919 research outputs found

    An Architecture for Provenance Systems

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    This document covers the logical and process architectures of provenance systems. The logical architecture identifies key roles and their interactions, whereas the process architecture discusses distribution and security. A fundamental aspect of our presentation is its technology-independent nature, which makes it reusable: the principles that are exposed in this document may be applied to different technologies

    Bringing social reality to multiagent and service architectures : practical reductions for monitoring of deontic-logic and constitutive norms

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    As distributed systems grow in complexity, the interactions among individuals (agents, services) of such systems become increasingly more complex and therefore more difficult to constrain and monitor. We propose to view such systems as socio-technical systems, in which organisational and institutional concepts, such as norms, can be applied to improve not only control on the components but also their autonomy by the definition of soft rather than hard constraints. Norms can be described as rules that guide the behavior of individual agents pertaining to groups that abide to them, either by explicit or implicit support. The study of norms, and regulatory systems in general, in their many forms -e.g. social norms, conventions, laws, regulations- has been of interest since the beginning of philosophy, but has seen a lot of evolution during the 20th century due to the progress in the philosophy of language, especially concerning speech acts and deontic logic. Although there is a myriad of definitions and related terminologies about the concept of norm, and as such there are many perspectives on how to analyse their impact, a common denominator is that norms constrain the behaviour of groups of agents in a way that each individual agent can build, with a fair degree of confidence, expectations on how each of their counterparts will behave in the situations that the norms are meant to cover. For example, on a road each driver expects everybody else to drive on only one side of the road (right or left, depending on the country). Therefore, normative contexts, usually wrapped in the form of institutions, are effective mechanisms to ensure the stability of a complex system such as an organisation, a society, or even of electronic systems. The latter has been an object of interest in the field of Artificial Intelligence, and it has been seen as a paradigm of coordination among electronic agents either in multi-agent systems or in service-oriented architectures. In order to apply norms to electronic systems, research has come up with abstractions of normative systems. In some cases these abstractions are based on regimented systems with flexible definitions of the notion of norm, in order to include meanings of the concept with a coarse-grained level of logic formality such as conventions. Other approaches, on the other hand, propose the use of deontic logic for describing, from a more theoretical perspective, norm-governed interaction environments. In both cases, the purpose is to enable the monitoring and enforcement of norms on systems that include -although not limited to- electronic agents. In the present dissertation we will focus on the latter type, focusing on preserving the deontic aspect of norms. Monitoring in norm-governed systems requires making agents aware of: 1) what their normative context is, i.e. which obligations, permissions and prohibitions are applicable to each of them and how they are updated and triggered; and 2) what their current normative status is, i.e. which norms are active, and in what instances they are being fullfilled or violated, in order words, what their social -institutional- reality is. The current challenge is on designing systems that allow computational components to infer both the normative context and social reality in real-time, based on a theoretical formalism that makes such inferences sound and correct from a philosophical perspective. In the scope of multi-agent systems, many are the approaches proposed and implemented that full these requirements up to this date. However, the literature is still lacking a proposal that is suited to the current state-of-the-art in service-oriented architectures, more focused nowadays on automatically scalable, polyglot amalgams of lightweight services with extremely simple communication and coordination mechanisms- a trend that is being called “microservices”. This dissertation tackles this issue, by 1) studying what properties we can infer from distributed systems that allow us to treat them as part of a socio-technical system, and 2) analysing which mechanisms we can provide to distributed systems so that they can properly act as socio-technical systems. The main product of the thesis is therefore a collection of computational elements required for formally grounded and real-time e¬fficient understanding and monitoring of normative contexts, more specially: 1. An ontology of events to properly model the inputs from the external world and convert them into brute facts or institutional events; 2. A lightweight language for norms, suitable for its use in distributed systems; 3. An especially tailored formalism for the detection of social reality, based on and reducible to deontic logic with support for constitutive norms; 4. A reduction of such formalism to production rule systems; and 5. One or more implementations of this reduction, proven to e¬fficiently work on several scenarios. This document presents the related work, the rationale and the design/implementation of each one of these elements. By combining them, we are able to present novel, relevant work that enables the application of normative reasoning mechanisms in realworld systems in the form of a practical reasoner. Of special relevance is the fact that the work presented in this dissertation simplifies, while preserving formal soundness, theoretically complex forms of reasoning. Nonetheless, the use of production systems as the implementation-level materialisation of normative monitoring allows our work to be applied in any language and/or platform available, either in the form of rule engines, ECA rules or even if-then-else patterns. The work presented has been tested and successfully used in a wide range of domains and actual applications. The thesis also describes how our mechanisms have been applied to practical use cases based on their integration