12,202 research outputs found
Use of FBG optical sensors for structural health monitoring: Practical application
This paper describes the development of FBG Optical sensors for their practical application on structural health monitoring. The sensors were installed on the Tsing Ma Bridge for a trial run. The results using FBG sensors were in excellent agreement with those acquired by the bridge WASHMS
Connections between Operator-splitting Methods and Deep Neural Networks with Applications in Image Segmentation
Deep neural network is a powerful tool for many tasks. Understanding why it
is so successful and providing a mathematical explanation is an important
problem and has been one popular research direction in past years. In the
literature of mathematical analysis of deep deep neural networks, a lot of
works are dedicated to establishing representation theories. How to make
connections between deep neural networks and mathematical algorithms is still
under development. In this paper, we give an algorithmic explanation for deep
neural networks, especially in their connection with operator splitting and
multigrid methods. We show that with certain splitting strategies,
operator-splitting methods have the same structure as networks. Utilizing this
connection and the Potts model for image segmentation, two networks inspired by
operator-splitting methods are proposed. The two networks are essentially two
operator-splitting algorithms solving the Potts model. Numerical experiments
are presented to demonstrate the effectiveness of the proposed networks
PottsMGNet: A Mathematical Explanation of Encoder-Decoder Based Neural Networks
For problems in image processing and many other fields, a large class of
effective neural networks has encoder-decoder-based architectures. Although
these networks have made impressive performances, mathematical explanations of
their architectures are still underdeveloped. In this paper, we study the
encoder-decoder-based network architecture from the algorithmic perspective and
provide a mathematical explanation. We use the two-phase Potts model for image
segmentation as an example for our explanations. We associate the segmentation
problem with a control problem in the continuous setting. Then, multigrid
method and operator splitting scheme, the PottsMGNet, are used to discretize
the continuous control model. We show that the resulting discrete PottsMGNet is
equivalent to an encoder-decoder-based network. With minor modifications, it is
shown that a number of the popular encoder-decoder-based neural networks are
just instances of the proposed PottsMGNet. By incorporating the
Soft-Threshold-Dynamics into the PottsMGNet as a regularizer, the PottsMGNet
has shown to be robust with the network parameters such as network width and
depth and achieved remarkable performance on datasets with very large noise. In
nearly all our experiments, the new network always performs better or as good
on accuracy and dice score than existing networks for image segmentation
In-plane dielectric properties of epitaxial 0.65Pb(Mg[sub ⅓]Nb[sub ⅔])O₃-0.35 PbTiO₃ thin films in a very wide frequency range
Author name used in this publication: Y. WangAuthor name used in this publication: H. L. W. ChanAuthor name used in this publication: C. L. ChoyAuthor name used in this publication: K. C. Cheng2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Suicide in Hong Kong: A case-control psychological autopsy study
Background. The relative contribution of psychosocial and clinical risk factors to suicide among Chinese populations is an important issue. In Hong Kong, this issue requires vigorous examination in light of a 50% increase in suicide rate between 1997 and 2003. Method. Using a case-control psychological autopsy method, 150 suicide deceased were compared with 150 living controls matched by age and gender. Semi-structured interviews were conducted with the next-of-kin of the subjects. Data were collected on a wide range of potential risk and protective factors, including demographic, life event, clinical and psychological variables. The relative contribution of these factors towards suicide was examined in a multiple logistic regression model. Results. Six factors were found to significantly and independently contribute to suicide: unemployment, indebtedness, being single, social support, psychiatric illness, and history of past attempts. Conclusions. Both psychosocial and clinical factors are important in suicides in Hong Kong. They seem to have mediated suicide risk independently. In addition, socio-economic adversities seem to have played a relatively important role in the increasing suicide rate in Hong Kong. © 2006 Cambridge University Press.published_or_final_versio
Neurobiological underpinnings of sensation seeking trait in heroin abusers
published_or_final_versio
- …