Distortion Level Research Articles

The Relationship Between Cognitive Distortions and School Bullying in Jerusalem Suburbs’ Schools

Objectives: The study identifies the relationship between cognitive distortions and bullying in schools in the suburbs of Jerusalem. Methods: The study used a stratified sample of 250 students who study in schools located in the suburbs of Jerusalem and whose ages range from 15 to 18 years old. The Cognitive Distortions Scale and the School Bullying Scale were used as instruments for data collection after verifying their validity and reliability. Results: The results indicated that the mean score for cognitive distortions is moderate whereas the mean score for school bullying is low. Statistically significant differences were observed in the levels of cognitive distortions based on gender, with higher levels in males. Additionally, the results showed statistically significant differences in the levels of cognitive distortions and school bullying based on students’ grades, favoring students with lower grades. However, there were no statistically significant differences based on the grade level of participants. The study also identified a weak positive correlation between cognitive distortions and school bullying. Conclusion: By shedding light on the intricate relationship between cognitive distortions and school bullying, the study stresses the significance of developing educational and psychological strategies to address these challenges. Hence, it emphasizes the need for customized interventions in schools to deal with cognitive distortions and bullying, focusing on gender differences.

Advanced Harmonic Analysis in Industrial Power Systems: Its Impact on Enhancing Power Quality and System Performance

This paper presents an advanced harmonic analysis of industrial power systems, focusing on its impact on enhancing power quality and system performance. The study investigates the harmonic distortions caused by nonlinear loads, particularly those introduced by Variable Frequency Drives (VFDs), in a manufacturing plant. Measurements of key electrical parameters, such as voltage, current, and Total Harmonic Distortion (THD), were recorded and analysed. The results reveal significant harmonic distortion levels, exceeding industry standards, which can lead to reduced equipment efficiency and potential damage. By adhering to IEEE 519 guidelines and implementing harmonic mitigation strategies, such as filters and power factor correction, the paper demonstrates how power quality can be improved. The findings provide a foundation for future simulation and optimization efforts aimed at reducing harmonic distortion and enhancing system performance. Keywords: Total Harmonic Distortion (THD), Harmonic Analysis, Power Quality, Industrial Power Systems, Current Distortion.

Influence of the shock wave-turbulence interaction on the swirl distortion in hypersonic inlet

This study uses the Large Eddy Simulation (LES) technique to conduct an exhaustive analysis of the flow characteristics within the Rectangular-to-Elliptical shape Transition (REST) inlet under Mach 6 conditions. It mainly focuses on investigating the influence of the shock wave-turbulence interaction on the swirl distortion at the inlet exit. At the design condition, characterized by 0° Attack and 0° Sideslip, the incident shock wave at the inlet lip undergoes multiple reflections within the boundary layer of the domain wall, culminating in the formation of turbulent structures. The first reflected shock wave has the highest energy, exerting a significant impact on the boundary layer and the exit swirl distortion. On the contrary, the energy of the incident shock wave is progressively reduced due to repeated reflections, which results in reducing the exit swirl distortion. Under off-design conditions, characterized by 6° Attack and 0° Sideslip as well as 6° Attack with 6° Sideslip, variations in the incoming flow make the incident shock wave move inward, decreasing the frequency of shock wave reflections and even significantly reducing the reflected shock waves under conditions of 6° Attack and 6° Sideslip. However, this results in significantly increasing the exit swirl angle and distortion intensity. The obtained results demonstrate that changes in the incoming flow conditions significantly affect the level of exit swirl distortion by modulating the shock wave-turbulence interaction, especially in terms of the positioning of the incident shock wave and the quantity of reflected shock waves. In addition, this paper studies the wall heat transfer coefficient of the inlet. The obtained results show that the interaction between shock waves and the boundary layer significantly affects the heat transfer coefficient. This study provides a foundation for the comprehension and prediction of the performance of hypersonic inlets across a spectrum of flight conditions, and for the guidance of the design and optimization of such inlets.

Engagement in New Gambling Practices and its Association with Gambling Disorder, Impulsivity, and Cognitive Distortions: Findings from a Nationally Representative Sample of Spanish Gamblers.

