617 research outputs found

    A Component-oriented Framework for Autonomous Agents

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    The design of a complex system warrants a compositional methodology, i.e., composing simple components to obtain a larger system that exhibits their collective behavior in a meaningful way. We propose an automaton-based paradigm for compositional design of such systems where an action is accompanied by one or more preferences. At run-time, these preferences provide a natural fallback mechanism for the component, while at design-time they can be used to reason about the behavior of the component in an uncertain physical world. Using structures that tell us how to compose preferences and actions, we can compose formal representations of individual components or agents to obtain a representation of the composed system. We extend Linear Temporal Logic with two unary connectives that reflect the compositional structure of the actions, and show how it can be used to diagnose undesired behavior by tracing the falsification of a specification back to one or more culpable components

    Is severity of motor coordination difficulties related to co-morbidity in children at risk for developmental coordination disorder?

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    Aim of the study was to investigate whether 7-9 year old children with severe motor difficulties are more at risk of additional difficulties in activities in daily living, academic skills, attention and social skills than children with moderate motor difficulties. Children (N=6959) from a population based cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC), were divided into three groups based on their scores on the ALSPAC Coordination Test at age 7: control children (scores above 15th centile; N=5719 [82.1%]); children with moderate (between 5th and 15th centile; N=951 [13.7%]); and children with severe motor difficulties (below 5th centile N=289 [4.2%]). Children with neurological disorders or an IQ<70 were excluded. Logistic regression was used to compare children with moderate and severe motor coordination difficulties with each other and with control children regarding their risk of co-morbidity defined as significant (<10th centile) difficulties with activities of daily living (ADL); academic skills (reading, spelling and handwriting); attention; social skills (social cognition and nonverbal skills). Children with severe motor difficulties demonstrated a higher risk of difficulties in ADL, handwriting, attention, reading, and social cognition than children with moderate motor difficulties, who in turn had a higher risk of difficulties than control children in five out of seven domains. Screening and intervention of co-morbid problems is recommended for children with both moderate and severe motor difficulties

    Conceptual process design of extractive distillation processes for ethylbenzene/styrene separation

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    In the current styrene production process the distillation of the close-boiling ethylbenzene/styrene mixture to obtain an ethylbenzene impurity level of 100 ppm in styrene accounts for 75–80% of the energy requirements. The future target is to reach a level of 1–10 ppm, which will increase the energy requirements for the distillation even further. Extractive distillation is a well-known technology to separate close-boiling mixtures up to high purities. The objective of this study was to investigate whether extractive distillation using ionic liquids (ILs) is a promising alternative to obtain high purity styrene. Three ILs were studied: [3-mebupy][B(CN)4], [4-mebupy][BF4], and [EMIM][SCN]. Extractive distillation with sulfolane and the current conventional distillation process were used as benchmark processes. The IL [4-mebupy][BF4] is expected to outperform the other two ILs with up to 11.5% lower energy requirements. The operational expenditures of the [4-mebupy][BF4] process are found to be 43.2% lower than the current distillation process and 5% lower than extractive distillation with sulfolane extractive distillations. However, the capital expenditures for the sulfolane process will be about 23% lower than those for the [4-mebupy][BF4] process. Finally, the conclusion can be drawn from the total annual costs that all studied extractive distillation processes outperform the current distillation process to obtain high purity styrene, but that the ILs evaluated will not perform better than sulfolan

    Венчурні інвестиції: сутність, форми, контрагенти

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    У статті досліджено генезис категорії "венчурні інвестиції", еволюцію форм організації венчурних інвестицій, конкретизовано специфіку інвесторів і реципієнтів венчурного капіталу

    The AIMS home-video method: parental experiences and appraisal for use in neonatal follow-up clinics

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    BACKGROUND: In The Netherlands, prematurely born infants and their parents are offered regular developmental check-ups in a hospital setting. In line with providing healthcare at distance, the use of video footage showing the infant's behavior and movements, taken by parents at home and assessed by professionals online, might be a fruitful future practice. The focus of this study was to gain insight into parental experiences with the Alberta Infant Motor Scale home-video method and their appraisal of its applicability for use in an outpatient neonatal follow-up clinic. METHOD: A qualitative descriptive study among parents of healthy extremely or very premature infants (GA 26.2-31.5 weeks) participating in a longitudinal study of motor development between 3-18 months corrected age. Ten semi-structured interviews were conducted and transcribed verbatim. Data was analyzed independently. Inductive content analysis was performed following the process of the AIMS home-video method. RESULTS: Parents appraised the AIMS home-video method as manageable and fun to do. Instructions, instruction film, and checklists were clear. Transferring the video footage from their phone to their computer and uploading it to the web portal was sometimes time-consuming. Parents gained a better awareness of their infant's motor development and found the provided feedback a confirmation of what they already thought about their infant's development and was reassuring that their child was doing well. First-time parents seemed more uncertain and had a greater need for information about (motor) development, but on the other hand, also had confidence in their child. All parents thought that home-videos can be an addition to follow-up visits, but cannot replace (all) visits. It may be an opportunity to reduce the frequency of hospital visits, while still having their infant monitored. CONCLUSION: Parents appraised the AIMS home-video method positively and are of the opinion that home-videos can be of added value in monitoring infants at risk in neonatal follow-up additional to hospital visits. In future research a user-friendly application and/or platform to exchange video footage safely between parents and professionals should be developed with all possible stakeholders involved and implementation should be explored

    Service orchestration with priority constraints

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    Business process management is an operational management approach that focuses on improving business processes. Business processes, i.e., collections of important activities in an organization, are represented in the form of a workflow, an orchestrated and repeatable pattern of activities amenable to automated analysis and control. Priority is an important concept in modeling workflows. We need priority to model cancelable and compensable tasks within transactional business processes. We use the Reo coordination language to model and formally analyze workflows. In this paper, we propose a constraint-based approach to formalize priority in Reo. We introduce special channels to propagate and block priority flows, define their semantics as constraints, and model priority propagation as a constraint satisfaction problem

    A Reo model of Software Defined Networks

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    Reo is a compositional coordination language for component connectors with a formal semantics based on automata. In this paper, we propose a formal model of software defined networks (SDNs) based on Reo where declarative constructs comprising of basic Reo primitives compose to specify descriptive models of both data and control planes of SDNs. We first describe the model of an SDN switch which can be compactly represented as a single state constraint automaton with a memory storing its flow table. A full network can then be compositionally constructed by composing the switches with basic communication channels. The reactive and proactive behaviour of the controllers in the control plane of an SDN can also be modelled by Reo connectors, which can compose the connectors representing data plane. The resulting model is suitable for testing, simulation, visualization, verification, and ultimately compilation into SDN switch code using the standard tools already available for Reo

    Algebraic service composition for user-centric IoT applications

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    The Internet of Things (IoT) requires a shift in our way of building applications, as it is aimed at providing many services to society in general. Non-developer people require increasingly complex IoT applications and support for their ever changing run-time requirements. Although service composition allows the combination of functionality into more complex behaviours, current approaches provide support for dealing with one IoT scenario at a time, as they allow the definition of only one workflow. In this paper, we present DX-MAN, an algebraic model for static service composition that allows the definition of composite services that encompass multiple workflows for run-time scenarios. We evaluate our proposal on an example in the domain of smart homes
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