Position Mismatch Research Articles

Wavelet‐Forward Family Enabling Stitching‐Free Full‐Field Fourier Ptychographic Microscopy

AbstractFourier ptychographic microscopy (FPM) breaks through the resolution limitations of conventional optical systems, which offer a full‐field view and high resolution without additional mechanical scanning. However, conventional image‐domain optimizations require trade‐offs between correction efficacy, data redundancy, and reconstruction accuracy. Furthermore, the existing linear time‐invariant model for actual nonlinear, time‐varying optical systems leads to forward model mismatch, complicating the corrections of the vignetting effect. To overcome these challenges and achieve stitching‐free FPM, a family of forward wavelet‐transform models (WL‐FPM) is proposed. WL‐FPM employs the reversibility of the wavelet transform for high‐fidelity reconstruction in the multiscale feature domain. The wavelet loss function is updated in each iteration, and non‐convex optimization is solved by complex back diffraction. WL‐FPM offers stitching‐free, high‐resolution, and robust reconstruction under various challenging conditions, including vignetting effects, LED position mismatch, intensity fluctuations, and high‐level noise environments, which outperform conventional FPM methods. Under a 4X objective with NA 0.1, WL‐FPM achieves a 435‐nm resolution and stitching‐free full‐field reconstruction of a 3.328 × 3.328 mm2 pathological section with distinct subcellular organelles. In live cell imaging, it provides a full‐field observation with distinct lipids in a single cell. A large number of simulation and experimental results demonstrate its potential for biomedical applications.

To Stick or Not to Stick? Studying the Impact of Offset Recovery Techniques During Mid-Air Interactions.

During mid-air interactions, common approaches (such as the god-object method) typically rely on visually constraining the user's avatar to avoid visual interpenetrations with the virtual environment in the absence of kinesthetic feedback. This paper explores two methods which influence how the position mismatch (positional offset) between users' real and virtual hands is recovered when releasing the contact with virtual objects. The first method (sticky) constrains the user's virtual hand until the mismatch is recovered, while the second method (unsticky) employs an adaptive offset recovery method. In the first study, we explored the effect of positional offset and of motion alteration on users' behavioral adjustments and users' perception. In a second study, we evaluated variations in the sense of embodiment and the preference between the two control laws. Overall, both methods presented similar results in terms of performance and accuracy, yet, positional offsets strongly impacted motion profiles and users' performance. Both methods also resulted in comparable levels of embodiment. Finally, participants usually expressed strong preferences toward one of the two methods, but these choices were individual-specific and did not appear to be correlated solely with characteristics external to the individuals. Taken together, these results highlight the relevance of exploring the customization of motion control algorithms for avatars.

A high‐power and high‐efficiency low‐profile aperture converter array

AbstractFor a phased‐array antenna system, position mismatches in spacing distances between source's output and antenna arrays’ input ports are common. At present, flexible radiofrequency cables are always utilized to electrically connect those two parts, which will result in the reduced integration. To tackle this problem, a low‐profile aperture converter array (ACA) is first proposed, which is applied between a microwave source and antenna arrays. Each stripline‐structured channel of the ACA is composed of the signal lines with different routing shapes to achieve nearly the same phase shift. In this study, a high‐power and high‐efficiency 16‐channel ACA is designed, fabricated and measured at X‐band. Experimental results show that it meets the requirement of 5‐kW pulse wave input, and the power transfer efficiency of each channel is more than 93.8%. Furthermore, its profile is only 0.42 at 9 GHz, which is favorable to transforming the integration of the whole system.

An Adult with Acute Breathlessness and Unilateral Diffuse Alveolar Opacities

Abstract Cardiogenic pulmonary edema is typically bilateral and results from the accumulation of excessive fluid in the interstitial and alveolar spaces of the lungs caused by left ventricular failure. Cardiogenic unilateral pulmonary edema (CUPE) is uncommon and most often documented in severe mitral regurgitation. CUPE in other cardiac diseases such as coronary artery disease is rare and occasionally associated with prolonged lateral decubitus position or vascular perfusion mismatch between lungs either congenital such as pulmonary artery agenesis or acquired due to preexisting lung conditions such as compensatory emphysema following lobectomy. The radiologic opacities of CUPE does not have characteristic features as described with bilateral pulmonary edema. The possibility of CUPE is often not considered initially as its clinical/radiologic features often resemble or are mistaken as pneumonia resulting in diagnostic delay and higher mortality.

L1 slope: an overlooked spinal parameter.

