Resolution Performance Research Articles

Family of Conglomerate-Forming Systems Composed of Chlocyphos and Alkyl-amine. Assessment of Their Resolution Performances by Using Various Modes of Preferential Crystallization

The present study aimed at screening conglomerate derivatives of racemic chlocyphos (4-(2-chlorophenyl)-5,5-dimethyl-2-hydroxy-1,3,2-dioxaphosphorinane 2-oxide) and to perform enantiomeric separati...

Abstract 612: Automated Analysis of Displacement From Intravital Multiphoton Microscopy in Mouse Ventricle

Background: Multiphoton microscopy (MPM) has enabled in vivo time-lapse imaging of the heart that shows motion of cells within the tissue with micrometer resolution. We developed automated analysis techniques to quantify cellular motion from in vivo cardiac MPM images throughout the cardiac cycle. Methods: Intravital cardiac MPM of the beating mouse heart was performed on 26 week-old, C57Bl6 mice (n=6). Image volumes (100 μm deep) were acquired at 30 frames per second while recording the electrocardiogram and respiratory pressure. An image volume was reconstructed by assembling lines acquired nearest to a specified point in the cardio-respiratory phase space (Fig. a). Motion was calculated as the three-dimensional transformation required to register the reconstructed images to the image at the most stable cardiac phase. Results: Volumes were reconstructed in 50 intervals across the cardiac phase that show vasculature (intravenous Texas-red dextran, red) and cardiomyocytes (rhodamine 6G, cyan) moving across the field of view (Fig. b). Automated analysis indicated a maximum displacement occurring at 16 % (anterior-posterior), 36 % (base-apex) and 38 % (epi-endocardial) of the cardiac cycle defined by R-wave. Comparison by manual tracking of features across the cardiac cycle at a subset of phases (10 cardiac phases at peak exhalation) validated the automated measurement (Fig. c). Automated motion tracking shows superior performance in the spatial resolution and speed of analysis. Conclusions: We have shown a novel, fast, and accurate technique for characterizing cardiac motion from in vivo cardiac MPM to study the performance of the contractile cells in health and disease.

Entity Resolution for Big Data using Combination of Supervised Meta-Blocking and pay-as-you-go Configuration

Entity resolution refers to the method of identifying the same real world object from multiple data sets. In Data cleaning and data integration application, entity resolution is an important process. When data is large the task of entity resolution becomes complex and time consuming. End-to-end entity resolution proposal involves stages like blocking (efficiently identifies duplicates), detailed comparison (refines blocking output) and clustering (identifies the set of records which may refer to the same entity). In this paper, an approach for feedback based optimization of complete entity resolution is proposed in which supervised meta-blocking is used for blocking stage. This paper proposes a technique for entity resolution which does optimization of each phase of entity resolution with benefits of supervised Meta-blocking to improve performance of entity resolution for big data

Investigation on multi-body dynamics based approach to the toolpath generation for ultraprecision machining of freeform surfaces

This article presents an innovative approach to toolpath generation for ultraprecision machining of freeform optic surfaces based on the principle of Automatic Dynamics Analysis of Mechanical Systems. As components with freeform surfaces often have non-rotational symmetry, there are potential challenges facing their ultraprecision machining through single-point diamond turning, such as the projected points in complex large sag surfaces, which likely find it difficult to communicate with the control system and, thus, do not perform successfully. In ultraprecision machining, to achieve the highest performance in freeform surface resolution, the factors of dynamics, material and mechanical stiffness, frictions, tooling and accuracy of the servo component should be considered. The investigation is focused on an integrated approach and the associated scientific understanding of precision engineering design, ultraprecision machining and metrology of freeform surfaces as well as their application perspective. In this approach, the toolpath for very complex freeform surfaces can be generated using the Newton–Raphson method to solve the kinematics and dynamics equations of motion. The effect of friction and contact force are also investigated for accurate toolpath curve generation. Moreover, the Gear stiff (GSTIFF)/ Wielenga stiff (WSTIFF) integrator for solving the non-linear equations of motion is employed, and the result shows the time step size, playing a critical role in generating toolpath curves with a higher accuracy and resolution.

