHz WLAN. Within this range, the antenna exhibits effective radiation, also its envelope correlation coefficient remains below , manifesting outstanding signal transmission quality in a variety of wireless networks. This work illustrates a novel aggregation of MIMO technology and graphene printing electronics, enabling cheap accessible and green MIMO antennas to be massively integrated in IoT applications.

A Low-Profile Ultrawideband Antenna Based on Flexible Graphite Films for On-Body Wearable Applications

This paper presents a low-profile ultrawideband antenna for on-body wearable applications. The proposed antenna is based on highly conductive flexible graphite films (FGF) and polyimide (PI) substrate, which exhibits good benefits such as flexibility, light weight and corrosion resistance compared with traditional materials. By introducing flaring ground and an arrow-shaped slot, better impedance matching is achieved. The wearable antenna achieves a bandwidth of 122% from 0.34 GHz to 1.4 GHz, with a reflection coefficient of less than −10 dB, while exhibiting an omnidirectional pattern in the horizontal plane. To validate the proposed design, the wearable antenna with a profile of ~0.1 mm was fabricated and measured. The measured results are in good agreement with simulated ones, which indicates a suitable candidate for on-body wearable devices.

A Miniaturized Broadband and High Gain Planar Vivaldi Antenna for Future Wireless Communication Applications

This paper presents a new miniaturized planar Vivaldi antenna (PVA) design. The proposed antenna structure consists of an aperture tapered profile and cavity stub fed with a simple 50 Ω strip line feeding network. The designed PVA offers versatile advantages, including the miniaturized size and simple design, and exhibited an outstanding performance compared to the latest reported literature. The antenna occupies a minimal space with an electrical size of 0.92λ0 × 0.64λ0 × 0.03λ0. The antenna achieves an excellent relative impedance bandwidth 117.25% at 10 dB return loss, peak realized gain of 10.9 dBi, and an excellent radiation efficiency of 95% at the specific resonances. The antenna’s optimal features, that is, broadband, high gain, and radiation efficiency, are achieved with efficient grooves based approach. Besides, the proposed antenna results are also analyzed in the time domain, which shows the excellent group delay performance <2 ns in the operational band. The proposed antenna exhibited a stable far-field radiation pattern in orthogonal planes and strong distribution of current at multiple resonances. Simulation and the measured result show a good agreement. The proposed antenna has achieved optimal performance and is suitable for future wireless communication applications.

Compressive Buckling Fabrication of 3D Cell-Laden Microstructures.

Tissue architecture is a prerequisite for its biological functions. Recapitulating the three‐dimensional (3D) tissue structure represents one of the biggest challenges in tissue engineering. Two‐dimensional (2D) tissue fabrication methods are currently in the main stage for tissue engineering and disease modeling. However, due to their planar nature, the created models only represent very limited out‐of‐plane tissue structure. Here compressive buckling principle is harnessed to create 3D biomimetic cell‐laden microstructures from microfabricated planar patterns. This method allows out‐of‐plane delivery of cells and extracellular matrix patterns with high spatial precision. As a proof of principle, a variety of polymeric 3D miniature structures including a box, an octopus, a pyramid, and continuous waves are fabricated. A mineralized bone tissue model with spatially distributed cell‐laden lacunae structures is fabricated to demonstrate the fabrication power of the method. It is expected that this novel approach will help to significantly expand the utility of the established 2D fabrication techniques for 3D tissue fabrication. Given the widespread of 2D fabrication methods in biomedical research and the high demand for biomimetic 3D structures, this method is expected to bridge the gap between 2D and 3D tissue fabrication and open up new possibilities in tissue engineering and regenerative medicine.

Runners Adapt Different Lower-Limb Movement Patterns With Respect to Different Speeds and Downhill Slopes.

