Linear Matching Research Articles

Vibration and Noise Control Technology for High-speed Railway

The operation of high-speed railway will cause environmental noise and vibration problems, which will directly affect the sustainable development of railway station's comprehensive development. In solving this problem, the traditional method generally considers the three aspects of sound source, vibration source and propagation path, but often fail to achieve satisfactory control effect. This paper presents a high-speed railway vibration and noise control technology based on linear feedback matching filter. Firstly, the propagation path model of noise in high-speed railway station is constructed and the noise signal is separated. At the same time, linear feedback matching filter technique is used to make in-phase addition to the propagating sound. The linear feedback filter is designed by combining the binary wavelet technique to suppress the noise and vibration. The results show that the proposed technique overcomes the weakness of conventional control model and the noise vibration control is smoother than that of the traditional method.

Linear trace similarity matching based on improved longest common substring

The linear trace indicates the external morphological structure of the contact portion of clamping and cutting tools, which is not easy to be destroyed, has a high occurrence rate and high significant on identification. It is of great significance for prosecutor to determine the nature of the case and determine the tools used in the crime so as to find the criminals. The traditional linear trace analyzing methods include microscopy, manual comparison of characteristics, image recognition and three-dimensional scanning methods. The single-point laser picks up the toolmark detection signal, and the longest common substring is obtained after noise reduction. In addition, the improved dynamic programming algorithm calculates and generates matching results. Finally, the effectiveness of the algorithm is verified by the actual detection data.

Long-term trends of Chlamydia trachomatis in a clinic population at the Royal Women's Hospital, Melbourne.

Chlamydia trachomatis (C.trachomatis) prevalence has been reported to be increasing. Whether this is a true increase over time or confounded by increases in testing and/or use of more sensitive assays is to be determined. One laboratory service has been detecting C.trachomatis for the past 30years within the Royal Women's Hospital Melbourne. We conducted a retrospective audit of records over the period 1986-2016 from a clinic population routinely offered chlamydia screening. These were women presenting for family planning advice (termination of pregnancy, intrauterine device insertion or considered at high risk), who underwent chlamydia testing in the context of various diagnostic assays used over this time period. Assays utilised included culture, enzyme immunoassay (EIA), DNA probe, and nucleic acid amplification testing (NAAT). Non-parametric test for trend was used to determine significant differences between prevalence estimates across ordered groups. Least squares regression was conducted to describe a linear trend matching known data points. Overall, there was no significant change for chlamydia prevalence which was 2.2%, in the 30-year study period (P=0.7). Over time diagnostic assays changed from culture, to EIA, DNA probe, to the more sensitive NAAT. The bulk of the positives were in women under 25years of age (57%). Chlamydia prevalence has been stable over 30years, remaining a problem in young women. Screening for those at risk needs underscoring in a national sexual health program.

An Image Cues Coding Approach for 3D Human Pose Estimation

Although Deep Convolutional Neural Networks (DCNNs) facilitate the evolution of 3D human pose estimation, ambiguity remains the most challenging problem in such tasks. Inspired by the Human Perception Mechanism (HPM), we propose an image-to-pose coding method to fill the gap between image cues and 3D poses, thereby alleviating the ambiguity of 3D human pose estimation. First, in 3D pose space, we divide the whole 3D pose space into multiple subregions named pose codes , turning a disambiguation problem into a classification problem. The proposed coding mechanism covers multiple camera views and provides a complete description for 3D pose space. Second, it is noteworthy that the articulated structure of the human body lies on a sophisticated product manifold and the error accumulation in the chain structure will undoubtedly affect the coding performance. Therefore, in image space, we extract the image cues from independent local image patches rather than the whole image. The mapping relationship between image cues and 3D pose codes is established by a set of DCNNs. The image-to-pose coding method transforms the implicit image cues into explicit constraints. Finally, the image-to-pose coding method is integrated into a linear matching mechanism to construct a 3D pose estimation method that effectively alleviates the ambiguity. We conduct extensive experiments on widely used public benchmarks. The experimental results show that our method effectively alleviates the ambiguity in 3D pose recovery and is robust to the variations of view.

