Response Distortion Research Articles

A Comparative Study of Control Methods for Induction Motor and High Performance Z-source Inverter

Design studies of the most suitable controller for the speed of induction motor (SIM) and peak DC-link voltage (PDV) of high performance z-source inverter (HP-ZSI) greatly affects performance of hybrid electric vehicles. This paper is to give comprehensive analyses comparison and evaluations of the different control techniques as PI controller, self-tuning fuzzy PI controller (SFP) and genetic algorithms optimal tuning gains of the PI controller for controlling the SIM based on criteria of the integral of the absolute value of speed error. With control PDV, this paper also presents comparisons of the different techniques as PI controller, fuzzy logic controller, SFP based on observation of its response and total harmonic distortion of current. All methods are applied to the closed loop of the SIM which relies on direct torque control combined with modified space vector modulation and closed loop of PDV in HP-ZSI. These methods are verified by Matlab software. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2445 Full Text: PDF

Measurement issues associated with conditional reasoning tests: An examination of faking

Conditional reasoning (CR) is a new item format that measures personality by indirectly assessing reliance upon the cognitive biases associated with specific traits (James et al., 2005). Previous research suggests that, relative to self-report measures, responses on CR-based measures are more difficult to distort (LeBreton, Barksdale, Robin, & James, 2007). The issue of response distortion in the context of CR-based measures was evaluated in two studies. Study 1 (within-subjects) and Study 2 (between-subjects) both investigated whether responses on a CR-based test of addiction could be faked when indirect assessment was upheld. Results of both studies indicated that, unlike a self-report measure of a similar construct, the CR-based measure was unaffected by response distortion.

Symptom validity assessment in neuropsychology

Purpose – The paper aims to give an introduction into symptom validity assessment (SVA) to non‐experts in the field of neuropsychology.Design/methodology/approach – The analysis is based on the knowledge of the progress in this field which can be conceived as one of the most prolific developments in forensic neuropsychological assessment.Findings – By its very nature, clinical neuropsychology is a data‐driven discipline, both on the level of single‐case assessment and in research. In forensic contexts where secondary gain is immanent, uncooperativeness and malingering may threaten the integrity of data, so much so that no valid conclusions may be drawn from the data.Originality/value – In the last 20 years, clinical and forensic neuropsychologists have been more prominent in the development of methods to detect response distortions and to identify malingering than any other profession. In forensic contexts, neuropsychological evaluations without SVA must be considered incomplete. Clinically and forensical...

‘More shades of grey in my answers’: an interview study revisiting attitude erosion during clerkships

Small declines in patient-centred attitudes during medical education have caused great concern. Although some of the self-report scales applied have solid psychometric foundations, validity evidence for the interpretation of attitude erosion during clerkships remains weak. We sought to address this gap in a qualitative study of the relationships between scores on four commonly used attitude scales and participants' experiences and reflections. Our aim was to gain a better understanding of the score changes from the participants' perspectives. We conducted semi-structured interviews with 15 junior doctors from a cohort (n = 37) that had previously shown a small decline in patient-centred attitudes during clerkships, measured on four self-report scales. In the interviews, we explored interviewees' experiences of their development of patient-centredness and subsequently discussed their scale scores, particularly for those items that contributed to a rise or decline in scores. We analysed the data using a process of constant comparison among personal experiences, scale scores and participants' explanations of score changes, applying the coding techniques of grounded theory. The analysis revealed important response distortions that might be responsible for small declines in scores during clerkships separately from changes in attitudes. The drastic alterations to the participants' frame of reference, attributable to the transition to clinical practice, represented the most prominent cause of distortion. More nuanced, context-specific, patient-centred reasoning resulted in more neutral responses after clerkships, paradoxically causing a decline in scores. In addition to response distortions, the interviews revealed shortcomings in content validity such as an 'extreme' construct of patient-centredness. This study calls into question the validity of the interpretation of attitude erosion during clerkships. The findings suggest that small declines in scores on self-report attitude scales are related to a recalibration of trainees' understandings of patient-centredness as they grow more clinically experienced. The evolved construct of patient-centredness and the way attitudes are measured require special attention in the development of future instruments.