into distributed eldercare management and to commercial games.Con el incremento en la complejidad de los sistemas distribuidos, las interacciones entre los individuos (agentes, servicios) de dichos sistemas se vuelven más y más complejas y, por ello, más difíciles de restringir y monitorizar. Proponemos ver a estos sistemas como sistemas socio-técnicos, en los que conceptos organizacionales e institucionales (como las normas) pueden aplicarse para mejorar no solo el control sobre los componentes sino también su autonomía mediante la definición de restricciones débiles (en vez de fuertes). Las Normas se pueden describir como reglas que guían el comportamiento de agentes individuales que pertenecen a grupos que las siguen, ya sea con un apoyo explícito o implícito. El estudio de las normas y de los sistemas regulatorios en general y en sus formas diversas -normas sociales, convenciones, leyes, reglamentos- ha sido de interés para los eruditos desde los inicios de la filosofía, pero ha sufrido una evolución mayor durante el siglo 20 debido a los avances en filosofía del lenguaje, en especial los relacionados con los actos del habla -speech acts en inglés- y formas deónticas de la lógica modal. Aunque hay una gran variedad de definiciones y terminología asociadas al concepto de norma, y por ello existen varios puntos de vista sobre como analizar su impacto, el denominador común es que las normas restringen el comportamiento de grupos de agentes de forma que cada agente individual puede construir, con un buen nivel de confianza, expectativas sobre cómo cada uno de los otros actores se comportará en las situaciones que las normas han de cubrir. Por ejemplo, en una carretera cada conductor espera que los demás conduzcan solo en un lado de la carretera (derecha o izquierda, dependiendo del país). Por lo tanto, los contextos normativos, normalmente envueltos en la forma de instituciones, constituyen mecanismos efectivos para asegurar la estabilidad de un sistema complejo como una organización, una sociedad o incluso un sistema electrónico. Lo último ha sido objeto de estudio en el campo de la Inteligencia Artificial, y se ha visto como paradigma de coordinación entre agentes electrónicos, tanto en sistemas multiagentes como en arquitecturas orientadas a servicios. Para aplicar normas en sistemas electrónicos, los investigadores han creado abstracciones de sistemas normativos. En algunos casos estas abstracciones se basan en sistemas regimentados con definiciones flexibles del concepto de norma para poder influir algunos significados del concepto con un menor nivel de granularidad formal como es el caso de las convenciones. Otras aproximaciones proponen el uso de lógica deóntica para describir, desde un punto de vista más teórico, entornos de interacción gobernados por normas. En ambos casos el propósito es el permitir la monitorización y la aplicación de las normas en sistemas que incluyen -aunque no están limitados a- agentes electrónicos. En el presente documento nos centraremos en el segundo tipo, teniendo cuidado en mantener el aspecto deóntico de las normas. La monitorización en sistemas gobernados por normas requiere el hacer a los agentes conscientes de: 1) cual es su contexto normativo, es decir, que obligaciones permisos y prohibiciones se aplican a cada uno de ellos y cómo se actualizan y activan; y 2) cual es su estado normativo actual, esto es, que normas están activas, y que instancias están siendo cumplidas o violadas, en definitiva, cual es su realidad social -o institucional-. En la actualidad el reto consiste en diseñar sistemas que permiten inferir a componentes computacionales tanto el contexto normativo como la realidad social en tiempo real, basándose en un formalismo teórico que haga que dichas inferencias sean correctas y bien fundamentadas desde el punto de vista filosófico. En el ámbito de los sistemas multiagente existen muchas aproximaciones propuestas e implementadas que cubren estos requisitos. Sin embargo, esta literatura aun carece de una propuesta que sea adecuada para la tecnología de las arquitecturas orientadas a servicios, que están más centradas en amalgamas políglotas y escalables de servicios ligeros con mecanismos de coordinación y comunicación extremadamente simples, una tendencia moderna que lleva el nombre de microservicios. Esta tesis aborda esta problemática 1) estudiando que propiedades podemos inferir de los sistemas distribuidos que nos permitan tratarlos como parte de un sistema sociotécnico, y 2) analizando que mecanismos podemos proporcionar a los sistemas distribuidos de forma que puedan actuar de forma correcta como sistemas socio-técnicos. El producto principal de la tesis es, por tanto, una colección de elementos computacionales requeridos para la monitorización e interpretación e_cientes en tiempo real y con clara base formal. En concreto: 1. Una ontología de eventos para modelar adecuadamente las entradas del mundo exterior y convertirlas en hechos básicos o en eventos institucionales; 2. Un lenguaje de normas ligero y sencillo, adecuado para su uso en arquitecturas orientadas a servicios; 3. Un formalismo especialmente adaptado para la detección de la realidad social, basado en y reducible a lógica deóntica con soporte para normas constitutivas; 4. Una reducción de ese formalismo a sistemas de reglas de producción; y 5. Una o más implementaciones de esta reducción, de las que se ha probado que funcionan eficientemente en distintos escenarios. Este documento presenta el estado del arte relacionado, la justificación y el diseño/implementación para cada uno de esos elementos. Al combinarlos, somos capaces de presentar trabajo novedoso y relevante que permite la aplicación de mecanismos de razonamiento normativo en sistemas del mundo real bajo la forma de un razonador práctico. De especial relevancia es el hecho de que el trabajo presentado en este documento simplifica formas complejas y teóricas de razonamiento preservando la correctitud formal. El uso de sistemas de reglas de producción como la materialización a nivel de implementación del monitoreo normativo permite que nuestro trabajo se pueda aplicar a cualquier lenguaje o plataforma disponible, ya sea en la forma de motores de reglas, reglas ECA o incluso patrones si-entonces. El trabajo presentado ha sido probado y usado con éxito en un amplio rango de dominios y aplicaciones prácticas. La tesis describe como nuestros mecanismos se han aplicado a casos prácticos de uso basados en su integración en la gestión distribuida de pacientes de edad avanzada o en el sector de los videojuegos comerciales.Postprint (published version

