14,512 research outputs found
Multi-scale Orderless Pooling of Deep Convolutional Activation Features
Deep convolutional neural networks (CNN) have shown their promise as a
universal representation for recognition. However, global CNN activations lack
geometric invariance, which limits their robustness for classification and
matching of highly variable scenes. To improve the invariance of CNN
activations without degrading their discriminative power, this paper presents a
simple but effective scheme called multi-scale orderless pooling (MOP-CNN).
This scheme extracts CNN activations for local patches at multiple scale
levels, performs orderless VLAD pooling of these activations at each level
separately, and concatenates the result. The resulting MOP-CNN representation
can be used as a generic feature for either supervised or unsupervised
recognition tasks, from image classification to instance-level retrieval; it
consistently outperforms global CNN activations without requiring any joint
training of prediction layers for a particular target dataset. In absolute
terms, it achieves state-of-the-art results on the challenging SUN397 and MIT
Indoor Scenes classification datasets, and competitive results on
ILSVRC2012/2013 classification and INRIA Holidays retrieval datasets
Dynamic trust models for ubiquitous computing environments
A significant characteristic of ubiquitous computing is the need for interactions of highly mobile entities to be secure: secure both for the entity and the environment in which the entity operates. Moreover, ubiquitous computing is also characterised by partial views over the state of the global environment, implying that we cannot guarantee that an environment can always verify the properties of the mobile entity that it has just received. Secure in this context encompasses both the need for cryptographic security and the need for trust, on the part of both parties, that the interaction is functioning as expected. In this paper we make a broad assumption that trust and cryptographic security can be considered as orthogonal concerns (i.e. an entity might encrypt a deliberately incorrect answer to a legitimate request). We assume the existence of reliable encryption techniques and focus on the characteristics of a model that supports the management of the trust relationships between two entities during an interaction in a ubiquitous environment
A tutorial task and tertiary courseware model for collaborative learning communities
RAED provides a computerised infrastructure to support the development and administration of Vicarious Learning in collaborative learning communities spread across multiple universities and workplaces. The system is based on the OASIS middleware for Role-based Access Control. This paper describes the origins of the model and the approach to implementation and outlines some of its benefits to collaborative teachers and learners
Associations between fibrin D-dimer, markers of inflammation, incident self-reported mobility limitation, and all-cause mortality in older men
Objectives<p></p>
To examine the independent relationships between fibrin D-dimer, interleukin 6 (IL-6), C-reactive protein (CRP), and fibrinogen and incident mobility limitation and mortality.<p></p>
Design<p></p>
Prospective.<p></p>
Setting<p></p>
General practice in 24 British towns.<p></p>
Participants<p></p>
Men aged 60 to 79 without prevalent heart failure followed up for an average of 11.5 years (N = 3,925).<p></p>
Measurements<p></p>
All-cause mortality (n = 1,286) and self-reported mobility disability obtained at examination in 1998 to 2000 and in a postal questionnaire 3 to 5 years later in 2003.<p></p>
Results<p></p>
High D-dimer (top vs lowest tertile: adjusted odds ratio (aOR) = 1.46, 95% confidence interval = 1.02â2.05) and IL-6 (aOR = 1.43, 95% CI = 1.01â2.02) levels (but not CRP or fibrinogen) were associated with greater incident mobility limitation after adjustment for confounders and prevalent disease status. IL-6, CRP, fibrinogen, and D-dimer were significantly associated with total mortality after adjustment for confounders. Only D-dimer and IL-6 predicted total mortality independent of each other and the other biomarkers. The adjusted hazard ratio (aHR) was 1.16 (95% CI = 1.10â1.22) for a standard deviation increase in log D-dimer and 1.10 (95% CI = 1.04â1.18) for a standard deviation increase in log IL-6. D-dimer was independently related to vascular and nonvascular mortality, and IL-6 was independently related to vascular mortality. Risks of mobility limitation and mortality were greatest in those with a combination of high D-dimer and IL-6 levels.<p></p>
Conclusion<p></p>
D-dimer and IL-6 are associated with risk of mobility limitation and mortality in older men without heart failure. The findings suggest that coagulation leads to functional decline and mortality s that inflammation does not explain
Object Matching in Distributed Video Surveillance Systems by LDA-Based Appearance Descriptors
Establishing correspondences among object instances is still challenging in multi-camera surveillance systems, especially when the camerasâ fields of view are non-overlapping. Spatiotemporal constraints can help in solving the correspondence problem but still leave a wide margin of uncertainty. One way to reduce this uncertainty is to use appearance information about the moving objects in the site. In this paper we present the preliminary results of a new method that can capture salient appearance characteristics at each camera node in the network. A Latent Dirichlet Allocation (LDA) model is created and maintained at each node in the camera network. Each object is encoded in terms of the LDA bag-of-words model for appearance. The encoded appearance is then used to establish probable matching across cameras. Preliminary experiments are conducted on a dataset of 20 individuals and comparison against Maddenâs I-MCHR is reported