Most epidemiological surveys focus on adult gambling behaviors related to traditional gambling forms, while studies on novel forms often focus on loot boxes and cryptocurrency trading individually. This study examines the co-ocurrence of emergent gambling and gambling-like practices, analyzing the demographic and psychological characteristics of involved gamblers. A cross-sectional study surveyed 1429 Spanish individuals aged 18-65, using a web-based questionnaire. The survey assessed participation in 19 gambling (e.g., lotteries, sports betting) and gambling-like activities (e.g., trading of cryptocurrencies and other assets, buying loot-boxes), along with sociodemographic and substance use. Problem gambling (PGSI), Impulsivity (UPPS-P), and cognitive distortions (Labrador's cognitive distortions scale) were also assessed. Participants who gambled over the past year (n = 921) were classified into four groups: traditional gambling (TG) only (64.5%, n = 594), TG with trading activities (27.5%, n = 253), TG with gambling withing video games or streaming platforms (2.5%, n = 23), and TG with both trading and video gambling (5.5%, n = 51). Most gamblers engaged exclusively in traditional formats, but 35.5% also participated in novel gambling forms. Those involved in both trading and video gambling were generally younger, male, with higher levels of impulsivity and gambling-related cognitive distortions compared to TG-only gamblers (p < 0.001). This group also exhibited higher rates of problem gambling and substance use (p < 0.001). This study emphasize the importance of including emerging gambling activities, which are particularly prevalent among high-risk gamblers, in epidemiological surveys. Identifying new gambling patterns and associated risk factors could help optimize public policies and develop more effective regulatory and prevention strategies.

Lack of visual experience leads to severe distortions in the hand representation of the body model

This study investigates the impact of vision on the maintenance of hand representation in the implicit body model, particularly focusing on congenitally blind individuals. To address this, we performed a hand landmark localization task on blind individuals who lacked visual experience of their bodies and compared their performance to normally sighted and normally sighted but blindfolded participants. Through measurements of finger lengths, hand width, and shape index, we demonstrate that blind participants exhibit significantly greater distortions in their hand representation compared to sighted and blindfolded controls. Notably, blind individuals displayed a marked overestimation of hand width and an underestimation of finger lengths, particularly in digits D2, D3, and D4. Surprisingly, blind subjects with partial vision displayed more severe distortions than those with no residual vision. Furthermore, our findings reveal that late-blind participants exhibit similar levels of distortion as congenitally blind individuals, suggesting an extended period of susceptibility to the lack of visual input in shaping body representations. The Reverse Distortion (RD) hypothesis provides a plausible explanation for these distortions, suggesting that compensatory mechanisms occur within the body model to counteract the anisotropic cortical representations. Our results support this hypothesis: blind individuals have expanded cortical representations processing tactile information, so this could lead to more pronounced distortions in their hand representation of the body model. This underscores the importance of visual input in modulating body representations. Overall, our study highlights the malleability of body representations and the intricate interplay between sensory inputs and cortical processing in shaping the implicit body model.

Technical Development and In Silico Implementation of SyntheticMR in Head and Neck Adaptive Radiation Therapy: A Prospective R-IDEAL Stage 0/1 Technology Development Report.

The purpose of this study was to investigate the technical feasibility of integrating the quantitative maps available from SyntheticMR into the head and neck adaptive radiation oncology workflow. While SyntheticMR has been investigated for diagnostic applications, no studies have investigated its feasibility and potential for MR-Simulation or MR-Linac workflow. Demonstrating the feasibility of using this technique will facilitate rapid quantitative biomarker extraction which can be leveraged to guide adaptive radiation therapy decision making. Two phantoms, two healthy volunteers, and one patient were scanned using SyntheticMR on the MR-Simulation and MR-Linac devices with scan times between four to six minutes. Images in phantoms and volunteers were conducted in a test/retest protocol. The correlation between measured and reference quantitative T1, T2, and PD values were determined across clinical ranges in the phantom. Distortion was also studied. Contours of head and neck organs-at-risk (OAR) were drawn and applied to extract T1, T2, and PD. These values were plotted against each other, clusters were computed, and their separability significance was determined to evaluate SyntheticMR for differentiating tumor and normal tissue. The Lin's Concordance Correlation Coefficient between the measured and phantom reference values was above 0.98 for both the MR-Sim and MR-Linac. No significant levels of distortion were measured. The mean bias between the measured and phantom reference values across repeated scans was below 4% for T1, 7% for T2, and 4% for PD for both the MR-Sim and MR-Linac. For T1 vs. T2 and T1 vs. PD, the GTV contour exhibited perfect purity against neighboring OARs while being 0.7 for T2 vs. PD. All cluster significance levels between the GTV and the nearest OAR, the tongue, using the SigClust method was p < 0.001. The technical feasibility of SyntheticMR was confirmed. Application of this technique to the head and neck adaptive radiation therapy workflow can enrich the current quantitative biomarker landscape.