The aim of this study was to investigate the influence of slope and speed on lower-limb kinematics and energy cost of running. Six well-trained runners (VO2max 72 ± 6 mL·kg−1·min−1) were recruited for the study and performed (1) VO2max and energy cost tests and (2) an experimental running protocol at two speeds, 12 km·h−1 and a speed corresponding to 80% of VO2max (V80, 15.8 ± 1.3 km·h−1) on three different slopes (0°, −5°, and −10°), totaling six 5-min workload conditions. The workload conditions were randomly ordered and performed continuously. The tests lasted 30 min in total. All testing was performed on a large treadmill (3 × 5 m) that offered control over both speed and slope. Three-dimensional kinematic data of the right lower limb were captured during the experimental running protocol using eight infrared cameras with a sampling frequency of 150 Hz. Running kinematics were calculated using a lower body model and inverse kinematics approach. The generic model contained three, one, and two degrees of freedom at the hip, knee, and ankle joints, respectively. Oxygen uptake was measured throughout the experimental protocol. Maximum hip extension and flexion during the stance phase increased due to higher speed (p < 0.01 and p < 0.01, respectively). Knee extension at the touchdown and maximal knee flexion in the stance phase both increased on steeper downhill slopes (both p < 0.05). Ground contact time (GCT) decreased as the speed increased (p < 0.01) but was unaffected by slope (p = 0.73). Runners modified their hip movement pattern in the sagittal plane in response to changes in speed, whereas they altered their knee movement pattern during the touchdown and stance phases in response to changes in slope. While energy cost of running was unaffected by speed alone (p = 0.379), a shift in energy cost was observed for different speeds as the downhill gradient increased (p < 0.001). Energy cost was lower at V80 than 12 km·h−1 on a −5° slope but worse on a −10° slope. This indicates that higher speeds are more efficient on moderate downhill slopes (−5°), while lower speeds are more efficient on steeper downhill slopes (−10°).

Radial nerve palsy following humeral shaft fracture: a theoretical PNF rehabilitation approach for tendon and nerve transfers

ABSTRACT Background Humerus fracture-induced radial nerve injury can create severe and permanent disabilities. Purpose Surgical management often relies on either tendon or nerve transfer. Regardless of which procedure is selected, physical therapists are challenged to restore functional outcomes without jeopardizing repair healing. Through synergistic, multi planar upper extremity movement patterns, neuromuscular irradiation, or overflow, and neuroplasticity, proprioceptive neuromuscular facilitation (PNF) may improve strength, range of motion and tone. Methods After reviewing the literature, a five phase PNF-based treatment approach is proposed with timing differences based on the selected procedure. Findings Phase I (2 or 4 weeks pre-surgery for tendon or nerve transfer, respectively) consists of comprehensive patient education; Phase II (4–6 or 1–2 weeks post-surgery for tendon or nerve transfer, respectively) explores variable duration peripheral and central nervous system motor learning during isometric activation to enhance central neuroplasticity; Phase III (7–12 or 3–20 weeks post-surgery for tendon or nerve transfer, respectively) incorporates low-intensity motor control including contralateral isotonic upper extremity loading to maximize overflow and neuroplastic effects; Phase IV (13–26 or 21–52 weeks post-surgery for tendon or nerve transfer, respectively) adds high-intensity strength and motor control using ipsilateral isotonic upper extremity loading to maximize overflow and neuroplastic effects. Phase V (27–52 or 53–78 weeks post-surgery for tendon or nerve transfer, respectively) progresses to more activity of daily living, vocational, or sport-specific training with higher intensity strength and motor control tasks. Conclusions Through manually guided synergistic, multi planar movement, overflow, and neuroplasticity, a PNF treatment approach may optimize neuromuscular recovery. Validation strategies to confirm clinical treatment efficacy are discussed.

Nanoscale 3D Printing of Quantum Dots on Paper

Nanoscale integration is difficult on rough surfaces despite their ubiquity and usefulness. Paper is an emerging material system because it is renewable, flexible, and lightweight. However, owing to the rough surface of paper, it is difficult to use conventional nanoscale integration methods. Herein, nanoscale printing of CdSe/ZnS quantum dots on paper using a 3D printing method with surface adaptive control of the femtoliter meniscus is demonstrated. The approach allows the direct integration of light‐emitting materials on the intact surface of paper with nanoscale lateral confinement. The 3D‐printed nanostructures can be treated as a planar pattern of the nanoscale dots when viewed from the top. The individually addressable nature of the 3D printing method enables the equalization of the printed heights, which is essential for practical use in general planar systems. This method can be used in many areas that require paper such as paper electronics, security printing, biomedical engineering, and possibly other material systems with rough surfaces.

