Distortion Index Research Articles

Relationship between body image distortion and body mass index and food intake in the young and middle-aged Japanese women

Relationship between body image distortion and body mass index and food intake in the young and middle-aged Japanese women

A Novel Frequency Domain Linearly Constrained Minimum Variance Filter for Speech Enhancement

A reliable speech enhancement method is important for speech applications as a pre-processing step to improve their overall performance. In this paper, we propose a novel frequency domain method for single channel speech enhancement. Conventional frequency domain methods usually neglect the correlation between neighboring time-frequency components of the signals. In the proposed method, we take this correlation into account via: 1) considering neighboring correlation for speech signals, we break down the clean speech into two uncorrelated components; 2) considering neighboring correlation for noise, we approximate the noise as a rank-1 component. Then, we design a linearly constrained minimum variance (LCMV) filter which aims at removing the dominant part of the noise, while keeping the speech signal undistorted. Performance of the proposed method is evaluated in terms of output signal to noise ratio (SNR) and speech distortion index under various noise environments. Evaluation results demonstrate that our method yields higher noise reduction and lower speech distortion compared to some recent methods.

Speech intelligibility prediction using a multi-resolution gammachirp envelope distortion index with common parameters for different noise conditions

Speech intelligibility prediction using a multi-resolution gammachirp envelope distortion index with common parameters for different noise conditions

Detecting Feigning in Adolescents on the Personality Assessment Inventory—Adolescent Form

Much of the research on identifying feigning in psychological assessment has focused on adults with less attention to adolescents. The purpose of the present study is to expand the limited literature on detecting feigning in adolescents using the Personality Assessment Inventory – Adolescent. The study included 114 nonclinical adolescents (ages 15 to 18) recruited from high schools in the Midwest who were randomly assigned to experimental groups: honest nonclinical, uncoached feigning, and coached feigning. 50 randomly selected individuals with depression from the PAI-A clinical standardization sample were included as the honest clinical group. Sample demographics included a mean age of 16.64 years; 51.2% young men, 48.2% young women; 85.4% Caucasian, 6.7% African American, 5.5% Hispanic, and 2.4% Asian. 80% of feigning profiles reported clinical levels of depression. MANOVA results showed strong support for the Rogers Discriminant Function (RDF; d range = 1.85–2.05). The Negative Impression Management (NIM) scale also demonstrated promise (d range = 0.77–1.08), while the smallest effects for detecting feigning were found for the Malingering Index (d range = 0.58–0.70). The negative distortion indices showed good utility in differentiating between groups. Cut-scores and pragmatic implications are presented.

Role of electronic correlation effect on charge ordering in β-V2OPO4

Charge ordering, the ordering of transition metal ions with different oxidation states, is a celebrated feature in mixed valent transition metal oxides, leading to intriguing electronic and magnetic phenomena. In this work, we exploited the electronic and magnetic properties of the charge ordered insulator β-V2OPO4 within the monoclinic C2/c phase by means of first-principles calculations. Our results demonstrated that the AFM-II ordering, in which spin on all V2+ atoms are parallel and so do the spin on all V3+ atoms while these two spin sublattices are antiparallel to each other, experimentally observed, is the magnetic ground state, irrespective of whether the correlation was adopted or not. Furthermore, our theoretical results highlight the importance role of electronic correlation in reasonably reproducing the electronic properties of β-V2OPO4, including the charge ordering, metal-insulator transition, spin orientation as well as structural distortion. The charge ordering scenario has been analyzed in details in terms of Bader charge, magnetic moments, octahedron volume difference and distortion index. In addition, the phase diagram has been established with respect to correlation strengths.

Light distortion of soft multifocal contact lenses with different pupil size and shape

PurposeTo study the light distortion effects of soft multifocal contact lenses and the influence of different pupil size and shape. MethodsA total of 14 eyes of 7 healthy contact lens users (mean age 28.6 ± 8.5 years) were recruited. The “Light Disturbance Analyser” device was employed for light characterization. The selected lenses were the monthly disposable “Biofinity multifocal” (CooperVision, CA, USA), both centre-distance and centre-near designs (addition power +2.50 D). Two circular pupils of 3 mm and 5 mm of diameter, and an elliptical shape (3 horizontal and 5 vertical mm) were used. Metrics such as the light distortion index (LDI), best-fit circle radius and its irregularity were analysed, among others. ResultsThe LDI was generally higher with multifocal lenses, varying from 3.7 ± 0.3 % of the single vision lens to 6.1 ± 3.3 % of the multifocal centre-distance design and the 5-mm pupil. Larger pupils gave higher LDI values, changing from 4.5 ± 2.0 % (3 mm) to 6.1 ± 3.3 % (5 mm) with the centre-distance design. The elliptical pupil produced the largest discrepancy in the distortion size between the vertical and horizontal directions. The centre-distance and centre-near designs behaved similarly in terms of light distortion. ConclusionsThe multifocal contact lenses of the study increased light distortion effects under low light conditions, especially with larger pupils. The shape of the distortion pattern is associated with the shape of the pupil. It seems that not all, but a big percentage of light distortion would be produced by the presence of the out-of-focus images given by a multifocal lens.