Research on the bonding performance and mechanism of hot-rolled Ti/steel clad plates based on surface state

The interfacial bonding strength of Ti/steel clad plates is a crucial factor that affects their application. However, the effect of the surface state, which is a significant determinant, is often neglected. In this study, various surface treatment processes were employed to create different surface states based on the hot-rolling of double-layer steel billets, and the effects and mechanisms of these surface states on the bonding performance of hot-rolled Ti/steel clad plates were systematically examined. The results showed that the Ti/steel clad plates pretreated with a louver wheel exhibited the highest bonding performance, with the average bonding strength peaking at 328.67 MPa and stabilising at approximately 300 MPa. This strength was approximately 50 % greater than that achieved with wire brush treatment and significantly surpassed the results obtained with sanding belts and diamond grinding discs. The analysis of the surface properties and microstructural characteristics revealed that various surface treatments led to different levels of work hardening and lattice distortion at the surface, and the interface bonding strength depended on the degree of matching between these factors. Proper surface hardening can promote the transformation of lattice distortion energy into a diffusion-driving force of elements on both sides of the interface during rolling, enabling sufficient diffusion of elements on both sides of the interface and obtaining good interface bonding performance. A phenomenological prediction mechanism-based model was established to quantify the relationship between the surface state and the bonding strength. This study elucidats the mechanism by which the surface state of materials influences the interfacial bonding performance of hot-rolled Ti/steel clad plates. These findings have significant implications for enhancing the interfacial properties of these composite plates and for selecting suitable pre-rolling surface treatment processes.

Criminal Histories, Risk Profiles, and Predictors of Recidivism Among Men Who Sexually Offend Over the Age of 60 Years

Research has consistently found sexual recidivism risk drops as men convicted of sexual offenses age, but little research exists on those few men who do sexually offend when older. The current study examined the criminal histories, risk profiles, and predictors of sexual recidivism in a large sample of men who sexually offended over the age of 60 years. Analyses showed low levels of sexual offending under the age of 60 years prior to the commission of a sexual offense over the age of 60 years, with only 27% of the sample having sexually offended under 60 years. Examination of the risk profiles of the sample evidenced high levels of possible deviant sexual attraction and sexual cognitive distortions, which restricted the range on these variables, and limited their ability to predict sexual recidivism. Instead, nonsexual risk factors and protective factors appeared better predictors of sexual recidivism for men who have sexually offended over the age of 60 years.

Harmonic State Estimation in Power Systems Using the Jaya Algorithm

The increasing use of nonlinear loads in power systems introduces voltage and current components at non-fundamental frequencies, leading to harmonic distortion, which negatively impacts electrical and electronic devices. A common mitigation strategy involves identifying harmonic sources and installing filters nearby. However, due to the high cost of power quality (PQ) meters, comprehensive harmonic level monitoring across the entire power system is impractical. To address this, various methodologies for Harmonic State Estimation (HSE) have been developed, which estimate distortion levels on unmonitored system buses using data from a minimal set of monitored ones. Many HSE techniques rely on optimization algorithms with numerous tuning parameters, complicating their application. This paper proposes a novel methodology for fundamental frequency power flow and harmonic state estimation using the Jaya algorithm, which is characterized by fewer tuning parameters for easier adjustment. It also introduces a strategy to determine the minimal number of buses that need monitoring to achieve system observability. The methodology is validated on the IEEE-14 and IEEE-30 bus systems, demonstrating its effectiveness. The results of the proposed methodology are compared with those obtained using Evolutionary Strategies (ESs), highlighting its enhanced accuracy and computational efficiency.

