Derivation of logic programs

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Transforming specifications of observable behaviour into programs

A methodology for deriving programs from specifications of observable behaviour is described. The class of processes to which this methodology is applicable includes those whose state changes are fully definable by labelled transition systems, for example communicating processes without internal state changes. A logic program representation of such labelled transition systems is proposed, interpreters based on path searching techniques are defined, and the use of partial evaluation techniques to derive the executable programs is described

Selection of Ordinally Scaled Independent Variables

Ordinal categorial variables are a common case in regression modeling. Although the case of ordinal response variables has been well investigated, less work has been done concerning ordinal predictors. This article deals with the selection of ordinally scaled independent variables in the classical linear model, where the ordinal structure is taken into account by use of a difference penalty on adjacent dummy coefficients. It is shown how the Group Lasso can be used for the selection of ordinal predictors, and an alternative blockwise Boosting procedure is proposed. Emphasis is placed on the application of the presented methods to the (Comprehensive) ICF Core Set for chronic widespread pain. The paper is a preprint of an article accepted for publication in the Journal of the Royal Statistical Society Series C (Applied Statistics). Please use the journal version for citation

Implementation of quasi-static time series simulations for analysis of the impact of electric vehicles on the grid

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In this paper, symmetrical electric vehicle charging impacts in existing low-voltage distribution grid are investigated throughout proposed methodology and their results analysed. Symmetrical loading- and voltage-related impacts are assessed for the extensive grid. A synthetic EV mix pattern was used with the purpose to demonstrate a universal observation of charging impacts. These patterns were allocated quasi-randomly to the points of common coupling within the grid based on predefined scenarios - 8, 10, 12 and 20 percent. Subsequently, quasi-static time series simulations for a duration of one year in 10-minute time steps were executed. Consequently, this paper yields results, which offer practical insight in the maximum share of electric vehicle charging in low-voltage distribution grids and provide guidance for future decision-making of distribution grid operators

Designing effective policies for minimal agents

A policy for a minimal reactive agent is a set of condition-action rules used to determine its response to perceived environmental stimuli. When the policy pre-disposes the agent to achieving a stipulated goal we call it a teleo-reactive policy. This paper presents a framework for constructing and evaluating teleo-reactive policies for one or more minimal agents, based upon discounted-reward evaluation of policy-restricted subgraphs of complete situation-graphs. The main feature of the method is that it exploits explicit and definite associations of the agent’s perceptions with states. The combinatorial burden that would potentially ensue from such associations can be ameliorated by suitable use of abstractions. The framework allows one to plan for a number of agents by focusing upon the behaviour of a single representative of them. It allows for varied behaviour to be modelled, including communication between agents. Simulation results presented here indicate that the method affords a good degree of scalability and predictive power

Optimizing minimal agents through abstraction

Abstraction is a valuable tool for dealing with scalability in large state space contexts. This paper addresses the design, using abstraction, of good policies for minimal autonomous agents applied within a situation-graph-framework. In this framework an agent’s policy is some function that maps perceptual inputs to actions deterministically. A good policy disposes the agent towards achieving one or more designated goal situations, and the design process aims to identify such policies. The agents to which the framework applies are assumed to have only partial observability, and in particular may not be able to perceive fully a goal situation. A further assumption is that the environment may influence an agent’s situation by unpredictable exogenous events, so that a policy cannot take advantage, of a reliable history of previous actions. The Bellman discount measure provides a means of evaluating situations and hence the overall value of a policy. When abstraction is used, the accuracy of the method can be significantly improved by modifying the standard Bellman equations. This paper describes the modification and demonstrates its power through comparison with simulation results

Wizard building in an abstract portal framework

This report investigates a particular way in which enterprise portals can support the working life of their users. Through monitoring a user's behaviour and observing archetypal sequences of actions, the system constructs abstract templates of tools that assist him to carry out such sequences efficiently and easily in the future. We call these new tools "wizards" after the utilities introduced by Microsoft into their applications and operating systems, designed to guide users through potentially complex tasks such as constructing graphs in Excel or setting up the computer to access the Internet. At the heart of the process lies a re-programmable rule-base that encodes the principles by which action records are to be assembled into intelligible generic patterns of working practice, and thence converted into templates of new wizard tools that provide direct support for those patterns

Auswirkungen der in der Geburtshilfe verwendeten Medikamente Betamethason, Indometacin und Fenoterol auf den Aktivierungszustand von neonatalen und maternalen Monozyten