Diameter controlled synthesis of tungsten oxide nanorod bundles for highly sensitive NO2 gas sensors

Attempts to improve the performances and cost effectiveness of gas sensors for practical applications have led to the development of advanced nanostructured materials, which enabled the fabrication of highly sensitive and selective sensing devices. This study introduced the diameter controlled synthesis of scalable and large-quantity nanoporous tungsten oxide nanorod bundles for highly sensitive NO2 gas sensor applications. The diameter controlled nanoporous tungsten oxide nanorod bundles were synthesized by a facile hydrothermal method. The morphologies of the nanorod bundles were controlled by varying the amount of pluronic P123 surfactant. Gram quantities of the nanoporous tungsten oxide nanorod bundles were easily obtained and found effective in the fabrication of scalable gas sensors using a spray technique. Investigation on the gas sensing properties demonstrated that the nanoporous tungsten oxide nanorod bundles based gas sensor exhibited a relatively high response due to their small size (~20nm) and nanoporous structure, which provided large adsorption sites and accelerated the accession of the analytic gas molecules. The developed sensor enabled the monitoring of highly toxic NO2 gas at low concentrations among other contaminants. The response to 5ppm NO2 was 126-folds higher than that to 200ppm NH3. The sensor also exhibited outstanding stability when operated at 250°C. No distortion in sensor response was observed after five measurement cycles.

Does elastography reduce the need for thyroid FNAs?

Ultrasound elastography (USE) assesses lesion stiffness by evaluating tissue distortion in response to stress; it is emerging as a potentially useful tool to augment the ultrasound characterisation of thyroid nodules. The aim of this study was to assess the accuracy of USE examination of thyroid nodules compared with pathological outcome, especially to determine whether USE could reliably detect benign nodules and reduce the numbers of ultrasound guided fine needle aspiration cytology (USgFNAC). Over a three-year period, thyroid nodules were initially characterised by B-mode ultrasound (US) findings. Where USgFNAC was indicated by clinical concern and/or the sonographic appearances, the lesion was then subjected to USE by an experienced operator prior to the USgFNAC. 147 thyroid nodules were examined by USE and USgFNAC in 146 patients. The elastographic appearance was subjectively categorized at the time of the examination (soft, intermediate or hard) and subsequently compared with the cytological/histological outcome. A total of 122 nodules were non-neoplastic, 5 nodules were benign neoplasms, 10 nodules had indeterminate cytology and 10 were malignant neoplasms. The sensitivity of USE for malignancy was 90.0%, specificity was 79.6%, PPV was 24.3%, NPV was 99.1% and accuracy was 80.3%. Thyroid nodules that are soft at USE have a high likelihood of being non-neoplastic and subjective USE assessment of thyroid nodules by an experienced operator can be a useful means of avoiding USgFNAC for benign nodules. In contrast, we suggest that all nodules that are intermediate or hard on USE undergo USgFNAC.

An experimental-finite element analysis of the plane stress local torsion

The plane stress local torsion (PSLT) is an attractive method to strengthen the material in the areas of interest. A closed form solution of the problem is complex and an interpretation of the measured raw torque–twist data into the effective stress and strain is not straightforward. These hinder the optimization and control of the technique. In this study, the PSLT test was performed using Ti-IF steel specimens and their torque–twist response and radial distortion were compared with those obtained from an elastic–plastic model of the PSLT developed by the commercial finite element software, ABAQUS. The resultant microstructure in the samples as a result of large local shear strains and the extent of deformation were studied using SEM and a grid distortion technique, respectively. Mechanical property changes after the PSLT processing were characterized in samples of different geometry using a dedicated formulation based on the similarity theory. The micro shear punch tests allowed characterizing the gradient of the reinforcement in the radial direction of the samples.

HEARING AID WITH ENHANCED VENT

A hearing aid with a microphone for receiving acoustic signals and converting them to electrical signals, electronic circuitry for processing the electrical signals, and a speaker for converting the processed electrical signals into acoustic signals, has a shell that encases at least portions of the microphone, the electronic circuitry, and the speaker, the shell further encasing an inside volume. The hearing aid further has a vent that provides an opening between the inside volume and a region external to the hearing aid. A flexible membrane is provided that covers an opening of the vent and an acoustic resistor that contacts the flexible membrane. The membrane helps prevent wax fumes from entering the inside volume, and the acoustic resistor helps to reduce distortion in the frequency response of the hearing aid.