Lumbar lordosis can be divided into two parts by a horizontal line, creating the L1 slope and the sacral slope. Despite being a major spinopelvic parameter, the L1slope (L1S) is rarely reported. However, there is some evidence that L1S is a relatively constant parameter. This study aimed to analyze the L1 slope and its relationships with other spinopelvic parameters. Standing lateral lumbosacral x-ray radiographies of 76 patients with low back pain and CT scans of 116 asymptomatic subjects were evaluated for spinal and spinopelvic parameters including L1 slope (L1S). The x-ray and CT groups were divided into subgroups according to mean sacral slope (SS) or pelvic incidence (PI) values. The mean values of the spinopelvic parameters and the correlations between them were investigated and compared. L1S was 19.70 and 18.15 in low SS and high SS subgroups of x-ray respectively. L1S was 7.95 and 9.36 in low and high PI subgroups of CT, respectively, and the differences were insignificant statistically. L1S was the only spinal parameter that did not change as SS or PI increased in standing and supine positions. L1S was correlated with lumbar lordosis (LL) proximal lumbar lordosis (PLL) and distal lumbar lordosis (DLL) in both x-ray and CT groups. L1S was also the strongest correlated parameter with pelvic incidence lumbar lordosis mismatch (PI-LL) mismatch in supine position. L1S is a relatively constant parameter and is around 16°-18° and 8°-9° in the standing and supine positions, respectively. It was significantly correlated with LL, PLL, DLL, and PI-LL. In the standing position it was nearly equal to PLL while this equality was present in low PI subgroups of CT. There is strong evidence that L1S is significantly correlated with health-related quality of life scores.

One-dimensional photothermal characterization of subsurface interfaces utilizing the virtual wave concept

This work presents one-dimensional photothermal results for estimating subsurface interface parameters using the virtual wave concept. The performed study demonstrates the capability of the virtual wave concept as a feature extraction method for estimating the depth position and thermal mismatch of subsurface interfaces within layered materials. The mathematical relationship between the reflection coefficient of the thermal wave and the signal of the virtual wave is demonstrated for exact one-dimensional solutions. For experimental validation, pulsed thermography in the pulse-echo configuration for different metallic specimens is applied. This method yields a very good estimation of the interfacial parameters for the analyzed samples. In summary, a feasible and fast one-dimensional photothermal evaluation of subsurface interfaces using the virtual wave concept is demonstrated.

Development and validation of allele-specific PCR-based SNP typing in a gene on chromosome D03 conferring resistance to Fusarium wilt race 4 in Upland cotton (Gossypium hirsutum).

Upland cotton (Gossypium hirsutum) is the most important fiber crop for the global textile industry. Fusarium oxysporum f. sp. vasinfectum (FOV) is one of the most destructive soil-borne fungal pathogens in cotton. Among eight pathogenic races and other strains, FOV race 4 (FOV4) is the most virulent race in US cotton production. A single nucleotide polymorphism (SNP) in a glutamate receptor-like gene (GhGLR4.8) on chromosome D03 was previously identified and validated to confer resistance to FOV race 7, and targeted genome sequencing demonstrated that it was also associated with resistance to FOV4. The objective of this study was to develop an easy and convenient PCR-based marker assay. To target the resistance SNP, a forward primer for the SNP with a mismatch in the 3rd position was designed for both the resistance (R) and susceptibility (S) alleles, respectively, with addition of 20-mer T7 promoter primer to the 5' end of the forward primer for the R allele. The two forward primers, in combination with each of five common reverse primers, were targeted to amplify amplicons of 50-260bp in size with R and S alleles differing in 20bp. Results showed that each of three common reverse primers in combination with the two forward primers produced polymorphic markers between R and S plants that were consistent with the targeted genome sequencing results. The polymorphism was distinctly resolved using both polyacrylamide and agarose gel electrophoreses. In addition, a sequence comparative analysis between the resistance gene and homologous sequences in sequenced tetraploid and diploid A and D genome species showed that none of the species possessed the resistance gene allele, suggesting its recent origin from a natural point mutation. The allele-specific PCR-based SNP typing method based on a three-primer combination provides a fast and convenient marker-assisted selection method to search and select for FOV4-resistant Upland cotton.