Video-Rate Identification of High-Capacity Low-Cost Tags in the Terahertz Domain.

In this article, we report on video-rate identification of very low-cost tags in the terahertz (THz) domain. Contrary to barcodes, Radio Frequency Identification (RFID) tags, or even chipless RFID tags, operate in the Ultra-Wide Band (UWB). These THz labels are not based on a planar surface pattern but are instead embedded, thus hidden, in the volume of the product to identify. The tag is entirely made of dielectric materials and is based on a 1D photonic bandgap structure, made of a quasi-periodic stack of two different polyethylene-based materials presenting different refractive indices. The thickness of each layer is of the order of the THz wavelength, leading to an overall tag thickness in the millimetre range. More particularly, we show in this article that the binary information coded within these tags can be rapidly and reliably identified using a commercial terahertz Time Domain Spectroscopy (THz-TDS) system as a reader. More precisely, a bit error rate smaller than 1% is experimentally reached for a reading duration as short as a few tens of milliseconds on an 8 bits (~40 bits/cm2) THID tag. The performance limits of such a tag structure are explored in terms of both dielectric material properties (losses) and angular acceptance. Finally, realistic coding capacities of about 60 bits (~300 bits/cm2) can be envisaged with such tags.

Analysis of the Spatial Distribution Pattern of the Urban Landscape in the Central Plains under the Influence of Multiscale and Multilevel Morphological Geomorphology

This paper presents an in-depth analysis and research on the spatial distribution pattern of the urban landscape in the Central Plains digital landscape form and proposes an optimization scheme. Based on the basic theories of systematics and complexity, this paper analyzes the self-similar characteristics of urban morphology, establishes the concept of schema, and constructs a multiscale and multilevel morphological map research framework by drawing on the “planar pattern” morphological analysis method of the school and the “matrix, patch, and corridor” spatial expression model of landscape ecology. The framework of morphological map research at multiple scales has been established, and the theory and method of describing, understanding, judging, and analyzing morphological evolution have been formed. Cities have self-similarity at different scales, and urban evolution is a process of recursion from small-scale hierarchy to large-scale hierarchy, and hierarchy is a phenomenon presented by the natural evolution of cities. After any morphological process is completed, it can only be transformed into the other two ways, so the static morphological description can be transformed into dynamic morphological process analysis.

High-accurate camera calibration in three-dimensional visual displacement measurements based on ordinary planar pattern and analytical distortion model

Camera calibration is crucial for geometric vision-based three-dimensional (3D) deformation measurement tasks. Among existing calibration techniques, the one based on planar targets has attracted much attention in the community due to its flexibility and reliability. Our study proposes a calibration technique to obtain high-accuracy internal and external parameters based on low-cost ordinary planar patterns. The proposed method determines the optimal internal parameters for each camera by refining 3D coordinates of planar control points, where an analytic model of optics distortion is presented to enable lens distortion to be corrected directly in subsequent external calibration and underlying 3D reconstruction. External parameters are estimated by minimizing a bundle adjustment framework, which is carefully designed based on the proposed distortion correction model and depth parameterization. In contrast to the existing techniques, the proposed method is capable of obtaining a high-accuracy calibration with ordinary targets rather than the well-designed and fabricated ones. We experimented the proposed method with a calibration performance analysis and a displacement measurement; both results demonstrated the accuracy and robustness.