    Architecture for Provenance Systems

    No full text
    This document covers the logical and process architectures of provenance systems. The logical architecture identifies key roles and their interactions, whereas the process architecture discusses distribution and security. A fundamental aspect of our presentation is its technology-independent nature, which makes it reusable: the principles that are exposed in this document may be applied to different technologies

    Public views on the donation and use of human biological samples in biomedical research: a mixed methods study

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    Objective A mixed methods study exploring the UK general public's willingness to donate human biosamples (HBSs) for biomedical research.<p></p> Setting Cross-sectional focus groups followed by an online survey.<p></p> Participants Twelve focus groups (81 participants) selectively sampled to reflect a range of demographic groups; 1110 survey responders recruited through a stratified sampling method with quotas set on sex, age, geographical location, socioeconomic group and ethnicity.<p></p> Main outcome measures (1) Identify participants’ willingness to donate HBSs for biomedical research, (2) explore acceptability towards donating different types of HBSs in various settings and (3) explore preferences regarding use and access to HBSs.<p></p> Results 87% of survey participants thought donation of HBSs was important and 75% wanted to be asked to donate in general. Responders who self-reported having some or good knowledge of the medical research process were significantly more likely to want to donate (p<0.001). Reasons why focus group participants saw donation as important included: it was a good way of reciprocating for the medical treatment received; it was an important way of developing drugs and treatments; residual tissue would otherwise go to waste and they or their family members might benefit. The most controversial types of HBSs to donate included: brain post mortem (29% would donate), eyes post mortem (35%), embryos (44%), spare eggs (48%) and sperm (58%). Regarding the use of samples, there were concerns over animal research (34%), research conducted outside the UK (35%), and research conducted by pharmaceutical companies (56%), although education and discussion were found to alleviate such concerns.<p></p> Conclusions There is a high level of public support and willingness to donate HBSs for biomedical research. Underlying concerns exist regarding the use of certain types of HBSs and conditions under which they are used. Improved education and more controlled forms of consent for sensitive samples may mitigate such concerns.<p></p&gt

    Consent for the use of human biological samples for biomedical research: a mixed methods study exploring the UK public’s preferences