Flexible and broadband colloidal quantum dots photodiode array for pixel-level X-ray to near-infrared image fusion

Combining information from multispectral images into a fused image is informative and beneficial for human or machine perception. Currently, multiple photodetectors with different response bands are used, which require complicated algorithms and systems to solve the pixel and position mismatch problem. An ideal solution would be pixel-level multispectral image fusion, which involves multispectral image using the same photodetector and circumventing the mismatch problem. Here we presented the potential of pixel-level multispectral image fusion utilizing colloidal quantum dots photodiode array, with a broadband response range from X-ray to near infrared and excellent tolerance for bending and X-ray irradiation. The colloidal quantum dots photodiode array showed a specific detectivity exceeding 1012 Jones in visible and near infrared range and a favorable volume sensitivity of approximately 2 × 105 μC Gy−1 cm−3 for X-ray irradiation. To showcase the advantages of pixel-level multispectral image fusion, we imaged a capsule enfolding an iron wire and soft plastic, successfully revealing internal information through an X-ray to near infrared fused image.

System error estimation for sensor network with integrated sensing and communication application

The integrated sensing and communication base station can perform both communication and sensing tasks simultaneously. The key premise of accurate localization and tracking of targets is sensor registration process. If system errors of multi-sensor system are not corrected properly, it can lead to significant sensing errors and reduce the overall system performance. In this paper, we propose a system error estimation method for a 3-dimensional asynchronous base station network to achieve satisfactory localization and tracking performance. Specifically, by making use of the priori information of the cooperative targets, we propose to minimize the sum of squares of the position mismatch errors of the targets, this leads to a nonlinear error estimation model for the system errors. To handle the high nonlinearity and ensure fast convergence of online registration, an efficient inexact block coordinate descent optimization algorithm incorporating the proximal method is proposed. The algorithm divides the estimation problem into a linear least square subproblem and several quadratic constrained quadratic program subproblems, enabling different kinds of system errors to be alternatively updated. Finally, the effectiveness and feasibility of the proposed estimation algorithm are demonstrated through numerical simulation.

Unraveling Optical and Electrical Gains of Perovskite Solar Cells with an Antireflective and Energetic Cascade Electron Transport Layer

Electron transport layers (ETLs) are imperative in n-i-p structured perovskite solar cells (PSCs) because of their capability to affect light propagation, electron extraction, and perovskite crystallization, and any mismatch of optical constants, band position, and surface potential between the ETLs and the perovskites can cause unintentional optical and electrical losses. Herein, an antireflective and energetic cascade bilayer ETL with ubiquitously used SnO2 and TiO2 was constructed at 150 °C for PSCs, and the in-depth mechanism for performance improvement was systematically unraveled. It was revealed that the construction of an ETL with gradually increasing refractive indices can circumvent light reflection loss, resulting in enhanced photocurrent. The combined ETL forms an energetic cascade to promote electronic conductivity and facilitate electron extraction with reduced energy loss. Moreover, topologic perovskite growth with improved crystallinity and vertical orientation was preferred owing to the relative dewetting behavior, leading to reduced defect states and enhanced carrier mobility in the perovskite layer.

Left and Right in Space and Politics

The terms left and right can refer to spatial or political orientations. We hypothesized that a match (vs. mismatch) of spatial position and political orientation would lead to more positive political judgments. In three experiments, German participants (total N = 517) evaluated statements from the political left-wing and right-wing spectrums as well as German political parties presented either on the left or on the right side of their screens. When statements were presented on the left, politically left statements as well as left-wing parties were evaluated more favorably than when these statements were presented on the right. Conversely, politically right statements and right-wing parties were evaluated more favorably when the statements were presented on the right versus left side of the screen. Cultural conservatism, need for cognitive closure, and openness to experience were assessed but did not mediate these effects. We discuss theoretical and practical implications of the results.

System design and error correction of simultaneous phase-shifting point-diffraction interferometer for dynamic wavefront detection with 400 mm aperture.

In this paper, a simultaneous phase-shifting point-diffraction interferometer (SPS-PDI) at632.8nm is designed with the assistance of an off-axis parabolic mirror (OAPM), through which the dynamic wavefront with 400mm aperture can be detected. In the system, a polarization point-diffraction plate (P-PDP) is developed to modulate the polarization states of the reference light and the test light through a simultaneous phase-shifting system based on a chessboard phase grating and a retarder array, and four phase-shifting interferograms can be acquired to realize dynamic detection. Furthermore, the circular carrier squeezing interferometry (CCSI) is proposed to suppress the phase errors generated by position mismatch, intensity distortion, and phase-shift error. The detection result of the SPS-PDI is consistent with the 4D PhaseCam6000 dynamic interferometer. The difference of the peak-to-valley (PV) and root-mean-square (RMS) values are only 0.04λ and 0.008λ. Additionally, the capacity to detect dynamic wavefront is good.

