211,193 research outputs found
The DSA Toolkit Shines Light Into Dark and Stormy Archives
Web archive collections are created with a particular purpose in mind. A curator selects seeds, or original resources, which are then captured by an archiving system and stored as archived web pages, or mementos. The systems that build web archive collections are often configured to revisit the same original resource multiple times. This is incredibly useful for understanding an unfolding news story or the evolution of an organization. Unfortunately, over time, some of these original resources can go off-topic and no longer suit the purpose for which the collection was originally created. They can go off-topic due to web site redesigns, changes in domain ownership, financial issues, hacking, technical problems, or because their content has moved on from the original topic. Even though they are off-topic, the archiving system will still capture them, thus it becomes imperative to anyone performing research on these collections to identify these off-topic mementos. Hence, we present the Off-Topic Memento Toolkit, which allows users to detect off-topic mementos within web archive collections. The mementos identified by this toolkit can then be separately removed from a collection or merely excluded from downstream analysis. The following similarity measures are available: byte count, word count, cosine similarity, Jaccard distance, Sørensen-Dice distance, Simhash using raw text content, Simhash using term frequency, and Latent Semantic Indexing via the gensim library. We document the implementation of each of these similarity measures. We possess a gold standard dataset generated by manual analysis, which contains both off-topic and on-topic mementos. Using this gold standard dataset, we establish a default threshold corresponding to the best F1 score for each measure. We also provide an overview of potential future directions that the toolkit may take
PADAMOT : project overview report
Background and relevance to radioactive waste management
International consensus confirms that placing radioactive wastes and spent nuclear fuel deep
underground in a geological repository is the generally preferred option for their long-term
management and disposal. This strategy provides a number of advantages compared to leaving it
on or near the Earth’s surface. These advantages come about because, for a well chosen site, the
geosphere can provide:
• a physical barrier that can negate or buffer against the effects of surface dominated natural
disruptive processes such as deep weathering, glaciation, river and marine erosion or
flooding, asteroid/comet impact and earthquake shaking etc.
• long and slow groundwater return pathways from the facility to the biosphere along which
retardation, dilution and dispersion processes may operate to reduce radionuclide
concentration in the groundwater.
• a stable, and benign geochemical environment to maximise the longevity of the engineered
barriers such as the waste containers and backfill in the facility.
• a natural radiation shield around the wastes.
• a mechanically stable environment in which the facility can be constructed and will
afterwards be protected.
• an environment which reduces the likelihood of the repository being disturbed by inadvertent
human intrusion such as land use changes, construction projects, drilling, quarrying and
mining etc.
• protection against the effects of deliberate human activities such as vandalism, terrorism and
war etc.
However, safety considerations for storing and disposing of long-lived radioactive wastes must
take into account various scenarios that might affect the ability of the geosphere to provide the
functionality listed above. Therefore, in order to provide confidence in the ability of a repository
to perform within the deep geological setting at a particular site, a demonstration of geosphere
“stability” needs to be made. Stability is defined here to be the capacity of a geological and
hydrogeological system to minimise the impact of external influences on the repository
environment, or at least to account for them in a manner that would allow their impacts to be
evaluated and accounted for in any safety assessments.
A repository should be sited where the deep geosphere is a stable host in which the engineered
containment can continue to perform according to design and in which the surrounding
hydrogeological, geomechanical and geochemical environment will continue to operate as a
natural barrier to radionuclide movement towards the biosphere. However, over the long periods
of time during which long-lived radioactive wastes will pose a hazard, environmental change at
the surface has the potential to disrupt the stability of the geosphere and therefore the causes of
environmental change and their potential consequences need to be evaluated.
As noted above, environmental change can include processes such as deep weathering,
glaciation, river and marine erosion. It can also lead to changes in groundwater boundary
conditions through alternating recharge/discharge relationships. One of the key drivers for
environmental change is climate variability. The question then arises, how can geosphere stability be assessed with respect to changes in climate? Key issues raised in connection with
this are:
• What evidence is there that 'going underground' eliminates the extreme conditions that
storage on the surface would be subjected to in the long term?
• How can the additional stability and safety of the deep geosphere be demonstrated with
evidence from the natural system?
As a corollary to this, the capacity of repository sites deep underground in stable rock masses to
mitigate potential impacts of future climate change on groundwater conditions therefore needs to
be tested and demonstrated. To date, generic scenarios for groundwater evolution relating to
climate change are currently weakly constrained by data and process understanding. Hence, the
possibility of site-specific changes of groundwater conditions in the future can only be assessed
and demonstrated by studying groundwater evolution in the past. Stability of groundwater
conditions in the past is an indication of future stability, though both the climatic and geological
contexts must be taken into account in making such an assertion
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Freeing up access to learning: the role for Open Educational Resources
The internet revolution of the last few years has had an impact on how we all live our lives. So it is not surprising that this is also a time of change in attitudes towards how we learn. Free access to information through computer networks has expanded, and part of that information flow are materials designed to help people learn. In addition there are many further online resources that help the learning process, even if that was not the original aim. However, there are risks in this evolution in access to information both for the end user, who can be confused by the options available to them, and to those involved in providing education, who may see their traditional role changing and becoming harder to perform. This situation provides the background for a growing movement to directly consider how education can be provided in a freer and more open way. This has been termed “Open Educational Resources” (OER). The exact definition of the term depends on interpretation, however a useful statement was provided as an outcome from an event organized by UNESCO in 2002 as:
“OER are teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use or re-purposing by others. Open educational resources include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge (Atkins, Brown and Hammond, 2007, p4).”
Arguably the only difference between an online learning object and an open educational resource is the declaration that it is open. This may be true but that turns out to be a powerful difference. By being open the content can be accessed by any learner who can do so, it can be taken and run in new contexts, it can be reworked by others and adapted for local needs (with the result shared back if desired), it can be made part of shared pool of resources, it can be the shared point of reference for collaboration, and it can be the key to building policies that work in different domain
The Alternative Library
Much time and effort has been devoted to designing and developing library Web sites that are easy to navigate by both new students and experienced researchers. In a review of the Southampton Institute Library it was decided that in addition to updating the existing homepage an alternative would be offered. Drawing on theory relating to user interface design,learning styles and creative thinking, an Alternative Library navigation system was added to the more traditional library homepage. The aim was to provide students with a different way to explore and discover the wide range of information resources available by taking a less formal approach to navigation based on the metaphor of physical space and playful exploration
Participatory Transformations
Learning, in its many forms, from the classroom to independent study, is being transformed by new practices emerging around Internet use. Conversation, participation and community have become watchwords for the processes of learning promised by the Internet and accomplished via technologies such as bulletin boards, wikis, blogs, social software and repositories, devices such as laptops, cell phones and digital cameras, and infrastructures of internet connection, telephone, wireless and broadband. This chapter discusses the impact of emergent, participatory trends on education. In learning and teaching participatory trends harbinge a radical transformation in who learns from whom, where, under what circumstances, and for what and whose purpose. They bring changes in where we find information, who we learn from, how learning progresses, and how we contribute to our learning and the learning of others. These trends indicate a transformation to "ubiquitous learning" ??? a continuous anytime, anywhere, anyone contribution and retrieval of learning materials and advice on and through the Internet and its technologies, niches and social spaces.not peer reviewe
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