Rotationally invariant ring-shaped liquid crystal structures between two substrates with different photoalignment

Planar patterned photoalignment can be used to align liquid crystals (LCs) in any azimuthal orientation. Using different patterns on both substrates, we fabricated and analyzed complex three-dimensional LC structures. We developed four configurations in which planar patterns with rotational symmetry are defined at each substrate. All four configurations generate a ring-shaped region in the bulk of the sample where the LC aligns vertically. The director configurations are calculated using numerical simulations and are verified by comparing the simulated optical transmission to the measured microscopy images. The vertical alignment in the bulk of the cell makes it possible to use this configuration as a waveguide, as demonstrated by a waveguide mode simulation.

Subset-based stereo calibration method optimizing triangulation accuracy.

Calibration of vision systems is essential for performing measurement in real world coordinates. For stereo vision, one performs stereo calibration, the results of which are used for 3D reconstruction of points imaged in the two cameras. A common and flexible technique for such calibration is based on collection and processing pairs of images of a planar chessboard calibration pattern. The inherent weakness of this approach lies in its reliance on the random nature of data collection, which might lead to better or worse calibration results, depending on the collected set of image pairs. In this paper, a subset-based approach to camera and stereo calibration, along with its implementation based on OpenCV, is presented. It utilizes a series of calibration runs based on randomly chosen subsets from the global set of image pairs, with subsequent evaluation of metrics based on triangulating the features in each image pair. The proposed method is evaluated on a collected set of chessboard image pairs obtained with two identical industrial cameras. To highlight the capabilities of the method to select the best-performing calibration parameters, a principal component analysis and clustering of the transformed data was performed, based on the set of metric measurements per each calibration run.

Comparison of skeletal and dentoalveolar changes between pure bone-borne and hybrid tooth-borne and bone-borne maxillary rapid palatal expanders using cone-beam computed tomography

Objectives: The objectives of the study were to compare the skeletal, dentoalveolar, and periodontal changes between two types of microimplant-assisted rapid maxillary expansion appliances: The bone-anchored maxillary expanders (BAME) and the tooth-bone-anchored maxillary skeletal expander (MSE). Materials and Methods: Thirty-four patients with a transverse maxillary deficiency were divided into two groups; the first group (16 patients, average age 14.9 years) was treated with the MSE appliance, and the second group (18 patients, average age 13.8 years) was treated with the BAME appliance. Cone-beam computed tomography scans were taken at pre-treatment (T1) and immediately post-expansion (T2) to measure the changes in midpalatal suture opening, total expansion (TE), alveolar bone bending, dental tipping (DT), and buccal bone thickness. Data were analyzed using paired t-test and two-sample t-test. Results: Midpalatal suture separation was found in 100% of the patients in both groups. The TE at the first molar was 5.9 mm in the MSE group and 4.7 mm in the BAME group. The skeletal contributions were 56% and 83% of TE for the MSE and BAME groups, respectively. Significantly less dental buccal tipping and buccal bone loss were found with the BAME group. The midpalatal suture in both groups exhibited a parallel opening pattern in the axial plane. Conclusion: The use of BAME appliance resulted in greater skeletal effects, less dental tipping, and less buccal bone reduction compared to MSE appliance (immediately after maxillary expansion).

Broadband dual‐polarized crossed‐dipole antenna with tapered integrated balun for base‐station applications

A ± 45° dual-polarized dipole antenna with low profile and stable radiation pattern over a wide operating band for base station is proposed. The antenna is formed by two polygon-shaped dipoles and a shaped metallic reflector. Two baluns with tapered structure are used to excite the dipoles for dual-polarized radiation and enhancing the impedance matching and bandwidth, while the shaped-reflector is used to obtain stable radiation pattern in the horizontal plane during a wide frequency band. The design principles of crossed dipoles, baluns and reflector is described in detail. The proposed antenna achieves wide impedance bandwidth of 67% for VSWR<1.5, and high-isolation better than 31 dB over the operating band. In addition, the 3 dB beamwidth in the horizontal plane of the antenna is stabilized within the range of 66.3° ± 2.8°. These performances make the presented antenna applicable for mobile communications.