Evaluation of gap-filling methods for Landsat 7 ETM+ SLC-off image for LULC classification in a heterogeneous landscape of West Africa

ABSTRACTThe Landsat mission which has existed over five decades has remained at the forefront of providing consistent moderate spatial and temporal resolution optical images of the earth. The failure of the scan line corrector (SLC) on board the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) in May 2003 has permanently resulted in data gaps on each Landsat 7 scene. Due to the obvious negative impacts on the image usability, a number of methods have been developed to fill the no-data areas in the image. This study assessed the performance of four Landsat 7 ETM+ SLC-off gap-filling methods in a highly heterogeneous landscape of West Africa for two different seasons (dry and rainy). The methods considered are: (1) Weighted Linear Regression (WLR) integrated with Laplacian Prior Regularization Method (LPRM), (2) Localised Linear Histogram Matching (LLHM), (3) Neighbourhood Similar Pixel Interpolator (NSPI) and (4) Geostatistical Neighbourhood Similar Pixel Interpolator (GNSPI). All the images used were Landsat 7 ETM+ SLC-off images, temporally close and from the same season for each set of time step. Visual comparison, mean, and standard deviations of the histograms of all bands of only the filled areas were used to assess the results. Additionally, overall accuracy (OA), kappa coefficient (κ), and balanced accuracy (BA) per class were used to evaluate a land use/cover (LULC) classification based on the gap-filled images. Visually, all the four methods were able to completely fill the gaps in the Landsat 7 ETM+ SLC-off image. They all look similar and spatially continuous with no anomalies or artefacts on them. The histograms from each band for only the filled areas for all the four methods also gave similar means and standard deviations in most cases. All the four gap-filling methods provided satisfactory results (OA >96% and κ> 0.937 in all methods for images in the dry season and OA >93% and κ> 0.877 for the image in the rainy season) in the land cover classification considering the complexity of the study area. But the GNSPI was superiority in all cases with the highest OA of 97.1% and κ of 0.947 in the dry season and OA of 94.6% and κ of 0.899 in the rainy season. This implies that the GNSPI is more robust in gap filling of Landsat 7 ETM+ SLC-off images than the other three methods in a heterogeneous landscape of West Africa regardless of the season. This study suggests that gap filling of Landsat 7 ETM+ SLC-off images will help to increase the number of Landsat images needed to build time-series data for a data-scarce region such as West Africa.

Nonlinear phase matching in parametric four-wave mixing process of Cs vapor

Phase matching plays an important role on the nonlinear process. The linear phase matching in parametric four-wave mixing (FWM) process of Cs vapor is firstly studied and we find out that linear phase matching can be implemented within narrow range of frequency offsets for involved pumping light. Considering the high pumping power intensity, we innovatively take the influence of nonlinear refractive index to phase matching into account. The relationship between threshold pump intensity and frequency offsets is discovered, and it makes up a complicated curved surface. The threshold has the minimum value when the frequency offset satisfies the condition of v1 + v2 = 0. In addition, these simulation results could provide support for further study and pumping parameters selection in FWM process of Cs vapor.

Skeleton-Based Gait Recognition via Robust Frame-Level Matching

Gait is a useful biometric feature for human identification in video surveillance applications since it can be obtained without subject cooperation. In recent years, model-based gait recognition using a 3D skeleton has been widely studied through view-invariant modeling and kinematic gait analysis. However, existing methods integrate all frame-level feature vectors using the same criterion, even though skeleton information is highly sensitive to changes in covariate conditions such as clothing, carrying, and occlusion. The scheme inevitably reduces the frame-level discriminative power and eventually degrades performance. Instead, we propose a robust frame-level matching method for gait recognition that minimizes the influence of noisy patterns as well as secures the frame-level discriminative power. To this end, we measure the skeleton quality in terms of body symmetry for each frame. Based on the quality, we construct a quality-adjusted cost matrix between input frames and registered frames to prevent matching with noisy patterns. Our two-stage linear matching is then applied to the cost matrix to compute a frame-level discriminative score including similarity and margin. In the end, the identity of a probe is determined by a weighted majority voting scheme via frame-level scores. It enhances the robustness against inaccurate skeleton estimation results by assigning different weights for each frame based on the score. Our approach outperforms the state-of-the-art methods on three public datasets (UPCVgait, UPCVgaitK2, and SDUgait) and a new gait dataset which we create with consideration of unpredictable behaviors while walking. In addition, we demonstrate that our method is robust to skeleton estimation error, partial occlusion, and data loss. The CILgait dataset and MATLAB code are available at https://sites.google.com/site/seokeonchoi/gait-recognition .