看護学生の対人関係場面における認知のゆがみのタイプとストレス反応との関連

目的：看護学生の対人関係場面における認知のゆがみのパターンとストレス反応との関係性について検討した．方法：看護学生307名を対象として，対人関係場面の認知のゆがみとストレス反応を調べるための調査を実施し，両者の関連性について分析した．結果：認知のゆがみ得点に基づくクラスター分析の結果，認知のゆがみのタイプは，ゆがみ低群，ゆがみ高群，仲間拒否群，謙遜群の4群に分類された．各群のストレス反応は，ゆがみ低群は他群と比較して低く，ゆがみ高群は他群と比較して高かった．また，仲間拒否群は，謙遜群と比較して情動的ストレス反応が高かった．結論：対人関係場面での認知のゆがみが全般的に強い学生や回避的な認知傾向がある学生では，心理的ストレス反応が高くなることが示唆された．この結果は，看護学生のストレスマネジメントにおいて，認知再構成法のような認知行動的な技法を取り入れることの重要性を示している．

Empirical Mode Decomposition Application for Structural Seismic Responses

Large mass method is used to calculate structural seismic responses of long-span bridges. Due to the inherent characteristics of large mass method, the larger scale of long span bridge, different geological conditions, seismic input time delay of different foot stall, the displacement curve of seismic responses will be drifted and distorted from the normal. In this paper, Empirical Mode Decomposition（EMD) based on the large mass method is proposed to remove pseudo component and drift displacement. Then displacement response curve is reconstructed using the remaining components, the drift and distortion of structural seismic responses is successfully removed by this method.

Social Desirability and Self-Reports: Testing a Content and Response-Style Model of Socially Desirable Responding

Personality assessment as a pre-employment screening procedure receives great interest from both researchers and practitioners. One key concern for selection specialists is represented by the response distortion among job applicants completing personality inventories. There are different operationalizations of socially desirable responding. One of the most accepted operationalizations was provided by Paulhus who distinguished between two social desirability factors (the egoistic and moralistic bias) as well as their conscious and unconscious aspects (management and enhancement). The aim of the study reported here is to test the basic assumption of the Paulhus model of socially desirable responding. A convenience sample of 200 students (N = 21.61; SD = 1.46) completed the Comprehensive Inventory of Desirable Responding (Paulhus, 2006) and the International Personality Item Pool Questionnaire (Goldberg, 1999; by Goldberg et al., 2006). Questionnaires were applied in three conditions: honest responding, responding as an ideal manager job applicant, and as an ideal teacher applicant. Results give partial support to the existence of egoistic and moralistic bias. However, conscious and unconscious aspects of distortion were not found. In conclusion it could be said that Paulhus’ model doesn’t provide a full answer to the problem of the nature of socially desirable responding.

Responding to Personality Tests in a Selection Context: The Role of the Ability to Identify Criteria and the Ideal-Employee Factor

Personality assessments are often distorted during personnel selection, resulting in a common “ideal-employee factor” (IEF) underlying ratings of theoretically unrelated constructs. However, this seems not to affect the personality measures' criterion-related validity. The current study attempts to explain this set of findings by combining the literature on response distortion with the ones on cognitive schemata and on candidates' ability to identify criteria (ATIC). During a simulated selection process, 149 participants filled out Big Five personality measures and participated in several high- and low-fidelity work simulations to estimate their managerial performance. Structural equation modeling showed that the IEF presents an indicator of response distortion and that ATIC accounted for variance between the IEF and performance during the work simulations, even after controlling for self-monitoring and general mental ability.

A potential inflating effect in estimation models: Cautionary evidence from comparing performance enhancing drug and herbal hormonal supplement use estimates

