title: The Use of Language Projection for Compositional Verification of Discrete Event Systems

authors: Ware, Simon

subjects: computer science

abstract: This paper proposes the use of abstraction by language projection to improve the performance of compositional verification to prove or disprove that a large system of composed finite-state machines satisfies a given safety property. Algorithms are presented for the automatic verification of language inclusion and controllability for discrete event systems, and are applied to a set realistic industrial examples. The experimental results suggest that the method can improve performance considerably, particularly in cases where previous methods of compositional verification fail because a large number of automata need to be considered.

text: The Use of Language Projection for Compositional Verification of Discrete Event Systems This paper proposes the use of abstraction by language projection to improve the performance of compositional verification to prove or disprove that a large system of composed finite-state machines satisfies a given safety property. Algorithms are presented for the automatic verification of language inclusion and controllability for discrete event systems, and are applied to a set realistic industrial examples. The experimental results suggest that the method can improve performance considerably, particularly in cases where previous methods of compositional verification fail because a large number of automata need to be considered.

year: 2008

title: Validating the depression anxiety stress scales (DASS-21) across Germany, Ghana, India, and New Zealand using Rasch methodology

authors: Adu, P

subjects: Anxiety

abstract: Psychological distress is widespread globally, affects both mental and physical health, and has been significantly exacerbated by the COVID-19 pandemic. Reliable and valid instruments to assess psychological distress are needed so that interventions to address this condition can be directed and evaluated. We evaluated the psychometric statistics of the Depression Anxiety Stress Scales (DASS-21) using the Rasch method and a population survey sample dataset from four nations. To meet the requirements of the Rasch model, we randomly selected 500 participants (at least 110 from each country) from a total sample of 1822 individuals from Germany (n = 475), Ghana (n = 523), India (n = 411), and New Zealand (n = 413). Minor testlet modifications were necessary to achieve a satisfactory model fit for the depression (χ2 (30) = 40.32, p = 0.099), anxiety (χ2 (32) = 31.22, p = 0.510), and stress (χ2 (20) = 29.64, p = 0.076) subscales, and the full-scale (χ2 (18) = 23.93, p = 0.16). The scales were strictly unidimensional with acceptable reliability reflected by Person Separation Index (PSI) values of 0.86 for depression, 0.74 for anxiety, 0.82 for stress, and 0.87 for the total scale. The scales’ items showed invariance across the countries and sociodemographic factors. The scales also demonstrated convergent, structural, and external validities. The study supported the reliability and validity of the DASS-21 for assessing psychological distress in four countries. Rasch model algorithms developed in this study enable conversion of the ordinal DASS-21 scale and its subscale scores to interval-level scores, which increases the precision of measurement. Future studies should apply Rasch methodology to the DASS-21 in various cultural contexts, incorporating subgroup analyses.

text: Validating the depression anxiety stress scales (DASS-21) across Germany, Ghana, India, and New Zealand using Rasch methodology Psychological distress is widespread globally, affects both mental and physical health, and has been significantly exacerbated by the COVID-19 pandemic. Reliable and valid instruments to assess psychological distress are needed so that interventions to address this condition can be directed and evaluated. We evaluated the psychometric statistics of the Depression Anxiety Stress Scales (DASS-21) using the Rasch method and a population survey sample dataset from four nations. To meet the requirements of the Rasch model, we randomly selected 500 participants (at least 110 from each country) from a total sample of 1822 individuals from Germany (n = 475), Ghana (n = 523), India (n = 411), and New Zealand (n = 413). Minor testlet modifications were necessary to achieve a satisfactory model fit for the depression (χ2 (30) = 40.32, p = 0.099), anxiety (χ2 (32) = 31.22, p = 0.510), and stress (χ2 (20) = 29.64, p = 0.076) subscales, and the full-scale (χ2 (18) = 23.93, p = 0.16). The scales were strictly unidimensional with acceptable reliability reflected by Person Separation Index (PSI) values of 0.86 for depression, 0.74 for anxiety, 0.82 for stress, and 0.87 for the total scale. The scales’ items showed invariance across the countries and sociodemographic factors. The scales also demonstrated convergent, structural, and external validities. The study supported the reliability and validity of the DASS-21 for assessing psychological distress in four countries. Rasch model algorithms developed in this study enable conversion of the ordinal DASS-21 scale and its subscale scores to interval-level scores, which increases the precision of measurement. Future studies should apply Rasch methodology to the DASS-21 in various cultural contexts, incorporating subgroup analyses.

year: 2025

title: The TOHU framework: Sensing and interpreting tohu to heal from trauma

authors: McLachlan, A

subjects: Environment

abstract: This hypotheses article presents understandings and practices of tohu (signs) in the personal, eco-environmental, and spiritual wellbeing of Māori. Tohu can be observed in the natural, social, physical, or spiritual environment, and within a Māori worldview provide important ways of understanding and responding to phenomena. Wānanga (shared dialogue and debate) were held with seven Māori clinical psychologists from He Paiaka Tōtara (Māori Psychologist Network) and two mātauranga Māori specialists to explore their experiences, knowledge, and perspectives about tohu, with their insights collected through online information sharing. Our wānanga goals were to inform the creation of a therapeutic framework to address patu ngākau, psychological and spiritual trauma experienced by Māori. The results identified that tohu are located within the person and their environment, and the importance of exploring how tohu are interpreted. We propose a TOHU acronym as a framework for understanding and addressing the multifaceted impacts of patu ngākau.

text: The TOHU framework: Sensing and interpreting tohu to heal from trauma This hypotheses article presents understandings and practices of tohu (signs) in the personal, eco-environmental, and spiritual wellbeing of Māori. Tohu can be observed in the natural, social, physical, or spiritual environment, and within a Māori worldview provide important ways of understanding and responding to phenomena. Wānanga (shared dialogue and debate) were held with seven Māori clinical psychologists from He Paiaka Tōtara (Māori Psychologist Network) and two mātauranga Māori specialists to explore their experiences, knowledge, and perspectives about tohu, with their insights collected through online information sharing. Our wānanga goals were to inform the creation of a therapeutic framework to address patu ngākau, psychological and spiritual trauma experienced by Māori. The results identified that tohu are located within the person and their environment, and the importance of exploring how tohu are interpreted. We propose a TOHU acronym as a framework for understanding and addressing the multifaceted impacts of patu ngākau.

year: 2024