Wave power extraction from multiple oscillating water columns along a straight coast

The integration of oscillating water column (OWC) wave energy converters into a coastal structure (breakwater, jetty, pier, etc.) or, more generally, their installation along the coast is an effective way to increase the accessibility of wave power exploitation. In this paper, a theoretical model is developed based on the linear potential flow theory and eigenfunction matching method to evaluate the hydrodynamic performance of an array of OWCs installed along a vertical straight coast. The chamber of each OWC consists of a hollow vertical circular cylinder, which is half embedded in the wall. The OWC chambers in the theoretical model may have different sizes, i.e. different values of the radius, wall thickness and submergence. At the top of each chamber, a Wells turbine is installed to extract power. The effects of the Wells turbine together with the air compressibility are taken into account as a linear power take-off system. The hydrodynamic and wave power extraction performance of the multiple coast-integrated OWCs is compared with that of a single offshore/coast-integrated OWC and of multiple offshore OWCs. More specifically, we analyse the role of the incident wave direction, chamber size (i.e. radius, wall thickness and submergence), spacing between OWCs and number of OWCs by means of the present theoretical model. It is shown that wave power extraction from the coast-integrated OWCs for a certain range of wave conditions can be significantly enhanced due to both the constructive array effect and the constructive coast effect.

MATCHING SUBSIDIES AND VOLUNTARY CONTRIBUTIONS: A REVIEW

AbstractThis paper provides a synthesis of the experimental literature on matching subsidies in the context of charitable giving. We classify results according to four different outcome variables frequently considered in the literature and address (i) short‐term effects of linear matching, (ii) the role of the matching rate, (iii) context‐dependence of behavioural responses, (iv) the relevance of the price of giving, (v) long‐term effects and (vi) nonlinear matching schemes. Based on this comprehensive review, we highlight several avenues for future research, such as putting stronger emphasis on competition in fundraising, long‐term effects or heterogeneity in responses.

On matchable subsets in abelian groups and their linear analogues

In this paper, we introduce the notions of matching matrices in groups and vector spaces, which lead to some necessary conditions for existence of acyclic matching in abelian groups and its linear analogue. We also study the linear local matching property in field extensions to find a dimension criterion for linear locally matchable bases. Moreover, we define the weakly locally matchable subspaces and we investigate their relations with matchable subspaces. We provide an upper bound for the dimension of primitive subspaces in a separable field extension. We employ MATLAB coding to investigate the existence of acyclic matchings in finite cyclic groups. Finally, a possible research problem on matchings in n-groups is presented. Our tools in this paper mix combinatorics and linear algebra.

Teleworkers in Italy: who are they? Do they make more?

PurposeThe purpose of this paper is to investigate the determinants of the probability of being a teleworker and the extent of earnings differentials between teleworkers and traditional employees.Design/methodology/approachThe analysis is grounded on a theoretical framework depicting endogenous telework assignment and wage variations based on individual bargaining. The empirical strategy allows for non-random telework assignment, generating from individual- and job-specific observed as well as unobserved factors.FindingsResults are based on the Italian labor force survey and uncover a key role of gender, higher education and family composition as determinants of the probability of teleworking. Furthermore, teleworkers enjoy a wage premium ranging between 2.7 and 8 percent.Originality/valueAccounting for observed individual and job-specific effects, by both standard linear regression and propensity score matching, largely reduces the extent of wage premium emerging from unconditional descriptives; the results of an endogenous switching regression model however suggest that failing to properly care for unobserved factors leads to the underestimation of returns to telework.