Detection and Mitigation of GNSS Spoofing Attacks in Maritime Environments Using a Genetic Algorithm

Due to the high reliance of daily activities on the Global Navigation Satellite System (GNSS), its security is one of the major concerns for research and industry. Most navigation and mobile-driven location-based services use GNSS to render services. Due to the low power and easy access of GNSS signals, these signals are vulnerable to spoofing and other types of attacks. Recently many GNSS spoofing attacks have been identified in road- and maritime-based environments. This study provides a technique to detect and counter the GNSS spoofing attack in the maritime environment. This technique uses the Receiver Autonomous Integrity Monitoring (RAIM) model with Least Square Estimation (LSE) and Proportional Integral Derivative (PID) Control to detect the spoofing attack. The proposed technique is based on the concept of a genetic algorithm and navigation devices, such as inertial sensors and pilot options for the ship. A case study using the AIS dataset and simulation using MATLAB and NS3 is provided to validate the performance of the proposed approach. Nine different voyages from the AIS dataset were considered to check the accuracy and performance of the proposed algorithm. The accuracy of the proposed technique was analyzed using the correctly identified attack. The result shows that the proposed technique identifies spoofing attacks with an average value of 90 percent. For result analysis the considered nine routes were traversed multiple times. Root mean square error is used to calculate the positional mismatch (error rate). Based on the combined results analysis, the average value of RMSE is 0.28. In a best-case scenario, the proposed approach provides an RMSE value of 0.009.

Finite element analysis of the effect of knee movable unicompartmental prosthesis insertion shape and mounting position on stress distribution in the knee joint after replacement

In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.

The Double-Peak Specific Heat in the Two Dimensional J1–J2 3-State Clock Model

By the extensive tensor network algorithms, the J1–J2 3-state clock model is investigated. We focus on the case of J1 > 0, J2 < 0, in which the double-peak structure appears in the curve of the specific heat Cv versus the temperature T. The four parameters \(J_{2} = - 0.2, - 0.8, - 1.4, - 2\) are chosen for the detailed numerical simulation in unit of J1 = 1. The mismatch of peak position between entanglement entropy (EE) and Cv suggests the existence of two Berezinskii–Kosterlitz–Thouless (BKT) phase transitions in case of \(J_{2} = - 0.2, - 0.8\), where the peaks of EE lie inbetween the double peaks of Cv. In the case of J2 = −1.4, the first-peak temperature of Cv and of EE are very close. With further increasing of |J2|, the sequence of the first peak swaps, i.e., the first peak of EE arises at a lower temperature than of Cv. We believe that there is a critical |J2|, above which the first peak of Cv does not correspond to the BKT phase transition. The location offset of the second peak between EE and Cv becomes smaller with |J2| increasing. In addition, the double-peak structure of the specific heat still holds when |J2| is large enough.

Boundary conditions for molecular simulations of isolated elastic defects. Case study: The ⟨111⟩ screw dislocation in bcc W

A new set of boundary conditions is proposed for molecular simulations of isolated elastic defects such as dislocations and cracks. The case study of the ⟨111⟩ screw dislocation in body centered cubic (bcc) tungsten, modeled via a phenomenological, n-body cohesion functional, serves validating the new boundary conditions by computing structural properties of this defect and comparing these with results from the literature. Lowest energy configurations of the dislocated crystal have been obtained by molecular statics incorporating the new boundary conditions. The associated displacement and energy landscapes reveal conformal to the predictions of the elastic theory for a screw dislocation embedded in an infinitely extended crystal. In particular, no energy gradients and positional mismatch of atoms are found at the terminations of the computational box, validating thereby the new boundary conditions. Furthermore, it is shown that the structure, the spatial extension, and the excess energy of the two possible core polarizations of this dislocation compare consistently with existing findings for this and other bcc metals. Close to the dislocation line, energy minimization triggers the emergence of anelastic edge displacements extending over distances unexpectedly much larger than the dislocation core radius. Therefore, the conclusion is reached that in molecular simulations, the transverse to the dislocation line dimensions of the atomistic model should be taken considerably larger than it is accustomed. Perspectives opened by the present work are briefly discussed.