Probability distortion, asset prices, and economic growth

In this paper, we link stock market investors’ probability distortion to future economic growth. The empirical challenge is to quantify the optimality of today’s decision making to test for its impact on future economic growth. Fortunately, risk preferences can be estimated from stock markets. Using monthly aggregate stock prices from 1926 to 2015, we estimate risk preferences via an asset pricing model with Cumulative Prospect Theory (CPT) agents and distill a recently proposed probability distortion index. This index negatively predicts GDP growth in-sample and out-of-sample. Predictability is stronger and more reliable over longer horizons. Our results suggest that distorted asset prices may lead to significant welfare losses.

Automated extraction of fine and coarse crackles by independent component analysis

In this work further research was achieved on the separation by Independent Components (IC) of simulated abnormal breathing sounds (ABS) sources immersed in normal breathing sounds. This study considers only ABS discontinuous sounds, known as crackles, and includes fine and coarse types for both inspiratory and expiratory phases. Additionally, we develop a novel proposal to automated characterization of the IC associated with crackles. We analyzed the efficiency of three independent component analysis algorithms, i.e. FastICA, Infomax and TDSEP, through the Amari index, the signal to interference ratio, and the total relative distortion index. In the simulated multichannel signal scenarios, the performance indexes showed that Infomax is the best algorithm to solve the problem of blind source separation, supporting the results found in previous efforts. Finally, the presence of crackles in the IC obtained by Infomax was determined through their kurtosis and skewness, whereas the type of crackle was found by their characterization via the spectrogram of selected IC. Results indicate that the proposed methodology is able to adequately extract the crackle sources and identify the respiratory cycle phase in which they appear. Also, we managed to estimate the type and number of existing crackles in each source. In conclusion, our methodology can provide quantitative information on the clinical relevance of crackles in respiratory patients.

Comparative study of two potential recuperating converters in DC railway electrification system for harmonic mitigation

<span>The regenerative braking energy produced by Light-Rail-Transit (LRT) train is commonly transferred back to power grid via a conventional three-phase inverter (recuperating converter). Although this is a cost saving solution but the ac grid current and voltage waveforms were distorted. Hence passive filters are integrated to mitigate the harmonics. This paper proposed to replace the conventional inverter system with a multilevel converter. Cascaded H-Bridge (CHB) converter and Modular Multilevel Converter (MMC) are selected to be evaluated in this paper due to their modularity structures. The aim of this study is to determine the most potential multilevel converter to be implemented without additional passive filters. Nine-level CHB and nine-level MMC converters are modeled with MATLAB/Simulink simulation tool. Both converters are modulated with Level-Shifted Pulse Width Modulation technique. The output voltage and current waveforms generated by CHB and MMC are presented with full analysis. It is concluded that MMC converter is more suitable to be used as a recuperating converter. It produces a clean voltage and current waveforms. The voltage and current Total Harmonic Distortion (THD) indexes are found approximate to 8% and 3%.</span>

The Effect of Tongue–Jaw Coupling on Phonetic Distinctiveness of Vowels in Amyotrophic Lateral Sclerosis