ObjectivesThis paper compares two indirect prevalence estimation methods that offer protection beyond anonymity and are suitable for self-administration, for investigating the epidemiology of transgressive or socially sensitive behaviours. DesignIn this self-report study, 513 participants (58.7% male) from sports clubs across the UK and southern Ireland were asked to complete an anonymous survey containing the recently developed Single Sample Count (SSC), along with a comparative method Unrelated Question Model (UQM), using prohibited performance-enhancing drugs/substances (PED) as sensitive and hormone-boosting herbal supplements (HS) as non-sensitive control questions. MethodThe survey comprised of sections of SSC, UQM, social projection and simple network scale up methods. Respondents were asked to indicate whether they preferred the SSC or UQM for more protection and ease of completion. ResultsA large discrepancy was observed in prevalence estimates for PED using the UQM (58.4%) and SSC (19.8%), but not for HS (54.9% and 54.0%, respectively). The SSC prevalence estimate for PED was in keeping with the results from social projection (13.8% in own sport; 26.1% in all sports) and network scale up (19.3% for known and suspected doping combined). A clear preference was logged for SSC. ConclusionSSC, but not UQM, showed good concurrent validity with social projection and personal networks for PED; and good discriminant validity with HS. The observed discrepancy could be explained by strategic responding which can inflate the proportion of ‘yes’ answers in the UQM. Adaptation of the UQM for self-administration may lead to an unwanted upward response distortion via strategic responding.

Globalised disease control and response distortion: a case study of avian influenza pandemic preparedness in Zambia

The past decade and a half has witnessed an increased and justified interest in global pandemic preparedness, owing to the unprecedented global spread of infectious disease threats, such as Severe Acute Respiratory Syndrome (SARS), H5N1 avian influenza and H1N1 Influenza. The repercussions of human and animal mortalities, and economic losses, have justified the need for globalised disease control responses through global pandemic preparedness. However, the blurring of the distinction between national and global preparedness has implications for the appropriateness of local disease control responses, particularly for poor resource countries reliant on donor aid to support their own preparedness. Examining the case of avian and pandemic preparedness in Zambia, this article explains how international funding led to a distortion of the pandemic response in this developing country. Despite the gains made under the global call for pandemic preparedness, the resulting avian and pandemic influenza response was inappropriate when weighed against Zambia's risk of an H5N1 incursion and the country's wider trade, agricultural and health priorities. We conclude that pandemic preparedness policy processes should take into consideration both the local policy context and realistic risk assessments of the local likelihood and potential impact of disease to ensure both the appropriateness and the sustainability of disease control measures instituted.

Fitting a Thurstonian IRT model to forced-choice data using Mplus

To counter response distortions associated with the use of rating scales (a.k.a. Likert scales), items can be presented in a comparative fashion, so that respondents are asked to rank the items within blocks (forced-choice format). However, classical scoring procedures for these forced-choice designs lead to ipsative data, which presents psychometric challenges that are well described in the literature. Recently, Brown and Maydeu-Olivares (Educational and Psychological Measurement 71: 460-502, 2011a) introduced a model based on Thurstone's law of comparative judgment, which overcomes the problems of ipsative data. Here, we provide a step-by-step tutorial for coding forced-choice responses, specifying a Thurstonian item response theory model that is appropriate for the design used, assessing the model's fit, and scoring individuals on psychological attributes. Estimation and scoring is performed using Mplus, and a very straightforward Excel macro is provided that writes full Mplus input files for any forced-choice design. Armed with these tools, using a forced-choice design is now as easy as using ratings.

Do Applicants Fake Their Personality Questionnaire Responses and How Successful are Their Attempts? A Case of Military Pilot Cadet Selection

This paper presents the results of three interrelated studies investigating the occurrence of response distortion on personality questionnaires within selection and the success of applicants in faking situations. In Study 1, comparison of the Big Five personality scores obtained from applicants in a military pilot cadet selection procedure with participants responding honestly, faking good, and faking an ideal candidate revealed that applicants responded more desirable than participants responding honestly but less desirable than respondents under fake instructions. The occurrence of faking within the military pilot selection process was replicated in Study 2 using the Eysenck Personality Questionnaire and another comparison group. Finally, in Study 3, comparison of personality profiles obtained in selection and ‘fake job’ situations with experts' estimates indicated that participants were partially successful in faking the desirable profile.

TELL ME SOME MORE: EXPLORING HOW VERBAL ABILITY AND ITEM VERIFIABILITY INFLUENCE RESPONSES TO BIODATA QUESTIONS IN A HIGH‐STAKES SELECTION CONTEXT

Although self‐rated or self‐scored selection measures are commonly used in selection contexts, they are potentially susceptible to applicant response distortion or faking. The response elaboration technique (RET), which requires job applicants to provide supporting information to justify their responses, has been identified as a potential way to minimize applicant response distortion. In a large‐scale, high‐stakes selection context (N= 16,304), we investigate the extent to which RET affects responding on a biodata test as well as the underlying reasons for any potential effect. We find that asking job applicants to elaborate their responses leads to overall lower scores on a biodata test. Item verifiability affects the extent to which RET decreases faking, which we suggest is due to increased accountability. In addition, verbal ability was more strongly related to biodata item scores when items require elaboration, although the effect of verbal ability was small. The implications of these findings for reducing faking in personnel selection are delineated.

