3,064 research outputs found
Supporting novel home network management interfaces with Openflow and NOX
The Homework project has examined redesign of existing home network infrastructures to better support the needs and requirements of actual home users. Integrating results from several ethnographic studies, we have designed and built a home networking platform providing detailed per-flow measurement and management capabilities supporting several novel management interfaces. This demo specifically shows these new visualization and control interfaces, and describes the broader benefits of taking an integrated view of the networking infrastructure, realised through our router's augmented measurement and control APIs.
Aspects of this work have been published: the Homework Database in Internet Management (IM) 2011 and implications of the ethnographic results are to appear at the SIGCOMM W-MUST workshop 2011. Separate, more detailed expositions of the interface elements and system performance and implications are currently under submission at other venues. A partial code release is already available and we anticipate fuller public beta release by Q4 2011
Inside Out: Detecting Learners' Confusion to Improve Interactive Digital Learning Environments
Confusion is an emotion that is likely to occur while learning complex information. This emotion can be beneficial to learners in that it can foster engagement, leading to deeper understanding. However, if learners fail to resolve confusion, its effect can be detrimental to learning. Such detrimental learning experiences are particularly concerning within digital learning environments (DLEs), where a teacher is not physically present to monitor learner engagement and adapt the learning experience accordingly. However, with better information about a learner's emotion and behavior, it is possible to improve the design of interactive DLEs (IDLEs) not only in promoting productive confusion but also in preventing overwhelming confusion. This article reviews different methodological approaches for detecting confusion, such as self-report and behavioral and physiological measures, and discusses their implications within the theoretical framework of a zone of optimal confusion. The specificities of several methodologies and their potential application in IDLEs are discussed
Loss of solutions in shear banding fluids in shear banding fluids driven by second normal stress differences
Edge fracture occurs frequently in non-Newtonian fluids. A similar
instability has often been reported at the free surface of fluids undergoing
shear banding, and leads to expulsion of the sample. In this paper the
distortion of the free surface of such a shear banding fluid is calculated by
balancing the surface tension against the second normal stresses induced in the
two shear bands, and simultaneously requiring a continuous and smooth meniscus.
We show that wormlike micelles typically retain meniscus integrity when shear
banding, but in some cases can lose integrity for a range of average applied
shear rates during which one expects shear banding. This meniscus fracture
would lead to ejection of the sample as the shear banding region is swept
through. We further show that entangled polymer solutions are expected to
display a propensity for fracture, because of their much larger second normal
stresses. These calculations are consistent with available data in the
literature. We also estimate the meniscus distortion of a three band
configuration, as has been observed in some wormlike micellar solutions in a
cone and plate geometry.Comment: 23 pages, to be published in Journal of Rheolog
Case Hepatic Endometriosis: A Continuing Diagnostic Dilemma
Background. Intraparenchymal endometriosis of liver is rare. It may present as liver tumour and the diagnosis is not usually established till after surgery.
Case Outline. A 48-year-old postmenopausal woman presented with right upper quadrant pain and a cystic liver mass. Liver function tests and tumour markers (αFP, CEA, CA 19-9, and CA 125) were normal. Radiological imaging (USS, CT and MRI) suggested a thick walled cystic mass involving segments IV and VIII with complex intracystic septations. Frozen section at operation suggested a benign cystadenoma. The cyst was enucleated using a CUSA (Cavitron ultrasonic aspirator). The final histology confirmed endometriosis.