Initial assessment of multilayer silicon detectors for hard X-ray imaging

Silicon detectors with lower material budget, ultrafast readout and radiation hardness are under developments. These unique features make pixelized silicon sensors a good option for hard X-ray imaging. To verify the performance of spatial resolution and energy sensitivity of silicon sensors to hard X-rays, a two layer setup of Pixelink PL-D725MU sensors has been tested at the Argonne National Laboratory Advanced Photon Source (APS) ID-10 sector with 29.2 keV high photon flux (4.5×10^8 to 4.5×10^(10) photons per second) X-rays. Better than 3 μm spatial resolution and clear energy characterization have been achieved by both layers. Commercial CMOS sensors with superior spatial resolution could be used for phase contrast imaging in current synchrotrons. These studies pave the path for future multilayer ultrafast silicon sensor development with ns to sub-ns readout speeds in hard X-ray imaging at synchrotrons and XFEL beamlines.

Pivot single-difference ambiguity resolution for multi-GNSS positioning with non-overlapping frequencies

Ambiguity resolution in real-time kinematic (RTK) positioning is increasingly dependent on the combination of multi-GNSS observations, especially in challenging signal environments such as urban canyon areas. By applying a priori calibration to the receiver-dependent differential inter-system bias (DISB), a DISB-fixed multi-GNSS combination method with overlapping frequencies is widely used to strengthen the positioning model. However, as for non-overlapping frequencies, the differential inter-frequency bias (DIFB), which correlates with ambiguities, needs to be further corrected in case of the DISB-fixed multi-GNSS combination method. Since the DIFB is related to a pivot single-difference (SD) ambiguity, the DIFB is generally reduced by means of a SD ambiguity resolution. Owing to the code multipath and the code–carrier inconsistency, the traditional carrier-minus-code combination method will result in a large SD ambiguity bias and affect the DIFB correction. Thus, a SD ambiguity resolution method based on the integer least squares ambiguity estimator is proposed to deal with the issue. A kinematic experiment is conducted in urban areas, which is based on single-frequency observations from GPS L1 and BDS B1. The result shows that the proposed method can improve the performance of ambiguity resolution and positioning continuity when compared with the traditional multi-GNSS RTK methods.

Fast and robust Fourier domain ranging for light field

A light-field camera combines optics and computation to provide the ability to perform ranging. Many methods and algorithms, which are time-consuming and noise-sensitive, have been proposed for per-pixel depth estimation. We present a Fourier domain ranging method for light fields (LFs). Instead of estimating the depth for every pixel, we attempt to detect the depths of the different planes at which objects are located. The method is somewhat like using the energy in the focal stack, but it is carried out in a more efficient way. Our method has the advantages of speediness and robustness compared with traditional per-pixel depth estimation methods. In addition to the ranging algorithm, we also demonstrate the idea and application of a region adaptive denoising filter, in which the depth parameters are tuned by the proposed method. We include results for synthetic LFs, the Stanford LF archives, and LFs captured with a Lytro camera, exploiting the algorithm complexity, accuracy, depth resolution, and noise performance of our method. Our method uses less computation and is more robust than per-pixel depth estimation, making it appropriate for many applications, such as autorefocusing and autodenoising.

Characterization of a Cs2LiYCl6: Ce3+ scintillator coupled with two silicon photomultiplier arrays of different sizes

Neutrons produced by cosmic rays comprise the main factor in radiation hazards for astronauts and spacecraft during space exploration. A silicon-photomultiplier- (SiPM-) array-coupled Cs2LiYCl6: Ce3+ (CLYC) detector was proposed to measure neutrons onboard spacecraft. Since both light-collection efficiency and thermal noise rate are proportional to a SiPM’s size, it is necessary to compare CLYC’s characterization when coupled with SiPM arrays of different sizes. In this paper, a 4×4 array and an 8×8 array, both of which are composed of 3×3-mm2 SiPM elements, were coupled to a Φ38 mm×38 mm cylindrical CLYC detector. The energy resolution, pulse-shape-discrimination (PSD) performance, and temperature dependence were tested with two gamma-ray sources and a neutron source. Results indicate that both energy resolution and PSD performance mainly benefit from the higher light-collection efficiency of the large array. The peak centroids of 137Cs varied by ∼20% in the testing temperature region from -35 °C to +55 °C.