The Development of Modulated, Quasi-Isothermal and Ultraslow Thermal Methods as a Means of Characterizing the α to γ Indomethacin Polymorphic Transformation

While polymorphism remains a key issue within the pharmaceutical and related industries, the understanding of the transformation process itself remains relatively poorly understood. In this study we use a combination of conventional and modulated temperature differential scanning calorimetry (MTDSC), quasi-isothermal MTDSC (Qi-MTDSC) and ultraslow heating rate MTDSC as a novel means of investigating the temperature-induced α to γ transformation in indomethacin, using hot stage microscopy and variable temperature attenuated total reflectance FTIR spectroscopy as supportive techniques. In particular, we utilize the ability of MTDSC to measure subtle heat capacity changes through the transformation, we examine the use of Lissajous analysis of the modulated heating signal itself (both scanning and quasi-isothermal) and finally we investigate the use of ultraslow heating rates (down to 0.04 °C/min) so as to facilitate examination of the melt-crystallization process at a scanning rate whereby kinetic hindrance becomes negligible. Indomethacin was prepared in the metastable α and stable γ forms using standard approaches. Samples were studied using conventional DSC, Qi-MTDSC (involving holding and modulating the sample at a series of incremental temperature steps) and ultraslow MTDSC. All studies were conducted using a Q-1000 MTDSC using crimped pans, following standard calibration procedures. Conventional DSC at 10 °C/min showed the expected single melting responses for the α and γ forms, while MTDSC at slower rates indicated the presence of a melt-crystallization process. Quasi-isothermal studies allowed the heat capacity to be estimated as a function of time, while the associated Lissajous analysis demonstrated distortion of the elliptical response as a result of the kinetic events involved. Ultraslow heating resulted in superimposition of the melting and crystallization processes, resulting in a discrete thermal event that was enthalpically equivalent to the difference between the two processes. It is suggested that these combined thermal methods allow the conversion to be profiled in a manner which facilitates both kinetic and thermodynamic analysis of the transformation.

Large signal response and harmonic distortion in piezoelectrics for SONAR transducers

Nonlinearity in the piezoelectric response limits the operating conditions of underwater transducers. In this work, the nonlinear effects are evaluated in terms of electrical current and induced strain as a function of drive level. Nonlinearity is further quantified within the active transduction material by evaluating the total harmonic distortion (THD) in the electromechanical response. Modified single crystals based on the binary lead magnesium niobate—lead titanate system were investigated. It is shown that single crystals show greater mechanical response and reduced THD, enabling operation at higher power levels. The performance of these single crystals is also compared to conventional high power lead zirconate titanate ceramics.

Optimal Higher Order Ambisonics Encoding With Predefined Constraints

In this paper, we propose a design method for 3-D higher order ambisonics (3-D HOA) encoding matrices which offers the possibility to impose spatial stop-bands in the directivity patterns of all the spherical-harmonic audio channels while keeping the transformed audio channels still compatible with the 3-D HOA reproduction sound format. This might be useful as an encoding technique which suppresses interfering signals from specific directions in a 3-D HOA recording, or in other situations where certain spatial areas should be suppressed. The design method is adapted from recent work on the optimization of spherical microphone array beamforming. Using the proposed optimization method and the spherical harmonics mathematics framework, the relationship between several design factors, e.g., distortions in the desired response, the dynamic range of matrix coefficients, can be analyzed and illustrated as function of frequency. Based on the proposed optimization formulation, additional constraints can also be easily included and solved. In some of the formulations, the processing can be applied as a matrix multiplication to recorded spherical harmonics coefficients, that is, already encoded 3-D HOA format signals. The modified signals can be of the same or a lower spherical harmonics order. For a full optimization that gives a globally optimal solution, on the other hand, the processing must be applied to the microphone signals themselves. Numerical and experimental results validate the proposed method.