Asynchronous Double-Frame-Exposure Binocular-Camera With Pixel-Level Pipeline Architecture for High-Speed Motion Tracking

The synchronous double-frame exposure (S-DFE), also called frame-straddling, has been widely applied for commercial video-based velocity measurements to provide high-speed velocimetry-flow images. Nevertheless, no low-cost, high-speed cameras offer the video quality that researchers, scientists, and industry demand. This brief presents an asynchronous DFE (A-DFE) method with a binocular camera for motion estimation, which captures double frames with the scalable time interval of the dual generic cameras. This time interval can significantly improve the upper limit of displacements of the motion, which is commonly solved by an expensive high-speed camera. A dedicated hardware architecture is designed to implement the perspective transformation and Wallis filter to eliminate the two cameras’ position mismatch and brightness variance. We build a high-speed Lucas-Kanade optical flow estimation system with A-DFE on the XILINX Spartan-7 FPGA platform with MT9V034 CMOS image sensors. The shortest time interval can reach 1.06 ns, which means a significant improvement of the upper limit of the measurement velocity. Except for the image sensor, the compact, fully parallel architecture can attain energy efficiency with 3.23 nJ/pixel on a low-cost FPGA device.

Research on the Dynamic Monitoring Technology of Road Subgrades with Time-Lapse Full-Coverage 3D Ground Penetrating Radar (GPR)

Road safety is important for the rapid development of the economy and society. Thus, it is of great significance to monitor the dynamic changing processes of road diseases, such as cavities, to provide a basis for the daily maintenance of roads and prevent any possible car accidents. The ground penetrating radar (GPR) technology is widely used in road disease detection due to its advantages of nondestructiveness, rapidness, and high resolution. Traditionally, one-time 2D GPR detection cannot obtain the 3D spatial changes of subgrades. Thus, we developed a road subgrade monitoring method based on the time-lapse full-coverage (TLFC) 3D GPR technique by focusing on solving the key problems of time and spatial position mismatches in experimental data. Moreover, we used the time zero consistency correction, 3D data combination, and spatial position matching methods, as they greatly improve the 3D imaging quality of underground spaces. Finally, the time-lapse attribute analysis method was used in the TLFC 3D GPR data to obtain detailed characteristics and an overall rule of the dynamic subgrade change. Overall, this research proves that TLFC 3D GPR is an optimal choice for road subgrade monitoring.

Charge Transport in a Multiterminal DNA Tetrahedron: Interplay among Contact Position, Disorder, and Base-Pair Mismatch

As a secondary structure of DNA, DNA tetrahedra exhibit intriguing charge transport phenomena and provide a promising platform for wide applications like biosensors, as shown in recent electrochemical experiments. Here, we study charge transport in a multi-terminal DNA tetrahedron, finding that its charge transport properties strongly depend upon the interplay among contact position, on-site energy disorder, and base-pair mismatch. Our results indicate that the charge transport efficiency is nearly independent of contact position in the weak disorder regime, and is dramatically declined by the occurrence of a single base-pair mismatch between the source and the drain, in accordance with experimental results [J. Am. Chem. Soc. {\bf 134}, 13148 (2012); Chem. Sci. {\bf 9}, 979 (2018)]. By contrast, the charge transport efficiency could be enhanced monotonically by shifting the source toward the drain in the strong disorder regime, and be increased when the base-pair mismatch takes place exactly at the contact position. In particular, when the source moves successively from the top vertex to the drain, the charge transport through the tetrahedral DNA device can be separated into three regimes, ranging from disorder-induced linear decrement of charge transport to disorder-insensitive charge transport, and to disorder-enhanced charge transport. Finally, we predict that the DNA tetrahedron functions as a more efficient spin filter compared to double-stranded DNA and opposite spin polarization could be observed at different drains, which may be used to separate spin-unpolarized electrons into spin-up ones and spin-down ones. These results could be readily checked by electrochemical measurements and may help for designing novel DNA tetrahedron-based molecular nanodevices.

SCIFI: 3D face reconstruction via smartphone screen lighting

3D face reconstruction based on smartphones has a wide range of applications, such as face recognition, liveness detection, face animation, etc. To realize this function, these smartphones have been deployed with specialized hardware modules (infrared dot projector or depth sensor). However, it will inevitably increase the production cost of smartphones and the operation difficulty of users. In this article, we propose a smartphone screen illumination-based face reconstructIon (SCIFI) framework, which only relies on the front camera and screen lighting. Specifically, we have investigated the calibrated planar lighting to achieve the fine-grained textures in Lambertian-based reconstruction. Further, we introduce the face landmark to align multiple photographs, which aims to adjust the position mismatch caused by hand jitter. Moreover, we propose two different methods to eliminate outlier normals based on the characteristics of human face. Extensive experiments based on different environments (dark and bright), different lighting pattern (4-zones and 9-zones), and different testing subjects have validated the effectiveness and robustness of SCIFI in reconstructing the 3D face surface with a favorable surface shape as well as micro facial texture.