New approaches to encryption and steganography for digital videos

In this work we propose a novel type of digital video encryption that has several advantages over other currently available digital video encryption schemes. We also present an extended classification of digital video encryption algorithms in order to clarify these advantages. We analyze both security and performance aspects of the proposed method, and show that the method is efficient and secure from a cryptographic point of view. Even though the method is currently feasible only for a certain class of video sequences and video codecs, the method is promising and future investigations might reveal its broader applicability. Finally, we extend our approach into a novel type of digital video steganography where it is possible to disguise a given video with another video.     

Magnetic nerve root stimulation in two types of brachial plexus injury: segmental demyelination and axonal degeneration

Magnetic cervical nerve root stimulation was performed in 9 patients with plexopathies secondary to suspension (SP) and in 12 cases with neurogenic thoracic outlet syndrome (NTOS). The findings were compared with those of the previously reported case groups: n-hexane polyneuropathy (HPNP), inflammatory demyelinating polyneuropathy (IDP), and motor neuron disease (MND). Muscle responses elicited by magnetic stimulation had very high rates of amplitude and area loss in the neck-axilla segments of the 6 SP patients. This, along with the other electrophysiological findings, suggested the presence of segmentally demyelinating plexus lesions. In NTOS patients, magnetic stimulation findings were not significantly different from those of the controls. Neck-axilla segment amplitude and are reduction rates in SP and IDP patients were significantly higher than those found in NTOS, HPNP, and MND groups, implying that magnetic nerve root stimulation may have a role in the demonstration of segmentally demyelinating lesions involving proximal nerve segments.     

Automatic separation of compound figures in scientific articles

Multimedia Tools and Applications - Content-based analysis and retrieval of digital images found in scientific articles is often hindered by images consisting of multiple subfigures (compound...     

On the use of variable stride in convolutional neural networks

This paper explores the idea of changing the stride value in convolutional neural networks depending on the position of the pixel within the image: a smaller stride value is used when processing the center of the image, while a larger one is used for pixels close to the edges. We show several examples of image classification tasks where the proposed approach outperforms a baseline solution of same computational cost using fixed stride and several counterexamples where it does not – and explain why this is so. The proposed method has been successfully tested using several contemporary datasets and can be easily implemented and extended to other image classification tasks.

     

Ferrochromium slag as a protective coating material against oxidation for caster rolls

In this study, ferrochromium (FeCr) slag, which is available as an industrial waste, is proposed as a protective surface coating material particularly for protection of continuous casting rolls against oxidation. FeCr slag was successfully deposited with atmospheric plasma spray (APS) method. Before the coating process, FeCr slag powder prepared in the particle size range of 5‐38 μm, was investigated using conventional characterization methods (XRD, SEM, TGA etc.). Thermal Barrier Coating (TBC) system was used as a basis for deposition processes. Accordingly, NiCoCrAlY (Amdry, ?45 + 5 μm) was firstly deposited as metallic bond coat layer onto the surface of AISI 420 substrate, and then FeCr slag layer was deposited as the top coating layer. After the deposition of FeCr slag powder, the resulting coating layer was found to have low porosity with a homogeneous microstructure. The deposited FeCr slag coatings were subjected to isothermal oxidation tests at different temperatures and test durations for determination of their oxidation behavior and upper operating temperature limits. The results obtained from this study indicate that FeCr slag can be considered as an alternative protective coating material for caster rolls which are subjected to high temperatures up to 800°C.     

Innovative directions in self-organized distributed multimedia systems

The way by which multimedia contents are produced, delivered across networks, and consumed by intended users have shifted significantly during the past 10 years. In this paper we postulate that, in the near future, flexible and self-organizing facilities will play a dominating role in distributed multimedia systems. We discuss how such systems can be designed, using a three-layer (sensor, distribution, and user layer) architecture, SOMA (Self Organizing Multimedia Architecture), as an example. We also present innovative directions in three main aspects of self-organized multimedia systems: (i) the self-organizing aspects of multimedia user communities, e.g., the wisdom, intentions, and needs of users; (ii) a fresh look at video streams that treat them as a collection of units that can be composed taking user and network aspects into account; and (iii) new delivery paradigms and how self-organization and multimedia delivery can be combined.     

Sparsity in optical flow and trajectories

In this article, we apply sparse constraints to improve optical flow and trajectories. We apply sparsity in two ways. First, with two-frame optical flow, we enforce a sparse representation of flow patches using a learned overcomplete dictionary. Second, we apply a low-rank constraint to trajectories via robust coupling. Optical flow is an ill-posed underconstrained inverse problem. Many recent approaches use total variation to constrain the flow solution to satisfy color constancy. In our first results presented, we find that learning a 2D overcomplete dictionary from the total variation result and then enforcing a sparse constraint on the flow improves the result. A new technique using partially overlapping patches accelerates the calculation. This approach is implemented in a coarse-to-fine strategy. Our results show that combining total variation and a sparse constraint from a learned dictionary is more effective than total variation alone. In the second part, we compute optical flow and trajectories from an image sequence. Sparsity in trajectories is measured by matrix rank. We introduce a low-rank constraint of linear complexity using random subsampling of the data. We demonstrate that, by using a robust coupling with the low-rank constraint, our approach outperforms baseline methods on general image sequences.