Performance analysis of a new single-phase transformerless PV inverter structure based on a buck-boost converter

A single-phase inverter based on a buck-boost converter is increasingly used in modern power electronics, particularly in solar photovoltaic systems. Unlike traditional inverters that utilize transformers to electrically isolate the solar system from the power grid, this transformerless design enhances efficiency, reduces weight, and lowers costs. However, the absence of a transformer introduces challenges related to Electromagnetic Compatibility (EMC) and the potential for increased leakage currents, which must be carefully managed to ensure system safety and performance. In this paper, the performances of a new configuration of a single-phase transformerless PV inverter based on a dc-dc buck-boost converter is proposed and analyzed. Since it is the only switch (mosfet) in the DC-DC converter that operates at high frequency, and it is controlled by pulse width modulation (PWM) to adjust the output voltage. This allows for flexible voltage conversion, enabling the inverter to either step up (boost) or step down (buck) the input voltage as needed. Therefore, switching losses can be significantly reduced to improve efficiency and reduce electromagnetic interference of the single-phase inverter structure. In order to demonstrate the EMC performances and evaluate the leakage current of the proposed structure, an EMC model is developed under the Simscape-MATLAB/Simulink environment, this model offers an EMC analysis including the prediction of leakage current over a frequency range from 100 Hz to 2 MHz. The results clearly showed that the level of the Total harmonic distortion (THD), as well as the levels of leakage current, are below the requested EMC standards.

Cognitive Distortion Scale for Bangladesh: Development and Properties

The purpose of the study was to develop a scale for assessing cognitive distortions in Bangladesh and establishing psychometric properties for Bangladeshi population. The scale was named as Bangladesh Cognitive Distortion Scale (BCDS). Items were constructed through three stages of intensive expert evaluation where 128 respondents participated and both item analysis and factor analysis were undertaken. Finalized BCDS with 39 items was administered to 478 respondents to calculate its psychometric properties. Concurrent validity of BCDS was found 0.828 by calculating correlation between the score of BCDS and clinician’s subjective rating. Predictive validity considering anxiety and depression scale was found 0.756 and 0.841, respectively. Convergent validity (0.670) was confirmed through the correlation between the DAS and BCDS and divergent validity was established by the discriminate value (F=649.564, α&lt;0.01) of clinical and non-clinical groups. Internal consistency reliability of BCDS (Cronbach Alpha- 0.962 and test-retest- 0.890) was found very high. The cut-off point for measuring cognitive distortion by BCDS was found 56 with sensitivity 87% and specificity 88%. According to the percentile norm, total score 56 to 72, 73 to 91, 92 to 109, 110 and above represents the mild, moderate, severe, and profound levels of cognitive distortions respectively. BCDS not only will help both clinicians and researchers to assess cognitive distortions within a short time but also could be used as a valid and reliable outcome measure in cognitive behavior therapy. Dhaka Univ. J. Biol. Sci. 33(2): 97-109, 2024 (July)

Scattering matrix similarity metric optimization for improved defect characterisation based on dynamic graph attention networks

Ultrasonic scattering matrices contain rich defect information and have great potential for characterising small crack-like defects. However, experimentally measured scattering matrices often exhibit some level of distortions compared to those of the idealised defects, posing challenges for accurate defect characterisation. In this paper, defect characterisation was performed by adopting a nearest neighbour approach based on a scattering matrix database of reference defects, and the test data were contaminated by coherent measurement noise of varying amplitudes. The performance of different similarity metrics on characterisation accuracy was studied, including the Euclidean similarity, cosine similarity, Pearson correlation coefficient, and the structural similarity index. Based on a comprehensive analysis of the strengths and weaknesses of different similarity metrics, we propose a defect characterisation framework by constructing similarity graphs and leveraging advanced graph neural networks. Within the proposed approach, multiple metrics were adopted to quantify the similarity between the scattering matrices of different defects, and an improved dynamic graph attention network was developed based on a customised neighbour sampling strategy to learn the optimal metric from the graph-structured data. Experimental results show that compared to the conventional approach which adopted a globally optimal similarity metric, the proposed method can reduce the root mean squared error for the length and angle predictions by 60.5% and 67.1%, respectively.

A Minimal Nontrivial Example of Higher Order Evidence.