Purpose The aim of this study was to determine the relation of tongue-jaw coupling to phonetic distinctiveness of vowels in persons at different stages (i.e., early, middle, late) of bulbar motor involvement in amyotrophic lateral sclerosis (ALS) and healthy controls. Method The pattern of spatial tongue-jaw coupling was derived from 11 individuals with ALS and 11 healthy controls using the parallel factor analysis. Two articulatory components, which correspond to tongue displacement independent of the jaw (iTongue) and jaw contribution to tongue displacement (cJaw), were extracted from the composite tongue-jaw displacement. These articulatory components were correlated with F1 (i.e., height) and F2-F1 (i.e., advancement) of 4 vowels (/i/, /u/, /æ/, and /ɔ/) across all participants in each group. In addition, a comprehensive index of functional tongue-jaw coupling was derived as the ratio of cJaw/(iTongue + cJaw), and an acoustic index of vowel distortion (VowelDis) was derived to quantify the overall disease-related changes in phonetic distinctiveness of vowels. Based on these indices, disease-related changes in tongue-jaw coupling and phonetic distinctiveness of vowels were examined in individuals at the early, middle, and late stages of the disease. Results For healthy controls, both iTongue and cJaw contributed to F2-F1, while only cJaw contributed to F1. For individuals with ALS, both iTongue and cJaw contributed to F1, whereas only cJaw contributed to F2-F1. Disease-related changes in tongue-jaw coupling included (a) an overall decrease of the percent contribution of the tongue to the composite tongue-jaw displacement accompanied by an increase of percent contribution of the jaw and (b) several changes in the direction of tongue and jaw displacements occurred at different stages of the disease. These disease-related changes in tongue-jaw coupling had various impacts on phonetic distinctiveness of vowels, resulting in (a) a backward shift of front vowels and reduced front-back vowel contrasts, which occurred early and throughout the disease stages; (b) raising of all vowels during the middle stage of the disease; and (c) reduced high-low vowel contrasts during the late stage of the disease. Overall, phonetic distinctiveness of vowels deteriorated progressively throughout the disease course. Conclusions Different from healthy controls who established optimal functional coupling between the tongue and the jaw during vowel productions, individuals at the early-to-middle stages of bulbar ALS showed various adaptive changes in tongue-jaw coupling in response to the disease-related biomechanical and muscular changes in the articulators (particularly in the tongue). These adaptive changes in tongue-jaw coupling were found to be partially effective in mitigating the negative effect of articulatory involvement on phonetic distinctiveness of vowels. As the disease progressed to the late stage, such adaptations appeared to be no longer evident, resulting in a substantial overall reduction of vowel contrasts.

Regional Competition in China under the Price Distortion of Construction Land: A Study Based on a Two‐regime Spatial Durbin Model

AbstractThis study examines regional competition in China by considering the spatial correlation and spillover effect of construction land price distortion using a two‐regime Spatial Durbin Model to investigate the patterns and trends of the competition between 285 cities in China from 2006 to 2015. The study finds: (i) price distortion of construction land is a common phenomenon but the distortion index generally shows a declining trend; (ii) regional competition through construction land price distortion shows a weakly intensified pattern, although the competition patterns in the four regions of China varied; and (iii) the intensity of competition between regions was lower during the 12th Five‐year Plan compared to the 11th Plan. The intensity of competition between cities was also lower inside than outside urban agglomerations. These results provide policy implications for remedying the price distortion of construction land and promoting regional coordinated development.

Low gamma shift blue-phase liquid crystal display with electric field induced multi-domain electrode structure

ABSTRACTTo reduce the gamma shift of blue-phase liquid crystal display (BPLCD), the multi-domain electrode structure with four sub-electrodes is proposed. The effects of electrodes’ parameters on electro-optical curve and gamma shift are calculated, and the gamma shift and contrast ratio at full viewing-cone are also investigated. For the proposed protrusion BPLCD, the operating voltage is reduced by ~73%, and the transmittance is increased by ~20% compared with the conventional in-plane switching BPLCD. The results also show that the off-axis image distortion index can be reduced from 0.4318 to 0.0875 at the polar angle of 60°, and it works well under various electrodes’ sizes. Moreover, the indistinguishable gamma shift can be obtained at full viewing-cone for the proposed BPLCD, and the uniform light distribution and high contrast ratio can be obtained as well.

Numerical Simulation of the Performance of a Twin Scroll Radial Turbine at Different Operating Conditions

Twin scroll radial turbines are increasingly used for turbocharging applications, to take advantage of the pulsating exhaust gases. In spite of its relevance in turbocharging techniques, scientific literature about CFD applied to twin scroll turbines is limited, especially in case of partial admission. In the present paper a CFD complete model of a twin scroll radial turbine is developed in order to give a contribution to literature in understanding the capabilities of current industrial CFD approaches applied to these difficult cases and to develop performance index that can be used for turbine design optimization purposes. The flow solution is obtained by means of ANSYS CFX ® in a wide range of operating conditions in full and partial admission cases. The total-to-static efficiency and the mass flow parameter (MFP) have been calculated and compared with the experimental database in order to validate the numerical model. The purpose of the developed procedure is also to generate a database for twin scroll turbines useful for future applications. A comparison between performances obtained in different admission conditions was performed. In particular the analysis focused on the characterization of the flow at volute outlet/rotor inlet section. A flow distortion index at rotor inlet was introduced to correlate the turbine performance and the flow nonuniformities generated by the volute. Finally the influence of the backside cavity on the performance parameters is also discussed. The introduction of these new nonuniformity indices is proposed for volute design and optimization procedures.

