7,340 research outputs found
Compositional Verification for Autonomous Systems with Deep Learning Components
As autonomy becomes prevalent in many applications, ranging from
recommendation systems to fully autonomous vehicles, there is an increased need
to provide safety guarantees for such systems. The problem is difficult, as
these are large, complex systems which operate in uncertain environments,
requiring data-driven machine-learning components. However, learning techniques
such as Deep Neural Networks, widely used today, are inherently unpredictable
and lack the theoretical foundations to provide strong assurance guarantees. We
present a compositional approach for the scalable, formal verification of
autonomous systems that contain Deep Neural Network components. The approach
uses assume-guarantee reasoning whereby {\em contracts}, encoding the
input-output behavior of individual components, allow the designer to model and
incorporate the behavior of the learning-enabled components working
side-by-side with the other components. We illustrate the approach on an
example taken from the autonomous vehicles domain
LANDSAT range resource information system project, volume 1
There are no author-identified significant results in this report
TurKit: Tools for iterative tasks on mechanical Turk
Mechanical Turk (MTurk) is an increasingly popular web service for paying people small rewards to do human computation tasks. Current uses of MTurk typically post independent parallel tasks. We are exploring an alternative iterative paradigm, in which workers build on or evaluate each other's work. We describe TurKit, a new toolkit for deploying iterative tasks to MTurk, with a familiar imperative programming paradigm that effectively uses MTurk workers as subroutines.National Science Foundation (U.S.). (Grant number IIS-0447800)Quanta Computer (Firm)Massachusetts Institute of Technology. Center for Collective Intelligenc
Damage identification in a concrete beam using curvature difference ratio
Previous studies utilising changes in mode shape or curvature to locate damage rely on the fact that the greatest change occurs around the defect. However, in concrete beams this fact is undermined due to the nature of the defect as distributed multi-site cracks. In addition, differences in mode shape and curvature as ways to locate the damage is unstable because of occurrence of modal nodes and inflection points. In this paper, one interesting solution to this problem is being tested by establishing a new non-dimensional expression designated the 'Curvature Difference Ratio (CDR)'. This parameter exploits the ratio of differences in curvature of a specific mode shape for a damaged stage and another reference stage. The expression CDR is reasonably used to locate the damage and estimate the dynamic bending stiffness in a successively loaded 6m concrete beam. Results obtained by the proposed technique are tested and validated with a case study results done by Ren and De Roeck [1] also by Maeck and De Roeck [2]. Another contribution of this work is that relating changes in vibration properties to the design bending moment at beam sections as defined in Eurocode 2 specifications [3]. Linking between a beam section condition and the change in vibration data will help to give a better comprehension on the beam condition than the applied load
The role of metaphor in shaping the identity and agenda of the United Nations: the imagining of an international community and international threat
This article examines the representation of the United Nations in speeches delivered by its Secretary General. It focuses on the role of metaphor in constructing a common ‘imagining’ of international diplomacy and legitimising an international organisational identity. The SG legitimises the organisation, in part, through the delegitimisation of agents/actions/events constructed as threatening to the international community and to the well-being of mankind. It is a desire to combat the forces of menace or evil which are argued to motivate and determine the organisational agenda. This is predicated upon an international ideology of humanity in which difference is silenced and ‘working towards the common good’ is emphasised. This is exploited to rouse emotions and legitimise institutional power. Polarisation and antithesis are achieved through the employment of metaphors designed to enhance positive and negative evaluations. The article further points to the constitutive, persuasive and edifying power of topic and situationally-motivated metaphors in speech-making
Efficient computation of matched solutions of the Kapchinskij-Vladimirskij envelope equations for periodic focusing lattices
A new iterative method is developed to numerically calculate the periodic,
matched beam envelope solution of the coupled Kapchinskij-Vladimirskij (KV)
equations describing the transverse evolution of a beam in a periodic, linear
focusing lattice of arbitrary complexity. Implementation of the method is
straightforward. It is highly convergent and can be applied to all usual
parameterizations of the matched envelope solutions. The method is applicable
to all classes of linear focusing lattices without skew couplings, and also
