Lattice structures for bisimilar Probabilistic Automata

The paper shows that there is a deep structure on certain sets of bisimilar Probabilistic Automata (PA). The key prerequisite for these structures is a notion of compactness of PA. It is shown that compact bisimilar PA form lattices. These results are then used in order to establish normal forms not only for finite automata, but also for infinite automata, as long as they are compact.Comment: In Proceedings INFINITY 2013, arXiv:1402.661

Towards faster numerical solution of Continuous Time Markov Chains stored by symbolic data structures

This work considers different aspects of model-based performance- and dependability analysis. This research area analyses systems (e.g. computer-, telecommunication- or production-systems) in order to quantify their performance and reliability. Such an analysis can be carried out already in the planning phase, without a physically existing system. All aspects treated in this work are based on finite state spaces (i.e. the models only have finitely many states) and a representation of the state graphs by Multi-Terminal Binary Decision Diagrams (MTBDDs). Currently, there are many tools that transform high-level model specifications (e.g. process algebra or Petri-Net) to low-level models (e.g. Markov chains). Markov chains can be represented by sparse matrices. For complex models very large state spaces may occur (this phenomenon is called state space explosion in the literature) and accordingly very large matrices representing the state graphs. The problem of building the model from the specification and storing the state graph can be regarded as solved: There are heuristics for compactly storing the state graph by MTBDD or Kronecker data structure and there are efficient algorithms for the model generation and functional analysis. For the quantitative analysis there are still problems due to the size of the underlying state space. This work provides some methods to alleviate the problems in case of MTBDD-based storage of the state graph. It is threefold: 1. For the generation of smaller state graphs in the model generation phase (which usually are easier to solve) a symbolic elimination algorithm is developed. 2. For the calculation of steady-state probabilities of Markov chains a multilevel algorithm is developed which allows for faster solutions. 3. For calculating the most probable paths in a state graph, the mean time to the first failure of a system and related measures, a path-based solver is developed

„…und dann fiel ich aus allen Wolken – das war tiefste Pionierarbeit“ : betriebsfamiliale Systeme am Beispiel der Hausmutter-Funktion – methodisch angelehnt an den Ansatz der Grounded Theory

Da bislang keine empirischen Ergebnisse zur Funktion der Hausmutter vorliegen, soll mit einer qualitativen Untersuchung, die dem Stil der Grounded Theory folgt, herausgefunden werden, wie sich die Hausmutter-Funktion in der zweiten Hälfte des 20. Jahrhunderts in der Interaktion mit Bewohnern gestaltete und welche Bedeutung ihr zugeschrieben wurde. Es konnten insgesamt neun Hausmütter und acht Hausväter für ein Oral-History-Interview (n = 17) gewonnen werden. Anhand der Ergebnisse konnten drei Phasen der Hausmutter-Funktion definiert werden, von denen im vorliegenden Bericht die zweite Phase: „Sich als Hausmutter verwirklichen – umgesetzte Macht und Herrschaft“ fokussiert wird. Die Ergebnisse zeigen, dass Hausmüttern mit der Kernkategorie: „Macht und Herrschaft“ ein großes Potential oblag, Entscheidungen für die im Haus Lebenden zu treffen, was sich anhand von Machtformen und Stabilisierungsformen der Macht veranschaulichen lässt. Vielfach haben sich Hausmütter eingesetzt, Bedingungen für eine bessere Pflege zu verändern. Die Ergebnisse der Studie können helfen, gemeinschaftliches Leben zu reflektieren, da die Phänomene „Macht und Herrschaft“ in der pflegerischen Versorgung bis heute an Aktualität nicht verloren haben. Empirical results concerning the function of house-mothers do not exist. This qualitative study was designed to establish the nature and importance of interactions between house-mothers and occupants for the second half of the 20th century. A sample of nine house-mothers and eight house-fathers were recruited with whom it was possible to conduct oral history interviews (n=17). Analysis of the data revealed three functional phases of their work, with this paper dealing with the second, “Fulfilling one’s potential as a house-mother – implementation of power and dominance”. Results in the main category of power and dominance showed them having a high incidence of decision making for the house residents, an illustration of the power/stabilisation model of power House-mothers reported the need for changes in care provisions to improve the quality of services, a reflection on their own functional activity. This finding is relevant because it would appear that the phenomena of power and dominance has not lost its significance for communal living, even in the 21st century