A parallel evaluation of the wind and wave energy resources along the Latin American and European coastal environments

Considering the trend to develop renewable projects in marine environment, the objective of the present work is to provide a comprehensive picture of the wind and wave energy for some significant coastal sites from Latin America and Europe. Thus, a reanalysis database that covers 17 years of wind and wave data (2000–2016) is considered, evaluating also some statistical parameters. In this way, we identified the most interesting sites for a marine project. At the same time, the performance of five wind turbines (Senvion 6.2M 126, BARD 5.0, SWT–3.6 –120, Vestas V90–3.0 and Vestas V80–2.0) and five wave energy converters (Wave Dragon, PPC, Pelamis, Aqua Buoy, Seabased AB) is also assessed. The results show that in Latin America, the coastal region located close to Tierra del Fuego presents the best wind resources, indicating a maximum wind power value of 1759 W/m2 (at 80 m height). This is relatively similar to the conditions encountered at the Carloway site, in Europe close to Ireland (1778 W/m2). As regards wave power, a maximum value of 82.59 kW/m is assessed for the Carloway site. According to the total harmonic distortion index, the best sites to develop a joint wind-wave project are in Latin America, where for this index most of the values are below the 0.8 limit. Looking at the performances of wind and wave generators, we notice a maximum power output of 4.26 MW for the Senvion 6.2M 126 turbine, compared to an expected electric power of 2.64 MW, which results for the Wave Dragon energy converter. The results show that the capacity factors of the wave systems are significantly smaller than in case of the wind turbines.

Flow field behind a complex total pressure distortion screen

The flow field behind a complex total pressure distortion screen is investigated experimentally and numerically. The distortion screen is designed using an established design methodology and fabricated by water-jet cutting technique. The distorted total pressure field behind the screen is quantified by a distortion index parameter, which is evaluated from computations and experiments for several values of inlet Mach number. The root-mean-square error between the target total pressure values and that achieved by the screen design at the aerodynamic interface plane is 4.75%. The evolution of the distorted total pressure field downstream of the screen is presented in detail in terms of radial and circumferential total pressure distributions and their gradients. An alternative interpretation of the distorted total pressure field is made by means of defining a total pressure flux existing behind the screen and expanding it using derivative-moment transformation technique. It is seen that the circumferential vorticity is a major contributing factor to the total pressure flux.

Study on thermal-lens induced mode coupling in step-index large mode area fiber lasers.

In this paper, the thermal-lens induced mode coupling in step-index large mode area fiber laser is systematically investigated. The pertinent mode coupling coefficient is studied firstly, to the best of our knowledge. It is demonstrated that the mode coupling can be induced by the thermal-lens induced waveguide changing along the active fiber. It is found that the mode coupling can be enhanced mainly by the thermally-induced mode distortion and refractive index variation, both of which will become severe with the large thermal load. The impacts of fiber configuration parameters on the mode coupling are discussed. It is found that in the straight fiber, the mode coupling in a larger-core fiber can be weakened when the thermal load is low, but it will become stronger when thermal-lens effect is severe enough. However, in the bent fiber, enlarging core size, reducing core numerical aperture (NA), or decreasing bend radius will all aggravate the mode coupling. Especially when NA is excessively reduced, the mode coupling will be dramatically raised even with a small thermal load. The pertinent study is significant for understanding the mode coupling phenomenon in high-power fiber lasers.

Numerical Investigations of S-Shaped Air Inlet for Embedded Engines

In this paper, compressible Reynolds-averaged Navier–Stokes computations are conducted for an S-shaped duct, in a clean configuration and also with a single row of vortex generators. The numerical simulations are performed using a hybrid unstructured grid. The influence of including the geometric representation of the probe instrumentation is investigated by considering the rake fairing geometry and also the geometry of the complete rake with the probes. Some aspects of the probe modeling are also discussed. A direct comparison of the numerical simulation results with the experimental values is performed for the wall static pressure along the duct, total pressure recovery, and distortion indices at the aerodynamic interface plane. Three different eddy-viscosity turbulence models are evaluated: the one-equation Spalart–Allmaras, and the two-equation realizable and shear stress transport. A virtual 200-probe rake is also proposed, beyond the standard 40-probe rake, to enrich the total pressure and distortion indices comparisons. An overall good agreement is observed among experimental results and the numerical wall static pressure and the total pressure topology at the aerodynamic interface plane. Some discrepancies for the distortion indices are verified and discussed in detail.