applies to all physically achievable system parameters -- including where the
matched beam envelope is strongly unstable. Example applications are presented
for periodic solenoidal and quadrupole focusing lattices. Convergence
properties are summarized over a wide range of system parameters.Comment: 20 pages, 5 figures, Mathematica source code provide
Space capsule Patent
Manned space capsule configuration for orbital flight and atmospheric reentr
Pamela: development of the RF system for a non-relativistic non-scaling FFAG
The PAMELA project(Particle Accelerator For MEdical
Applications) currently consists of the design of a particle
therapy facility. The project, which is in the design phase,
contains Non-Scaling FFAG, particle accelerator capable
of rapid beam acceleration, giving a pulse repetition rate of
1kHz, far beyond that of a conventional synchrotron. To
realise the repetition rate, a key component of the accelerator
is the rf accelerating system. The combination of a high
energy gain per turn and a high repetition rate is a significant
challenge. In this paper, options for the rf system of
the proton ring and the status of development are presented
Implementing health promotion programmes in schools: a realist systematic review of research and experience in the United Kingdom
Background: Schools have long been viewed as a good setting in which to encourage healthy lifestyles amongst children, and schools in many countries aspire to more comprehensive, integrated approaches to health promotion. Recent reviews have identified evidence of the effects of school health promotion on children’s and young people’s health. However, understanding of how such programmes can be implemented in schools is more limited.
Methods: We conducted a realist review to identify the conditions and actions which lead to the successful implementation of health promotion programmes in schools. We used the international literature to develop programme theories which were then tested using evaluations of school health promotion programmes conducted in the United Kingdom (UK). Iterative searching and screening was conducted to identify sources and clear criteria applied for appraisal of included sources. A review advisory group comprising educational and public health practitioners, commissioners, and academics was established at the outset.
Results: In consultation with the review advisory group, we developed four programme theories (preparing for implementation, initial implementation, embedding into routine practice, adaptation and evolution); these were then refined using the UK evaluations in the review. This enabled us to identify transferable mechanisms and enabling and constraining contexts and investigate how the operation of mechanisms differed in different contexts. We also identified steps that should be taken at a senior level in relation to preparing for implementation (which revolved around negotiation about programme delivery) and initial implementation (which centred on facilitation, support, and reciprocity—the latter for both programme deliverers and pupils). However, the depth and rigour of evidence concerning embedding into routine practice and adaptation and evolution was limited.
Conclusions: Our findings provide guidance for the design, implementation, and evaluation of health promotion in schools and identify the areas where further research is needed
Task search in a human computation market
In order to understand how a labor market for human computation functions, it is important to know how workers search for tasks. This paper uses two complementary methods to gain insight into how workers search for tasks on Mechanical Turk. First, we perform a high frequency scrape of 36 pages of search results and analyze it by looking at the rate of disappearance of tasks across key ways Mechanical Turk allows workers to sort tasks. Second, we present the results of a survey in which we paid workers for self-reported information about how they search for tasks. Our main findings are that on a large scale, workers sort by which tasks are most recently posted and which have the largest number of tasks available. Furthermore, we find that workers look mostly at the first page of the most recently posted tasks and the first two pages of the tasks with the most available instances but in both categories the position on the result page is unimportant to workers. We observe that at least some employers try to manipulate the position of their task in the search results to exploit the tendency to search for recently posted tasks. On an individual level, we observed workers searching by almost all the possible categories and looking more than 10 pages deep. For a task we posted to Mechanical Turk, we confirmed that a favorable position in the search results do matter: our task with favorable positioning was completed 30 times faster and for less money than when its position was unfavorable.National Science Foundation (U.S.). Integrative Graduate Education and Research Traineeship (Multidisciplinary Program in Inequality & Social Policy) (Grant Number 033340
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