Spine and pelvis coordination variability in rowers with and without chronic low back pain during rowing

The aim of this study was to compare the spine-pelvis coordination and coordination variability (CV) during rowing in elite rowers with and without chronic low back pain (CLBP). Fourteen professional rowers (6 healthy and 8 with CLBP) participated in this study. 3D kinematic of upper trunk (UT), lower trunk (LT), lower back (LB), and pelvis segments during ergometer rowing at 70% and 100% of peak power were captured. The adjacent segments’ coordination and CV were calculated using modified vector coding method. The results showed that segments’ range of motion increased in both groups with increasing intensity, especially in CLBP rowers. CLBP rowers showed significantly lower: LT dominancy in LT/LB coordination at both intensities; anti-phase pattern in LB/Pelvis coordination at 100% intensity; UT/LT CV in early recovery, and significantly higher LB/Pelvis CV in final recovery and catch position (p < 0.05). Moreover, both groups showed significantly lower UT dominancy for UT/LT coordination in sagittal plane; higher anti-phase pattern in frontal plane; lower UT/LT CV in sagittal plane, lower LT/LB CV in sagittal and transverse plane, lower LB/Pelvis CV in frontal plane in trunk preparation phase, and a lower UT/LT CV in frontal plane for acceleration phase at 100% versus 70% intensity. In conclusion rowers with CLBP cannot adapt their coordination pattern and its variability with increase in intensity, and the movement in the kinematic chain from pelvis to UT stops in spine-pelvic junction. These findings have practical implications in designing coaching and rehabilitation strategies to facilitate performance and prevent injuries.

A novel quadband ultra miniaturized planar antenna with metallic vias and defected ground structure for portable devices

A novel heart-shaped monopole antenna used in wireless portable communication devices is proposed and discussed in this paper. The antenna has a radiant patch surface area of 28.504 mm2, the physical size of 15 × 12.5 × 1 mm3, and electrical dimensions of 0.095λ0 × 0.079λ0 × 0.006λ0, where λ0 denotes the wavelength of the free space at 1.89 GHz. Its prototype is printed on FR4 HTG-175, having a permittivity of 4.2 and a loss tangent of 0.019 at 1 GHz. The partial ground plane and two metallic vias connecting two open-ended branches of the slitted radiating patch to a parasitic conductor element results in about 98% miniaturization of the active patch area, as compared to the conventional antenna. The proposed antenna exhibits nearly an omnidirectional pattern in the elevation plane with a maximum radiation efficiency of 82.78% at 3.99 GHz, while a peak gain of 4.7 dBi is obtained at 6.5 GHz. The measured -6 dB impedance bandwidths demonstrate that the proposed quadband antenna operates in all the frequency bands of mobile telecommunication standards (2G/3G/4G/5G) and other applications, including WLAN, WiMAX, ISM, meteorological services, IEEE 802.11y, and C-band satellite communications. This antenna is easy to manufacture and can be used in most portable devices as a compact internal antenna. After simulating the modeled antenna using HFSS, a prototype was experimentally tested, and the measured results were compared with the data obtained by simulation. The parameters analyzed are return loss, bandwidth, and gain on all frequency bands. The fabricated prototype guarantees a minimum -10 dB bandwidth of 110 MHz and a maximum return loss of -12.2 dB, despite its low radiation efficiency of 21.43 % in the lower band dedicated to GSM applications. Furthermore, the proposed antenna operates as a narrowband and wideband.

Walking lower extremity biomechanics of adolescents with autism spectrum disorder

Although the literature indicates children with autism spectrum disorder (ASD) walk at slower speeds and altered kinematics compared to neurotypical controls, no research has examined walking at matched speeds. This study examined biomechanical differences between adolescents with ASD and matched (age, sex, and body mass index) neurotypical controls. Lower extremity biomechanics of seventeen adolescents with ASD and seventeen controls were compared at matched speeds: self-selected and a standardized 1.3 m/s. Controls exhibited greater eversion angles and hip abduction moments compared to those with ASD. This study found adolescents, which may have a more mature gait than young children, walk with a similar pattern in the propulsive plane (i.e. sagittal) as neurotypical controls, but with alterations in the supportive plane (i.e. frontal).