«Mein Lohn ist, dass ich darf» : wie Hausmütter den Machtverlust ihrer Position in Häusern für «Kranke und Pflegebedürftige» zwischen 1945 und 1995 im Rückblick erinnerten

Betriebsfamilien waren im 20. Jahrhundert weit verbreitet. Da kaum empirisches Material zur Funktion der Hausmutter existiert, sollte in einer qualitativen Studie untersucht werden, wie Mitglieder die Funktion der Hausmutter zwischen 1945 und 1995 erinnerten und wie gemeinschaftliches Leben in damaligen Betriebsfamilien möglich war. Methodisch orientierte sich das Vorgehen sowohl an dem Verfahren der Oral History und an den Ansätzen der Grounded Theory als auch an der sequenziellen Line-by-Line-Analysis. Betriebsfamilien waren im 20. Jahrhundert weit verbreitet. Da kaum empirisches Material zur Funktion der Hausmutter existiert, sollte in einer qualitativen Studie untersucht werden, wie Mitglieder die Funktion der Hausmutter zwischen 1945 und 1995 erinnerten und wie gemeinschaftliches Leben in damaligen Betriebsfamilien möglich war. Methodisch orientierte sich das Vorgehen sowohl an dem Verfahren der Oral History und an den Ansätzen der Grounded Theory als auch an der sequenziellen Line-by-Line-Analysis. Aus den Befragungen der Gesamtstudie (n = 42) wurden für den vorliegenden Artikel die Interviews mit neun Hausmüttern verwendet. Fokussiert wurde die Frage, wie Hausmütter berufsbezogene Entwicklungen im Rückblick erlebten und wie diese auf die Funktion der Hausmutter Einfluss genommen haben. Als Ergebnis konnten drei Phasen definiert werden, welche die Hausmutter mit ihrer Funktion durchlief. Dieser Artikel beschreibt die dritte Phase «Aus der Funktion der Hausmutter ausscheiden – verlorene und enttäuschte Macht und Herrschaft». Hausmütter waren nicht nur Hauswirtschafterinnen, sondern auch Pflegende, die mit ihrer Stellung im Haus neben dem Hausvater das betriebsfamiliale Oberhaupt bildeten. Mit den Mitgliedern der «Familie» in einem Haus zu leben belastete Hausmütter, gleichzeitig konnten sie aber davon profitieren, weil sie über viele Freiheiten verfügten, was mit der Kernkategorie Macht und Herrschaft beschrieben werden konnte. Institutional families were widespread in the 20th century. As there is very little empirical material on the function of the housemother, a qualitative study was launched to explore members' memories of the function of the housemother between 1945 and 1995 and how communal life in the institutional families of the period was possible. The study was methodologically oriented towards oral history techniques and the principles of Grounded Theory as well as towards sequential line by line analysis. For the purposes of this article, the interviews with nine housemothers were selected from the interviews conducted for the wider study (n = 42). The central question concerned how housemothers experienced professional developments in retrospect and the influence these had on the function of the housemother. The interviews resulted in the definition of three phases which the housemothers passed through during their role as housemother. This article describes the third phase: “Leaving the function of the housemother – lost and frustrated power and dominance”. Housemothers were not only housekeepers but also carers. Together with their husbands, they represented the heads of their institutional families. Housemothers found living in one house with the other members of the “family” a burden, but at the same time they benefitted from the great freedom they had. This aspect is described using the core categories of power and dominance

Women’s memories of themselves on their journeys to housemother-style roles, 1945–1995