Higher order evidence (evidence about evidence) allows epidemiologists and other health data scientists to account for measurement error in validation data. Here, to illustrate the use of higher order evidence, we provide a minimal nontrivial example of estimating the proportion and show how higher order evidence can be used to construct sensitivity analyses. The proposed method provides a flexible approach to account for multiple levels of distortion in the results of epidemiologic studies.

A Comparative Study of Cognitive Distortion among Mild and Severe Migraine Patients

Migraine is a kind of headache which induced various types of problems in patients. Cognitive distortion is one the worst impact of migraine. The term cognitive distortion refers the individual’s negative thoughts towards their environment. The aim of this research is to know the level of migraine and its impact on cognitive distortion. 62 migraine patients were selected from different hospitals of Ranchi. The Migraine Disability Assessment Test (MIDAS) was applied to know the severity level of migraine and Cognitive Distortion Scale (CDS) was applied to know the cognitive distortion in patients. After analysis of data it was found that the number of severe migraine patients was higher and they have higher level of cognitive distortion.

Design of a optimal robust adaptive neural network-based fractional-order PID controller for H-bridge single-phase inverter

Adaptive Neural Network- based Fractional-order PID Control (NN-FO-PID) approach is designed for H-bridge inverter. This inverter has an LC filter to decrease the level of Total Harmonic Distortion (THD) that can affect the efficiency of the system. In addition, the reduction of THD and stability insurance of the filter are challenging performances. To fulfill this function, a fractional order proportional integrated derivative (FO-PID) controller is developed for the inverter. A few merits of the Fractional-Order notion as a useful technique include reduced sensitivity to noise and parametric fluctuation; however, for a wider range of disturbances, such as noise, this approach shows an unsuitable practical application based on its fixed gain values. Moreover, having parameters uncertainties including parametric variations, load uncertainty, supply voltage variation uplifts this challenging condition severely, and the parameters need to be adjusted once more for more dependable operations. As a result, the control parameters must be optimized once more to provide ideal operations. Here, an adaptive mechanism is proposed based on neural network structure to optimize the gains of the FO-PID controller for better performances. In real applications, this approach has some benefits, since it uses the Black-box technique, which does not necessitate a precise mathematical model of the system, resulting in a reduced computational burden, simple implementation, and reduced dependence on the model’s states. Even under extremely difficult circumstances, the artificial neural network structure effectively optimizes the FO-PID gains in real-time. This benefit can reduce the amount of THD-level for the inverter, properly. Additionally, to have a proper response in the first step condition, and trying to reduce the level of dangerous conditions, based on benefits of the ant lion optimization method, it is considered to select the initial values of the FO-PID controller gains. Here to verify the superiority of the proposed controller, PID and FO-PID controllers are offered to drive a comparison with this method, which are optimized using the PSO optimization algorithm. The analysis of simulation data shows that the suggested control strategy is appropriate for maintaining stability as well as adequately compensating for disturbances and uncertainties in the inverter. Furthermore, with the help of this controller, THD level decreased lower than 2 percent.

Neural Network Equalisation for High-Speed Eye-Safe Optical Wireless Communication with 850 nm SM-VCSELs

In this paper, we experimentally illustrate the effectiveness of neural networks (NNs) as non-linear equalisers for multilevel pulse amplitude modulation (PAM-M) transmission over an optical wireless communication (OWC) link. In our study, we compare the bit-error-rate (BER) performances of two decision feedback equalisers (DFEs)—a multilayer-perceptron-based DFE (MLPDFE), which is the NN equaliser, and a transversal DFE (TRDFE)—under two degrees of non-linear distortion using an eye-safe 850 nm single-mode vertical-cavity surface-emitting laser (SM-VCSEL). Our results consistently show that the MLPDFE delivers superior performance in comparison to the TRDFE, particularly in scenarios involving high non-linear distortion and PAM constellations with eight or more levels. At a forward error correction (FEC) threshold BER of 0.0038, we achieve bit rates of ~28 Gbps, ~29 Gbps, ~22.5 Gbps, and ~5 Gbps using PAM schemes with 2, 4, 8, and 16 levels, respectively, with the MLPDFE. Comparably, the TRDFE yields bit rates of ~28 Gbps and ~29 Gbps with PAM-2 and PAM-4, respectively. Higher PAM levels with the TRDFE result in BERs greater than 0.0038 for bit rates above 2 Gbps. These results highlight the effectiveness of the MLPDFE in optimising the performance of SM-VCSEL-based OWC systems across different modulation schemes and non-linear distortion levels.

Reverse Thrust Aerodynamics of Variable Pitch Fans with Inlet Distortion

Abstract Variable pitch fans can improve the operability of low pressure ratio fan systems by re-pitching the rotor blades. If a variable pitch fan can generate sufficient reverse thrust on landing it also eliminates the need for heavy, cascade-type thrust reversers. However, any reverse thrust generation is impacted by high levels of inlet distortion generated as air is drawn into the exhaust nozzle. This paper uses RANS computations and low-speed rig experiments to explore how a representative inlet distortion from the engine installation affects the aerodynamics and performance of a variable pitch fan operating in reverse thrust mode. The simulations and the experiments show that the distortion from the engine installation leads to a highly three-dimensional flow field with a large recirculation region within the bypass duct. The distortion substantially redistributes the mass flow, thrust and power in the engine. Streamline tracking combined with a power balance analysis reveals highly radial flow within the fan rotor, with almost all the fan power used to drive the recirculating flow in the bypass duct, generating high loss and high total temperature. The recirculation reduces the net mass flow through the engine to around 5% of a uniform inflow case and greatly reduces the effective reverse thrust. With uniform inflow, the net reverse thrust was found to be 35% of the nominal takeoff thrust. With inlet distortion, this was reduced to 20%. This demonstrates the importance of designing and operating variable pitch fan systems to minimise reverse thrust inlet distortion.

Correcting angular distortions in Bragg coherent X-ray diffraction imaging.

Bragg coherent X-ray diffraction imaging (BCDI) has emerged as a powerful technique for strain imaging and morphology reconstruction of nanometre-scale crystals. However, BCDI often suffers from angular distortions that appear during data acquisition, caused by radiation pressure, heating or imperfect scanning stages. This limits the applicability of BCDI, in particular for small crystals and high-flux X-ray beams. Here, we present a pre-processing algorithm that recovers the 3D datasets from the BCDI dataset measured under the impact of large angular distortions. We systematically investigate the performance of this method for different levels of distortion and find that the algorithm recovers the correct angles for distortions up to 16.4× (1640%) the angular step size dθ = 0.004°. We also show that the angles in a continuous scan can be recovered with high accuracy. As expected, the correction provides marked improvements in the subsequent phase retrieval.

Comparative Evaluation of the Performance of a Mobile Device Camera and a Full-Frame Mirrorless Camera in Close-Range Photogrammetry Applications.

The comparative evaluation of the performance of a mobile device camera and an affordable full-frame mirrorless camera in close-range photogrammetry applications involves assessing the capabilities of these two types of cameras in capturing images for 3D measurement purposes. In this study, experiments are conducted to compare the distortion levels, the accuracy performance, and the image quality of a mobile device camera against a full-frame mirrorless camera when used in close-range photogrammetry applications in various settings. Analytical methodologies and specialized digital tools are used to evaluate the results. In the end, generalized conclusions are drawn for using each technology in close-range photogrammetry applications.

A Web-Based Interactive Application to Simulate and Correct Distortion in Multibeam Sonars

Multibeam sonars are advanced scientific tools for estimating fish school volume and density, using multiple beams to provide comprehensive size measurements of detected targets. However, challenges remain in accurately estimating target dimensions due to beam geometric expansion and overlap, particularly in athwart-beam measurements, which tend to be overestimated with increasing distance from the transducer. We present an interactive web application that simulates distortion caused by beam overlap and expansion in multibeam sonars using simple geometric equations. Users can define sonar characteristics, such as the number of beams, swath opening, or degree of overlap, as well as specify an elliptical target’s dimensions, orientation, and distance from the transducer. The application estimates and visualises the true and distorted shapes of the target, calculating the level of distortion. It can run simulations in both forward and inverse directions, either simulating the distortion of a true school or correcting the shape of a distorted school. This tool aims to enhance the interpretation of multibeam sonar signals and improve the accuracy of target dimension estimates, facilitating more effective use of these sonars in scientific research.