Probabilistic Search for Object Segmentation and Recognition
The problem of searching for a model-based scene interpretation is analyzed
within a probabilistic framework. Object models are formulated as generative
models for range data of the scene. A new statistical criterion, the truncated
object probability, is introduced to infer an optimal sequence of object
hypotheses to be evaluated for their match to the data. The truncated
probability is partly determined by prior knowledge of the objects and partly
learned from data. Some experiments on sequence quality and object segmentation
and recognition from stereo data are presented. The article recovers classic
concepts from object recognition (grouping, geometric hashing, alignment) from
the probabilistic perspective and adds insight into the optimal ordering of
object hypotheses for evaluation. Moreover, it introduces point-relation
densities, a key component of the truncated probability, as statistical models
of local surface shape.Comment: 18 pages, 5 figure
Using simulated co-heating tests to understand weather driven sources of uncertainty within the co-heating test method
The so-called performance gap between designed and as-built
building performance threatens to undermine carbon reduction strategies in the built environment. Field measurements
to date have indicated that the measured as-built fabric heat
loss of tested UK buildings is consistently higher than design
values, often considerably so. Currently, our lack of knowledge
over the extent of this gap, and the processes that cause it, is
compounded by a lack of robust post-construction evaluation
tools. Much of this post-construction evaluation work is based,
in part, on the use of co-heating tests: a method utilising an
energy balance to determine the heat loss across the entire
building envelope, defined by the heat loss coefficient (W/K).
However, the errors associated with co-heating are not well
understood or typically addressed in the literature. Furthermore, the test procedure requires a building to be unoccupied
for two to three weeks and is therefore often cited as costly and
unsuitable both for developers and as a policy tool. In order to
improve the application of this test method it is crucial firstly to
understand the sources of uncertainty in co-heating tests and
the âsteady-stateâ energy balance they are based upon. However,
with a small database of tests performed to date it is difficult to
discern these sources of error. This paper presents the results
of a method using simulated co-heating tests to show how key
weather variables influence the co-heating result and generate
uncertainty and bias. In particular the effects of short-wave solar and long-wave sky radiation are presented. Improvements to the co-heating method can be derived from this; in particular the need to consider when dwellings should be tested to
avoid large solar-generated errors and the importance of a accurately calculated solar aperture. Recommendations also include the local measurement of sky radiation to avoid outlying
data points, bias in the measurement and discrepancies when
comparing design and as-built heat loss
A study of blood contamination of Siqveland matrix bands
AIMS To use a sensitive forensic test to measure blood contamination of used Siqveland matrix bands following routine cleaning and sterilisation procedures in general dental practice. MATERIALS AND METHODS: Sixteen general dental practices in the West of Scotland participated. Details of instrument cleaning procedures were recorded for each practice. A total of 133 Siqveland matrix bands were recovered following cleaning and sterilisation and were examined for residual blood contamination by the Kastle-Meyer test, a well-recognised forensic technique. RESULTS: Ultrasonic baths were used for the cleaning of 62 (47%) bands and retainers and the remainder (53%) were hand scrubbed prior to autoclaving. Overall, 21% of the matrix bands and 19% of the retainers gave a positive Kastle-Meyer test, indicative of residual blood contamination, following cleaning and sterilisation. In relation to cleaning method, 34% of hand-scrubbed bands and 32% of hand-scrubbed retainers were positive for residual blood by the Kastle-Meyer test compared with 6% and 3% respectively of ultrasonically cleaned bands and retainers (P less than 0.001). CONCLUSIONS: If Siqveland matrix bands are re-processed in the assembled state, then adequate pre-sterilisation cleaning cannot be achieved reliably. Ultrasonic baths are significantly more effective than hand cleaning for these items of equipment
Instrumentation for hydrogen slush storage containers
Hydrogen liquid and slush tank continuous inventory during ground storag
Comments on the black hole information problem
String theory provides numerous examples of duality between gravitational
theories and unitary gauge theories. To resolve the black hole information
paradox in this setting, it is necessary to better understand how unitarity is
implemented on the gravity side. We argue that unitarity is restored by
nonlocal effects whose initial magnitude is suppressed by the exponential of
the Bekenstein-Hawking entropy. Time-slicings for which effective field theory
is valid are obtained by demanding the mutual back-reaction of quanta be small.
The resulting bounds imply that nonlocal effects do not lead to observable
violations of causality or conflict with the equivalence principle for
infalling observers, yet implement information retrieval for observers who stay
outside the black hole.Comment: 18 pages, 2 figures, revtex, v2 figure added and some improvements to
presentatio
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