Diakonische Betriebsfamilien stellten im 20. Jahrhundert in Deutschland eine bedeutende Ressource im Hinblick auf die langfristige Betreuung von Kranken und behinderten Menschen dar. Da kaum empirisches Material zur Funktion der Hausmutter existierte, wurde untersucht, wie sich die Hausmutter-Funktion in der zweiten Hälfte des 20. Jahrhunderts in der Interaktion mit den Mitgliedern der Familie gestaltete und welche Bedeutung ihr zugeschrieben wurde. Für den vorliegenden Artikel wurden die Interviews von neun Hausmüttern verwendet. Orientiert an den Prinzipien der Grounded Theory nach Strauss und Corbin konnten im Gesamtergebnis drei Phasen beschrieben werden, welche die Hausmutter während ihrer Funktion durchlief. Mit der Kernkategorie Macht und Herrschaft stellt der vorliegende Artikel die erste Phase der Hausmutter-Funktion dar und zeigt, dass der Weg zur Hausmutter mit vielen Entbehrungen und einer Überforderung verbunden war. Hausmütter absolvierten zwar einen „Brautkurs“, jedoch fühlten sie sich besonders zu Beginn ihrer Funktion häufig überfordert und nur wenig auf die Funktion als Hausmutter vorbereitet. Die Erkenntnisse über die drei Phasen der Hausmutter-Funktion können zum gegenseitigen Verständnis von Pflegenden beitragen und verdeutlichen, dass professionelle Pflege am Beispiel von Betriebsfamilien gewachsen ist. In the twentieth century, diaconical institutional families represented a significant resource in the long-term care of sick and disabled people in Germany. As little empirical material on life in institutional families existed, a qualitative study was carried out to explore aspects of the role of the housemother in the context of their interactions with residents in the second half of the twentieth century and to find out it is importance was attached to this role. For this article nine former housemothers were interviewed using oral history interviews. The qualitative study based on grounded theory approach, following Strauss & Corbin. The phenomena of power and domination form the central category, which can then be divided into three phases of the role of the housemother. This article exclusively concentrates on the first phase: “‘Setting out as a bride’ – borrowed power and domination”. The process of becoming a housemother was accompanied by a great deal of sacrifice. Today, the role of the housemother is seen as outdated as it was based strongly on structures of power and domination. Understanding the three phases of the housemother role can contribute towards a mutual understanding of care providers and show that professional nursing care has grown out of the example of institutional families

Efficacy of motor imagery in post-stroke rehabilitation: a systematic review

BACKGROUND: Evaluation of how Motor Imagery and conventional therapy (physiotherapy or occupational therapy) compare to conventional therapy only in their effects on clinically relevant outcomes during rehabilitation of persons with stroke. DESIGN: Systematic review of the literature METHODS: We conducted an electronic database search in seven databases in August 2005 and also hand-searched the bibliographies of studies that we selected for the review.Two reviewers independently screened and selected all randomized controlled trials that compare the effects of conventional therapy plus Motor Imagery to those of only conventional therapy on stroke patients.The outcome measurements were: Fugl-Meyer Stroke Assessment upper extremity score (66 points) and Action Research Arm Test upper extremity score (57 points).Due to the high variability in the outcomes, we could not pool the data statistically. RESULTS: We identified four randomized controlled trials from Asia and North America. The quality of the included studies was poor to moderate. Two different Motor imagery techniques were used (three studies used audiotapes and one study had occupational therapists apply the intervention). Two studies found significant effects of Motor Imagery in the Fugl-Meyer Stroke Assessment: Differences between groups amounted to 11.0 (1.0 to 21.0) and 3.2 (-4 to 10.3) respectively and in the Action Research Arm Test 6.1 (-6.2 to 18.4) and 15.8 (0.5 to 31.0) respectively. One study did not find a significant effect in the Fugl-Meyer Stroke Assessment and Color trail Test (p = 0.28) but in the task-related outcomes (p > 0.001). CONCLUSION: Current evidence suggests that Motor imagery provides additional benefits to conventional physiotherapy or occupational therapy. However, larger and methodologically sounder studies should be conducted to assess the benefits of Motor imagery

Retinal Vascular Occlusion after COVID-19 Vaccination : More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study

Background: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). Methods: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June–31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case– control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. Results: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case–control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60–1.45, p = 0.75) in connection with a vaccination within a 4-week window. Conclusions: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk