338 research outputs found
Segmental Spatiotemporal CNNs for Fine-grained Action Segmentation
Joint segmentation and classification of fine-grained actions is important
for applications of human-robot interaction, video surveillance, and human
skill evaluation. However, despite substantial recent progress in large-scale
action classification, the performance of state-of-the-art fine-grained action
recognition approaches remains low. We propose a model for action segmentation
which combines low-level spatiotemporal features with a high-level segmental
classifier. Our spatiotemporal CNN is comprised of a spatial component that
uses convolutional filters to capture information about objects and their
relationships, and a temporal component that uses large 1D convolutional
filters to capture information about how object relationships change across
time. These features are used in tandem with a semi-Markov model that models
transitions from one action to another. We introduce an efficient constrained
segmental inference algorithm for this model that is orders of magnitude faster
than the current approach. We highlight the effectiveness of our Segmental
Spatiotemporal CNN on cooking and surgical action datasets for which we observe
substantially improved performance relative to recent baseline methods.Comment: Updated from the ECCV 2016 version. We fixed an important
mathematical error and made the section on segmental inference cleare
Magnetoelectric Effect at the Ni/HfO\u3csub\u3e2\u3c/sub\u3e Interface Induced by Ferroelectric Polarization
Driven by the technological importance of the recently discovered ferroelectric HfO2, we explore a magnetoelectric effect at the HfO2-based ferroelectric-ferromagnetic interface. Using density-functionaltheory calculations of the Ni/HfO2/Ni (001) heterostructure as a model system, we predict a stable and sizable ferroelectric polarization in a few-nm-thick HfO2 layer. For the Ni/HfO2 interface with opposite polarization directions (pointing to or away from the interface), we find a sizable difference in the interfacial Ni—O bonding, resulting in dissimilar degrees of depletion of the electron density around the interface. The latter affects the relative population of the exchange-split majority and minority spin bands at the interface and thus the interfacial magnetic moments. The sizable change in the interface magnetization with ferroelectric polarization reversal of HfO2 manifests a significant ferroelectrically induced magnetoelectric effect at the Ni/HfO2 interface. Our results reveal promising prospects of ferroelectric-ferromagnetic composite multiferroics based on HfO2-based ferroelectric materials
A fingerprint based crypto-biometric system for secure communication
To ensure the secure transmission of data, cryptography is treated as the
most effective solution. Cryptographic key is an important entity in this
procedure. In general, randomly generated cryptographic key (of 256 bits) is
difficult to remember. However, such a key needs to be stored in a protected
place or transported through a shared communication line which, in fact, poses
another threat to security. As an alternative, researchers advocate the
generation of cryptographic key using the biometric traits of both sender and
receiver during the sessions of communication, thus avoiding key storing and at
the same time without compromising the strength in security. Nevertheless, the
biometric-based cryptographic key generation possesses few concerns such as
privacy of biometrics, sharing of biometric data between both communicating
users (i.e., sender and receiver), and generating revocable key from
irrevocable biometric. This work addresses the above-mentioned concerns.
In this work, a framework for secure communication between two users using
fingerprint based crypto-biometric system has been proposed. For this,
Diffie-Hellman (DH) algorithm is used to generate public keys from private keys
of both sender and receiver which are shared and further used to produce a
symmetric cryptographic key at both ends. In this approach, revocable key for
symmetric cryptography is generated from irrevocable fingerprint. The biometric
data is neither stored nor shared which ensures the security of biometric data,
and perfect forward secrecy is achieved using session keys. This work also
ensures the long-term security of messages communicated between two users.
Based on the experimental evaluation over four datasets of FVC2002 and NIST
special database, the proposed framework is privacy-preserving and could be
utilized onto real access control systems.Comment: 29 single column pages, 8 figure
- …