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    OBJECTIVE: A mixed-methods study exploring the UK general public's views towards consent for the use of biosamples for biomedical research.<p></p> SETTING: Cross-sectional population-based focus groups followed by an online survey.<p></p> PARTICIPANTS: 12 focus groups (81 participants) selectively sampled to reflect a range of demographic groups; 1110 survey responders recruited through a stratified sampling method with quotas set on sex, age, geographical location, socioeconomic group and ethnicity.<p></p> MAIN OUTCOME MEASURES: (1) Views on the importance of consent when donating residual biosamples for medical research; (2) preferences for opt-in or opt-out consent approaches and (3) preferences for different consent models.<p></p> RESULTS: Participants believed obtaining consent for use of residual biosamples was important as it was 'morally correct' to ask, and enabled people to make an active choice and retain control over their biosamples. Survey responders preferred opt-in consent (55%); the strongest predictor was being from a low socioeconomic group (OR 2.22, 95% CI 1.41 to 3.57, p=0.001) and having a religious affiliation (OR 1.36, 95% CI 1.01 to 1.81, p=0.04). Focus group participants had a slight preference for opt-out consent because by using this approach more biosamples would be available and facilitate research. Concerning preferred models of consent for research use of biosamples, survey responders preferred specific consent with recontact for each study for which their biosamples are eligible. Focus group participants preferred generic consent as it provided 'flexibility for researchers' and reduced the likelihood that biosamples would be wasted. The strongest predictor for preferring specific consent was preferring opt-in consent (OR 4.58, 95% CI 3.30 to 6.35, p=0.015) followed by non-'White' ethnicity (OR 2.94, 95% CI 1.23 to 7.14, p<0.001).<p></p> CONCLUSIONS: There is a preference among the UK public for ongoing choice and control over donated biosamples; however, increased knowledge and opportunity for discussion is associated with acceptance of less restrictive consent models for some people.<p></p&gt

    USING BLOCKCHAIN TO SUPPORT PROVENANCE IN THE INTERNET OF THINGS

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    The Internet of Things (IoT) has gained traction in all sectors and pervades all spheres of our lives. With statistics projecting an increase in the number of devices by 87% as well as increase in security concerns, traceability within this IoT will become a major problem. As more devices communicate with each other via the Internet, it will be crucial to determine the origins of requests and responses. Being able to store records related to the life cycle of requests and responses in an immutable form will provide documentary evidence that will help to establish transparency and accountability within the IoT. Previous works employed provenance techniques to address this problem but focuses on the request perspective. However, little or nothing has been done regarding the response perspective. Consequently, this thesis proposes and develops a blockchain-based provenance system to trace bi-directionally the sources of requests and responses in the IoT. This is achieved through the investigation of historical communication records. Furthermore, a performance evaluation of the system is provided. The results show that the developed system is scalable under real-world setting

    A population genetic study of Pasqueflower: In situ and Ex situ Conservation Genetics of a Vulnerable UK Plant Species

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    The population genetic structure of the vulnerable UK plant species Anemone pulsatilla L. reflects geographic patterns of historical range fragmentation and the influence of population decline and restoration intervention. Positive spatial auto-correlation of natural in situ populations of A. pulsatilla lends support to a scenario for genetic drift (i.e. random drift of allelic frequencies) driving the emergence of population genetic structure as a consequence of fragmentation. Multivariate and STRUCTURE analysis estimates the partitioning of genetic variation among four natural population genetic clusters (broadly defined by geographical regions of the species’ range) and a fifth, highly differentiated, genetic cluster defined by introduced genotypes of unverifiable genetic origin to the casually augmented AN population. It is recommended that restoration intervention (i.e. to augment declining populations or introduce populations to enhance gene flow) source propagules for introduction from within the local population genetic cluster in order to maximise the potential for introduction/exchange of locally adaptive genetic variation. The existing ex situ gene conservation strategy for A. pulsatilla can be predicted to under-represent the species’ natural genetic variability due to limited sampling effort. At a minimum, a representative ex situ gene conservation strategy for the safeguard of A. pulsatilla UK variability should aim to capture representative accessions from the most diverse population/s of each of the four natural population genetic clusters. It is also recommended that the six native AN genotypes are sampled for ex situ conservation due to a disproportionately high level of unique genetic variation. A pilot study of regenerated ex situ accessions supports a prediction that the following factors act on genetic diversity: (a) survivorship; (b) number of generation removed from the wild; (c) effective population size
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