Discussion. Eleven cases of hepatic endometrioma have been reported and only four in postmenopausal women. Preoperative diagnosis poses a challenge and so far none of the cases have been diagnosed preoperatively. Surgery remains the treatment of choice. Accurate diagnosis at time of operation may avoid extensive liver surgery and its associated morbidity
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Birds of a Feather Are Punished Together, or Not? Examining Heterogeneity in Career Advancements of Minority Groups
In this study we examine the heterogeneous effects of being affiliated with different minority groups on employees’ career advancements in organizations. We draw on the categories literature and its concept of category distance to hypothesize why some minority groups may be more (dis)advantaged than others in their career advancements. To do so, we define category distance in terms of shared identity markers between groups, where identity markers are salient attributes that audiences commonly associate a group with. We test our hypotheses among religious minority groups using employment data from a large Indonesian government organization. Our results indicate that minority groups closer in distance to the organizational majority group are more penalized in their career advancements than minority groups further in distance. These results hold both at the group and at the individual level. Through our study we make contributions to the literatures on careers, categories, and the burgeoning study of religion in organizations. We conclude with implications for practice
Enabling the new economic actor: data protection, the digital economy, and the Databox
This paper offers a sociological perspective on data protection regulation and its relevance to design. From this perspective, proposed regulation in Europe and the USA seeks to create a new economic actor—the consumer as personal data trader—through new legal frameworks that shift the locus of agency and control in data processing towards the individual consumer or “data subject”. The sociological perspective on proposed data regulation recognises the reflexive relationship between law and the social order, and the commensurate needs to balance the demand for compliance with the design of computational tools that enable this new economic actor. We present the Databox model as a means of providing data protection and allowing the individual to exploit personal data to become an active player in the emerging data economy.The authors acknowledge the support of the EPSRC, Grants EP/M001636/1, EP/M02315X/1, EP/N028260/1, and EU FP7 Grant 611001.This is the final version of the article. It first appeared from [PUBLISHER] via http://dx.doi.org/10.1007/s00779-016-0939-
The Sagnac Phase Shift suggested by the Aharonov-Bohm effect for relativistic matter beams
The phase shift due to the Sagnac Effect, for relativistic matter beams
counter-propagating in a rotating interferometer, is deduced on the bases of a
a formal analogy with the the Aharonov-Bohm effect. A procedure outlined by
Sakurai, in which non relativistic quantum mechanics and newtonian physics
appear together with some intrinsically relativistic elements, is generalized
to a fully relativistic context, using the Cattaneo's splitting technique. This
approach leads to an exact derivation, in a self-consistently relativistic way,
of the Sagnac effect. Sakurai's result is recovered in the first order
approximation.Comment: 18 pages, LaTeX, 2 EPS figures. To appear in General Relativity and
Gravitatio
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Teamworking under Lean in UK public services: lean teams and team targets in Her Majesty's Revenue & Customs (HMRC)
The authors of The Machine that Changed the World were in no doubt about the importance of teamworking in lean production: ‘in the end’, they say [Womack, J., Jones, D, & Roos, D. (1990). The machine that changed the world. New York: Rawson Associates, p. 99], ‘it is the dynamic work team that emerges as the heart of the lean factory’. It is with this bold statement in mind that we seek to explore and develop our conceptual and practical understanding of how teamworking operates under Lean. We examine these issues in the context of a high-profile case of Lean implementation in the UK public sector, the Pacesetter programme of the UK's tax assessment and collection service, Her Majesty's Revenue & Customs (HMRC). We find that although the teams themselves were ostensibly set up on a lean basis, they were largely unable to operate as such as a result of the pressures they faced to meet their work targets. The operation of the teams thus retained, and was shaped by, characteristics of the pre-existing ‘target-based’ mode of teamworking. This, in turn, suggests particular ways in which we might better understand how Lean interacts with the context or environment into which it is introduced. These findings also to some degree run counter to the overwhelmingly negative account of Lean put forward in other recent studies of HMRC [e.g. Carter, B., Danford, A., Howcroft, D., Richardson, H., Smith, A., & Taylor, P. (2013a). Taxing times: Lean working and the creation of (in)efficiencies in HM Revenue and Customs. Public Administration, 91, 83–97]
Short Time Behavior in De Gennes' Reptation Model
To establish a standard for the distinction of reptation from other modes of
polymer diffusion, we analytically and numerically study the displacement of
the central bead of a chain diffusing through an ordered obstacle array for
times . Our theory and simulations agree quantitatively and show
that the second moment approaches the often viewed as signature of
reptation only after a very long transient and only for long chains (N > 100).
Our analytically solvable model furthermore predicts a very short transient for
the fourth moment. This is verified by computer experiment.Comment: 4 pages, revtex, 4 ps file
Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model
Several firing patterns experimentally observed in neural populations have
been successfully correlated to animal behavior. Population bursting, hereby
regarded as a period of high firing rate followed by a period of quiescence, is
typically observed in groups of neurons during behavior. Biophysical
membrane-potential models of single cell bursting involve at least three
equations. Extending such models to study the collective behavior of neural
populations involves thousands of equations and can be very expensive
computationally. For this reason, low dimensional population models that
capture biophysical aspects of networks are needed.
\noindent The present paper uses a firing-rate model to study mechanisms that
trigger and stop transitions between tonic and phasic population firing. These
mechanisms are captured through a two-dimensional system, which can potentially
be extended to include interactions between different areas of the nervous
system with a small number of equations. The typical behavior of midbrain
dopaminergic neurons in the rodent is used as an example to illustrate and
interpret our results.
\noindent The model presented here can be used as a building block to study
interactions between networks of neurons. This theoretical approach may help
contextualize and understand the factors involved in regulating burst firing in
populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded
as separate file
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