Escherichia coli (E. coli) ist der zweithäufigste Erreger, der für neonatale Frühsepsis (engl. early-onset sepsis) verantwortlich ist. Bei Frühgeborenen, mit einem geringen Geburtsgewicht (engl. very-low-birth-weight infants) ist E. coli sogar hauptverantwortlich für eine Frühsepsis. Zudem ist die Mortalität bei einer Frühsepsis, ausgelöst durch E. coli, am höchsten. Bei infektionsbedingter drohender Frühgeburt werden in der Geburtshilfe Glukokortikoide zur Lungenreifung und Tokolytika zur Wehenhemmung eingesetzt. Monozyten spielen eine zentrale und essenzielle Rolle bei der Bekämpfung von Infektionen. Sie bekämpfen Mikroben direkt über die Produktion von reaktiven Sauerstoffspezies und Phagozytose. Monozyten aktivieren zudem T-Zellen über Antigenpräsentation und steuern die Immunantwort durch die Ausschüttung verschiedener Zytokine. In dieser Studie wurden die Einflüsse von Betamethason, Indometacin und Fenoterol auf den Aktivierungszustand und die Zytokinausschüttung von maternalen und neonatalen Monozyten während einer Infektion untersucht. Mononukleäre Zellen wurden mittels Dichtegradientenzentrifugation aus Nabelschnurblut (neonatal) und dem peripheren Blut der korrespondierenden Mutter (maternal) isoliert. Die Zellen wurden anschließend in vitro mit E. coli Lysat stimuliert und mit Betamethason, Indometacin und Fenoterol inkubiert. Nach einer 24-stündigen Inkubation wurde die Oberflächenexpression von Aktivierungsmarkern der Monozyten mittels Durchflusszytometrie untersucht. Die Ausschüttung von Zytokinen wurde mittels ELISA gemessen. Die Ergebnisse zeigen, dass die in vitro Behandlung neonataler und maternaler Zellen kurz nach Spontangeburt mit Betamethason allein oder in Kombination mit einem der beiden Tokolytika zu einem verringerten Aktivierungszustand der Monozyten führt. Diese Hemmung der Aktivierung zeigt sich nicht nur phänotypisch, sondern ist auch der Grund für die verminderte Ausschüttung proinflammatorischer Zytokine. Da diese Zytokine die Immunantwort maßgeblich aktivieren und steuern, ist davon auszugehen, dass Betamethason die Immunantwort beeinträchtigt. Da das neonatale Immunsystem unreif und naiv ist und daher diverse Beeinträchtigungen aufweist, sind Neonaten generell anfälliger für Infektionen. Durch die Gabe von Betamethason wird die Aktivierung und Funktion der Monozyten gehemmt und das beeinträchtigte neonatale Immunsystem möglicherweise zusätzlich geschwächt. Fenoterol und Indometacin scheinen die immunsuppressive Wirkung von Betamethason zusätzlich zu verstärken. Die Indikation und der Zeitpunkt einer pränatalen Betamethason- und Tokolytikagabe sollte also in jedem Fall sorgfältig geprüft werden

A study of aspects of the biology and distribution of freshwater crayfish in the Thames catchment

The results presented in this thesis concern an examination of the biology and distribution of freshwater crayfish in the Thames Catchment. Studies of the distribution of both the native (Austropotamobius pallipes. Lereb.), and an introduced (Pace as acus leniusculus. Dana.) species have been undertaken and attempts to evaluate some of the factors controlling distribution have been made. The specific influences of river engineering works on populations of A. pallipes have been studied in more detail. Data concerning A. pallipes at the population level has been obtained by sampling a single lacustrine population. A comparison has been made with crayfish from a riverine population. Information concerning life-history, growth, density and trophic position is discussed and is related to similar information from elsewhere in the Thames Catchment and the U.K. The morphology of A. alli es in this area has been quantified and an assessment made of sexually dimorphic features and hence the size at maturity of A. pallipes in southern England. The collection of information regarding diseases and parasites of A. pallipes in the Thames Catchment has been undertaken throughout the study and the incidence and importance of these is discussed. Comparable information has been obtained from a population of the introduced P. leniusculus. Survival of implants, growth and life-history of this alien species in a single population are discussed in detail and compared with information collected from other introduced populations in the Thames Catchment. The morphometry of P. leniusculus has been investigated and their size at maturity calculated. The data collected concerning P. leniusculus forms the only known study of this species in -the U. K., to date, and the results are compared with information from Scandinavia and North America. The results from both parts of this thesis are discussed in terms of the ecological and economic importance of crayfish populations and the effects that introductions of alien species may have on native populations. It is intended that this thesis should provide a full and accurate assessment of the status of freshwater crayfish in the Thames Catchment at a time when increasing pressures may result in serious alterations to stocks of both species