Analysis of the influence of the accelerating structure on the performance of pulse-dilation framing cameras

In this work a pulse-dilation framing camera was designed by employing a telescope imaging system. The accelerating electric field and the field emission current on the photocathode were simulated and the influence of the accelerating structure on the temporal and the spatial resolution performance of the camera were analyzed. The results reveal that the temporal and the spatial performance are drastically affected upon an increase in the accelerating distance from 1 mm to 5 mm. Moreover, the decrease of the electric field from 3 kV/mm to 0.6 kV/mm, which is caused by the increase of the temporal resolution of the camera from 3 ps to 4.5 ps are investigated. The decrease in the field emission current on the photocathode from 1.1 A/m2 to 0.21 A/m2 drastically affects the spatial resolution of the camera, which passes from 66.9 μm to 71.1 μm. This research provides a theoretical basis for the development of pulse-dilation framing cameras with higher temporal and spatial resolution.

Neural recovery machine for Chinese dropped pronoun

Dropped pronouns (DPs) are ubiquitous in prodrop languages like Chinese, Japanese etc. Previous work mainly focused on painstakingly exploring the empirical features for DPs recovery. In this paper, we propose a neural recovery machine (NRM) to model and recover DPs in Chinese to avoid the non-trivial feature engineering process. The experimental results show that the proposed NRM significantly outperforms the state-of-the-art approaches on two heterogeneous datasets. Further experimental results of Chinese zero pronoun (ZP) resolution show that the performance of ZP resolution can also be improved by recovering the ZPs to DPs.

Impaired processing of response conflicts in mesial temporal lobe epilepsy.

Increasing evidence from neuroimaging studies points towards a hippocampal role in resolving approach-avoidance goal conflicts. Furthermore, previous neuroimaging findings suggest that the hippocampus (HC) contributes to successful conflict resolution as it is measured, for example, in a Stroop paradigm. However, it is still an open question whether the hippocampus is indeed causally relevant for resolving cognitive conflicts. Here, we investigated whether conflict resolution performance is affected by hippocampal pathology. N=30 patients with mesial temporal lobe epilepsy (MTLE), almost exclusively showing MRI signs of hippocampal sclerosis, and an equal number of age-matched healthy controls performed an auditory Stroop paradigm. Participants listened to the words 'high' and 'low', spoken in either a high or a low pitch. Subjects' response time and accuracy to the phonetic information in the presence of incongruent (conflict trials) or congruent (non-conflict trials) semantic information were assessed. In addition, patients' regional grey matter (GM) brain volumes were analysed. We observed an increased effect of conflict on accuracy in patients with MTLE compared to healthy controls. This effect was negatively correlated with right HC volume. The results suggest that the impairment in the resolution of a response conflict is related to hippocampal structural integrity and thus add further support to the notion that the HC is not only involved but even causally relevant for successful cognitive conflict processing.

Amino acid modified carbon nanotubes with optimal pore size for chiral separation

ABSTRACTPrecisely controlling pore size of porous materials is of great importance for chiral separation, but a great challenge in practical applications. In contrast, the molecular dynamics (MD) simulation can be quite a convenient way to determine the effect of the pore dimension on the chiral resolution performances and thus to define the optimal pore size. In this work, inner-wall functionalised carbon nanotubes (CNTs) were used as porous materials and D- and L-phenylalanine were selected as chiral probes. The enantioseparation behaviour was investigated via varying the pore diameter of CNTs, controlling the grafting amount of chiral selectors and tuning the spacer length. Results show that varying the pore size has a significant effect on the enantioselectivity. Additionally, the effect of the introduction of varying the grafting ratio and tuning the spacer length on the chiral separation performance was also examined in this work. It was found that varying the grafting ratio, especially the spacer length between substrates and selectors, could also be one of the most effective alternatives to improving enantioselectivity. Our findings can provide a guidance for the practical applications in the chiral separation.

Chinese Zero Pronoun Resolution

Chinese zero pronoun (ZP) resolution plays a critical role in discourse analysis. Different from traditional mention-to-mention approaches, this article proposes a chain-to-chain approach to improve the performance of ZP resolution in three aspects. First, consecutive ZPs are clustered into coreferential chains, each working as one independent anaphor as a whole. In this way, those ZPs far away from their overt antecedents can be bridged via other consecutive ZPs in the same coreferential chains and thus better resolved. Second, common noun phrases (NPs) are automatically grouped into coreferential chains using traditional approaches, each working as one independent antecedent candidate as a whole. That is, those NPs occurring in the same coreferential chain are viewed as one antecedent candidate as a whole, and ZP resolution is made between ZP coreferential chains and common NP coreferential chains. In this way, the performance can be much improved due to the effective reduction of the search space by pruning singletons and negative instances. Third and finally, additional features from ZP and common NP coreferential chains are employed to better represent anaphors and their antecedent candidates, respectively. Comprehensive experiments on the OntoNotes V5.0 corpus show that our chain-to-chain approach significantly outperforms the state-of-the-art mention-to-mention approaches. To our knowledge, this is the first work to resolve zero pronouns in a chain-to-chain way.

MUSIC-Like Algorithm for Source Localization in Electrical Impedance Tomography

In electrical impedance tomography (EIT), the noise amplified solution caused during matrix inversion can be avoided with nonparametric spectral-based estimation when the conductivity variation is bounded and spatially sparse. Among many spectral-based algorithms used in direction-of-arrival estimation, an algorithm called multiple signal classification (MUSIC) is one of the most well-known algorithms that has super resolution performance. However, its dependence on the model-order estimation can lead to performance degradation, especially for quasi-static environment, such as EIT application, and this is due to source location changes and conductivity variation. In this paper, the relationship between source position, conductivity variation, ill-conditioned array manifold, and eigenvalues of the covariance matrix are explored. An algorithm called MUSIC-like, which has high resolution performance comparable to MUSIC, is then proposed for EIT application. It is formulated under the beamforming framework and, therefore, does not require an estimation of model order from the covariance matrix. Simulation results show that the proposed method is capable of obtaining high resolution performance under various noise levels. An 8-electrode EIT system prototype was built using the proposed method, and experimental results confirm the high resolution performance capability of the proposed method.

How Does Allocation of Emotional Stimuli Impact Working Memory Tasks? An Overview.

In this review, we investigated the influence of happy/pleasurable and sad/unpleasant emotional stimuli on working memory (WM) performance. Twenty-eight out of 356 articles were reviewed. We observed that emotional stimuli were used as mood inductors or as targets comprising the WM task. Results showed that WM modalities were influenced differently when updating, interference resolution, span, and complex tasks were applied. Specifically, we found distinct effects of emotional stimuli for updating tasks, in which (a) verbal modality seems to be impaired regardless of the emotional valence used compared to neutral stimuli, (b) visual updating processes appear to be improved by emotional stimuli as the targets of the task, and (c) emotional words improved interference resolution performance. As for storage, span, and complex WM tasks, sad/unpleasant emotional stimuli seem to decrease both verbal and visuospatial modalities when used as emotional inductors.

Improvement of Performance Degradation in Synthetic Aperture Extension of Enhanced Axial Resolution Ultrasound Imaging Based on Frequency Sweep.

We are studying a method based on the carrier frequency sweep for axial high resolution ultrasonic imaging to provide the range resolution that corresponds to the carrier wavelength. The first proposal for this type of method was based on the focused pulse transmission. Then, to improve the frame rate, the method was extended to a synthetic aperture-type method that transmits divergent pulses. While the method is effective in terms of the frame rate, degradation of the enhanced axial resolution performance is a concern. Therefore, using finite element method simulations and simple experiments, the performance of the synthetic aperture method with high axial resolution is evaluated via comparison with the original method using focused pulses. The evaluation confirmed that the performance degradation of the synthetic aperture method is caused by weakness in the transmitted wave intensity and deterioration of the phase coherence in the reception beamforming. Based on this result, we propose a method that is less affected by the latter cause and show its effectiveness.

Hybrid CMOS detectors for the Lynx x-ray surveyor high definition x-ray imager

X-ray hybrid CMOS detectors (HCDs) are a promising candidate for future x-ray missions requiring high throughput and fine angular resolution along with large field-of-view, such as the high-definition x-ray imager (HDXI) instrument on the Lynx x-ray surveyor mission concept. These devices offer fast readout capability, low power consumption, and radiation hardness while maintaining high detection efficiency from 0.2 to 10 keV. In addition, x-ray hybrid CMOS sensors may be fabricated with small pixel sizes to accommodate high-resolution optics and have shown great improvements in recent years in noise and spectral resolution performance. In particular, 12.5-{\mu}m pitch prototype devices that include in-pixel correlated double sampling capability and crosstalk eliminating capacitive transimpedance amplifiers, have been fabricated and tested. These detectors have achieved read noise as low as 5.4 e-, and we measure the best energy resolution to be 148 eV (2.5%) at 5.9 keV and 78 eV (14.9%) at 0.53 keV. We will describe the characterization of these prototype small-pixel x-ray HCDs, and we will discuss their applicability to the HDXI instrument on Lynx.

Segmented convolutional gated recurrent neural networks for human activity recognition in ultra-wideband radar

The automatic detection and recognition of human activities are valuable for physical security, gaming, and intelligent interface. Compared to an optical recognition system, radar is more robust to variations in lighting conditions and occlusions. The centimeter-wave ultra-wideband radar can even track human motion when the target is fully occluded from it. In this work, we propose a neural network architecture, namely segmented convolutional gated recurrent neural network (SCGRNN), to recognize human activities based on micro-Doppler spectrograms measured by the ultra-wideband radar. Unlike most existing approaches which treat the micro-Doppler spectrograms the same way as natural images, we extract segmented features of spectrograms via convolution operation and encode the feature maps along the time axis with gated recurrent units. Taking advantage of regularities in both the time and Doppler frequency domains in this way, our model can detect activities with arbitrary lengths. The experiments show that our method outperforms existing models in fine temporal resolution, noise robustness, and generalization performance. The radar system can thus recognize human behavior when visible light is blocked by opaque objects.

Ultrasound grayscale image quality comparison between a 2D intracavitary transducer and a 3D intracavitary transducer used in 2D mode: A phantom study.

PurposeIt is unclear if a 3D transducer with the special design of mechanical swing or 2D array could provide acceptable 2D grayscale image quality for the general diagnosis purpose. The aim of this study is to compare the 2D image quality of a 3D intracavitary transducer with a conventional 2D intracavitary transducer using clinically relevant phantom experiments.MethodsAll measurements were performed on a GE Logiq E9 scanner with both a 2D (IC5‐9‐D) and a 3D (RIC5‐9‐D) transducer used in 2D mode. Selection of phantom targets and acquisition parameters were determined from analysis of 33 clinical pelvic exams. Depth of penetration (DOP), contrast response, contrast of anechoic cylinders (diameter: 6.7 mm) at 1.5 and 4.5 cm depths in transverse planes, and in‐plane resolution represented by full‐width half‐maximum of pin targets at multiple depths were measured with transmit frequencies of 7 and 8 MHz. Spherical signal‐noise‐ratio (SNR) (diameter: 4 and 2 mm) at multiple depths were measured at 8 MHz.ResultsRIC5‐9‐D demonstrated <8% decrease in DOP for both transmit frequencies (7 MHz: 69.7 ± 8.2 mm; 8 MHz: 64.3 ± 7.8 mm) compared with those from IC5‐9‐D (7 MHz: 73.9 ± 4.4 mm; 8 MHz: 69.4 ± 7.8 mm). A decreased anechoic contrast was observed with a 4.5 cm depth for RIC5‐9‐D (7 MHz: 23.2 ± 1.8 dB, P > 0.05; 8 MHz: 17.7 ± 0.9 dB, P < 0.01) compared with IC5‐9‐D (7 MHz: 25.9 ± 1.2 dB; 8 MHz: 21.5 ± 0.8 dB). The contrast response and spatial resolution performance were comparable between the two transducers. RIC5‐9‐D showed comparable SNR of anechoic spheres compared to IC5‐9‐D.Conclusions2D images from a 3D probe exhibited comparable overall image quality for routine clinical pelvic imaging.

High resolution real-time complex modulation using single spatial light modulator

Limited spatial resolution and poor real-time performance are crucial issues in complex modulation. In this paper, a novel and non-iterative scheme for real-time complex modulation with a high spatial resolution is demonstrated. Firstly, the desired complex amplitude field is decomposed into two phase-only masks, which are subsequently displayed side by side on a spatial light modulator. Then, two phase-shift masks at the Fourier transform plane are employed to make beams, modulated by the two phase-only masks, interfering with each other. Finally, an accurate reconstruction of the desired complex amplitude can be achieved theoretically at the output plane. By this method, misalignment tolerance of the proposed scheme is effectively enhanced, which significantly decreases the difficulty of realization. Besides, this method is quite simple and requires only a little commonly used optical elements. Consequently, the whole modulation procedure can be fast and easy to implement. Simulation results verified the validity of our proposed method. It may be a promising means for numerous optical applications, such as holography.