Structure and Magnetic Properties of Bulk Synthesized Mn2−xFexP1−ySiy Compounds from Magnetization, 57Fe Mössbauer Spectroscopy, and Electronic Structure Calculations

The series of Mn2−xFexP1−ySiy types of compounds form one of the most promising families of magnetocaloric materials in term of performances and availability of the elemental components. Potential for large scale application needs to optimize the synthesis process, and an easy and rather fast process here described is based on the use of two main type of precursors, providing the Fe-P and Mn-Si proportions. The series of Mn2−xFexP1−ySiy compounds were synthesized and carefully investigated for their crystal structure versus temperature and compared interestingly with earlier results. A strong magnetoelastic effect accompanying the 1st order magnetic transition—as well as the parent phosphide–arsenides—was related to the relative stability of both the Fe magnetic polarization and the Fe–Fe exchange couplings. In order to better understand this effect, we propose a local distortion index of the non-metal tetrahedron hosting Fe atoms. Besides, from Mn-rich (Si-rich) to Fe-rich (P-rich) compositions, it is shown that the magnetocaloric phenomenon can be established on demand below and above room temperature. Excellent performance compounds were realized in terms of magnetic entropy ΔSm and adiabatic temperature ΔTad variations. Since from literature it was seen that the magnetic performances are very sensitive to the synthesis process, correspondingly here a new effective process is proposed. Mössbauer spectroscopy analysis was performed on Mn-rich, equi-atomic Mn-Fe, and Fe-rich compounds, allowing determination of the distribution of hyperfine fields setting on Fe in the tetrahedral and pyramidal sites, respectively. Electronic structure calculations confirmed the scheme of metal and non-metal preferential ordering, respectively. Moreover, the local magnetic moments were derived, in fair agreement with both the experimental magnetization and the Fe contributions, as determined by Mössbauer spectroscopy.

Distortion and magnification of four digital cephalometric units.

To assess the validity of using the calibration ruler for correcting magnification of linear measurements and to explore and compare the vertical and horizontal magnification of four digital cephalometric units. An acrylic box was imaged at seven sagittal positions using four digital cephalometric units: Orthopantomograph OC100, Orthopantomograph OC200, Sirona Orthophos CD, and Sirona Orthophos DS. The true linear lengths of the phantom, corrected, and uncorrected linear lengths on the images were measured and compared. The validity of measurements using the calibration ruler was assessed. The magnification values and distortion indices were calculated and compared among the four cephalometric units. For linear measurements on the mid-sagittal plane and averaged linear measurements on bilateral symmetric sagittal planes, the bias 1.96 STD of the calibration ruler ranged from 1% to 2% for the four cephalometric testing units. For linear measurements on the single lateral sagittal plane, the bias 1.96 STD ranged from 3% to 6%. The vertical scanning charge-coupled device cephalometric unit produced the greatest distortion, ranging from 1.029 to 0.964. The metal millimeter calibration ruler is an accurate reference for linear measurement magnification correction. Because of unpredictability and machine specificity, the magnification and distortion of a cephalometric unit should be calibrated for the estimation of cephalometric measurement error.

Generalized stacking fault energies of Cr23C6 carbide: A first-principles study

In many high temperature-resistant Ni-based superalloys, M23C6 carbides form during processing and remain as non-metallic inclusions during the materials use in application. M23C6 type inclusions are principal sites for potential fatigue crack initiation, thus the accurate quantification of their energy barriers for deformation is necessary for in-depth understanding of the overarching mechanical behavior of the material system. In this study, the generalized stacking fault energies (GSFE) are theoretically determined for chromium-rich types of M23C6 carbides (i.e., Cr23C6) in two prominent slip systems: {1 1 1}〈112¯〉 and {1 1 1}〈101¯〉. The results present GSFE curves with double saddle points in both slip systems. The double saddle points of the GSFE curves are explained via the electronic structure of atoms near the slip plane. At deformation quantified by half of a Burgers vector (i.e., 0.5 bp), a pentacyclic charge density distribution appears representing a local minimum energy configuration, which results in a valley of the GSFE curve. Furthermore, the effective coordination number (n) and the distortion index (Δd) of the coordination polyhedrons are employed to characterize the structural change. The analysis reveals that the values of the indexes n and Δd at a displacement value of 0.5 bp are close to the values of a perfect Cr23C6 crystal, while comparatively the distortion index is higher at the saddle points. These results provide new insights into the deformation pathways of M23C6 carbides.