Nonlinear Moment Matching for the Simulation-Free Reduction of Structural Systems

This paper transfers the concept of moment matching to nonlinear structural systems and further provides a simulation-free reduction scheme for such nonlinear second-order models. After first presenting the steady-state interpretation of linear moment matching, we then extend this reduction concept to the nonlinear second-order case based on Astolfi [2010]. Then, similar simplifications as in Cruz Varona et al. [2019a] are proposed to achieve a simulation-free nonlinear moment matching algorithm. A discussion on the simplifications and their limitations is presented, as well as a numerical example which illustrates the efficiency of the algorithm.

Ratcheting boundary of pressurized pipe under reversed bending

Ratcheting boundary is firstly determined by experiment, elastic-plastic finite element analysis combined with C-TDF and linear matching method, which is compared with ASME/KTA and RCC-MR. Moreover, based on elastic modulus adjustment procedure, a novel method is proposed to predict the ratcheting boundary for a pressurized pipe subjected to constant internal pressure and cyclic bending loading. Comparison of ratcheting boundary of elbow pipe determined by the proposed method, elastic-plastic finite element analysis combined with C-TDF and linear matching method, which indicates that the predicted results of the proposed method are in well agreement with those of linear matching method.

Personalized Fundraising: A Field Experiment on Threshold Matching of Donations

While increasing the number of small donors, standard linear matching schemes have been shown to cause considerable crowding out in charitable giving with pronounced effects on large gifts. We propose a form of threshold matching where donations above a certain, potentially personalized, threshold are topped up with a fixed amount. We show theoretically that threshold matching can induce crowding in if appropriately personalized. In a field experiment, we explore how thresholds should be chosen depending on past donations. We find that the optimal choice of thresholds is rather bold, approximately 60-75% above past donations. Additionally, we explore how thresholds should be set for new donors as a function of their personal characteristics and demonstrate the benefits of personalization as opposed to setting general thresholds applying to all recipients of a fundraising call.

LOCAL POLARIMETRIC SYSTEM FOR MEASURING AIRCRAFT`S NAVIGATION AND PILOTING PARAMETERS

The paper considers questions of invention the local optical system for measuring navigation and piloting parameters on base on polarimetric technologies. Such system is aimed to increase the sensitivity and accuracy of definition the aircraft navigation and piloting parameters in a locally restricted airspace segment with high traffic density. The paper also deals with regarding existing methods and systems for measuring the aircraft’s piloting and navigation parameters, as well as suggest polarimetric method and the polarimetric system, that realize it. The polarimetric method for measuring the aircraft`s piloting and navigation parameters consist in measuring the polarization plane azimuth of transmitted beam and determining the spatial and plane incident angles of the incident beam, as well as the aircraft`s attitude. Proposed local polarimetric system for measuring aircraft`s navigation and piloting parameters consist two main units: measurement block and radiation block. Radiation block emits the polarized radiation with certain polarization plane azimuth and with certain dispersion aperture. Measurement block measure the polarization plane azimuth of transmitted beam and calculate polarization plane azimuth of incident radiation and its angle of incident. The proposed system allows to measure the piloting, as well as, navigation parameters at the same time with high accuracy and sensitivity. Modeling the operation of the measurement channel shows that dependencies have linear character and match well with measuring parameters. Paper results can be applied in the process of elaboration and implementation of polarimetric navigation system, for example, and requires additional theoretical and practical research.

