From patterned response dependency to structured covariate dependency: categorical-pattern-matching

Data generated from a system of interest typically consists of measurements from an ensemble of subjects across multiple response and covariate features, and is naturally represented by one response-matrix against one covariate-matrix. Likely each of these two matrices simultaneously embraces heterogeneous data types: continuous, discrete and categorical. Here a matrix is used as a practical platform to ideally keep hidden dependency among/between subjects and features intact on its lattice. Response and covariate dependency is individually computed and expressed through mutliscale blocks via a newly developed computing paradigm named Data Mechanics. We propose a categorical pattern matching approach to establish causal linkages in a form of information flows from patterned response dependency to structured covariate dependency. The strength of an information flow is evaluated by applying the combinatorial information theory. This unified platform for system knowledge discovery is illustrated through five data sets. In each illustrative case, an information flow is demonstrated as an organization of discovered knowledge loci via emergent visible and readable heterogeneity. This unified approach fundamentally resolves many long standing issues, including statistical modeling, multiple response, renormalization and feature selections, in data analysis, but without involving man-made structures and distribution assumptions. The results reported here enhance the idea that linking patterns of response dependency to structures of covariate dependency is the true philosophical foundation underlying data-driven computing and learning in sciences.Comment: 32 pages, 10 figures, 3 box picture

Construct Validity of the Swedish Version of the Revised Piper Fatigue Scale in an Oncology Sample—A Rasch Analysis

AbstractObjectivesFatigue is a common and distressing symptom in cancer patients due to both the disease and its treatments. The concept of fatigue is multidimensional and includes both physical and mental components. The 22-item Revised Piper Fatigue Scale (RPFS) is a multidimensional instrument developed to assess cancer-related fatigue. This study reports on the construct validity of the Swedish version of the RPFS from the perspective of Rasch measurement.MethodsThe Swedish version of the RPFS was answered by 196 cancer patients fatigued after 4 to 5 weeks of curative radiation therapy. Data from the scale were fitted to the Rasch measurement model. This involved testing a series of assumptions, including the stochastic ordering of items, local response dependency, and unidimensionality. A series of fit statistics were computed, differential item functioning (DIF) was tested, and local response dependency was accommodated through testlets.ResultsThe Behavioral, Affective and Sensory domains all satisfied the Rasch model expectations. No DIF was observed, and all domains were found to be unidimensional. The Mood/Cognitive scale failed to fit the model, and substantial multidimensionality was found. Splitting the scale between Mood and Cognitive items resolved fit to the Rasch model, and new domains were unidimensional without DIF.ConclusionsThe current Rasch analyses add to the evidence of measurement properties of the scale and show that the RPFS has good psychometric properties and works well to measure fatigue. The original four-factor structure, however, was not supported

How predictable are spontaneous decisions and hidden intentions? Comparing classification results based on previous responses with multivariate pattern analysis of fMRI BOLD signals

In two replication studies we examined response bias and dependencies in voluntary decisions. We trained a linear classifier to predict “spontaneous decisions” and in the second study “hidden intentions” from responses in preceding trials and achieved comparable prediction accuracies as reported for multivariate pattern classification based on voxel activities in frontopolar cortex. We discuss implications of our findings and suggest ways to improve classification analyses of fMRI BOLD signals that may help to reduce effects of response dependencies between trials

Michael Smith and the daleks: reason, morality, and contingency

Smith has defended the rationalist's conceptual claim that moral requirements are categorical requirements of reason, arguing that no status short of this would make sense of our taking these requirements as seriously as we do. Against this I argue that Smith has failed to show either that our moral commitments would be undermined by possessing only an internal, contextual justification or that they need presuppose any expectation that rational agents must converge on their acceptance. His claim that this rationalistic understanding of metaethics is required for the intelligibility of moral disagreement is also found to be inadequately supported. It is further proposed that the rationalist's substantive claims - that there are such categorical requirements of reason and that our actual moral commitments are a case in point - are liable to disappointment; and that the conceptual claim is fatally undermined by reflection on how we might best respond to such disappointment

Optical power model of a laser bar diode

This article proposes a modelling method for laser diodes optical output power including its dependency on temperature. The device used for this study is a 40 W Monocrom's diode, with 808 nm wavelength emitted light and with a 19 emitters CS mount laser bar, mounted using the patented Monocrom's clamping method. The aim of this study is to propose a Pspice modelling of the laser diode device, mainly focusing in the optical output power variation with the temperature and allowing its computer simulation. Also to setup a characterization system to obtain the necessary parameters values for the optical model mathematical expressions. Therefore, the article explains the proposed method for the optical output power model generation of the laser bar diode and how its parameters values are obtained, an optical output power measurement setup and its calibration, the obtained Pspice model and its simulation, and the characterization system that allows to obtain the necessary parameters with short rise up time current slopes. Finally, evaluation of results and related conclusions are exposed.Peer ReviewedPostprint (author's final draft

Sub-diffraction thin-film sensing with planar terahertz metamaterials

Planar metamaterials have been recently proposed for thin dielectric film sensing in the terahertz frequency range. Although the thickness of the dielectric film can be very small compared with the wavelength, the required area of sensed material is still determined by the diffraction-limited spot size of the terahertz beam excitation. In this article, terahertz near-field sensing is utilized to reduce the spot size. By positioning the metamaterial sensing platform close to the sub-diffraction terahertz source, the number of excited resonators, and hence minimal film area, are significantly reduced. As an additional advantage, a reduction in the number of excited resonators decreases the inter-cell coupling strength, and consequently the resonance Q factor is remarkably increased. The experimental results show that the resonance Q factor is improved by 113%. Moreover, for a film with a thickness of \lambda/375 the minimal area can be as small as 0.2\lambda by 0.2\lambda. The success of this work provides a platform for future metamaterial-based sensors for biomolecular detection.Comment: 8 pages, 6 figure

Using the Rasch measurement theory to assess the psychometric properties of the Hopkins Symptom Checklist-10 in adolescents

Background The Hopkins Symptom Checklist-10 (HSCL-10) is widely used to measure psychological distress in adolescents. To provide valid and reliable results and generate recommendations for practice and policies, instruments with sound psychometric properties are required. The purpose of this study is to use Rasch measurement theory to assess the psychometric properties of the HSCL-10 among adolescents aged 13–19. Methods In this cross-sectional study, 6445 adolescents responded to a web-based questionnaire. Data were collected from lower and upper secondary schools in Norway during 2018. The data were analysed using the partial credit parameterisation of the unidimensional Rasch model. Results HSCL-10 was found to be unidimensional and to have acceptable reliability. One pair of items showed response dependency. The targeting of the instrument could have been better. All items had ordered thresholds. Three items under-discriminated and three displayed differential item functioning regarding gender. Conclusions HSCL-10 has potential for measuring psychological distress in adolescents, though there is room for improvement. To further improve this instrument, some items should be rephrased.publishedVersio