SEMI-AUTOMATIC ROAD NETWORK EXTRACTION FROM DIGITAL IMAGES USING OBJECT-BASED CLASSIFICATION AND MORPHOLOGICAL OPERATORS

Abstract: The demand for geospatial data concerning road network is constant, due to the wide variety of application which needs this type of data. It stands out the importance of this data in cartography update cycles, that can be obtained using automated processes of feature extraction in digital images, which are more accurate, fast and less costly than the traditional methods. In this sense, this work aimed the road network extraction from RapidEye satellite imagery, by developing a hybrid methodology using techniques of object-based image classification and morphological operators. The methodology was tested in three different sites, with images acquired in distinct dates, and the extraction process was evaluated through metrics obtained from the linear matching procedure. By the proposed extraction process, were achieved in terms of correctness and completeness the values of 92.23% and 85.15% for test site 1, the values of 79.16% and 81.06% for test site 2, and the values of 82.05% and 92.22% for test site 3, respectively. The results shown that the proposed methodology presented a good performance for semi-automatic road network extraction from Rapideye images, representing an alternative to auxiliary road network database acquisition and updating.

Creep-fatigue and cyclically enhanced creep mechanisms in aluminium based metal matrix composites

An aluminium (Al, 2024T3) matrix composite reinforced with continuous alumina (Al2O3) fibres is investigated under tensile off-axis constant macro stress and thermal cyclic loading. The micromechanical approach to modelling and three different fibre cross-section geometries have been employed. The effect of creep is included by considering three dwell times at the peak temperature of the thermal loading history. The presence of the hold time gives rise to different sources of failure such as cyclic enhanced creep and creep ratchetting. These failure mechanisms are carefully discussed and assessed. The linear matching method framework has been used for the direct evaluation of the crucial parameters for creep-fatigue crack initiation assessment at the steady cycle. A detailed representation of the steady-state hysteresis loops is provided by using the strain range partitioning and a method for dealing with multiaxiality is reported with regard to the algebraic sign of the Mises-Hencky equivalent stress and strain. All the results obtained have been benchmarked by fully inelastic step-by-step (SBS) analyses. The design of a long fibre metal matrix composite should consider not only the detrimental effect of their dissimilar coefficient of thermal expansion, but also the state of stress at the interface between the matrix and fibre.

Fingerprinting Acoustic Localization Indoor Based on Cluster Analysis and Iterative Interpolation

Fingerprinting acoustic localization usually requires tremendous time and effort for database construction in sampling phase and reference points (RPs) matching in positioning phase. To improve the efficiency of this acoustic localization process, an iterative interpolation method is proposed to reduce the initial RPs needed for the required positioning accuracy by generating virtual RPs in positioning phase. Meanwhile, a two-stage matching method based on cluster analysis is proposed for computation reduction of RPs matching. Results reported show that, on the premise of ensuring positioning accuracy, two-stage matching method based on feature clustering partition can reduce the average RPs matching amount to 30.14% of the global linear matching method taken. Meanwhile, the iterative interpolation method can guarantee the positioning accuracy with only 27.77% initial RPs of the traditional method needed.

Horizontal highway segmentation optimisation using genetic algorithms

This paper presents the use of genetic algorithms (GAs) for optimising different global positioning system-based procedures for horizontal roadway alignment extraction. Two algorithms are proposed – one uses design information to guide the GA, aiming to evaluate the segmentation procedures' precision, while the other uses curve-similarity measures. The linear matching model, the discrete Fréchet distance and the modified Hausdorff distance were tested for guiding the optimisation algorithm in cases when there is no design information available. This paper also presents an extension to a segmentation method available in the literature for increasing the optimisation performance. The proposed algorithms were evaluated on a synthetic data set with 2100 curves. In the experiments, both algorithms correctly identified all the curves, with the best segmentation precision achieved by the algorithm with design information, closely followed by the curve-similarity metrics. Compared with manual segmentation, all showed good results.

The effect of cancer on the labor supply of employed men over the age of 65

This paper investigates the relationship between cancer diagnosis and the labor supply of employed men over the age of 65. While almost 60% of male cancers are diagnosed in men over the age of 65, no previous research has examined the effect that cancer has on this age group, which is surprising given the relevance of this group to public policy. With data from the Health and Retirement Study, I show that cancer has a significant negative effect on the labor supply of these workers. Using a combination of linear regression models and propensity score matching, I find that respondents who are diagnosed with cancer work 3 fewer hours per week than their non-cancer counterparts. They are also 10 percentage points more likely to stop working. This reduction seems to be driven by a deterioration in physical and mental health.